Patent Publication Number: US-2022233264-A1

Title: Manipulation of an elongated medical device

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application claims the benefit of Provisional Application No. 62/874,173 (Atty Dkt C130-338) entitled MANIPULATION OF AN ELONGATED MEDICAL DEVICE and filed on Jul. 15, 2019. 
    
    
     FIELD 
     The present invention relates generally to the field of robotic medical procedure systems and, in particular, to apparatus and methods for robotically controlling the movement and operation of elongated medical devices. 
     BACKGROUND 
     Catheters and other elongated medical devices (EMDs) may be used for minimally invasive medical procedures for the diagnosis and treatment of diseases of various vascular systems, including neurovascular intervention (NVI) also known as neurointerventional surgery, percutaneous coronary intervention (PCI) and peripheral vascular intervention (PVI). These procedures typically involve navigating a guidewire through the vasculature, and via the guidewire advancing a catheter to deliver therapy. The catheterization procedure starts by gaining access into the appropriate vessel, such as an artery or vein, with an introducer sheath using standard percutaneous techniques. Through the introducer sheath, a sheath or guide catheter is then advanced over a diagnostic guidewire to a primary location such as an internal carotid artery for NVI, a coronary ostium for PCI, or a superficial femoral artery for PVI. A guidewire suitable for the vasculature is then navigated through the sheath or guide catheter to a target location in the vasculature. In certain situations, such as in tortuous anatomy, a support catheter or microcatheter is inserted over the guidewire to assist in navigating the guidewire. The physician or operator may use an imaging system (e.g., fluoroscope) to obtain a cine with a contrast injection and select a fixed frame for use as a roadmap to navigate the guidewire or catheter to the target location, for example, a lesion. Contrast-enhanced images are also obtained while the physician delivers the guidewire or catheter so that the physician can verify that the device is moving along the correct path to the target location. While observing the anatomy using fluoroscopy, the physician manipulates the proximal end of the guidewire or catheter to direct the distal tip into the appropriate vessels toward the lesion or target anatomical location and avoid advancing into side branches. 
     Robotic catheter-based procedure systems have been developed that may be used to aid a physician in performing catheterization procedures such as, for example, NVI, PCI and PVI. Examples of NVI procedures include coil embolization of aneurysms, liquid embolization of arteriovenous malformations and mechanical thrombectomy of large vessel occlusions in the setting of acute ischemic stroke. In an NVI procedure, the physician uses a robotic system to gain target lesion access by controlling the manipulation of a neurovascular guidewire and microcatheter to deliver the therapy to restore normal blood flow. Target access is enabled by the sheath or guide catheter but may also require an intermediate catheter for more distal territory or to provide adequate support for the microcatheter and guidewire. The distal tip of a guidewire is navigated into, or past, the lesion depending on the type of lesion and treatment. For treating aneurysms, the microcatheter is advanced into the lesion and the guidewire is removed and several embolization coils are deployed into the aneurysm through the microcatheter and used to block blood flow into the aneurysm. For treating arteriovenous malformations, a liquid embolic is injected into the malformation via a microcatheter. Mechanical thrombectomy to treat vessel occlusions can be achieved either through aspiration and/or use of a stent retriever. Depending on the location of the clot, aspiration is either done through an aspiration catheter, or through a microcatheter for smaller arteries. Once the aspiration catheter is at the lesion, negative pressure is applied to remove the clot through the catheter. Alternatively, the clot can be removed by deploying a stent retriever through the microcatheter. Once the clot has integrated into the stent retriever, the clot is retrieved by retracting the stent retriever and microcatheter (or intermediate catheter) into the guide catheter. 
     In PCI, the physician uses a robotic system to gain lesion access by manipulating a coronary guidewire to deliver the therapy and restore normal blood flow. The access is enabled by seating a guide catheter in a coronary ostium. The distal tip of the guidewire is navigated past the lesion and, for complex anatomies, a microcatheter may be used to provide adequate support for the guidewire. The blood flow is restored by delivering and deploying a stent or balloon at the lesion. The lesion may need preparation prior to stenting, by either delivering a balloon for pre-dilation of the lesion, or by performing atherectomy using, for example, a laser or rotational atherectomy catheter and a balloon over the guidewire. Diagnostic imaging and physiological measurements may be performed to determine appropriate therapy by using imaging catheters or fractional flow reserve (FFR) measurements. 
     In PVI, the physician uses a robotic system to deliver the therapy and restore blood flow with techniques similar to NVI. The distal tip of the guidewire is navigated past the lesion and a microcatheter may be used to provide adequate support for the guidewire for complex anatomies. The blood flow is restored by delivering and deploying a stent or balloon to the lesion. As with PCI, lesion preparation and diagnostic imaging may be used as well. 
     When support at the distal end of a catheter or guidewire is needed, for example, to navigate tortuous or calcified vasculature, to reach distal anatomical locations, or to cross hard lesions, an over-the-wire (OTW) catheter or coaxial system is used. An OTW catheter has a lumen for the guidewire that extends the full length of the catheter. This provides a relatively stable system because the guidewire is supported along the whole length. This system, however, has some disadvantages, including higher friction, and longer overall length compared to rapid-exchange catheters (see below). Typically to remove or exchange an OTW catheter while maintaining the position of the indwelling guidewire, the exposed length (outside of the patient) of guidewire must be longer than the OTW catheter. A 300 cm long guidewire is typically sufficient for this purpose and is often referred to as an exchange length guidewire. Due to the length of the guidewire, two operators are needed to remove or exchange an OTW catheter. This becomes even more challenging if a triple coaxial, known in the art as a tri-axial system, is used (quadruple coaxial catheters have also been known to be used). However, due to its stability, an OTW system is often used in NVI and PVI procedures. On the other hand, PCI procedures often use rapid exchange (or monorail) catheters. The guidewire lumen in a rapid exchange catheter runs only through a distal section of the catheter, called the monorail or rapid exchange (RX) section. With a RX system, the operator manipulates the interventional devices parallel to each other (as opposed to with an OTW system, in which the devices are manipulated in a serial configuration), and the exposed length of guidewire only needs to be slightly longer than the RX section of the catheter. A rapid exchange length guidewire is typically 180-200 cm long. Given the shorter length guidewire and monorail, RX catheters can be exchanged by a single operator. However, RX catheters are often inadequate when more distal support is needed. 
     SUMMARY 
     An EMD drive system includes an on-device adapter removably fixed to a shaft of an EMD. The on-device adapter received in a cassette. The cassette is removably secured to a drive module. The drive module is operatively coupled to the on-device adapter to move the on-device adapter and EMD together. 
     In one embodiment an EMD drive system includes a collet removably fixed to an EMD. The EMD, fixed to the collet, is radially loaded into a robotic drive. An EMD support is removably applied to the EMD from a non-axial direction; and the robotic drive is operatively coupled to the collet to translate and/or rotate the collet and EMD 
     In one embodiment a robotic system includes a robotic drive including a base having a drive coupler. A cassette is removably secured to the base. A collet in the cassette is removably fixed to an EMD. The collet has a driven member being operatively coupled to the drive coupler; and the robotic drive includes a motor operatively coupled to the collet to move the collet 
     In one embodiment a robotic system includes a collet having a first portion having a first collet coupler connected thereto and a second portion having a second collet coupler connected thereto. An EMD is removably located within a pathway defined by the collet. A robotic drive including a base having a first motor and a second motor operatively continuously coupled to both the first collet coupler and the second collet coupler respectively to operatively pinch and unpinch the EMD in the pathway and to rotate the EMD. 
     In one embodiment a collet includes an inner member defining a pathway receiving an EMD and an outer member. A plurality of engagement members releasably engage the EMD as the inner member is moved relative to the outer member. 
     In one embodiment an EMD drive system includes a collet having a collet first member having a first engagement portion. The collet has a second member that is driven. A collet engagement member has a second engagement portion. The collet first member and the collet engagement member move between an engaged position and a disengaged position. The first engagement portion engages the second engagement portion as the collet first member and collet engagement member are moved to the engaged position. Rotation of the collet first member with respect to the collet second member in a first direction in the engaged position pinches an EMD within the collet and rotation of the collet first member with respect to the collect second member in a second direction opposite the first direction unpinches the EMD within the collet. 
     In another embodiment an EMD robotic drive system rotating and translating an EMD with reset instructions, includes a drive module controlled by a control system, the drive module including; a first actuator operatively rotating a first shaft and/or a second shaft; a second actuator operatively translating the first shaft along its longitudinal axis relative to the second shaft from a first position to a second position; a first tire assembly operatively attached to the first shaft; a second tire assembly operatively attached to a second shaft; a third actuator operatively moving the first tire assembly toward and away from the second tire assembly gripping and ungripping an EMD having a longitudinal axis from between the first tire assembly and the second tire assembly. The translation of the first shaft relative to the second shaft rotates the EMD about the longitudinal axis of the EMD, and rotation of the first shaft and/or second shaft translates the EMD along the longitudinal axis of the EMD. A control system provides reset instructions to the third actuator to ungrip the EMD; the second actuator to move the first tire assembly relative to the second tire assembly to a reset position; and the third actuator to grip the EMD. 
     In still another embodiment an EMD robotic drive system comprising a drive module including a first actuator operatively rotating a first shaft and/or a second shaft; a second actuator operatively translating the first shaft along its longitudinal axis relative to the second shaft from a first position to a second position; a first tire assembly removably attached to the first shaft; a second tire assembly removably attached to a second shaft. An EMD having a longitudinal axis is positioned at a first location between the first tire assembly and the second tire assembly. Rotation of the first shaft translates an EMD along its longitudinal axis between the first tire assembly and the second tire assembly; and rotation of the second shaft rotates the EMD about its longitudinal axis. A third actuator operatively moves the first tire assembly toward and away from the second tire assembly gripping and ungripping the EMD from between the first tire assembly and the second tire assembly. A holding clamp releasably clamps a portion of the EMD spaced from the first tire and the second tire along the longitudinal axis of the EMD. 
     In one embodiment an EMD robotic drive system includes a first actuator operatively rotating a first shaft and/or a second shaft. A second actuator operatively translates the first shaft along its longitudinal axis relative to the second shaft from a first position to a second position. A first tire assembly is operatively attached to the first shaft. A second tire assembly is operatively attached to a second shaft. A third actuator operatively moves the first tire assembly toward and away from the second tire assembly gripping and ungripping an EMD having a longitudinal axis from between the first tire assembly and the second tire assembly. Translation of the first shaft relative to the second shaft rotates the EMD about the longitudinal axis of the EMD, and rotation of the first shaft and/or second shaft translates the EMD along the longitudinal axis of the EMD. The first actuator moves with the first shaft as the first shaft is moved along its longitudinal axis away from a home position. 
     In one embodiment a method of robotically moving an EMD includes pinching a shaft of an EMD in an on-device adapter. Removably securing the on-device adapter into a cassette. Removably securing the cassette to a drive module; and robotically moving the on-device adapter and the EMD together in translation along a longitudinal axis of the EMD and/or rotation about the longitudinal axis of the EMD. In a further aspect the method includes unpinching the EMD in the on-device adapter with an actuator when the on-device adapter is secured in the cassette. In a further aspect the method includes unpinching the EMD is robotically controlled with an actuator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of an exemplary catheter procedure system in accordance with an embodiment. 
         FIG. 2  is a schematic block diagram of an exemplary catheter procedure system in accordance with an embodiment. 
         FIG. 3  is an isometric view of an exemplary bedside system of a catheter procedure system in accordance with an embodiment. 
         FIG. 4A  is an exploded isometric view of a device module with a load sensing system and of a cassette that can receive an on-device adapter with an EMD in accordance with an embodiment. 
         FIG. 4B  is an isometric view of a cassette with an on-device adapter with an EMD in accordance with an embodiment. 
         FIG. 4C  is an exploded isometric view of a cassette showing first component and second component of an isolated component. 
         FIG. 4D  is an exploded isometric view of the underside of a cassette and its connection to the drive module. 
         FIG. 4E  is a partial side view of  FIG. 51  showing an on-device adapter with an EMD supported in an isolated component as part of a cassette. 
         FIG. 4F  is a cross-sectional view of the embodiment of  4 A in a position with the EMD in the cassette. 
         FIG. 4G  is an isometric view of a cassette and a device support. 
         FIG. 4H  is a close-up isometric view of a device module of  FIG. 3 . 
         FIG. 5A  is an exploded isometric view of a drive module with drive module base component and load-sensed component. 
         FIG. 5B  is a close-up top view of  FIG. 5A  showing the load-sensed component connected to a load sensor within the drive module base component. 
         FIG. 5C  is a top view of a drive module with a load sensing system including an actuator to rotate and/or pinch/unpinch an EMD located outside the load-sensed component and bearing support of load-sensed component in at least one off-axis (non-measured) direction. 
         FIG. 5D  is a side view of a drive module with a load sensing system including an actuator to rotate and/or pinch/unpinch an EMD located outside the load-sensed component and bearing support of load-sensed component in at least one off-axis (non-measured) direction. 
         FIG. 5E  is an isometric view of a drive module including a load-sensed component and a drive module base component. 
         FIG. 6A  is an exploded side view an EMD on-device adapter in accordance with an embodiment. 
         FIG. 6B  is a side view of the assembled EMD on-device adapter of  FIG. 6A . 
         FIG. 6C  is an exploded isometric view an EMD on-device adapter in accordance with an embodiment. 
         FIG. 6D  is a side view of the assembled EMD on-device adapter of  FIG. 6C . 
         FIG. 7A  is an on-device adapter in accordance with an embodiment. 
         FIG. 7B  is an exploded view of the on-device adapter of  FIG. 7A . 
         FIG. 7C  is an isometric view taken from a generally proximal orientation of the on-device adapter of  FIG. 7A . 
         FIG. 7D  is an isometric view taken from a generally bottom orientation of the on-device adapter of  FIG. 7A . 
         FIG. 7E  is a cross section of the on-device adapter of  FIG. 7A  with the lever in the open position. 
         FIG. 7F  is a cross section of the on-device adapter of  FIG. 7A  with the lever in the closed position. 
         FIG. 8A  is an isometric view of an-device adapter with a catheter. 
         FIG. 8B  is a schematic isometric view of a catheter embodiment used with the on-device adapter of  FIG. 8A . 
         FIG. 9A  is an isometric view of a collet. 
         FIG. 9B  is an isometric view of an inner member of the collet of  FIG. 9A . 
         FIG. 9C  is a view of the collet of  FIG. 9A  taken generally along lines  9 C- 9 C. 
         FIG. 9D  is a top plan view of an inner member of the collet of  FIG. 9A  taken generally along lines  9 D- 9 D in  FIG. 9B . 
         FIG. 9E  is a close-up view of the free end of the inner member of  FIG. 9D . 
         FIG. 9F  is a top plan view of an inner member of the collet of  FIG. 9A  taken generally along lines  9 F- 9 F in  FIG. 9B . 
         FIG. 9G  is an isometric view of another collet. 
         FIG. 9H  is a view of the collet of  FIG. 9G  taken generally along lines  9 H- 9 H. 
         FIG. 9I  is an isometric view of the inner member of  FIG. 9G . 
         FIG. 10A  is an isometric view of a cam-actuated collet. 
         FIG. 10B  is an isometric exploded (assembly) view of  FIG. 10A . 
         FIG. 10C . 1  is a longitudinal cross-sectional view of  FIG. 10A  in the unpinched configuration. 
         FIG. 10C . 2  is a transverse cross-sectional view of  FIG. 10A  in the unpinched configuration. 
         FIG. 10D . 1  is a longitudinal cross-sectional view of  FIG. 10A  in the pinched configuration. 
         FIG. 10D . 2  is a transverse cross-sectional view of  FIG. 10A  in the pinched configuration. 
         FIG. 11A  is a longitudinal cross-sectional view of a flexure-actuated collet. 
         FIG. 11B  is an assembled cross-sectional view of the flexure-actuated collet of  FIG. 11A . 
         FIG. 11C  is an exploded (assembly) view of the flexure-actuated collet of  FIG. 11A . 
         FIG. 11D  is an isometric cross-sectional view of the flexure-actuated collet of  FIG. 11A . 
         FIG. 11E  is an isometric view of a collar of the flexure-actuated collet of  FIG. 11A . 
         FIG. 12A  is an isometric view of a system that includes a double-gear collet-drive assembly. 
         FIG. 12B  is a side view of the double-gear collet-drive assembly of  FIG. 12A . 
         FIG. 12C  is an isometric view of the double-gear collet-drive assembly of  FIG. 12A . 
         FIG. 12D  is an isometric exploded (clamshell) view showing two perspectives of the double-gear collet-drive assembly of  FIG. 12A . 
         FIG. 12E  is an isometric view showing select components of the double-gear collet-drive assembly of  FIG. 12A . 
         FIG. 12F . 1  is a longitudinal cross-sectional top view showing internal components of the double-gear collet-drive assembly of  FIG. 12A  in the unpinched configuration. 
         FIG. 12F . 2  is a longitudinal cross-sectional top view showing internal components of the double-gear collet-drive assembly of  FIG. 12A  in the pinched configuration. 
         FIG. 13A  is an isometric view of a double-gear sliding collet-drive system. 
         FIG. 13B . 1  is a side view of the double-gear sliding collet-drive system of  FIG. 13A  in the proximal configuration. 
         FIG. 13B . 2  is a side view of the double-gear sliding collet-drive system of  FIG. 13A  in the distal configuration. 
         FIG. 13C  is a zoomed-in side view of the collet-and-rotational-drive assembly of  FIG. 13A . 
         FIG. 13D . 1  is a longitudinal cross-sectional side view showing internal components of the double-gear sliding collet-drive assembly of  FIG. 13A  in the unpinched configuration. 
         FIG. 13D . 2  is a longitudinal cross-sectional side view showing internal components of the double-gear sliding collet-drive assembly of  FIG. 13A  in the pinched configuration. 
         FIG. 14A  is an isometric view of a double-gear sliding collet-drive system with a reset mechanism. 
         FIG. 14B  is a bottom view of the double-gear sliding collet-drive system with a reset mechanism of  FIG. 14A . 
         FIG. 14C . 1  is a top view with some critical components visible of the double-gear sliding collet-drive system with a reset mechanism of  FIG. 14A  with the collet locking. 
         FIG. 14C . 2  is a top view with some critical components visible of the double-gear sliding collet-drive system with a reset mechanism of  FIG. 14A  with the EMD advancing. 
         FIG. 14C . 3  is a top view with some critical components visible of the double-gear sliding collet-drive system with a reset mechanism of  FIG. 14A  with the collet unlocking. 
         FIG. 14C . 4  is a top view with some critical components visible of the double-gear sliding collet-drive system with a reset mechanism of  FIG. 14A  with the EMD retracting. 
         FIG. 15A  is an isometric view of a system that includes a bellows drive. 
         FIG. 15B  is a zoomed-in isometric view of the drive blocks of  FIG. 15A  in an open configuration. 
         FIG. 15C  is a zoomed-in isometric view of the drive blocks of  FIG. 15A  in a closed configuration. 
         FIG. 15D  is a cross-sectional view of the device retainer of  FIG. 15A  in an open configuration. 
         FIG. 15E  is a cross-sectional view of the device retainer of  FIG. 15A  in a closed configuration. 
         FIG. 15F  is a zoomed-in isometric view of the holding blocks of  FIG. 15A  in an open configuration. 
         FIG. 15G  is a zoomed-in isometric view of the holding blocks of  FIG. 15A  in a drive configuration. 
         FIG. 15H  is a zoomed-in isometric view of the holding blocks of  FIG. 15A  in a pinched configuration. 
         FIG. 16A  is an isometric exploded view of a compression-collet system. 
         FIG. 16B  is an isometric assembled view of the compression-collet system of  FIG. 16A . 
         FIG. 16C  is a cross-sectional view showing the compression-collet system of  FIG. 16A  in an unloaded configuration. 
         FIG. 16D  is a cross-sectional view showing the compression-collet system of  FIG. 16A  in a loaded configuration. 
         FIG. 17A  is an isometric view (with phantom lines) of a plunger collet system. 
         FIG. 17B  is a longitudinal cross-sectional view of the plunger collet system of  FIG. 17A  taken generally along lines  17 A. 1 - 17 A. 1  in  FIG. 17A  in the unpinched configuration. 
         FIG. 17C  is a longitudinal cross-sectional view of the plunger collet system of  FIG. 17A  taken generally along lines  17 A. 1 - 17 A. 1  in  FIG. 17A  in the pinched configuration. 
         FIG. 18A  is an isometric exploded assembly view of a plunger collet system with a circular disk housing. 
         FIG. 18B  is an isometric view of a multi-plunger collet system. 
         FIG. 18C  is an isometric view of a multi-plunger collet system with a single plunger collet assembly removed. 
         FIG. 18D  is a side view of a multi-plunger collet system with phantom lines taken generally along lines  18 D- 18 D in  FIG. 18B . 
         FIG. 18E  is longitudinal cross-sectional view of a multi-plunger collet in an unpinched configuration taken generally along lines  18 E- 18 E in  FIG. 18D . 
         FIG. 18F  is longitudinal cross-sectional view of a multi-plunger collet in a pinched configuration taken generally along lines  18 E- 18 E in  FIG. 18D . 
         FIG. 18G  is an isometric view of a multi-plunger collet system with six plungers oriented in the same direction and side and front views of an EMD in the pinched configuration. 
         FIG. 18H  is an isometric view of a multi-plunger collet system with six plungers alternately oriented 180 degrees apart and side and front views of an EMD in the pinched configuration. 
         FIG. 18I  is an isometric view of a multi-plunger collet system with six plungers progressively rotated 60 degrees apart and side and front views of an EMD in the pinched configuration. 
         FIG. 19A  is an isometric view of an opposing pad collet having an inner housing and an outer housing. 
         FIG. 19B  is a side cross-sectional view of an opposing pad collet in an unpinched configuration taken generally along lines  19 B- 19 B in  FIG. 19A . 
         FIG. 19C  is a side cross-sectional view of an opposing pad collet in a pinched configuration taken generally along lines  19 B- 19 B in  FIG. 19A . 
         FIG. 19D  is cross section and end view of the collet of  FIG. 19A  in a first position. 
         FIG. 19E  is cross section and end view of the collet of  FIG. 19A  in a second position. 
         FIG. 19F  is cross section and end view of the collet of  FIG. 19A  in a third position. 
         FIG. 19G  is cross section and end view of the collet of  FIG. 19A  in a fourth position. 
         FIG. 20A  is an isometric view of a collet-drive system with two drive modules. 
         FIG. 20B  is a side view of a first drive module of a collet-drive system with two drive modules of  FIG. 20A  showing some internal components. 
         FIG. 20C  is a plan view of a collet-drive system with two drive modules of  FIG. 20A  in a driving state. 
         FIG. 20D  is a plan view of a collet-drive system with two drive modules of  FIG. 20A  in a collet lock state. 
         FIG. 20E  is a plan view of a collet-drive system with two drive modules of  FIG. 20A  in a device exchange state. 
         FIG. 20F  is a plan view of a collet-drive system with two drive modules of  FIG. 20A  in a state with collet pinched and tires gripped. 
         FIG. 20G  is a plan view of a collet-drive system with two drive modules of  FIG. 20A  in a tire driving state. 
         FIG. 21A  is a plan view of a collet-drive system with EMD support. 
         FIG. 21B  is a plan view of a collet-drive system with EMD support of  FIG. 21A  with a clamp. 
         FIG. 21C  is a plan view of a collet-drive system with EMD support of  FIG. 21A  with a proximal tires. 
         FIG. 21D  is a plan view of a collet-drive system with EMD support of  FIG. 21A  with a distal tires. 
         FIG. 22A  is right isometric view of a drive mechanism for actuating a pair of tires. 
         FIG. 22B  is an exploded view of the drive mechanism of  FIG. 22A   
         FIG. 22C  is a left plan view of the drive mechanism of  FIG. 22A  with the tires in a neutral position. 
         FIG. 22D  a left plan view of the drive mechanism of  FIG. 22A  with the tires in a second position. 
         FIG. 22E  is a left plan view of the drive mechanism of  FIG. 22A  with a housing for the tires. 
         FIG. 22F  is a left isometric view of the drive mechanism of  FIG. 22A  with the offset mechanism in a first configuration. 
         FIG. 22G  is a top plan view of the mechanism from  FIG. 22F  with the engagement cam in an unclamped position and the tires in an engaged position. 
         FIG. 22H  is a top plan view of the mechanism from  FIG. 22F  with the engagement cam in a clamped position and the tires in an engaged position. 
         FIG. 22I  is a top plan view of the mechanism from  FIG. 22F  with the engagement cam in a clamped position and the tires in a disengaged position. 
         FIG. 22J  is a top plan view of the mechanism from  FIG. 22F  with the engagement cam in an unclamped position and the tires in a disengaged position. 
         FIG. 22K  is a schematic view of the eccentric assembly with the first tire assembly and second tire assembly gripping the EMD. 
         FIG. 22L  is a schematic view of the eccentric assembly with the first tire assembly and second tire assembly not gripping the EMD. 
         FIG. 22M  is an isometric view of the tire assemblies being installed onto couplers. 
         FIG. 22N  is a cross sectional view of the tire assemblies and couplers. 
         FIG. 22O  is a partial cross-sectional view of the tire assemblies and eccentric assembly. 
         FIG. 22P  is a schematic cross-sectional view of the tire assemblies having a conical shape. 
         FIG. 22Q  is a schematic cross-sectional view of the tire assemblies having a conical shape in an engaged position. 
         FIG. 22R  is a front view of the tire assemblies being secured to the couplers with an installation member. 
         FIG. 22S  is a front view of the tire assemblies with one tire assembly being removed from the coupler. 
         FIG. 22T  is a close-up of one tire assembly being removed from the coupler. 
         FIG. 22U  is a close-up isometric view of the tire assemblies. 
         FIG. 22V  is a schematic cross sectional view of the tire assemblies and EMD in a first position. 
         FIG. 22W  is a schematic cross sectional view of the tire assemblies and EMD in a second position. 
         FIG. 22X  is a schematic cross sectional view of the tire assemblies and EMD in a third position. 
     
    
    
     DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS 
       FIG. 1  is a perspective view of an exemplary catheter-based procedure system  10  in accordance with an embodiment. Catheter-based procedure system  10  may be used to perform catheter-based medical procedures, e.g., percutaneous intervention procedures such as a percutaneous coronary intervention (PCI) (e.g., to treat STEMI), a neurovascular interventional procedure (NVI) (e.g., to treat an emergent large vessel occlusion (ELVO)), peripheral vascular intervention procedures (PVI) (e.g., for critical limb ischemia (CLI), etc.). Catheter-based medical procedures may include diagnostic catheterization procedures during which one or more catheters or other elongated medical devices (EMDs) are used to aid in the diagnosis of a patient&#39;s disease. For example, during one embodiment of a catheter-based diagnostic procedure, a contrast media is injected onto one or more arteries through a catheter and an image of the patient&#39;s vasculature is taken. Catheter-based medical procedures may also include catheter-based therapeutic procedures (e.g., angioplasty, stent placement, treatment of peripheral vascular disease, clot removal, arterial venous malformation therapy, treatment of aneurysm, etc.) during which a catheter (or other EMD) is used to treat a disease. Therapeutic procedures may be enhanced by the inclusion of adjunct devices  54  (shown in  FIG. 2 ) such as, for example, intravascular ultrasound (IVUS), optical coherence tomography (OCT), fractional flow reserve (FFR), etc. It should be noted, however, that one skilled in the art would recognize that certain specific percutaneous intervention devices or components (e.g., type of guidewire, type of catheter, etc.) may be selected based on the type of procedure that is to be performed. Catheter-based procedure system  10  can perform any number of catheter-based medical procedures with minor adjustments to accommodate the specific percutaneous intervention devices to be used in the procedure. 
     Catheter-based procedure system  10  includes, among other elements, a bedside unit  20  and a control station  26 . Bedside unit  20  includes a robotic drive  24  and a positioning system  22  that are located adjacent to a patient  12 . Patient  12  is supported on a patient table  18 . The positioning system  22  is used to position and support the robotic drive  24 . The positioning system  22  may be, for example, a robotic arm, an articulated arm, a holder, etc. The positioning system  22  may be attached at one end to, for example, a rail on the patient table  18 , a base, or a cart. The other end of the positioning system  22  is attached to the robotic drive  24 . The positioning system  22  may be moved out of the way (along with the robotic drive  24 ) to allow for the patient  12  to be placed on the patient table  18 . Once the patient  12  is positioned on the patient table  18 , the positioning system  22  may be used to situate or position the robotic drive  24  relative to the patient  12  for the procedure. In an embodiment, patient table  18  is operably supported by a pedestal  17 , which is secured to the floor and/or earth. Patient table  18  is able to move with multiple degrees of freedom, for example, roll, pitch, and yaw, relative to the pedestal  17 . Bedside unit  20  may also include controls and displays  46  (shown in  FIG. 2 ). For example, controls and displays may be located on a housing of the robotic drive  24 . 
     Generally, the robotic drive  24  may be equipped with the appropriate percutaneous interventional devices and accessories  48  (shown in  FIG. 2 ) (e.g., guidewires, various types of catheters including balloon catheters, stent delivery systems, stent retrievers, embolization coils, liquid embolics, aspiration pumps, device to deliver contrast media, medicine, hemostasis valve adapters, syringes, stopcocks, inflation device, etc.) to allow the user or operator  11  to perform a catheter-based medical procedure via a robotic system by operating various controls such as the controls and inputs located at the control station  26 . Bedside unit  20 , and in particular robotic drive  24 , may include any number and/or combination of components to provide bedside unit  20  with the functionality described herein. A user or operator  11  at control station  26  is referred to as the control station user or control station operator and referred to herein as user or operator. A user or operator at bedside unit  20  is referred to as bedside unit user or bedside unit operator. The robotic drive  24  includes a plurality of device modules  32   a - d  mounted to a rail or linear member  60  (shown in  FIG. 3 ). The rail or linear member  60  guides and supports the device modules. Each of the device modules  32   a - d  may be used to drive an EMD such as a catheter or guidewire. For example, the robotic drive  24  may be used to automatically feed a guidewire into a diagnostic catheter and into a guide catheter in an artery of the patient  12 . One or more devices, such as an EMD, enter the body (e.g., a vessel) of the patient  12  at an insertion point  16  via, for example, an introducer sheath. 
     Bedside unit  20  is in communication with control station  26 , allowing signals generated by the user inputs of control station  26  to be transmitted wirelessly or via hardwire to bedside unit  20  to control various functions of bedside unit  20 . As discussed below, control station  26  may include a control computing system  34  (shown in  FIG. 2 ) or be coupled to the bedside unit  20  through a control computing system  34 . Bedside unit  20  may also provide feedback signals (e.g., loads, speeds, operating conditions, warning signals, error codes, etc.) to control station  26 , control computing system  34  (shown in  FIG. 2 ), or both. Communication between the control computing system  34  and various components of the catheter-based procedure system  10  may be provided via a communication link that may be a wireless connection, cable connections, or any other means capable of allowing communication to occur between components. Control station  26  or other similar control system may be located either at a local site (e.g., local control station  38  shown in  FIG. 2 ) or at a remote site (e.g., remote control station and computer system  42  shown in  FIG. 2 ). Catheter procedure system  10  may be operated by a control station at the local site, a control station at a remote site, or both the local control station and the remote control station at the same time. At a local site, user or operator  11  and control station  26  are located in the same room or an adjacent room to the patient  12  and bedside unit  20 . As used herein, a local site is the location of the bedside unit  20  and a patient  12  or subject (e.g., animal or cadaver) and the remote site is the location of a user or operator  11  and a control station  26  used to control the bedside unit  20  remotely. A control station  26  (and a control computing system) at a remote site and the bedside unit  20  and/or a control computing system at a local site may be in communication using communication systems and services  36  (shown in  FIG. 2 ), for example, through the Internet. In an embodiment, the remote site and the local (patient) site are away from one another, for example, in different rooms in the same building, different buildings in the same city, different cities, or other different locations where the remote site does not have physical access to the bedside unit  20  and/or patient  12  at the local site. 
     Control station  26  generally includes one or more input modules  28  configured to receive user inputs to operate various components or systems of catheter-based procedure system  10 . In the embodiment shown, control station  26  allows the user or operator  11  to control bedside unit  20  to perform a catheter-based medical procedure. For example, input modules  28  may be configured to cause bedside unit  20  to perform various tasks using percutaneous intervention devices (e.g., EMDs) interfaced with the robotic drive  24  (e.g., to advance, retract, or rotate a guidewire, advance, retract or rotate a catheter, inflate or deflate a balloon located on a catheter, position and/or deploy a stent, position and/or deploy a stent retriever, position and/or deploy a coil, inject contrast media into a catheter, inject liquid embolics into a catheter, inject medicine or saline into a catheter, aspirate on a catheter, or to perform any other function that may be performed as part of a catheter-based medical procedure). Robotic drive  24  includes various drive mechanisms to cause movement (e.g., axial and rotational movement) of the components of the bedside unit  20  including the percutaneous intervention devices. 
