Patent Publication Number: US-2022226057-A1

Title: Surgical tools with proximally mounted, cable based actuation systems

Description:
TECHNICAL FIELD 
     The systems and methods disclosed herein are directed to robotic surgical tools and, more particularly to, surgical tools with proximally mounted, cable-based actuation systems that operate distally mounted end effectors. 
     BACKGROUND 
     Minimally invasive surgical (MIS) instruments are often preferred over traditional open surgical devices due to the reduced post-operative recovery time and minimal scarring. The most common MIS procedure may be endoscopy, and the most common form of endoscopy is laparoscopy, in which one or more small incisions are formed in the abdomen of a patient and a trocar is inserted through the incision to form a pathway that provides access to the abdominal cavity. The cannula and sealing system of the trocar are used to introduce various instruments and tools into the abdominal cavity, as well as to provide insufflation to elevate the abdominal wall above the organs. The instruments can be used to engage and/or treat tissue in a number of ways to achieve a diagnostic or therapeutic effect. 
     Each surgical tool typically includes an end effector arranged at its distal end. Example end effectors include clamps, graspers, scissors, staplers, suction irrigators, blades (i.e., RF), and needle holders, and are similar to those used in conventional (open) surgery except that the end effector of each tool is separated from its handle by an approximately 12-inch long shaft. A camera or image capture device, such as an endoscope, is also commonly introduced into the abdominal cavity to enable the surgeon to view the surgical field and the operation of the end effectors during operation. The surgeon is able to view the procedure in real-time by means of a visual display in communication with the image capture device. 
     Various robotic systems have recently been developed to assist in MIS procedures. Robotic systems can allow for more intuitive hand movements by maintaining natural eye-hand axis. Robotic systems can also allow for more degrees of freedom in movement by including a “wrist” joint that creates a more natural hand-like articulation and allows for access to hard to reach spaces. The instrument&#39;s end effector can be articulated (moved) using motors and actuators forming part of a computerized motion system. A user (e.g., a surgeon) is able to remotely operate an instrument&#39;s end effector by grasping and manipulating in space one or more controllers that communicate with an instrument driver coupled to the surgical instrument. User inputs are processed by a computer system incorporated into the robotic surgical system and the instrument driver responds by actuating the motors and actuators of the motion system. Moving drive cables, rods, and/or other mechanical mechanisms causes the end effector to articulate to desired positions and configurations. 
     Improvements to robotically-enabled medical systems will provide physicians with the ability to perform endoscopic and laparoscopic procedures more effectively and with improved ease. 
     SUMMARY OF DISCLOSURE 
     Various details of the present disclosure are hereinafter summarized to provide a basic understanding. This summary is not an extensive overview of the disclosure and is neither intended to identify certain elements of the disclosure, nor to delineate the scope thereof. Rather, the primary purpose of this summary is to present some concepts of the disclosure in a simplified form prior to the more detailed description that is presented hereinafter. 
     Embodiments disclosed herein include a robotic surgical tool that includes an elongate shaft extendable through a handle providing a drive input, a drive cable extending along a portion of the shaft and having a proximal end anchored to the shaft proximal to the handle and a distal end anchored to the shaft distal to the handle, an actuation system housed within the handle and operatively coupled to the drive input such that actuation of the drive input operates the actuation system, and a toggle mechanism arranged at a proximal end of the shaft and actuatable to close or open opposing jaws of an end effector arranged at a distal end of the shaft, wherein the drive cable is threaded through portions of the actuation system and the toggle mechanism such that operation of the actuation system acts on the drive cable and thereby actuates the toggle mechanism to close or open the opposing jaws. In a further embodiment, the handle is matable with an instrument driver arranged at an end of a robotic arm, the instrument driver providing a drive output matable with the drive input, and wherein the shaft extends through the instrument driver via a central aperture defined longitudinally through the instrument driver. In another further embodiment, the actuation system comprises a drive shaft extending from the drive input, an accumulator mounted to the drive shaft such that rotation of the drive shaft correspondingly rotates the accumulator, upper and lower accumulator pulleys rotatably mounted to the drive shaft, and a side accumulator pulley laterally offset from the upper and lower accumulator pulleys, wherein the drive cable is guided through the upper and lower accumulator pulleys and the side accumulator pulley redirects the drive cable between the upper and lower accumulator pulleys. In another further embodiment, the actuation system further comprises an upper idler pulley rotatably coupled to the handle and arranged to redirect the drive cable between the shaft and the upper accumulator pulley, and a lower idler pulley rotatably coupled to the handle and arranged to redirect the drive cable between the shaft and the lower accumulator pulley. In another further embodiment, the toggle mechanism comprises a proximal link rotatably coupled to a distal link at a hinge joint, and a pusher member mounted to a movable shaft portion of the shaft and rotatably coupled to the distal link such that movement of the distal link causes the pusher member to move the movable shaft portion longitudinally along the shaft, wherein the movable shaft portion is operatively coupled to a closure tube that extends to the end effector, and wherein axial movement of the closure tube helps close or open the opposing jaws. In another further embodiment, the toggle mechanism further comprises a linkage pulley rotatably mounted to an axle at the hinge joint, and wherein the drive cable extends through the linkage pulley and operation of the actuation system applies tension on the drive cable that urges the hinge joint toward the shaft and thereby pushes the pusher member and the movable shaft portion distally. In another further embodiment, the hinge joint is spring biased away from the shaft and ceasing operation of the actuation system allows the toggle mechanism to pivot away from the shaft under spring force. In another further embodiment, at least one of the jaws is spring biased to an open position. In another further embodiment, the end effector is selected from the group consisting of a surgical stapler, a tissue grasper, surgical scissors, an advanced energy vessel sealer, a clip applier, a needle driver, a babcock including a pair of opposed grasping jaws, bipolar jaws, and any combination thereof. 
     Embodiments disclosed herein also include a method of operating a robotic surgical tool including actuating a drive input of a robotic surgical tool, the robotic surgical tool having an elongate shaft extending through a handle that provides the drive input, a drive cable extending along a portion of the shaft and having a proximal end anchored to the shaft proximal to the handle and a distal end anchored to the shaft distal to the handle, an actuation system housed within the handle and operatively coupled to the drive input, and a toggle mechanism arranged at a proximal end of the shaft, wherein the drive cable is threaded through portions of the actuation system and the toggle mechanism. The method further includes operating the actuation system by actuating the drive input and thereby drawing a portion of the drive cable into the actuation system, moving the toggle mechanism to an actuated position as the portion of the drive cable is drawn by the actuation system, the toggle mechanism being operatively coupled a closure tube extending to the end effector, and driving the closure tube distally as the toggle mechanism moves to the actuated position and thereby closing opposing jaws arranged at a distal end of the shaft. In a further embodiment, actuating the drive input of the robotic surgical tool comprises actuating a drive output mated with the drive input, wherein the handle is matable with an instrument driver arranged at an end of a robotic arm and the instrument driver provides the drive output. In another further embodiment, the method further includes releasing tension in the drive cable by ceasing operation of the actuation system, moving the toggle mechanism to an extended position as the tension in the drive cable is released, and pulling the closure tube proximally as the toggle mechanism moves to the extended position and thereby allowing the jaws to open. In another further embodiment, the hinge joint is spring biased away from the shaft and to the extended position, and wherein releasing tension in the drive cable comprises allowing a spring force of the hinge joint to pivot the bar linage mechanism to the extended position. In another further embodiment, the method further includes moving the shaft relative to the handle while simultaneously closing the jaws. In another further embodiment, wherein the actuation system comprises a drive shaft extending from the drive input, an accumulator mounted to the drive shaft, upper and lower accumulator pulleys rotatably mounted to the drive shaft, and a side accumulator pulley laterally offset from the upper and lower accumulator pulleys, the method further comprising guiding the drive cable through the upper and lower accumulator pulleys, and redirecting the drive cable between the upper and lower accumulator pulleys with the side accumulator pulley. In another further embodiment, the method further includes redirecting the drive cable between the shaft and the upper accumulator pulley with an upper idler pulley rotatably coupled to the handle, and redirecting the drive cable between the shaft and the lower accumulator pulley with a lower idler pulley rotatably coupled to the handle. In another further embodiment, the toggle mechanism includes a proximal link rotatably coupled to a distal link at a hinge joint, and a pusher member mounted to a movable shaft portion of the shaft and rotatably coupled to the distal link, and wherein moving the toggle mechanism to the actuated position further comprises moving the distal link and the pusher member distally and thereby urging the movable shaft portion distally along the shaft, moving a closure tube operatively coupled to the movable shaft portion distally, and closing the jaws with the closure tube moving distally. In another further embodiment, the toggle mechanism further includes a linkage pulley rotatably mounted to an axle at the hinge joint, the drive cable extending through the linkage pulley, and wherein operating the actuation system further comprises applying tension on the drive cable as the actuation system draws in the portion of the drive cable, and urging the hinge joint toward the shaft and to the actuated position with the drive cable acting on the linkage pulley, and thereby pushing the pusher member and the movable shaft portion distally. 
     Embodiments disclosed herein also include a robotic surgical tool that includes a shaft extended through a handle providing a drive input, an accumulator housed within the handle and operatively coupled to the drive input such that rotation of the drive input operates the accumulator, a toggle mechanism arranged at a proximal end of the shaft and operatively coupled to a closure tube extending to opposing jaws arranged at a distal end of the shaft, and a drive cable extending along the shaft and having a proximal end anchored to the shaft proximal to the handle and a distal end anchored to the shaft distal to the handle, wherein the drive cable is threaded through portions of the accumulator and the toggle mechanism, and wherein operation of the accumulator applies a tensile load on the drive cable that moves the toggle mechanism toward an actuated position, where the toggle mechanism acts on the closure tube to close the jaws. In a further embodiment, the toggle mechanism is spring biased away from the shaft and to an extended position, and wherein ceasing operation of the accumulator allows the toggle mechanism to pivot toward the extended position, which retracts the closure tube and allows the jaws to open. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements. 
         FIG. 1  illustrates an embodiment of a cart-based robotic system arranged for diagnostic and/or therapeutic bronchoscopy procedure(s). 
         FIG. 2  depicts further aspects of the robotic system of  FIG. 1 . 
         FIG. 3A  illustrates an embodiment of the robotic system of  FIG. 1  arranged for ureteroscopy. 
         FIG. 3B  illustrates an embodiment of the robotic system of  FIG. 1  arranged for a vascular procedure. 
         FIG. 4  illustrates an embodiment of a table-based robotic system arranged for a bronchoscopy procedure. 
         FIG. 5  provides an alternative view of the robotic system of  FIG. 4 . 
         FIG. 6  illustrates an example system configured to stow robotic arm(s). 
         FIG. 7A  illustrates an embodiment of a table-based robotic system configured for a ureteroscopy procedure. 
         FIG. 7B  illustrates an embodiment of a table-based robotic system configured for a laparoscopic procedure. 
         FIG. 7C  illustrates an embodiment of the table-based robotic system of  FIGS. 4-7B  with pitch or tilt adjustment. 
         FIG. 8  provides a detailed illustration of the interface between the table and the column of the table-based robotic system of  FIGS. 4-7 . 
         FIG. 9A  illustrates an alternative embodiment of a table-based robotic system. 
         FIG. 9B  illustrates an end view of the table-based robotic system of  FIG. 9A . 
         FIG. 9C  illustrates an end view of a table-based robotic system with robotic arms attached thereto. 
         FIG. 10  illustrates an exemplary instrument driver. 
         FIG. 11  illustrates an exemplary medical instrument with a paired instrument driver. 
         FIG. 12  illustrates an alternative design for an instrument driver and instrument where the axes of the drive units are parallel to the axis of the elongated shaft of the instrument. 
         FIG. 13  illustrates an instrument having an instrument-based insertion architecture. 
         FIG. 14  illustrates an exemplary controller. 
         FIG. 15  depicts a block diagram illustrating a localization system that estimates a location of one or more elements of the robotic systems of  FIGS. 1-7C , such as the location of the instrument of  FIGS. 11-13 , in accordance to an example embodiment. 
         FIG. 16  is an isometric side view of an example surgical tool that may incorporate some or all of the principles of the present disclosure. 
         FIG. 17  depicts separated isometric end views of the instrument driver and the surgical tool of  FIG. 16 . 
         FIG. 18  is an enlarged isometric view of the handle of  FIG. 16  depicting an example actuation system, according to one or more embodiments. 
         FIG. 19  is an isometric side view of the toggle mechanism of  FIG. 16 , according to one or more embodiments of the present disclosure. 
         FIG. 20  is an enlarged isometric view of the end effector and the wrist of  FIG. 16 , according to one or more embodiments. 
         FIG. 21  is an enlarged isometric view of the handle of  FIGS. 16-17  depicting another example actuation system, according to one or more embodiments. 
         FIG. 22A  is an enlarged, isometric side view of an example rocker bar system, according to one or more embodiments of the present disclosure. 
         FIG. 22B  is another enlarged, isometric side view of the rocker bar system of  FIG. 22A . 
         FIG. 23  is an enlarged isometric view of the end effector and an exposed view of the wrist of  FIGS. 16-17 , according to one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     1. Overview. 
     Aspects of the present disclosure may be integrated into a robotically-enabled medical system capable of performing a variety of medical procedures, including both minimally invasive (e.g., laparoscopy) and non-invasive (e.g., endoscopy) procedures. Among endoscopy procedures, the system may be capable of performing bronchoscopy, ureteroscopy, gastroscopy, etc. 
     In addition to performing the breadth of procedures, the system may provide additional benefits, such as enhanced imaging and guidance, to assist the physician. Additionally, the system may provide the physician with the ability to perform the procedure from an ergonomic position without the need for awkward arm motions and positions. Still further, the system may provide the physician with the ability to perform the procedure with improved ease of use such that one or more of the instruments of the system can be controlled by a single user. 
     Various embodiments will be described below in conjunction with the drawings for purposes of illustration. It should be appreciated that many other implementations of the disclosed concepts are possible, and various advantages can be achieved with the disclosed implementations. Headings are included herein for reference and to aid in locating various sections. These headings are not intended to limit the scope of the concepts described with respect thereto, as such concepts may have applicability throughout the entire specification. 
     A. Robotic System—Cart. 
     The robotically-enabled medical system may be configured in a variety of ways depending on the particular procedure.  FIG. 1  illustrates an embodiment of a cart-based robotically-enabled system  100  arranged for a diagnostic and/or therapeutic bronchoscopy procedure. For a bronchoscopy procedure, the robotic system  100  may include a cart  102  having one or more robotic arms  104  (three shown) to deliver a medical instrument (alternately referred to as a “surgical tool”), such as a steerable endoscope  106  (e.g., a procedure-specific bronchoscope for bronchoscopy), to a natural orifice access point (i.e., the mouth of the patient) to deliver diagnostic and/or therapeutic tools. As shown, the cart  102  may be positioned proximate to the patient&#39;s upper torso in order to provide access to the access point. Similarly, the robotic arms  104  may be actuated to position the bronchoscope relative to the access point. The arrangement in  FIG. 1  may also be utilized when performing a gastro-intestinal (GI) procedure with a gastroscope, a specialized endoscope for GI procedures. 
