Patent Publication Number: US-2020289225-A1

Title: Modular device comprising mechanical arms

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/454,116 filed on Mar. 9, 2017, which claims the benefit of priority under 35 USC § 119(e) of U.S. Provisional Patent Application No. 62/305,631 filed on Mar. 9, 2016, and which also is Continuation-in-Part (CIP) of U.S. patent application Ser. No. 15/501,862 filed on Feb. 6, 2017, which is a National Phase of PCT Patent Application No. PCT/IL2016/050976 having International filing date of Sep. 4, 2016, which claims the benefit of priority under 35 USC § 119(e) of U.S. Provisional Patent Application No. 62/305,613 filed on Mar. 9, 2016. 
     This application is also related to PCT Patent Application Nos. PCT/IL2015/050891, PCT/IL2015/050892, and PCT/IL2015/050893, all having International filing date of Sep. 4, 2015. 
     The contents of the above applications are all incorporated by reference as if fully set forth herein in their entirety. 
    
    
     FIELD AND BACKGROUND OF THE INVENTION 
     The present invention, in some embodiments thereof, relates to actuation of a device including at least one surgical arm and, more particularly, but not exclusively, to a motor unit configured for actuating at least one surgical arm. 
     Background art includes: “Design of a Compact Robotic Manipulator for Single-Port Laparoscopy” by Claudio Quaglia et al, Paper No: MD-13-1148 in J. Mech. Des. 136(9), 095001 (Jun. 13, 2014); “An inverse kinematics method for 3D FIGs. with motion data” by Taku Komura et al, Proceedings of the Computer Graphics International (CGI&#39; 03);
     Hubens et al., 2004, “What Have we Learnt after Two Years Working with the Da Vinci Robot System in Digestive Surgery?”, Acta chir belg;   Michael Irvine, 2009, “Anaesthesia for Robot-Assisted Laparoscopic Surgery”, Cont Edu Anaesth Crit Care and Pain;   Jeong Rim Lee, 2014, “Anesthetic considerations for robotic surgery”, Korean Journal of Anesthesiology;   Teljeur et al., 2014, “Economic evaluation of robot-assisted hysterectomy: a cost-minimisation analysis”, BJOG;   Box et al., 2008, “Rapid communication: robot-assisted NOTES nephrectomy: initial report”, J Endourol;   D R. Domigo, 2009, “Overview of current hysterectomy trends”, Expert Review of Obstetrics &amp; Gynecology; and   D R. Kho, “Vaginal versus laparoscopic hysterectomy”, Contemporary OB/GYN Expert Advice, 2013.   

     Additional background art includes U.S. Pat. Nos. 8,224,485, 8,347,754, 7,833,156, 8,518,024, International Patent Application Publication No. WO 2010096580, and International Patent Application Publication No. WO 2013116869. 
     SUMMARY OF THE INVENTION 
     According to an aspect of some embodiments of the present invention there is provided a surgical system comprising: 
     at least two modular units, the modular units each comprising:
         a surgical arm; and   a motor unit configured for actuating movement of the surgical arm, the motor unit configured to be operably attached to the surgical arm, where a first face of a motor unit housing generally defines a plane which is at an angle of 60-120° to a long axis of the surgical arm;   wherein the motor unit is configured to be aligned adjacent a motor unit of at least one second modular unit;   wherein a second face of a housing of the motor unit generally defines a plane which is at an angle to the first face and which comprises a connection geometry suitable for connecting the housing of the motor unit to a housing of the motor unit of the second modular unit.       

     According to some embodiments of the invention, the motor unit is configured to be operably attached to the surgical arm such that the surgical arm extends from the first face of the motor unit housing. 
     According to some embodiments of the invention, the second face is 60-120° to the first face. 
     According to some embodiments of the invention, the motor unit housing has an elongated shape, wherein the second face is a longitudinal face of the motor unit housing. 
     According to some embodiments of the invention, a central long axis of the motor unit is parallel to a central long axis of at least a portion of the surgical arm extending from the motor unit, the motor unit comprising a proximal extension of the surgical arm. 
     According to some embodiments of the invention, the connection geometry is configured such that when the modular unit is connected to the second modular unit a separation between the second face of the modular unit housing and second face of the second modular unit housing is less than 2 mm. 
     According to some embodiments of the invention, the connection geometry is configured such that when the modular unit is connected to the second modular unit the second face of the modular unit housing directly contacts a second face of the second modular unit housing. 
     According to some embodiments of the invention, the modular unit is attached to the second modular unit at the connection geometry, a distance between long axes of the surgical arms adjacent to the motor unit housings is less than 5 mm. 
     According to some embodiments of the invention, the system includes a plurality of the modular units. 
     According to some embodiments of the invention, the connection geometry comprises one or both of protrusions and indentations for engaging respective indentations and protrusions of the housing of the motor unit of the second modular unit. 
     According to some embodiments of the invention, the connection geometry comprises one or both of protrusions and indentations for engaging respective indentations and protrusions of one or more connector. 
     According to some embodiments of the invention, the protrusions and indentions extend in a substantially perpendicular direction relative to the second face of the housing. 
     According to some embodiments of the invention, the surgical arm is positioned at a lateral distance smaller than 1 mm from the second face of the housing. 
     According to some embodiments of the invention, modular units are each configured to operate independently. 
     According to some embodiments of the invention, the second face is a portion of the motor unit housing where 90-99% of a surface are of a portion of the housing varies by at most 0.1-1 mm from a planar tangent. 
     According to some embodiments of the invention, at least one of the motor units comprises an integral linear unit, the linear unit configured for actuating at least one of advancement and retraction of the modular unit. 
     According to some embodiments of the invention, at least one of the motors unit is configured to be coupled to a linear unit, the linear unit configured for actuating at least one of advancement and retraction of the modular unit. 
     According to some embodiments of the invention, the linear unit comprises: 
     an elongated rail comprising a proximal end and a distal end; 
     a sliding element positionable on the rail, the sliding element couplable to the motor unit; the sliding element configured to move proximally and distally on the rail to move the motor unit. 
     According to some embodiments of the invention, the system comprises a plurality of modular units and wherein a single linear unit is configured to actuate linear movement of the plurality of modular units. 
     According to some embodiments of the invention, the system comprising two modular units, wherein motor units of the two modular units, attached at the connection geometries and additionally interlocked to each other. 
     According to some embodiments of the invention, at least a third face of the housing comprises a connection geometry suitable for engaging a face of an additional modular unit. 
     According to some embodiments of the invention, at least a third longitudinal face of the housing comprises a connection geometry suitable for engaging a face of an additional modular unit. 
     According to some embodiments of the invention, each longitudinal face of the housing comprises a connection geometry suitable for engaging a longitudinal face of an additional modular unit. 
     According to some embodiments of the invention, a coupling between the motor units comprises a quick release mechanism comprising a latch configured to release a lock of the motor units. 
     According to some embodiments of the invention, the motor unit is configured for actuating one or both of rotation and bending of at least a portion of the surgical arm. 
     According to some embodiments of the invention, the system further comprises a third arm. 
     According to some embodiments of the invention, the system comprises three modular units, a third modular unit comprising a third motor unit and the third arm. 
     According to some embodiments of the invention, the third arm carries a camera. 
     According to some embodiments of the invention, the linear unit comprises a sensor for detecting if the unit is connected to an external device or system. 
     According to some embodiments of the invention, the modular unit comprises a sensor for detecting if the modular unit is connected to an additional unit or units. 
     According to an aspect of some embodiments of the present invention there is provided a method of constructing a system comprising one or more surgical arms, comprising: 
     providing:
         a plurality of modular units, each modular unit comprising at least one surgical arm attached to at least one motor unit configured for actuating movement of the surgical arm;   coupling one or more modular units to each other in an attachment configuration;   displaying on a user interface one or both of an indication of the attachment configuration and a selection of an attachment configuration.       

     According to some embodiments of the invention, the method comprises selecting a surgical approach using the user interface. 
     According to some embodiments of the invention, the coupling is in accordance with the selected surgical approach. 
     According to some embodiments of the invention, the coupling is performed during one or both of: set-up of the system prior to the surgery, and during the surgery. 
     According to some embodiments of the invention, the selecting a surgical approach comprises deciding a number of surgical ports for accessing a patient&#39;s body. 
     According to some embodiments of the invention, the selecting a surgical approach comprises deciding a location on a patient&#39;s body for each port for accessing a patient&#39;s body. 
     According to some embodiments of the invention, a number of the modular units is selected in accordance with the number of surgical ports through which the surgery is performed. 
     According to some embodiments of the invention, a spatial arrangement of modular units is selected in accordance with a number of surgical ports through which the surgery is performed. 
     According to some embodiments of the invention, a number of surgical arms is selected in accordance with a number of surgical ports through which the surgery is performed. 
     According to some embodiments of the invention, a port comprises a natural body orifice or an incised opening. 
     According to some embodiments of the invention, the natural body orifice is a vagina. 
     According to some embodiments of the invention, the method comprises introducing one or more surgical arms through the ports. 
     According to some embodiments of the invention, the method comprises introducing two surgical arms through the ports. 
     According to some embodiments of the invention, the method comprises introducing two surgical arms through a single port. 
     According to some embodiments of the invention, the method comprises comprising modifying an architecture of the system in real time by coupling or decoupling modular units. 
     According to an aspect of some embodiments of the present invention there is provided a surgical system comprising: 
     a plurality of surgical arms, 
     a plurality of motor units, each motor unit configured for actuating movement of a surgical arm, where at least two of the plurality of motor units are each configured to attach to another motor unit; and 
     a memory configured to store a model of an attachment configuration of the plurality of motor units. 
     According to some embodiments of the invention, the system comprises a processor connected to the memory. 
     According to some embodiments of the invention, the system comprises a user interface through which a user inputs a selected attachment configuration of the plurality of motor units, wherein the user interface is connected to the processor. 
     According to some embodiments of the invention, the selected attachment configuration is received by the processor and stored in the memory. 
     According to some embodiments of the invention, the memory stores a plurality of possible attachment configurations and the user selects, through the user interface, one of the plurality of attachment configurations. 
     According to some embodiments of the invention, the system comprises at least one sensor configured to detect attachment of a motor unit to another motor unit and to send a signal indicating attachment or lack thereof to the processor, wherein the processor derives an attachment configuration from the signal. 
     According to some embodiments of the invention, the system comprises a user interface; 
     wherein the processor is configured to instruct the user interface to display an indication of the attachment configuration of the plurality of motor units. 
     According to an aspect of some embodiments of the present invention there is provided a method of constructing a system comprising one or more surgical arms, comprising: 
     providing:
         a plurality of modular units, each modular unit comprising at least one surgical arm attached to at least one motor unit configured for actuating movement of the surgical arm;   selecting a surgical approach; and   coupling one or more modular units to each other in an attachment configuration in accordance with the selected surgical approach.       