     In one embodiment, input modules  28  may include one or more touch screens, joysticks, scroll wheels, and/or buttons. In addition to input modules  28 , the control station  26  may use additional user controls  44  (shown in  FIG. 2 ) such as foot switches and microphones for voice commands, etc. Input modules  28  may be configured to advance, retract, or rotate various components and percutaneous intervention devices such as, for example, a guidewire, and one or more catheters or microcatheters. Buttons may include, for example, an emergency stop button, a multiplier button, device selection buttons and automated move buttons. When an emergency stop button is pushed, the power (e.g., electrical power) is shut off or removed to bedside unit  20 . When in a speed control mode, a multiplier button acts to increase or decrease the speed at which the associated component is moved in response to a manipulation of input modules  28 . When in a position control mode, a multiplier button changes the mapping between input distance and the output commanded distance. Device selection buttons allow the user or operator  11  to select which of the percutaneous intervention devices loaded into the robotic drive  24  are controlled by input modules  28 . Automated move buttons are used to enable algorithmic movements that the catheter-based procedure system  10  may perform on a percutaneous intervention device without direct command from the user or operator  11 . In one embodiment, input modules  28  may include one or more controls or icons (not shown) displayed on a touch screen (that may or may not be part of a display  30 ), that, when activated, causes operation of a component of the catheter-based procedure system  10 . Input modules  28  may also include a balloon or stent control that is configured to inflate or deflate a balloon and/or deploy a stent. Each of the input modules  28  may include one or more buttons, scroll wheels, joysticks, touch screen, etc. that may be used to control the particular component or components to which the control is dedicated. In addition, one or more touch screens may display one or more icons (not shown) related to various portions of input modules  28  or to various components of catheter-based procedure system  10 . 
     Control station  26  may include a display  30 . In other embodiments, the control station  26  may include two or more displays  30 . Display  30  may be configured to display information or patient specific data to the user or operator  11  located at control station  26 . For example, display  30  may be configured to display image data (e.g., X-ray images, MRI images, CT images, ultrasound images, etc.), hemodynamic data (e.g., blood pressure, heart rate, etc.), patient record information (e.g., medical history, age, weight, etc.), lesion or treatment assessment data (e.g., IVUS, OCT, FFR, etc.). In addition, display  30  may be configured to display procedure specific information (e.g., procedural checklist, recommendations, duration of procedure, catheter or guidewire position, volume of medicine or contrast agent delivered, etc.). Further, display  30  may be configured to display information to provide the functionalities associated with control computing system  34  (shown in  FIG. 2 ). Display  30  may include touch screen capabilities to provide some of the user input capabilities of the system. 
     Catheter-based procedure system  10  also includes an imaging system  14 . Imaging system  14  may be any medical imaging system that may be used in conjunction with a catheter based medical procedure (e.g., non-digital X-ray, digital X-ray, CT, MRI, ultrasound, etc.). In an exemplary embodiment, imaging system  14  is a digital X-ray imaging device that is in communication with control station  26 . In one embodiment, imaging system  14  may include a C-arm (shown in  FIG. 1 ) that allows imaging system  14  to partially or completely rotate around patient  12  in order to obtain images at different angular positions relative to patient  12  (e.g., sagittal views, caudal views, anterior-posterior views, etc.). In one embodiment imaging system  14  is a fluoroscopy system including a C-arm having an X-ray source  13  and a detector  15 , also known as an image intensifier. 
     Imaging system  14  may be configured to take X-ray images of the appropriate area of patient  12  during a procedure. For example, imaging system  14  may be configured to take one or more X-ray images of the head to diagnose a neurovascular condition. Imaging system  14  may also be configured to take one or more X-ray images (e.g., real time images) during a catheter-based medical procedure to assist the user or operator  11  of control station  26  to properly position a guidewire, guide catheter, microcatheter, stent retriever, coil, stent, balloon, etc. during the procedure. The image or images may be displayed on display  30 . For example, images may be displayed on display  30  to allow the user or operator  11  to accurately move a guide catheter or guidewire into the proper position. 
     In order to clarify directions, a rectangular coordinate system is introduced with X, Y, and Z axes. The positive X axis is oriented in a longitudinal (axial) distal direction, that is, in the direction from the proximal end to the distal end, stated another way from the proximal to distal direction. The Y and Z axes are in a transverse plane to the X axis, with the positive Z axis oriented up, that is, in the direction opposite of gravity, and the Y axis is automatically determined by right-hand rule. 
       FIG. 2  is a block diagram of catheter-based procedure system  10  in accordance with an exemplary embodiment. Catheter-procedure system  10  may include a control computing system  34 . Control computing system  34  may physically be, for example, part of control station  26  (shown in  FIG. 1 ). Control computing system  34  may generally be an electronic control unit suitable to provide catheter-based procedure system  10  with the various functionalities described herein. For example, control computing system  34  may be an embedded system, a dedicated circuit, a general-purpose system programmed with the functionality described herein, etc. Control computing system  34  is in communication with bedside unit  20 , communications systems and services  36  (e.g., Internet, firewalls, cloud services, session managers, a hospital network, etc.), a local control station  38 , additional communications systems  40  (e.g., a telepresence system), a remote control station and computing system  42 , and patient sensors  56  (e.g., electrocardiogram (ECG) devices, electroencephalogram (EEG) devices, blood pressure monitors, temperature monitors, heart rate monitors, respiratory monitors, etc.). The control computing system is also in communication with imaging system  14 , patient table  18 , additional medical systems  50 , contrast injection systems  52  and adjunct devices  54  (e.g., IVUS, OCT, FFR, etc.). The bedside unit  20  includes a robotic drive  24 , a positioning system  22  and may include additional controls and displays  46 . As mentioned above, the additional controls and displays may be located on a housing of the robotic drive  24 . Interventional devices and accessories  48  (e.g., guidewires, catheters, etc.) interface to the bedside system  20 . In an embodiment, interventional devices and accessories  48  may include specialized devices (e.g., IVUS catheter, OCT catheter, FFR wire, diagnostic catheter for contrast, etc.) which interface to their respective adjunct devices  54 , namely, an IVUS system, an OCT system, and FFR system, etc. 
     In various embodiments, control computing system  34  is configured to generate control signals based on the user&#39;s interaction with input modules  28  (e.g., of a control station  26  (shown in  FIG. 1 ) such as a local control station  38  or a remote control station  42 ) and/or based on information accessible to control computing system  34  such that a medical procedure may be performed using catheter-based procedure system  10 . The local control station  38  includes one or more displays  30 , one or more input modules  28 , and additional user controls  44 . The remote control station and computing system  42  may include similar components to the local control station  38 . The remote  42  and local  38  control stations can be different and tailored based on their required functionalities. The additional user controls  44  may include, for example, one or more foot input controls. The foot input control may be configured to allow the user to select functions of the imaging system  14  such as turning on and off the X-ray and scrolling through different stored images. In another embodiment, a foot input device may be configured to allow the user to select which devices are mapped to scroll wheels included in input modules  28 . Additional communication systems  40  (e.g., audio conference, video conference, telepresence, etc.) may be employed to help the operator interact with the patient, medical staff (e.g., angio-suite staff), and/or equipment in the vicinity of the bedside. 
     Catheter-based procedure system  10  may be connected or configured to include any other systems and/or devices not explicitly shown. For example, catheter-based procedure system  10  may include image processing engines, data storage and archive systems, automatic balloon and/or stent inflation systems, medicine injection systems, medicine tracking and/or logging systems, user logs, encryption systems, systems to restrict access or use of catheter-based procedure system  10 , etc. 
     As mentioned, control computing system  34  is in communication with bedside unit  20  which includes a robotic drive  24 , a positioning system  22  and may include additional controls and displays  46 , and may provide control signals to the bedside unit  20  to control the operation of the motors and drive mechanisms used to drive the percutaneous intervention devices (e.g., guidewire, catheter, etc.). The various drive mechanisms may be provided as part of a robotic drive  24 .  FIG. 3  is a perspective view of a robotic drive for a catheter-based procedure system  10  in accordance with an embodiment. In  FIG. 3 , a robotic drive  24  includes multiple device modules  32   a - d  coupled to a linear member  60 . Each device module  32   a - d  is coupled to the linear member  60  via a stage  62   a - d  moveably mounted to the linear member  60 . A device module  32   a - d  may be connected to a stage  62   a - d  using a connector such as an offset bracket  78   a - d . In another embodiment, the device module  32   a - d  is directly mounted to the stage  62   a - d . Each stage  62   a - d  may be independently actuated to move linearly along the linear member  60 . Accordingly, each stage  62   a - d  (and the corresponding device module  32   a - d  coupled to the stage  62   a - d ) may independently move relative to each other and the linear member  60 . A drive mechanism is used to actuate each stage  62   a - d . In the embodiment shown in  FIG. 3 , the drive mechanism includes independent stage translation motors  64   a - d  coupled to each stage  62   a - d  and a stage drive mechanism  76 , for example, a lead screw via a rotating nut, a rack via a pinion, a belt via a pinion or pulley, a chain via a sprocket, or the stage translation motors  64   a - d  may be linear motors themselves. In some embodiments, the stage drive mechanism  76  may be a combination of these mechanisms, for example, each stage  62   a - d  could employ a different type of stage drive mechanism. In an embodiment where the stage drive mechanism is a lead screw and rotating nut, the lead screw may be rotated and each stage  62   a - d  may engage and disengage from the lead screw to move, e.g., to advance or retract. In the embodiment shown in  FIG. 3 , the stages  62   a - d  and device modules  32   a - d  are in a serial drive configuration. 
     Each device module  32   a - d  includes a drive module  68   a - d  and a cassette  66   a - d  mounted on and coupled to the drive module  68   a - d . In the embodiment shown in  FIG. 3 , each cassette  66   a - d  is mounted to the drive module  68   a - d  in a vertical orientation. In other embodiments, each cassette  66   a - d  may be mounted to the drive module  68   a - d  in other mounting orientations. Each cassette  66   a - d  is configured to interface with and support a proximal portion of an EMD (not shown). In addition, each cassette  66   a - d  may include elements to provide one or more degrees of freedom in addition to the linear motion provided by the actuation of the corresponding stage  62   a - d  to move linearly along the linear member  60 . For example, the cassette  66   a - d  may include elements that may be used to rotate the EMD when the cassette is coupled to the drive module  68   a - d . Each drive module  68   a - d  includes at least one coupler to provide a drive interface to the mechanisms in each cassette  66   a - d  to provide the additional degree of freedom. Each cassette  66   a - d  also includes a channel in which a device support  79   a - d  is positioned, and each device support  79   a - d  is used to prevent an EMD from buckling. A support arm  77   a ,  77   b , and  77   c  is attached to each device module  32   a ,  32   b , and  32   c , respectively, to provide a fixed point for support of a proximal end of the device supports  79   b ,  79   c , and  79   d , respectively. The robotic drive  24  may also include a device support connection  72  connected to a device support  79 , a distal support arm  70  and a support arm  77   o . Support arm  77   o  is used to provide a fixed point for support of the proximal end of the distal most device support  79   a  housed in the distal most device module  32   a . In addition, an introducer interface support (redirector)  74  may be connected to the device support connection  72  and an EMD (e.g., an introducer sheath). The configuration of robotic drive  24  has the benefit of reducing volume and weight of the drive robotic drive  24  by using actuators on a single linear member. 
     To prevent contaminating the patient with pathogens, healthcare staff use aseptic technique in a room housing the bedside unit  20  and the patient  12  or subject (shown in  FIG. 1 ). A room housing the bedside unit  20  and patient  12  may be, for example, a cath lab or an angio suite. Aseptic technique consists of using sterile barriers, sterile equipment, proper patient preparation, environmental controls and contact guidelines. Accordingly, all EMDs and interventional accessories are sterilized and can only be in contact with either sterile barriers or sterile equipment. In an embodiment, a sterile drape (not shown) is placed over the non-sterile robotic drive  24 . Each cassette  66   a - d  is sterilized and acts as a sterile interface between the draped robotic drive  24  and at least one EMD. Each cassette  66   a - d  can be designed to be sterile for single use or to be re-sterilized in whole or part so that the cassette  66   a - d  or its components can be used in multiple procedures. 
     Distal and Proximal: The terms distal and proximal define relative locations of two different features. With respect to a robotic drive the terms distal and proximal are defined by the position of the robotic drive in its intended use relative to a patient. When used to define a relative position, the distal feature is the feature of the robotic drive that is closer to the patient than a proximal feature when the robotic drive is in its intended in-use position. Within a patient, any vasculature landmark further away along the path from the access point is considered more distal than a landmark closer to the access point, where the access point is the point at which the EMD enters the patient. Similarly, the proximal feature is the feature that is farther from the patient than the distal feature when the robotic drive in its intended in-use position. When used to define direction, the distal direction refers to a path on which something is moving or is aimed to move or along which something is pointing or facing from a proximal feature toward a distal feature and/or patient when the robotic drive is in its intended in-use position. The proximal direction is the opposite direction of the distal direction. By way of examples referring to  FIG. 1 , a robotic device is shown from the viewpoint of an operator facing a patient. In this arrangement, the distal direction is along the positive X coordinate axis and the proximal direction is along the negative X coordinate axis. Referring to  FIG. 3 , the EMD is moved in a distal direction on a path toward a patient through the introducer interface support  74  which defines the distal end of the robotic drive  24 . The proximal end of the robotic drive  24  is the point furthest from the distal end along the negative X axis. Referring to  FIG. 3 , the most distal drive module is the drive module  32   a  closest to the distal end of the robotic drive  24 . The most proximal drive module is the drive module  32   d  positioned furthest from the distal end of the robotic drive  24  along the negative X axis. The relative position of drive modules is determined by their relative location to the distal end of the robotic drive. For example, drive module  32   b  is distal to drive module  32   c . Referring to  FIG. 3 , the portions of cassette  66   a  and drive module  68   a  are defined by their relative location to the distal end of the robotic drive. For example, the distal end of cassette  66   a  is the portion of the cassette that is closest to the distal end of the robotic drive and the proximal end of cassette  66   a  is the portion of the cassette that is furthest from the distal end of the robotic drive along the negative X axis when the cassette is in-use position on drive module  68   a . Stated in another way, the distal end of cassette  66   a  is the portion of the cassette through which an EMD is closest to the path leading to a patient in the in-use position. 
     Longitudinal axis: The term longitudinal axis of a member (for example, an EMD or other element in the catheter-based procedure system) is the line or axis along the length of the member that passes through the center of the transverse cross section of the member in the direction from a proximal portion of the member to a distal portion of the member. For example, the longitudinal axis of a guidewire is the central axis in the direction from a proximal portion of the guidewire toward a distal portion of the guidewire even though the guidewire may be non-linear in the relevant portion. 
     Axial Movement: The term axial movement of a member refers to translation of the member along the longitudinal axis of the member. When the distal end of an EMD is axially moved in a distal direction along its longitudinal axis into or further into the patient, the EMD is being advanced. When the distal end of an EMD is axially moved in a proximal direction along its longitudinal axis out of or further out of the patient, the EMD is being withdrawn. 
     Rotational Movement: The term rotational movement of a member refers to the change in angular orientation of the member about the local longitudinal axis of the member. Rotational movement of an EMD corresponds to clockwise or counterclockwise rotation of the EMD about its longitudinal axis due to an applied torque. 
     Axial and Lateral Insertion: The term axial insertion refers to inserting a first member into a second member along the longitudinal axis of the second member. An EMD that is axially loaded in a collet is axially inserted in the collet. An example of axial insertion could be referred to as back loading a catheter on the proximal end of a guidewire. The term lateral insertion refers to inserting a first member into a second member along a direction in a plane perpendicular to the longitudinal axis of the second member. This can also be referred to as radial loading or side loading. Stated another way, lateral insertion refers to inserting a first member into a second member along a direction that is parallel to the radius and perpendicular to the longitudinal axis of the second member. 
     Pinch/Unpinch: The term pinch refers to releasably fixing an EMD to a member such that the EMD and member move together when the member moves. The term unpinch refers to releasing the EMD from a member such that the EMD and member move independently when the member moves. 
     Clamp/Unclamp: The term clamp refers to releasably fixing an EMD to a member such that the EMD&#39;s movement is constrained with respect to the member. The member can be fixed with respect to a global coordinate system or with respect to a local coordinate system. The term unclamp refers to releasing the EMD from the member such that the EMD can move independently. 
     Grip/Ungrip: The term grip refers to the application of a force or torque to an EMD by a drive mechanism that causes motion of the EMD without slip in at least one degree of freedom. The term ungrip refers to the release of the application of the force or torque to the EMD by a drive mechanism such that the position of the EMD is no longer constrained. In one example an EMD is gripped between two tires rotates about its longitudinal axis when the tires move longitudinally relative to one another. The rotational movement of the EMD is different than the movement of the two tires. The position of an EMD that is gripped is constrained by the drive mechanism. 
     Buckling: The term buckling refers to the tendency of a flexible EMD when under axial compression to bend away from the longitudinal axis or intended path along which it is being advanced. In one embodiment axial compression occurs in response to resistance from being navigated in the vasculature. The distance an EMD may be driven along its longitudinal axis without support before the EMD buckles is referred to herein as the device buckling distance. The device buckling distance is a function of the device&#39;s stiffness, geometry (including but not limited to diameter), and force being applied to the EMD. Buckling may cause the EMD to form an arcuate portion different than the intended path. Kinking is a case of buckling in which deformation of the EMD is non-elastic resulting in a permanent set. 
     Homing: The term homing refers to moving a member to a defined position. An example of a defined position is a reference position. Another example of a defined position is an initial position. The term home refers to the defined position. It is normally used as a reference for subsequent linear or rotational positions. 
     Up/Down; Front/Rear; Inwardly/Outwardly: The terms top, up, and upper refer to the general direction away from the direction of gravity and the terms bottom, down, and lower refer to the general direction in the direction of gravity. The term front refers to the side of the robotic drive that faces a bedside user and away from the positioning system, such as the articulating arm. The term rear refers to the side of the robotic drive that is closest to the positioning system, such as the articulating arm. The term inwardly refers to the inner portion of a feature. The term outwardly refers to the outer portion of a feature. 
     Stage: The term stage refers to a member, feature, or device that is used to couple a device module to the robotic drive. For example, the stage may be used to couple the device module to a rail or linear member of the robotic drive. 
     Drive Module: The term drive module generally refers to the part (e.g., the capital part) of the robotic drive system that normally contains one or more motors with drive couplers that interface with the cassette. 
     Device Module: The term device module refers to the combination of a drive module and a cassette. 
     Cassette The term cassette generally refers to the part (non-capital, consumable or sterilizable unit) of the robotic drive system that normally is the sterile interface between a drive module and at least one EMD (directly) or through a device adapter (indirectly). 
     Collet: The term collet refers to a device that can releasably fix a portion of an EMD. The term fixed here means no intentional relative movement of the collet and EMD during operation. In one embodiment the collet includes at least two members that move rotationally relative to each other to releasably fix the EMD to at least one of the two members. In one embodiment the collet includes at least two members that move axially (along a longitudinal axis) relative to each other to releasably fix the EMD to at least one of the two members. In one embodiment the collet includes at least two members that move rotationally and axially relative to each other to releasably fix the EMD to at least one of the two members. 
     Fixed: The term fixed means no intentional relative movement of a first member with respect to a second member during operation. 
     On-Device Adapter: The term on-device adapter refers to a sterile apparatus capable of releasably pinching an EMD to provide a driving interface. The on-device adapter is also known as an end-effector or EMD capturing device. In one non-limiting embodiment the on-device adapter is a collet that is operatively controlled robotically to rotate the EMD about its longitudinal axis, to pinch and/or unpinch the EMD to the collet, and/or to translate the EMD along its longitudinal axis. In one embodiment the on-device adapter is a hub-drive mechanism such as a driven gear located on the hub of an EMD. 
     Tandem Drive: The term tandem drive refers to a drive unit or subsystem within the robotic drive containing two or more EMD drive modules, capable of manipulating one or more EMDs. 
     EMD: The term elongated medical device (EMD) refers to, but is not limited to, catheters (e.g., guide catheters, microcatheters, balloon/stent catheters), wire-based devices (e.g., guidewires, embolization coils, stent retrievers, etc.), and medical devices comprising any combination of these. In one example a wire-based EMD includes but is not limited to guidewires, microwires, a proximal pusher for embolization coils, stent retrievers, self-expanding stents, and flow divertors. Typically wire-based EMD&#39;s do not have a hub or handle at its proximal terminal end. In one embodiment the EMD is a catheter having a hub at a proximal end of the catheter and a flexible shaft extending from the hub toward the distal end of the catheter, wherein the shaft is more flexible than the hub. In one embodiment the catheter includes an intermediary portion that transitions between the hub and the shaft that has an intermediate flexibility that is less rigid than the hub and more rigid than the shaft. In one embodiment the intermediary portion is a strain relief. 
     Hub (Proximal) Driving: The term hub driving or proximal driving refers to holding on to and manipulating an EMD from a proximal position (e.g., a geared adapter on a catheter hub). In one embodiment, hub driving refers to imparting a force or torque to the hub of a catheter to translate and/or rotate the catheter. Hub driving may cause the EMD to buckle and thus hub driving often requires anti-buckling features. For devices that do not have hubs or other interfaces (e.g., a guidewire), device adapters may be added to the device to act as an interface for the device module. In one embodiment, an EMD does not include any mechanism to manipulate features within the catheter such as wires that extend from the handle to the distal end of the catheter to deflect the distal end of the catheter. 
     Shaft (Distal) Driving: The term shaft (distal) driving refers to holding on to and manipulating an EMD along its shaft. In one example the on-device adapter is normally placed just proximal of the hub or Y-connector the device is inserted into. If the location of the on-device adapter is at the proximity of an insertion point (to the body or another catheter or valve), shaft driving does not typically require anti-buckling features. (It may include anti-buckling features to improve drive capability.) 
     Sterilizable Unit: The term sterilizable unit refers to an apparatus that is capable of being sterilized (free from pathogenic microorganisms). This includes, but is not limited to, a cassette, consumable unit, drape, device adapter, and sterilizable drive modules/units (which may include electromechanical components). Sterilizable Units may come into contact with the patient, other sterile devices, or anything else placed within the sterile field of a medical procedure. 
     Sterile Interface: The term sterile interface refers to an interface or boundary between a sterile and non-sterile unit. For example, a cassette may be a sterile interface between the robotic drive and at least one EMD. 
     Reset The term reset means repositioning a drive mechanism from a first position to a second position to allow for continued rotational and/or axial movement of an EMD. During reset, the EMD is not actively being moved by the drive mechanism. In one embodiment the EMD is released by the drive mechanism prior to repositioning the drive mechanism. In one embodiment a clamp fixes the location of the EMD during repositioning of the drive mechanism. 
     Continuous Motion: The term continuous motion refers to motion that does not require a reset and is uninterrupted. 
     Discrete Motion: The term discrete motion refers to motion that requires a reset and is interrupted. 
     Consumable: The term consumable refers to a sterilizable unit that normally has a single use in a medical procedure. The unit could be a reusable consumable through a re-sterilization process for use in another medical procedure. 
     Device Support: The term device support refers to a member, feature, or device that prevents an EMD from buckling. 
     Double Gear: The term double-gear refers to two independently driven gears operatively connected to two different portions of a device. Each of the two gears may be identical or different design. The term gear may be a bevel gear, spiral bevel gear, spur gear, miter gear, worm gear, helical gear, rack and pinon, screw gear, internal gear such as a sun gear, involute spline shafts and bushing, or any other type of gears known in the art. In one example, double-gear also includes devices in which any drive connection is maintained by two different portions of a device, including but not limited to a belt, friction engagement or other couplers known in the art. 
     Referring to  FIG. 3  and  FIG. 4A  an EMD drive system includes an on-device adapter  112  which in one embodiment includes a collet that is removably fixed to an EMD  102 . Collet  112  is a device that releasably fixes a shaft portion of EMD  102  thereto. As described in more detail herein collet  112  pinches the shaft of EMD  102  such that rotation and/or translation of the entire collet  112  about or along its longitudinal axis results in the same rotation and/or translation of the portion of the shaft of EMD  102  that is pinched. In one embodiment collet  112  may be a single molded component having a body defining an internal pathway through which a portion of the shaft of the EMD  102  may be fixed. As described herein the shaft of the EMD  102  is positioned in the internal pathway of the collet and pinched therein. The shaft of the EMD  102  may be radially loaded or axially-loaded into the internal pathway of the collet. Radially loaded may also be referred to as side-loaded or laterally loaded since the shaft of the EMD is loaded into the collet  112  through a longitudinal side of the collet body (that is the side of the collet body extending from a proximal end to the distal end of the collet body). Radially loading, side loading or laterally loading is in contrast to axially loading in which a shaft portion is loaded into the internal pathway by first inserting a free end of the shaft into a proximal or distal opening in the collet&#39;s internal pathway. 
     In one embodiment the collet  112  includes at least two members that move relative to each other to releasably fix the shaft portion of the EMD to at least one of the two members. In one embodiment the two members operating together provide a mechanical advantage that increases the torque and/or force that may be transmitted from the collet body to the shaft of the EMD without the shaft of the EMD moving relative to the collet body. The pinch force on the EMD using a collet can be greater than the force required to actuate the pinch. When the shaft of the EMD is pinched it is fixed such that there is relative movement of the collet and EMD during acceptable operation parameters of an EMD procedure. 
     EMD  102  is fixed to the collet  112  and radially loaded into a robotic drive also referred to herein as a device module  32  such as an EMD drive. An EMD support  79  is removably applied to EMD  102  from a non-axial direction. Robotic drive  32  is operatively coupled to collet  112  to translate and/or rotate collet  112  and EMD  102 . In one embodiment EMD  102  is removably and releasably loaded into the robotic drive  32 . 
     In one embodiment collet  112  is in robotic drive  32  when EMD  102  is radially loaded into robotic drive  32 . In one embodiment collet  112  is removably inserted into robotic drive  32  with EMD  102  fixed to collet  112 . 
     In one embodiment EMD support  79  limits buckling and prevents kinking of EMD  102  along its length as EMD  102  is being translated and/or rotated. 
     In one embodiment a robotic system includes a robotic drive  32  or device module includes a drive module  68  or base having a drive coupler  130 , and a cassette  66  removably secured to the drive module  68 . Collet  112  in cassette  66  is removably fixed to EMD  102 . Collet  112  has a driven member  136  operatively coupled to drive coupler  130 . The robotic drive  32  includes a motor or actuator operatively coupled to collet  112  to move collet  112 . In one embodiment cassette  66  is removably secured to base  68  by directly connecting cassette  66  to base  68 . In one embodiment cassette is 66 is removably secured to base  68  indirectly in which an intermediate member is positioned between cassette  66  and base  68 . 
     EMD  102  may be radial loaded or axially loaded into collet  112  prior to collet  112  being positioned within cassette  66  such that EMD  102  and collet  112  are loaded into cassette  66  together. EMD  102  may be radial loaded or axially loaded into collet  112  or when collet  112  is already positioned within cassette  66 . 
     In one embodiment EMD  102  is removably received in collet  112  in a radial direction and collet  112  is removably received and positioned in cassette  66 . As described herein collet  112  may have a slot extending from an outer periphery of a collet body extending to its internal pathway. A portion of EMD  102  such as a shaft portion may be inserted into the pathway through the slot in a radial direction. The shaft portion of EMD  102  is a portion of the EMD  102  intermediate a proximal end of EMD  102  and a distal end of EMD  102 . Radial loading of the shaft portion of EMD  102  into the collet occurs while the proximal end of EMD  102  and the distal end of EMD  102  remain outside of the collet and pathway. Stated another way shaft portion of EMD  102  is loaded in a direction generally perpendicular to a longitudinal axis of collet  112 . 
     In one embodiment EMD  102  is removably received in collet  112  in an axial direction and collet  112  is removably received in cassette  66 . In this embodiment one of the distal end or proximal end of EMD  102  is inserted into a distal opening or proximal opening collet  112  and moved along the longitudinal axis of collet  112  until the distal end or proximal end of EMD exits the other of the distal end or proximal end of collet. 
     In one embodiment EMD  102  is removably received in collet  112  in a radial direction and collet  112  is non-removably positioned within cassette  66 . In one embodiment EMD  102  is removably received in collet  112  in an axial direction and collet  112  is non-removably positioned within cassette  66 . In one embodiment collet  112  includes a locating feature  408  that is located within cassette  66  with a locating feature  133  that allows for radial loading as well as rotation of the collet within the cassette  66 . In one embodiment collet  112  also includes a distal end that that is located within a locating feature in cassette  66 . 
     Referring to  FIG. 4F  in one embodiment a motor  124  is positioned within base  68  operatively coupled to drive coupler  130 . Drive coupler  130  extends into cassette  66 , when cassette  66  is secured to base  68 . In one embodiment the motor is located in cassette  66 . In one embodiment the motor is located outside of the base  68  but operatively connected to the drive coupler  130  in the base  68 . 
     In one embodiment robotic system includes a clamp releasably clamping a shaft portion of the EMD independent of the collet. In one embodiment the clamp includes at least one tire. 
     As discussed in more detail herein in one embodiment moving collet  112  rotates the collet and EMD. In one embodiment EMD  102  is selectively rotated in a clockwise and counterclockwise direction about a longitudinal axis of EMD  102 . 
     As discussed in more detail herein in one embodiment moving collet  112  selectively pinches and unpinches the EMD within the collet. In one embodiment as discussed in detail herein moving collet  112  includes moving only one or more parts of collet  112  and not the entire collet to pinch and unpinch the EMD. 
     As discussed in more detail herein in one embodiment moving collet  112  selectively translates the collet and EMD in a first direction and opposite second direction along a longitudinal axis of the EMD. 
     As discussed in more detail herein in one embodiment moving collet  112  includes rotating the collet and EMD, translating the collet and EMD and selectively pinching and unpinching the EMD within the collet. 
     Referring to  FIGS. 3, 4G and 4H  robotic system  24  includes a plurality of device modules  32   a - 32   d . In one embodiment there are two or more separate device modules.  FIG. 3  illustrates a system with four device modules  32 . In one embodiment the modules are identical and in one embodiment each device module is different or some modules are identical and some are different.  FIG. 3  as discussed above illustrates a system with four device modules  32 . Each EMD device support  79   a - 79   d  includes a proximal end and a distal end terminating in a distal connector  80 . By way of example, referring to  FIG. 4H , device module  32   c  has an EMD device support  79   c  that has a proximal end  79   c . 1  and an opposing distal end connector  79   c . 2 . Proximal end  79   c . 1  of EMD device support  79   c  is secured to a proximal end  77   b . 1  of arm  77   b . Arm  77   b  has a distal end  77   b . 2  that is secured to device module  32   b  that is distal to device module  32   c . The terminal end  77   b . 2  of EMD drive support device  77   b  is secured to the proximal end of device module  32   b  so that the terminal end  77   b . 2  cannot be moved distal to the distal terminal end of device module  32   b . In operation distal end connector  80   c  is removably connected to a proximal end connector  88   b  on device module  32   b . In one embodiment EMD supports  79   a - 79   d  include a flexible tube having a longitudinal slit permitting an EMD to be inserted into and removed from respective EMD device supports  79   a - 79   d . In one embodiment EMD supports  79   a - 79   d  operates as the flexible track described in US Published Application No. US 2016/0271368 entitled Guide Catheter Control Flexible Track owned by the same applicant as the instant application. Arm  77   b  moves linearly with drive module  32   b  and accordingly, in one mode proximal end  77   c . 1  and distal end  77   c . 2  moves with drive module  32   b  relative to drive module  32   c . EMD device support  79   c  is removably applied to the EMD  102  being manipulated by device module  32   c  in a non-axial direction. The EMD  102  being manipulated by device module  32   c  enters and exits support  79   c  via the longitudinal slit extending from the outer periphery of the EMD device support to the inner lumen of the EMD support. In one embodiment EMD device support is a telescoping member as discussed further herein in which the EMD may be axially loaded or non-axially loaded within the EMD device support to provide anti-buckling support. Referring to  FIG. 3  each drive module  32   a - 32   d  independently manipulates a different device. Each EMD device support  79   a - 79   d  allows each device to be translated a greater distance between two adjacent devices than could be translated without an EMD Support. Without EMD device supports, the distance a device could be translated would be less than the buckling length of the device. Accordingly, the system would need to reset the drive each time the EMD is moved the buckling length. The EMD supports allow for non-reset during use of certain devices in conjunction with each other and/or procedures. Stated another way other words EMD device support allows the collet not to be reset when using certain devices. In one embodiment EMD Supports allow for fewer resets of the collet than would otherwise be necessary without the EMD supports. Referring to  FIG. 4G  device support  79  is guided through cassette  66   c  via a channel  138  and a proximal support member  82  via a channel  84  that extends therethrough. 
     EMD  102  may be pinched by on-device adapter and/or collet  112  by manually manipulating collet  112  and then the collet and EMD are robotically rotated and translated. In one embodiment EMD  102  is robotically pinched and unpinched by collet  112  as well as robotically rotated and translated by rotating and translating collet  112 . 
     A number of robotic EMD drive systems are described herein. Additionally, a number of collet designs are also described herein. The specific collet designs described herein, and collet designs known in the art may be used in the various EMD drive systems described. Collets as described herein may also referred to in the art as a pin vise, chuck, bushing, or guidewire torquer. 
     Referring to  FIGS. 1, 4A and 4D  device module  32  includes a drive module  68  including a drive module base component  116  and a load-sensed component  118 . An EMD  102  is removably coupled to an isolated component  106 . The isolated component  106  is isolated from an external load other than an actual load acting on the EMD  102 . The isolated component  106  is removably coupled to the load-sensed component  118 . A load sensor  120  that is secured to the drive module base component  116  and the load-sensed component  118  senses the actual load acting on the EMD  102 . 
     In one embodiment load sensor  120  is the sole support of the load-sensed component  118  in at least one direction of load measurement. In one embodiment cassette housing  104  and isolated component  106  are internally connected so they form one component. In one embodiment a flexible membrane  108  connects cassette housing  104  and isolated component  106 , where flexible membrane  108  applies negligible forces in the X-direction (device direction) to the isolated component  106 . In one embodiment, flexible membrane  108  is not a physical membrane and represents the cassette interaction. 