     Once the cart  102  is properly positioned adjacent the patient, the robotic arms  104  are operated to insert the steerable endoscope  106  into the patient robotically, manually, or a combination thereof. The steerable endoscope  106  may comprise at least two telescoping parts, such as an inner leader portion and an outer sheath portion, where each portion is coupled to a separate instrument driver of a set of instrument drivers  108 . As illustrated, each instrument driver  108  is coupled to the distal end of a corresponding one of the robotic arms  104 . This linear arrangement of the instrument drivers  108 , which facilitates coaxially aligning the leader portion with the sheath portion, creates a “virtual rail”  110  that may be repositioned in space by manipulating the robotic arms  104  into different angles and/or positions. Translation of the instrument drivers  108  along the virtual rail  110  telescopes the inner leader portion relative to the outer sheath portion, thus effectively advancing or retracting the endoscope  106  relative to the patient. 
     As illustrated, the virtual rail  110  (and other virtual rails described herein) is depicted in the drawings using dashed lines, thus not constituting any physical structure of the system  100 . The angle of the virtual rail  110  may be adjusted, translated, and pivoted based on clinical application or physician preference. For example, in bronchoscopy, the angle and position of the virtual rail  110  as shown represents a compromise between providing physician access to the endoscope  106  while minimizing friction that results from bending the endoscope  106  into the patient&#39;s mouth. 
     After insertion into the patient&#39;s mouth, the endoscope  106  may be directed down the patient&#39;s trachea and lungs using precise commands from the robotic system  100  until reaching a target destination or operative site. In order to enhance navigation through the patient&#39;s lung network and/or reach the desired target, the endoscope  106  may be manipulated to telescopically extend the inner leader portion from the outer sheath portion to obtain enhanced articulation and greater bend radius. The use of separate instrument drivers  108  also allows the leader portion and sheath portion to be driven independent of each other. 
     For example, the endoscope  106  may be directed to deliver a biopsy needle to a target, such as, for example, a lesion or nodule within the lungs of a patient. The needle may be deployed down a working channel that runs the length of the endoscope  106  to obtain a tissue sample to be analyzed by a pathologist. Depending on the pathology results, additional tools may be deployed down the working channel of the endoscope for additional biopsies. After identifying a tissue sample to be malignant, the endoscope  106  may endoscopically deliver tools to resect the potentially cancerous tissue. In some instances, diagnostic and therapeutic treatments can be delivered in separate procedures. In those circumstances, the endoscope  106  may also be used to deliver a fiducial marker to “mark” the location of a target nodule as well. In other instances, diagnostic and therapeutic treatments may be delivered during the same procedure. 
     The system  100  may also include a movable tower  112 , which may be connected via support cables to the cart  102  to provide support for controls, electronics, fluidics, optics, sensors, and/or power to the cart  102 . Placing such functionality in the tower  112  allows for a smaller form factor cart  102  that may be more easily adjusted and/or re-positioned by an operating physician and his/her staff. Additionally, the division of functionality between the cart/table and the support tower  112  reduces operating room clutter and facilitates improving clinical workflow. While the cart  102  may be positioned close to the patient, the tower  112  may alternatively be stowed in a remote location to stay out of the way during a procedure. 
     In support of the robotic systems described above, the tower  112  may include component(s) of a computer-based control system that stores computer program instructions, for example, within a non-transitory computer-readable storage medium such as a persistent magnetic storage drive, solid state drive, etc. The execution of those instructions, whether the execution occurs in the tower  112  or the cart  102 , may control the entire system or sub-system(s) thereof. For example, when executed by a processor of the computer system, the instructions may cause the components of the robotics system to actuate the relevant carriages and arm mounts, actuate the robotics arms, and control the medical instruments. For example, in response to receiving the control signal, motors in the joints of the robotic arms  104  may position the arms into a certain posture or angular orientation. 
     The tower  112  may also include one or more of a pump, flow meter, valve control, and/or fluid access in order to provide controlled irrigation and aspiration capabilities to the system  100  that may be deployed through the endoscope  106 . These components may also be controlled using the computer system of the tower  112 . In some embodiments, irrigation and aspiration capabilities may be delivered directly to the endoscope  106  through separate cable(s). 
     The tower  112  may include a voltage and surge protector designed to provide filtered and protected electrical power to the cart  102 , thereby avoiding placement of a power transformer and other auxiliary power components in the cart  102 , resulting in a smaller, more moveable cart  102 . 
     The tower  112  may also include support equipment for sensors deployed throughout the robotic system  100 . For example, the tower  112  may include opto-electronics equipment for detecting, receiving, and processing data received from optical sensors or cameras throughout the robotic system  100 . In combination with the control system, such opto-electronics equipment may be used to generate real-time images for display in any number of consoles deployed throughout the system, including in the tower  112 . Similarly, the tower  112  may also include an electronic subsystem for receiving and processing signals received from deployed electromagnetic (EM) sensors. The tower  112  may also be used to house and position an EM field generator for detection by EM sensors in or on the medical instrument. 
     The tower  112  may also include a console  114  in addition to other consoles available in the rest of the system, e.g., a console mounted to the cart  102 . The console  114  may include a user interface and a display screen (e.g., a touchscreen) for the physician operator. Consoles in the system  100  are generally designed to provide both robotic controls as well as pre-operative and real-time information of the procedure, such as navigational and localization information of the endoscope  106 . When the console  114  is not the only console available to the physician, it may be used by a second operator, such as a nurse, to monitor the health or vitals of the patient and the operation of system, as well as provide procedure-specific data, such as navigational and localization information. In other embodiments, the console  114  may be housed in a body separate from the tower  112 . 
     The tower  112  may be coupled to the cart  102  and endoscope  106  through one or more cables  116  connections. In some embodiments, support functionality from the tower  112  may be provided through a single cable  116  extending to the cart  102 , thus simplifying and de-cluttering the operating room. In other embodiments, specific functionality may be coupled in separate cabling and connections. For example, while power may be provided through a single power cable to the cart  102 , support for controls, optics, fluidics, and/or navigation may be provided through one or more separate cables. 
       FIG. 2  provides a detailed illustration of an embodiment of the cart  102  from the cart-based robotically-enabled system  100  of  FIG. 1 . The cart  102  generally includes an elongated support structure  202  (also referred to as a “column”), a cart base  204 , and a console  206  at the top of the column  202 . The column  202  may include one or more carriages, such as a carriage  208  (alternatively “arm support”) for supporting the deployment of the robotic arms  104 . The carriage  208  may include individually configurable arm mounts that rotate along a perpendicular axis to adjust the base  214  of the robotic arms  104  for better positioning relative to the patient. The carriage  208  also includes a carriage interface  210  that allows the carriage  208  to vertically translate along the column  202 . 
     The carriage interface  210  is connected to the column  202  through slots, such as slot  212 , that are positioned on opposite sides of the column  202  to guide the vertical translation of the carriage  208 . The slot  212  contains a vertical translation interface to position and hold the carriage  208  at various vertical heights relative to the cart base  204 . Vertical translation of the carriage  208  allows the cart  102  to adjust the reach of the robotic arms  104  to meet a variety of table heights, patient sizes, and physician preferences. Similarly, the individually configurable arm mounts on the carriage  208  allow a base  214  of the robotic arms  104  to be angled in a variety of configurations. 
     In some embodiments, the slot  212  may be supplemented with slot covers (not shown) that are flush and parallel to the slot surface to prevent dirt and fluid ingress into the internal chambers of the column  202  and the vertical translation interface as the carriage  208  vertically translates. The slot covers may be deployed through pairs of spring spools positioned near the vertical top and bottom of the slot  212 . The covers are coiled within the spools until deployed to extend and retract from their coiled state as the carriage  208  vertically translates up and down. The spring-loading of the spools provides force to retract the cover into a spool when carriage  208  translates towards the spool, while also maintaining a tight seal when the carriage  208  translates away from the spool. The covers may be connected to the carriage  208  using, for example, brackets in the carriage interface  210  to ensure proper extension and retraction of the cover as the carriage  208  translates. 
     The column  202  may internally comprise mechanisms, such as gears and motors, which are designed to use a vertically aligned lead screw to translate the carriage  208  in a mechanized fashion in response to control signals generated in response to user inputs, e.g., inputs from the console  206 . 
     The robotic arms  104  may generally comprise robotic arm bases  214  and end effectors  216  (three shown), separated by a series of linkages  218  connected by a corresponding series of joints  220 , each joint  220  including an independent actuator, and each actuator including an independently controllable motor. Each independently controllable joint  220  represents an independent degree of freedom available to the corresponding robotic arm  104 . In the illustrated embodiment, each arm  104  has seven joints  220 , thus providing seven degrees of freedom. A multitude of joints  220  result in a multitude of degrees of freedom, allowing for “redundant” degrees of freedom. Redundant degrees of freedom allow the robotic arms  104  to position their respective end effectors  216  at a specific position, orientation, and trajectory in space using different linkage positions and joint angles. This allows for the system  100  to position and direct a medical instrument from a desired point in space while allowing the physician to move the arm joints  220  into a clinically advantageous position away from the patient to create greater access, while avoiding arm collisions. 
     The cart base  204  balances the weight of the column  202 , the carriage  208 , and the arms  104  over the floor. Accordingly, the cart base  204  houses heavier components, such as electronics, motors, power supply, as well as components that either enable movement and/or immobilize the cart. For example, the cart base  204  includes rolling casters  222  that allow for the cart to easily move around the room prior to a procedure. After reaching an appropriate position, the casters  222  may be immobilized using wheel locks to hold the cart  102  in place during the procedure. 
     Positioned at the vertical end of the column  202 , the console  206  allows for both a user interface for receiving user input and a display screen (or a dual-purpose device such as, for example, a touchscreen  224 ) to provide the physician user with both pre-operative and intra-operative data. Potential pre-operative data on the touchscreen  224  may include pre-operative plans, navigation and mapping data derived from pre-operative computerized tomography (CT) scans, and/or notes from pre-operative patient interviews. Intra-operative data on the touchscreen  224  may include optical information provided from the tool, sensor and coordinate information from sensors, as well as vital patient statistics, such as respiration, heart rate, and/or pulse. The console  206  may be positioned and tilted to allow a physician to access the console from the side of the column  202  opposite carriage  208 . From this position, the physician may view the console  206 , the robotic arms  104 , and the patient while operating the console  206  from behind the cart  102 . As shown, the console  206  also includes a handle  226  to assist with maneuvering and stabilizing cart  102 . 
       FIG. 3A  illustrates an embodiment of the system  100  of  FIG. 1  arranged for ureteroscopy. In a ureteroscopic procedure, the cart  102  may be positioned to deliver a ureteroscope  302 , a procedure-specific endoscope designed to traverse a patient&#39;s urethra and ureter, to the lower abdominal area of the patient. In ureteroscopy, it may be desirable for the ureteroscope  302  to be directly aligned with the patient&#39;s urethra to reduce friction and forces on the sensitive anatomy. As shown, the cart  102  may be aligned at the foot of the table to allow the robotic arms  104  to position the ureteroscope  302  for direct linear access to the patient&#39;s urethra. From the foot of the table, the robotic arms  104  may insert the ureteroscope  302  along a virtual rail  304  directly into the patient&#39;s lower abdomen through the urethra. 
     After insertion into the urethra, using similar control techniques as in bronchoscopy, the ureteroscope  302  may be navigated into the bladder, ureters, and/or kidneys for diagnostic and/or therapeutic applications. For example, the ureteroscope  302  may be directed into the ureter and kidneys to break up kidney stone build-up using a laser or ultrasonic lithotripsy device deployed down a working channel of the ureteroscope  302 . After lithotripsy is complete, the resulting stone fragments may be removed using baskets deployed down the working channel of the ureteroscope  302 . 
       FIG. 3B  illustrates another embodiment of the system  100  of  FIG. 1  arranged for a vascular procedure. In a vascular procedure, the system  100  may be configured such that the cart  102  may deliver a medical instrument  306 , such as a steerable catheter, to an access point in the femoral artery in the patient&#39;s leg. The femoral artery presents both a larger diameter for navigation as well as a relatively less circuitous and tortuous path to the patient&#39;s heart, which simplifies navigation. As in a ureteroscopic procedure, the cart  102  may be positioned towards the patient&#39;s legs and lower abdomen to allow the robotic arms  104  to provide a virtual rail  308  with direct linear access to the femoral artery access point in the patient&#39;s thigh/hip region. After insertion into the artery, the medical instrument  306  may be directed and advanced by translating the instrument drivers  108 . Alternatively, the cart  102  may be positioned around the patient&#39;s upper abdomen in order to reach alternative vascular access points, such as, for example, the carotid and brachial arteries near the patient&#39;s shoulder and wrist. 
     B. Robotic System—Table. 
     Embodiments of the robotically-enabled medical system may also incorporate the patient&#39;s table. Incorporation of the table reduces the amount of capital equipment within the operating room by removing the cart, which allows greater access to the patient.  FIG. 4  illustrates an embodiment of such a robotically-enabled system  400  arranged for a bronchoscopy procedure. As illustrated, the system  400  includes a support structure or column  402  for supporting platform  404  (shown as a “table” or “bed”) over the floor. Much like in the cart-based systems, the end effectors of the robotic arms  406  of the system  400  comprise instrument drivers  408  that are designed to manipulate an elongated medical instrument, such as a bronchoscope  410 , through or along a virtual rail  412  formed from the linear alignment of the instrument drivers  408 . In practice, a C-arm for providing fluoroscopic imaging may be positioned over the patient&#39;s upper abdominal area by placing the emitter and detector around the table  404 . 
       FIG. 5  provides an alternative view of the system  400  without the patient and medical instrument for discussion purposes. As shown, the column  402  may include one or more carriages  502  shown as ring-shaped in the system  400 , from which the one or more robotic arms  406  may be based. The carriages  502  may translate along a vertical column interface  504  that runs the length (height) of the column  402  to provide different vantage points from which the robotic arms  406  may be positioned to reach the patient. The carriage(s)  502  may rotate around the column  402  using a mechanical motor positioned within the column  402  to allow the robotic arms  406  to have access to multiples sides of the table  404 , such as, for example, both sides of the patient. In embodiments with multiple carriages  502 , the carriages  502  may be individually positioned on the column  402  and may translate and/or rotate independent of the other carriages  502 . While carriages  502  need not surround the column  402  or even be circular, the ring-shape as shown facilitates rotation of the carriages  502  around the column  402  while maintaining structural balance. Rotation and translation of the carriages  502  allows the system  400  to align medical instruments, such as endoscopes and laparoscopes, into different access points on the patient. 