     According to an aspect of some embodiments of the present invention there is provided a surgical system comprising: 
     a first separably operable modular motor unit; 
     a second separably operable modular motor unit configured to attach to the first modular motor unit; 
     two modular surgical mechanical arms, each arm configured to attach to and be actuated by at least one of the motor units; 
     an input system; 
     a controller configured to receive measured movement from the input system and to send a control signal based on the measured movement of the input system to the motor units. 
     According to some embodiments of the invention the input system includes a first input device arm and a second input device arm; 
     wherein the controller is configured to receive measured movement of the input device arms and to send:
         a first control signal based on the measured movement of the first input device arm to the first motor unit; and   a second control signal based on measured movement of the second input device arm to the second motor unit.       

     According to an aspect of some embodiments of the present invention there is provided a modular motor unit configured to actuate an elongate surgical arm comprising a plurality of coaxial surgical arm gears, the modular motor unit comprising: 
     a motor unit housing; 
     a plurality of motor gears disposed within the housing, each motor gear configured to actuate a surgical arm gear disposed within the housing, where surgical arm gears are coaxial with each other and are coaxial with a long axis of the surgical arm; 
     wherein the motor gears are sized and positioned such that the long axis of the surgical arm extends from the housing a small distance from a face of the housing. 
     According to an aspect of some embodiments of the present invention there is provided a surgical system comprising: 
     a plurality of modular units, each modular unit comprising:
         a surgical arm;   a motor unit configured to attach to and actuate the surgical arm; and   a motor unit housing including a plurality of faces, where more than one face includes at least one connection geometry configured to connect the motor unit housing to a housing of another motor unit.       

     According to some embodiments of the invention the motor unit housing has rotational symmetry. 
     According to an aspect of some embodiments of the present invention there is provided a surgical system comprising: 
     a plurality of surgical arms; 
     a plurality of separably operable motor units, each motor unit configured to attach to and actuate at least one of the surgical arms; 
     a plurality of modular user interfaces, each user interface configured to generate an input signal; 
     a controller configured to receive the input signals and configured to generate a control signal based on each input signal and send the each control signal to a different motor unit; 
     wherein one or more of the motor units is configured to attach to at least another of the motor units. 
     According to an aspect of some embodiments of the present invention there is provided a system comprising: 
     at least one surgical arm, the arm comprising at least one movable joint; 
     a motor unit configured for actuating movement of the surgical arm, the motor unit comprising a linear extension of the surgical arm; and 
     wherein a portion of the extension configured between the motor unit and the at least one moveable joint comprises a mechanically fixed curvature. 
     According to some embodiments of the invention the portion of the extension comprises a flexible shaft segment overlaid by a more rigid over tube. 
     According to some embodiments of the invention a proximal end of the over tube is fixedly attached to the motor unit. 
     According to some embodiments of the invention the system comprises two surgical arms, wherein at least one of the arms is curved such that the arms converge towards each other or diverge away from each other. 
     According to some embodiments of the invention the system comprises a third arm. 
     According to some embodiments of the invention the arm carries a camera. 
     According to an aspect of some embodiments of the present invention there is provided a unit for actuating linear movement of a system comprising one more surgical arms, comprising: 
     an elongated rail comprising a proximal end and a distal end; 
     a sliding element positionable on the rail, the sliding element couplable to a motor unit of the system; the sliding element configured to move proximally and distally on the rail to move the motor unit. 
     According to some embodiments of the invention linear movement of the system on the rail is actuated by a motor configured in the motor unit. 
     According to some embodiments of the invention the motor comprises a brake. 
     According to some embodiments of the invention the unit comprises a sensor for detecting if the unit was connected to an external device or system. 
     According to an aspect of some embodiments of the present invention there is provided a surgical system comprising: 
     two surgical arm; 
     a motor construct comprising two motor units arranged side by side, each motor unit configure for actuating movement of one of the surgical arms; 
     wherein each surgical arm extends distally from its respective motor unit; and 
     wherein the motor units are aligned with respect to each other on opposing sides of central long axis of the motor construct, holding the surgical arms at lateral distance of less than 5 mm between the arms. 
     According to an aspect of some embodiments of the invention, there is provided a modular unit comprising: 
     a surgical mechanical arm; 
     an elongate motor unit comprising: one or more actuating elements configured to actuate the arm and an elongate recess sized and shaped to receive a portion of the surgical arm such that the actuating elements contact the surgical arm. 
     According to some embodiments of the invention the one or more actuating element is a gear driven by a motor;
         wherein the surgical mechanical arm comprises one or more arm gear rotation of which results in movement of a portion of the surgical arm;   wherein, when the arm is within the recess, the gear contacts the arm gear.       

     According to some embodiments of the invention the surgical mechanical arm includes a plurality of gears and the motor unit includes a plurality of gears configured to actuate the arm gears, when the arm is within the recess. 
     According to some embodiments of the invention a long axis of the recess is at an angle of less than 20° of a long axis of the motor unit. 
     According to some embodiments of the invention the motor unit is activated by insertion of a portion of the surgical arm into the recess. 
     According to an aspect of some embodiments of the invention, there is provided a method of controlling movement of a surgical mechanical arm comprising:
         moving including one or more of bending and rotating portions of the surgical mechanical arm using a motor unit coupled to the surgical mechanical arm;   linearly moving the surgical arm using a linear unit coupled to the arm.       

     According to some embodiments of the invention the linear unit is coupled to the motor unit. 
     According to some embodiments of the invention the linear unit is an integral part of the motor unit. 
     According to some embodiments of the invention the linearly moving includes linearly advancing and retracting the surgical arm. 
     According to some embodiments of the invention the linearly moving includes linearly moving the surgical arm by linearly moving the motor unit. 
     According to an aspect of some embodiments of the invention, there is provided a surgical system comprising: a surgical device sized and shaped for insertion into a human body comprising: at least one surgical device articulated limb, which limb comprises: a support portion; a separably bendable first flexible portion coupled to the support portion; a second flexible portion, separably bendable of the first flexible portion, coupled to the first flexible portion; and at least one actuator configured to bend the first and the second flexible portions, an input device, comprising at least one input device articulated limb, which input device limb comprises: a support segment; a first segment coupled to the support segment by a first joint; a second segment coupled to the first segment by a second joint; and at least one sensor configured to measure a first input device angle between the first segment and the support segment and measures a second input device angle between the first segment and the second segment; and a controller configured to: receive a signal from the at least one sensor; send at least one control signal instructing the at least one actuator to: bend the first flexible portion, based on the first input device angle; and bend the second flexible portion, based the second input device angle. 
     In some embodiments, the control signal instructs the actuator: to bend the first flexible portion such that an surgical device first angle measured between a surgical device effective first segment and a surgical device support segment corresponds to the first input device angle; and to bend the second flexible portion such that an surgical device second angle measured between the surgical device effective first segment and a surgical device effective second segment corresponds to the second input device angle; wherein the surgical device first effective segment is a straight line connecting a long axis center point of the first flexible portion to a long axis midpoint of the second flexible portion; wherein the surgical device second effective segment is a straight line connecting a long axis midpoint of the second flexible portion to a distal end of the second flexible portion. 
     In some embodiments, the at least one sensor is configured to measure an orientation of the first segment with respect to the second segment and an orientation of the first segment with respect to the support segment; wherein the at least one actuator is configured to rotate the first flexible portion about a first flexible portion long axis and to rotate the second flexible portion about a second flexible portion long axis; wherein the control signal instructs the actuator: to rotate the first flexible portion based on the measured orientation of the first segment with respect to the second segment; and to rotate the second flexible portion based on the measured orientation of the second segment with respect to the first segment. 
     In some embodiments, the at least one sensor is a motion sensor attached to the articulated limb. In some embodiments, the at least one sensor is a magnetic differential encoder. In some embodiments, the at least one sensor comprises: a first sensor configured to measure the first input device angle; and a second sensor configured to measure the second input device angle. In some embodiments, the first sensor is configured to measure the orientation of the first segment with respect to the second segment; wherein the second sensor is configured to measure orientation of the second segment with respect to the first segment. In some embodiments, the at least one sensor comprises: a third sensor configured to measure the orientation of the first segment with respect to the second segment; and a fourth sensor configured to measure orientation of the second segment with respect to the first segment. 
     In some embodiments, the first flexible portion is bendable in a first flexible portion single bending plane; wherein the second flexible portion is bendable in a second flexible portion single bending plane. 
     In some embodiments, the first segment is bendable with respect to the support segment in a first joint single bending plane about the first joint; wherein the second segment is bendable with respect to the first segment in a second joint single bending plane about the second joint. In some embodiments, the first joint and the second joint are pivot joints. In some embodiments, the surgical device comprises a tool coupled to the second flexible portion. In some embodiments, actuation of the tool is controlled by one or more user interface on the input device. 
     In some embodiments, a ratio between a long axis length of the first segment to a long axis length of the second segment is about a ratio between a length of the first effective segment to a length of a second effective segment. In some embodiments, an effective long axis length of the first segment is about 10-30% longer than an effective long axis length of the second segment. 
     In some embodiments, the system comprises a first and a second input device limb and a first and second surgical device limb, wherein the first input device limb controls the first surgical device limb, according to claim  1  and wherein the second input device limb controls the second surgical device limb, according to claim  1 . 
     In some embodiments, a ratio of a first portion effective length to a first segment length is between 3:1 and 1:1 and a ratio of a second portion effective length to a second segment length is between 3:1 and 1:1. 
     In some embodiments, the coupling of the input device first segment, second segment and support segment is low enough friction such that moving a portion of the input device causes movement of portions coupled to the portion which are not individually restrained. 
     In some embodiments, the surgical device does not include motion sensors. 
     In some embodiments, the controller does not receive feedback from the surgical device. 
     As will be appreciated by one skilled in the art, some embodiments of the present invention may be embodied as a system, method or computer program product. 
     Accordingly, some embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, some embodiments of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. Implementation of the method and/or system of some embodiments of the invention can involve performing and/or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of some embodiments of the method and/or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware and/or by a combination thereof, e.g., using an operating system. 
     For example, hardware for performing selected tasks according to some embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to some embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to some exemplary embodiments of method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well. 
     Any combination of one or more computer readable medium(s) may be utilized for some embodiments of the invention. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
     A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
     Program code embodied on a computer readable medium and/or data used thereby may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
     Computer program code for carrying out operations for some embodiments of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
     Some embodiments of the present invention may be described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     Some of the methods described herein are generally designed only for use by a computer, and may not be feasible or practical for performing purely manually, by a human expert. A human expert who wanted to manually perform similar tasks, such as selecting an attachment configuration based on a selected surgical approach, might be expected to use completely different methods, e.g., making use of expert knowledge and/or the pattern recognition capabilities of the human brain, which would be vastly more efficient than manually going through the steps of the methods described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced. 