     Referring to  FIGS. 4A and 4B  in one embodiment the apparatus includes a cassette  66  that is comprised of a cassette housing  104  removably attached to the drive module base component  116  and a cassette cover  105 . 
     Referring to  FIGS. 5C-5E  in one embodiment the drive module base component  116  includes the load-sensed component  118  and load sensor  120 . Drive module  68  includes drive module base component  116  and load-sensed component  118  as separate parts that are connected by load sensor  120  that is located between drive module base component  116  and load-sensed component  118 . Bearing  128  of load-sensed component  118  supports the load-sensed component in at least one off-axis (non-measured) direction. 
     Referring to  FIGS. 8A and 8B , in one embodiment EMD on-device adapter  112  is connected to a catheter  140 . On-device adapter  112  includes an integrally connected driven bevel gear  136  that can be removably connected to a Y-connector shown with hub  142  that can be removably connected to a hemostasis valve on the proximal end. One embodiment of EMD on-device adapter  112  includes a catheter  140  removably connected to a driven bevel gear  136 . Catheter  140  includes a catheter hub  139  and a catheter shaft  141  that are integrally connected. In one embodiment catheter hub  139  is not a handle that includes mechanisms that manipulate a feature or portion of the catheter. In one embodiment an EMD includes a handle with mechanisms to manipulate features within the catheter such as wires that extend from the handle to the distal end of the catheter to steer or deflect the distal end of the catheter. In contrast the hub is the rigid portion of the EMD at the proximal end that does not include mechanisms to manipulate features within the catheter. 
     Referring to  FIGS. 4B and 4C  the isolated component  106  is positioned within and separate from the cassette housing  104  in at least one direction when the isolated component  106  is connected to the load-sensed component  118 . Isolated component  106  includes a first component  106   a  and a second component  106   b  attached thereto. Referring to  FIGS. 4A-4C  the first component  106   a  is placed within a recess  143  of the cassette housing  104  in a first direction that is defined as the direction toward the drive module  68  when the cassette  66  is in the in-use position secured to the drive module  68 . The second component  106   b  is placed within the recess  143  from a direction away from the load-sensed component  118  toward the first component  106   a . Stated another way referring to  FIG. 4C  first component  106   a  is placed in recess  143  in a −z axis direction from above the cassette housing  104  and the second component  106   b  is placed in recess  143  in a +z axis direction from below the cassette housing  104 . 
     Referring to  FIGS. 4C and 4F  the first component  106   a  and second component  106   b  are secured to one another. Cassette housing  104  includes two longitudinally oriented and spaced parallel rails  107  located within the recess  143 . Rails  107  are also referred to as linear guides herein. Rails  107  are substantially parallel to one another and spaced from one another. The first component  106   a  is located on the top surface of rails  107  closest to the top surface of the cassette housing  104  and the second component  106   b  is located on the bottom surface of rails  107  closest to the load-sensed component  118 . Note that although the direction of assembly of first component  106   a  and second component  106   b  of the isolated component  106  is described in relation to the in-use position, the first and second components of the isolated component  106  are installed away from the drive module  68 . Stated another way, the first component  106   a  of the isolated component  106  is inserted into the recess  143  in a direction from a top surface of the cassette  66  toward the bottom surface of the cassette  66  in a direction generally perpendicular to the longitudinal axis of the cassette housing  104 . 
     In one embodiment a mechanical fastener or plurality of fasteners secure the first component  106   a  to the second component  106   b  of the isolated component  106 . In one embodiment the first component  106   a  and second component  106   b  are secured together using magnets. In one embodiment the first component  106   a  and second component  106   b  of the isolated component  106  are secured with an adhesive. In one embodiment the first component  106   a  and second component  106   b  are releasably secured to one another without the use of tools. In one embodiment the first component  106   a  and second component  106   b  are non-releasably secured to one another. 
     Referring to  FIG. 4F  in an in-use position where the second component  106   b  of the isolated component  106  is releasably secured to the load-sensed component  118 , the first component  106   a  and second component  106   b  are spaced from the rails  107  of the cassette housing  104  such that the first component  106   a  and second component  106   b  are in a non-contact relationship with cassette housing  104 . 
     In one embodiment the on-device adapter  112  is spaced from and in non-contact with the cassette housing  104  when the on-device adapter  112  is coupled to the load-sensed component  118 . In one embodiment the isolated component  106  is separate from the cassette housing  104  in all directions. In one embodiment the isolated component  106  is separate from and in a non-contact relationship with the cassette housing  104 . 
     Referring to  FIGS. 4B, and 4C , in one embodiment the cassette  66  includes a cassette cover  105  pivotably coupled by hinge  103  to the isolated component  106  separate and in non-contact with the cassette housing  104 . In one embodiment the cassette cover  105  is pivotably coupled by hinge  103  to the first component  106   a  of the isolated component  106 . In one embodiment the cassette cover  105  is connected to the first component  106   a  of the isolated component  106  by other means, such as snap fits. 
     Referring to  FIGS. 1 and 4C , in one embodiment the drive module  68  moves the EMD  102  in a first direction, the isolated component  106  being separate from the cassette housing  104  in the first direction. In one embodiment the drive module  68  moves the EMD  102  in a second direction, the isolated component  106  being separate from the cassette housing  104  in the first direction and the second direction. 
     Referring to  FIG. 4D  in one embodiment second component  106   b  of the isolated component  106  is releasably secured to the load-sensed component  118  with fasteners. In one embodiment the fasteners include a quick release mechanism that can releasably secure the second component  106   b  of the isolated component  106  to the load-sensed component  118 . In one embodiment the fasteners are magnets. 
     Referring to  FIGS. 5A-5E -sensed component  118  is located within the drive module base component  116  and secured to the drive module base component  116  with a load sensor  120 . In one embodiment load sensor  120  includes a first portion secured to drive module base component  116  with a first fastener  115  and a second portion secured to load-sensed component  118  with a second fastener  119 . In one embodiment the first portion of the load sensor  120  is different and distinct from the second portion of the load sensor  120 . In one embodiment first fastener  115  and second fastener  119  are bolts. In one embodiment first fastener  115  and second fastener  119  are mechanical fastening components known in the art for ensuring mechanical connection. In one embodiment first fastener  115  and second fastener  119  are replaced with adhesive means for ensuring mechanical connection. In one embodiment first fastener  115  and second fastener  119  are magnets. 
     Referring to  FIG. 5A  in one embodiment drive module base component  116  includes a recess that receives load-sensed component  118 . In one embodiment drive module base component  116  further defines a cavity extending from recess that receives a portion of load sensor  120 . 
     Referring to  FIGS. 4B and 4D  in one embodiment cassette housing  104  is releasably connected to drive module base component  116  via a quick-release mechanism  121 . In one embodiment quick-release mechanism  121  includes a spring-biased member in the cassette housing  104  that is activated by a latch release  123  that releasably engages with a quick release locking pin  117   a  secured to the drive module base component  116 . In one embodiment an alignment pin  117   b  secured to the drive module base component  116  aligns the cassette housing  104  relative to the drive module base component  116 . 
     Referring to  FIGS. 4C and 4F , isolated component  106  is contained inside cassette housing  104  by attaching first component  106   a  to second component  106   b  of isolated component  106  about rails  107  in cassette housing  104 . In the in-use position, isolated component  106  is not in contact with rails  107 . In this way, load interaction due to an external force and/or external torque acting on EMD  102  occurs with one component in the cassette  66 . 
     Cassette housing  104  includes a cradle  132  configured to receive EMD on-device adapter  112  with EMD  102 . A cassette bevel gear  134  in cassette housing  104  can freely rotate with respect to cassette housing  104  about an axis aligned with a coupler axis  131  about which coupler  130  of drive module  68  rotates. In the assembled device module  32 , cassette  66  is positioned on mounting surface of drive module  68  such that cassette bevel gear  134  receives coupler  130  along coupler axis  131  in such a way that it is free to engage and disengage along coupler axis  131  and integrally connected (not free) about coupler axis  131  such that rotation of coupler  130  corresponds equally to rotation of cassette bevel gear  134 . In other words, if coupler  130  rotates clockwise at a given speed, then cassette bevel gear  134  rotates clockwise at the same given speed, and if coupler  130  rotates counterclockwise at a given speed, then cassette bevel gear  134  rotates counterclockwise at the same given speed. 
     Referring to  FIGS. 1, 3, and 4  an EMD drive system includes an on-device adapter  112  removably fixed to a shaft of an EMD  102 . The on-device adapter  112  is received in a cassette  66  removably secured to a drive module  68 . The drive module  68  is operatively coupled to the on-device adapter  112  to move the on-device adapter  112  and EMD  102  together. 
     In one embodiment the on-device adapter  112  is moved in translation. Referring to  FIG. 3  drive module  68  is moved along the X axis to translate the cassette  68 , on-device adapter  112  and EMD  102  together. In one embodiment translation along the x-axis is co-axial to the longitudinal axis of the on-device adapter  112 , the longitudinal axis of the cassette and the longitudinal axis of EMD  102 . Referring to  FIG. 20A  drive module includes a reset function that moves the on-device adapter and EMD in translation. Moving in translation moves the elements noted above along the longitudinal axis of the cassette and on-device adapter in the distal and proximal directions. 
     In one embodiment the on-device adapter is moved in rotation about the longitudinal axis of the on-device adaptor. 
     In one embodiment the on-device adapter  112  includes a collet. Collet can include a variety of collet designs included but not limited to the collets discussed herein. See  FIGS. 6A, 6B, 9A-9I, and 10A-11E . 
     Referring to  FIGS. 6A and 6B  in one embodiment collet  400  includes a first member  402  moving along and/or about a longitudinal axis  406  of the second member  404  to pinch the shaft of EMD  102  within a third member  405 . In one embodiment second member  404  is generally cylindrical. However, second member  404  may be other geometric shapes such as frustoconical with the first portion having a cross section closer to engagement portion  136  that is smaller than a second cross section of a second portion being closer to first member  402 . In one embodiment first member  402  is referred to a nut, second member  404  is referred to as a collet body or sleeve and a third member  405  is referred to as a chuck. Nut  402  is fastened to body  404  to open and close chuck  405  to pinch and unpinch EMD  102 . In one embodiment nut  402  is threadably engaged with body  404 . 
     On-device adapter  112  includes an engagement portion  136  engaged with and driven by a drive member  134  in the cassette  66  to rotate on-device adapter  112 . In one embodiment  136  engagement portion is a gear. However other engagement portions that are driven by drive members are contemplated. 
     In one embodiment on-device  112  adapter includes a surface  408  that is supported by a bearing member in the cassette. 
     In one embodiment the on-device  112  adapter includes a thrust bearing surface  410  preventing translational movement relative to a portion of cassette  66 . In one embodiment the thrust bearing surface  410  includes a first portion  412  preventing translational movement in the distal direction and a second portion  414  preventing translation movement in the proximal direction. In one embodiment first portion  412  and second portion  414  form a groove therebetween defining surface  408  that is supported by a bearing member  133  in cassette  66 . 
     In one embodiment the on-device adapter  112  includes a luer connector  416 . In one embodiment luer connector  416  is covered by ISO 80369-7 standard incorporated herein by reference. In one embodiment luer connector  416  is configured to allow the on-device  112  adapter to be flushed with a cleaning fluid. Luer connector has a passage therethrough connected with a passage in the on-device adapter  112 . In one embodiment the passage is in the luer connector  416  is co-axial and in fluid communication with the passageway in the on-device adapter. In one embodiment the passage in the on-device adapter  112  is the passage that receives the shaft of the EMD  102 . In one embodiment luer connector  41  is a generic connector and in one embodiment it is a connector that falls within ISO 80369-7. In one embodiment luer connector is a luer lock. 
     Referring to  FIGS. 6C and 6D  on-device adapter  112  includes a holder  418  that has a engagement surface or gear  136  formed or attached thereto. Holder  418  has a plurality of slits  420  on a distal portion thereof extend to the distal end of holder  418  forming a plurality of fingers  422 . Holder  418  has a channel that receives a proximal portion of a collet  424 . In one embodiment collet  424  is an off the shelf torque device sold by Merit under the trademark Pin Vise. Collet  424  has a body proximal portion  426  having an outer diameter that is greater than the inner diameter at the distal end of the channel of holder  418 . The proximal end of body  426  is placed within the channel of the holder  418  such that fingers  422  move outward thereby capturing collet  424  within holder  418  such that translation and/or rotation of holder  418  results in translation and/or rotation of collet  424 . A second member  430  rotates about a threaded portion  432  of collet body portion  426  there by pinching a shaft of an EMD within split member portions  428 . Slit member portions  428  move toward one another thereby pinching EMD  102  as the internal cone portion of second member  430  moves toward body portion  426  thereby engaging and moving split member portions  428  toward one another. 
     Referring to  FIGS. 7A and 7B  an on-device adapter  112  is an assembly that includes a quick clamp  450  engaging collet  424  as discussed above. However, it is contemplated that quick clamp  450  engages other collet designs. In one embodiment quick clamp  450  quickly connects and/or releases collet  424 . Referring to  FIGS. 7E and 7F  lever  452  moves from a first unclamped position to a second clamped position to clamp the collet thereto. In one embodiment no additional tool is required to releasably engage the quick clamp onto the collet. Referring to  FIGS. 7A and 7B  quick clamp  450  includes a clamp body  454  defining a channel therethrough that receives a collet  424  such as a torquer described herein above. In one embodiment torquer  424  includes a proximal end  427  that is inserted into a distal opening  429  of the channel  431 . A second portion  430  of the torquer that rotates relative to the body  426  acts to pinch and unpinch an EMD in a channel defined by the body and second portion. Referring to  FIGS. 7E and 7F  lever  452  pivotally attached to a clamp body  454  moves from a first open position to a second closed position in which the clamp body moves from an unclamped to a clamped position. Lever  452  includes a cam portion  457  that interacts with portion  459  on cam body  454 . In the first open position a gap  461  exists between the outer surface of the collet body  454  and the surface of the clamp channel. Gap  461  allows the quick clamp  450  to secure a multitude of different commercially available collets with varying outer body diameters. As lever is pivoted from the open position to the closed position the gap  461  is eliminated there by clamping the collet body to the quick clamp such that translation and/or rotation of the quick clamp results in respective translation and/or rotation of the collet and EMD that is pinched in the collet. Gap  461  is eliminated as cam portion  457  interacts with surface  459  forcing body  454  to eliminate gap  461 . Referring to  FIG. 7B , a screw  455  connected to pin  453  allows for change in gap  461  (in  FIG. 7E ) before the lever  452  is engaged. This allows even more adjustment in the quick clamp for engaging collets with varying outer diameters (lever handles may also be adjusted to fine tune displacements for clamping forces, screw handles large displacements based on changes in size). 
     Referring to  FIG. 7B  a luer connector  456  is operatively coupled to the clamp body  454  with a connector  464  and in one embodiment the luer connector  456  integral with a portion of the clamp body  454 . In one embodiment an engagement portion  458  includes a gear  460  and a surface  462  that is received within the cassette to be supported by a bearing in the cassette. 
     In one embodiment the EMD  102  is removably received in the collet  112  in a radial direction and the collet  112  is removably received and positioned in the cassette. In one embodiment the EMD  102  is removably received in the collet  112  in an axial direction and the collet is removably received in the cassette. In one embodiment the EMD is removably received in the collet  112  in a radial direction and the collet  112  is non-removably positioned within cassette. In one embodiment the EMD  102  is removably received in the collet  112  in an axial direction and the collet  112  is non-removably positioned within the cassette. 
     Referring to  FIG. 4F  the drive module includes an actuator operatively coupled to a drive coupler. That is operatively coupled to a drive member in the cassette. The drive module is operatively coupled to a rail or linear support and a second actuator translates the drive module along the rail or linear support. 
     In one embodiment the EMD is a guidewire. In one embodiment the EMD is a catheter having a hub at a proximal end of the catheter and a flexible shaft extending from the hub toward the distal end of the catheter, wherein the shaft is more flexible than the hub. In one embodiment the catheter includes an intermediary portion between the hub and the shaft that has an intermediate flexibility that is less rigid than the hub and more rigid than the shaft. 
     Referring to  FIGS. 8A and 8B  an on-device adapter  510  holds an EMD  512  which is one embodiment is a catheter. Catheter  512  includes a hub  514  and a shaft  516 . On-device adapter  510  includes a body  518  having a cavity  520  extending therein from a proximal end of body  518  that receives hub  514 . Catheter hub  514  at or adjacent to a proximal end of the catheter  512  and shaft  516  extends from a region proximate hub  514  to a region proximate the distal end of the catheter  512 . In one embodiment hub  514  is received within cavity  520  with a press fit or other engagement to prevent independent translation and/or rotational movement of the catheter  516  from on-device adapter  510 . On-device adapter  510  includes an engagement feature  522  that engages with drive member  134  in cassette  66 . In embodiment engagement feature  522  is a gear. Gear  522  is similar to gear  136  discussed herein. On-device adapter  510  and catheter  512  are translated together with cassette  66  and/or drive module  68 . On-device adapter  510  and catheter  512  are rotated about a longitudinal axis of the on-device adapter  510  and catheter  512  by an actuator operatively rotating gear  134  and thereby rotating gear  522  and on-device adaptor  510  and catheter  512 . 
     Catheter hub  514  includes a hub body  524  and in one embodiment includes a pair of wings  526  extending radially outward from hub body  524 . Referring to  FIGS. 8A and 8B  wings  562  is received within cavity  520  of on-device adapter  510 . In one embodiment catheter  512  includes a connector  528  at a proximal end thereof. In one embodiment, catheter  510  includes a strain relief section  532  intermediate hub  514  and shaft  516  that provides a transition between hub  514  and shaft  516 . In one embodiment, strain relief section  532  has a proximal portion with a proximal diameter and a distal portion with a distal diameter equal or less than the proximal diameter of the shaft  516 . 
     In one embodiment, hub  514  includes a first port to provide access to the inner lumen  534  of the catheter shaft  516  either directly or through hub shaft lumen  534 . In one embodiment hub  514  includes an additional port in fluid communication with a lumen of the catheter that may for example be used for inflation of a balloon. 
     Shaft  516  includes a lumen  534  in fluid communication with a hub lumen  536 . Connector  528  includes a lumen in fluid communication with hub lumen  536  and/or shaft lumen  534 . Another EMD such as a guidewire may enter an opening in connector  528  and extend therethrough into lumen  536  of the hub and lumen  534  of the shaft. In one embodiment strain relief portion surrounds a proximal portion of shaft lumen  534 . Connector  528  also allows for a fluid to be introduced therethrough into the hub lumen  536  and shaft lumen  534  to either flush out the catheter and/or provide fluid to and through the distal end of the catheter shaft  516 . 
     To describe how catheter  512  interacts with another distal catheter, catheter  512  and its features will be referred to as the first catheter and first feature and a distal catheter and its features will be referred to as a second catheter or second feature. First shaft  516  has a given outer diameter to allow first shaft  516  to enter into a second lumen of a second catheter (not shown) and into the vasculature of a patient for diagnostic or therapeutic purposes. The outer diameter of first shaft  516  is less than the inner diameter of a second lumen of the second catheter and thereby can be inserted therein. Note that a guide catheter typically goes into an introducer sheath and not another catheter. Accordingly, a hub of a guide catheter has a geometry such that it cannot enter the introducer sheath and the patient&#39;s vasculature. 
     In contrast, the first hub  514  is not designed to enter into the second lumen of the second catheter or for that matter into introducer sheath lumen. In one embodiment first hub  514  has an outer periphery with a cross section at one location taken perpendicular to the longitudinal axis of the hub and/or catheter that is greater than the inner diameter of the second lumen of the a second catheter hub and/or second lumen of the second catheter. Therefore, the first hub  514  cannot enter into the second lumen of the second catheter. Further the first hub  514  geometry does not permit the proximal end of the catheter to enter into the vasculature. 
     Shaft  516  has a flexibility sufficient to allow the shaft  516  to bend within either a second lumen of a second catheter through which it enters and/or to allow the shaft to follow a non-straight path of the second catheter. In one embodiment the shaft  516  has flexibility sufficient to allow the shaft to bend within and follow a path of non-straight vasculature. 
     In one embodiment, a shaft  516  could include a stainless steel hypotube but still have sufficient flexibility to follow the non-straight path of a second catheter through which the shaft extends and/or a patient&#39;s non-straight vasculature. 
     In one embodiment connector  528  is a luer connector and in one embodiment the luer connector is a female luer connector. In one embodiment the luer connector has a lumen in fluid communication with the lumen of the hub to allow another EMD to pass therethrough or to allow fluid to enter the hub and catheter through the luer connector. 
     In one embodiment hub wings  526  are used by an operator in manual operation to hold on to hub  524 . Wings  526  may be used a location device within cavity  520  of on-device adapter  510 . 
     In one embodiment hub  514  is free of controls used to manipulate features within catheter  512  such as a wire extending to the distal end of the catheter to deflect the tip. In one embodiment catheter  512  does not include any controls used to manipulate features within the catheter such as a wire extending to the distal end of the catheter to deflect the tip. 
     In one embodiment on-device adapter  510  is configured to pinch an EMDs having a range of shaft outer diameters. In one embodiment a Merit Medical torque device is used as part of the on-device adapter to cover one of the following outer shaft diameter ranges: 0.009″ to 0.018″, 0.018″ to 0.038″, 0.010″ to 0.020″, 0.013″ to 0.024″, or 0.025″ to 0.040″. Where the symbol “ designates inches. Note that the torque devices provided by Merit Medical have overlapping ranges. 
     In one embodiment, more than one on-device adapter is used with the robotic drive system depending on the outer diameter of the shaft of the EMD to be pinched. 
     In one embodiment where the robotic system is controlling more than one EMD a first on-device adapter is used for a first EMD having a first outer diameter and a second on-device adapter is sued for a second EMD having a second outer diameter different than the first outer diameter of the first EMD. For example, A first on-device adapter is used to o pinch an angiographic guidewire having an outer diameter of 0.035″ or 0.038″ and the second on-device adapter is sued to pinch a microwire having an outer diameter of approx. 0.014″. An angiographic guidewire, which is used get the guide catheter in place is also called a diagnostic guidewire. And a microwire could be referred to as a micro-guidewire or simply a guidewire. For clarity the term approx. used herein is an abbreviation for the word approximately. 
     In one embodiment, the on-device adapter does not need to be designed to be disassembled. In one embodiment, the on-device adapter may be designed to accept a single torquer. Note that the terms torquer and torque device are used interchangeably herein and are a subset of a collet as used herein. In one embodiment, the on-device adapter provides sufficient clamping force on the torque device to withstand axial force when the on-device adapter is being advanced and retracted and withstand torsional force when the on-device is being rotated to rotate an EMD for a given procedure. The pinch or clamping force applied to the torquer by the on-device adapter is sufficient to resist slippage (axial or rotational) of the EMD being advanced and/or rotated along with the on-device adapter. In one embodiment, the on-device adapter penetrates an outer surface of the torque device body and/or deforms a surface of the torque device. 
     Referring to  FIGS. 12A-12F . 2  a robotic system  910  includes a collet  964  having a first portion  965  having a first collet coupler  958  connected thereto and a second portion  966  having a second collet coupler  960  connected thereto. Referring to  FIG. 12F . 1  EMD  912  is removably located within a lumen or pathway  996  defined by collet  964 . A robotic drive including a drive module or base  914  having a first motor  936  and a second motor  938  operatively continuously coupled to both first collet coupler  958  and the second collet coupler  960  to operatively pinch and unpinch EMD  914  in the lumen  996  and to rotate EMD  912 . As discussed herein first motor  936  and second motor  938  differentially rotate first collet coupler  958  and second collet coupler  960 . Stated another way first motor  936  and second motor  938  rotate at different rates and in different directions independent of one another including where one motor rotates and the second motor does not rotate. In one embodiment both motors rotate at the same rate. In one embodiment the first motor and the second motor are continuously engaged with the first collet coupler  958  and the second collet coupler  960  respectively. In one embodiment first portion  965  and first collet coupler  958  are formed as a single component and in one embodiment they are separate components. In one embodiment second portion  966  and second collet coupler  960  are formed as a single component and in one embodiment they are separate components. 
     EMD robotic system  910  includes a collet employing a double-gear arrangement that releasably engages EMD  912  and rotates and translates EMD  912 . In one embodiment the double-gear arrangement includes double-bevel gears. The double-gear collet-drive system  910  has a proximal end  911  and a distal end  913 . As EMD  912  is moved from the proximal end  911  toward the distal end  913  the EMD  912  is being advanced into the patient and when the EMD  912  is moved from the distal end  913  toward the proximal end the EMD  912  is being retracted or withdrawn from the patient. In order to clarify directions, a rectangular coordinate system is introduced with X, Y, and Z axes. The positive Z axis is oriented in a longitudinal (axial) distal direction, that is, in the direction from the proximal end to the distal end. The X and Y axes are in a transverse plane to the Z axis, with the positive Y axis oriented up, that is, in the direction opposite of gravity, and the X axis in a direction toward the front (typically pointing toward the operator/physician who is bedside). The right-hand rule is adopted to determine the sense of rotational direction, that is, the orientation convention is determined by pointing the thumb of the right hand along the positive X, Y, and Z axis direction and then the curl of the fingers of the right hand is associated with the clockwise direction. The direction opposite the curl of the fingers of the right hand is associated with the counterclockwise direction. The terms clockwise and counterclockwise as used herein are relative terms indicating a first direction of rotation and a second direction of rotation that is opposite to the first direction of rotation. Accordingly, any use of the term clockwise and counterclockwise are to be understood to mean a first direction of rotation and a second opposing direction of rotation. The terms clockwise and counterclockwise have been used to assist in following the different rotational directions of the devices provided herein, however it is possible that the devices could be constructed with the clockwise and counterclockwise directions are reversed. 
     The collet-drive system  910  includes a drive module  914  that translates along an axial direction of EMD  912  and is actuated by a drive module translational drive  916 . Drive module  914  includes a drive module housing  918 , a mount bracket  920 , a cassette  922 , and a cassette cover  924 . The cassette  922  includes a double-gear collet-drive housing  926  and EMD guides  928 . The top of the double-gear collet-drive housing  926  includes multiple openings  927  and multiple ribs  929 . The EMD guides  928  include multiple pairs of guides that act as v-shaped notches and serve as an open channel for guiding EMD  912  through the drive system. Note that the open channel is open for loading but covered when the cassette cover is in the closed position. The guides act as anti-buckling features. In one embodiment EMD guides  928  include multiple pairs of v-shaped notches or u-shaped channels that act as guides. The tops of the v-shaped or u-shaped channels may be chamfered to assist in loading the EMD  912 . In one embodiment one pair of EMD guides  928  is used on the proximal side of the double-gear collet-drive housing  926  and one pair of EMD guides  928  is used on the distal side of the double-gear collet-drive housing  926 . In one embodiment multiple pairs of EMD guides  928  are used on the proximal side of the double-gear collet-drive housing  926  and multiple pairs of EMD guides  928  are used on the distal side of the double-gear collet-drive housing  926 . 
     In one embodiment robotic system  910  includes a third motor  932  (not shown) operatively coupled to collet  964  to translate collet  964  and EMD  912  along a longitudinal axis of collet  964 . In one embodiment first motor  936  and second motor  938  are fixed relative to collet  964  during translation of the collet and EMD. The drive module translational drive  916  includes a lead screw  930  driven by a screw drive motor  932  (not shown) inside of a screw drive housing  934 . The screw drive  930  is used to translate drive module  914  relative to fixed housing  934 . In one embodiment screw drive motor  932  is a stepper motor. In one embodiment screw drive motor  932  is a servo motor. In one embodiment screw drive motor  932  is a rotational actuator powered by electrical, pneumatic, hydraulic, or other means. 
     In one embodiment drive module housing  918  and its contents are reusable. In one embodiment cassette  922  is consumable and meant to be disposed of after use with a single patient. In one embodiment cassette  922  may be made of a material that is sterilizable and reused. 
     Referring to  FIGS. 12A and 12B  the drive module housing  918  contains a first motor  936  that is operatively connected to and drives a first coupler  940  and a second motor  938  that is operatively connected to and drives a second coupler  942 . In one embodiment first motor  936  and second motor  938  are stepper motors. In one embodiment first motor  936  and second motor  938  are servo motors. In one embodiment first motor  936  and second motor  938  are rotational actuators powered by electrical, pneumatic, hydraulic, or other means. 
     First coupler  940  passes through drive module housing  918  and is integrally connected to a first coupler bevel gear  946 . Second coupler  942  passes through mount bracket  920  and is integrally connected to a second bevel gear  948 . First motor  936 , first coupler  940 , and first coupler bevel gear  946  are located distally in the drive module housing  918 . Second motor  938 , second coupler  942 , and second coupler bevel gear  948  are located proximally in the drive module housing  918 . In one embodiment first coupler  940  and second coupler  942  pass through holes in mount bracket  920 . In one embodiment first coupler  940  and second coupler  942  pass through rotational bearings that are mounted in mount bracket  920 . 
     The collet-drive housing  926  contains a double-gear collet-drive assembly  944 , described herein. 
     Referring to  FIGS. 12B and 12C  first driven bevel gear  950  meshes with and is driven by first coupler bevel gear  946 . First driven bevel gear  950  is integrally connected to a first shaft distal portion  951 , which is integrally connected to a first wheel  954 , which is integrally connected a first shaft proximal portion  953 , all of which form a first compound (or cluster) assembly  958 . Second driven bevel gear  952  meshes with and is driven by second coupler bevel gear  948 . Second driven bevel gear  952  is integrally connected to a second shaft proximal portion  955 , which is integrally connected to a second wheel  954 , which is integrally connected a second shaft distal portion  957 , all of which form a second compound (or cluster) assembly  960 . 
     In one embodiment a top face  947  of first coupler bevel gear  946  includes an open central hole along its central axis to receive and drive first coupler  940 . Stated another way gear  946  has a hole along its longitudinal axis. In one embodiment top face  947  of first coupler bevel gear  946  is not open but sealed to prevent migration of fluids from the cassette into the base. In one embodiment a top face  949  of second coupler bevel gear  948  includes an open central hole along its central axis to receive and drive second coupler  942 . In one embodiment top face  949  of second coupler bevel gear  948  is not open but sealed to prevent migration of fluids from the cassette into the base. 
     In one embodiment cassette  922  is removably secured to the base  914 . Collet  964  is positioned within cassette  922 . The first collet coupler  958  and the second collet coupler  960  are respectively coupled to the first motor  936  and the second motor  938  via a first drive coupler  940  and a second drive coupler  942  positioned within the base  914 . In one embodiment first drive coupler  940  includes a shaft operatively connected to motor  936  and extending from the base in a sealed manner and is operatively connected to gear  946  that is operatively engaged with first collet coupler  958 . Similarly, second drive coupler  942  includes a shaft operatively connected to motor  938  and extending from the base in a sealed manner and is operatively connected to gear  948  that is operatively engaged with second collet coupler  960 . 
     The first compound assembly  958  contains a radial longitudinal slit  962  extending from an outer surface of the assembly and terminating at its radial center. The second compound assembly  960  contains a radial longitudinal slit  963  extending from an outer surface of the assembly and terminating at its radial center. Slits  962  and  963  allow for side or radial loading of EMD  912 . In one embodiment slits  962  and  963  create radial openings with opposing nonparallel walls. In one embodiment slits  962  and  963  create approximately radial openings with opposing parallel walls. In one embodiment the outer surfaces of assemblies  958  and  960  contain v-shaped notches directed toward their center longitudinal axes that lead into the slits  962  and  963 , respectively, to help guide EMD  912  for side or radial loading. It is noted that slit  962  extends through first driven bevel gear  950  and slit  963  extends through second driven bevel gear  952 . First coupler bevel gear  946  meshes with and drives first driven bevel gear  950  with slit  962  without compromising performance. Second coupler bevel gear  948  meshes with and drives second driven bevel gear  952  with slit  963  without compromising performance. 
     Referring to  FIG. 12A  an outer portion of first wheel  954  and an outer portion of second wheel  956  extend through openings  927  in housing  926 , making the wheels  954  and  956  accessible for manual manipulation by an operator. For example, in the event of a power loss the operator can manually rotate wheels  954  and  956  for removal of EMD  912 . In one embodiment the operator can remove the collet assembly including wheels  954  and  956  from the cassette by also removing double-bevel collet-drive housing  926  from cassette allowing the operator to align the slots in the collet assembly to remove the EMD out of the cassette. In one embodiment first wheel  954  and second wheel  956  are circular disks with notches on their outer circumferential peripheries. In one embodiment first wheel  954  and second wheel  956  are circular disks with grooves on their outer circumferential peripheries. In one embodiment first wheel  954  and second wheel  956  are circular disks with knurls on their outer circumferential peripheries. In one embodiment first wheel  954  and second wheel  956  are circular disks with features that aid in manual manipulation on their outer circumferential peripheries. In one embodiment first wheel  954  and second wheel  956  are circular disks with no features, such as smooth walls, on their outer circumferential peripheries. 