     In other embodiments (discussed in greater detail below with respect to  FIG. 9A ), the system  400  can include a patient table or bed with adjustable arm supports in the form of bars or rails extending alongside it. One or more robotic arms  406  (e.g., via a shoulder with an elbow joint) can be attached to the adjustable arm supports, which can be vertically adjusted. By providing vertical adjustment, the robotic arms  406  are advantageously capable of being stowed compactly beneath the patient table or bed, and subsequently raised during a procedure. 
     The arms  406  may be mounted on the carriages  502  through a set of arm mounts  506  comprising a series of joints that may individually rotate and/or telescopically extend to provide additional configurability to the robotic arms  406 . Additionally, the arm mounts  506  may be positioned on the carriages  502  such that when the carriages  502  are appropriately rotated, the arm mounts  506  may be positioned on either the same side of the table  404  (as shown in  FIG. 5 ), on opposite sides of table  404  (as shown in  FIG. 7B ), or on adjacent sides of the table  404  (not shown). 
     The column  402  structurally provides support for the table  404 , and a path for vertical translation of the carriages  502 . Internally, the column  402  may be equipped with lead screws for guiding vertical translation of the carriages, and motors to mechanize the translation of said carriages based the lead screws. The column  402  may also convey power and control signals to the carriage  502  and robotic arms  406  mounted thereon. 
     A table base  508  serves a similar function as the cart base  204  of the cart  102  shown in  FIG. 2 , housing heavier components to balance the table/bed  404 , the column  402 , the carriages  502 , and the robotic arms  406 . The table base  508  may also incorporate rigid casters to provide stability during procedures. Deployed from the bottom of the table base  508 , the casters may extend in opposite directions on both sides of the base  508  and retract when the system  400  needs to be moved. 
     In some embodiments, the system  400  may also include a tower (not shown) that divides the functionality of system  400  between table and tower to reduce the form factor and bulk of the table  404 . As in earlier disclosed embodiments, the tower may provide a variety of support functionalities to the table  404 , such as processing, computing, and control capabilities, power, fluidics, and/or optical and sensor processing. The tower may also be movable to be positioned away from the patient to improve physician access and de-clutter the operating room. Additionally, placing components in the tower allows for more storage space in the table base  508  for potential stowage of the robotic arms  406 . The tower may also include a master controller or console that provides both a user interface for user input, such as keyboard and/or pendant, as well as a display screen (or touchscreen) for pre-operative and intra-operative information, such as real-time imaging, navigation, and tracking information. In some embodiments, the tower may also contain holders for gas tanks to be used for insufflation. 
     In some embodiments, a table base may stow and store the robotic arms when not in use.  FIG. 6  illustrates an embodiment of the system  400  that is configured to stow robotic arms in an embodiment of the table-based system. In the system  400 , one or more carriages  602  (one shown) may be vertically translated into a base  604  to stow one or more robotic arms  606 , one or more arm mounts  608 , and the carriages  602  within the base  604 . Base covers  610  may be translated and retracted open to deploy the carriages  602 , the arm mounts  608 , and the arms  606  around the column  612 , and closed to stow and protect them when not in use. The base covers  610  may be sealed with a membrane  614  along the edges of its opening to prevent dirt and fluid ingress when closed. 
       FIG. 7A  illustrates an embodiment of the robotically-enabled table-based system  400  configured for a ureteroscopy procedure. In ureteroscopy, the table  404  may include a swivel portion  702  for positioning a patient off-angle from the column  402  and the table base  508 . The swivel portion  702  may rotate or pivot around a pivot point (e.g., located below the patient&#39;s head) in order to position the bottom portion of the swivel portion  702  away from the column  402 . For example, the pivoting of the swivel portion  702  allows a C-arm (not shown) to be positioned over the patient&#39;s lower abdomen without competing for space with the column (not shown) below table  404 . By rotating the carriage (not shown) around the column  402 , the robotic arms  406  may directly insert a ureteroscope  704  along a virtual rail  706  into the patient&#39;s groin area to reach the urethra. In ureteroscopy, stirrups  708  may also be fixed to the swivel portion  702  of the table  404  to support the position of the patient&#39;s legs during the procedure and allow clear access to the patient&#39;s groin area. 
       FIG. 7B  illustrates an embodiment of the system  400  configured for a laparoscopic procedure. In a laparoscopic procedure, through small incision(s) in the patient&#39;s abdominal wall, minimally invasive instruments may be inserted into the patient&#39;s anatomy. In some embodiments, the minimally invasive instruments comprise an elongated rigid member, such as a shaft, which is used to access anatomy within the patient. After inflation of the patient&#39;s abdominal cavity, the instruments may be directed to perform surgical or medical tasks, such as grasping, cutting, ablating, suturing, etc. In some embodiments, the instruments can comprise a scope, such as a laparoscope. As shown in  FIG. 7B , the carriages  502  of the system  400  may be rotated and vertically adjusted to position pairs of the robotic arms  406  on opposite sides of the table  404 , such that an instrument  710  may be positioned using the arm mounts  506  to be passed through minimal incisions on both sides of the patient to reach his/her abdominal cavity. 
     To accommodate laparoscopic procedures, the system  400  may also tilt the platform to a desired angle.  FIG. 7C  illustrates an embodiment of the system  400  with pitch or tilt adjustment. As shown in  FIG. 7C , the system  400  may accommodate tilt of the table  404  to position one portion of the table  404  at a greater distance from the floor than the other. Additionally, the arm mounts  506  may rotate to match the tilt such that the arms  406  maintain the same planar relationship with table  404 . To accommodate steeper angles, the column  402  may also include telescoping portions  712  that allow vertical extension of the column  402  to keep the table  404  from touching the floor or colliding with the base  508 . 
       FIG. 8  provides a detailed illustration of the interface between the table  404  and the column  402 . Pitch rotation mechanism  802  may be configured to alter the pitch angle of the table  404  relative to the column  402  in multiple degrees of freedom. The pitch rotation mechanism  802  may be enabled by the positioning of orthogonal axes A and B at the column-table interface, each axis actuated by a separate motor  804   a  and  804   b  responsive to an electrical pitch angle command. Rotation along one screw  806   a  would enable tilt adjustments in one axis A, while rotation along another screw  806   b  would enable tilt adjustments along the other axis B. In some embodiments, a ball joint can be used to alter the pitch angle of the table  404  relative to the column  402  in multiple degrees of freedom. 
     For example, pitch adjustments are particularly useful when trying to position the table in a Trendelenburg position, i.e., position the patient&#39;s lower abdomen at a higher position from the floor than the patient&#39;s lower abdomen, for lower abdominal surgery. The Trendelenburg position causes the patient&#39;s internal organs to slide towards his/her upper abdomen through the force of gravity, clearing out the abdominal cavity for minimally invasive tools to enter and perform lower abdominal surgical or medical procedures, such as laparoscopic prostatectomy. 
       FIGS. 9A and 9B  illustrate isometric and end views, respectively, of an alternative embodiment of a table-based surgical robotics system  900 . The surgical robotics system  900  includes one or more adjustable arm supports  902  that can be configured to support one or more robotic arms (see, for example,  FIG. 9C ) relative to a table  904 . In the illustrated embodiment, a single adjustable arm support  902  is shown, though an additional arm support can be provided on an opposite side of the table  904 . The adjustable arm support  902  can be configured so that it can move relative to the table  904  to adjust and/or vary the position of the adjustable arm support  902  and/or any robotic arms mounted thereto relative to the table  904 . For example, the adjustable arm support  902  may be adjusted in one or more degrees of freedom relative to the table  904 . The adjustable arm support  902  provides high versatility to the system  900 , including the ability to easily stow the one or more adjustable arm supports  902  and any robotics arms attached thereto beneath the table  904 . The adjustable arm support  902  can be elevated from the stowed position to a position below an upper surface of the table  904 . In other embodiments, the adjustable arm support  902  can be elevated from the stowed position to a position above an upper surface of the table  904 . 
     The adjustable arm support  902  can provide several degrees of freedom, including lift, lateral translation, tilt, etc. In the illustrated embodiment of  FIGS. 9A and 9B , the arm support  902  is configured with four degrees of freedom, which are illustrated with arrows in  FIG. 9A . A first degree of freedom allows for adjustment of the adjustable arm support  902  in the z-direction (“Z-lift”). For example, the adjustable arm support  902  can include a carriage  906  configured to move up or down along or relative to a column  908  supporting the table  904 . A second degree of freedom can allow the adjustable arm support  902  to tilt. For example, the adjustable arm support  902  can include a rotary joint, which can allow the adjustable arm support  902  to be aligned with the bed in a Trendelenburg position. A third degree of freedom can allow the adjustable arm support  902  to “pivot up,” which can be used to adjust a distance between a side of the table  904  and the adjustable arm support  902 . A fourth degree of freedom can permit translation of the adjustable arm support  902  along a longitudinal length of the table. 
     The surgical robotics system  900  in  FIGS. 9A and 9B  can comprise a table  904  supported by a column  908  that is mounted to a base  910 . The base  910  and the column  908  support the table  904  relative to a support surface. A floor axis  912  and a support axis  914  are shown in  FIG. 9B . 
     The adjustable arm support  902  can be mounted to the column  908 . In other embodiments, the arm support  902  can be mounted to the table  904  or the base  910 . The adjustable arm support  902  can include a carriage  906 , a bar or rail connector  916  and a bar or rail  918 . In some embodiments, one or more robotic arms mounted to the rail  918  can translate and move relative to one another. 
     The carriage  906  can be attached to the column  908  by a first joint  920 , which allows the carriage  906  to move relative to the column  908  (e.g., such as up and down a first or vertical axis  922 ). The first joint  920  can provide the first degree of freedom (“Z-lift”) to the adjustable arm support  902 . The adjustable arm support  902  can include a second joint  924 , which provides the second degree of freedom (tilt) for the adjustable arm support  902 . The adjustable arm support  902  can include a third joint  926 , which can provide the third degree of freedom (“pivot up”) for the adjustable arm support  902 . An additional joint  928  (shown in  FIG. 9B ) can be provided that mechanically constrains the third joint  926  to maintain an orientation of the rail  918  as the rail connector  916  is rotated about a third axis  930 . The adjustable arm support  902  can include a fourth joint  932 , which can provide a fourth degree of freedom (translation) for the adjustable arm support  902  along a fourth axis  934 . 
       FIG. 9C  illustrates an end view of the surgical robotics system  900  with two adjustable arm supports  902   a  and  902   b  mounted on opposite sides of the table  904 . A first robotic arm  936   a  is attached to the first bar or rail  918   a  of the first adjustable arm support  902   a.  The first robotic arm  936   a  includes a base  938   a  attached to the first rail  918   a.  The distal end of the first robotic arm  936   a  includes an instrument drive mechanism or input  940   a  that can attach to one or more robotic medical instruments or tools. Similarly, the second robotic arm  936   b  includes a base  938   a  attached to the second rail  918   b.  The distal end of the second robotic arm  936   b  includes an instrument drive mechanism or input  940   b  configured to attach to one or more robotic medical instruments or tools. 
     In some embodiments, one or more of the robotic arms  936   a,b  comprises an arm with seven or more degrees of freedom. In some embodiments, one or more of the robotic arms  936   a,b  can include eight degrees of freedom, including an insertion axis (1-degree of freedom including insertion), a wrist (3-degrees of freedom including wrist pitch, yaw and roll), an elbow (1-degree of freedom including elbow pitch), a shoulder (2-degrees of freedom including shoulder pitch and yaw), and base  938   a,b  (1-degree of freedom including translation). In some embodiments, the insertion degree of freedom can be provided by the robotic arm  936   a,b,  while in other embodiments, the instrument itself provides insertion via an instrument-based insertion architecture. 
     C. Instrument Driver &amp; Interface. 
     The end effectors of a system&#39;s robotic arms comprise (i) an instrument driver (alternatively referred to as “tool driver,” “instrument drive mechanism,” “instrument device manipulator,” and “drive input”) that incorporate electro-mechanical means for actuating the medical instrument, and (ii) a removable or detachable medical instrument, which may be devoid of any electro-mechanical components, such as motors. This dichotomy may be driven by the need to sterilize medical instruments used in medical procedures, and the inability to adequately sterilize expensive capital equipment due to their intricate mechanical assemblies and sensitive electronics. Accordingly, the medical instruments may be designed to be detached, removed, and interchanged from the instrument driver (and thus the system) for individual sterilization or disposal by the physician or the physician&#39;s staff. In contrast, the instrument drivers need not be changed or sterilized, and may be draped for protection. 
       FIG. 10  illustrates an example instrument driver  1000 , according to one or more embodiments. Positioned at the distal end of a robotic arm, the instrument driver  1000  includes one or more drive outputs  1002  arranged with parallel axes to provide controlled torque to a medical instrument via corresponding drive shafts  1004 . Each drive output  1002  comprises an individual drive shaft  1004  for interacting with the instrument, a gear head  1006  for converting the motor shaft rotation to a desired torque, a motor  1008  for generating the drive torque, and an encoder  1010  to measure the speed of the motor shaft and provide feedback to control circuitry  1012 , which can also be used for receiving control signals and actuating the drive output  1002 . Each drive output  1002  being independently controlled and motorized, the instrument driver  1000  may provide multiple (at least two shown in  FIG. 10 ) independent drive outputs to the medical instrument. In operation, the control circuitry  1012  receives a control signal, transmits a motor signal to the motor  1008 , compares the resulting motor speed as measured by the encoder  1010  with the desired speed, and modulates the motor signal to generate the desired torque. 
     For procedures that require a sterile environment, the robotic system may incorporate a drive interface, such as a sterile adapter connected to a sterile drape that sits between the instrument driver and the medical instrument. The chief purpose of the sterile adapter is to transfer angular motion from the drive shafts of the instrument driver to the drive inputs of the instrument while maintaining physical separation, and thus sterility, between the drive shafts and drive inputs. Accordingly, an example sterile adapter may comprise a series of rotational inputs and outputs intended to be mated with the drive shafts of the instrument driver and drive inputs on the instrument. Connected to the sterile adapter, the sterile drape, comprised of a thin, flexible material such as transparent or translucent plastic, is designed to cover the capital equipment, such as the instrument driver, robotic arm, and cart (in a cart-based system) or table (in a table-based system). Use of the drape would allow the capital equipment to be positioned proximate to the patient while still being located in an area not requiring sterilization (i.e., non-sterile field). On the other side of the sterile drape, the medical instrument may interface with the patient in an area requiring sterilization (i.e., sterile field). 