       In the drawings: 
         FIG. 1A  is a simplified schematic side view of a surgical device including a plurality of arms, according to some embodiments of the invention; 
         FIG. 1B  is a simplified schematic of a device including a plurality of arms, according to some embodiments of the invention; 
         FIGS. 1C-1D  are simplified schematic side views of surgical arms, according to some embodiments of the invention; 
         FIG. 2A  is a simplified schematic of a device, held by a support, according to some embodiments of the invention; 
         FIGS. 2B-2C  illustrate actuation of a device by a linear unit, according to some embodiments of the invention; 
         FIGS. 3A-3B  are simplified schematic views of a system where a device is held by a support, according to some embodiments of the invention; 
         FIG. 4A  is a simplified schematic cross sectional view of an arm with nested segment extensions, according to some embodiments of the invention; 
         FIG. 4B  is a simplified schematic of a side view of a portion of an arm, according to some embodiments of the invention; 
         FIG. 4C  is a simplified schematic cross sectional view of an arm with nested segment extensions, according to some embodiments of the invention; 
         FIG. 5A  is a flowchart of a method of constructing a modular system in accordance with a surgical approach, according to some embodiments of the invention; 
         FIG. 5B  illustrates exemplary surgical approaches, according to some embodiments of the invention; 
         FIG. 5C  is a schematic diagram of actuation of a surgical arm, according to some embodiments of the invention; 
         FIGS. 6A-6D  are various views of a motor construct for actuating a surgical arm, according to some embodiments of the invention; 
         FIGS. 7A-7D  are diagrams of various configurations of systems comprising different combinations of modular units, according to some embodiments of the invention; 
         FIGS. 8A-8B  illustrate an exemplary configuration including two modular units, according to some embodiments of the invention; 
         FIGS. 9A-9B  illustrate an exemplary configuration of a system including two separated modular units, according to some embodiments of the invention; 
         FIGS. 10A-10C  are exemplary mechanical arm layouts, according to some embodiments of the invention; 
         FIGS. 11A-11B  are a simplified schematic side view of a device  1100  including 3 arms, according to some embodiments of the invention; 
         FIGS. 12A-12E  schematically illustrate different approaches for using one or more mechanical arms in a multi-port surgery, according to some embodiments of the invention; 
         FIG. 13  illustrates use of two systems in a multi-port surgery, according to some embodiments of the invention; 
         FIGS. 14A-14D  illustrate a coupling between two motor units, according to some embodiments of the invention; 
         FIGS. 15A-15E  are cross section views of various arrangements of a coupling between gears of the motor unit and a surgical arm, and a coupling between a motor construct (e.g. comprising more than one motor unit) and a plurality of surgical arms, according to some embodiments of the invention; 
         FIG. 16A  is a simplified schematic of a surgical arm including surgical arm gears and a housing of a motor unit, according to some embodiments of the invention; 
         FIG. 16B  is a simplified schematic top view of a motor unit where a motor unit housing includes a plurality of anchors, according to some embodiments of the invention; 
         FIG. 17  is a simplified schematic top view of a motor unit connector, according to some embodiments of the invention; 
         FIG. 18  is a flow chart of a method of connecting a plurality of motor unit housings, according to some embodiments of the invention; 
         FIG. 19  is a flowchart of a method of connecting a plurality of motor unit housings, according to some embodiments of the invention; 
         FIG. 20A  is a simplified schematic exploded view of a plurality of motor units, associated surgical arms and a plurality of connectors prior to connection, according to some embodiments of the invention; 
         FIG. 20B  is a simplified schematic top view of a motor construct including a plurality of motor units connected by connectors in a square configuration, according to some embodiments of the invention; 
         FIG. 21  is a simplified schematic of a plurality of motor units connected in an elongated configuration, according to some embodiments of the invention; 
         FIG. 22A  is a simplified schematic of a plurality of connected motor units, and associated surgical arms, where one of the motor units has a different axial position, according to some embodiments of the invention; 
         FIG. 22B  is an enlarged view of the portion of the motor units illustrated in  FIG. 22A , according to some embodiments of the invention; 
         FIG. 23  is a simplified schematic of system including a first plurality of surgical arms inserted into a first port and a second plurality of surgical arms inserted into a second port, according to some embodiments of the invention; 
         FIG. 24A  is a simplified schematic side view of an input device arm, according to some embodiments of the invention; 
         FIG. 24B  is a simplified schematic side view of a surgical device arm, according to some embodiments of the invention; 
         FIG. 24C  is a simplified schematic side view of an input device arm, according to some embodiments of the invention; 
         FIG. 24D  is a simplified schematic side view of an input device arm, according to some embodiments of the invention; 
         FIG. 24E  is a simplified schematic side view of an input device arm, according to some embodiments of the invention; 
         FIG. 25  is a simplified schematic of arm gears A 1 - 6  and motor gears within a motor unit housing, according to some embodiments of the invention; 
         FIG. 26  is a simplified schematic of arm gears and motor gears within a motor unit housing, according to some embodiments of the invention; 
         FIG. 27  is a simplified schematic of a first and a second surgical arm, each arm including surgical arm gears, according to some embodiments of the invention; 
         FIG. 28A  is a simplified schematic of a system including two separate modular units configured to be attached to each other, according to some embodiments of the invention; 
         FIG. 28B  is a simplified schematic cross section of a motor construct, showing attachment between motor units, according to some embodiments of the invention; 
         FIG. 28C  is an enlarged view of the attachment of  FIG. 28B , according to some embodiments of the invention; 
         FIG. 28D  is a simplified schematic of a slide attachment, according to some embodiments of the invention; 
         FIG. 28E  is a simplified schematic of a plurality of modular surgical arms, according to some embodiments of the invention; 
         FIG. 29  is a simplified schematic side view of an actuation mechanism for control of a surgical arm joint, according to some embodiments of the invention; 
         FIG. 30  is a simplified schematic of a surgical system, according to some embodiments of the invention; 
         FIG. 31A  is a simplified schematic of an underside of a modular unit including a motor unit housing and a surgical arm, according to some embodiments of the invention; 
         FIG. 31B  is a simplified schematic of a linear unit, according to some embodiments of the invention; and 
         FIG. 31C  is a simplified schematic of a sliding element attached to a portion of a support, according to some embodiments of the invention. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION 
     A broad aspect of some embodiments of the invention relates to a system comprising one or more modular unit, each modular unit (also herein termed “surgical modular unit”) comprising a surgical arm and a motor unit configured for actuating movement of the surgical arm. 
     In some embodiments, at least two modular units are configured to be attached to each other. In some embodiments, each modular unit is configured to be operated separately. In some embodiments, the same surgical system is used to perform single port laparoscopic surgery (e.g. where all modular units being used in the surgery are attached and surgical arms inserted through a single port) and multiple port laparoscopic surgery. For example, multiple port laparoscopic surgery being performed when a first subset of the plurality of modular units is detached from a second subset of modular units, and surgical arms of the first subset are inserted through a different port to the second subset. In some embodiments, a plurality of detached subsets of modular units are inserted into a body through a plurality of ports. In an exemplary embodiment, a surgical system includes two modular units configured for surgical operation when attached and inserted into a body through a single port and when detached and inserted through two ports. 
     In some embodiments, the system includes a controller which sends a control signal to the plurality of motor units to control movement of the surgical arms. In some embodiments, the controller includes at least one input device arm, which, when moved sends an input device signal to the controller. In some embodiments, the controller generates the control signal based on the input device. In an exemplary embodiment, the controller includes two input device arms, where the control signal includes a first control signal instructing movement of a first surgical arm and a second control signal instructing movement of a second surgical arm, where the first control signal is generated based on measured movement of the first input device arm and the second control signal is generated based on measured movement of the second input device arm. 
     In some embodiments, the controller is configured to be used by one or more people. In some embodiments, the controller is configured to be used by one person when the input arms and/or modular units are attached and to be used by more than one person (e.g. two people) when the input arms and/or modular units are detached. 
     In some embodiments, a plurality of modular units are configured to, when attached, attach to a patient support (e.g. a bed) by a single support. 
     In some embodiments, modular units are coupled or attached mechanically. In some embodiments, modular units share coupling and/or alignment. In some embodiments, housing of motor units provides alignment of the modular units. In some embodiments, motor units are magnetically aligned e.g. using one or more magnet positioned in proximity to one or more motor unit housing. For example, in some embodiments, motors units are aligned to each other by aligning portions of a motor unit housing, for example, aligning one or more face of motor unit housings. 
     In some embodiments, modular units do not share power supply and/or do not share a connection with a controller. For example, each motor unit having a separate connection to one or more a power supply and/or one or more controller. 
     An aspect of some embodiments of the invention relates to a surgical system including a modular surgical arm configured to be attached to a modular motor unit which is configured to actuate the surgical arm. 
     For example, in some embodiments, a system includes a plurality of arms and a plurality of motor units where: One or more of the arms are compatible with more than one of the plurality of motor units and/or a plurality of the arms are compatible with one or more of the motor units. In some embodiments, modularity of surgical arms and/or motor units potentially enables, for example replacement of a surgical arm is replaced, for example, moving a surgical arm from one motor unit to another motor unit. In some embodiments, a system includes a plurality of arms and a plurality of motor units where each arm is compatible with more than one motor unit (e.g. each arm is compatible with each motor unit). 
     An aspect of some embodiments of the invention relates to attachment of a modular surgical arm to a motor unit. In some embodiments, a portion of the surgical arm is inserted into the motor unit. In some embodiments, the portion of the arm which is inserted into the motor unit includes surgical arm gears (e.g. includes a surgical arm gear unit) which are configured to actuate the surgical arm. In some embodiments, arm gears are configured to contact motor unit gears, once the surgical arm is inserted into the motor unit. In some embodiments, the portion of the surgical arm is elongate and is inserted into an elongated recess in a longitudinal face of a motor unit. 
     In some embodiments, actuating element/s of the motor unit contact the surgical arm, when the arm is inserted into the recess. For example, motor unit gears operably contact surgical arm gears. 
     For example, in some embodiments, one or more actuating element of the motor unit (e.g. motor gear) is exposed within the recess, for example, at least when the arm is inserted into the recess. In some embodiments, one or more actuatable element (e.g. surgical arm gear) is exposed on the surgical arm, at least once the arm is inserted into the motor unit recess. In some embodiments, once the arm is inserted into the recess, actuation elements of the motor unit contact the surgical arm, for example motor unit gears contact surgical arm gears. In some embodiments, insertion of the arm activates the motor unit, for example, a sensor detects that the surgical arm has been inserted and enables actuation of the arm by the motor unit. 
     In some embodiments, connection between surgical arm and the motor unit is along a length of the surgical arm and/or motor unit. For example where attachment is, between surgical gear unit and the motor unit. Potentially, connection being along a length of the arm and/or motor unit enables secure connection between the motor unit and the surgical arm, for example, potentially ensuring stability of a position of the surgical arm. Potentially, connection being along a length of the arm and/or motor unit enables contact between a plurality of motor unit actuating elements and the surgical arms (e.g. contact between a plurality of motor gears and surgical arm gears, where surgical arm and/or motor gears are axially separated and/or coaxial). 