     Referring to  FIGS. 12A, 12B, and 12C  the first compound assembly  958  and the second compound assembly  960  each rotate about a longitudinal axis aligned with EMD  912  and each assembly is maintained in position longitudinally by circular cutouts in ribs  929  that serve as bearings. In one embodiment open circular cutouts in ribs  929  snap over and onto both sides of first wheel  954  and second wheel  956 . In other words, the first compound assembly  958  and the second compound assembly  960  can be snapped in to open cutouts in ribs  929  that partially surround the first shaft distal portion  951  and the first shaft proximal portion  953  of first compound assembly  958  and the second shaft proximal portion  955  and the second shaft distal portion  957  of second compound assembly  960 . The open cutouts in ribs  929  act like thrust bearings preventing axial (longitudinal) motion and freely allowing rotational motion. The open cutouts in ribs  929  do not completely enclose the shafts  951 ,  953 ,  955 , and  957 . In one embodiment the open cutouts in ribs  929  offer an enclosure of 210 degrees about each of the shafts  951 ,  953 ,  955 , and  957 . In one embodiment the open cutouts offer an enclosure of greater than 180 degree and less than 360 degree of each of the shafts  951 ,  953 ,  955 , and  957 . In one embodiment the ribs with open cutouts are made of a material, such as plastic, with inherent compliance. 
     Referring to  FIGS. 12A and 12D  the double-gear collet-drive assembly  944  includes the first compound assembly  958 , a collet  964  including an internal collet portion  965 , an outer collet portion  966  having a screw spline, and the second compound assembly  960 . Due to the snap fit feature of the open cutouts in ribs  929  the double-gear collet-drive assembly  944  (which does not include first coupler bevel gear  946  or second coupler bevel gear  948 ) can be manually removed from the housing  926  and reseated. 
     Referring to  FIGS. 12D and 12E  inner collet portion  965  includes a collet first section  968  integrally connected to a collet tapered second section  970  that is split into opposing cantilevered tapered jaws  972  with approximately semi-circular cross-sections. In one embodiment collet first section  968  has a prismatic shape with a generally constant radius. In one embodiment collet first section  968  has a prismatic shape with a square cross-section. In one embodiment collet  968  has a non-prismatic shape with a non-constant cross-section. Collet second section  970  extends from collet first section  968  in a frusto-conical manner such that the diameter of the second section continuously decreases from a region immediately adjacent the first section to a proximal free end  974  of the second section  970 , where the proximal end  974  is furthest from the region of the second section immediately adjacent the first section  968 . In one embodiment inner collet portion  965  and first compound assembly  958  are separate components. For example, collet tapered second section  970  could be a pressed metal insert into collet first section  968 . In one embodiment inner collet portion  965  and first compound assembly  958  are combined into one component. Collet  964  may be any collet device known in the art including but not limited to the collet embodiments described herein. 
     Screw spline  966  includes a screw spline first section  976  integrally connected to a screw spline second section  978 . The screw spline first section  976  contains external longitudinal spline threads  980  that mesh with the internal longitudinal spline threads  982  of the second compound assembly  960  and allow for relative translational motion in the longitudinal direction  988 . The screw spline second section  978  contains external spiral circumferential screw threads  984  that mesh with internal screw threads  986  of the first compound assembly  958  and allow for relative rotational motion in the clockwise or counterclockwise directions  990 . The design of the screw spline  966  with both longitudinal spline threads  980  and spiral circumferential screw threads  984  allows the screw spline  966  to be rotated and translated relative to the inner collet portion  965  while maintaining fixed longitudinal distances between first driven coupler bevel gear  950  and second driven coupler bevel gear  952  such that they can mesh, respectively with first coupler bevel gear  946  and second coupler bevel gear  948 . 
     In one embodiment EMD  912  does not rotate while EMD  912  is being pinched and unpinched. Collet first section  968  is the section that releasably fixes EMD  912  thereto. By maintaining collet first section  968  stationary while rotating second section  966  portion EMD  912  does not rotate. Stated another way, unpinching of EMD from collet  964  without imparting any rotation to EMD  912  about the longitudinal axis of collet  964  is accomplished by maintaining internal collet portion  965  of the collet that is in direct fixed contact with EMD  192  stationary relative to the patient as outer collet portion  966  is rotated relative to inner collet portion  965  releasing EMD  192  from a fixed relationship to inner collet  965 . In one embodiment it may desirable to continue to rotate EMD  912  during the beginning of the unpinch process. In this embodiment first collet section  968  rotates at a different rate than outer collet portion  966 . 
     Referring to  FIGS. 12D and 12E  inner collet portion  965  contains a radial longitudinal slit  992  in collet first section  968  to allow for side or radial loading of EMD  912  into lumen  996 . Longitudinal slit  992  extends radially from an outer surface of first section  968  and terminates at a radial center of inner collet portion  965 . Longitudinal slit  992  extends longitudinally to second tapered section  970  through the seam of the jaws  972 . Screw spline  966  contains a radial longitudinal slit  994  to allow for side or radial loading of EMD  912 . Longitudinal slit  994  extends radially from an outer surface of screw spline  966  and terminates at its center. 
     Referring to  FIG. 12F . 1  in the unpinched configuration of double-gear collet-drive assembly  944  jaws  972  of collet tapered second section  972  are open and do not lock down (do not pinch) onto EMD  912 . In the fully unpinched configuration screw spline  966  is in its most proximal position. In one embodiment screw spline  966  is limited to its most proximal position by a hard stop at the proximal end of its longitudinal spline. In one embodiment screw spline  966  is limited to its most proximal position by a feature, such as a flange or lip, to stop further travel in the longitudinal spline. Referring to  FIG. 12F . 2  in the pinched configuration of double-gear collet-drive assembly  944  jaws  972  of collet tapered second section  972  are closed together and lock (pinch) down onto EMD  912 . In the fully pinched configuration screw spline  966  is in its most distal position. In one embodiment screw spline  966  is limited to its most distal position by a hard stop due to running out of thread, that is, it cannot be screwed in further as it is constrained by geometry. In one embodiment screw spline  966  is limited to its most distal position by a feature, such as a flange or lip, to stop further travel. 
     Referring to  FIGS. 12F . 1  and  12 F. 2  movement of inner collet portion  965  in the direction of screw spline  966  causes the jaws  972  of collet tapered second section  972  to move toward one another to pinch EMD  912 . Movement of inner collet portion  965  away from the direction of screw spline  966  causes the jaws  972  of collet tapered second section  972  to move away from one another to unpinch EMD  912 . 
     In operation double-gear collet-drive assembly  944  uses two rotational degrees of freedom from motors  936  and  938  to achieve four operations, namely, to pinch EMD  912 , to unpinch EMD  912 , to rotate clockwise double-gear collet-drive assembly  944 , and to rotate counterclockwise double-gear collet-drive assembly  944 . The four operations occur by movement of inner collet portion  965  relative to screw spline  966  based on rotation direction of first coupler  940  and rotation direction of second coupler  942 . 
     In a first mode of operation, in which the result is the double-gear collet-drive assembly  944  rotates in a clockwise direction, first coupler  940  rotates in a counterclockwise direction and second coupler  942  rotates in a clockwise direction. In a second mode of operation, in which the result is the double-gear collet-drive assembly  944  rotates in a counterclockwise direction, first coupler  940  rotates in a clockwise direction and second coupler  942  rotates in a counterclockwise direction. In a third mode of operation, in which the result is the EMD  912  is unpinched, first coupler  940  does not rotate and second coupler  942  rotates in a counterclockwise direction. In a fourth mode of operation, in which the result is the EMD  912  is pinched, first coupler  940  does not rotate and second coupler  942  rotates in a clockwise direction. In the third mode and fourth mode of operations, the collet becomes unpinched or pinched, respectively. In one embodiment in the third mode and the fourth mode motion continues until a hard stop is reached. In one embodiment in unpinching a hard stop is reached when arriving at the end of the spline threads on the screw spline first section  976 . In one embodiment in pinching a hard stop is reached when arriving at the end of the threads on the screw spline second section  978  where it meets the screw spline first section  976 . For faster initiation of rotation of EMD during pinch during the fourth mode, first coupler  940  is rotated clockwise. 
     First motor  936  and second motor  938  can be controlled to constrain the amount of torque that each motor can apply. In one embodiment in which first motor  936  and second motor  938  are servomotors, each motor can be controlled with current limits to constrain the torque that each motor can apply. Current limits can be set at different values for the third mode and fourth mode of operations. For example, the currents can be limited to lower values for pinching than for unpinching since in unpinching static friction must be overcome. 
     In one embodiment double-gear collet-drive system  910  incorporates a system to prevent buckling of EMD  912  at the proximal end  911  of the collet-drive system. In one embodiment double-gear collet-drive system  910  incorporates a system to prevent buckling of EMD  912  at the distal end  913  of the collet-drive system. In one embodiment the system to prevent buckling is a tube with an inner diameter slightly larger than the outer diameter of EMD  912 . In one embodiment the system to prevent buckling is a set of telescoping tubes with the inner diameter of the smallest tube slightly larger than the outer diameter of EMD  912 . In one embodiment the system to prevent buckling is a side-loadable track. 
     Referring to  FIG. 13A  a double-gear sliding collet-drive system  1000  releasably engages an elongated medical device (EMD)  1002  and rotates and translates EMD  1002 . The double-gear sliding collet-drive system  1000  includes a proximal end  1004  and a distal end  1006 . As EMD  1002  is moved from the proximal end  1004  toward the distal end  1006  EMD  1002  is being advanced into the patient and as EMD  1002  is moved from the distal end  1006  toward the proximal end  1004  EMD  1002  is being retracted or withdrawn from the patient. 
     Sliding collet-drive system  1000  includes a carrier  1008  that translates along an axial direction of EMD  1002  actuated by a carrier translational drive  1010  that is mounted to a fixed base  1012 . Carrier  1008  includes a carrier housing  1014 , a carrier arm  1016 , and a rack  1018 , all three of which are integrally connected. Carrier translational drive  1010  includes a pinion gear  1020  integrally connected to a motor shaft (not shown) of translational drive motor  1022 . Translational drive motor  1022  rotates pinion gear  1020  that meshes with rack  1018  to translate carrier  1008 . Linear guides or linear bearings (not shown) integrally connected to base  1012  constrain carrier  1008  to translational motion only in the proximal and distal directions along EMD  1002  axis. 
     Carrier housing  1014  includes a flat base plate with perpendicular side extensions on its proximal and distal ends. In one embodiment carrier housing  1014  is one integrated piece with base plate, proximal extension, and distal extension made of the same material. In one embodiment carrier housing  1014  includes a base plate, a proximal extension, and a distal extension as three separate pieces made of the same material that are integrally connected. In one embodiment carrier housing  1014  includes a base plate, a proximal extension, and a distal extension as three separate pieces made of different materials that are integrally connected. The proximal and distal extensions of carrier housing  1014  include holes that support a collet-and-rotational-drive system  1024  (described below). In one embodiment rotational bearings are mounted in the holes in the proximal and distal extensions of carrier housing  1014 . 
     A first motor  1026  and a second motor  1028  are mounted to fixed base  1012 . In one embodiment first motor  1026  and second motor  1028  are fixed relative to base  1012  during translation of collet  1056  and EMD  1002 . As described herein carrier  1008  is translated with collet  1056  independently of base  1012  and first motor  1026  and second motor  1028 . Stated another way, at least during one mode of operation when collet  1056  is translated along its longitudinal axis the first motor  1026  and second motor  1028  are not translated with collet  1056 . First motor  1026  drives a first coupler  1030 . Second motor  1028  drives a second coupler  1032 . First motor  1026  and first coupler  1030  are located below or within base  1012 . Second motor  1028  and second coupler  1032  are located proximally below fixed base  1012 . In one embodiment first coupler  1030  and second coupler  1032  pass through holes in the fixed base  1012 . In one embodiment first coupler  1030  and second coupler  1032  pass through rotational bearings and seals that are mounted in the fixed base  1012 . 
     In one embodiment translational drive motor  1022 , first motor  1026 , and second motor  1028  are stepper motors however other motor types known in the art are also contemplated. In one embodiment translational drive motor  1022 , first motor  1026 , and second motor  1028  are servo motors. In one embodiment translational drive motor  1022 , first motor  1026 , and second motor  1028  are rotational actuators powered by electrical, pneumatic, hydraulic, or other means. 
     Referring to  FIGS. 13B . 1  and  13 B. 2  the collet-and-rotational-drive system  1024  (described below) translates relative to fixed base  1012 . Referring to  FIG. 13B . 1  translational drive motor  1022  rotates pinion  1020  in one direction (clockwise) such that rack  1018  and hence the collet-and-rotational-drive system  1024  are translated in the proximal direction. Referring to  FIG. 13B  translational drive motor  1022  rotates pinion  1020  in the opposite direction (counterclockwise) such that rack  1018  and hence the collet-and-rotational-drive system  1024  are translated in the distal direction. In one embodiment collet-and-rotational-drive system  1024  translates relative to fixed base  1012  by the rack and pinion mechanism described herein. In one embodiment collet-and-rotational-drive system  1024  translates relative to fixed base  1012  by a different mechanism, such as a reciprocating mechanism in the form of a slider-crank or Scotch-yoke mechanism. An advantage of a reciprocating mechanism is that translational drive motor  1022  would not need to change direction. 
     Translation of collet-and-rotational-drive system  1024  is accomplished without needing to translate first motor  1026  (and first coupler  1030  and first driver bevel gear  1034 ) and second motor  1028  (and second coupler  1030  and second driver bevel gear  1042 ), both of which are mounted to fixed base  1012 . Hence, inertial issues of translational acceleration and translational deceleration of first motor  1026  and second motor  1028  are avoided. 
     Referring to  FIG. 13C  first coupler  1030  is integrally connected to a first driver bevel gear  1034  that meshes with a first driven bevel gear  1036 . First driven bevel gear  1036  is integrally connected to a first shaft  1037 , which is integrally connected to a first spur gear  1038 , all of which form a first compound (or cluster) gear assembly  1040 . Second coupler  1032  is integrally connected to a second driver bevel gear  1042  that meshes with a second driven bevel gear  1044 . Second driven bevel gear  1044  is integrally connected to a second shaft  1045 , which is integrally connected to a second spur gear  1046 , all of which form a second compound (or cluster) gear assembly  1048 . First spur gear  1038  meshes with a first collet spur gear  1050  that can translate relative to first spur gear  1038 . Second spur gear  1046  meshes with a second collet spur gear  1052  that can translate relative to second spur gear  1046 . At the distal end of first collet spur gear  1050  is a short first shaft  1051  that is coaxially aligned and integrally connected to first collet spur gear  1050 . At the proximal end of second collet spur gear  1052  is a short second shaft  1053  that is coaxially aligned and integrally connected to second collet spur gear  1052 . In one embodiment first shaft  1051  is supported by a hole in the distal extension of carrier housing  1014 . In one embodiment first shaft  1051  is supported by a rotational bearing mounted in a hole in the distal extension of carrier housing  1014 . In one embodiment second shaft  1053  is supported by a hole in the proximal extension of carrier housing  1014 . In one embodiment second shaft  1053  is supported by a rotational bearing mounted in a hole in the proximal extension of carrier housing  1014 . 
     First collet spur gear  1050  and second collet spur gear  1052  are wide gears, that is, they are elongated gears wider than the widths of first spur gear  1038  and second spur gear  1046 . In one embodiment the widths of first collet spur gear  1050  and second collet spur gear  1052  are ten times the widths of first spur gear  1038  and second spur gear  1046 , respectively. In one embodiment the widths of first collet spur gear  1050  and second collet spur gear  1052  are less than ten times the widths of first spur gear  1038  and second spur gear  1046 , respectively. In one embodiment the widths of first collet spur gear  1050  and second collet spur gear  1052  are greater than ten times the widths of first spur gear  1038  and second spur gear  1046 , respectively. 
     First compound gear assembly  1040  and second compound gear assembly  1048  are supported relative to base  1012  in such a way that they are coaxially aligned and can rotate about a longitudinal axis. In one embodiment first shaft  1037  connecting first driven bevel gear  1036  and first spur gear  1038  passes through and is supported by a hole in an extension from base  1012 . In one embodiment first shaft  1037  connecting first driven bevel gear  1036  and first spur gear  1038  passes through and is supported by a rotational bearing in an extension from base  1012 . In one embodiment second shaft  1045  connecting second driven bevel gear  1044  and second spur gear  1046  passes through and is supported by a hole in an extension from base  1012 . In one embodiment second shaft  1045  connecting second driven bevel gear  1044  and second spur gear  1046  passes through and is supported by a rotational bearing in an extension from base  1012 . 
     Referring to  FIGS. 13A and 13C  the collet-and-rotational-drive  1024  includes first collet spur gear  1050  with first shaft  1051 , a collet mechanism  1054  (described below), and second collet spur gear  1052  with second shaft  1053 , all coaxially aligned along a longitudinal axis. In one embodiment collet-and-rotational-drive  1024  can be manually removed from carrier housing  1014  and reseated into carrier housing  1014  due to snap fit features built into the proximal side and distal side of carrier housing  1014 . 
     In one embodiment first collet spur gear  1050  is integrally connected to a first wheel (not shown) that has a larger diameter than that of spur gear  1050  and second collet spur gear  1052  is integrally connected to a second wheel (not shown) that has a larger diameter than that of spur gear  1052 . The first wheel and second wheel would be accessible for manual manipulation by an operator. For example, in the event of a power loss the operator could manually rotate the first wheel and second wheel for removal of EMD  1002 . In one embodiment the first wheel and second wheel are circular disks with notches on their outer circumferential peripheries. In one embodiment the first wheel and second wheel are circular disks with grooves on their outer circumferential peripheries. In one embodiment the first wheel and second wheel are circular disks with teeth on their outer circumferential peripheries. In one embodiment the first wheel and second wheel are circular disks with features that aid in manual manipulation on their outer circumferential peripheries. In one embodiment the first wheel and second wheel are circular disks with no features, such as smooth walls, on their outer circumferential peripheries. In one embodiment first collet spur gear  1050  and the first wheel are a single integrated component made of the same material and second collet spur gear  1052  and the second wheel are a single integrated component made of the same material. In one embodiment first collet spur gear  1050  and the first wheel are separate components integrally combined and second collet spur gear  1052  and the second wheel are separate components integrally combined. 
     In one embodiment carrier arm  1016  can be manually removed from the proximal side of carrier housing  1014  and reconnected to the proximal side of carrier housing  1014  due to snap fit features built into the proximal side of carrier housing  1014 . In one embodiment carrier arm  1016  can be manually removed from rack  1018  and reconnected to rack  1018  due to snap fit features built into the distal side of rack  1018 . 
     In one embodiment collet-and-rotational-drive  1024  is consumable. In one embodiment collet-and-rotational-drive  1024  and carrier  1008  are consumable. In one embodiment collet-and-rotational-drive  1024  and carrier housing  1014  are consumable. In one embodiment collet-and-rotational-drive  1024 , carrier housing  1014 , and carrier arm  1016  are consumable. 
     Referring to  FIG. 13D . 1  and  FIG. 13D . 2  first collet spur gear  1050  and second collet spur gear  1052  are connected by internal components of a collet mechanism  1054 . Collet mechanism  1054  includes a collet inner member  1056  and a collet outer member  1058 . Collet inner member  1056  and outer member  1058  may be any collet device known in the art including but not limited to the collet embodiments described herein 
     Collet inner member  1056  is comprised of a first section  1060  and a second section  1062 . First section  1060  of collet inner member  1056  has a cylindrical collar or sleeve shape with the center of its longitudinal axis colinear with the axis of EMD  1002  and with its outer circumferential surface integrally connected to the internal wall  1064  of first collet spur gear  1050 . Second section  1062  of collet inner member  1056  has a tapered shape toward the center longitudinal axis with an internal lumen. In one embodiment second section  1062  of collet inner member  1056  includes two separated tapered jaws. In one embodiment second section  1062  of collet inner member  1056  includes more than two separated tapered jaws. In one embodiment first section  1060  and second section  1062  of collet inner member  1056  and first collet spur gear  1050  are one integrated piece. In one embodiment first section  1060  and second section  1062  of collet inner member  1056  and first collet spur gear  1050  are separate pieces that are integrally connected. 
     Collet outer member  1058  is comprised of a first section  1066  and a second section  1068 . First section  1066  of collet outer member  1058  has a cylindrical collar or sleeve shape with the center of its longitudinal axis colinear with the axis of EMD  1002  and with its outer circumferential surface integrally connected to the internal wall  1070  of second collet spur gear  1052 . Second section  1068  of collet outer member  1058  has a cylindrical collar or sleeve shape with external screw threads  1074  on its outside circumference and with the center of its longitudinal axis colinear with the axis of EMD  1002 . In one embodiment first section  1066  and second section  1068  of collet outer member  1058  and second collet spur gear  1052  are one integrated piece. In one embodiment first section  1066  and second section  1068  of collet outer member  1058  and second collet spur gear  1052  are separate pieces that are integrally connected. 
     The external screw threads  1074  of second section  1068  of collet outer member  1058  mesh with internal screw threads  1072  of second section  1062  of collet inner member  1056 . Due to meshing of internal screw threads  1072  with external screw threads  1074  rotation of collet inner member  1056  relative to collet outer member  1058  about a longitudinal axis corresponds to translation of collet inner member  1056  relative to collet outer member  1058  along a longitudinal axis. Since first collet spur gear  1050  is integrally connected to collet inner member  1056  and second collet spur gear  1052  is integrally connected to collet outer member  1058 , rotation of first collet spur gear  1050  relative to second collet spur gear  1052  about a longitudinal axis corresponds to translation of first collet spur gear  1050  relative to second collet spur gear  1052  along a longitudinal axis. Rotation of first collet spur gear  1050  is accomplished by its mesh with first spur gear  1038 . Rotation of second collet spur gear  1052  is accomplished by its mesh with second spur gear  1046 . 
     To ensure continuous meshing between first collet spur gear  1050  and first spur gear  1038 , first collet spur gear  1050  is made wider than first spur gear  1038 . This is needed to accommodate the translation of first collet spur gear  1050  as it is rotated by first spur gear  1038  and to accommodate the translation of first collet spur gear  1050  as it is translated by carrier  1008 . To ensure continuous meshing between second collet spur gear  1052  and second spur gear  1046 , second collet spur gear  1052  is made wider than second spur gear  1046 . This is needed to accommodate the translation of second collet spur gear  1052  as it is rotated by second spur gear  1046  and to accommodate the translation of second collet spur gear  1052  as it is translated by carrier  1008 . In one embodiment first collet spur gear  1050  and second collet spur gear  1052  remain engaged with the first motor  1026  and second motor  1028  during translation of collet  1054 . Stated another way first collet spur gear  1050  includes teeth having a face width of sufficient length to permit engagement of the teeth of gear  1050  with gear  1038  as gear  1050  is translated along with collet  1054  with respect to motor  1026 . Similarly, second collet spur gear  1052  includes teeth having a face width of sufficient length to permit engagement of the teeth of gear  1052  with gear  1046  as gear  1052  is translated along with collet  1054  with respect to motor  1028 . 
     Referring to  FIG. 13D . 1  in the unpinched configuration of the collet-and-rotational-drive system  1024  the jaws of second section  1062  of collet inner member  1056  are open and do not lock down (do not pinch) onto EMD  1002 . In the fully unpinched configuration collet outer member  1058  is in its most proximal position relative to collet inner member  1056 . In one embodiment collet outer member  1058  is limited to its most proximal position by a hard stop at the proximal end of its travel. In one embodiment collet outer member  1058  is limited to its most proximal position by a feature, such as a flange or lip, to stop further travel in the longitudinal direction. Referring to  FIG. 13D . 2  in the pinched configuration of the collet-and-rotational-drive system  1024  the jaws of second section  1062  of collet inner member  1056  are closed together and lock (pinch) down onto EMD  1002 . In the fully pinched configuration collet outer member  1058  is in its most distal position relative to collet inner member  1056 . In one embodiment the collet outer member  1058  is limited to its most distal position by a hard stop due to running out of thread, that is, it cannot be screwed in further as it is constrained by geometry. In one embodiment the collet outer member  1058  is limited to its most distal position by a feature, such as a flange or lip, to stop further longitudinal travel. 
     The principle of operation of the collet-and-rotational-drive system  1024  is similar to that of the collet of the double-gear collet-drive assembly  944  of  FIG. 12C  and  FIG. 12  D. As first collet spur gear  1050  and second collet spur gear  1052  are rotated such that they are threaded toward one another, the inner surface of second section  1068  of collet outer member  1058  presses against second section  1062  of collet inner member  1056  and pinches down on EMD  1002 . As first collet spur gear  1050  and second collet spur gear  1052  are rotated such that they are unthreaded away from one another, the inner surface of second section  1068  of collet outer member  1058  relaxes and stops pressing against second section  1062  of collet inner member  1056  and unpinches EMD  1002 . 
     In operation the double-gear collet-and-rotational drive system  1024  uses two rotational degrees of freedom from motors  1026  and  1028  to achieve four operations, namely, to pinch EMD  1002 , to unpinch EMD  1002 , to rotate clockwise double-gear collet-and-rotational drive system  1024 , and to rotate counterclockwise double-gear collet-and-rotational drive system  1024 . The four operations occur by movement of collet inner member  1056  relative to collet outer member  1058  based on rotation direction of first coupler  1030  and rotation direction of second coupler  1032 . 
     In a first mode of operation, in which the result is the double-gear collet-and-rotational drive system  1024  rotates in a clockwise direction, first coupler  1030  rotates in a clockwise direction and second coupler  1032  rotates in a counterclockwise direction. In a second mode of operation, in which the result is the double-gear collet-and-rotational drive system  1024  rotates in a counterclockwise direction, first coupler  1030  rotates in a counterclockwise direction and second coupler  1032  rotates in a clockwise direction. In a third mode of operation, in which the result is the EMD  1002  is unpinched, first coupler  1030  rotates in a clockwise direction and second coupler  1032  rotates in a clockwise direction. In a fourth mode of operation, in which the result is the EMD  1002  is pinched, first coupler  1030  rotates in a counterclockwise direction and second coupler  1032  rotates in a counterclockwise direction. In the third mode and fourth mode of operations, collet inner member  1056  unpinches or pinches, respectively, EMD  1002  until a hard stop is reached. 
     In one embodiment pinching and unpinching of collet mechanism  1054  is synchronized with the rotational position of the shaft of translational drive motor  1022 . 
     In one embodiment, components of the double-gear sliding collet-drive system  1000  contain longitudinal slits (not shown) to enable radial or side loading of EMD  1002  into collet lumen  1076 . 
     Robotic system  1000  in one embodiment includes a pinch/unpinch mode, a rotation mode and a translation mode. The pinch/unpinch mode, rotation mode and translation mode may occur individually or simultaneously. In one embodiment rotation mode and the translation mode occur simultaneously. 
     Referring to  FIG. 14A  one embodiment of a double-gear sliding collet-drive system with a reset mechanism is indicated. A disposable cassette  1080  is releasably mounted to a fixed base  1012  and includes the collet-and-rotational-drive system  1024  (described above) located distally and a reset mechanism  1082  located proximally. Reset mechanism  1082  (described below) is designed to advance, retract, and hold an EMD  1002 . Cassette  1080  includes a top cassette cover  1084  and a bottom cassette housing  1086 . In one embodiment cassette cover  1084  is connected to cassette housing  1086  by hinges at the back that allow the cover to rotate open and rotate close from the front. In one embodiment cassette cover  1084  is connected to cassette housing  1086  by hinges at the front that allow the cover to rotate open and rotate close from the back. In one embodiment cassette cover  1084  is connected to cassette housing  1086  by hinges that allow the cover to rotate open and close from the side. In one embodiment cassette cover  1084  is connected to cassette housing  1086  by fasteners that allow the cover to be opened and closed by rotation, by translation, or by a combination of rotation and translation relative to the housing  1086 . In one embodiment cassette cover  1084  is connected to cassette housing  1086  by press-fit features that allow the cover to be opened and closed by rotation, by translation, or by a combination of rotation and translation relative to the housing  1086 . In one embodiment cassette cover  1084  is connected to cassette housing  1086  by press-fit features that allow the cover to be removed from the housing  1086  and reseated to the housing  1086 . 
     The proximal and distal sides of the cassette cover  1084  include cover notches  1088  that allow for free passage of EMD  1002 . The proximal and distal sides of the cassette housing  1086  include housing notches  1090  that match the positions of cover notches  1088 . In one embodiment cover notches  1088  and housing notches  1090  are triangular-shaped cutouts that allow for free passage of EMD  1002 . In one embodiment cover notches  1088  and housing notches  1090  are arbitrarily shaped cutouts that allow for free passage of EMD  1002 . The underside of cassette cover  1084  includes cover ribs  1092 . When cassette cover  1084  is closed cover ribs  1092  seat EMD  1002  into alignment notches  1090  in cassette housing  1086  and maintain EMD  1002  vertical position in said alignment grooves or channels that maintain EMD  1002  lateral position. 
     As described above the collet-and-rotational-drive system  1024  is actuated by a first motor  1026  driving a first coupler  1030  and a second motor  1028  driving a second coupler  1032 . The reset mechanism  1082  is actuated by a reset mechanism motor  1094  that drives a reset mechanism coupler  1096 . In one embodiment reset mechanism motor  1094  is a stepper motor. In one embodiment reset mechanism motor  1094  is a servo motor. In one embodiment reset mechanism motor  1094  is a rotational actuator powered by electrical, pneumatic, hydraulic, or other means. 
     Referring to  FIG. 14B  the underside of fixed base  1012  is indicated. The reset mechanism  1082  is built into a reset mechanism frame  1098  that is integrally connected to fixed base  1012 . Reset mechanism coupler  1096  is integrally connected to a reset mechanism crank  1100  that can rotate relative to frame  1098  and base  1012 . In one embodiment reset mechanism coupler  1096  passes through a hole in reset mechanism frame  1098 . In one embodiment reset mechanism coupler  1096  passes through a rotational bearing that is mounted in reset mechanism frame  1098 . Reset mechanism crank  1100  is connected by a first revolute joint  1102  to a connecting link  1104 . Connecting link  1104  is connected by a second revolute joint  1106  to a cross-slider  1108 . Cross-slider  1108  is constrained to longitudinal translational motion (that is, translational motion only along the axis of EMD  1002 ) by a cross-slider first linear bearing  1110  and a cross-slider second linear bearing  1112 , both of which are integrally connected to cross-slider  1108 . First linear bearing  1110  is a prismatic joint that can translate relative to a first guide  1114  and second linear bearing  1112  is a prismatic joint that can translate relative to a second guide  1116 . The distal ends of first guide  1114  and second guide  1116  are integrally connected to fixed base  1012  and as such guides  1114  and  1116  are fixed. 
     A proximal first linear bearing  1118  and a distal first linear bearing  1120  are integrally mounted to the front corners of reset mechanism frame  1098 . A proximal second linear bearing  1122  and a distal second linear bearing  1124  are integrally mounted to the rear corners of reset mechanism frame  1098 . First guide  1114  can translate relative to proximal first linear bearing  1118  and distal first linear bearing  1120 . Second guide  1116  can translate relative to proximal second linear bearing  1122  and distal second linear bearing  1124 . Since the four bearings  1118 ,  1120 ,  1122 , and  1124  are integrally mounted to reset mechanism frame  1098 , reset mechanism  1082  can translate longitudinally relative to fixed base  1012 . 
     In one embodiment first coupler  1030  has a first coupler slotted end  1126  that seats into a slotted receiver of a shaft integrally connected to first driver bevel gear  1034  and second coupler  1032  has a second coupler slotted end  1128  that seats into a slotted receiver of a shaft integrally connected to second driver bevel gear  1042 . (See  FIG. 13C ) 
     Referring to  FIGS. 14C . 1 ,  14 C. 2 ,  14 C. 3 , and  14 C. 4  a sequence of steps indicates the operation of linear position mechanism  1082 , which includes a reset clamping cam  1130  that can rotate and a clamp support  1132  that is fixed. Reset cam  1130  rotates about a vertical axis by a reset cam coupler  1134 . In one embodiment reset cam coupler  1134  about which reset cam  1130  rotates is driven by a motor (not shown). In one embodiment reset cam coupler  1134  about which reset cam  1130  rotates is driven by a mechanism actuated by reset mechanism motor  1094 . In one embodiment reset cam coupler  1134  has a slotted end that seats in a receiver in cam  1130 . Reset cam  1130  has a curved outer surface  1136 . In one embodiment curved outer surface  1136  of reset cam  1130  has a convex geometry. In one embodiment curved outer surface  1136  of reset cam  1130  has a circular arc geometry. Holding cam  1132  has a curved outer surface  1138 . In one embodiment curved outer surface  1138  of holding cam  1132  has a convex geometry. In one embodiment curved outer surface  1138  of holding cam  1132  has a circular arc geometry. 
     In operation reset cam  1130  can be in a closed position or an open position. In the closed position reset cam  1130  is in an opposing position relative to holding cam  1132 . In one embodiment in the closed position there is no gap between reset cam outer surface  1136  and holding cam outer surface  1138  and the two surfaces  1136  and  1138  are in contact. In one embodiment in the closed position there is a gap between reset cam outer surface  1136  and holding cam outer surface  1138  with the gap distance less than the diameter of EMD  1002 . In the closed position EMD  1002  is pinched between reset cam outer surface  1136  and holding cam outer surface  1138 , such that EMD  1002  is prevented from translating longitudinally. In one embodiment reset cam outer surface  1136  and holding cam outer surface  1138  include an elastomeric or other deformable or compliant material that deforms about the EMD in the closed position. In the open position reset cam  1130  is rotated away from holding cam  1132  such that there is a gap between reset cam outer surface  1136  and holding cam outer surface  1138 . In the open position reset cam  1130  does not contact EMD  1002 , such that EMD  1002  is unconstrained to translate longitudinally at the location of holding cam  1132 . In one embodiment reset cam  1130  rotates 60 degrees away from holding cam  1132  in the open position. In one embodiment reset cam  1130  rotates less than 60 degrees away from holding cam  1132  in the open position. In one embodiment reset cam  1130  rotates more than 60 degrees away from holding cam  1132  in the open position. 