     D. Medical Instrument. 
       FIG. 11  illustrates an example medical instrument  1100  with a paired instrument driver  1102 . Like other instruments designed for use with a robotic system, the medical instrument  1100  (alternately referred to as a “surgical tool”) comprises an elongated shaft  1104  (or elongate body) and an instrument base  1106 . The instrument base  1106 , also referred to as an “instrument handle” due to its intended design for manual interaction by the physician, may generally comprise rotatable drive inputs  1108 , e.g., receptacles, pulleys or spools, that are designed to be mated with drive outputs  1110  that extend through a drive interface on the instrument driver  1102  at the distal end of a robotic arm  1112 . When physically connected, latched, and/or coupled, the mated drive inputs  1108  of the instrument base  1106  may share axes of rotation with the drive outputs  1110  in the instrument driver  1102  to allow the transfer of torque from the drive outputs  1110  to the drive inputs  1108 . In some embodiments, the drive outputs  1110  may comprise splines that are designed to mate with receptacles on the drive inputs  1108 . 
     The elongated shaft  1104  is designed to be delivered through either an anatomical opening or lumen, e.g., as in endoscopy, or a minimally invasive incision, e.g., as in laparoscopy. The elongated shaft  1104  may be either flexible (e.g., having properties similar to an endoscope) or rigid (e.g., having properties similar to a laparoscope) or contain a customized combination of both flexible and rigid portions. When designed for laparoscopy, the distal end of the shaft  1104  may be connected to an end effector extending from a jointed wrist formed from a clevis with at least one degree of freedom and a surgical tool or medical instrument, such as, for example, a grasper or scissors, that may be actuated based on force from the tendons as the drive inputs  1008  rotate in response to torque received from the drive outputs  1110  of the instrument driver  1102 . When designed for endoscopy, the distal end of the flexible elongated shaft  1104  may include a steerable or controllable bending section that may be articulated and bent based on torque received from the drive outputs  1110  of the instrument driver  1102 . 
     In some embodiments, torque from the instrument driver  1102  is transmitted down the elongated shaft  1104  using tendons along the shaft  1104 . These individual tendons, such as pull wires, may be individually anchored to individual drive inputs  1108  within the instrument handle  1106 . From the handle  1106 , the tendons are directed down one or more pull lumens along the elongated shaft  1104  and anchored at the distal portion of the elongated shaft  1104 , or in the wrist at the distal portion of the elongated shaft. During a surgical procedure, such as a laparoscopic, endoscopic, or a hybrid procedure, these tendons may be coupled to a distally mounted end effector, such as a wrist, a grasper, or scissors. Under such an arrangement, torque exerted on the drive inputs  1108  would transfer tension to the tendon, thereby causing the end effector to actuate in some way. In some embodiments, during a surgical procedure, the tendon may cause a joint to rotate about an axis, thereby causing the end effector to move in one direction or another. Alternatively, the tendon may be connected to one or more jaws of a grasper at distal end of the elongated shaft  1104 , where tension from the tendon cause the grasper to close. 
     In endoscopy, the tendons may be coupled to a bending or articulating section positioned along the elongated shaft  1104  (e.g., at the distal end) via adhesive, control ring, or other mechanical fixation. When fixedly attached to the distal end of a bending section, torque exerted on drive inputs  1108  would be transmitted down the tendons, causing the softer, bending section (sometimes referred to as the articulable section or region) to bend or articulate. Along the non-bending sections, it may be advantageous to spiral or helix the individual pull lumens that direct the individual tendons along (or inside) the walls of the endoscope shaft to balance the radial forces that result from tension in the pull wires. The angle of the spiraling and/or spacing there between may be altered or engineered for specific purposes, wherein tighter spiraling exhibits lesser shaft compression under load forces, while lower amounts of spiraling results in greater shaft compression under load forces, but also exhibits limits bending. On the other end of the spectrum, the pull lumens may be directed parallel to the longitudinal axis of the elongated shaft  1104  to allow for controlled articulation in the desired bending or articulable sections. 
     In endoscopy, the elongated shaft  1104  houses a number of components to assist with the robotic procedure. The shaft may comprise a working channel for deploying surgical tools (or medical instruments), irrigation, and/or aspiration to the operative region at the distal end of the shaft  1104 . The shaft  1104  may also accommodate wires and/or optical fibers to transfer signals to/from an optical assembly at the distal tip, which may include of an optical camera. The shaft  1104  may also accommodate optical fibers to carry light from proximally-located light sources, such as light emitting diodes, to the distal end of the shaft. 
     At the distal end of the instrument  1100 , the distal tip may also comprise the opening of a working channel for delivering tools for diagnostic and/or therapy, irrigation, and aspiration to an operative site. The distal tip may also include a port for a camera, such as a fiberscope or a digital camera, to capture images of an internal anatomical space. Relatedly, the distal tip may also include ports for light sources for illuminating the anatomical space when using the camera. 
     In the example of  FIG. 11 , the drive shaft axes, and thus the drive input axes, are orthogonal to the axis of the elongated shaft. This arrangement, however, complicates roll capabilities for the elongated shaft  1104 . Rolling the elongated shaft  1104  along its axis while keeping the drive inputs  1108  static results in undesirable tangling of the tendons as they extend off the drive inputs  1108  and enter pull lumens within the elongated shaft  1104 . The resulting entanglement of such tendons may disrupt any control algorithms intended to predict movement of the flexible elongated shaft during an endoscopic procedure. 
       FIG. 12  illustrates an alternative design for a circular instrument driver  1200  and corresponding instrument  1202  (alternately referred to as a “surgical tool”) where the axes of the drive units are parallel to the axis of the elongated shaft  1206  of the instrument  1202 . As shown, the instrument driver  1200  comprises four drive units with corresponding drive outputs  1208  aligned in parallel at the end of a robotic arm  1210 . The drive units and their respective drive outputs  1208  are housed in a rotational assembly  1212  of the instrument driver  1200  that is driven by one of the drive units within the assembly  1212 . In response to torque provided by the rotational drive unit, the rotational assembly  1212  rotates along a circular bearing that connects the rotational assembly  1212  to a non-rotational portion  1214  of the instrument driver  1200 . Power and control signals may be communicated from the non-rotational portion  1214  of the instrument driver  1200  to the rotational assembly  1212  through electrical contacts maintained through rotation by a brushed slip ring connection (not shown). In other embodiments, the rotational assembly  1212  may be responsive to a separate drive unit that is integrated into the non-rotatable portion  1214 , and thus not in parallel with the other drive units. The rotational assembly  1212  allows the instrument driver  1200  to rotate the drive units and their respective drive outputs  1208  as a single unit around an instrument driver axis  1216 . 
     Like earlier disclosed embodiments, the instrument  1202  may include an elongated shaft  1206  and an instrument base  1218  (shown in phantom) including a plurality of drive inputs  1220  (such as receptacles, pulleys, and spools) that are configured to mate with the drive outputs  1208  of the instrument driver  1200 . Unlike prior disclosed embodiments, the instrument shaft  1206  extends from the center of the instrument base  1218  with an axis substantially parallel to the axes of the drive inputs  1220 , rather than orthogonal as in the design of  FIG. 11 . 
     When coupled to the rotational assembly  1212  of the instrument driver  1200 , the medical instrument  1202 , comprising instrument base  1218  and instrument shaft  1206 , rotates in combination with the rotational assembly  1212  about the instrument driver axis  1216 . Since the instrument shaft  1206  is positioned at the center of the instrument base  1218 , the instrument shaft  1206  is coaxial with the instrument driver axis  1216  when attached. Thus, rotation of the rotational assembly  1212  causes the instrument shaft  1206  to rotate about its own longitudinal axis. Moreover, as the instrument base  1218  rotates with the instrument shaft  1206 , any tendons connected to the drive inputs  1220  in the instrument base  1218  are not tangled during rotation. Accordingly, the parallelism of the axes of the drive outputs  1208 , the drive inputs  1220 , and the instrument shaft  1206  allows for the shaft rotation without tangling any control tendons. 
       FIG. 13  illustrates a medical instrument  1300  having an instrument based insertion architecture in accordance with some embodiments. The instrument  1300  (alternately referred to as a “surgical tool”) can be coupled to any of the instrument drivers discussed herein above and, as illustrated, can include an elongated shaft  1302 , an end effector  1304  connected to the shaft  1302 , and a handle  1306  coupled to the shaft  1302 . The elongated shaft  1302  comprises a tubular member having a proximal portion  1308   a  and a distal portion  1308   b.  The elongated shaft  1302  comprises one or more channels or grooves  1310  along its outer surface and configured to receive one or more wires or cables  1312  therethrough. One or more cables  1312  thus run along an outer surface of the elongated shaft  1302 . In other embodiments, the cables  1312  can also run through the elongated shaft  1302 . Manipulation of the cables  1312  (e.g., via an instrument driver) results in actuation of the end effector  1304 . 
     The instrument handle  1306 , which may also be referred to as an instrument base, may generally comprise an attachment interface  1314  having one or more mechanical inputs  1316 , e.g., receptacles, pulleys or spools, that are designed to be reciprocally mated with one or more drive outputs on an attachment surface of an instrument driver. 
     In some embodiments, the instrument  1300  comprises a series of pulleys or cables that enable the elongated shaft  1302  to translate relative to the handle  1306 . In other words, the instrument  1300  itself comprises an instrument-based insertion architecture that accommodates insertion of the instrument  1300 , thereby minimizing the reliance on a robot arm to provide insertion of the instrument  1300 . In other embodiments, a robotic arm can be largely responsible for instrument insertion. 
     E. Controller. 
     Any of the robotic systems described herein can include an input device or controller for manipulating an instrument attached to a robotic arm. In some embodiments, the controller can be coupled (e.g., communicatively, electronically, electrically, wirelessly and/or mechanically) with an instrument such that manipulation of the controller causes a corresponding manipulation of the instrument e.g., via master slave control. 
       FIG. 14  is a perspective view of an embodiment of a controller  1400 . In the present embodiment, the controller  1400  comprises a hybrid controller that can have both impedance and admittance control. In other embodiments, the controller  1400  can utilize just impedance or passive control. In other embodiments, the controller  1400  can utilize just admittance control. By being a hybrid controller, the controller  1400  advantageously can have a lower perceived inertia while in use. 
     In the illustrated embodiment, the controller  1400  is configured to allow manipulation of two medical instruments, and includes two handles  1402 . Each of the handles  1402  is connected to a gimbal  1404 , and each gimbal  1404  is connected to a positioning platform  1406 . 
     As shown in  FIG. 14 , each positioning platform  1406  includes a selective compliance assembly robot arm (SCARA)  1408  coupled to a column  1410  by a prismatic joint  1412 . The prismatic joints  1412  are configured to translate along the column  1410  (e.g., along rails  1414 ) to allow each of the handles  1402  to be translated in the z-direction, providing a first degree of freedom. The SCARA arm  1408  is configured to allow motion of the handle  1402  in an x-y plane, providing two additional degrees of freedom. 
     In some embodiments, one or more load cells are positioned in the controller  1400 . For example, in some embodiments, a load cell (not shown) is positioned in the body of each of the gimbals  1404 . By providing a load cell, portions of the controller  1400  are capable of operating under admittance control, thereby advantageously reducing the perceived inertia of the controller  1400  while in use. In some embodiments, the positioning platform  1406  is configured for admittance control, while the gimbal  1404  is configured for impedance control. In other embodiments, the gimbal  1404  is configured for admittance control, while the positioning platform  1406  is configured for impedance control. Accordingly, for some embodiments, the translational or positional degrees of freedom of the positioning platform  1406  can rely on admittance control, while the rotational degrees of freedom of the gimbal  1404  rely on impedance control. 
     F. Navigation and Control. 
     Traditional endoscopy may involve the use of fluoroscopy (e.g., as may be delivered through a C-arm) and other forms of radiation-based imaging modalities to provide endoluminal guidance to an operator physician. In contrast, the robotic systems contemplated by this disclosure can provide for non-radiation-based navigational and localization means to reduce physician exposure to radiation and reduce the amount of equipment within the operating room. As used herein, the term “localization” may refer to determining and/or monitoring the position of objects in a reference coordinate system. Technologies such as pre-operative mapping, computer vision, real-time EM tracking, and robot command data may be used individually or in combination to achieve a radiation-free operating environment. In other cases, where radiation-based imaging modalities are still used, the pre-operative mapping, computer vision, real-time EM tracking, and robot command data may be used individually or in combination to improve upon the information obtained solely through radiation-based imaging modalities. 
       FIG. 15  is a block diagram illustrating a localization system  1500  that estimates a location of one or more elements of the robotic system, such as the location of the instrument, in accordance to an example embodiment. The localization system  1500  may be a set of one or more computer devices configured to execute one or more instructions. The computer devices may be embodied by a processor (or processors) and computer-readable memory in one or more components discussed above. By way of example and not limitation, the computer devices may be in the tower  112  shown in  FIG. 1 , the cart  102  shown in  FIGS. 1-3B , the beds shown in  FIGS. 4-9 , etc. 
     As shown in  FIG. 15 , the localization system  1500  may include a localization module  1502  that processes input data  1504   a,    1504   b,    1504   c,  and  1504   d  to generate location data  1506  for the distal tip of a medical instrument. The location data  1506  may be data or logic that represents a location and/or orientation of the distal end of the instrument relative to a frame of reference. The frame of reference can be a frame of reference relative to the anatomy of the patient or to a known object, such as an EM field generator (see discussion below for the EM field generator). 
     The various input data  1504   a - d  are now described in greater detail. Pre-operative mapping may be accomplished through the use of the collection of low dose CT scans. Pre-operative CT scans are reconstructed into three-dimensional images, which are visualized, e.g. as “slices” of a cutaway view of the patient&#39;s internal anatomy. When analyzed in the aggregate, image-based models for anatomical cavities, spaces and structures of the patient&#39;s anatomy, such as a patient lung network, may be generated. Techniques such as center-line geometry may be determined and approximated from the CT images to develop a three-dimensional volume of the patient&#39;s anatomy, referred to as model data  1504   a  (also referred to as “preoperative model data” when generated using only preoperative CT scans). The use of center-line geometry is discussed in U.S. patent application Ser. No. 14/523,760, the contents of which are herein incorporated in its entirety. Network topological models may also be derived from the CT-images, and are particularly appropriate for bronchoscopy. 
     In some embodiments, the instrument may be equipped with a camera to provide vision data  1504   b.  The localization module  1502  may process the vision data  1504   b  to enable one or more vision-based location tracking. For example, the preoperative model data may be used in conjunction with the vision data  1504   b  to enable computer vision-based tracking of the medical instrument (e.g., an endoscope or an instrument advance through a working channel of the endoscope). For example, using the preoperative model data  1504   a,  the robotic system may generate a library of expected endoscopic images from the model based on the expected path of travel of the endoscope, each image linked to a location within the model. Intra-operatively, this library may be referenced by the robotic system in order to compare real-time images captured at the camera (e.g., a camera at a distal end of the endoscope) to those in the image library to assist localization. 