     For example, in some embodiments, an angle of long axis of a portion of surgical arm (e.g. a surgical gear unit which, in some embodiments forms a distal end of the surgical arm) within a motor unit is 0-30° or 0-20° or 0-10° or lower or higher or intermediate angles or ranges, of a long axis of the motor unit. 
     For example, in some embodiments, a long axis of a surgical arm, when the arm is attached to the motor unit, is housed within the motor unit, extending within the motor unit for 80-99%, or 80-95% or 60-99% of a length of the motor unit. 
     For example, where 20-50%, or 25-40%, or about 35% or lower or higher or intermediate percentages or ranges, of a length of a surgical arm is attached to the motor unit. 
     In some embodiments, a kit provided to a user includes separate motor unit/s and surgical arm/s which are then assembled before use of the system. In some embodiments, surgical arm/s in the kit are provided sterile. 
     In some embodiments, one or more surgical arm is configured to operate using a plurality of tools (e.g. different tool types), where the tools, in some embodiments, are configured to be removably attached to a surgical arm. 
     An aspect of some embodiments of the invention relates to a motor unit configured to actuate a surgical arm where a surgical arm extends out of the motor unit at a first face of the motor unit, and where the motor unit is configured to be attached to another motor unit at a second motor unit face. In some embodiments, the first face of the motor unit generally defines a plane which is at an angle of 60-120°, 70-110° or 80-100° or about 90° or lower or higher or intermediate ranges or angles to a central axis (e.g. a central long axis) of at least a portion of the surgical arm extending from the first face. For example, a portion of the arm extending from the first face by 10 mm, or 20 mm, or 50 mm or 100 mm, or lower or higher or intermediate distances. In some embodiments, the second face is at an angle to the first face, for example at an angle of 60-120°, 70-110° or 80-100° or about 90° to the first face. In some embodiments, the motor unit has an elongated shape and the second face is a longitudinal face of the motor unit. 
     In some embodiments, the surgical arm is jointed at the face of the motor unit. 
     An aspect of some embodiments relates to parallel alignment between motor units in which a longitudinal face of a housing of one motor unit comprises a connection geometry suitable for engaging a face (e.g. a longitudinal face) of a housing of the second motor unit and/or suitable for engaging a connector. In some embodiments, the geometry comprises one or more elements for achieving an interference fit between the housings of the motor unit, such as respective protrusions and indentations. 
     In some embodiments, a face of a motor unit housing is a portion of the housing where 90-99%, or 90-99.5%, or 95-99% of a surface area of the housing varies by at most 0.1-2 mm, or 0.1-1 mm, or lower or higher or intermediate ranges or values from a plane of the face, where the plane is a tangential plane which contacts the largest surface area of the housing face. In some embodiments, a planar tangent of a motor unit housing longitudinal face is 0-5°, or 0-1°, from parallel to a central long axis of the housing. 
     In some embodiments, for example, in addition to the connection geometries on the second faces of the motor unit housing, the motor units are configured to interlock with each other, for example using mechanical means such as a plunger lock, pins and/or other fasteners. In some embodiments, the motor units interlock with each other using electromagnetic means. In some embodiments, interlocking between the motor units is released by a quick release mechanism, for example comprising a latch movable for releasing the lock. 
     In some embodiments, one or more connectors are used to connect two or more motors, e.g. at connection geometries on the motor unit housings. For example, in some embodiments, a connector connects two anchors one anchor located on each of two motor unit housings. In some embodiments, an anchor includes one or more indentation and/or protrusion. In an exemplary embodiment, an anchor is an indentation sized and shaped to receive a portion of a connector. 
     In some embodiments, a connector is configured to pull a plurality of motor units which it is attaching, together. For example, resistive forces from the connector in reaction to weight of the motor units on the connector acting to pull the motor units together. In some embodiments, a connector is a disposable component. In some embodiments, the connector is configured to be attached and detached from anchor/s. In some embodiments, the connector, once inserted is configured to be broken to detach the motor units from each other. For example, in some embodiments, a connector, once inserted, locks into position and, to be removed, is broken, a potential benefit being connectors which may not be reused. In some embodiments, a connector, once in position attaching a plurality of motor units, does not protrude from outer surfaces of the motor units. Alternatively, in some embodiments, a portion of a connector protrudes, for example, enabling removal of the connector and/or indicating presence and/or position of the connector. 
     In some embodiments, when a motor unit is attached to a second motor unit, the attached faces are in close contact, for example, where a separation between the attached faces is 0.01-2 mm or 0.01-1 mm, or at most 1 mm or at most 0.5 mm or lower or higher or intermediate distances or ranges. In some embodiments, when a motor unit is attached to a second motor unit, the attached faces directly contact each other. In some embodiments, the direct contact is for at least 90% of the surface area of the faces or at least 80% or at least 95% or at least 98% or 80-95%, or lower or higher or intermediate ranges or percentages. 
     In some embodiments, a motor unit housing faces, (in some embodiments, excluding portions of the faces with connection geometries) are sufficiently planar (e.g. deviating from planar by at most 2 mm or 1 mm or 0.5 mm or 0.1 mm or lower or higher or intermediate distances for at least 80% or 90% or 95% or 99% of a surface area of the plate, or lower or higher or intermediate percentages) that when the faces are connected they come into close contact (e.g. as quantified above). In some embodiments, connection geometries of two motor units are sized and/or shapes such that the faces, when connected at the connection geometries are in close contact (e.g. as quantified above). For example, in some embodiments, a protrusion on a first motor unit housing is fits into an indentation on a second motor unit housing sufficiently well, that the motor units when connected are in close contact. 
     In some embodiments, a single modular unit is used independently for performing surgery. Additionally or alternatively, multiple modular units such as 2, 3, 4, 6 units or intermediate or larger number of units are used for performing surgery. 
     In some embodiments, a motor unit is configured for detecting whether it has been connected to one or more additional motor units, for example via a sensor such as a microswitch. 
     In some embodiments, motor units are aligned by magnetic means, for example by one or more magnet acting at a motor unit face (e.g. longitudinal face). 
     An aspect of some embodiments relates to holding surgical arms close to each other such that a lateral distance between the arms (e.g. a lateral distance between longitudinal axes of the arms) is less than 10 mm, less than 5 mm, less than 1 mm or intermediate, longer or shorter distances. In some embodiments, each motor unit is collinear with the surgical arm actuated by the motor unit, so that when the arms are connected to the motor units they are held in a parallel position with respect to each other. In some embodiments, a motor unit is an elongate element, at least a portion of the surgical arm extending out of the motor unit is elongate. In some embodiments, a long axis of the elongate motor unit is parallel to a long axis of the elongate portion of the surgical arm extending out of the motor unit. 
     In some embodiments, the surgical arm extends distally from the motor unit at a lateral distance smaller than 5 mm, smaller than 3 mm, smaller than 1 mm from a longitudinal face of the motor unit which engages a respective longitudinal face of the second motor unit holding the second arm. In some embodiments, more than two arms are held close to each other such that the lateral distance between the arms is less than 10 mm, less than 5 mm, less than 1 mm or intermediate, longer or shorter distances. For example, in some embodiments, 3 or 4 or 5 or 3-10 surgical arms are held close to each other. 
     A potential advantage of the surgical arm positioned closely to the engaging face of the motor may include holding the arms of the adjacent motor units closely to each other, potentially allowing for insertion of the arms together through a relatively narrow opening to the patient body. For example, through a small incision of e.g. less than 5 cm in length and/or breadth, or less than 3 cm, or less than 2 cm, or less than 1 cm, or 0.1-5 cm, or 0.1-3 cm, or lower or higher or intermediate dimensions or ranges. For example, through a natural body orifice, e.g. the vagina, e.g. the anus, e.g. the trachea, e.g. the esophagus. For example, through an incision contained within the umbilicus. 
     In some embodiments, 3 motor units are constructed together to hold 3 surgical arms in proximity to each other. In an example, a first arm is defined to imitate the left arm; a second arm is defined to imitate the right arm; and a third arm carries a surgically assisting device such as a camera. 
     A broad aspect of some embodiments of the invention relates to interconnection of a plurality of motor unit modules in a variety of spatial configurations. In some embodiments, a motor unit is configured to interlock with one or more additional motor unit at a plurality of positions. For example, in some embodiments, a motor unit has a housing which includes a plurality of anchors which are, for example, located on different parts of the motor unit housing. 
     In some embodiments, a motor unit is configured to connect to other motor unit/s (e.g. includes a plurality of anchors) at different radial positions from a central long axis of the motor unit. For example, in some embodiments, a motor unit (e.g. a motor unit housing) has at least one anchor on more than one longitudinal face. 
     Additionally or alternatively, in some embodiments, a motor unit is configured to connect to other motor unit/s (e.g. includes a plurality of anchors) at different axial positions on the motor unit. For example, in some embodiments, a motor unit has a plurality of anchors distributed at different axial positions along a single longitudinal face of the motor unit. 
     In some embodiments, one or more anchor provides more than one connection geometry between motor units. In some embodiments, one or more anchor provides a range of connection positions e.g. a continuous range, for example, in some embodiments, one or more motor unit has an anchor configured for slide connection. 
     In some embodiments, a plurality of motor units are connected by one or more connector. In some embodiments, a single connector is configured to connect two motor units. For example, in an exemplary embodiment, a first and a second motor unit, having a first and a second slide connection anchor respectively, are connected by a connector which is sized and/or shaped to fit into the anchors thereby connecting the first and second motor units. In some embodiments, a plurality of connectors connect two motor units. 
     In some embodiments, a plurality of motor units are connected by placing the motor units into a connector, e.g. the connector is a sleeve sized and shaped to hold and/or interconnect a plurality of motor units. 
     In some embodiments, the surgical system includes a model of a configuration of attachment of the motor units. In some embodiments, the model is stored in a memory by a processor. In some embodiments, a model is selected by a user, for example, before and/or after connection (e.g. mechanical) of the modules. 
     In some embodiments, there are two modular units and the model includes a first and a second option, the first option where the modular units are connected, and the second option where the modular units are disconnected. 
     In some embodiments, a motor unit is configured, at a plurality of positions, for attachment to another motor unit. For example, in some embodiments, a plurality of attachments around a circumference of a motor unit are possible. 
     In some embodiments, a motor unit is configured for attachment to other motor units at multiple positions around a cross sectional circumference of the motor unit. In an exemplary embodiment, a motor unit includes four, equally spaced positions. 
     In some embodiments, motor units are attached to each other by one or more connector. In some embodiments, the connector is a separate part. In some embodiments, each motor unit includes one or more anchor, the anchor including an indentation, where a connector is shaped and/or sized to fit simultaneously into two anchors, e.g. thereby connecting two motor units. In an exemplary embodiment, attachment between the connector and the anchors includes slide attachment. In some embodiments, slide attachment enables axial adjustment of position and/or selecting of axial position of motor units with respect to each other. 