     Referring to  FIG. 14C . 1  the collet-and-rotational-drive system  1024  is pinching down on EMD  1002 , reset cam  1130  is in the open position, and cross-slider  1108  is in a proximal position relative to reset mechanism frame  1098 . As a result of this step, EMD  1002  is pinched in collet-and-rotational-drive system  1024 . 
     Referring to  FIG. 14C . 2  the collet-and-rotational-drive system  1024  is pinched on EMD  1002 , reset cam  1130  is in the open position, and cross-slider  1108  is translating distally from a proximal position relative to the reset mechanism frame  1098 . In one embodiment cross-slider  1108  is translating distally due to clockwise rotation of reset mechanism crank  1100  by reset mechanism motor  1094 . As a result of this step, collet-and-rotational-drive system  1024  advances distally, meaning EMD  1002  advances distally. 
     Referring to  FIG. 14C . 3  the collet-and-rotational-drive system  1024  is unpinching EMD  1002 , reset cam  1130  is in the closed position, and cross-slider  1108  is in its most distal position relative to reset mechanism frame  1098 . As a result of this step, EMD  1002  is unpinched in collet-and-rotational-drive system  1024 . 
     Referring to  FIG. 14C . 4  the collet-and-rotational-drive system  1024  is unpinched from EMD  1002 , reset cam  1130  is in the closed position, and cross-slider  1108  is translating proximally relative to reset mechanism frame  1098 . In one embodiment cross-slider  1108  is translating proximally due to counterclockwise rotation of reset mechanism crank  1100  by reset mechanism motor  1094 . As a result of this step, collet-and-rotational-drive system  1024  advances proximally and the system resets and can subsequently start over (to  FIG. 14C . 1 ). 
     Referring to  FIG. 17A  a single plunger collet system  1280  that can releasably engage an EMD includes a spring  1282  and a plunger  1284  that is movably positioned along a plunger axis  1286  within a receiving cavity  1288  of a housing  1290 . In the embodiment of  FIG. 17A  housing  1290  is a rectangular prism with a first lateral face  1292 , a second lateral face  1294 , and a convex top face  1296 . First lateral face  1292  is parallel to the plane defined by the plunger axis  1286  and an EMD axis  1298 . Second lateral face  1294  is parallel to the plane defined by the plunger axis  1286  and a perpendicular axis  1302 , where the perpendicular axis  1302  is perpendicular to the plunger axis  1286  and EMD axis  1298 . In one embodiment housing  1290  is a rectangular prism with the top face  1296  and opposite bottom face being rectangular planes. In one embodiment, the embodiment of  FIG. 18A , housing  1290  is a cylindrical disk with plunger axis  1286  aligned with a diametric axis of the disk, with the embodiment of  FIG. 17A  being a section removed from such a cylindrical disk. Referring to  FIGS. 18B and 18D  an outer housing  1291  is located about housings  1290 . Outer housing  1291  includes a plurality of cammed surfaces on an inner wall that operatively engage respective plungers  1284  as outer housing  1291  is rotated about its longitudinal axis relative to housings  1290 . In one embodiment the longitudinal axes of housings  1290  are co-linear with the longitudinal axis of outer housing  1291 . In one embodiment at least a portion of outer housing  1291  and/or a portion of housings  1290  is arcuate and/or circular. 
     First lateral face  1292  of housing  1290  has a slit  1300  oriented in the plane defined by EMD axis  1298  and perpendicular axis  1302  extending from face  1292  and terminating at EMD axis  1298  through housing  1290  from second lateral face  1294  to its opposite face. In one embodiment the walls of slit  1300  are parallel. In one embodiment the walls of slit  1300  are nonparallel, such as v-shaped walls with a vertex toward EMD axis  1298 . In one embodiment slit  1300  has a lead-in chamfer at first lateral face  1292 . In one embodiment slit  1300  has no lead-in chamfer at first lateral face  1292 . 
     Second lateral face  1294  of housing  1290  includes a plunger pin hole  1304  for a plunger pin  1306  (not shown in  FIG. 17A ) and a guide hole  1308  for an alignment pin (not shown). Plunger pin hole  1304  is aligned with a plunger pin axis  1307  parallel to EMD axis  1298  in the plane defined by the plunger axis  1286  and EMD axis  1298  extending through housing  1290  from second lateral face  1294  and terminating at the opposite outside face. Guide hole  1308  is aligned with an axis parallel to EMD axis  1298  in the plane defined by plunger axis  1286  and EMD axis  1298  extending through the housing wall from second lateral face  1294  and terminating at the opposite wall interior face of cavity  1288  in housing  1290 . In one embodiment guide hole  1308  is a well or cap hole in second lateral face  1294  and does not terminate at the opposite wall interior face of cavity  1288  in housing  1290 . In the embodiment of single plunger collet system  1280  in  FIG. 17A  guide hole  1308  is not needed. Guide hole  1308  is used for alignment of multi-plunger assemblies. 
     Referring to  FIG. 17B  plunger collet system  1280  is indicated in an unpinched configuration in which EMD  1314  is not operatively fixed to collet  1280 . An applied force  1310  acts on a top surface  1312  of plunger  1284  pushing plunger  1284  down in cavity  1288  of housing  1290 , compressing spring  1282  located below plunger  1284  with its long axis oriented along plunger axis  1286 . With plunger  1284  depressed fully into cavity  1288 , in one embodiment a bottom outer surface  1326  of plunger  1284  touches a lip  1328  in cavity  1288  of housing  1290 , thereby limiting further movement of plunger  1284 . With contact between surface  1326  and lip  1328  the plunger  1284  reaches its most depressed configuration in which spring  1282  is in its maximum compression state. In this case a plunger notch  1316  in plunger  1284  is furthest apart from a housing notch  1318  in housing  1290  and EMD  1314  can be moved into the open slit  1300  in the direction of plunger axis  1286 . In one embodiment plunger notch  1316  is a v-shaped channel or groove with its vertex pointed down. In one embodiment plunger notch  1316  is a well with its concavity pointed down. In one embodiment plunger notch  1316  is a generally downward depression with arbitrary geometry. In one embodiment housing notch  1318  is a v-shaped channel or groove with its vertex pointed up. In one embodiment housing notch  1318  is a well with its concavity pointed up. In one embodiment housing notch  1318  is a generally upward depression with arbitrary geometry. 
     With EMD  1314  fully inserted into the well of slit  1300  at plunger axis  1286 , applied force  1310  is removed. Referring to  FIG. 17C  plunger collet system  1280  is indicated in a pinched configuration in which EMD  1314  is not free to move relative to the collet, trapped between plunger notch  1316  and housing notch  1318  at the well of slit  1300  at plunger axis  1286  due to a restoring force  1320  from spring  1282  that pushes up on plunger  1284 . In the pinched configuration there is a gap between bottom outer surface  1326  of plunger  1284  and lip  1328  in cavity  1288  of housing  1290 . In addition, in the pinched configuration a portion  1322  of plunger  1284  protrudes outside of top face  1296  of housing  1290  and is exposed. 
     Referring to  FIG. 17B  and  FIG. 17C  plunger collet system  1280  is a normally closed collet, meaning without application of an applied force  1310  the collet is in a pinched configuration. 
     The bottom of compression spring  1282  is in contact with a bottom inner surface  1330  of cavity  1288  of housing  1290 . The top of compression spring  1282  is in contact with a bottom inner surface  1332  of plunger  1284 . In one embodiment at the bottom inner surface  1332  of plunger  1284  there is a pocket or cup that receives the top of spring  1282  and constrains the top of spring  1282  by lip  1328 . The outer diameter of spring  1282  is smaller than the inner diameter of cavity  1288  at the bottom of housing  1290  to allow freedom for compression. In one embodiment the outer diameter of spring  1282  is smaller than the inner diameter of cavity  1288  at the bottom of housing  1290  and larger than the diameter corresponding to buckling or bending of the spring to prevent buckling or bending of the spring. In one embodiment one compression spring  1282  is utilized. In one embodiment multiple springs, such as two nested springs, are used. 
     Plunger  1284  includes a plunger slot  1324  oriented along plunger axis  1286  allowing plunger  1284  to translate along plunger axis  1286  relative to housing  1290  constrained by plunger pin  1306  and the walls of the cavity  1288  in housing  1290 . To unpinch collet  1280  plunger  1284  is depressed down by application of applied force  1310  to the top surface  1312  of plunger. In operation plunger  1284  is a cam follower with its top surface  1312  being the follower surface in contact with a cam (not shown) pushing down on the cam follower with applied force  1310 . An outer member (not shown) with an internal cam is in contact with the top surface  1312  of plunger  1284 . By rotation of the outer member relative to housing  1290  the internal cam of the outer member pushes down on the top surface  1312  thereby depressing plunger  1284  and unpinching EMD  1314  in collet  1280 . 
     Referring to  FIG. 18A  a single plunger collet system  1280  operates with the same principle with housing  1290  being a circular disk with a center hole  1334  for EMD  1314  (not shown). The embodiment of  FIG. 18A  includes six guide holes  1308  arranged symmetrically about EMD axis  1298  at the same radial distance away from EMD axis  1298 . 
     Referring to  FIG. 18B  a multi-plunger collet system  1336  is indicated in an assembled configuration of six single plunger assemblies  1280 , each being the embodiment of  FIG. 18A , cascaded in series with each one progressively rotated relative to another about EMD axis  1298 . In one embodiment each of the six single plunger assemblies  1280  in the series is progressively rotated (that is, sequentially rotated in the same direction) by 60 degrees from one another such that guide holes  1308  are aligned. In this embodiment each single plunger assembly is rotated 60 degrees from assembly before it in the series. That is, if the first assembly is considered the reference at 0 degrees, the second assembly is rotated 60 degrees clockwise relative to the first assembly, the third assembly is rotated 120 degrees clockwise relative to the first assembly, the fourth assembly is rotated 180 degrees clockwise relative to the first assembly, the fifth assembly is rotated 240 degrees clockwise relative to the first assembly, and the sixth assembly is rotated 300 degrees clockwise relative to the first assembly. Thus, the plungers of the first and fourth assemblies are in opposite directions (180 degrees apart), the plungers of the second and fifth assemblies are in opposite directions (180 degrees apart), and the plungers of the third and sixth assemblies are in opposite directions (180 degrees apart). 
     Referring to  FIG. 18C  a multi-plunger collet system  1336  is indicated in the assembled configuration shown in  18 B with the first single plunger assembly  1280  separated off. Again, system  1336  includes six single plunger assemblies ( 1280 ), each being the embodiment of  FIG. 18A , cascaded in series with each one progressively rotated by 60 degrees about EMD axis  1298  relative to the assembly before it. 
     Referring to  FIG. 18D  the end view of the assembled multi-plunger system  1336  of  FIG. 18B  is indicated with solid lines for the first single plunger assembly  1280  and phantom lines for the second through sixth single plunger assemblies  1280  with each single plunger assembly progressively rotated by 60 degrees about EMD axis  1298  relative to the assembly before it such that the guide holes  1308  align. The three visible single plunger assemblies correspond to the first and fourth assemblies, the second and fifth assemblies, and the third and sixth assemblies, with each pair being in opposite directions (180 degrees apart). The center hole  1334  of the six single plunger assemblies  1280  align for axial loading of EMD  1314 . In one embodiment six single plunger assemblies  1280  are used each progressively rotated by 60 degrees about EMD axis  1298  relative to the assembly before it. In one embodiment four single plunger assemblies  1280  are used each progressively rotated by 90 degrees about EMD axis  1298  relative to the assembly before it. In one embodiment three single plunger assemblies  1280  are used each progressively rotated by 120 degrees about EMD axis  1298  relative to the assembly before it. In one embodiment two single plunger assemblies  1280  are used with the second assembly rotated by 180 degrees about EMD axis  1298  relative to the first assembly. In one embodiment two single plunger assemblies  1280  are used with the second assembly rotated by less than 180 degrees about EMD axis  1298  relative to the first assembly. In one embodiment two single plunger assemblies  1280  are used with the second assembly rotated by more than 180 degrees about EMD axis  1298  relative to the first assembly. In one embodiment more than two single plunger assemblies  1280  are used each progressively rotated by an arbitrary number of degrees about EMD axis  1298  relative to the assembly before it. In an example of this embodiment using four single plunger assemblies  1280  if the first assembly is considered the reference at 0 degrees, the second assembly is rotated 45 degrees clockwise relative to the first assembly, the third assembly is rotated 135 degrees clockwise relative to the first assembly, and the fourth assembly is rotated 180 degrees clockwise relative to the first assembly. This embodiment allows radial loading of an EMD within the collet. In one embodiment the single plunger assemblies  1280  of the multi-plunger collet system are identical. In one embodiment the single plunger assemblies  1280  of the multi-plunger collet system are not identical. 
     Referring to  FIG. 18E  the unpinched configuration of a multi-plunger collet system  1336  with six single plunger assemblies  1280  requires an external applied force  1310  applied to each plunger  1284  from an outer member cam (not shown). In the unpinched configuration there is no contact of EMD  1314  between the plunger and housing at any single plunger assembly  1280  in the multi-plunger system  1336 . 
     Referring to  FIG. 18F  the pinched configuration of a multi-plunger collet system  1336  with six single plunger assemblies  1280  is indicated. In the pinched configuration there is contact of EMD  1314  between the plunger and housing at each single plunger assembly  1280  in the multi-plunger system  1336  due to reaction force  1320  from each compression spring  1282 . Being that each single plunger assembly  1280  is sequentially rotated relative to the assembly before it, contact on EMD  1314  occurs at different surfaces giving more torque capability of the collet system  1336 . In the embodiment of  FIG. 18F  contact occurs at a portion of the bottom surface  1338  of EMD  1314  in the first single plunger assembly  1280  (shown at left) and contact occurs at a portion of the top surface  1340  of EMD  1314  in the fourth (from left) single plunger assembly  1280 . Contact at different surface portions of EMD  1314  occurs at each single plunger assembly  1280  meaning there is contact at different portions longitudinally along the EMD. 
     Referring to  FIGS. 18G, 18H, and 18I  a multi-plunger collet system  1336  in the pinched configuration with six single plunger assemblies  1280  is indicated with EMD  1314  in a side view and a front view. Referring to  FIG. 18G  a multi-plunger collet system  1336  with six single plunger assemblies  1280  all oriented in the same direction is indicated. The side view of EMD  1314  is a straight line and the front view of EMD  1314  is a single point. Referring to  FIG. 18H  a multi-plunger collet system  1336  with six single plunger assemblies  1280  each oriented 180 degrees apart from the assembly before it is indicated. The side view of EMD  1314  is an approximately sinusoidal line in a plane and the front view of EMD  1314  is a single point moving up and down along a vertical line. Referring to  FIG. 18I  a multi-plunger collet system  1336  with six single plunger assemblies  1280  each progressively oriented 60 degrees apart from the assembly before it is indicated. The side view of EMD  1314  is an approximately sinusoidal line in a plane and the front view of EMD  1314  is a single point moving along the circumference of a circle. 
     Compared to the torque carrying ability of the multi-plunger collet system  1336  of  FIG. 18G  when pinched, the torque carrying ability of the multi-plunger collet system  1336  of  FIG. 18H  when pinched is increased. Due to the 180 degree offsets of the single plunger assemblies  1280  in the multi-plunger collet system of  FIG. 18H  the EMD  1314  adopts a tortuous configuration that goes up and down in a side view with the top and bottom of the vertical line in a front view having the most resistive torque (with the neutral device axis being in the center of the line). Compared to the torque carrying ability of the multi-plunger collet system  1336  of  FIG. 18H  when pinched, the torque carrying ability of the multi-plunger collet system  1336  of  FIG. 18I  when pinched is further increased. Due to the 60 degree offsets of the single plunger assemblies  1280  in the multi-plunger collet system of  FIG. 18H  the EMD  1314  adopts a configuration that has a spiral path, that is, helix shape, with the EMD always away from the central axis  1298  of the EMD giving the most resistive torque. 
     The deformation of the EMD  1314  in the pinched configuration of the multi-plunger collet system  1336  is a function of the through hole diameter in the center of the plunger housing, the gap (clearance) between the plunger and plunger housing, and the force applied by the spring mechanism. 
     In one embodiment a series of pinching elements in a collet for robotic actuation where the pinching elements are independently actuated. The actuation mechanism such as a cam is such that instead of actuating all of the elements together, their actuation is not all together such as sequentially actuated. This feature acts to lower actuation force. 
     In one embodiment multi-plunger collet system  1336  consisting of multiple pinching elements are rotationally clocked to each other in order to increase the overall torque holding capability of the collet. Rotationally clocked refers to placing the pinching elements at various angles in a plane perpendicular to the longitudinal axis of the collet  1336 . 
     Referring to  FIG. 18B  collet  1336  includes an inner member that defines a pathway receiving an EMD  1314  and an outer member a plurality of engagement members  1284  releasably engaging EMD  1314  as the inner member is moved relative to the outer member. In one embodiment a spring  1282  biases engagement member  1284 . In one embodiment spring  1282  biases engagement member  1284  away from the pathway in one embodiment spring  1282  biases engagement member  1284  toward the pathway. In one embodiment engagement members  1284  are normally closed or located within the pathway and require to be moved to an open position to insert an EMD. In one embodiment engagement members  1284  are normally open or located outside of the pathway and require to be moved to a closed position to engage the EMD. In one embodiment engagement members  1284  sequentially engage the EMD. Referring to  FIG. 18I  in one embodiment engagement members  1284  are offset circumferentially about the EMD. Referring to  FIG. 18G  in one embodiment engagement members  1284  are offset axially. Referring to  FIG. 18H  in one embodiment a first engagement member is positioned 180 degrees from a second engagement member. In one embodiment engagement members  1284  are independent and not directly connected to one another. In one embodiment movement of the inner member relative to the outer member is rotational. In one embodiment movement of the inner member relative to the outer member is translational. In one embodiment the movement of the inner member and outer member relative to one another is robotic. In one embodiment movement of the inner member and outer member relative to one another is manual. Referring to  FIGS. 18H and 18I  in one embodiment engagement members  1284  are offset radially about the EMD forming a tortuous path. Referring to  FIG. 18H  in one embodiment the tortuous path is in a single plane. Referring to  FIG. 18I  in one embodiment the tortuous path is not in a single plane. 
     Referring to  FIGS. 19A, 19B, 19C, and 19E  an opposing pad collet system  1360  that can releasably engage an EMD  1388  includes an inner housing  1362 , an outer housing  1363 , a plurality of springs  1364   a,b,c , . . . , a plurality of levers  1366   a,b,c , . . . , and a pivot pin  1368 . In one embodiment inner housing  1362  of collet system  1360  is in the shape of a right circular cylinder with its longitudinal axis oriented along the EMD axis  1370 . Inner housing  1362  includes an internal cavity  1372 , a radial longitudinal slit  1374 , and a plurality of circumferential slits  1376   a,b,c , . . . . In one embodiment outer housing  1363  is in the shape of a right circular cylinder with its longitudinal axis oriented along the EMD axis  1370 . Outer housing  1363  includes a radial longitudinal slit  1367 , an internal cavity  1369 , and a plurality of cam surfaces  1365   a,b,c , . . . on the inner surface (interior wall) of outer housing  1363 . In one embodiment the outer housing  1363  is a cylindrical tube with a wall thickness greater than 10 percent of the inner diameter with a plurality of cam surfaces  1365   a,b,c , . . . on the inner surface. In one embodiment the outer housing  1363  is a cylindrical tube with a wall thickness less than 10 percent of the inner diameter with a plurality of cam surfaces  1365   a,b,c , . . . on the inner surface. (Referring to  FIGS. 19A-19G  the wall thicknesses of outer housing  1363  are representative. Note that the geometry of outer housing  1363  in  FIG. 19A  differs from the representative cross-section of  FIG. 19B-19G .) The outer diameter of inner housing  1362  is smaller than the diameter of the internal cavity  1369  of outer housing  1363  such that in the assembled embodiment inner housing  1362  is located interior to outer housing  1363 . 
     In one embodiment the longitudinal axis of inner housing  1362  is co-linear with the longitudinal axis of outer housing  1363 . In one embodiment at least a portion of outer housing  1363  and/or a portion of inner housing  1362  is arcuate and/or circular. In one embodiment all levers  1366   a,b,c , . . . rotate about a single pivot pin  1368 . In one embodiment multiple pivot pins  1368   a,b,c , . . . are used, where lever  1366   a  rotates about pin  1368   a , lever  1366   b  rotates about pin  1368   b , etc. In one embodiment the plurality of cam surfaces  1365   a,b,c , . . . are incrementally spaced along a longitudinal axis around the inner circumference of outer housing  1363 . In one embodiment the plurality of cam surfaces  1365   a,b,c , . . . are grooves or recesses incrementally spaced along a longitudinal axis around the inner circumference of outer housing  1363 . 
     Circumferential slits  1376   a,b,c , . . . of inner housing  1362  are oriented parallel to a plane perpendicular to EMD axis  1370 . In the embodiment of  FIG. 19A  nine circumferential slits  1376   a,b,c, . . . , i  are indicated in which nine arms  1384   a,b,c , . . . i of levers  1366   a,b,c, . . . i  are correspondingly exposed. In other embodiments a different number of circumferential slits is used with a corresponding number of arms exposed. For example, in one embodiment one circumferential slit  1376   a  is used in which arm  1384   a  of lever  1366   a  is exposed. In one embodiment two circumferential slits  1376   a,b  are used in which arms  1384   a,b  of levers  1366   a,b  are correspondingly exposed. In one embodiment more than one circumferential slit  1376  is used. In one embodiment circumferential slits  1376   a,b,c , . . . extend radially inward from an outer surface of inner housing  1362  through to internal cavity  1372  of inner housing  1362 . In one embodiment circumferential slits  1376   a,b,c , . . . extend radially inward from an outer surface of inner housing  1362  through to the interior of inner housing  1362  that is not part of cavity  1372 . In one embodiment circumferential slits  1376   a,b,c , . . . extend radially inward from an outer surface of inner housing  1362  through to the internal cavity  1372  of inner housing  1362  and through to the interior of inner housing  1362  that is not part of cavity  1372 . In one embodiment the walls of slits  1376   a,b,c , . . . are parallel. In one embodiment the walls of circumferential slits  1376   a,b,c , . . . are nonparallel. In one embodiment circumferential slits  1376   a,b,c , . . . have lead-in chamfers at the outer surface of inner housing  1362 . In one embodiment circumferential slits  1376   a,b,c , . . . have no lead-in chamfers at the outer surface of inner housing  1362 . 
     Radial longitudinal slit  1367  of outer housing  1363  extends from an outer surface of outer housing  1363  and terminates at inner surface of internal cavity  1369  of outer housing  1363 . The gap between the walls of radial longitudinal slit  1367  is larger than the diameter of an EMD  1388  allowing an EMD  1388  to enter. In one embodiment the walls of radial longitudinal slit  1367  are parallel. In one embodiment the walls of radial longitudinal slit  1367  are nonparallel, such as v-shaped walls with a vertex toward EMD axis  1370 . In one embodiment radial longitudinal slit  1367  has a lead-in chamfer at the outer surface of outer housing  1363 . In one embodiment radial longitudinal slit  1367  has no lead-in chamfer at the outer surface of outer housing  1363 . 
     Radial longitudinal slit  1374  of inner housing  1362  extends from an outer surface of inner housing  1362  and terminates at its radial center corresponding to EMD axis  1370  and extends longitudinally through inner housing  1362 . The gap distance between the walls of radial longitudinal slit  1374  is larger than the diameter of an EMD  1388  allowing an EMD  1388  to enter. In one embodiment the walls of radial longitudinal slit  1374  are parallel. In one embodiment the walls of radial longitudinal slit  1374  slits are nonparallel, such as v-shaped walls with a vertex toward EMD axis  1370 . In one embodiment radial longitudinal slit  1374  has a lead-in chamfer at the outer surface of inner housing  1362 . In one embodiment radial longitudinal slit  1374  has no lead-in chamfer at the outer surface of inner housing  1362 . 
     Springs  1364   a,b,c , . . . are compression springs, such as coil springs, located in the internal cavity  1372  of inner housing  1362 . One end of springs  1364   a,b,c , . . . is constrained by an internal wall  1378  of cavity  1372  of inner housing  1362 . The other end of springs  1364   a,b,c , . . . is seated over and extends into protrusions  1380   a,b,c , . . . of levers  1366   a,b,c , . . . . In one embodiment protrusions  1380   a,b,c , . . . of levers  1366   a,b,c , . . . extend into one end coil of springs  1364   a,b,c , . . . . In one embodiment protrusions  1380   a,b,c , . . . of levers  1366   a,b,c , . . . extend into more than one end coil of springs  1364   a,b,c , . . . . In one embodiment protrusions  1380   a,b,c , . . . of levers  1366   a,b,c , . . . are operatively connected to one end coil of springs  1364   a,b,c , . . . . In one embodiment protrusions  1380   a,b,c , . . . of levers  1366   a,b,c , . . . are operatively connected to more than one end coil of springs  1364   a,b,c , . . . . In one embodiment one compression spring  1364  is used. In one embodiment multiple compression springs are used. In one embodiment, the number of springs equals the number of levers. In one embodiment a collar or sleeve surrounding each spring  1364   a,b,c , . . . is used to prevent buckling or bending of the springs. 
     In the assembled configuration springs  1364   a,b,c , . . . are in compression. In operation, cam surfaces  1365   a,b,c , . . . on the inner surface (interior wall) of outer housing  1363  operatively engage respective arms  1384   a,b,c , . . . of levers  1366   a,b,c , . . . that are exposed in slits  1376   a,b,c , . . . as outer housing  1363  is rotated about its longitudinal axis relative to inner housing  1362 . Referring to  FIG. 19B  opposing pad collet system  1360  is indicated in an unpinched configuration in which EMD  1388  is not operatively fixed to collet  1360 . In this configuration radial longitudinal slit  1367  of outer housing  1363  is aligned with radial longitudinal slit  1374  of inner housing. An applied force  1382   a  acts on arm  1384   a  of lever  1366   a  such that lever  1366   a  is rotated counterclockwise about pivot pin  1368  with spring  1364   a  in cavity  1372  of inner housing  1362  under compression. Due to the position of lever  1366   a , pad  1386   a  of lever  1366   a  is oriented away from EMD axis  1370  and from radial longitudinal slit  1374  near EMD axis  1370 . In this unpinched configuration EMD  1388  can be moved into the radial longitudinal slit  1367  and into radial longitudinal slit  1374  in the direction of EMD axis  1370 . In one embodiment outer housing  1363  is rotated relative to inner housing  1362  by an actuator (not shown). The actuator rotating outer housing  1363  relative to inner housing  1362  in one embodiment is in the drive module and in one embodiment is in the cassette. 
     To pinch and unpinch opposing pad collet system  1360  lever  1366   a  pivots about pivot pin  1368  through a limited range of motion. In one embodiment the angular range of motion of lever  1366   a  is less than 10 degrees. In one embodiment the angular range of motion is greater than 10 degrees. Lever  1366   a  acts as a first-class lever with its pivot between an effort and a load. An effort or input force  1382   a  is applied to an arm  1384   a  of lever  1366   a . A load or output force acts at pad  1386   a  of lever  1366   a.    
     With EMD  1388  fully inserted into radial longitudinal slit  1374 , applied force  1382   a  is removed. Referring to  FIG. 19C  opposing pad collet system  1360  is indicated in a pinched configuration in which EMD  1388  is not free to move relative to the collet, trapped between pad  1386   a  and a wall of radial longitudinal slit  1374  due to a restoring force  1390   a  from spring  1364   a  that pushes up on arm  1384   a  of lever  1366   a . In one embodiment in the pinched configuration the outside end of arm  1384   a  protrudes into the circumferential slit  1376   a  of inner housing  1362  and is exposed. 
     Referring to  FIG. 19B  and  FIG. 19C  opposing pad collet system  1360  is a normally closed collet, meaning without application of an applied force  1382   a  the collet is in a pinched configuration. 
     In operation arm  1384   a  of lever  1366   a  is a cam follower with an outer surface of arm  1384   a  being the follower surface in contact with a cam (inner surface of outer housing  1363 ) pushing on the cam follower with applied force  1382   a . Outer member  1363  with an internal cam is in contact with the outer surface of arm  1384   a . By rotation of the outer housing  1363  relative to inner housing  1362  the internal cam of the outer member pushes on the outer surface of arm  1384   a , exposed in circumferential slit  1376   a , thereby rotating lever  1366   a  and moving pad  1386   a  of lever  1366   a  away from EMD axis  1370  and unpinching EMD  1388  in collet  1360 . In one embodiment with a single circumferential slit  1376   a  the cam includes a finger or tab that presses against the outer surface of arm  1384   a . In one embodiment with multiple circumferential slits  1376   a,b,c , . . . the cam includes multiple fingers or tabs that press against outer surfaces of multiple arms  1384   a,b,c , . . . . In one embodiment multiple levers  1366   a,b,c , . . . are used with their pads  1386   a,b,c , . . . pinching the EMD  1388  at multiple locations longitudinally. In one embodiment contact of the EMD  1388  occurs between the pad  1386   a  of a single lever  1366   a  along the length of the collet system. 
     Referring to  FIGS. 19D-19G  the sequence of incremental pinching of opposing pad collet system  1360  is indicated. (In the figures on the right springs  1364   a,b,c , . . . are present but not shown; in the figures on the left springs  1364   a,b,c , . . . are not numbers but indicated by lightly dashed circles.) Referring to  FIG. 19D , the opposing pad collet system  1360  is indicated in an unpinched configuration for radial loading of EMD  1388 . There is no contact of pads  1386   a,b,c , . . . with EMD  1388  since inner wall of outer housing  1363  maintains arms  1384   a,b,c , . . . of levers  1366   a,b,c , . . . in a configuration that compresses springs  1364   a,b,c , . . . in the maximum compressive state during operation. Referring to  FIG. 19E , a first increment of rotation (corresponding to one clockwise arrow) of outer housing  1363  relative to inner housing  1362  corresponds to engagement of pad  1386   a  of lever  1366   a  with EMD  1388  as a result of rotation of lever  1366   a  due to the recess of cam  1365   a  on the inner surface of outer housing  1363 . Spring  1364   a  is slightly relaxed from its maximum compressive state and is the source of the force between pad  1386   a  and EMD  1388 . In this first increment of rotation all other pads  1386   b,c , . . . of levers  1366   b,c , . . . remain in the unpinched configuration. In this first increment of rotation it is not possible for EMD  1388  to be removed from opposing pad collet system  1360  since radial longitudinal slit  1367  of outer housing  1363  is not aligned with radial longitudinal slit  1374  of inner housing  1362 . Referring to  FIG. 19F , a second increment of rotation (corresponding to two clockwise arrows) of outer housing  1363  relative to inner housing  1362  corresponds to engagement of pads  1386   a  and  1386   b  with EMD  1388  as a result of rotation of levers  1366   a  and  1366   b  due to the recesses of cams  1365   a  and  1365   b  on the inner surface of outer housing  1363 . Springs  1364   a  and  1364   b  are slightly relaxed from their maximum compressive state and are the source of the force between pads  1386   a  and  1386   b  and EMD  1388 . In this second increment of rotation all other pads  1386   c,d , . . . of levers  1366   c,d , . . . remain in the unpinched configuration. Referring to  FIG. 19G , a third increment of rotation (corresponding to three clockwise arrows) of outer housing  1363  relative to inner housing  1362  corresponds to engagement of pads  1386   a,b,c  with EMD  1388  as a result of rotation of levers  1366   a,b,c  due to the recesses of cams  1365   a,b,c  on the inner surface of outer housing  1363 . Springs  1364   a,b,c  are slightly relaxed from their maximum compressive state and are the source of the force between pads  1386   a,b,c  and EMD  1388 . In this third increment of rotation all other pads  1386   d,e , . . . of levers  1366   d,e , . . . remain in the unpinched configuration. (Note: In  FIGS. 19E-19G  the EMD  1388  is illustrated with an exaggerated bias in the places where there is engagement.) 
     In one embodiment rotation of 20 degrees of outer housing  1363  relative to inner housing  1362  corresponds to an increment of rotation for engagement of a pad  1386   a,b,c , . . . of corresponding lever  1366   a,b,c , . . . with EMD  1388 . In one embodiment rotation of less than 20 degrees of outer housing  1363  relative to inner housing  1362  corresponds to an increment of rotation for engagement of a pad  1386   a,b,c , . . . of corresponding lever  1366   a,b,c , . . . with EMD  1388 . In one embodiment rotation of more than 20 degrees of outer housing  1363  relative to inner housing  1362  corresponds to an increment of rotation for engagement of a pad  1386   a,b,c , . . . of corresponding lever  1366   a,b,c , . . . with EMD  1388 . 
     Referring to  FIG. 20A , a collet-drive system  1500  that can rotate, translate, and pinch an EMD  1502  includes a collet  1504 , a collet engagement member  1506 , a first drive module  1508 , and a second drive module  1510 . Collet-drive system  1500  may also be referred to as a quick release collet with two linear drives and axial spline engagement. 
     Collet  1504  has a collet first member  1512  that has a first engagement portion  1514 . Collet  1504  has a collet second member  1516  that is driven. 
     Collet engagement member  1506  has a second engagement portion  1518 . 