     Other computer vision-based tracking techniques use feature tracking to determine motion of the camera, and thus the endoscope. Some features of the localization module  1502  may identify circular geometries in the preoperative model data  1504   a  that correspond to anatomical lumens and track the change of those geometries to determine which anatomical lumen was selected, as well as the relative rotational and/or translational motion of the camera. Use of a topological map may further enhance vision-based algorithms or techniques. 
     Optical flow, another computer vision-based technique, may analyze the displacement and translation of image pixels in a video sequence in the vision data  1504   b  to infer camera movement. Examples of optical flow techniques may include motion detection, object segmentation calculations, luminance, motion compensated encoding, stereo disparity measurement, etc. Through the comparison of multiple frames over multiple iterations, movement and location of the camera (and thus the endoscope) may be determined. 
     The localization module  1502  may use real-time EM tracking to generate a real-time location of the endoscope in a global coordinate system that may be registered to the patient&#39;s anatomy, represented by the preoperative model. In EM tracking, an EM sensor (or tracker) comprising of one or more sensor coils embedded in one or more locations and orientations in a medical instrument (e.g., an endoscopic tool) measures the variation in the EM field created by one or more static EM field generators positioned at a known location. The location information detected by the EM sensors is stored as EM data  1504   c.  The EM field generator (or transmitter), may be placed close to the patient to create a low intensity magnetic field that the embedded sensor may detect. The magnetic field induces small currents in the sensor coils of the EM sensor, which may be analyzed to determine the distance and angle between the EM sensor and the EM field generator. These distances and orientations may be intra-operatively “registered” to the patient anatomy (e.g., the preoperative model) in order to determine the geometric transformation that aligns a single location in the coordinate system with a position in the pre-operative model of the patient&#39;s anatomy. Once registered, an embedded EM tracker in one or more positions of the medical instrument (e.g., the distal tip of an endoscope) may provide real-time indications of the progression of the medical instrument through the patient&#39;s anatomy. 
     Robotic command and kinematics data  1504   d  may also be used by the localization module  1502  to provide localization data  1506  for the robotic system. Device pitch and yaw resulting from articulation commands may be determined during pre-operative calibration. Intra-operatively, these calibration measurements may be used in combination with known insertion depth information to estimate the position of the instrument. Alternatively, these calculations may be analyzed in combination with EM, vision, and/or topological modeling to estimate the position of the medical instrument within the network. 
     As  FIG. 15  shows, a number of other input data can be used by the localization module  1502 . For example, although not shown in  FIG. 15 , an instrument utilizing shape-sensing fiber can provide shape data that the localization module  1502  can use to determine the location and shape of the instrument. 
     The localization module  1502  may use the input data  1504   a - d  in combination(s). In some cases, such a combination may use a probabilistic approach where the localization module  1502  assigns a confidence weight to the location determined from each of the input data  1504   a - d.  Thus, where the EM data  1504   c  may not be reliable (as may be the case where there is EM interference) the confidence of the location determined by the EM data  1504   c  can be decrease and the localization module  1502  may rely more heavily on the vision data  1504   b  and/or the robotic command and kinematics data  1504   d.    
     As discussed above, the robotic systems discussed herein may be designed to incorporate a combination of one or more of the technologies above. The robotic system&#39;s computer-based control system, based in the tower, bed and/or cart, may store computer program instructions, for example, within a non-transitory computer-readable storage medium such as a persistent magnetic storage drive, solid state drive, or the like, that, upon execution, cause the system to receive and analyze sensor data and user commands, generate control signals throughout the system, and display the navigational and localization data, such as the position of the instrument within the global coordinate system, anatomical map, etc. 
     2. Description. 
       FIG. 16  is an isometric side view of an example surgical tool  1600  that may incorporate some or all of the principles of the present disclosure. The surgical tool  1600  may be similar in some respects to any of the surgical tools and medical instruments described above with reference to  FIGS. 11-13  and, therefore, may be used in conjunction with a robotic surgical system, such as the robotically-enabled systems  100 ,  400 , and  900  of  FIGS. 1-9C . As illustrated, the surgical tool  1600  includes an elongated shaft  1602 , an end effector  1604  arranged at the distal end of the shaft  1602 , and an articulable wrist  1606  (alternately referred to as a “wrist joint”) that interposes and couples the end effector  1604  to the distal end of the shaft  1602 . In some embodiments, the wrist  1606  may be omitted, without departing from the scope of the disclosure. 
     The terms “proximal” and “distal” are defined herein relative to a robotic surgical system having an interface configured to mechanically and electrically couple the surgical tool  1600  to a robotic manipulator. The term “proximal” refers to the position of an element closer to the robotic manipulator and the term “distal” refers to the position of an element closer to the end effector  1604  and thus closer to the patient during operation. Moreover, the use of directional terms such as above, below, upper, lower, upward, downward, left, right, and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward or upper direction being toward the top of the corresponding figure and the downward or lower direction being toward the bottom of the corresponding figure. 
     The surgical tool  1600  can have any of a variety of configurations capable of performing one or more surgical functions. In the illustrated embodiment, the end effector  1604  comprises a surgical stapler, alternately referred to as an “endocutter,” configured to simultaneously cut and staple (fasten) tissue. As illustrated, the end effector  1604  includes opposing jaws  1610 ,  1612  configured to move (articulate) between open and closed positions. Alternatively, the end effector  1604  may comprise other types of instruments with opposing jaws such as, but not limited to, other types of surgical staplers (e.g., circular and linear staplers), tissue graspers, surgical scissors, advanced energy vessel sealers, clip appliers, needle drivers, a babcock including a pair of opposed grasping jaws, bipolar jaws (e.g., bipolar Maryland grasper, forceps, a fenestrated grasper, etc.), etc. In other embodiments, the end effector  1604  may instead comprise any end effector or instrument capable of being operated in conjunction with the presently disclosed robotic surgical systems and methods, such as a suction irrigator, an endoscope (e.g., a camera), or any combination thereof. 
     One or both of the jaws  1610 ,  1612  may be configured to pivot to actuate the end effector  1604  between open and closed positions. In the illustrated example, the second jaw  1612  may be rotatable (pivotable) relative to the first jaw  1610  to actuate the end effector  1604  between an open, unclamped position and a closed, clamped position. In other embodiments, however, the first jaw  1610  may move (rotate) relative to the second jaw  1612  to move the jaws  1610 ,  1612  between open and closed positions. In yet other embodiments, the jaws  1610 ,  1612  may comprise bifurcating jaws where both jaws  1610 ,  1612  move simultaneously between open and closed positions. 
     In the illustrated example, the first jaw  1610  is referred to as a “cartridge” or “channel” jaw, and the second jaw  1612  is referred to as an “anvil” jaw. The first jaw  1610  includes a frame that houses or supports a staple cartridge, and the second jaw  1612  is pivotally supported relative to the first jaw  1610  and defines a surface that operates as an anvil to deform staples ejected from the staple cartridge during operation. 
     The wrist  1606  enables the end effector  1604  to articulate (pivot) relative to the shaft  1602  and thereby position the end effector  1604  at various desired orientations and locations relative to a surgical site. In the illustrated embodiment, the wrist  1606  is designed to allow the end effector  1604  to pivot (swivel) left and right relative to a longitudinal axis A 1  of the shaft  1602 . In other embodiments, however, the wrist  1606  may be designed to provide multiple degrees of freedom, including one or more translational variables (i.e., surge, heave, and sway) and/or one or more rotational variables (i.e., Euler angles or roll, pitch, and yaw). The translational and rotational variables describe the position and orientation of a component of a surgical system (e.g., the end effector  1604 ) with respect to a given reference Cartesian frame. “Surge” refers to forward and backward translational movement, “heave” refers to translational movement up and down, and “sway” refers to translational movement left and right. With regard to the rotational terms, “roll” refers to tilting side to side, “pitch” refers to tilting forward and backward, and “yaw” refers to turning left and right. 
     The end effector  1604  is depicted in  FIG. 16  in the unarticulated position where the longitudinal axis of the end effector  1604  is substantially aligned with the longitudinal axis A 1  of the shaft  1602 , such that the end effector  1604  is at a substantially zero angle relative to the shaft  1602 . In an articulated position, the longitudinal axis of the end effector  1604  would be angularly offset from the longitudinal axis A 1  such that the end effector  1604  would be oriented at a non-zero angle relative to the shaft  1602 . 
     Still referring to  FIG. 16 , the surgical tool  1600  may also include a drive housing or “handle”  1614 , and the shaft  1602  extends longitudinally through the handle  1614 . The handle  1614  houses an actuation system designed to move the shaft  1602  relative to the handle  1614  in z-axis translation. Other actuation systems housed within the handle  1614  may be designed to facilitate articulation of the wrist  1606  and actuation (operation) of the end effector  1604  (e.g., clamping, firing, rotation, articulation, energy delivery, etc.). In some embodiments, the actuation systems and mechanisms housed within the handle  1614  may be actuatable to move (translate) a plurality of drive members (mostly obscured in  FIG. 16 ) that extend along at least a portion of the shaft  1602 , either on the exterior or within the interior of the shaft  1602 . Example drive members include, but are not limited to, cables, bands, lines, cords, wires, woven wires, ropes, strings, twisted strings, elongate members, belts, shafts, flexible shafts, drive rods, or any combination thereof. The drive members can be made from a variety of materials including, but not limited to, a metal (e.g., tungsten, stainless steel, nitinol, etc.) a polymer (e.g., ultra-high molecular weight polyethylene), a synthetic fiber (e.g., KEVLAR®, VECTRAN®, etc.), an elastomer, or any combination thereof. 
     Selective actuation of one or more of the drive members, for example, may cause the shaft  1602  to translate relative to the handle  1614 , as indicated by the arrows B (i.e., z-axis translation), and thereby advance or retract the end effector  1602 . Selective actuation of one or more other drive members may cause the end effector  1604  to articulate (pivot) relative to the shaft  1602  at the wrist  1606 . Selective actuation of one or more additional drive members may cause the end effector  1604  to actuate (operate). Actuating the end effector  1604  depicted in  FIG. 16  may entail closing and/or opening the jaws,  1610 ,  1612  and thereby enabling the end effector  1604  to grasp (clamp) onto tissue. Once tissue is grasped or clamped between the opposing jaws  1610 ,  1612 , actuating the end effector  1604  may further include “firing” the end effector  1604 , which may refer to causing a cutting element or knife (not visible) to advance distally within a slot or “guide track”  1616  defined in the first jaw  1610 . As it moves distally, the knife transects any tissue grasped between the opposing jaws  1610 ,  1612 , and a plurality of staples contained within the staple cartridge (e.g., housed within the first jaw  1610 ) are simultaneously urged (cammed) into deforming contact with corresponding anvil surfaces (e.g., pockets) provided on the second jaw  1612 . The deployed staples may form multiple rows of staples that seal opposing sides of the transected tissue. 
     As will be appreciated, however, the end effector  1604  may be replaced with any of the other types of end effectors mentioned herein, and in those cases actuating the end effector  1604  may entail a variety of other actions or movements, without departing from the scope of the disclosure. For example, in some embodiments, the end effector  1604  may be replaced with a vessel sealer and actuating the vessel sealer may further entail triggering energy delivery (e.g., RF energy) to cauterize and/or seal tissue or vessels. 
     The handle  1614  provides or otherwise includes various coupling features that releasably couple the surgical tool  1600  to an instrument driver  1618  (shown in dashed lines) of a robotic surgical system. The instrument driver  1618  may be similar in some respects to the instrument drivers  1102 ,  1200  of  FIGS. 11 and 12 , respectively, and therefore may be best understood with reference thereto. Similar to the instrument drivers  1102 ,  1200 , for example, the instrument driver  1618  may be mounted to or otherwise positioned at the end of a robotic arm (not shown) and is designed to provide the motive forces required to operate the surgical tool  1600 . Unlike the instrument drivers  1102 ,  1200 , however, the shaft  1602  of the surgical tool  1600  extends through and penetrates the instrument driver  1618 . 
     The handle  1614  includes one or more rotatable drive inputs matable with one or more corresponding drive outputs (not shown) of the instrument driver  1618 . Each drive input is actuatable to independently drive (actuate) the actuation systems and mechanisms housed within the handle  1614  and thereby operate the surgical tool  1600 . In the illustrated embodiment, the handle  1614  includes a first drive input  1620   a,  a second drive input  1620   b,  a third drive input  1620   c,  a fourth drive input  1620   d,  a fifth drive input  1620   e,  and a sixth drive input  1620   f.  While six drive inputs  1620   a - f  are depicted, more or less than six may be included in the handle  1614  depending on the application, and without departing from the scope of the disclosure. Each drive input  1620   a - f  may be matable with a corresponding drive output (not shown) of the instrument driver  1618  such that movement (rotation) of a given drive output correspondingly moves (rotates) the associated drive input  1620   a - f  and thereby causes various operations of the surgical tool  1600 . 
     In some embodiments, actuation of the first drive input  1620   a  may cause the knife to fire at the end effector  1604 , thus advancing or retracting the knife, depending on the rotational direction of the first drive input  1620   a.  Actuation of the third drive input  1620   c  may cause the shaft  1602  to move (translate) relative to the handle  1614  along the longitudinal axis A 1 , depending on the rotational direction of the third drive input  1620   c.  In some embodiments, actuation of the second drive input  1620   b  may shift operation or activation within the handle  1614  between the first and third drive inputs  1620   a,c.  Consequently, actuation of the second drive input  1620   b  will dictate whether the knife is fired or whether the shaft  1602  is moved (translated). Actuation of the fourth drive input  1620   d  may lock and unlock z-axis translation of the shaft  1602 , and, as described in more detail herein, actuation of the fifth drive input  1620   e  may cause articulation of the end effector  1604  at the wrist  1606 . Lastly, actuation of the sixth drive input  1620   f  may cause the jaws  1610 ,  1612  to open or close, depending on the rotational direction of the sixth drive input  1620   f.  In some embodiments, as also described in more detail herein, actuation of the sixth drive input  1620   f  may operate a toggle mechanism  1622  arranged at the proximal end of the shaft  1602 , and actuation of the toggle mechanism  1622  may cause the jaws  1610 ,  1612  to open and close. 