     A broad aspect of some embodiments of the invention relates to sizing and positioning of motor gears with respect to a surgical arm axis within a motor unit housing. Where, in some embodiments, motor gears drive surgical arm gears to effect movement of the surgical arm. In some embodiments, a plurality of surgical arm gear axes (e.g. all surgical arm gears for an arm) are collinear, where a gear axis is an axis about which the gear rotates. 
     In some embodiments, a longitudinal axis of a surgical arm and associated arm gears is positioned between one or more outer face (e.g. longitudinal face) of the motor unit housing and an axis or axes of motor gears driving the arm gears. 
     In some embodiments, one or more motor gear is sized such that a surgical arm is at a small lateral distance from a face (e.g. a longitudinal face) of a motor unit housing for example, 0.1-5 mm or 0.1-2 mm, or 0.5-2 mm, or lower or higher or intermediate distances or ranges. In some embodiments, a plurality of gears are sized such that a surgical arm is at a small lateral distance from a longitude face of the motor housing. For example, in embodiments, where an axis of one or more motor gear is between a surgical arm axis and a face of the motor unit, reduction in size of the motor gear reduces a distance between the surgical arm axis and the motor unit face. 
     In some embodiments, more than one motor gear drives a single surgical arm gear, for example, potentially enabling reduction in size of motor gears whilst maintaining a required level of torque. 
     In some embodiments one or more motor gear is small, for example a gear (or gears, or all motor gears of a motor unit, in some embodiments) having 1-20 mm diameter, or 1-5 mm diameter or lower or higher or intermediate diameters or ranges. In some embodiments, a motor unit has one or more motor gear (e.g. all motor gears of a motor unit) which is the same size or smaller than one or more surgical arm gear, for example, where the motor gear diameter is 20-100% or 20-95% or 40-70% of a surgical arm gear, or lower or higher or intermediate percentages or ranges. 
     A potential benefit of small motor gears is the ability to connect a motor unit to another other motor unit at a plurality of faces of the motor unit (e.g. all the faces of the motor unit) whilst maintaining the surgical arms close together. This potentially enables a large range of configurations of motor units where surgical arms are held closely together. 
     In some embodiments, motor gears are all collinear, potentially reducing a minimum required size of a motor unit and/or reducing a distance between a surgical arm axis and longitudinal face/s of a motor unit. 
     An aspect of some embodiments relates to automated actuation of linear movement of a system comprising one or more surgical arms. In some embodiments, a mechanism referred to herein as a “linear unit” is configured for actuating advancement and/or retraction of one or more modular units, for example advance and/or retract a surgical arm in and/or out of the patient body. In some embodiment, the linear unit is integrated in the motor unit. Additionally or alternatively, the linear unit is configured to be coupled to the motor unit. 
     In some embodiments, the linear unit comprises a rail and a sliding element positionable on the rail. In some embodiments, the sliding element connects to the motor unit so as to allow for sliding of the motor unit with respect to the rail. 
     In some embodiments, actuation of linear movement is driven by a motor. 
     Optionally, the motor is disposed in the motor unit such that when the motor unit is attached, via the sliding element, to the rail, the motor drives movement of the motor unit on the rail. 
     In some embodiments, the linear unit is configured for connecting to an external device or system. Optionally, the linear unit comprises a sensor, such as a microswitch, configured for detecting whether the linear unit was connected to an external device or system. 
     In some embodiments, a single linear unit is used for moving more than one motor unit, for example for moving two motor units attached together. 
     An aspect of some embodiments relates to constructing a modular system in accordance with a surgical approach. In some embodiments, a number and/or spatial arrangement of modular units and/or a number of surgical arms is selected in accordance with a selected surgical approach. 
     In some embodiments, selecting a surgical approach comprises selecting surgical port/s through which the surgery is performed. For example, including selecting a number and/or a shape and/or location of surgical port/s through which the surgery is performed. 
     A port may comprise a natural body orifice, an incised opening and/or any other opening allowing access to the patient&#39;s body. In some embodiments, a port comprises a port element which is, for example, coupled to the patient&#39;s body and through which one or more surgical arms accesses the patient&#39;s body. 
     In some embodiments, modular units are selected and/or arranged (e.g. spatially arranged) such that one or more surgical arms operate within a port. Additionally or alternatively, separate modular units are positioned at different ports. Additionally or alternatively, one or more surgical arms operate within a first port and then are moved to a second port. 
     In some embodiments, a spatial arrangement of modular units based on a shape and/or size of the port through which surgical arms associated with the modular units are inserted. 
     For example, in an exemplary embodiment, a linear spatial arrangement of modular units is selected, where units are sequentially connected in a line, for insertion into a patient through a linear port (e.g. linear incision) 
     In some embodiments, selecting a surgical approach includes selecting a surgical path (e.g. that surgical arm/s delineate) through a patient to a surgical target. In some embodiments, more than one surgical path is selected for example, multiple paths from one port (e.g. different arms inserted into a single port follow different paths within a patient body), for example, one or more path from each port where there are multiple ports. 
     In some embodiments, a spatial arrangement of modular units is selected based on selected surgical path/s. For example, in an exemplary embodiment, a linear spatial configuration of modular units is selected, for insertion into a patient when a narrow access profile is desirable, for example, where access is between ribs, for example, where a surgical path within the subject avoiding surgical obstacles is narrow. In some embodiments, a processer provides a recommended spatial configuration of modular units (one or more recommendation, e.g. displayed to a user), based on user inputted information including, for example, feature/s of a selected surgical path and/or approach, number of ports, size and/or position of ports, anatomical information, e.g. provided by imaging and/or anatomical maps. 
     In some embodiments, the system includes a user interface which is configured to display an indication of an attachment configuration of the plurality of modular units and/or motor units. In some embodiments, the user interface receives a model of an attachment configuration and then displays an indication of the attachment configuration based on the received model. Where, for example, the indication is an illustration of attached modular units and/or a numerical indication and/or one or more lit light. In some embodiments, the model received is based on signals produced by the modular units and received by a processor. For example, in some embodiments, a user positions and/or attaches a plurality of modular units, and one or more of the units sends a signal indicating their attachment configuration to the processor. In some embodiments, based on this signal, the processor generates and/or selects (e.g. from a list) a model of an attachment configuration. In some embodiments, a user selects an attachment configuration at a user interface, (for example, selecting the configuration from a list, for example, attaching virtual modular units in a virtual space), and the processor generates a model of an attachment configuration from the user input. In some embodiments, the user selected model of an attachment configuration is stored in a memory and/or displayed on a user interface. 
     In some embodiments, a model of an attachment configuration includes, for example, one or more of a number of modular units, an indication of which faces of which motor units are attached to each other, an indication of motor unit type, an indication of a surgical arm type. 
     In some embodiments, modular units are spatially arranged (e.g. for operation within a single port) by interlocking a plurality of modular units. In some embodiments, the surgical arms are pre-positioned and/or are moved to a selected position with respect to the ports for accessing the patient&#39;s body. In some embodiments, arms are configured for converging towards each other. Additionally or alternatively, arms are configured for diverging away from each other. In some embodiments, an arm portion (for example an arm portion extending between a motor unit and a first joint of the surgical arm) is configured to be shaped (e.g. bent) to a selected configuration. Some embodiments comprise a bendable over tube for setting a position of one or more arms with respect to the patient body and/or with respect to each other. 
     A broad aspect of some embodiments of the invention relates to control of movement of a modular unit surgical arms using a modular control units. In some embodiments, a configuration of a connected plurality of modular control units matches a configuration of connected surgical modular units. For example, in some embodiments, two surgical modular units are connected (e.g. at longitudinal faces of the surgical units) and movement of the surgical modular units is controlled by two connected modular control units. In some embodiments, a modular control unit includes an input device arm where a support of the input device arm is configured to attach the input device arm in proximity to another input device arm. In some embodiments, input device arms are configured to be attached to each other, where attachment is e.g. at their supports. 
     In some embodiments, modular units which are configured to be detached from each other, for example, potentially enabling cleaning of the modular units, for example, including surfaces which are close together and/or in contact with each other when the modular units (e.g. at motor unit housings) are attached (e.g. ease of cleaning of motor unit housing longitudinal faces). 
     An aspect of some embodiments of the invention relates to a surgical system including a plurality of surgical arms each arm attached to a motor unit configured to actuate the arm where one or more of the surgical arms includes a mechanically fixed curvature. 
     In some embodiments, the curvature brings arms towards each other, for example, a distal portion of the arms being at a smaller separation than a portion of the arms extending from the motor units. Potentially, in some embodiments, this smaller separation enables insertion of the arms through a single small port. 
     In some embodiments, the curvature increases a separation between the surgical arms, a distal portion of the arms being at a larger separation than a portion of the arms extending from the motor units, Potentially, in some embodiments, this larger separation enables insertion of the arms through more than one port and/or from more than one direction, whilst being actuated by connected motor units. 
     Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. 
     Referring now to the drawings,  FIG. 1A  is a simplified schematic side view of a device  100  (e.g. surgical device) including a plurality of arms, according to some embodiments of the invention. In some embodiments, the device includes a first arm  104  and a second arm  106 . 
     In some embodiments, one or both surgical arms are sized and/or shaped for insertion into a human body. 
     In some embodiments each arm  104 ,  106  includes a support segment  102 ,  103 , coupled to a first segment  112 ,  114  by a first connecting section  108 ,  110 , where first segment  112 ,  114  is coupled to a second segment  116 ,  118  by a second connecting section  120 ,  122 , and a third segment  124 ,  126  coupled to second segment  116 ,  118  by a third connecting section  128 ,  130 . 
     In some embodiments, one or more of support segments  102 ,  103  are rigid. In some embodiments one or more of support segments  102 ,  103  are flexible or include a flexible portion. 
     In some embodiments, support segments  102 ,  103  are coupled, e.g. by a cover  102   a . In some embodiments, support segments are coupled at only a portion of the torso length or are not coupled:  FIG. 1B  is a simplified schematic of a device  100  including a plurality of arms  104 ,  106 , according to some embodiments of the invention. 
     In some embodiments, one or more arm includes a humanoid like structure. For clarity, in some portions of this document, device segments and connecting sections are referred to by anatomical names: Support segments  102 ,  103  are also termed first torso  102  and second torso  103 , first connecting sections  108 ,  110  are also termed first shoulder joint  108 , second shoulder joint  110 , first segments,  112 ,  114  are also termed first humerus  112  and second humerus  114 , second connecting sections  120 ,  122  are also termed first elbow joint  120 , and second elbow joint  122 , second segments  116 ,  118  are also termed first radius  116  and second radius  118  and third segments  124  and  126  are also termed first hand tool  124  and second hand tool  126 . 