     Collet first member  1512  and collet engagement member  1506  move between an engaged position and a disengaged position. Referring to  FIG. 20C  collet first member  1512  and collet engagement member  1506  are indicated in a disengaged position. 
     First engagement portion  1514  engages second engagement portion  1518  as collet first member  1512  and collet engagement member  1506  are moved to the engaged position. Referring to  FIGS. 20C-20G  collet first member  1512  and collet engagement member  1506  are indicated in an engaged position. 
     Rotation of collet first member  1512  with respect to collet second member  1516  in a first direction  1520  in the engaged position pinches an EMD  1502  within the collet  1504  and rotation of collet first member  1512  with respect to collet second member  1516  in a second direction  1522  opposite the first direction  1520  unpinches the EMD  1502  within the collet  1504 . 
     In collet-drive system  1500  the first engagement portion  1514  includes a plurality of splines that extend circumferentially about at least a portion of the collet first member  1512 . The second engagement portion  1518  includes a plurality of members operatively engaging the plurality of splines of the first engagement portion  1514 . 
     In one embodiment collet second member  1516  is connected to a bevel gear  1524  that meshes with and is driven by a capstan bevel gear  1526 . In one embodiment collet second member  1516  is driven by a coupler. 
     In one embodiment the plurality of splines of first engagement portion  1514  includes external spline teeth that extend longitudinally. In one embodiment the plurality of members of second engagement portion  1518  includes internal spline teeth that extend longitudinally and mesh with the external spline teeth that extend longitudinally of the plurality of splines of first engagement portion  1514 . 
     Collet engagement member  1506  is integrally connected to first drive module  1508  and oriented such that its centerline is aligned longitudinally with the axis of EMD  1502 . 
     First drive module  1508  and second drive module  1510  translate longitudinally relative to a fixed lead screw  1528  (illustrated as reference  76  in  FIG. 3 ) and are driven independently by a first actuator  1530  and a second actuator  1532  (identified as translation motors  64  in  FIG. 3 ), respectively. In one embodiment lead screw  1528  is a ball screw. In one embodiment, first drive module  1508  and second drive module  1510  are driven independently by belt drives. In one embodiment first actuator  1530  is a motor powered by electrical, pneumatic, hydraulic, or other means. In one embodiment second actuator  1532  is a motor powered by electrical, pneumatic, hydraulic, or other means. 
     Referring to  FIG. 20A  collet-drive system  1500  is connected to the overall robotic system  24 . In particular, the connections of lead screw  1528 , first actuator  1530 , second actuator  1532 , first drive module  1508 , and second drive module  1510  to the overall robotic system is illustrated. 
     In one embodiment translation of first drive module  1508  is accomplished as follows. A drive shaft of first actuator  1530  is integrally connected to a first actuation pulley  1534  that drives a first belt  1536  that drives a first nut pulley  1538  that is integrally connected to a first nut-bearing assembly  1540  that meshes with lead screw  1528  and is integrally connected to first drive module  1508 . Similarly, in one embodiment translation of second drive module  1510  is accomplished as follows. A drive shaft of second actuator  1532  is integrally connected to a second actuation pulley  1544  that drives a second belt  1546  that drives a second nut pulley  1548  that is integrally connected to a second nut-bearing assembly  1550  that meshes with lead screw  1528  and is integrally connected to second drive module  1510 . 
     First drive module  1508  includes a clamp and rotational drive mechanism that acts both to clamp/unclamp an EMD as well as to translate the EMD along its longitudinal axis. In one embodiment the clamp and rotational drive mechanism includes drive tire  1558  and an idler tire  1568 . In one embodiment drive tire  1558  is driven as follows. A driver gear  1552  meshes with a drive tire gear  1554  that is integrally connected to a drive tire capstan  1556  that is integrally connected to drive tire  1558 . It is contemplated that other clamp and translational devices known in the art may be employed as well. 
     Referring to  FIGS. 20A and 20B  in one embodiment driver gear  1552  is driven by a third actuator  1560  that is incorporated internal to first drive module  1508 . In one embodiment third actuator  1560  is a motor powered by electrical, pneumatic, hydraulic, or other means. 
     In one embodiment rotation of driver gear  1552  is accomplished as follows. A drive shaft of third actuator  1560  is integrally connected to a third actuation pulley  1562  (supported by a bearing) that drives a second belt  1564  that drives a driver gear pulley  1566  (supported by a bearing) that is integrally connected to driver gear  1552 . 
     First drive module  1508  includes a straddle rocker  1570  and a spring  1572 . Straddle rocker  1570  rotates about a pivot  1574  that is parallel to the axis of drive tire  1558  and idler tire  1568 . Spring  1572  is a tension spring with one end connected to a rocker distal post  1575  integrally connected to straddle rocker  1570  and one end connected to a driver gear extension post  1576  that extends from driver gear  1552 . Straddle rocker  1570  is a spring-loaded bell crank, that is, a spring-loaded lever with two arms and pivot  1574 . One arm of straddle rocker  1570  is integrally connected to rocker distal post  1575  at its free end. One arm of straddle rocker  1570  supports idler tire  1568  at its free end. 
     Second drive module  1510  includes driven capstan bevel gear  1526  and capstan  1527 . Capstan bevel gear  1526  is integrally connected to capstan  1527  that is driven by an actuator (not shown). Second drive module  1510  is integrally connected to an extension link  1578  that extends out from the far end (that is, end farthest from lead screw  1528 ) of second drive module  1510  in a direction toward first drive module  1508  and parallel to lead screw  1528  and to EMD  1502 . In one embodiment extension link  1578  is a rectangular bar with its length greater than its width and its width greater than its height (thickness). Extension link  1578  includes a first lip  1580  and a second lip  1581 . In one embodiment first lip  1580  and second lip  1581  are rectangular bar projections, like flanges, oriented up and perpendicular to extension link  1578 . In one embodiment first lip  1580  is located at the proximal end of extension link  1578  and second lip  1581  is located near the proximal end of extension link  1578  such that there is a gap between the inside faces of first lip  1580  and second lip  1581 . 
     In one embodiment collet-drive system  1500  includes a cassette (not shown) that includes collet  1504 , collet engagement member  1506 , drive tire  1558 , and idler tire  1568 . 
     Operation of collet-drive system  1500  consists of multiple states, as described herein. 
     Referring to  FIG. 20C  collet-drive system  1500  is indicated in a driving state (first state). In the driving state collet  1504  pinches EMD  1502 , collet  1504  rotates EMD  1502 , first drive module  1508  and second drive module  1510  move together maintaining the same separation distance, the spline teeth of first engagement portion  1514  and second engagement portion  1518  do not mesh (that is, are not engaged), and drive tire  1558  and idler tire  1568  are separated and do not grip EMD  1502 . In the driving state rocker distal post  1575  is in contact with the inside face of first lip  1580  and straddle rocker  1570  is positioned to keep idler tire  1568  separated from drive tire  1558 . 
     Referring to  FIG. 20D  collet-drive system  1500  is indicated in a collet lock state (second state). In the collet lock state collet  1504  pinches EMD  1502 , first drive module  1508  and second drive module  1510  move toward one another reducing their separation distance (for example, second drive module  1510  moves toward a fixed first drive module  1508 ), the spline teeth of first engagement portion  1514  mesh with spline teeth of second engagement portion  1518  (that is, they are engaged, although not fully), and drive tire  1558  and idler tire  1568  are slightly separated from one another and do not grip EMD  1502 . In the collet lock state rocker distal post  1575  is in contact with the inside face of first lip  1580  and straddle rocker  1570  rotates moving idler tire  1568  toward drive tire  1558  but the tires do not grip EMD  1502 . 
     Referring to  FIG. 20E  collet-drive system  1500  is indicated in a device exchange state (second alternate state). In the device exchange state collet  1504  unpinches EMD  1502 , first drive module  1508  and second drive module  1510  move toward one another reducing their separation distance (the same as the collet lock state), the spline teeth of first engagement portion  1514  mesh with spline teeth of second engagement portion  1518  (that is, they are engaged, although not fully), and drive tire  1558  and idler tire  1568  are separated from one another and do not grip EMD  1502 . In the exchange state, just as in the collet lock state, rocker distal post  1575  is in contact with the inside face of first lip  1580  and straddle rocker  1570  rotates moving idler tire  1568  toward drive tire  1558  but the tires do not grip EMD  1502 . 
     In the exchange state collet  1504  unpinches EMD  1502  by rotation of capstan bevel gear  1526  that meshes and rotates driven bevel gear  1524  that rotates collet second member  1516  relative to collet first member  1512 . Note that collet first member  1512  is locked (does not move) due to engagement of spline teeth of first engagement portion  1514  with spline teeth of second engagement portion  1518  that does not move. With collet  1504  in an unpinched state EMD  1502  can be removed. In one embodiment EMD  1502  can be removed by side or radial unloading with alignment of a collet slit  1582  in collet  1504  and a collet engagement member slit  1584  in collet engagement member  1506 . In one embodiment EMD  1502  can be removed by axial unloading. 
     Referring to  FIG. 20A  collet slit  1582  extends longitudinally from an outer circumferential surface and extends radially through collet  1504  to its center line and collet engagement member slit  1584  extends longitudinally from an outer surface circumferential and extends radially through collet engagement member  1506  to its center line. In one embodiment slits  1582  and  1584  have parallel walls. In one embodiment slits  1582  and  1584  have nonparallel walls, such as v-shaped walls with the vertex toward the radial center. In one embodiment slits  1582  and  1584  have lead-in chamfers at the outer surface. In one embodiment slits  1582  and  1584  have no chamfers at the outer surface. 
     Referring to  FIG. 20F  collet-drive system  1500  is indicated in a collet pinched-tire grip state (third state). In the collet pinched-tire grip state collet  1504  pinches EMD  1502 , first drive module  1508  and second drive module  1510  move toward one another to their smallest separation distance (for example, second drive module  1510  moves toward a fixed first drive module  1508 ), the spline teeth of first engagement portion  1514  fully mesh with spline teeth of second engagement portion  1518  (that is, they are engaged fully), and drive tire  1558  and idler tire  1568  are not separated and grip EMD  1502 . In the collet pinched-tire grip state rocker distal post  1575  is in contact with the inside face of second lip  1581  and straddle rocker  1570  rotates moving idler tire  1568  into drive tire  1558  such that the tires grip EMD  1502 . 
     Referring to  FIG. 20G  collet-drive system  1500  is indicated in a tire driving state (fourth state). In the tire driving state collet  1504  unpinches EMD  1502 , first drive module  1508  and second drive module  1510  move toward one another to their smallest separation distance (for example, second drive module  1510  moves toward a fixed first drive module  1508 ), the spline teeth of first engagement portion  1514  fully mesh with spline teeth of second engagement portion  1518  (that is, they are engaged fully), and drive tire  1558  and idler tire  1568  are not separated and grip EMD  1502 . In the tire driving state, as in the collet pinched-tire grip state, rocker distal post  1575  is in contact with the inside face of second lip  1581  and straddle rocker  1570  rotates moving idler tire  1568  into drive tire  1558  such that the tires grip EMD  1502 . 
     In the tire driving state collet  1504  unpinches EMD  1502  by rotation of capstan bevel gear  1526  that meshes and rotates driven bevel gear  1524  that rotates collet second member  1516  relative to collet first member  1512 . Note that collet first member  1512  is locked (does not move) due to engagement of spline teeth of first engagement portion  1514  with spline teeth of second engagement portion  1518  that does not move. With collet  1504  in an unpinched state EMD  1502  can be translated by rotation of drive tire  1558  gripping EMD  1502  against idler tire  1568 . 
     Collet drive system  1500  operates in a reset mode or in an exchange mode. In the reset mode the sequence for operation is driving state (first state), collet lock state (second state), collet pinched-tire grip state (third state), tire driving state (fourth state), collet pinched-tire grip state (third state), collet lock state (second state), and back to driving state (first state). In the exchange mode the sequence of operation is driving state (first state), collet lock state (second state), device exchange state (second alternate state), collet lock state (second state), and back to driving state (first state). 
     Collet-drive system  1500  incorporates a collet  1504 . To minimize the amount of actuation required collet-drive system  1500  is designed to lock half of collet  1504 , preventing rotational motion of this half, while providing a rotational degree of freedom to half of collet  1504  for unpinching and pinching of EMD  1502 . There are multiple ways to lock half of collet  1504 . The term lock refers to maintaining a component stationary and fixed relative to the patient. If the component is stationary relative to the patient bed rail then for the purposes herein the component is stationary and fixed relative to the patient. One embodiment includes engaging splines. One embodiment includes inserting a locking pin in a hole. One embodiment includes inserting a key in a keyway. One embodiment includes means for mechanical interference that prevent rotation. 
     In one embodiment, EMD  1502  is unpinched and then after EMD is unpinched, the various components are moved to a homing position to allow for removal of the EMD from the device through aligned slots. 
     Referring to  FIG. 21A  a “collet-drive system”  1600  that can rotate, translate, and pinch an EMD  1602  includes a device drive  1604 , an EMD support  1606 , and a y-connector assembly  1608 . Device drive  1604  includes a cassette  1610  and a drive module  1612 . 
     Drive module  1612  translates longitudinally relative to a fixed lead screw  1614  (identified as reference  76  in  FIG. 3 ) and is driven by an actuator  1616  (identified as translation motor  64  in  FIG. 3 .) In one embodiment lead screw  1614  is a ball screw. In one embodiment actuator  1616  is a motor powered by electrical, pneumatic, hydraulic, or other means. 
     Referring to  FIG. 21A  collet-drive system  1600  is connected to the overall robotic system  24 . In particular, the connection of lead screw  1614 , actuator  1616 , and drive module  1612  to the overall robotic system is illustrated. 
     In one embodiment translation of drive module  1612  is accomplished as described for the drive modules of  FIG. 20A . (Note that in  FIGS. 21A, 21B, 21C, and 21D  some components connecting drive module  1612  to the actuation system for translation are not shown.) 
     Referring to  FIGS. 21A, 21B, 21C, and 21D  collet drive system  1600  can pinch and unpinch EMD  1602 , rotate clockwise and rotate counterclockwise EMD  1602 , and advance and withdraw (that is, translate forward and back) EMD  1602 . In one embodiment cassette  1610  is the same as cassette  922  of  FIG. 12A  and includes a double-bevel collet and rotational drive for pinching and unpinching EMD  1602  and for rotating EMD  1602  in a pinched collet. In other words, collet drive system  1600  includes a collet such as collet  964  of  FIG. 12D  that can pinch and unpinch EMD  1602 . 
     EMD support  1606  is a constraint preventing EMD  1602  from buckling as EMD  1602  is advanced distally. In one embodiment EMD support  1606  is a system of telescoping sections with inner diameters larger than the diameter of EMD  1602 . In one embodiment EMD support  1606  is a track that allows the device to be radially loaded. In one embodiment EMD support  1606  is a tube. In one embodiment EMD support  1606  is any system that prevents EMD  1602  from buckling or bending when advancing. 
     Referring to  FIG. 21B  collet-drive system  1600  of  FIG. 21A  is indicated with a holding clamp  1618  as part of the y-connector assembly  1608 . EMD support  1606  is used between y-connector assembly  1608  and cassette  1610 . Holding clamp  1618  is a safety mechanism so EMD  1602  does not move when resetting. In one embodiment holding clamp  1618  includes two opposing blocks that can be in a clamped state that constrains the position of EMD  1602  relative to the y-connector assembly  1608  or in an unclamped state that does not constrain the position of EMD  1602  meaning that it is free to move. In one embodiment holding clamp  1618  includes two opposing pads that can be in a clamped state or in an unclamped state. The actuation system for engaging (clamping) and disengaging (unengaging) holding clamp  1618  is not shown. 
     Referring to  FIG. 21C  collet-drive system  1600  of  FIG. 21A  is indicated with a first tire  1620  and a second tire  1622  that oppose each other and press together to grip EMD  1602 . First tire  1620  and second tire  1622  are located proximal to cassette  1610 . EMD support  1606  is used between y-connector assembly  1608  and cassette  1610 . The actuation system for moving first tire  1620  and second tire  1622  toward and away from each other is not shown. Rotation of first tire  1620  and second tire  1622  at the same speed and opposing directions allows EMD  1602  to be translated at higher speed than can be accomplished using a lead screw drive. The use of first tire  1620  and second tire  1622  offers fast transverse of EMD  1602  as well as unlimited travel. In one embodiment the translational speed of device drive  1604  can be synchronized with the rotational speeds of first tire  1620  and second tire  1622  such that EMD  1602  does not move. The method to reset using the collet drive system of  21 C involves gripping EMD  1602  between tires  1620  and  1622 . Collet  964  is then unpinched freeing EMD  1602  from being fixed thereto. Drive module  1612  is then translated in a first direction while rotating tires  1620  and  1622  to maintain EMD in a fixed location relative to the earth and/or patient. Once the drive module  1612  is moved to the new desired location the collet is actuated to pinch the EMD  1602  thereto and tires  1620  and  1622  ungrip EMD  1602 . In this manner the collet drive module is reset for continued travel. In one embodiment reset occurs when translating EMD  1602  in a distal direction once drive module cannot be moved any further in the distal direction. To reset the drive module to continue driving EMD  1602  in the distal direction, drive module  1612  is moved in the proximal direction to a reset position. During translational reset for continued distal driving the first direction noted above is the proximal direction. As the drive module  1612  is moving proximal in order to maintain EMD  1602  stationary relative to the patient, tires  1620  and  1622  rotate in a manner to maintain EMD  1602  to compensate for the proximal movement of drive module  1612 . 
     Referring to  FIG. 21D  collet-drive system  1600  of  FIG. 21A  is indicated with a third tire  1624  and a fourth tire  1626  that oppose each other and press together to grip EMD  1602 . Third tire  1624  and fourth tire  1626  are located proximal to y-connector assembly  1608  and distal to EMD support  1606 . EMD support  1606  is used between y-connector assembly  1608  and cassette  1610 . Third tire  1624  and fourth tire  1626  replace the holding clamp  1618  of  FIG. 21B . The actuation system for moving third tire  1624  and fourth tire  1626  toward and away from each other is not shown. 
     COLLETS: A number of collet designs are provided herein that may be used in the robotic systems described. Referring to  FIG. 9A  a collet  800  releasably engages an EMD (not shown). Collet  800  includes an inner member  802  that is movably positioned in a distal or proximal direction within a receiving sleeve with tapered cavity  816  of outer member  804 . Outer member  804  has a longitudinal slit  805  extending from an outer surface of the outer member and terminating at its radial center. In one embodiment the walls of slit  805  are parallel. In one embodiment the walls of slit  805  are nonparallel, such as v-shaped walls with a vertex toward the radial center. In one embodiment there is a lead-in chamfer at the outer surface of slit  805 . In one embodiment there is no chamfer at the outer surface of slit  805 . 
     Referring to  FIG. 9B  inner member  802  includes a first section  806  having a generally constant radius and a second tapered section  808  that extends from first section  806  in a frusto-conical manner such that the diameter of the second section continuously decreases from a region immediately adjacent the first section to a distal free end  810  of the second section  808 , where the distal free end  810  of the second section  808  is further from the region of the second section immediately adjacent the first section  806 . In one embodiment the length of first section  806  and the length of second section  808  are the same. In one embodiment the length of first section  806  is greater than the length of second section  808 . In one embodiment the length of first section  806  is less than the length of second section  808 . 
     First section  806  has a longitudinal slit  812  extending from an outer surface of the first section and terminating at a radial center of the inner member  802 . Second tapered section  808  has a longitudinal slit  814  extending through the entire second section  808  from a portion of the outer surface of the second section in line with the slit  812  in the first section  806  to a portion of the outer surface of the second section 180 degrees from the first outer surface region. The second slit  814  defines a first plane and a second plane at an angle to the first plane. In one embodiment slit the walls of slit  812  are parallel and the walls of slit  814  are nonparallel. In one embodiment the walls of slit  812  and slit  814  are parallel. In one embodiment the walls of slit  812  and slit  814  are nonparallel. 
     Referring to  FIG. 9B  two cross-sections are indicated in  FIG. 9D  and  FIG. 9F . In one embodiment slit  812  exists in the top portion of inner member  802  and slit  812  does not exist in the bottom portion of inner member  802 . 
     Referring to  FIG. 9C  first section  806  and second section  808  are connected along a connecting portion at the lower portion of inner member  802  at seam line  807 . 
     Referring to  FIG. 9A  movement of inner member  802  from a first end  823  of outer member cavity toward the tapered end  825  of outer member cavity causes the two sections  818  and  820  to move toward one another to pinch the EMD (not shown). Similarly, movement of the inner member  802  in a direction from the second tapered end  825  of the outer member  804  toward the first open end  823  of the outer member results in the two section  818  and  820  to move away from one another pivoting about a line through the seam  807 . 
     Referring to  FIG. 9D  in one embodiment contact between inner member  802  and outer member  804  occurs between the inner circumferential surface of the tapered cavity  816  and the outer circumferential surface of the distal end  810  of the second section  808 . In one embodiment this contact is limited to 1 to 5 mm longitudinal distance. In one embodiment this contact is larger than 5 mm longitudinal distance. 
     Referring to  FIG. 9D ,  FIG. 9E , and  FIG. 9F  the two portions  818  and  820  of the second section  808  of the inner member  802  are increasingly separated in the direction of the distal end  810  in a “normally opened” unloaded configuration. 
     In operation, translational movement of the inner member  802  into the tapered cavity  816  of outer member  804  forces the two portions  818  and  820  of the second section or portion  808  to move toward each other thereby causing the two facing surfaces  819  and  821  of portions  818  and  820 , respectively, to move toward each other to pinch the EMD. As inner member  802  moves distally into outer member  804  compressive forces due to contact between inner member  802  and outer member  804  (that occur between the inner circumferential surface of the tapered cavity  816  and the outer circumferential surface of the distal end of inner second section  808 ) act on the two sections of inner member second section  808 . These forces overcome the inherent compliance of the two sections of inner member second section  808  resulting in the two facing surfaces  819  and  821  of portions  818  and  820 , respectively, moving toward one another in a loaded configuration. 
     In one embodiment in the loading configuration the inner surfaces  819  and  821  of the second section  808  of inner member  802  contact the EMD first at the distal free end  810  and then progressively continue to contact the EMD proximally in the slit  814  of inner member tapered second section  808 . 
     To move inner member  802  into outer member  804  requires an external driving force in the distal direction applied to inner member  802  from an operator or robotic system (not shown). In one embodiment the external driving force in the distal direction is applied to the proximal end of inner member  802 . In one embodiment inner member is moved relative to outer member by rotating one of the inner member  802  and outer member  804  with a rotational input that engages a screw member to translate the inner member  802  relative to outer member  804  linearly along the longitudinal axes of the collet. 
     To increasingly move inner member  802  distally into outer member  804  requires an increasing external driving force to overcome the increasing compliance force (to increasingly move the two facing surfaces  819  and  821  of portions  818  and  820 , respectively, to move toward one another) and to overcome the increasing friction force (as a result of increasing contact between the inner circumferential surface of the tapered cavity  816  and the outer circumferential surface of the distal end of second section  808 ). 
     The loaded configuration becomes a locked configuration when the two facing surfaces  819  and  821  of portions  818  and  820 , respectively, pinch down on the EMD such that the EMD cannot move. In the locked configuration no external driving force is needed. Friction forces (due to contact between the inner circumferential surface of the tapered cavity  816  and the outer circumferential surface of the distal end of second section  808 ) maintain the collet  800  in the locked configuration. In other words, in the locked configuration inner member  802  is locked with outer member  804  due to friction. 
     In operation, translational movement of the inner member  802  away from the tapered cavity  816  of outer member  804 , that is when inner member  802  is withdrawn with respect to outer member  804 , separates the two portions  818  and  820  of the second section or portion  808  from one another thereby causing the two facing surfaces  819  and  821  of portions  818  and  820 , respectively, to move away from one another to unpinch the EMD. When inner member  802  is withdrawn from outer member  804  the inherent compliance of the two sections of inner member second section  808  restores the two facing surfaces  819  and  821  of portions  818  and  820 , respectively, to their normally opened unloaded configuration. 
     To move inner member  802  away from outer member  804  requires an external driving force in the proximal direction applied to inner member  802  from an operator or robotic system (not shown). The external driving force in the proximal direction must overcome the friction force keeping the collet mechanism  800  in the locked configuration. In one embodiment the external driving force is applied to the proximal end of inner member  802 . 
     In one embodiment the two sections of inner member second section  808  are connected by a living hinge with spring properties that force the two sections away from one another as the inner member is moved toward the open end of the outer member. In one embodiment a separate spring operates to bias the two sections apart. 
     In one embodiment the outer surface of inner member tapered second section  808  has smooth walls. In one embodiment the outer surface of inner member tapered second section  808  has walls that are not smooth, for example, one or more concave pockets or wells appear on the outer surface. Designs with non-smooth walls allow for nonuniform and generally lower inherent compliance of the two sections of inner member tapered second section  808  in comparison to designs with smooth walls. 
     In one embodiment the inner member  802  is made of a moldable plastic. In one embodiment the inner surfaces  819  and  821  of the second section  808  of inner member  802  include an elastomeric or other deformable or compliant material that deforms about the EMD during pinching and in the locked configuration. 
     In one embodiment an EMD is radially loaded through outer member slit  805  and inner member slit  812  and slit  814  when slits  805 ,  812 , and  814  are aligned. The radial loading allows a user to place an EMD into the center of the collet without having to thread a free end of the EMD through a first end  823 . Rather a portion of the EMD between a first end and a second end of the EMD is placed directly into the radial center of the collet through aligned slits  805 ,  812  and  814 . In radial loading a first terminal end of the EMD remains distal the distal end of the collet and the second opposed terminal end of the EMD remains proximal the proximal end of the collet while the portion of the EMD intermediate first end and second end of the EMD is inserted through slits  805 ,  812 , and  814  to the radial center of the collet. Loading an EMD described in this paragraph is referred to herein as side loading or radial loading. 
     Referring to  FIG. 9A  and  FIG. 19D  the angle α 1   822  of the taper of the inner cavity  816  of the outer member  804  is greater than the angle α 2   824  of the taper of the outer surface of the second section  814  of the inner member thereby forcing the two portions  818  and  820  toward one another as the inner member is moved into the cavity  816  in a direction toward the second end of the outer member  804 . 
     Referring to  FIG. 9C  in one embodiment of inner member  802  the longitudinal slit  812  that extends from the outer surface of the first section  806  terminates at the central longitudinal axis of the inner member  802 . In one embodiment of inner member  802  the longitudinal slit  812  that extends from the outer surface of the first section  806  terminates off the central longitudinal axis of the inner member  802 . 
     In one embodiment first portion  818  and second portion of second section  808  defines two cantilevered portions that extend from inner member first section. Cantilevered portions  818  and  820  have a varying spring forces along their respective longitudinal length such that the surfaces  819  and  821  that contact the EMD positioned therebetween conform well to the EMD to keep pressure applied to the EMD low and spread out along the surfaces  819  and  821 . The spring force applied to the EMD can be made to vary by changing the cross-sectional thickness of the cantilevered portions  818  and  820  along the longitudinal axis of collet  800   
     Collet  800  offers the feature of increased stiffness for greater release force with full slit  814  in second section  808  of inner member  802  and partial slit  812  in first section  806  in inner member  802 . 
     Referring to  FIG. 9G  a collet  826  has an inner member  828  and an outer member  804 . Outer member  804  has the same geometry as outer member  804  described above and shown in  FIG. 9A . The principle of operation of the collet  826  is similar to that of collet  800  of  FIG. 9A . 
     Referring to  FIG. 9H  and  FIG. 9I  inner member  828  has a longitudinal slit  830  that extends from a region  832  on outer surface  834  of the inner member  828  and extends through the inner member  828  terminating in a region  836  proximate but not through the outer surface approximately 180 degrees from the opening  838  of the slit  830 . 
     Referring to  FIG. 9H  longitudinal slit  830  forms two approximately semicircular cross-sectional sections, a first section  840  and a second section  842 , of inner member  828  that pivot about a region  836  at which slit  830  terminates. In one embodiment slit  830  creates facing parallel walls from sections  840  and  842  in the unloaded configuration, that is, the unpinched state. In one embodiment slit  830  creates facing nonparallel walls, for example, such as v-shaped walls, from sections  840  and  842  in the unloaded configuration, that is, the unpinched state. In one embodiment a stress relief  848  is used at the region of the inner member proximate the bottom of the slit  830  to minimize the effects of stress concentration and thereby minimize the possibility of failure. In one embodiment other means for stress relief are employed at the region of the inner member proximate the bottom of the slit  830 . 
     Referring to  FIG. 9G  translational movement of inner member  828  from a first end  844  of outer member cavity toward the tapered end  846  of outer member cavity causes the first section  840  and second section  842  of inner member  828  to move toward one another to pinch the EMD (not shown). Similarly, translational movement of inner member  828  in a direction from the second tapered end  846  of outer member  804  toward the first open end  844  of the outer member results in the first section  840  and second section  842  of inner member  828  to move away from one another pivoting about a line through the longitudinal slit  838  to unpinch the EMD (not shown). 
     In one embodiment the region of the inner member  836  proximate the bottom of slit  830  is a living hinge with spring properties that force the two sections away from one another as the inner member is moved toward the open end of the outer member. In one embodiment a separate spring operates to bias the two sections  838  and  840  apart. 
     Friction forces (due to contact between the inner circumferential surface of the tapered cavity of outer member  804  and the outer circumferential surface of the distal end of second section  834 ) maintain the collet  826  in the locked configuration. In other words, in the locked configuration inner member  828  is locked with outer member  804  due to friction. 
     Based on the dimension and angle of longitudinal slit  830  that forms two sections, a first section  840  and a second section  842 , of inner member  828 , the collet accommodates a larger range of diameters of EMDs in comparison to the collet of  FIG F2A . 
     Referring to  FIGS. 10A and 10B  a collet  852  has an inner member  854 , two internal components including a follower pad  856  and a follower finger  858 , and an outer member  860 . Outer member  860  has a prismatic internal cavity  862  which receives internal components  856  and  858  oriented by an internal cavity  864  of inner member  854 . Outer member  860  contains a circumferential retaining channel  863  on the internal surface of the outer member toward its proximal end. Inner member  854  contains a key  859  on the outer surface of inner member that is sized to fit within channel  863 . In one embodiment follower pad  856  and follower finger  858  are separate pieces. In one embodiment follower pad  856  and follower finger  858  are integrally connected in one integrated piece. In one embodiment follower pad  856  and follower finger  858  are made of the same material. In one embodiment follower pad  856  and follower finger  858  are made of different materials. For example, in one embodiment follower pad  856  is made of an elastomeric material and follower finger  858  is made of a moldable plastic. In one embodiment follower pad  856  is made of one material. In one embodiment follower pad  856  is made of more than one material, such as a moldable plastic with an elastomeric coating. In one embodiment follower pad  856  has two parallel flat surfaces. In one embodiment follower pad  856  has two nonparallel flat surfaces. In one embodiment follower pad  856  has one flat surface and one curved surface, such as a convex surface. 
     Inner member  854  has a longitudinal slit  855  along its full length extending from an outer surface of the inner member and terminating at its radial center. Outer member  860  has a longitudinal slit  861  along its full length extending from an outer surface of the outer member and terminating at its radial center. In one embodiment slits  855  and  861  have parallel walls. In one embodiment slits  855  and  861  have nonparallel walls, such as v-shaped walls with its vertex toward the radial center. In one embodiment slits  855  and  861  have lead-in chamfers at the outer surface. In one embodiment slits  855  and  861  have no chamfers at the outer surface. 
     Referring to  FIG. 10C . 1  and  FIG. 10D . 1  diametral cross-sections of the assembled collet  852  in unpinched (open) and pinched (closed) configurations, respectively, are indicated with the configuration dependent on relative angular orientation of inner member  854  with respect to outer member  860  about a longitudinal axis. Referring to  FIG. 10C . 2  a gap  866  exists between an external surface of follower pad  856  and an internal surface of inner member  854  such that there is no pinching of EMD  867 . (EMD  867  is not shown in  FIG. 10C . 1 .) In the default unpinched configuration gap  866  exists due to dimensional geometry of an internal cam  865  of inner member  854  such that there is no contact between internal cam surface  865  and follower finger  858 . Referring to  FIG. 10D . 2  no gap  866  exists between external surface of follower pad  856  and an internal surface of inner member  854  due to the relatively larger dimension of internal cam  865  that contacts follower finger  858  such that there is pinching of EMD  867 . (EMD  867  is not shown in  FIG. 10D . 1 .) In the pinched configuration collet  852  remains in a locked state. In one embodiment the internal surface  857  of inner member  854  that receives follower pad  856  in capturing EMD  867  in the pinched configuration is flat. In one embodiment the internal surface  857  of inner member  854  that receives follower pad  856  in capturing EMD  867  in the pinched configuration is concave, for example, having a similar profile to the profile of the outer surface of follower pad  856 . In one embodiment inner member  854  is made of one material. For example, in one embodiment inner member  854  is made of moldable plastic. In one embodiment inner member  854  is made of more than one material. For example, in one embodiment the internal surface  857  of inner member  854  that receives follower pad  856  has an elastomeric lining or coating on a moldable plastic inner member  854 . 
     Transition from an unpinched to a pinched configuration or from a pinched to an unpinched configuration requires a user or a drive system to impose relative angular motion between inner member  854  and outer member  860  about the longitudinal axis. In one embodiment rotation of inner member  854  relative to outer member  860  of 90 degrees about the longitudinal axis corresponds to the transition from unpinched to pinched configurations. In one embodiment rotation of inner member  854  relative to outer member  860  of 180 degrees about the longitudinal axis corresponds to the transition from unpinched to pinched configurations. In one embodiment rotation of inner member  854  relative to outer member  860  of an arbitrary value less than 360 degrees about the longitudinal axis corresponds to the transition from unpinched to pinched configurations. 