       FIG. 17  depicts separated isometric end views of the instrument driver  1618  and the surgical tool  1600  of  FIG. 16 . With the jaws  1610 ,  1612  closed, the shaft  1602  and the end effector  1604  can penetrate the instrument driver  1618  by extending through a central aperture  1702  defined longitudinally through the instrument driver  1618  between first and second ends  1704   a,b.  In some embodiments, to align the surgical tool  1600  with the instrument driver  1618  in a proper angular orientation, one or more alignment guides  1706  may be provided or otherwise defined within the central aperture  1702  and configured to engage one or more corresponding alignment features (not shown) provided on the surgical tool  1600 . The alignment feature(s) may comprise, for example, a protrusion or projection (not shown) defined on or otherwise provided by an alignment nozzle  1708  extending distally from the handle  1614 . In one or more embodiments, the alignment guide(s)  1706  may comprise a curved or arcuate shoulder or lip configured to receive and guide the alignment feature as the alignment nozzle  1708  enters the central aperture  1702 . As a result, the surgical tool  1600  is oriented to a proper angular alignment with the instrument driver  1618  as the alignment nozzle  1708  is advanced distally through the central aperture  1702 . In other embodiments, the alignment nozzle  1708  may be omitted and the alignment feature  1712  may alternatively be provided on the shaft  1602 , without departing from the scope of the disclosure. 
     A drive interface  1710  is provided at the first end  1704   a  of the instrument driver  1618  and is matable with a driven interface  1712  provided on the distal end of the handle  1614 . The drive and driven interfaces  1710 ,  1712  may be configured to mechanically, magnetically, and/or electrically couple the handle  1614  to the instrument driver  1618 . To accomplish this, in some embodiments, the drive and driven interfaces  1710 ,  1712  may provide one or more matable locating features configured to secure the handle  1614  to the instrument driver  1618 . In the illustrated embodiment, for example, the drive interface  1710  provides one or more interlocking features  1714  (three shown) configured to locate and mate with one or more complementary-shaped pockets  1716  (two shown, one occluded) provided on the driven interface  1712 . In some embodiments, the features  1714  may be configured to align and mate with the pockets  1716  via an interference or snap fit engagement, for example. 
     The instrument driver  1618  also includes one or more drive outputs that extend through the drive interface  1710  to mate with corresponding drive inputs  1620   a - f  provided at the distal end of the handle  1614 . More specifically, the instrument driver  1618  includes a first drive output  1718   a  matable with the first drive input  1620   a,  a second drive output  1718   b  matable with the second drive input  1620   b,  a third drive output  1718   b  matable with the third drive input  1620   c,  a fourth drive output  1718   d  matable with the fourth drive input  1620   d,  a fifth drive output  1718   e  matable with the fifth drive input  1620   e,  and a sixth drive output  1718   f  matable with the sixth drive input  1620   f.  In some embodiments, as illustrated, the drive outputs  1718   a - f  may define splines or features designed to mate with corresponding splined receptacles of the drive inputs  1620   a - f.  Once properly mated, the drive inputs  1620   a - f  will share axes of rotation with the corresponding drive outputs  1718   a - f  to allow the transfer of rotational torque from the drive outputs  1718   a - f  to the corresponding drive inputs  1620   a - f.  In some embodiments, each drive output  1718   a - f  may be spring loaded and otherwise biased to spring outwards away from the drive interface  1710 . Each drive output  1718   a - f  may be capable of partially or fully retracting into the drive interface  1710 . 
     In some embodiments, the instrument driver  1618  may include additional drive outputs, depicted in  FIG. 17B  as a seventh drive output  1718   g.  The seventh drive output  1718   g  may be configured to mate with additional drive inputs (not shown) of the handle  1614  to help undertake one or more additional functions of the surgical tool  1600 . In the illustrated embodiment, however, the handle  1614  does not include additional drive inputs matable with the seventh drive output  1718   g.  Instead, the driven interface  1712  defines a corresponding recess  1720  (partially occluded) configured to receive the seventh drive output  1718   g.  In other applications, however, a seventh drive input (not shown) could be included in the handle  1614  to mate with the seventh drive output  1718   g,  or the surgical tool  1600  might be replaced with another surgical tool having a seventh drive input, which would be driven by the seventh drive output  1718   g.    
     While not shown, in some embodiments, an instrument sterile adapter (ISA) may be placed at the interface between the instrument driver  1618  and the handle  1614 . In such applications, the interlocking features  1714  may operate as alignment features and possible latches for the ISA to be placed, stabilized, and secured. Stability of the ISA may be accomplished by a nose cone feature provided by the ISA and extending into the central aperture  1702  of the instrument driver  1618 . Latching can occur either with the interlocking features  1714  or at other locations at the interface. In some cases, the ISA will provide the means to help align and facilitate the latching of the surgical tool  1600  to the ISA and simultaneously to the instrument driver  1618 . 
     Shaft Proximal End Load Reduction Linkage for a Cable Driven Jaw Closure System 
       FIG. 18  is an enlarged isometric view of the handle  1614  of  FIGS. 16-17  and depicting an example actuation system  1800 , according to one or more embodiments. The outer body of the handle  1614  is shown in phantom to enable viewing of the internal mechanisms and components housed within the handle  1614 , including the actuation system  1800 . Various other actuation systems and component parts of the handle  1614  are omitted in  FIG. 18  for simplicity. 
     The actuation system  1800  may alternately be referred to as an “accumulator system” or “cable differential system”. According to one or more embodiments, the actuation system  1800  may be operable (actuatable) to open and close the jaws  1610 ,  1612  ( FIGS. 16-17 ) at the end effector  1604  ( FIG. 16 ). Accordingly, the actuation system  1800  may include or otherwise be operatively coupled to the sixth drive input  1620   f,  as briefly mentioned above. Depending on the rotational direction of the sixth drive input  1620   f,  via operation of the sixth drive output  1718   f  ( FIG. 17 ), the jaws  1610 ,  1612  may be actuated to open or allowed to close. In other embodiments, however, the actuation system  1800  may be designed to carry out other functions (operations) of the surgical tool  1600  ( FIG. 16 ) or the end effector  1604 , such as causing the shaft  1602  to translate relative to the handle  1614 , causing the end effector  1604  to articulate, or causing the end effector  1604  to “fire,” without departing from the scope of this disclosure. 
     As illustrated, the actuation system  1800  includes an accumulator  1802  coupled to a drive shaft  1804  extending from the sixth drive input  1620   f.  The drive shaft  1804  may be coupled to or form part of the sixth drive input  1620   f  such that rotation of the sixth drive input  1620   f  correspondingly rotates the drive shaft  1804  and simultaneously rotates the accumulator  1802  in the same angular direction. 
     The accumulator  1802  may include a body  1806  coupled to or forming part of the drive shaft  1804 , and the body  1806  may interpose a first or “upper” accumulator pulley  1808   a  and a second or “lower” accumulator pulley  1808   b.  The upper and lower accumulator pulleys  1808   a,b  may be rotatably mounted to the drive shaft  1804  and axially offset from each other, thus sharing the same axis of rotation. The accumulator  1802  may further include a third or “side” accumulator pulley  1808   c  laterally offset from the upper and lower accumulator pulleys  1808   a,b.  The side accumulator pulley  1808   c,  for example, may be rotatably mounted to a lateral arm  1810  extending from the body  1806 . 
     The actuation system  1800  may further include a drive member  1812  that extends longitudinally along at least a portion of the shaft  1602 . In the illustrated embodiment, the drive member  1812  comprises a cable or wire and, therefore, will be referred to herein as “the drive cable  1812 ”. In other embodiments, however, the drive cable  1812  may comprise any of the other types of drive members mentioned herein. As illustrated, the drive cable  1812  may be received and extend within a groove  1814  defined in the shaft  1602 . In other embodiments, however, the drive cable  1812  may alternatively be received within the interior of the shaft  1602  or extend along an exterior surface of the shaft  1602 , without departing from the scope of the disclosure. 
     A first or “distal” end  1816   a  of the drive cable  1812  may be anchored to the shaft  1602  below (distal to) the handle  1614 , and a second or “proximal” end  1816   b  (see  FIG. 19 ) of the drive cable  1812  may be anchored to the shaft  1602  above (proximal to) the handle  1614 . In some embodiments, the proximal end  1816   b  of the drive cable  1812  may be anchored at or near a proximal end of the shaft  1602  and adjacent the toggle mechanism  1622  ( FIGS. 16 and 19 ). As discussed in more detail below, actuation of the accumulator  1802  may cause the drive cable  1812  to act on the toggle mechanism  1622 , which may be designed to open and close the jaws  1610 ,  1612  ( FIGS. 16-17 ). 
     As illustrated, the drive cable  1812  may also extend or be threaded (guided) through the accumulator  1802  within the body of the handle  1614 . The actuation system  1800  may further include a first or “upper” idler pulley  1818   a  and a second or “lower” idler pulley  1818   b.  The upper and lower idler pulleys  1818   a,b  may each be rotatably coupled to the handle  1614 . The upper idler pulley  1818   a  may be arranged and otherwise configured to redirect the drive cable  1812  between the shaft  1602  and the upper accumulator pulley  1808   a,  and the lower idler pulley  1818   b  may be arranged and otherwise configured to redirect the drive cable  1812  between the shaft  1602  and the lower accumulator pulley  1808   b.    
     The side accumulator pulley  1808   c  may be arranged to receive and redirect the drive cable  1812  between the upper and lower accumulator pulleys  1808   a,b.  More specifically, in some embodiments, the upper and lower accumulator pulleys  1808   a,b  may be arranged for rotation in respective parallel planes, while the side accumulator pulley  1808   c  may be arranged for rotation in a plane that is 90° offset from the parallel planes in order to redirect the drive cable  1812  between the upper and lower accumulator pulleys  1808   a,b.  In one embodiment, for example, the parallel planes of the upper and lower accumulator pulleys  1808   a,b  may be characterized as extending substantially horizontal, and the plane of the side accumulator pulley  1808   c  may be characterized as extending substantially vertical and otherwise 90° offset from the horizontal planes. In other embodiments, however, the planes of the upper and lower accumulator pulleys  1808   a,b  and the side accumulator pulley  1808   c  need not be 90° offset from each other. Moreover, the upper and lower accumulator pulleys  1808   a,b  need not be arranged for rotation in respective parallel planes, but may alternatively be arranged in non-parallel planes, without departing from the scope of the disclosure. 
     As mentioned above, the actuation system  1800  may be actuated or operated by rotating the sixth drive input  1620   f,  via operation of the sixth drive output  1718   f  ( FIG. 17 ). Rotating the sixth drive input  1620   f  in a first angular direction C will correspondingly rotate the drive shaft  1804  and the accumulator  1802  in the same direction C and about the same rotational axis. Because the distal end  1816   a  of the drive cable  1812  is anchored to the shaft  1602  distal to the handle  1614 , the drive cable  1812  may be drawn (pulled) into the accumulator  1802  at the upper accumulator pulley  1808   a  as the accumulator  1802  rotates in the direction C. This is shown by the arrow D. Upon releasing the torque at the sixth drive input  1620   f,  or otherwise reversing the direction of the sixth drive output  1718   f,  the drive shaft  1804  and the accumulator  1802  will rotate opposite the direction C, and a length of the drive cable  1812  may correspondingly be paid out (fed) to the shaft  1602  from the upper accumulator pulley  1808   a  in a direction opposite the arrow D. As discussed in more detail below, drawing or paying out the drive cable  1812  into or from the accumulator  1802  correspondingly acts on the toggle mechanism  1622  ( FIGS. 16 and 19 ) at the proximal end of the shaft  1602 , and operation of the toggle mechanism  1622  may result in the jaws  1610 ,  1612  ( FIGS. 16-17 ) closing or opening, depending on the direction of the drive cable  1812 . 
     In some embodiments, the actuation system  1800  may be decoupled from shaft  1602  insertion. More specifically, the accumulator pulleys  1808   a - c  and the idler pulleys  1818   a,b  are able to freely rotate (e.g., “free wheel”) and are otherwise not driven during operation of the handle  1614 . Consequently, as the shaft  1602  moves longitudinally relative to the handle  1614  in z-axis translation, the drive cable  1812  is able to freely run (course) through the accumulator  1802  between the upper and lower idler pulleys  1818   a,b.  Moreover, since the accumulator pulleys  1808   a - c  and the idler pulleys  1818   a,b  are able to freely rotate, the actuation system  1800  can be operated simultaneously during shaft  1602  translation. 
       FIG. 19  is an enlarged, isometric side view of the toggle mechanism  1622  of  FIG. 16 , according to one or more embodiments of the present disclosure. As illustrated, the toggle mechanism  1622  may be arranged at or near a proximal end  1902  of the shaft  1602 . The drive cable  1812  extends from the handle  1614  ( FIG. 18 ) to the toggle mechanism  1622 , and the proximal end  1816   b  of the drive cable  1812  may be secured (anchored) to the shaft  1602  at or near the proximal end  1902 . In at least one embodiment, the drive cable  1812  may be secured to the shaft  1602  at a cable anchoring location  1904  coupled to or forming part of the shaft  1602 . 
     In some embodiments, the toggle mechanism  1622  may comprise a two-bar linkage system. More specifically, the toggle mechanism  1622  may include a first or “proximal” link  1906   a  and a second or “distal” link  1906   b  rotatably coupled to the proximal link  1906   a  at a hinge joint  1908 . The hinge joint  1908  may include a first axle  1910   a  that couples the proximal and distal links  1906   a,b,  and the first axle  1910   a  may extend along a first pivot axis P 1 . During operation of the toggle mechanism  1622 , the proximal and distal links  1906   a,b  may be configured to pivot about the first pivot axis P 1 . 
     The proximal link  1906   a  may also be rotatably coupled to the shaft  1602  and, more particularity, to a tail piece  1912  secured to the shaft  1602  at or near the proximal end  1902 . The proximal link  1906   a  may be rotatably coupled to the tail piece  1912  at a second axle  1910   b  through which a second pivot axis P 2  extends. Moreover, the distal link  1906   b  may also be rotatably coupled to a pusher member  1914  and pivotable about a third pivot axis P 3  extending through the distal link  1906   b  and the pusher member  1914 . In some embodiments, the first, second, and third pivot axes P 1-3  may be substantially parallel to each other. 
     The pusher member  1914  may be mounted to the shaft  1602  and, more particularly, to a movable shaft portion  1916  that forms part of the shaft  1602 . The pusher member  1914  may be engageable with the movable shaft portion  1916  such that longitudinal movement of the pusher member  1914  resulting from movement of the distal link  1906   b  may correspondingly move the movable shaft portion  1916  in the same axial direction. While forming part of the shaft  1602 , the movable shaft portion  1916  may be able to translate longitudinally relative to remaining portions of the shaft  1602  as acted upon by the pusher member  1914 . The movable shaft portion  1916  extends distally and is operatively coupled (either directly or indirectly) to a closure tube  2006  (see  FIG. 20 ), which may comprise an outer portion of the shaft  1602  that extends to the end effector  1604  ( FIGS. 16 and 20 ). 