     In some embodiments, one or more connecting section includes a hinge. In some embodiments, one or more connecting section is flexible and/or includes a flexible portion. In an exemplary embodiment, a device arm includes an elbow joint and a shoulder joint where bending of the joint is distributed along the joint in a direction of a joint long axis. 
     In some embodiments, torsos  102 ,  103  are close together, for example, a long axis of first torso  102  and a long axis of second torso  103  are within 5 mm, or 3 mm, or 1 mm of each other. Alternatively, torsos  102 ,  103  are spaced apart from each other. 
     Additionally or alternatively, torsos  102 ,  103  are configured to converge or to diverge relative to each other. Optionally, a torso is curved. 
     In some embodiments, one or more device segment has a substantially cylindrical external shape (e.g. radius, humerus). In some embodiments, joints have circular long axis cross-section. Alternatively, in some embodiments, one or more device segment and/or joint has non-circular cross section external shape, for example, oval, square, rectangular, irregular shapes. 
     In some embodiments, a surgical arm includes one or more short and/or adjustable segment. In some embodiments, flexible portions are directly connected. 
     In some embodiments, a flexible portion comprises a plurality of stacked links. 
       FIGS. 1C-1D  are simplified schematic side views of surgical arms, according to some embodiments of the invention.  FIG. 1C  illustrates an exemplary embodiment where a humerus segment  112  is short, for example, the segment including a long axis length, J of 1-50 mm, or 1-35 mm, or 10-20 mm, or approximately 10 mm or lower or higher or intermediate ranges or lengths. 
     In some embodiments, a user selects arm/s including desired segment lengths, where for example, selection is based on patient anatomy and/or a procedure to be performed. For example, when treating a child a user, in some embodiments, selects one or more arm with one or more short segment (e.g. as illustrated by  FIG. 1C ). For example, when treating an obese patient, a user, in some embodiments, selects an arm with one or more a long segment for example, a standard arm with a long humerus segment (e.g. as illustrated by  FIG. 1D ) (e.g. humerus segment length, J′ is 10-100 mm, or 20-35 mm, or 10-20 mm, or lower or higher or intermediate ranges or lengths). 
     In some embodiments, a device includes a kit with different structured arms (e.g. different segment lengths, e.g. different arm sizes). 
     Alternatively or additionally, in some embodiments, one or more segment length is adjustable, e.g. during a treatment and/or during set-up of the device. For example, in some embodiments, the arm illustrated in  FIG. 1C  is adjustable (e.g. by telescoping of humerus segment  112 ) is adjustable to the configuration illustrated in  FIG. 1D . 
     In some embodiments, extension and/or retraction of one or more segment is effected by a portion connected to the segment (e.g. a segment extension) being moved with respect to other portions of a surgical arm. For example, in some embodiments, a segment extension is moved (e.g. by a motor located in a motor unit) to increase a length of a segment. In some embodiments, a motor uses a screw mechanism to move the segment extension. 
     In some embodiments, a device arm has at least the freedom of movement of human arms. Generally, segments of human limbs (e.g. arms, legs) move by flexion and extension from a proximal segment joint, and rotation around the proximal segment joint. For example, a human radius flexes and extends at the elbow and rotates around the elbow. 
     The term proximal joint herein refers to the joint which is least removed from the torso to which a segment is coupled, e.g. a hand proximal joint is the wrist, a radius proximal joint is the elbow joint, a humerus proximal joint is the shoulder joint. 
     The term proximal segment herein refers to the segment which is least removed from the torso to which a segment is coupled (e.g. by a proximal segment joint). For example, a hand proximal segment is the radius, a radius proximal segment is the humerus, a humerus proximal segment is the torso. 
     In some embodiments, one or more joint is uni-directionally bendable and extendable. In some embodiments, segment rotation around a segment proximal joint is achieved by rotation of a proximal segment around a proximal segment long axis. For example, rotation of the hand around the wrist joint is by rotation of the radius around a radius long axis. 
     Generally, human freedom of movement for arms includes limits to the angles of rotation and flexion. Optionally, in some embodiments, the device is restricted to human freedom of movements e.g. during one or more control mode. Alternatively, the device is configured to allow movement having additional degrees of freedom relative to human arm movement. 
       FIG. 2A  is a simplified schematic of a device  200 , held by a support  282 , according to some embodiments of the invention. 
     In some embodiments, support  282  attaches to a portion of a patient operating surface, e.g. rail  202 . In some embodiments, position of attachment of support  282  on rail  202  is adjustable, for example enabling linear adjustment of position of attachment of the support to the patient operating surface. 
     In some embodiments, support  282  is attached to port  212  of a motor construct  214 , device  200  being supported by attachment to motor construct  214 . In this example, motor construct  214  comprises two motor units configured for actuating two arms of device  200 , according to some embodiments. It is noted that in some embodiments, the device comprises a different number of arms such as 1, 3, 4, 6, 8 arms or intermediate, higher or lower number. Optionally, each arm is actuated by a respective motor unit. 
     In some embodiments, port  212  is placed at an opening to the patient&#39;s body, for example at an incision and/or at a natural body orifice such as the vagina and/or anus and/or mouth. In some embodiments, port  212  is attached to the patient&#39;s body using sutures and/or other attachment means. Additionally or alternatively, port  212  is fixated to the operating surface  202 . 
     In some embodiments, support  282  includes a plurality of articulations where angles between segments and/or segment lengths are adjustable, for example, enabling adjustment of position and/or angle of a device  200  including surgical arms and/or a port  212  and/or motor construct or construct  214  (e.g. which actuate device 200 arm/s). 
     In some embodiments, one or more motor is used to move device  200 , with respect to one or more portion of the system (e.g. with respect to port  212  and/or motor construct  214 ), for example, into and/or out of a patient. In some embodiments, motor construct  214  includes one or more motor for movement of one or more device arm with respect to the motor construct, where, for example, one or more support segment position is changed with respect to the motor construct. In some embodiments, movement of device  200  is controlled by a user, optionally using input object control and/or a user interface. 
     In some embodiments, the motor unit includes one or more position sensor. In some embodiments, a position sensor is placed adjacent the motor for sensing a current rotation angle of the motor. In some embodiments, the position sensor is magnetically operated, using a magnet placed on the motor gear and sensing the magnetic flux to determine a current position of the motor gear. 
     In some embodiments, the motor unit is controlled by a processor including a memory which stores commands. In some embodiments, data from position sensor/s and/or from control memory is used to infer a position of device portion/s. In some embodiments, the motor unit is controlled by a processor configured in the user&#39;s input device. 
     In some embodiments, motor unit includes structure (e.g. including electrical contact/s), for example, for delivery of monopolar and/or bipolar energy to the device (e.g. to a device end effecter). 
     In some embodiments, support  282  is configured to move motor construct  214  linearly, for example to advance device  200  into and/or out of the patient&#39;s body. In some embodiments, linear movement is obtained by a linear unit  290 . 
       FIGS. 2B-2C  illustrate actuation of a device by linear unit  290 , according to some embodiments. 
     In some embodiments, linear unit  290  defines a rail  270  on which an element  272  coupled to motor construct  214  is slidably received. Optionally, linear movement (e.g. sliding) of motor construct  214  relative to linear unit  290  is actuated by a motor  296 . In some embodiments, motor  296  is a component of motor construct  214 . In an example, in a motor construct comprising 12 motors for actuating articulation of two surgical arms (e.g. 6 motors driving movement of each arm), motor  296  is a 13 th  motor. 
     Optionally, motor  296  is disposed externally to a housing of the motor unit.  FIG. 2B  illustrates motor construct  214  at an initial position with respect to linear unit  290 . In  FIG. 2C , motor construct  214  has been moved in a distal direction (e.g. slid) to an advanced position relative to linear unit  290 . 
     A potential advantage of motorized entry and/or retraction from the body using the linear unit may include obtaining a higher degree of movement accuracy, for example as compared to manually-actuated entry into the body. 
     In some embodiments, linear movement of the motor construct which in turn actuates linear movement of the arm(s) is performed concurrently with one or more other articulations provided by support  282 , as shown in  FIG. 2A . Such actuation may be advantageous, for example, during insertion into the body, providing for example for simultaneous bending and advancing into the body. 
       FIG. 3A  is a simplified schematic view of a system  350  where a device  300  is held by a support  382 , according to some embodiments of the invention. 
     In some embodiments, a device  300  is coupled to a bed  380 . In some embodiments, a patient  360  lies on bed  380  for surgical procedures using device  300 . 
     In some embodiments, one or more component of the device, for example one or more part of device control (e.g. motors) is located underneath bed, e.g. in a housing  384 . In some embodiments, support  382  connects device  300  to housing  384 . 
     Optionally, other components, for example transformers, connectivity to other components e.g. the display, are located in housing  384 . 
     In an exemplary embodiment, a main motor unit (or a motor construct comprising a plurality of motor units) for control of movement of the device is located in housing  384 , where for example, in some embodiments, torque transfer element/s transfer torque from motor/s within housing  384  to device  300  and/or elongated elements for effecting flexion of device joints are coupled to motors within housing  384 . 
     In some embodiments, control of movement of the device above the bed, using a motor unit underneath the bed is via an orientation controller, for example using a parallelogram linkage, e.g. as described in International Patent Application Publication No. WO2011/036626 which is herein incorporated by reference into the specification in its entirety. 
     A potential benefit of one or more component being located underneath a bed (e.g. inside housing  384 ), is reduced footprint of the system in an operating room. A further potential benefit of components being located underneath a bed as opposed to above and/or around the bed is potentially improved access to a patient (e.g. in an emergency situation). 
     A potential benefit of the device being coupled to a bed is the ability to move and/or change an angle of the bed, for example, during surgery, while the device remains in the same position relative to the bed and/or patient. Alternatively, or additionally, in some embodiments, a device position with respect to the patient and/or the bed is adjustable, for example, before treatment with the device and/or during surgery. 
     Optionally, in some embodiments, support  382  moves device into position for surgery. In some embodiments, support  382  moves device into a desired position for insertion into patient  360 . In some embodiments, support  382  moves device vertically, and/or horizontally, and/or laterally, and/or inserts device  300  into a patient  360  and/or withdraws device  1100  from the patient. 
     In the embodiment illustrated by  FIG. 3A , support arm  382  and housing  384  are located at the foot end of  384 . A potential benefit of this location is ease of surgery through a patient&#39;s undercarriage, for example, through the vagina. 
     In  FIG. 3A , patient  360  is illustrated in a suitable position for insertion of the device into the vagina, the patient&#39;s legs are elevated and apart (e.g. held by stirrups which are not shown). 
       FIG. 3B  is a simplified schematic view of a system  350  where a device  300  is held by a support  382 , according to some embodiments of the invention. In the embodiment illustrated by  FIG. 3B , support arm  382  and housing  384  are located at a long axis center of the bed  380 . A potential benefit of this location is ease of abdominal and/or thoracic surgery using the device. 