     In one embodiment the internal cam  865  is designed to achieve pinching in a clockwise rotation of outer member  860  relative to inner member  854  about the longitudinal axis. In one embodiment the cam is designed to achieve pinching in a counterclockwise rotation of outer member  860  relative to inner member  854  about the longitudinal axis. 
     In one embodiment the internal cam  865  achieves pinching at a single position in the rotation of inner member  854  relative to outer member  860  about the longitudinal axis. In one embodiment the cam achieves pinching at two or more positions in the rotation of inner member  854  relative to outer member  860  about the longitudinal axis. 
     In one embodiment the internal cam  865  is designed with a dwell such that relative rotation between inner member  854  and outer member  860  does not result in a change of state, that is, if the collet system  852  is in a pinched configuration it remains in a pinched configuration or if the collet system  852  is in an unpinched configuration it remains in an unpinched configuration. The dwell is achieved by having no change in the radial dimension of the profile of the internal cam  865  over a range of relative rotation between inner member  854  and outer member  860 . In one embodiment in a pinched configuration a dwell accommodates for possible errors in the displacement commands to the motors rotationally driving the inner member  854  and the outer member  860  giving some tolerance to errors with the EMD  867  remaining pinched. 
     In one embodiment cam  865  is designed such that rotation of inner member  854  relative to outer member  860  of 90 degrees about the longitudinal axis maintains the EMD in the pinched configuration. In one embodiment the cam is designed such that rotation of inner member  854  relative to outer member  860  of less than 90 degrees about the longitudinal axis maintains the EMD in the pinched configuration. In one embodiment the cam is designed such that rotation of inner member  854  relative to outer member  860  of more than 90 degrees about the longitudinal axis maintains the EMD in the pinched configuration. 
     In one embodiment cam  865  is designed such that rotation of inner member  854  relative to outer member  860  of 90 degrees about the longitudinal axis maintains the EMD in the unpinched configuration. In one embodiment the cam is designed such that rotation of inner member  854  relative to outer member  860  of less than 90 degrees about the longitudinal axis maintains the EMD in the unpinched configuration. In one embodiment the cam is designed such that rotation of inner member  854  relative to outer member  860  of more than 90 degrees about the longitudinal axis maintains the EMD in the unpinched configuration. 
     In the assembled collet  852  key  859  of inner member  854  is retained in channel  863  of outer member  860  allowing for freedom of rotation of inner member  854  relative to outer member  860  and no freedom of translation of rotation of inner member  854  relative to outer member  860 . Key  859  captured in channel  863  ensures that inner member  854  and outer member  860  are aligned during assembly such that outer surface of pad  856  of follower finger  858  is positioned longitudinally opposite surface  857  in inner member  854 . Key  859  captured in channel  863  prevents both members from being pulled apart when in a pinched or unpinched configuration. 
     In an initial configuration slit  855  in inner member  854  of collet  852  is aligned with slit  861  in outer member  860  to allow for side or radial loading of EMD as described herein. 
     Referring to  FIG. 11A  a collet  868  has an inner member  870 , two internal components consisting of a flexure  872  and a collar  874 , and an outer member  876 . 
     Inner member  870  has a longitudinal slit  871  along its full length extending from an outer surface of the inner member and terminating at its radial center. Outer member  876  has a longitudinal slit  877  along its full length extending from an outer surface of the outer member and terminating at its radial center. In one embodiment slits  871  and  877  have parallel walls. In one embodiment slits  871  and  877  have nonparallel walls, such as v-shaped walls with its vertex toward the radial center. In one embodiment slits  871  and  877  have lead-in chamfers at the outer surface. In one embodiment slits  871  and  877  have no chamfers at the outer surface. 
     Referring to  FIG. 11B  collet  868  is indicated in a fully assembled configuration with slit  871  of inner member  870  and slit  877  of outer member  876  in alignment for side or radial loading of EMD  878 . 
     Referring to  FIG. 11C  inner member  870  is a single integrated member comprised of four portions with a longitudinal slit  871  from its external surface to its radial center. Starting most proximally, a first portion  882  is a cylindrical section with an internal lumen at its radial center. Distal to first portion  882  a second portion  884  is a cylindrical section with an internal cylindrical cavity. Distal to second portion  884  a third portion  886  is a cylindrical section with external threads  890  and with an internal cylindrical cavity. Distal to third portion  886  a fourth portion  888  is an extension from the third portion  886 . In one embodiment the external diameter of second portion  884  is larger than the external diameter of first portion  882 . In one embodiment the external diameter of second portion  884  is the same as the external diameter of first portion  882 . In one embodiment the external diameter of second portion  884  is smaller than the external diameter of first portion  882 . In one embodiment fourth portion  888  is a prismatic extension with a rectangular cross-section perpendicular to a longitudinal axis. In one embodiment fourth portion  888  is a prismatic extension with a non-rectangular cross-section perpendicular to a longitudinal axis. In one embodiment fourth portion  888  is a non-prismatic extension with a non-rectangular cross-section perpendicular to a longitudinal axis. 
     Outer member  876  is a single integrated member comprised of two portions with a longitudinal slit  877  from its external surface to its radial center. Starting most proximally a first portion  896  is a cylindrical cup section with internal threads  892  at its proximal portion and internal cylindrical cavity at its distal portion. Internal threads  892  mesh with external threads  890  of inner member  870 . The cylindrical cavity at the distal portion of first portion  896  receives collar  874 . A second portion  898  of outer member  876  is a cylindrical section with an internal lumen at its radial center. 
     Referring to  FIGS. 11C, 11D, and 11E  collar  874  is a cylindrical component with a distal portion that has a closed end, a proximal portion that has an internal cavity, and a keyway pocket  875  removed from its outer circumferential surface over its entire length. In one embodiment collar  874  has a closed end with a flush outer circular surface that is perpendicular to the longitudinal axis and an internal cavity. In one embodiment the closed end of collar  874  has arcuate edges to an outer circular surface that is perpendicular to the longitudinal axis with an internal cavity. In one embodiment the closed end of collar  874  has a lip or flange extending from an outer circular surface that is perpendicular to the longitudinal axis with an internal cavity. In one embodiment the internal cavity of collar  874  is centered relative to the center longitudinal axis of its outer diametral plane. In one embodiment the internal cavity of collar  874  is not centered relative to the center longitudinal axis of its outer diametral plane. In one embodiment the internal cavity of collar  874  is rectangular. In one embodiment the internal cavity of collar  874  is cylindrical. In one embodiment the internal cavity of collar  874  is not rectangular or cylindrical. In one embodiment the internal cavity of collar  874  has a corner pocket or well to receive the distal end of flexure  872 . 
     Collar  874  has a longitudinal slit  894  through the collar circumferential wall with a radial slit to its center. In one embodiment slit  894  has parallel walls. In one embodiment slit  894  has nonparallel walls, such as v-shaped walls with its vertex toward the radial center. In one embodiment slit  894  has a lead-in chamfer at the outer surface. In one embodiment slit  894  has no chamfer at the outer surface. 
     In one embodiment collar  874  is located in the distal portion of the internal cavity of outer member  876  by extension  888  of inner member  870 . Extension  888  serves as a mechanical key to ensure that collar  874  rotates with inner member  870  such that the ends of flexure  872  can be squeezed together longitudinally and not be exposed to relative rotation or torque. In other words, the ends of flexure  872  can translate relative to each other and do not rotate relative to each other. Extension  888  is constrained rotationally by a pocket  875  in collar  874  that acts a keyway and is free to translate longitudinally as inner member  870  is rotated relative to outer member  868 . 
     Referring to  FIGS. 11A and 11C  in one embodiment the proximal portion of the internal cavity of inner member  870  has a corner pocket or well to receive the proximal end of flexure  872 . Flexure  872  is a rectangular prism with a length along the axial direction that is longer than either its width or height in a plane perpendicular to the axial direction. In one embodiment flexure  872  is a rectangular prism whose width and height in a plane perpendicular to the axial direction are the same, meaning the flexure  872  has a square cross-section. In one embodiment flexure  872  is a rectangular prism whose width is larger than its height in a plane perpendicular to the axial direction, meaning the flexure  872  has a rectangular cross-section that is wider than it is higher. In one embodiment flexure  872  is a rectangular prism whose width is smaller than its height in a plane perpendicular to the axial direction, meaning the flexure  872  has a rectangular cross-section that is higher than it is wider. In one embodiment flexure  872  is a rectangular prism with sharp edges. In one embodiment flexure  872  is a rectangular prism with rounded edges. In one embodiment flexure  872  is an approximately rectangular prism. In one embodiment flexure  872  is made of a compliant material, such as a moldable plastic or acrylic. Flexure  872  has an elastic bending property that is a function of its geometry (length, width, and height) and its material properties (principally its modulus of elasticity). 
     In operation pinching EMD  878  is achieved by rotating inner member  870  relative to outer member  876  in a direction about a longitudinal axis that screws together external threads  892  and internal threads  892 . As a result, flexure  872  can be made to flex or bend (such that it has a smaller radius of curvature) and an outer surface  873  of flexure  872  (at and near the longitudinal center of the flexure) can be used to pinch EMD  878  against inner surface  880  of inner member  870 . The longitudinal distance between the two ends of flexure  872  is determined by rotation of inner member  870  relative to outer member  876  and can be used to vary the amount of flex. As the longitudinal distance between the ends of flexure  872  decreases, the flex or bend of the flexure increases giving the flexure a smaller radius of curvature and a larger lateral distance, defined as the distance perpendicular to the longitudinal axis at the longitudinal center of the flexure between the outer surface  873  of the unflexed flexure  872  and the outer surface  873  of the flexed flexure  872 . Since the lateral distance is constrained by the internal cavity, EMD  878  is trapped between outer surface  873  of flexure  872  and internal surface  880  of inner member  870 . 
     In operation unpinching EMD  878  is achieved by rotating inner member  870  relative to outer member  876  in a direction about a longitudinal axis that unscrews external threads  892  and internal threads  892 . As a result, flexure  872  can be made to unflex or unbend (such that it has a larger radius of curvature) and outer surface  873  of flexure  872  unpinches EMD  878  from inner surface  880  of inner member  870 . The longitudinal distance between the two ends of flexure  872  is determined by rotation of inner member  870  relative to outer member  876  and can be used to vary the amount of flex. As the longitudinal distance between the ends of flexure  872  increases, the flex or bend of the flexure decreases giving the flexure a larger radius of curvature and a smaller lateral distance, defined as the distance perpendicular to the longitudinal axis at the longitudinal center of the flexure between the outer surface  873  of the unflexed flexure  872  and the outer surface  873  of the flexed flexure  872 . In the unpinched configuration the lateral distance between the outer surface  873  of flexure  872  and internal surface  880  of inner member  870  is larger than the diameter of EMD  878  such that EMD  878  is free. 
     In one embodiment the internal surface  880  of inner member  870  that receives flexure  872  in capturing EMD  878  in the pinched configuration is concave, for example, having a similar profile to the profile of the outer surface  873  of flexed flexure  872 . This would increase the surface area contacting EMD  878  and can increase the resistive torque on EMD  878  by moving it away from the central axis of rotation. In one embodiment the internal surface  880  of inner member  870  that receives flexure  872  in capturing EMD  878  in the pinched configuration is flat. 
     In one embodiment inner member  870  is made of one material, for example, moldable plastic. In one embodiment inner member  870  is made of more than one material. For example, in one embodiment the internal surface  880  of inner member  870  that receives flexure  872  in capturing EMD  878  in the pinched configuration has an elastomeric lining or coating on a moldable plastic inner member  870 . 
     In one embodiment flexure  872  is made of one material, for example, moldable plastic. In one embodiment flexure  872  is made of more than one material. For example, in one embodiment flexure  872  has an elastomeric lining or coating on a moldable plastic inner portion. 
     In one embodiment of collet  868  a single flexure  872  is used. In one embodiment of collet  868  more than one flexure  872  is used. For example, two flexures oriented 180 degrees apart around the central longitudinal axis could be used to pinch and unpinch EMD  878  based on relative rotation of inner member  870  and outer member  876  using the principle described herein. 
     In an initial configuration slit  871  in inner member  870  of collet  868  is aligned with slit  877  in outer member  876  to allow for side or radial loading of EMD as described herein. 
     Referring to  FIG. 15A  a flexible bellows collet-drive system  1150  that can rotate, translate, and pinch an EMD  1154  includes a device retainer  1152 , a drive block set  1156 , and a holding block set  1158 . The device retainer  1152  is a device support that includes a longitudinal section of flexible bellows  1160  that is located between the drive block set  1156  and the holding block set  1158 . The flexible bellows  1160  is a device support that allows for translational motion between the drive block set  1156  and the holding block set  1158 . In one embodiment the drive block set  1156  is located distal to the flexible bellows  1160  and the holding block set  1158  is located proximal to the flexible bellows  1160 . In one embodiment the drive block set  1156  is located proximal to the flexible bellows  1160  and the holding block set  1158  is located distal to the flexible bellows  1160 . In one embodiment the device retainer  1152  includes a distal tapered section  1162 , a distal constant section  1164 , a proximal constant section  1166 , and a proximal tapered section  1168 . In one embodiment the device retainer  1152  includes a distal constant section  1164  and a proximal constant section  1166 , without a distal tapered section  1162  and without a proximal tapered section  1168 . 
     Referring to  FIG. 15A  the flexible bellows collet-drive system  1150  includes a translational drive system (not shown) that can translate (advance and retract) the drive block set  1156  longitudinally relative to the holding block set  1158 . 
     Referring to  FIG. 15B  the drive block set  1156  is indicated in an open configuration in which there is no contact between the drive block set  1156  and the device retainer  1152 . In one embodiment the drive block set  1156  includes a first drive block assembly  1170  and a second drive block assembly  1172 . In one embodiment the drive block set  1156  includes a first drive block assembly  1170  and no second drive block assembly  1172 . In one embodiment the design of the first block assembly  1170  and the design of the second drive block assembly  1172  are the same. In one embodiment the design of the first block assembly  1170  and the design of the second drive block assembly  1172  are not the same. 
     The first drive block assembly  1170  includes a first spur gear  1174 , a first spur gear pin  1176 , and a first drive block retainer  1178 . In one embodiment the first spur gear  1174  rotates about the first spur gear pin  1176  that is held into side walls of the first drive block retainer  1178 . In one embodiment the first spur gear  1174  is integrally connected to the first spur gear pin  1176  in the middle of its length, and the ends of the first spur gear pin  1176  on either side of the first spur gear  1174  are supported in holes that act as rotational bearings in the outer walls of the first drive block retainer  1178 . In one embodiment the first spur gear  1174  is integrally connected to the first spur gear pin  1176  in the middle of its length, and the ends of the first spur gear pin  1176  on either side of the first spur gear  1174  are supported by rotational bearings that are mounted in the outer walls of the first drive block retainer  1178 . In one embodiment the first drive block retainer  1178  includes a first drive block cutout  1180  that exposes a section of first spur gear teeth  1182  of the first spur gear  1174 . In one embodiment the first drive block cutout  1180  has a semicircular convex cross-section in a plane transverse to the longitudinal axis. 
     The second drive block assembly  1172  includes a second spur gear  1184 , a second spur gear pin  1186 , and a second drive block retainer  1188 . In one embodiment the second spur gear  1184  rotates about the second spur gear pin  1186  that is held into side walls of the second drive block retainer  1188 . In one embodiment the second spur gear  1184  is integrally connected to the second spur gear pin  1186  in the middle of its length, and the ends of the second spur gear pin  1186  on either side of the second spur gear  1184  are supported in holes that act as rotational bearings in the outer walls of the second drive block retainer  1188 . In one embodiment the second spur gear  1184  is integrally connected to the second spur gear pin  1186  in the middle of its length, and the ends of the second spur gear pin  1186  on either side of the second spur gear  1184  are supported by rotational bearings that are mounted in the outer walls of the second drive block retainer  1188 . In one embodiment the second drive block retainer  1188  includes a second drive block cutout  1190  that exposes a section of second spur gear teeth  1192  of the second spur gear  1184 . In one embodiment the second drive block cutout  1190  has a semicircular convex cross-section in a plane transverse to the longitudinal axis. 
     The first spur gear  1174  is driven by a first spur gear drive system (not shown) that can rotate the first spur gear  1174  in the clockwise direction or in the counterclockwise direction or not rotate the first spur gear  1174 . The second spur gear  1184  is driven by a second spur gear drive system (not shown) that can rotate the second spur gear  1184  in the clockwise direction or in the counterclockwise direction or not rotate the second spur gear  1184 . In one embodiment the first spur gear drive system, the second spur gear drive system, and the translational drive system are included in a combined translational-rotational drive system (not shown) that can rotate the first spur gear  1174 , rotate the second spur gear  1184 , and translate the drive block set  1156  simultaneously. In one embodiment the first spur gear drive system, the second spur gear drive system, and the translational drive system are included in a combined translational-rotational drive system (not shown) that can rotate the first spur gear  1174 , rotate the second spur gear  1184 , and translate the drive block set  1156  in sequence. 
     Referring to  FIG. 15B  the device retainer  1152  includes a geared section  1194  that is a longitudinal section with external spur gear teeth that are oriented along the longitudinal axis of the device retainer  1152  and that are sized to mesh with the teeth of the first spur gear  1174  and the teeth of the second spur gear  1184 . The geared section  1194  is located proximal to the distal constant section  1164  and distal to the flexible bellows  1160 . The length of the geared section  1194  is larger than the width of the first spur gear  1174  or the width of the second spur gear  1184 . In one embodiment the length of the geared section  1194  is ten times the width of the first spur gear  1174  or the width of the second spur gear  1184 . In one embodiment the length of the geared section  1194  is less than ten times the width of the first spur gear  1174  or the width of the second spur gear  1184 . In one embodiment the length of the geared section  1194  is more than ten times the width of the first spur gear  1174  or the width of the second spur gear  1184 . In one embodiment the spur gear teeth of the geared section  1194  are molded into the section of the device retainer  1152 . 
     In one embodiment the device retainer  1152  includes a distal drive collar  1196  and a proximal drive collar  1198 . The distal drive collar  1196  is located distal to the geared section  1194  and proximal to the distal constant section  1164 . The proximal drive collar  1198  is located proximal to the geared section  1194  and distal to the flexible bellows  1160 . The distal drive collar  1196  and the proximal drive collar  1198  are longitudinal sections with flanges or lips that extend outward from the device retainer  1152 . In one embodiment the device retainer  1152  includes a first intermediate constant section  1200  that is located distal to the flexible bellows  1160  and proximal to the proximal drive collar  1198 . 
     Referring to  FIG. 15B  and  FIG. 15D  in the open configuration of the device retainer  1152  there is an opening  1202  to a central channel  1204  for the EMD  1154 . In one embodiment the cross-section of the opening  1202  is a circular sector that is removed from a circular cross-section of the device retainer  1152  that exposes a first face  1206  and a second face  1208 . In one embodiment the cross-section of the central channel  1204  is an open circular pocket into which the EMD  1154  can be seated or held. In one embodiment the center of the central channel  1204  is aligned with the center of the device retainer  1152 . 
     Referring to  FIG. 15C  the drive block set  1156  is indicated in a closed configuration in which the first drive block assembly  1170  and the second drive block assembly  1172  move toward one another each in the direction of the central axis of the device retainer such that the exposed teeth  1182  of the first spur gear  1174  mesh with the teeth of the geared section  1194  and the exposed teeth  1192  of the second spur gear  1184  mesh with the teeth of the geared section  1194 . In the closed configuration a part of the outer distal wall of the first drive block retainer  1178  and a part of the outer distal wall of the second drive block retainer  1188  are in contact with or are close to being in contact with the distal drive collar  1196 , preventing distal motion of the first drive block assembly  1170  and of the second drive block assembly  1172  relative to the device retainer  1152 . In the closed configuration a part of the outer proximal wall of the first drive block retainer  1178  and a part of the outer proximal wall of the second drive block retainer  1188  are in contact with or are close to being in contact with the proximal drive collar  1198 , preventing proximal motion of the first drive block assembly  1170  and of the second drive block assembly  1172  relative to the device retainer  1152 . As such, in the closed configuration the drive block set  1156 , constrained by the distal drive collar  1196  and proximal drive collar  1198 , acts like a thrust bearing allowing for rotational motion of the device retainer  1152  and preventing translational of the device retainer  1152  relative to the drive block set  1156 . In other words, if there is no translational motion of the drive block set  1156  there is no translational motion of the device retainer  1152 . If there is translational motion of the drive block set  1156  (such as advancing and retracting along the longitudinal direction) there is the same corresponding translational motion of the device retainer  1152 . 
     Referring to  FIG. 15C  and  FIG. 15E  in the closed configuration of the device retainer  1152  the first face  1206  and the second face  1208  oppose each other and meet at a closed seam  1210  and the central channel  1204  encircles and pinches around the EMD  1154 . As such, in the closed configuration the EMD  1154  is pressed upon by the walls of the central cavity  1204  of the device retainer  1152  and cannot move relative to the device retainer  1152 . In other words, if there is no translational motion of the device retainer  1152  there is no translational motion of the EMD  1154 . If there is translational motion of the device retainer  1152  (such as advancing and retracting along the longitudinal direction) there is the same corresponding translational motion of the EMD  1154 . Thus, if there is no translational motion of the drive block set  1156  there is no translational motion of the EMD  1154 . If there is translational motion of the drive block set  1156  (such as advancing and retracting along the longitudinal direction) there is the same corresponding translational motion of the EMD  1154 . 
     The drive block set  1156  includes a drive block open-close actuation system (not shown) that moves the first drive block assembly  1170  and the second drive block assembly  1172  toward and away from the device retainer  1152  in a direction transverse to the longitudinal axis. Referring to  FIG. 15B  the drive block open-close actuation system has moved the first drive block assembly  1170  and the second drive block assembly  1172  to positions in the open configuration. Referring to  FIG. 15C  the drive block open-close actuation system has moved the first drive block assembly  1170  and the second drive block assembly  1172  to positions in the closed configuration. In one embodiment the drive block open-close actuation system smoothly transitions the first drive block assembly  1170  and the second drive block assembly  1172  from the open configuration to the closed configuration and from the closed configuration to the open configuration. In one embodiment the drive block open-close actuation system discretely positions the first drive block assembly  1170  and the second drive block assembly  1172  in the open configuration or the closed configuration. 
     Referring to  FIG. 15F  the holding block set  1158  is indicated in an open configuration in which there is no contact between the first holding block  1212  and the device retainer  1152  and no contact between the second holding block  1214  and the device retainer  1152 . In one embodiment the holding block set  1158  includes a first holding block  1212  and a second holding block  1214 . In one embodiment the holding block set  1158  includes a first holding block  1212  and no second holding block  1214 . In one embodiment the design of the first holding block  1212  and the design of the second holding block  1214  are the same. In one embodiment the design of the first holding block  1212  and the design of the second holding block  1214  are not the same. 
     In one embodiment the first holding block  1212  includes a first holding block cutout  1216  and the second holding block  1214  includes a second holding block cutout  1218 . In one embodiment the first holding block cutout  1216  and the second holding block  1214  each have a semicircular convex cross-section in a plane transverse to the longitudinal axis. 
     In one embodiment the device retainer  1152  includes a distal holding collar  1220  and a proximal holding collar  1222 . The distal holding collar  1220  is located proximal to the flexible bellows  1160  and distal to a constant holding section  1224 , which is a longitudinal section of the device retainer  1152  with a constant cross-section transverse to the longitudinal direction. The proximal holding collar  1222  is located distal to the proximal constant section  1166  and distal to the constant holding section  1224 . The distal holding collar  1220  and a proximal holding collar  1222  are longitudinal sections with flanges or lips that extend outward from the device retainer  1152 . In one embodiment the device retainer  1152  includes a second intermediate constant section  1226  that is located proximal to the flexible bellows  1160  and distal to the distal holding collar  1220 . Device retainer  1152  serves as anti-buckling support allowing the collet to have a longer throw than the device buckling distance. 
     Referring to  FIG. 15G  the holding block set  1158  is indicated in an intermediate configuration in which the first holding block  1212  and the second holding block  1214  move toward one another each in the direction of the central axis of the device retainer  1152 . In the intermediate configuration a part of the outer distal wall of the first holding block  1212  and a part of the outer distal wall of the second holding block  1214  are in contact with or are close to being in contact with the distal holding collar  1220 , preventing distal motion of the holding block set  1158  relative to the device retainer  1152 . In the intermediate configuration a part of the outer proximal wall of the first holding block  1212  and a part of the outer proximal wall of the second holding block  1214  are in contact with or are close to being in contact with the proximal holding collar  1222 , preventing proximal motion of the holding block set  1158  relative to the device retainer  1152 . As such, in the intermediate configuration the holding block set  1158 , constrained by the distal holding collar  1220  and a proximal holding collar  1222 , acts like a thrust bearing allowing for rotational motion of the device retainer  1152  and preventing motion translational of the device retainer  1152  relative to the holding block set  1158 . In the intermediate configuration the holding block set  1158  is constrained from translational motion and the EMD  1154  is not fully pinched. 
     Referring to  FIG. 15H  the holding block set  1158  is indicated in a closed configuration in which the first holding block  1212  and the second holding block  1214  move toward one another each in the direction of the central axis of the device retainer  1152 . In the closed configuration a part of the outer distal wall of the first holding block  1212  and a part of the outer distal wall of the second holding block  1214  are in contact with or are close to being in contact with the distal holding collar  1220 , preventing distal motion of the holding block set  1158  relative to the device retainer  1152 . In the closed configuration a part of the outer proximal wall of the first holding block  1212  and a part of the outer proximal wall of the second holding block  1214  are in contact with or are close to being in contact with the proximal holding collar  1222 , preventing proximal motion of the holding block set  1158  relative to the device retainer  1152 . As such, in the closed configuration the holding block set  1158 , constrained by distal holding collar  1220  and proximal holding collar  1222 , acts like a thrust bearing allowing for rotational motion of the device retainer  1152  and preventing motion translational of the device retainer  1152  relative to the holding block set  1158 . In the closed configuration the holding block set  1158  is constrained from translational motion and the EMD  1154  is fully pinched. 
     The holding block set  1158  includes a holding block actuation system (not shown) that moves the first holding block  1212  and the second holding block  1214  toward and away from the device retainer  1152  in a direction transverse to the longitudinal axis. Referring to  FIG. 15F  the holding block actuation system has moved the first holding block  1212  and the second holding block  1214  to positions in the open configuration. Referring to  FIG. 15G  the holding block actuation system has moved the first holding block  1212  and the second holding block  1214  to positions in an intermediate configuration. Referring to  FIG. 15H  the holding block actuation system has moved the first holding block  1212  and the second holding block  1214  to positions in the closed configuration. In one embodiment the holding block actuation system smoothly transitions the first holding block  1212  and the second holding block  1214  from the open configuration to the intermediate configuration and from the intermediate configuration to the closed configuration and from the closed configuration to the intermediate configuration and from the intermediate configuration to the open configuration. In one embodiment the holding block actuation system discretely positions the first holding block  1212  and the second holding block  1214  in the open configuration, the intermediate configuration, or the closed configuration. 
     Referring to  FIG. 16A  and  FIG. 16B  a compression collet system  1240  includes a plunger  1242 , a donut  1244 , and a receiver  1246 . In one embodiment the plunger  1242  is a rigid right circular cylinder with a central lumen  1248  with the long axis of the cylinder and with the axis of the lumen aligned with an EMD longitudinal axis  1250 . In one embodiment the lumen  1248  has a circular cross-section in a plane transverse to the EMD longitudinal axis  1250  with the lumen diameter larger than the outer diameter of an EMD  1252 . The donut  1244  is a ring torus made of a compliant material. In one embodiment the donut  1244  is an O-ring. In one embodiment the donut  1244  is made of an elastomeric material. In its rest state, that is, in an unloaded state, the donut  1244  has an internal hole  1254  with the hole diameter larger than the outer diameter of an EMD  1252 . The receiver  1246  is a rigid receptacle that includes a well  1256  and an internal lumen  1258  aligned with an EMD longitudinal axis  1250  with the lumen diameter larger than the outer diameter of an EMD  1252 . In one embodiment the receiver  1246  is a rectangular prism with a well  1256  on one face with an opening in the shape of a right circular cylinder. In one embodiment the well  1256  has straight walls. In one embodiment the well  1256  has conical walls tapered into the well. 
     Referring to  FIG. 16C  and  FIG. 16D  a plunger actuation system (not shown) translates the plunger  1242  along the EMD longitudinal axis  1250  relative to the receiver  1246  and applies a plunger force  1260 . 
     Referring to  FIG. 16C  the compression collet system  1240  is indicated in an unloaded configuration in which the plunger  1242  is not pressing against, that is, not applying a plunger force  1260  to, the donut  1244  in the well  1256 . As such, the donut  1244  is in its rest state and not deformed, and the EMD  1252  is free to translate relative to the receiver  1246 . (The donut has circular cross-sections in the poloidal plane as shown in  FIG. 16C .) 
     Referring to  FIG. 16D  the compression collet system  1240  is indicated in a loaded configuration in which the plunger  1242  is pressed against the donut  1244  in the well  1256  by a plunger force  1260 . As such, the donut  1244  is compressed and deformed (it changes its original shape, for example, from circular cross-sections to elliptical cross-sections in a poloidal plane as shown in  FIG. 16D .) In the deformed state, a portion of the deformed surface walls  1262  of the donut hole  1254  pinches around the EMD  1252 . As a result, the EMD  1252  is not free to translate relative to the receiver  1246 . 
     In one embodiment a rotational drive system (not shown) rotates (clockwise and counterclockwise) the compression collet system  1240  about the longitudinal axis  1250  of the EMD  1252 . In one embodiment a translational drive system (not shown) translates (advances and retracts) the compression collet system  1240  along the longitudinal axis  1250  of the EMD  1252 . 
     In one embodiment the compression collet system  1240  includes slits (not shown) to allow for side or radial loading of EMD  1252 . 
     In one embodiment a collet may include a collet first member and a collet second member that when moved relative to one another pinch and unpinch an EMD. In one embodiment the collet first member and the collet second member may be formed as a single component in which the collet first member and collet second member are compliantly connected. In one non-limiting example collet first member and collet second member may be connected with a living hinge, accordion portion of flexible portions that are movable relative to each other 
     Referring to  FIGS. 22A-22X  a drive mechanism  210  is a device for the actuation of tires to robotically control the movement of an EMD. In one embodiment drive mechanism has a pair of tires that pinch an EMD between them. In one embodiment, multiple pairs of tires working together including but not limited to 4 pairs in order to increase the grip on the EMD. The tires are rotated about their longitudinal axis to translate the EMD linearly along its longitudinal axis and the tires are moved axially in opposite directions to drive the EMD in rotation about its longitudinal axis. As discussed herein drive mechanism  210  includes three integrated mechanisms to rotate the tires, translate the tires axially and to pinch and unpinch the tires. Additionally, in one embodiment a clamp mechanism operates to clamp and unclamp a portion of the EMD a distance from the pair of tires. 
     Referring to  FIG. 22A  a robotic drive system includes a drive module  210  using at least one pair of tire assemblies  222  and  224  rotate EMD  208  about its longitudinal axis, translate EMD  208 . along its longitudinal axis and resets the tire assemblies during manipulation of EMD  208 . Drive module  210  is controlled by a control system. Drive module  210  includes a first actuator  240  operatively rotating a first shaft  272  and/or a second shaft  282 . A second actuator  244  operatively translating first shaft  272  along its longitudinal axis relative to the second shaft  282  between a first position and a second position. The first tire assembly  222  operatively attached to the first shaft  272  and the second tire assembly  224  is operatively attached to second shaft  282 . A third actuator  248  operatively moves first tire assembly  222  toward and away from second tire assembly  224  gripping and ungripping EMD  208  along its longitudinal axis from between first tire assembly  222  and the second tire assembly  224 . As described in more detail herein, translation of the first shaft  272  relative to the second shaft  282  rotates EMD  208  about the longitudinal axis of the EMD, and rotation of the first shaft  272  and/or second shaft  282  translates EMD  208  along the longitudinal axis of the EMD. The control system provides reset instructions to third actuator  248  to ungrip EMD  208 , second actuator  244  to move first tire assembly  222  relative to second tire assembly  224  to a reset position; and to third actuator  248  to grip EMD  208 . In one embodiment the reset instructions are provided sequentially. 
     The reset position is automatically determined as a function of one or more of input device instructions, the offset distance of the two tire assemblies and position of the EMD. 
     In one embodiment control system provides the reset instructions when the second position reaches a predetermined distance from the first position. Referring to  FIG. 22V  EMD  208  is positioned at a first position  370  and  373  on first tire assembly  222  and second tire assembly  224  respectively. In one embodiment first positions  370  and  371  are centrally positioned between a first longitudinal end  382 ,  392  and a second opposing longitudinal end  386 ,  388  of first tire assembly  222  and second tire assembly  224  respectively. In one embodiment control system provides the reset instructions when the second position reaches a predetermined distance from the first position. 