     The toggle mechanism  1622  may further include various pulleys configured to receive and redirect the drive cable  1812 . In the illustrated embodiment, for example, the toggle mechanism  1622  includes first and second linkage pulleys  1918   a  and  1918   b.  The first linkage pulley  1918   a  may be rotatably mounted to the first axle  1910   a  at the hinge joint  1908 . The first linkage pulley  1918   a  receives the drive cable  1812  from the second linkage pulley  1918   b  and feeds the drive cable  1812  to the cable anchoring location  1904 . The second linkage pulley  1918   b  may be secured to the shaft  1602  at or near the proximal end  1902 . In at least one embodiment, however, the second linkage pulley  1918   b  may be omitted from the toggle mechanism  1622  and the drive cable  1812  may be fed directly to the first linkage pulley  1918   a,  without departing from the scope of the disclosure. 
     The toggle mechanism  1622  may be movable (pivotable) between a first or “actuated” position, where the hinge joint  1908  is moved (pivoted) toward the shaft  1602 , and a second or “extended” position, where the hinge joint  1908  is moved (pivoted) away from the shaft  1602 . The hinge joint  1908  is depicted in  FIG. 19  at a point between the actuated and extended positions. Moving (pivoting) the toggle mechanism  1622  to the actuated position will cause the jaws  1610 ,  1612  ( FIGS. 16-17 ) at the end effector  1604  ( FIG. 16 ) to close, and moving (pivoting) the toggle mechanism  1622  to the extended position will cause (or allow) the jaws  1610 ,  1612  to open. 
     In some embodiments, the toggle mechanism  1622  may be moved (transitioned) to the actuated position through actuation and operation of the actuation system  1800  of  FIG. 18 . More specifically, as the actuation system  1800  is actuated, as generally described above, the drive cable  1812  may be drawn by the rotating accumulator  1802  (FIG.  18 ) and correspondingly pulled distally along the shaft  1602 , as shown by the arrow E. As the drive cable  1812  is pulled distally E, and since it is anchored to the shaft  1602  at the cable anchoring location  1904 , the drive cable  1812  will act on the hinge joint  1908  at the first linkage pulley  1918   a  and correspondingly urge (pull) the hinge joint  1908  toward the shaft  1602  and the actuated position, as shown by the arrow F. As the hinge joint  1908  moves toward the actuated position, the distal link  1906   b  may correspondingly drive (move) the pusher member  1914  distally E, which correspondingly moves the movable shaft portion  1916  in the same direction. Moving the movable shaft portion  1916  distally E may act on the closure tube  2006  ( FIG. 20 ) to close the jaws  1610 ,  1612  ( FIGS. 16 and 20 ) at the end effector  1604  ( FIGS. 16 and 20 ). 
     As will be appreciated, the toggle mechanism  1622  may provide a mechanical advantage. More specifically, because work=force x distance, as the proximal and distal links  1906   a,b  approach 0° relative to each other (e.g., straight), the distance that affects translation of the shaft portion  1916  is smaller, thus allowing more force. Consequently, the force/torque required by the drive input  1620   f  ( FIG. 18 ) to cause actuation of the toggle mechanism  1622  is decreased to effectuate the end effector jaw closure. For example, the force to close the jaws  1610 ,  1612  ( FIGS. 16 and 20 ) may need 200 lbs of pull force, and the input torque to operate the toggle mechanism  1622  to generate that 200 lbs of pull is less due to the mechanical advantage of the toggle mechanism  1622 . The load on the drive input  1620   f  can be more or less depending on the moment arms (e.g., layout of the hinge joint  1908 ) of the toggle mechanism  1622 . Accordingly, mechanical advantage increases with stroke during operation. In other words, the relationship between force and distance may be intentionally varied throughout the stroke; e.g., small input=large distance output at the beginning of the stroke, and large input=small distance output at the end of the stroke. This amplifies mechanical advantage and load application when the jaws  1610 ,  1612  ( FIGS. 16 and 20 ) are nearing close and compressing against the resistance of tissue grasped between the jaws  1610 ,  1612 . 
     Upon disengaging (ceasing) operation of the actuation system  1800  ( FIG. 18 ), or otherwise reversing operation of the actuation system  1800 , tension in the drive cable  1812  in the distal direction E may be released. The drive cable  1812  may then be able to be paid out of the accumulator  1802  ( FIG. 18 ) to the shaft  1602  and allowed to be drawn (moved) proximally along the shaft  1602 , as shown by the arrow G. In some embodiments, the toggle mechanism  1622  may be naturally biased toward the extended position and, therefore, continuously urged away from the shaft  1602 , as shown by the arrow H. In such embodiments, for example, the hinge joint  1908  may be spring loaded or otherwise include one or more torsion springs  1920  (one shown in dashed lines) that act on the hinge joint  1908  to urge the links  1906   a,b  to pivot away from the shaft  1602  to the natural position. As the hinge joint  1908  moves in the direction H toward the extended position, the drive cable  1812  is correspondingly drawn (pulled) proximally G. Moreover, as the hinge joint  1908  moves to the extended position, the distal link  1906   b  may correspondingly pull (move) the pusher member  1914  proximally G, which correspondingly moves the movable shaft portion  1916  in the same direction. Moving the movable shaft portion  1916  proximally G may act on the closure tube  2006  ( FIG. 20 ) and allow the jaws  1610 ,  1612  ( FIGS. 16 and 20 ) at the end effector  1604  ( FIGS. 16 and 20 ) to open. 
     Referring now to  FIG. 20 , with continued reference to  FIGS. 18-19 , depicted is an enlarged isometric view of the end effector  1604  and the wrist  1606 , according to one or more embodiments. As illustrated, the wrist  1606  may include a first or “proximal” clevis  2002   a,  a second or “distal” clevis  2002   b,  and a closure link  2004  configured to operatively couple the proximal and distal devises  2002   a,b  across the wrist  1606 . The proximal clevis  2002   a  may be coupled to or otherwise form part of the distal end of a closure tube  2006 , which, as discussed above, may form an outer portion of the shaft  1602  ( FIGS. 16-19 ) and may be operatively coupled (either directly or indirectly) to the movable shaft portion  1916  ( FIG. 19 ). The distal clevis  2002   b  may be coupled to or otherwise form part of a closure ring  2008  arranged adjacent the jaws  1610 ,  1612 . 
     Axial movement of the closure tube  2006  along the longitudinal axis A 1 , as acted upon by the movable shaft portion  1916  ( FIG. 19 ) as generally described above, correspondingly moves the proximal clevis  2002   a  in the same axial direction. The closure link  2004  may be configured to transmit the axial load through (across) the wrist  1606  to close the jaws  1610 ,  1612  of the end effector  1604 . More specifically, the closure link  2004  defines a pair of pins  2010  configured to mate with corresponding apertures  2012  defined in each of the proximal and distal devises  2002   a,b.  The closure link  2004  may transmit the closure load or translation movement of the closure tube  2006  from the distal clevis  2002   b  to the proximal clevis  2002   a  and the closure ring  2008  will correspondingly push or pull on the upper jaw  1612  to close or open the upper jaw  1612 . To close the upper jaw  1612 , the closure ring  2008  is forced distally against a shoulder  2014  at or near the back of the upper jaw  1612 , which urges the upper jaw  1612  to pivot down and to the closed position. To open the upper jaw  1612 , the closure ring  2008  is retracted proximally away from the shoulder  2014  by retracting the closure tube  2006 . 
     In some embodiments, proximal movement of the closure ring  2008  helps pull the upper jaw  1612  back toward the open position. In other embodiments, however, the upper jaw  1612  may be spring loaded and biased to the open position. In such embodiments, the spring force of the upper jaw  1612  may be sufficient to retract the closure ring  2008  and the closure tube  2006 . Moreover, in such embodiments, the spring force of the upper jaw  1612  may be sufficient to move (transition) the toggle mechanism  1622  ( FIG. 19 ) toward the extended position through interconnection of the closure tube  2006 , the movable shaft portion  1916  ( FIG. 19 ), the pusher member  1914  ( FIG. 19 ), and the distal link  1906   b  ( FIG. 19 ). Alternatively, both the hinge joint  1908  ( FIG. 19 ) and the upper jaw  1612  may be spring loaded to cooperatively urge the toggle mechanism  1622  toward the extended position. 
     Robotic Instrument with Proximal End Articulation System 
       FIG. 21  is an enlarged isometric view of the handle  1614  of  FIGS. 16-17  depicting another example actuation system  2100 , according to one or more embodiments. The outer body of the handle  1614  is again shown in phantom to enable viewing of the internal mechanisms housed within the handle  1614 , including the actuation system  2100 . Various other actuation systems and component parts of the handle  1614  are omitted in  FIG. 21  for simplicity. 
     According to one or more embodiments, the actuation system  2100  may be operable (actuatable) to cause the end effector  1604  ( FIG. 16 ) to articulate at the wrist  1606  ( FIGS. 16-17 ). Accordingly, the actuation system  2100  may include or otherwise be operatively coupled to the fifth drive input  1620   e,  as briefly mentioned above. Rotation (actuation) of the fifth drive input  1620   e,  via operation of the fifth drive output  1718   e  ( FIG. 17 ), may cause the actuation system  2100  to operate, which results in articulation of the end effector  1604 . In other embodiments, however, the actuation system  2100  may be designed to carry out other functions (operations) of the surgical tool  1600  ( FIG. 16 ) or the end effector  1604 , such as causing the shaft  1602  to translate relative to the handle  1614 , opening or closing the jaws  1610 ,  1612  ( FIGS. 16-17 ) at the end effector  1604 , or causing the end effector  1604  to “fire,” without departing from the scope of this disclosure. 
     As illustrated, the actuation system  2100  includes a nut  2102  coupled to a lead screw  2104  extending from the fifth drive input  1620   e.  The lead screw  2104  may be coupled to or form part of the fifth drive input  1620   e  such that rotation of the fifth drive input  1620   e  correspondingly rotates the lead screw  2104  in the same direction. Moreover, the lead screw  2104  defines external helical threading  2106   a  matable with internal helical threading  2106   b  defined by the nut  2102 . Consequently, as the lead screw  2104  rotates, threaded engagement between the external and internal threading  2106   a,b  urges the nut  2102  to traverse the lead screw  2104  either proximally or distally, depending on the rotation direction of the lead screw  2104 . In some embodiments, the internal threading  2106   b  may be defined on the nut  2102 , but in other embodiments, the internal threading  2106   b  may be defined on a linear slide element (not shown) disposed within and coupled to the nut  2102 . 
     In some embodiments, the nut  2102  may provide or otherwise define one or more channel guides  2108  (two shown). The channel guides  2108  may be configured to receive opposing guide structures (not shown) provided by the handle  1614 . As the nut  2102  traverses the lead screw  2104 , the guide structures correspondingly traverse the channel guides  2108  and help prevent the nut  2102  from rotating as the lead screw  2104  rotates. 
     The nut  2102  may provide or otherwise include an armature  2110  extending laterally from the nut  2102  and toward the shaft  1602 . In some embodiments, a first or “upper” pulley  2112   a  may be rotatably mounted to the armature  2110 , such as at or near the end of the armature  2110 . A second or “lower” pulley  2112   b  may be rotatably coupled to the handle  1614  and axially offset from the upper pulley  2112   a.  Accordingly, movement of the nut  2102  along the lead screw  2104  will correspondingly move the upper pulley  2112   a  toward or away from the lower pulley  2112   b,  which remains stationary relative to the handle  1614  during operation. The pulleys  2112   a,b  may comprise double barrel pulleys (alternately referred to as “double pulleys”) capable of accommodating two drive members or drive cables. 
     The actuation system  2100  may further include a first drive member  2114   a  and a second drive member  2114   b  that extend longitudinally along at least a portion of the shaft  1602  and interact with the pulleys  2112   a,b.  In the illustrated embodiment, each drive member  2114   a,b  comprises a cable or wire and, therefore, will be referred to herein as “drive cables  2114   a,b ”. In other embodiments, however, the drive cables  2114   a,b  may comprise any of the other types of drive members mentioned herein. As illustrated, the drive cables  2114   a,b  may be received and extend within a groove  2116  defined in the shaft  1602 . In other embodiments, however, the drive cables  2114   a,b  may alternatively be received within the interior of the shaft  1602  or extend along an exterior surface of the shaft  1602 , without departing from the scope of the disclosure. 
     A first or “distal” end  2118   a  of each drive cable  2114  may be anchored to the shaft  1602  below (distal to) the handle  1614 , and a second or “proximal” end  2118   b  (see  FIGS. 22A-22B ) of each drive cable  2114  may be anchored to the shaft  1602  above (proximal to) the handle  1614 . As discussed in more detail below, the proximal end  2118   b  of each drive cable  2114  may be anchored at or near the proximal end  1902  ( FIGS. 22A-22B ) of the shaft  1602 . Accordingly, the drive cables  2114   a,b  may be anchored both proximally and distally along the shaft  1602 . 
     The actuation system  2100  may further include a first or “upper” idler pulley  2120   a  and a second or “lower” idler pulley  2120   b.  The upper and lower idler pulleys  2120   a,b  may each be rotatably coupled to the handle  1614  and longitudinally (axially, vertically, etc.) offset from each other. More specifically, in some embodiments, the upper idler pulley  2120   a  may be mounted within the handle  1614  at or above a proximal end  2122   a  of the external threading  2106   a,  and the lower idler pulley  2120   b  may be mounted within the handle  1614  at or below a distal end  2122   b  of the external threading  2106   a.  Consequently, movement of the nut  2102  along the lead screw  2104  may not be able to surpass the position of the idler pulleys  2120   a,b  on either end  2122   a,b  of the lead screw  2104 . 
     In some embodiments, the pulleys  2112   a,b  may have parallel axes of rotation. In some embodiments, the idler pulleys  2120   a,b  may also have parallel axes of rotation, but may alternatively have non-parallel axes of rotation. In some embodiments, the pulleys  2112   a,b  may be arranged for rotation in the same plane, while the idler pulleys  2120   a,b  may be arranged for rotation in a plane that is offset from the rotation plane of the pulleys  2112   a,b.  In at least one embodiment, the idler pulleys  2120   a,b  may be arranged for rotation in non-parallel planes, but nonetheless offset from the rotation plane of the pulleys  2112   a,b,  without departing from the scope of the disclosure. 