     In some embodiments, a housing position underneath the bed and/or a position around the bed from where the arm meets the housing are adjustable. For example, the arm and/or housing are moved for different surgeries. 
       FIG. 4A  is a simplified schematic cross sectional view of an arm  404  with nested segment extensions, according to some embodiments of the invention.  FIG. 4B  is a simplified schematic of a side view of a portion of an arm, according to some embodiments of the invention. Dashed lines illustrate the portion of the arm illustrated in  FIG. 4A  illustrated by  FIG. 4B . 
     In some embodiments, arm  404  includes a hand tool  424  coupled to a radius  416  at a wrist joint  428 . 
     In some embodiments, radius  416  is coupled to a radius extension including two torque transfer portions; an elbow torque transfer portion  416 ETT disposed inside an elbow joint  420  and a shoulder torque transfer portion  416 STT disposed inside a shoulder joint  408 . In some embodiments, radius  416  is coupled to a humerus  412  by a connector  416 C. In some embodiments, portion  416 C connects radius  416  to humerus  412  whilst allowing free rotation of humerus  412 . In some embodiments, at region A of  FIG. 4A , protrusion/s on radius portion  416  fit into indentation/s on portion  416 C. In an exemplary embodiment, a ring shaped protrusion on radius portion  416  (e.g. a ring of material connected (e.g. welded) to radius portion  416 ) fits into an indentation on portion  416 C. Similarly, in some embodiments, portions  412 C and  412  are connected by matching protrusion/s and indentation/s (e.g. a ring protrusion on portion  412  fitting into a matching indention in portion  412 C). 
     In some embodiments, a “connecting section” includes a connector and a joint, for example shoulder joint  408  and connector  412 C, for example elbow joint  420  and connector  416 C. 
     In some embodiments, hand tool  424  is actuated (e.g. opened and/or closed) by rotation of a hand tool extension (not illustrated). In some embodiments, the hand tool extension includes one or more torque transfer portion. In some embodiments, the hand tool portion is nested in a center of the surgical arm. Alternatively or additionally, in some embodiments, a hand tool is actuated by changing tension on one or more elongated element coupled to portion/s of the hand tool. 
       FIG. 4C  is a simplified schematic cross sectional view of a portion of an arm, according to some embodiments of the invention. In some embodiments, for example, a portion includes a ring protrusion which fits into an indentation on portion  416 C. 
     In some embodiments, portion  416 C provides anchoring to one or more elongated element: for example, where elongated element/s (e.g. a cable, a wire, a tape) are connected/coupled to portion  416 Canc. 
     In some embodiments, one or more connector couples portions whilst allowing one portion to rotate within the connector about the portion&#39;s long axis. For example connecting portion  416 C allows radius  416  to rotate within connecting portion  416 C about a radius long axis. 
     In some embodiments, humerus  412  is coupled to a humerus extension including one torque transfer portion, a shoulder torque transfer portion  412 STT disposed inside shoulder joint  408 . In some embodiments, the humerus is coupled to a torso  402  by a connector  412 C. 
     In some embodiments, a surgical arm includes a first and a section flexible portion (e.g. elbow joint and shoulder joint) which are coupled together with a short connecting segment (e.g. a humerus section coupling a shoulder and elbow joint is short). In some embodiments, coupling between the flexible portions is a point connection (e.g. a shoulder and elbow joint are directly connected). 
     In some embodiments, a rigid anchoring portion (e.g. portion  416 C) connects two flexible portions, where the anchoring portion provides anchoring of elongated elements which control flexion and extension of the joint which is, for example, proximal to the elongated portion. In some embodiments, anchoring is provided by a portion of one of the joints, e.g. a distal portion of the proximal joint. 
     In some embodiments, one or more shafts (or portions thereof) of the surgical arm are rigid. In some embodiments, a flexible shaft is nested within a rigid outer shaft. 
     In some embodiments, the outer shaft is flexible to a lower extent than the inner shaft. 
       FIG. 5A  is a flowchart of a method of constructing a modular system in accordance with a surgical approach, according to some embodiments of the invention. 
     In some embodiments, a surgeon (and/or other clinical personnel) decide on a surgical approach ( 500   a ). In some embodiments, one or more incisions are made to provide access to the target tissue. Additionally or alternatively, access to the target tissue is obtained via a natural body orifice, such through vaginal and/or anal and/or oral orifices. In some embodiments, a port (such as  212 ,  FIG. 2A ) is inserted and/or coupled to the natural orifice and/or to the incision. Potentially, the port prevents and/or reduces movement with respect to the patient of (e.g. supporting portions) of tools inserted through it. Optionally, in some embodiments, the port is coupled to a portion of the system, for example, a patient support surface. 
     In some embodiments, the target tissue is approached via a combination of one or more incisions with entry via one or more natural orifices. 
     In some embodiments, the surgical device is constructed in accordance with the selected surgical approach ( 502   a ). In some embodiments, the device is constructed by coupling one more modular units to each other, for example coupling 2, 3, 5, 6 or intermediate or larger number of modular units together. In some embodiments, a modular unit comprises an arm coupled to a motor unit which is configured for actuating articulation of the arm. Additionally or alternatively, a modular unit comprises any combination of arms and/or motor units which make up an independent assembly, configured to be used alone as well as with additional modular units. 
     In some embodiments, the constructed device comprises multiple sets (e.g. 2, 3, 4, 6) of arms coupled to respective motor units that are attached together, for example so that the device comprises 3 arms actuated by 3 corresponding motor units, 5 arms actuated by 5 corresponding motor units, etc. Additionally or alternatively, more than one arm (e.g. 2, 3, 5 arms) are configured to be actuated by a single motor unit. 
     Additionally or alternatively, more than one motor unit actuates a single arm. For example, in some embodiments, an arm has and/or is coupled to an arm base. In some embodiments, an arm base includes a motor unit. In some embodiments, more than one arm is coupled to a single arm base which arm base includes one or more motor units. 
     In some embodiments, the modular units are configured to connect to each other by a mechanical attachment. In some embodiments, the mechanical attachment comprises one or more elements configured on a housing of a motor unit, for example a protrusion on a first motor unit received in respective indentation on a second motor unit, a connector which concurrently fits into a plurality of indentations on different motor units, an interference fit coupling, a slide fit coupling, and/or other attachment configurations. 
     In an exemplary embodiment, attachment between two motor units includes slide attachment where a protrusion on a first motor unit is sized and/or shaped to fit into a slot on a second motor unit. In some embodiments, a depth of the slot decreases along a length of the slot towards a step where the depth of the slot decreases (e.g. abruptly, e.g. in a step). In some embodiments, a spring loaded latch on the first motor unit protrusion prevents the motors units from sliding apart, once the protrusion is slid into the slot. 
     Additionally or alternatively, the motor units are connected to each other via electromagnetic means, such as electromagnetic locks. Optionally, an electromagnet portion of the lock is coupled to a housing of a first motor unit, and a mating armature is coupled to a housing of a second motor unit. In some embodiments, the electromagnetic lock is used for identifying whether another motor unit was attached. 
     Alternatively, constructing comprises decoupling modular units previously attached to each other, for example by a quick release mechanism. In some embodiments, the quick release mechanism comprises unfastening a latch, for example to release a mechanical coupling between the motor units. In some embodiments, the quick release mechanism comprises pressing a button and/or switch to deactivate an electromagnetic coupling. In some embodiments, constructing comprises coupling a linear unit, for example unit  290  as shown in  FIG. 2B , to one or more of the motor units. 
     In some embodiments, a number and/or structure of modular units from which the device is constructed is selected in accordance with the selected surgical approach. 
     In some embodiments, the number of arms is selected so that each of the arms is inserted through an opening to the body (e.g. through an incision and/or through a natural orifice). Additionally or alternatively, the number of arms is selected so that more than one arm is inserted through an opening, for example two arms are inserted through the vagina. Additionally or alternatively, the number of units is selected so that one or more arms are configured to be inserted through a first opening and then moved to additional one or more openings. 
     In some embodiments, the number of arms is selected in accordance with the number of tools required for performing the operation. In an example, 3 end tools such as a camera, graspers and suction/irrigation are operated by, for example, 3 arms. 
     In some embodiments, construction of the motor construct is performed during set up of the procedure. Optionally, construction is performed in the operation room before and/or after the patient enters the room. In some embodiments, construction or deconstruction of the motor construct is performed during the procedure, for example when changing a surgical approach, such as changing from a single port procedure to a multi-port procedure or vice versa. 
     In some embodiments, for example, during the procedure (e.g. a surgical procedure) a surgical arm is replaced and/or removed from a surgical area. For example, in some embodiments, a modular surgical arm is detached and/or removed from a motor unit. Optionally, in some embodiments, before the surgical arm is removed from a motor unit, it is retracted from a surgical zone within a patient and/or removed from the patient&#39;s body, optionally, while other arm/s remain in situ and/or are employed. In some embodiments, a surgical arm is removed from a first motor unit and attached to a second motor unit, with and/or without retracting the arm from the patient. In some embodiments, a surgical arm is removed from a motor arm and is replaced with a second surgical arm which is attached to the motor unit, optionally without moving and/or retracting the motor unit from an initial position. 
     In some embodiments, a surgical arm tool is removed and/or replaced and/or moved to a different surgical arm. For example, in some embodiments, optionally, during a procedure, optionally when arm/s remain inside a patient, a surgical arm tool is removed from a surgical arm. In some embodiments, the tool is then moved and attached to a second surgical arm. In some embodiments, the tool is replaced with a second tool which is then attached to the arm. 
     In some embodiments, when an arm is removed and/or moved and/or replaced, a user enters into an input device an identifier of, for example, the arm/s and/or motor units involved and/or an indication of the action taking place, for example, removal and/or replacement and/or moving to a different motor unit. In some embodiments, an arm includes a physical identifier, e.g. an RFID tag, a barcode which, in some embodiments, is scanned by a reader in, for example, one or more of a user interface and/or motor unit. In some embodiments, a signal providing identifier/s of the arm/s involved and/or of the motor unit/s involved is sent by the motor unit and/or sensors in the arm and/or by an external sensor (e.g. RFID reader) to a processor which, in some embodiments, stores the identifiers in a memory. In some embodiments, the processor and/or memory are located at a control console. 
     Additionally or alternatively, in some embodiments, when a tool is removed and/or moved and/or replaced a user enters into an input device an identifier of, for example, the tool/s, arm/s and/or motor units involved and/or an indication of the action taking place, for example, removal and/or replacement and/or moving to a different surgical arm. In some embodiments, a tool includes a physical identifier, e.g. an RFID tag, a barcode which, in some embodiments, is scanned by a reader in, for example, one or more of a user interface and/or motor unit. In some embodiments, a signal providing identifier/s of the tool/s and/or arm/s involved and/or of the motor unit/s involved is sent by the motor unit and/or sensors in the arm and/or by an external sensor (e.g. RFID reader) to a processor which, in some embodiments, stores the identifiers in a memory. 