     When an operator through a user input provides instructions to rotate EMD  208  about its longitudinal axis in a first direction first tire assembly  222  and second tire assembly  224  move along their longitudinal axes in opposite directions until the EMD  208  reaches a second position  372  on first tire assembly  222  and a third position  375  of second tire assembly  224 . The controller will automatically reset first tire assembly  222  and second tire assembly  224  along their respective longitudinal axes  242 ,  246  to a reset position. If the user continues to provide instructions to rotate EMD  208  in the same first direction as or after the first tire assembly and second tire assembly reaches or reached the second and third positions respectively, the controller will automatically set the reset position to a third location  374  on the first tire assembly and a second position  372  on the second tire assembly. In this manner tire assemblies  222  and  224  are in the position to continue rotating EMD  208  in the first direction for a greater number of rotations than if the reset position was the center positions  370  and  371 . Stated another way the first tire assembly  222  and second tire assembly mover relative to one another along their respective longitudinal axes  242  and  246  between a first extended position illustrated in  FIG. 10B  and a second extended position opposite the first extended position illustrated in  FIG. 10C . In the first extended position the upper portion of first tire assembly  222  is proximate the lower portion of second tire assembly  224 . IN the second extended position the lower portion of first tire assembly  222  is proximate the upper portion of second tire assembly  224 . 
     In one embodiment the reset position is a function of the input device instructions including a duration of inactivity of the input device. Controller detects the duration of time that no instruction has been given to rotate the EMD. Once that duration reaches a predetermined time interval, the system automatically resets the first tire assembly  222  and second tire assembly  224  to an inactivity reset position. In one embodiment the inactivity reset position is a central position where the center portion of first tire assembly  222  is proximate the center portion of second tire assembly  224  such that first position  370  of the first tire assembly  222  is adjacent first position  371  of the second tire assembly  224 . However, other inactivity reset positions may be used. 
     Referring to  FIGS. 22A and 22B  the drive mechanism  210  is described in greater detail. Drive mechanism  210  includes a base  212 , actuation assembly  214  and EMD engagement mechanism  216 . Base  212  includes the components of drive mechanism  210  that are reusable. Actuation assembly  214  is operatively secured within a cavity defined by base  212 . A coupler mechanism  218  operatively connects actuation assembly  214  with the EMD engagement mechanism  216 . In one embodiment base  212  includes a top plate AA and a bottom pate BB. 
     Coupler mechanism  218  includes a first support  268  and a second support  280  that extend outwardly of base  212  via shaft  272  and shaft  282  respectively. EMD engagement mechanism  216  includes a first tire assembly  222  and a second tire assembly  224 . Tire assemblies  222  and  224  are located within a housing  220  that is operatively connected to base  212 . EMD engagement mechanism  216  includes a first tire assembly  222  and a second tire assembly  224 . In one embodiment first tire assembly  222  and second tire assembly  224  are identical. First tire assembly  222  includes a hub  226  supporting a tire  228  that is positioned about an external surface of hub  226 . Similarly, second tire assembly  224  includes a hub  227  supporting a tire  229  that is positioned about an external surface of hub  227 . Each tire  228  and  229  include a roller having a longitudinal axis about which the tire rotates. Tire  228  has an outer surface that contacts the EMD. In one embodiment the outer surface of each tire has a constant radius from a first end of the tire to the opposing second end of the tire. In one embodiment the radius of the outer surface varies along the longitudinal axis of the tire. In one embodiment the radius of the outer surface intermediate the two ends of the tire is greater than the radius of the outer center at the each of the two ends of the tire. In one embodiment the outer surface defines a prolate shape. In one embodiment the outer surface of the tires define a frusto conical shape or profile in which tires have a larger diameter proximate one free end of the tire than the other end of the tire. When the first tire and second tire grip an EMD therebetween the surfaces pressing against the EMD are substantially parallel to one another, while the surfaces of the tires that are not pressing against the EMD are not parallel. Referring to  FIG. 22P  tires having a conical shape compensate for deflections and clearances found in shafts  272 ,  282  and bearings (not shown but would be positioned in the apertures in first housing coupler  266  and second housing coupler  268 ). In the unpinched state, the conical tires would have parallel axes meaning that the surfaces would not be parallel. In the pinched state, the tire surfaces in the area of contact would be parallel. The angle of the cone is equal to the amount that the shafts are out of parallel due to shaft deflections and bearing clearances. In one embodiment the conical tires have an angle of between 0.1 and 10 degrees. In one embodiment the conical tiers have an angle of between 0.5-3.0 degrees. 
     Movement of tires  228  and  229  toward and away from each other grip and ungrip an EMD placed therebetween. As described herein movement of tires  228  and  229  about their longitudinal axis translates the EMD gripped therebetween and relative movement of tires  228  and  229  along the longitudinal axis of tires  228  and  229  rotate the gripped EMD about its longitudinal axis. 
     In one embodiment hub  226  includes a first portion  230  having an outer cylindrical shape and a second portion  232  having a frustoconical shape extending from the first portion  230  and terminating at a top end  234 . A pair of engagement arms  236  extend from a bottom of first portion  230  and terminate with a hook barb shaped member  238  that operatively engages a portion of second support  268 . 
     Referring to  FIGS. 22C and 22D  actuation assembly  214  provides three operational movements including rotational drive, axial drive, gripping/ungripping. In one embodiment clamping/unclamping drive is part of the gripping/ungripping mode or a separate fourth mode. That is the rotational drive mode rotates the EMD about its longitudinal axis. The axial drive mode drives the EMD along its longitudinal axis. The grip/ungrip and clamp/unclamp mode acts to both grip/ungrip a portion of the EMD between the two tires as well as to clamp/unclamp a portion of the EMD a distance from the two tires. In one embodiment there is no clamp. 
     A first motor  240  is operatively coupled to first tire assembly  222  providing rotational movement to first tire assembly  222  and therefore also tire  228  about a longitudinal axis  242  of first tire assembly  222 . Control of first motor  240  from the workstation provides control of the linear movement of the EMD. In one embodiment, first motor  240  has an output shaft  290  operatively coupled to a first pulley  292 . First pulley rotates with output shaft  290  and rotates a second pulley  270  via a belt  294 . In one embodiment pulley  292  and  270  are gears that are connected either directly via gear teeth or through a gear chain having at least one additional gear connecting gear  292  and  270 . In one embodiment, output shaft  290  is directly connected to shaft  272  or to tire assembly  222  with a coupler. 
     Referring to  FIG. 22F  a second motor  244  is operatively coupled to the first and second support  268 ,  280  to provide linear movement of the tire assemblies relative to one another. First tire assembly  222  moves along longitudinal axis  242  in a first direction and an opposing second direction and second tire assembly  224 . Second tire assembly includes a longitudinal axis  246  spaced from and parallel to first tire assembly longitudinal axis  242 . moves in equal distance and opposite direction along a second longitudinal axis  246  spaced from and parallel to the first longitudinal axis  242 . Control of second motor  244  from the workstation provides control of the rotational movement of the EMD. 
     Referring to  FIG. 22F  and  FIG. 22G  a third motor  248  is operatively coupled to a clamp assembly  250  that is operatively coupled to a grip/ungrip mechanism  304  effecting tire assembly  216 . As described herein control of the third motor  248  from the workstation provides resetting for the tire assemblies for discrete incremental rotation of the EMD about its longitudinal axis as well as loading and unloading the EMD. 
     Referring to  FIG. 22A  the linear drive of the actuation assembly first motor  240  in response to controls from the workstation rotates a pulley or gear  292 . A belt or gear train  294  operatively rotates a second pulley or gear operatively connected to first engagement member  218  secured to first tire assembly  216 . Rotation of an output shaft of the first motor  240  in a clockwise direction results in first tire assembly rotating in a clockwise direction about the longitudinal axis  242  of the first tire assembly  222 . Rotation of the output shaft of the first motor  240  in a counterclockwise direction results in the counterclockwise rotation of the first tire assembly  222 . In one embodiment first tire assembly  222  and second tire assembly  224  are biased toward one another such that rotation of first tire assembly  222  in the clockwise and counterclockwise orientation results in the counterclockwise and clockwise rotation respectively of the second tire assembly  224 . This motion can happen in one embodiment because the tires are in contact with each other and in one embodiment because the idler tire is being driven by the EMD. The insertion direction is defined as the direction that an EMD will move along its longitudinal axis from the proximal end of housing  220  toward the distal end of housing  220  when first tire assembly  222  is rotated counterclockwise. The insertion direction will move the EMD further into a patient&#39;s vasculature. In a withdraw direction an EMD will move along its longitudinal axis in a direction from the distal end of housing toward the proximal end of housing  220  when first tire assembly  222  is rotated clockwise. In one embodiment a longitudinal axis of the first motor output shaft is offset from the longitudinal axis  242  of the first tire assembly  222 . In one embodiment the longitudinal axis of the first motor output shaft is offset from both the longitudinal axis  242  of the first tire assembly  222  and the longitudinal axis  246  of the second tire assembly. 
     Referring to  FIGS. 22C and 22D  rotational drive includes a coupler  252  operatively connecting second motor  244  with first coupler mechanism  218  and second coupler mechanism  254 . In one embodiment second motor  244  has an output shaft that is connected to coupler  252 . Coupler  252  in one embodiment is a link being connected to the output shaft of second motor  244  at a center connector  254 . Rotation of the output shaft of second motor  244  results in rotation of coupler  252  about the axis of the output shaft of second motor  244 . A first end  256  of coupler  252  is operatively secured to the first tire assembly  222  and the second end  258  of coupler  252  is operatively secured to the second tire assembly  224 . 
     Referring to  FIG. 22D , a first end  262  of a rod  260  is pivotally secured to first end  256  of coupler  252 . A second end  264  of rod  260  is secured to a first housing coupler member  266 . Referring to  FIGS. 22M and 22N  coupler mechanism  218  include a first support or first coupler  268  having a shaft portion  272  connected to first housing coupler member  266  such that movement of first housing coupler  266  along the longitudinal axis  242  results in longitudinal movement of the first support  268  in the same direction and in equal distance as the first housing coupler. A second rod  356  includes a first end  358  pivotally secured to a second end  258  of coupler  252 . A second end  360  of second rod  356  is secured to second housing coupler  288 . First end  358  and second end  360  are secured to coupler  252  and coupler  288  with a rod end providing necessary swivel for the additional degrees of freedom required when the tire assemblies are being moved between the gripped and ungripped positions. Rotation of the output shaft of second motor  244  in a first direction results in rotation of rocker  252  in a first direction which results in movement of rod  260 , first housing coupler  266 , coupler  268  and first tire assembly in a first direction along longitudinal axis  242  and movement of second rod  356 , coupler  280  and second tire assembly  224  in a second direction along longitudinal axis  246  where the second direction is in direction parallel to and opposite the first direction. First housing coupler  266  and second housing coupler  288  move in a linear direction along longitudinal axis  242  and  246  respectively along shafts  354  and  356  respectively 
     First housing coupler  266  includes a center region housing a pulley or gear  270  secured to a shaft  272  of first support  268 . First support  268  includes a portion extending from shaft  272  away from housing coupler  266  having a first region  274  and a second frustoconical portion  276  respectively receiving portions  230  and  232  of first tire assembly  222 . First region  274  has a diameter that is greater than the diameter of shaft portion  272 . Referring to  FIG. 22N  a shelf region  278  (also referred to as a shoulder region) extends radially outward from shaft portion  272  a distance equal to the difference between the radius of the first region  274  and the radius of the shaft portion  272 . As described herein barbs  238  removably engage shelf region  278  to removably secure first tire assembly  222  from first support  268 . Shaft  272  is free to rotate within first housing coupler in response to rotation of the output shaft of first motor  240 . In one embodiment the diameters of shaft  272  and first region  274  are the same and shoulder area is defined by an inwardly extending groove in one of the shaft  272  and first region  274 . In one embodiment outwardly extending ridge may extend from the shaft or first region  274  that the tire assembly may be releasably secured to. 
     A second support or coupler  280  includes a shaft portion  282 , a conical support region  284 , a frustoconical portion  286  and a shelf region  279 . Shelf region  279  extends from shaft portion  282  a distance equal to difference between the radius of the first region  284  and the radius of the shaft portion  282 . As described herein barbs  239  removably engage shelf region  278  to removably secure second tire assembly  224  from second support  280 . Shaft  282  is free to rotate about longitudinal axis  246  within a second housing coupler  288  in response to rotation of the output shaft of first motor  240 . As discussed in further detail herein, in one embodiment installation and/or removal of first tire assembly  222  and second tire assembly  224  is accomplished via automated process controlled by the controller. 
     In one embodiment first motor  240  is operatively secured to first housing coupler  266  such that first motor  240  moves along with first housing coupler  266 . In one embodiment output shaft  290  of first motor  240  includes a key shape that engages pulley  292  such that pulley  292  moves with first housing coupler  266  while first motor  240  is fixed relative to base  212 . In one embodiment first motor  240  and pulley  292  moves in direction parallel to the longitudinal axis of shaft  272  with first housing coupler  266 . 
     Referring to  FIG. 22F  an output shaft of second motor  244  is pivotally coupled to coupler  252  at a position between the first end and the second such that clockwise rotational movement of the second motor output shaft results in a generally upward movement of the first tire assembly  222  and generally downward movement of the second tire assembly  224 . Coupler  252  is also referred to herein as a rocker as its rocks or pivots about center  254 . 
     Referring to  FIG. 22G-22J  a holding clamp  250  releasably clamps a portion of EMD  208  spaced from the first tire and the second tire along the longitudinal axis of EMD  208 . Referring to  FIG. 22G  a clamp assembly  250  includes a cam  298  operatively rotated by third motor  248 . Cam  298  has an outer circumference with an engagement portion  300  that engages a clamping pad  302  the cam  298  is rotated about a rotation axis through a certain degree of rotation (in one example through 90 degrees of rotation). A grip/ungrip mechanism  304  is operatively connected to the clamp assembly  250  to move second tire assembly  224  toward and away from first tire assembly  222  to grip and ungrip the EMD respectively therebetween. The grip/ungrip mechanism includes a link first crank  306  operatively connected to the cam  298  via a shaft  308  and coupler  310 . In one embodiment cam  298  is permanently affixed to a portion of the coupler  310 . First crank  306  is operatively connected to third motor output shaft  312 . First crank  306  is pivotally connected to a tie rod  314  having a slot  316 . A second rocker arm  318  having a follower  320  is positioned within slot  316 . Second rocker arm  318  is connected to an eccentric housing  322  that has a hole  324  off centered. Eccentric housing  322  has an outer wall with an outer diameter defining an outer surface and inner diameter defining an inner surface, wherein the outer surface and inner surface do not define concentric cylinders. Shaft  282  of second support  280  extends through hole  324  such that clockwise and counterclockwise rotation of eccentric housing  322  by movement of rocker arm  318  results in second tire assembly  224  being moved toward and away from first tire assembly  222 . An inner seal is positioned within opening  324  of eccentric housing  322  providing a seal between shaft  282  and the inner surface of eccentric housing  322  during rotation of shaft  282  within eccentric housing  322  and movement of eccentric housing upon movement of second rocker arm  318 . A second outer seal (not shown) is positioned between eccentric housing  322  and plate AA or base AA. Second outer seal allows eccentric housing  322  to be sealed relative to plate AA as the eccentric housing  322  rotates within an aperture in plate AA. 
     Referring to  FIG. 22O , in one embodiment eccentric seal assembly is between second shaft  282  and plate AA of the base housing operatively sealing the second shaft  282  from the base as the second shaft  282  is moved away from and toward the second shaft. In one embodiment eccentric housing assembly is positioned between the first shaft and the first shaft moves toward and away from the second shaft. 
     In one embodiment a drive module includes a first actuator operatively rotating a first shaft and/or a second shaft. A second actuator operatively translates the first shaft along its longitudinal axis relative to the second shaft from a first position to a second position. A first tire assembly is removably attached to the first shaft and a second tire assembly removably attached to a second shaft. An EMD having a longitudinal axis being positioned at a first location between the first tire assembly and the second tire assembly, wherein rotation of the first shaft translates an EMD along its longitudinal axis between the first tire assembly and the second tire assembly; and rotation of the second shaft rotates the EMD about its longitudinal axis. A third actuator operatively moves the first tire assembly toward and away from the second tire assembly gripping and ungripping the EMD from between the first tire assembly and the second tire assembly. A holding clamp releasably clamps a portion of the EMD spaced from the first tire and the second tire along the longitudinal axis of the EMD. In one embodiment the third actuator automatically moves the first shaft away from the second shaft and the second actuator automatically moves the first shaft back to a reset position when the first shaft reaches a predetermined distance from the first position, and the holding clamp automatically clamps the EMD while the first shaft is moved away from the second shaft. In one embodiment the third actuator operatively moves the clamp between a clamping position to an unclamped position. 
     In one embodiment drive mechanism operates in at least three different modes. In a drive mode the clamp is an unclamped position with respect to the EMD and the first tire assembly and second tire assembly grip the EMD therebetween. In a reset mode, the clamp is in a clamped position with respect to the EMD and first tire assembly being is in an ungripped position. In an exchange mode, the clamp is in the unclamped position and the tire engagement mechanism being in an the ungripped position. 
     Referring to  FIG. 22G  in a first position, clamp assembly  250  is in an unclamped position and grip/ungrip assembly  304  is in a gripped position. In this first position cam engagement portion  300  of cam  298  is spaced from the EMD and the clamping pad  302 . In this first position, the EMD is free to rotate about its longitudinal axis and move along its longitudinal axis without being impeded by the cam  298  and cam support  300 . 
     In the reset mode, prior to ungripping the EMD from between the first tire and the second tire the clamp is moved the clamped position, so the EMD is secured from movement at two locations. Stated another way a first portion of the EMD is secured from rotation and linear movement at the clamp and a second portion of the EMD is secured from rotation and linear movement between the gripped first tire and second tire. After the clamp is moved to the clamped position, the first tire and/or second tire is moved to the ungripped position. By following this sequence of first clamping and then ungripping any force or torque in the EMD does not recoil resulting in loss of positional control of the EMD such as movement of the EMD within the drive and/or proximal portion. It is desirable to maintain the existing torque in the EMD while resetting to continue rotation of the EMD. The EMD acts like a spring and failure to maintain the existing torque and/or force will result in the EMD springing back to a position once the torque and/or force is released. The reset mode allows the first tire and second tire to be repositioned to allow continued rotation of the EMD in the same direction. By way of example an EMD is initially placed located in the middle of the first tire and the middle of the second tire where the first tire and second tire are generally aligned in a neutral position. In the neutral position the center line of the first tire is in contact with the centerline of the second tire. 
     To rotate the EMD in a first direction about its longitudinal axis the first tire and second tire move in equal and opposite direction along their respective longitudinal axes. The first tire and second tire are able to continue moving in equal and opposite directions until the EMD is positioned at a terminal end of the first tire and a terminal end of the second tire. Any further movement of the tires relative to one another would result in the EMD being no longer between the first tire and second tire. To allow the tires to continue to rotate the EMD about its longitudinal axis in the first direction, the EMD is clamped and then released from between the tires and the tires move back to the neutral position. The amount of throw or distance that the wheels can move in equal and opposite directions is the distance between the neutral position and the terminal ends of the tires. When the throw falls below a predetermined amount the drive mechanism automatically resets to the neutral position or other predetermined position. In one embodiment a wire guide (Not shown) prohibits the EMD from moving from between the tires during rotation of the EMD. Wire guide also acts to trigger automatic reset of the tires if the EMD moves to the terminal edges of the tires. (Passive wire guide retains EMD between the Tire surface to maintain the EMD such a guidewire centered between the terminal ends of the tires during reset as well as to prohibit the EMD from falling off of the tires) 
     In one embodiment in the exchange mode there is no need to clamp the EMD prior to ungripping the tires to avoid recoil since the EMD will be removed from the drive mechanism. 
     Referring to  FIG. 22H  in a second position, clamp assembly  250  is in a clamped position and the grip/ungripped assembly  304  is in a gripped position. The cam engagement portion  300  is at the start of a dwell where it is clamping the EMD. The cam follower  320  of the second rocker arm  318  is now at the end of the dwell in the slot  316  of tie rod  314  such that the second tire assembly is engaged with the first tire assembly such that the EMD is gripped between the tire of the first tire assembly  222  and the tire of the second tire assembly  224 . 
     Referring to  FIG. 22I  in a third position, the clamp assembly  250  remains in a clamped position and the grip/ungrip assembly  304  is in an ungripped position such that the EMD is not gripped between the tire of the first tire assembly  222  and second tire assembly  224 . In this third position the cam engagement portion  300  is still in contact with the clamping pad  302  and is at the end of the dwell where it holds the EMD. The tire cam follower  320  rotates the eccentric which moves tire assembly  224  from tire assembly  222 . 
     Referring to  FIG. 22J  in a fourth position, clamp mechanism  250  is in an unclamped position and the grip/ungrip mechanism  304  is in an ungripped position. In this fourth position the EMD is not clamped by either the holding clamp or gripped between the first tire assembly  222  and the second tire assembly  225 . In this fourth position the engagement portion  300  is not applying a clamping force to the EMD and bushing  322  is rotated such that second tire assembly  225  is spaced from first tire assembly  222  such that there is a gap between the tires allowing the EMD to be removed from drive mechanism  210 . 
     Referring to  FIG. 22E , housing  220  is a disposable cassette that is operatively removably connected to a base  212 . In one embodiment first support coupler  268 , second support coupler  280  and cam coupler  310  are positioned above top surface  326  to respectively removably receive the first tire assembly  222 , second tire assembly  224  and cam  298 . A sterile barrier extends between housing  220  and the top surface  326  of base  212 . In one embodiment, first coupler  268 , second coupler  280  and cam coupler  310  are also included in the housing and inserted into the actuation assembly  214  via shafts  272 ,  282  and  308  respectively. 
     Referring to  FIG. 22M  first tire assembly  222  and second tire assembly  224  are removably connected to coupler  268  and coupler  280  respectively. Referring to  FIG. 22R  second tire assembly  224  is attached to coupler  280  by attachment of moving coupler  280  along linear axis  246  in a first direction  336 . The first direction is the direction along linear axis  246  in a direction away from base bottom  328  toward base top surface  326 . The second direction is the direction along linear axis  246  opposite to the first direction. As coupler  280  is moved in the first direction tire assembly  224  is restrained from moving along longitudinal axis  246  in the first direction by a restraint  332 . In one embodiment restraint  332  is a portion of a cover  334  of housing  220 . In one embodiment the restraint  332  is a separate member independent of the cover such as a shipping clip. Although not illustrated in  FIG. 22M  first tire assembly  222  and second tire assembly  224  are located within housing  220 . As top  330  of coupler  268  moves in the first direction, barbs  239  are biased in a direction away from longitudinal axis  246  until barb  239  clears the shelf region  278  of coupler  268 . Once barb  239  clears the shelf region  278 , the barbs are biased toward longitudinal axis  246 . A spring  340  biases a plunger  342  against a bottom surface  346  of the top of the second tire assembly  224 . The spring  340  maintains the second tire assembly  224  in a fixed position relative to the coupler  280 , such that rotation of coupler  280  and/or linear movement of coupler  280  results in equal rotation and/or linear movement respectively of second tire assembly  224 . In one embodiment the spring force is set with a force that is greater than the force to actuate the tires longitudinally so that the tire moves relative to the shaft with no backlash. 
     Movement of coupler  280  in the first direction is accomplished by control of second motor  244  by a controller. Attachment of first tire assembly  222  to first coupler  268  is accomplished in the same manner as attachment of second tire assembly  224  to second coupler  280 . In one embodiment a single second motor  244  controls the movement of first coupler  268  and second coupler  280  along first longitudinal axis  242  and second longitudinal axis  246  respectively, such that movement of second coupler in the first direction, results in the first coupler moving in an equal distance in a second direction. In this embodiment, the tire assemblies are attached to their respective couplers one at a time. Stated another way the tire assemblies are attached in series such that there is a time lapse between the attachment between the one tire assembly and the other tire assembly. 
     In one embodiment second motor  244  includes two separate motors independently controlling the first coupler and second coupler respectively. In the embodiment in which there are two separate motors it is possible to attach first tire assembly  222  and second tire assembly  224  to their respective couplers simultaneously. 
     Referring to  FIG. 22S-22T  removal of first tire assembly  222  and second tire assembly  224  from respective couplers  268  and  280  occurs by activating second motor  244  such that coupler  280  moves in the second direction towards top surface  326  of base  212 . A beveled portion  348  of barbs  239  of second tire assembly  224  contacts a boss  350  that biases barbs  239  in a direction away from longitudinal axis  246  until barbs  239  fully clears shelf portion  288 . Spring  340  biases the second tire assembly in a first direction that allow second tire assembly to be removed from second coupler  280 . The first tire assembly  222  is similarly removed from first coupler  268 . In one embodiment boss  350  is an integral portion of base  212  extending from top surface of base  212  and in one embodiment boss is a separate member operatively secured to base  212 . 
     Referring to  FIG. 22U  in one embodiment couplers  268  and  280  do not include a spring and plunger, rather first tire assembly  222  includes a spring member  352  operatively connected to the first tire assembly  222  such that spring  352  acts to maintain connection of the first tire assembly to the first coupler such that the first tire assembly moves along and about longitudinal axis  242  equally with movement of the first coupler. In this embodiment spring  352  is part of the disposable portion that has a single use. 
     Drive mechanism  210  includes one or more pairs of tires that grip an EMD between them. First tire  228  and second tire  229  of the pair of times are rotated to drive the EMD linearly and tires  228  and  229  are moved axially in opposite directions to drive the EMD in rotation. Drive mechanism  210  include an actuation assembly  214  that includes a number of integrated mechanisms to rotate the tires, translate the tires axially and to ungrip the tires. A rotation mechanism provides rotation of the tires by operatively coupling a first motor directly to the tire assembly directly or indirectly via a belt/gears. In one embodiment the rotation mechanism is mounted onto housing coupler  266  along a linear guide system which moves the tires and rotational motors vertically. The linear guide could include the housing coupler having a bushing riding on rods  258 . However, other linear guides known in the art may be used. To move the first housing coupler  266  and second housing coupler  288  on the linear rails or shafts  362  and  364  respectively, there are connecting rods  260  and  356  pivotally secured to a rocker  252  mounted to an output shaft of second motor  244 . To grip and ungrip the tires between tires  228  and  229  a third motor  248  operatively rotates an eccentric member  322  having an offset aperture  324  receiving one of the shafts of the first coupler and second coupler such that rotation of the bushing results in moving tires  228  and  229  away from one another. The tire assemblies  222  and  224  are located within housing  220  such as cassette that loosely holds the tire assemblies in place for assembly onto the actuation hardware supported by base  212 . The cassette  220  acts as a sterile barrier to cover the components within the base in combination with a drape. In one embodiment cassette the sterile barrier is used without a drape. The tire assemblies are fully supported by the couplers which requires a rigid connection to the tires both axially and rotationally. The rigid connection enables both rotation of the tires and vertical motion to enable rotation of the EMD. The connection between the tires and hardware is releasable to enable removal of the cassette. 
     In one embodiment, the shafts  272  and  282  and corresponding tire assemblies  222  and  224  are nominally tilted in the unloaded state by approximately 0.5-1 degree towards each other along their longitudinal axes so that the portion of the shafts proximate the shoulder region of the shafts are closer than the portion of the shafts distal the shoulder region. The amount by which the shafts are tilted corresponds to the amount of deflection of the components and the clearance in bearings and bushings so that when the tires are in the gripped state and correspondingly loaded and, the rotational axes of the tires are substantially parallel. This ensures that small diameter (as low as 0.010″) of the elongate medical devices are well-gripped by the tires and that there are no clearances due to a lack of parallelism when loaded in the gripped state. In one embodiment the longitudinal axis of the bearings in first housing coupler  362  are tilted relative to the longitudinal axis of the bearings in second housing coupler  364  or stated another way the longitudinal axis of shafts  272  are not parallel to the longitudinal axis of shafts  282 . In one embodiment the angle between the longitudinal axis of the bearings supporting shaft  272  and shaft  282  is greater than 0 degrees and less than 90 degrees. The tilt of shafts  272  and  282  are set by the location of relative angle of the longitudinal axes of bearings  362  and  364 . 
     In one embodiment robotic drive system includes a first actuator  240  operatively rotating a first shaft  272  and/or a second shaft  282  and a second actuator  244  operatively translating the first shaft  272  along its longitudinal axis relative to the second shaft  282  from a first position to a second position. A first bearing having a first longitudinal axis that supports the first shaft  272  and a second bearing having a second longitudinal axis supports the second shaft  282 ; and the first longitudinal axis and the second longitudinal axis being non-parallel. A first tire assembly  222  is removably attached to the first shaft  272  and a second tire assembly  224  is removably attached to a second shaft  282 . A third actuator  248  operatively moves the second tire assembly  224  toward and away from the first tire assembly  222  gripping and ungripping an EMD having a longitudinal axis from between the first tire assembly and the second tire assembly. In one embodiment first bearing is positioned within first housing coupler  266  and second bearing is positioned within second housing coupler  268 . However, first bearing and second bearing may be positioned elsewhere. For example, second bearing may be the eccentric bearing assembly  322 . In one embodiment the first longitudinal axis of the first bearing and the second longitudinal axis of the second bearing intersect forming an acute angle at an intersection point, wherein the first tire assembly and the second tire assembly are intermediate the intersection point and the first bearing and the second bearing. 
     In one embodiment molded in clips at the bottom of the tire assemblies clip under a lip on the coupler such as the shelf region  278 . To deal with the tolerance stack up which will necessarily involve some amount of backlash, a spring-loaded plunger is be used at the top of the coupler will ensure the clips are always in tension. For releasing the tire assemblies, the rotation mechanism can be actuated, and the clips hit a lip designed to release them and force the tire off. Once one tire assembly is off, it will float up when the other tire is released. For the initial installation, restraint  332  is a shipping clip located within housing  220  is used to hold the tires down so that both tire assemblies can be snapped in but have them still be removable by the system. 
     In one embodiment, a robotic system includes a base  212  having a first actuator  240  and a cassette  220  housing that is removably connected to the base  212 . A pair of tires  222 ,  224  are within the cassette  220 . A robotic actuator moves first shaft  272  and  282  to operatively engage first tire  222  and second tire  224  on the first shaft  272  and second shaft  282  extending from the base  212  into cassette  220 . In one embodiment the robotic actuator operatively disengages the pair of tires from the first shaft and/or second shaft. In one embodiment more than one pair of tires are positioned within cassette  220  and are operatively engaged and disengaged from respective shafts. 
     Rotation of the EMD occurs by moving tires  228  and  229  in opposite directions. Since the upward and downward movement of tires  228  and  229  is a fixed distance, in order to continue rotating the EMD in a same direction the tires need to be reset. Resetting the rotation capabilities of the tires includes incorporating a separate brake clamp that holds the EMD when tires  228  and  229  can be ungripped and then returned to the desired position after reset. The brake clamp includes a cam  298  with an engagement portion  300  and a clamp support  302 . 
     Cam  298  is rotated by a motor that is controlled by the controller. In one embodiment the motor used to rotate cam  298  is the third motor  248  that is also used to grip and ungrip the tires from one another. In one embodiment motor  248  is operatively connected to both the brake mechanism and the grip/ungrip mechanism to coordinate the timing of the brake of the EMD and the grip/ungrip of the EMD from between the tires  228  and  229 . As discussed herein first tire assembly via a first coupler  268  is mounted on an eccentric bushing  322  so that the first tire assembly can be swung away from the second tire assembly using rotation. The cam has a rocker arm that is linked to another rocker arm on the eccentric tire release by a tie rod. By linking these, as the cam is engaged with the clamp, the tires can be ungripped. 
     The drive  210  can be defined to have 3 distinct capabilities: driving, resetting, and exchanges. In the drive position, the cam is disengaged from the EMD and cam support and the follower  320  is riding free in the slot  316  so that the tires are gripped together by a spring force. In one embodiment a torsion spring (not shown) is operatively secured to the eccentric  322  and the base. In one embodiment a lever (not shown) is operatively coupled to the base with a linear spring in either compression or tension. Only rotational motion is used to grip and ungrip, accordingly, in one embodiment sealing between the base and the shafts is accomplished with a rotary shaft seal on the eccentric. 
     In the resetting position cam  298  fully clamps the EMD between the cam engagement portion  300  and the clamping pad  302  thus setting the brake before the follower  320  contacts the end of the slot  316 . A dwell on the cam allows the cam to stay fully engaged clamping the EMD as the tires  228  and  229  are ungripped enough for reset. Tires are reset by activating second motor  244  moving the first tire assembly and second tire assembly to a position to continue rotation of the EMD in the desired direction. 
     In the exchange position cam  298  is positioned such that the cam is not clamping the EMD between the engagement portion and the cam support and the first and second tires are spaced from one another in the ungripped position. In this orientation the EMD is free to be removed from the drive mechanism  210 . 
     In one embodiment a manual release is provided to release both the cam from locking the EMD and to ungrip tires  228  and  229 . The manual release overrides the controller controlling the motors in the case of a power outage or other need to quickly release the EMD from the clamp and tires. In one embodiment, a portion of the cam is operatively connected to a handle accessible to a user to manipulate such as by twisting. This design feature could be a key sufficiently large to enable a user to grip the key with the user&#39;s hand, which is easy to grip. In one embodiment only the first tire assembly moves in an up and down direction, while the second tire assembly is in a fixed up down position. In this embodiment, the mechanism described above is retained, but one of the 2 tie rods that operatively secured to rocker  252  is removed. In this mode to obtain the same amount of EMD rotation, motor  244  turn twice as much as the embodiment in which both tie rods are connected. 
     Although the present disclosure has been described with reference to example embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the defined subject matter. For example, although different example embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example embodiments or in other alternative embodiments. The present disclosure described is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the definitions reciting a single particular element also encompass a plurality of such particular elements.