     As illustrated, the drive cables  2114   a,b  may be configured to extend or be threaded (guided) through the actuation system  2100  and, more particularly, through the pulleys  2112   a,b  and the idler pulleys  2120   a,b  within the body of the handle  1614 . The upper pulley  2112   a  may be arranged and otherwise configured to receive the first drive cable  2114   a  from a proximal portion of the shaft  1602  and redirect the first drive cable  2114   a  from the shaft  1602  to the upper idler pulley  2120   a.  The upper idler pulley  2120   a  may then redirect the first drive cable  2114   a  to the lower idler pulley  2120   b,  which may be arranged to redirect the first drive cable  2114   a  to the lower pulley  2112   b.  The lower pulley  2112   b  may be arranged to redirect the first drive cable  2114   a  back to the shaft  1602  (e.g., within the groove  2116 ) to extend distally. In contrast, the lower pulley  2112   b  may be arranged and otherwise configured to receive the second drive cable  2114   b  from the proximal portion of the shaft  1602  and redirect the second drive cable  2114   b  from the shaft  1602  to the upper pulley  2112   a.  The upper pulley  2112   a  may then be configured to redirect the second drive cable  2114   a  back to the shaft  1602  (e.g., within the groove  2116 ) to extend distally therefrom. 
     As mentioned above, the actuation system  2100  may be actuated or operated by rotating the fifth drive input  1620   e,  via operation of the fifth drive output  1718   e  ( FIG. 17 ). Rotating the fifth drive input  1620   e  in a first angular direction C (e.g., clockwise) will correspondingly rotate the lead screw  2104  in the same direction C and thereby cause the nut  2102  to move proximally along the lead screw  2104 , as indicated by the arrow D. Moving the nut  2102  proximally D simultaneously moves the upper pulley  2112   a  away from the lower pulley  2112   b.  In contrast, rotating the fifth drive input  1620   e  in a second angular direction E (e.g., counter-clockwise) opposite the first angular direction C will correspondingly rotate the lead screw  2104  in the same direction E and thereby cause the nut  2102  to move distally along the lead screw  2104 , as indicated by the arrow F. Moving the nut  2102  distally F simultaneously moves the upper pulley  2112   a  toward the lower pulley  2112   b.    
     Actuation or operation of the actuation system  2100  may result in antagonistic manipulation of the drive cables  2114   a,b  that results in articulation of the end effector  1604  ( FIG. 16 ) at the wrist  1606  ( FIGS. 16-17 ). More specifically, movement of the nut  2102  along the lead screw  2104  may result in the overall lengths of the drive cables  2114   a,b  changing equally and opposite by a factor of two times (2×) the motion of the nut  2102 . This is possible since the drive cables  2114   a,b  are each fixed at opposite ends to the shaft  1602  and guided through (nested within) the upper and lower pulleys  2112   a,b,  where the upper pulley  2112   a  is able to move toward or away from the lower pulley  2112   b  based on rotational direction of the lead screw  2104 . 
     In example operation, as the nut  2102  is actuated to move proximally D along the lead screw  2104  by one (1) unit of length, the actuation system  2100  will pay out (dispense) two (2) units of length of the first drive cable  2114   a  to the shaft  1602  and simultaneously pay in (draw in) two (2) units of length of the second drive cable  2114   b  from the shaft  1602 . In contrast, as the nut  2102  is actuated to move distally F along the lead screw  2104  by one (1) unit of length, the actuation system  2100  will pay in (draw in) two (2) units of length of the first drive cable  2114   a  from the shaft  1602  and simultaneously pay out (dispense) two (2) units of length of the second drive cable  2114   b  to the shaft  1602 . Such antagonistic and simultaneous operation of the drive cables  2114   a,b  helps to articulate the end effector  1604  ( FIG. 16 ) at the wrist  1606  ( FIGS. 16-17 ), as discussed below. 
     In some embodiments, the actuation system  2100  may be decoupled from shaft  1602  insertion. More specifically, the pulleys  2112   a - c  and the idler pulleys  2120   a,b  may be able to freely rotate (e.g., “free wheel”) and are otherwise not driven during operation of the handle  1614 . Consequently, as the shaft  1602  moves longitudinally relative to the handle  1614  in z-axis translation, the drive cables  2114   a,b  are able to freely run (course) through the actuation system  2100  and about the pulleys  2112   a - c  and the idler pulleys  2120   a,b.  Moreover, since the pulleys  2112   a - c  and the idler pulleys  2120   a,b  are able to freely rotate, the actuation system  2100  can be operated simultaneously during shaft  1602  z-axis translation. 
       FIG. 22A  is an enlarged, isometric side view of an example rocker bar system  2200 , according to one or more embodiments of the present disclosure. The rocker bar system  2200  may work in conjunction with the actuation system  2100  ( FIG. 21 ) to articulate the end effector  1604  ( FIG. 16 ) at the wrist  1606  ( FIGS. 16-17 ). More specifically, operation of the actuation system  2100  causes the rocker bar system  2200  to actuate and thereby articulate the end effector  1604 , as will be discussed below. 
     The rocker bar system  2200  may be arranged at or near the proximal end  1902  of the shaft  1602 . In the illustrated embodiment, for example, the rocker bar system  2200  may be mounted to the tail piece  1912 , which is coupled to the proximal end  1902  of the shaft  1602 . In at least one embodiment, however, the tail piece  1912  may form part of the rocker bar system  2200 . 
     The drive cables  2114   a,b  extend from the handle  1614  ( FIG. 21 ) to the rocker bar system  2200 , and the proximal ends  2118   b  of the drive cables  2114   a,b  may be secured (anchored) to the shaft  1602  at or near its proximal end  1902 . In at least one embodiment, for example, the proximal ends  2118   b  of the drive cables  2114   a,b  may be secured to the tail piece  1912 . The rocker bar system  2200  may further include a rocker bar  2202  pivotably mounted to the shaft  1602  and/or the tail piece  1912 , and the rocker bar  2202  may be configured to receive and redirect the drive cables  2114   a,b  at the proximal end  1902  of the shaft  1602 . 
     The rocker bar system  2200  may further include various pulleys used to receive and redirect the drive cables  2114   a,b.  In the illustrated embodiment, for example, a first rocker pulley  2204   a  may be rotatably mounted to a first lateral arm  2206   a  of the rocker bar  2202 , and a second rocker pulley  2204   b  may be rotatably mounted to a second lateral arm  2206   b  of the rocker bar  2202 . In at least one embodiment, as illustrated, the lateral arms  2206   a,b  may extend laterally outward past opposing sides of the shaft  1602 . As will be appreciated, a mechanical advantage can be gained with the lateral arms  2206   a,b  extending outward from the pivot point of the rocker bar  2202 . The further out the lateral arms  2206   a,b  extend, the greater the mechanical advantage achieved. Additional mechanical advantage is also obtained by double-wrapping the drive cables  2114   a,b  around the rocker pulleys  2204   a,b.  More specifically, if the drive cables  2114   a,b  terminated at the end of the rocker bar  2202 , then there would be no amplification. Routing the drive cables  2114   a,b  around the rocker pulleys  2204   a,b  provides a 2:1 block-tackle amplification on top of the lever arm advantage. 
     In some embodiments, the rocker bar system  2200  may further include first and second redirection pulleys  2208   a  and  2208   b  rotatably mounted to the shaft  1602 . In at least one embodiment, as illustrated, the redirection pulleys  2208   a,b  may be rotatably mounted to the tail piece  1912 , which is coupled to the shaft  1602 . The first rocker pulley  2204   a  may be configured to receive the first drive cable  2114   a  from the first redirection pulley  2208   a,  and the second rocker pulley  2204   b  may receive the second drive cable  2114   b  from the second redirection pulley  2208   b.  In at least one embodiment, however, one or both of the redirection pulleys  2208   a,b  may be omitted from the rocker bar system  2200  and the drive cables  2114   a,b  may instead be fed directly to the first and second rocker pulleys  2204   a,b,  respectively, without departing from the scope of the disclosure. 
       FIG. 22B  is another enlarged, isometric side view of the rocker bar system  2200 , according to one or more embodiments. In  FIG. 22B , the tail piece  1912  ( FIG. 22A ) and a portion of the shaft  1602  are omitted to enable viewing of various component parts of the rocker bar system  2200 . As discussed above, the first drive cable  2114   a  may be received by the first redirection pulley  2208   a,  which redirects the first drive cable  2114   a  to the first rocker pulley  2204   a,  and the second drive cable  2114   b  may be received by the second redirection pulley  2208   b,  which redirects the second drive cable  2114   b  to the second rocker pulley  2204   b.    
     In some embodiments, one or more additional pulleys (not shown) may be arranged between the redirection pulleys  2208   a,b  and the rocker pulleys  2204   a,b,  respectively. The additional pulleys may prove advantageous in creating an arc path for the cables  2114   a,b,  instead of following a straight line. The arc path(s) may be dimensioned to ensure a length conservative mechanism in the tail piece  1912  ( FIG. 22A ) that matches the cable management within the handle  1614  ( FIG. 21 ). Alternatively, or in addition thereto, the lateral arms  2206   a,b  of the rocker bar  2202  may comprise rocker wheels (or half wheels), with respective cables  2114   a,b  running from opposite points on the diameter, around the arc of the rocker wheel down and to the corresponding redirection pulleys  2208   a,b.    
     In some embodiments, as illustrated, the proximal ends  2118   b  of the drive cables  2114   a,b  may be coupled to each other, such as with a crimp  2210  or the like. In such embodiments, the crimp  2210  may be secured to the shaft  1602  and/or the tail piece  1912  ( FIG. 21 ), thus anchoring the drive cables  2114   a,b  to the shaft  1602  at the proximal end  1902 . In other embodiments, however, the proximal ends  2118   b  of the drive cables  2114   a,b  may alternatively be anchored and otherwise terminate at the lateral arms  2206   a,b  of the rocker bar  2202 , without departing from the scope of the disclosure. 
     The cable management system  2200  may further include first and second drive rods  2212   a  and  2212   b  that extend longitudinally along the shaft  1602 . The first drive rod  2212   a  may be pivotably coupled to the first lateral arm  2206   a  and the second drive rod  2212   b  may be pivotably coupled to the second lateral arm  2206   b.  The drive rods  2212   a,b  (alternately referred to as “articulation rods”) may extend distally to the wrist  1606  ( FIG. 16 ) where they may be operatively coupled to the wrist  1606  such that antagonistic longitudinal movement of the drive rods  2212   a,b  may cause the end effector ( FIGS. 16-17 ) to articulate at the wrist  1606 . 
     In some embodiments, as illustrated, the rocker bar  2202  may be rotatably mounted to a yoke  2214 . The yoke  2214  may be secured to the proximal end  1902  of the shaft  1602  or may alternatively form an integral part thereof. The yoke  2214  may provide or define a pin  2216  and the rocker bar  2202  may be pivotably mounted to the yoke  2214  at the pin  2216 . Accordingly, the rocker bar  2202  may be considered pivotably mounted to the proximal end  1902  of the shaft  1602 . 
     Depending on the tension or tensile loading provided in the drive cables  2114   a,b,  the rocker bar  2202  may be urged to pivot about the pin  2216  in either a first angular direction, as indicated by the arrow G, or a second angular direction, as indicated by the arrow H, and opposite the first angular direction G. More specifically, operation of the actuation system  2100  ( FIG. 21 ) in a first direction or mode (e.g., distal movement of the nut  2102  of  FIG. 21 ) may apply tension on the first drive cable  2114   a  while simultaneously slackening the second drive cable  2114   b.  Such antagonistic operation of the drive cables  2114   a,b  may urge the rocker bar  2202  to pivot in the first angular direction G, which correspondingly moves (pushes) the first drive rod  2212   a  distally, as indicated by the arrow I, and simultaneously moves (pulls) the second drive rod  2212   b  proximally, as indicated by the arrow J. In contrast, operation of the actuation  2100  system in a second direction or mode (e.g., proximal movement of the nut  2102  of  FIG. 21 ) may apply tension on the second drive cable  2114   b  while simultaneously slackening the first drive cable  2114 . This may urge the rocker bar  2202  to pivot in the second angular direction H and correspondingly move (push) the second drive rod  2212   b  distally I and simultaneously move (pull) the first drive rod  2212   a  proximally J. Such antagonistic movement of the drive rods  2212   a,b  may cause the end effector ( FIGS. 16-17 ) to articulate at the wrist  1606  ( FIG. 16 ). 
     Referring now to  FIG. 23 , with continued reference to  FIGS. 22A-22B , depicted is an enlarged isometric view of the end effector  1604  and an exposed view of a portion of the wrist  1606 , according to one or more embodiments. In  FIG. 23 , the body of the shaft  1602  has been removed to enable viewing of how the drive rods  2212   a,b  interconnect with or are otherwise operatively connected to the end effector  1604 . In the illustrated embodiment, the end effector  1604  is mounted to an end effector mount  2302  that defines or otherwise provides two articulation pins  2304 , and the distal end of each drive rod  2212   a,b  is rotatably mounted to a corresponding one of the articulation pins  2304 . The drive rods  2212   a,b  are also interconnected at the distal ends via a distal link  2306 , which together comprise a linkage configured to help articulate end effector mount  2302 , and therefore the end effector  1604 , in a plane parallel to the longitudinal axis A 1 . 
     In this configuration, the drive rods  2212   a,b  translate antagonistically and parallel along the longitudinal axis A 1 , such that as the first drive rod  2212   a  moves distally the second drive rod  2212   b  moves proximally, and vice versa, as generally discussed above. Moreover, distal movement of the first drive rod  2212   a  and simultaneous proximal movement of the second drive rod  2212   b  cooperatively act on the end effector mount  2302  to cause the end effector  1604  to rotate counter-clockwise, as indicated by the arrow K 1 . In contrast, proximal movement of the first drive rod  2212   a  and simultaneous distal movement of the second drive rod  2212   b  cooperatively act on the end effector mount  2302  to cause the end effector  1604  to rotate clockwise, as indicated by the arrow K 2 . 
     3. Implementing Systems and Terminology. 
     Implementations disclosed herein provide systems, methods and apparatus for instruments for use with robotic systems. It should be noted that the terms “couple,” “coupling,” “coupled” or other variations of the word couple as used herein may indicate either an indirect connection or a direct connection. For example, if a first component is “coupled” to a second component, the first component may be either indirectly connected to the second component via another component or directly connected to the second component. 
     The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. 
     As used herein, the term “plurality” denotes two or more. For example, a plurality of components indicates two or more components. The term “determining” encompasses a wide variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” can include resolving, selecting, choosing, establishing and the like. 
     The phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” describes both “based only on” and “based at least on.” 
     As used herein, the terms “generally” and “substantially” are intended to encompass structural or numeral modification which do not significantly affect the purpose of the element or number modified by such term. 
     To aid the Patent Office and any readers of this application and any resulting patent in interpreting the claims appended herein, applicants do not intend any of the appended claims or claim elements to invoke 35 U.S.C. 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim. 
     The foregoing previous description of the disclosed implementations is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these implementations will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the scope of the invention. For example, it will be appreciated that one of ordinary skill in the art will be able to employ a number corresponding alternative and equivalent structural details, such as equivalent ways of fastening, mounting, coupling, or engaging tool components, equivalent mechanisms for producing particular actuation motions, and equivalent mechanisms for delivering electrical energy. Thus, the present invention is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.