     In some embodiments, the processor and/or memory are located at a control console. 
     In some embodiments, the one or more arms are inserted into the body through the one or more openings, optionally via one or more entrance ports configured at the one or more openings ( 504   a ). 
     In some embodiments, the arms are activated to perform the surgical procedure ( 506   a ). In some embodiments, mechanical arm movement is directed by a user&#39;s (e.g. surgeon) arm movement, optionally via an input device. 
     In some embodiments, each motor unit is connected (via a wired or wireless connection) to a different communication port in the device controller. In some embodiments, the device controller is configured to recognize the number of arms attached. In some embodiments, the device controller is configured to automatically assign arm pairs, for example defining left and right arms. Additionally or alternatively, the device controller receives an arm pair assignment from the user. Optionally, the assignment is changed in real time (e.g. right arm is redefined as left arm, and vice versa). For example, a user changes selected surgical arms by pausing control (e.g. control of movement of surgical device arm/s by mapped input object movement) of one or more selected surgical device arm and re-selecting one or more surgical device arm. In some embodiments, the user pauses and re-selects arms to switch control of a first device arm by a left user arm and control of a second device arm to control of the second device arm with the user right arm and control of the second device arm by a user left arm. 
     In some embodiments, a user pauses an initial surgical device arm in a desired position (e.g. to hold user anatomy in position) and selects another surgical device arm (e.g. a third arm) for continued two-arm movement. 
     In some embodiments, the device control recognizes a current device structure (e.g. number of arms, left and right assigning of arms, a current posture of each arm) by identifying one or more driver circuits of a motor unit actuating an arm. 
     In some embodiments, the device controller is configured for cross-control of a plurality arms, for example, two arms can be activated or deactivated by a single safety switch. In some embodiments, cross-control is provided via the user input device. In an example, a single activation (e.g. pushing once) of a button on the input device imitating the right arm and/or on the input device imitating the left arm is configured to deactivate both surgical arms; recurrent activation (e.g. a pushing the button twice) is configured to deactivate the respective arm only (e.g. right surgical arm or left surgical arm). 
     Optionally, a structure of the device is modified during operation ( 508   a ). 
     Optionally, the structure is modified in accordance with the surgical approach, for example, if a first stage of the surgery is performed via a plurality of openings (e.g. incisions and/or natural orifices) and a second stage of the surgery is performed via a single opening, one or more modular units are attached for the first stage and separated for the second stage. 
       FIG. 5B  illustrates exemplary surgical approaches, according to some embodiments. In some embodiments, a single incision is made, for example a single umbilical incision as shown in  510   a . In some embodiments, multiple incisions are made, for example as shown in  512   a . For example, in some embodiments, a first device arm is inserted through a first incision and a second device arm is inserted in a second incision. In some embodiments, the device is inserted through a single incision and additional tools, for example a tool for inflation of the abdominal cavity are inserted through one or more separate incision. 
     In some embodiments, the one or more device arms are inserted through an incision without having to enlarge the incision. In some embodiments, for example as shown in  514   a , an incision larger than necessary for insertion for the device is made. For example, the largest extent of the incision on the skin surface is larger than 1 cm or more, or 2 cm or more, or 10 cm or more, or 20 cm or more. In some embodiments, the device is used where at least a portion of the inserted device and/or portion of the device under a skin level is visible to a user. Optionally, e.g. when the device is at least partially visible, the system lacks an imager inserted into the body and/or images are not displayed to the user. 
       FIG. 5C  schematically illustrates actuation of a surgical arm  500 , according to some embodiments. 
     In some embodiments, a proximally extending shaft extension  502  (e.g. an extension of a torso  503 ) of arm  500  is attached to a motor unit  504 . In some embodiments, proximal shaft extensions of arm segments that are nested within extension  502  (e.g. a proximal shaft extension  506  of humerus  507 , a proximal shaft extension  508  of radius  509  that is nested within humerus extension  506 , a proximal shaft extension  510  of a hand portion  511  that is nested within radius extension  508 , and so forth) are actuated by a plurality of actuation mechanisms of the motor unit, such as 3 actuation mechanisms  520 ,  522  and  524 . In some embodiments, the number of actuation mechanisms is set in accordance with the number of joints of the arm, for example, as shown herein, an arm including 3 joints (e.g. shoulder, elbow and wrist joints) is actuated by 3 actuation mechanisms, an arm including 4 joints is actuated by 4 actuation mechanisms, an arm including 2 joints is actuated by 2 actuation mechanisms, an arm including 1 joint is actuated by a single actuation mechanism. 
     In some embodiments, an actuation mechanism  520  (shown in the enlarged view) is configured to move at least a segment of arm  500 , for example rotate the segment and/or bend the segment and/or otherwise move the segment. In some embodiments, an actuation mechanism comprises one or more actuators, for example 1, 2, 3, 4, 5 and/or 6 actuators. In some embodiments, the actuators are independently operable, yet, in some embodiments, a shaft manipulation (e.g. rotation, bending) obtained by a first actuator effects control of one or more other actuators. 
     In some embodiments, actuators of the same actuation mechanism are actuated together. Additionally or alternatively, actuators of different actuation mechanisms are actuated together, for example to provide for articulation of a proximal arm segment, a distal arm segment (which is at least partially nested within the proximal arm segment) needs to be moved as well. In an example, to provide for flexion of the shoulder, a bending actuator of an elbow is actuated as well. 
     In some embodiments, for example as shown herein, shaft extensions  502  and  506  (which is nested, in part, within shaft extension  502 ) are received within actuation mechanism  520 . In some embodiments, actuation mechanism  520  comprises a first actuator  540 , and a second actuator  542 . In some embodiments, first actuator  540  is configured to rotate an arm portion, such as rotate the torso by rotating shaft extension  502  around its axis. In some embodiments, second actuator  542  is configured to bend an arm portion, such as bend a shoulder joint at a distal end of the torso (not shown herein). Optionally, bending is achieved by respective linear movement of elongate elements  544  and  546 , which extend from actuator  542  and are connected distally to the joint. 
     In some embodiments, a prime mover of an actuator such as  540  and/or  542  comprises a motor  532 . In some embodiments, a speed of motor  532  ranges between, for example, 10-100 rpm, such as 20 rpm, 50 rpm, 70 rpm, 80 rpm or intermediate, higher or lower speeds. In some embodiments, motor  532  is configured to apply a torque between 0.5 N*M to 3 N*m, such as 1 N*m, 1.5 N*m, 2 N*m or intermediate, higher or lower values. In some embodiments, motor  532  is a continuous rotation motor. 
     Additionally or alternatively, a prime mover of an actuator comprises a linear motor. Additionally or alternatively, a prime mover of an actuator comprises a pulley. 
     In some embodiments, the prime mover of an actuator is manually operated, for example comprising one or more cables that are pulled on to actuate movement of the gear. 
     In some embodiments, a single motor is configured to move more than one actuator (e.g. rotate both the bending and rotation gears). In some embodiments, dual-actuation is enabled by use of a locking mechanism and another motor configured for switching between the actuators, based on the selected articulation (e.g. bending or rotation). 
     In some embodiments, motor  532  is positioned parallel to the shaft extension, for example underlying the shaft extension, overlying the extension and/or positioned beside the extension. Alternatively, motor  532  is disposed within an internal lumen of the shaft extension. Alternatively, the shaft extension is configured as a part of the motor, for example contained within an external housing of motor  532 . 
     In some embodiments, an actuator comprises a single gear or a gear train. In some embodiments, the gear train is configured to amplify the input torque generated by motor  532 . Alternatively, the gear train is configured to reduce the input torque generated by motor  532 . In some embodiments, the gear train is configured to reduce the rotation speed generated by the motor. In an example, the motor speed is 12,000 RPM, and the gear or gear train reduce the speed by a ratio of, for example, 134:1, 43:1, 9:1 and/or intermediate, higher or lower ratios. In an example, a gear or gear train actuating movement of an end-effecter of the arm such as grippers is configured to reduce the speed by a ratio of 9:1, enabling fast opening and closure of the gripper. This may be advantageous, for example, when dissecting tissue using the gripper. 
     Alternatively, in some embodiments, the gear train is configured to increase the output speed generated by the motor. In an example, the output speed of the motor is increased for autonomous electrical ablation of tissue. 
     In some embodiments, actuators of an actuation mechanism comprise gears or gear trains that are different from each other. In some embodiments, the motors of the two actuators are rotated at similar speeds, but the “final” movement manipulating gears of each actuator are rotated at different speeds. In an example, actuator  542  comprises a gear transmission while actuator  540  is driven directly by the motor. In another example, the actuators each comprise a single gear, but the gears are of different sizes and/or shapes (e.g. comprising different number of teeth). 
     In an example, actuator  540  comprises a gear that is configured to rotate shaft extension  502  directly, rotating at a speed, of, for example, 2000 RPM; actuator  542  comprises a gear that is configured to actuate bending by linearly moving elongated elements  544  and  546 , optionally by rotation of a threaded screw coupled to the elements for example as described hereinbelow, and due to this additional transmission the gear of actuator  542  needs to rotated faster than gear  540 , for example rotated at a speed of 4000 RPM. 
     In another example, an actuator that actuates an end-effecter such as a gripper is configured to rotate at a relatively fast speed, for example 9000 RPM for enabling fast movement. 
     Alternatively, in some embodiments, it is desired to actuate an end-effecter at a relatively low speed, for example for action requiring applying of relatively large force via the end-effecter, such as separating tissue, stapling tissue, and/or other actions. 
     In some embodiments, actuators  540  and  542  are rotated on a single rotational axis  548 . In some embodiments, axis  548  is also the rotational axis of shaft extensions  502  and  506 . 
     In some embodiments, actuation mechanisms  520 ,  522 ,  524  of the motor unit are collinear. 
     In some embodiments, the motor unit includes one or more position sensor  552 . 
     In some embodiments, position sensor  552  is placed adjacent the motor for sensing a current rotation angle of the motor. 
     In some embodiments, the position sensor is magnetically operated, using a magnet placed on the motor gear and sensing the magnetic flux to determine a current position of the motor gear. 
     In some embodiments, the motor unit is controlled by a processor  550  including a memory which stores commands. 
     In some embodiments, data from position sensor/s and/or from control memory is used to infer a position of device portion/s. 
     In some embodiments, the motor unit is controlled by a processor configured in the user&#39;s input device. 
       FIG. 29  is a simplified schematic side view of an actuation mechanism for control of a surgical arm joint, according to some embodiments of the invention. 
     In some embodiments, a rotation gear  2902  is coupled to a shaft  2904 , where shaft  2904  is coupled to an extension (e.g. to torso  402 ,  FIG. 4A ). In some embodiments, rotation of rotation gear  2902  causes rotation of shaft  2904  which in turn rotates the distal extension coupled to the shaft. 
     In some embodiments, a shaft  2980  which is nested, at least in part, within shaft  2904  extends in the proximal direction to a bending gear  2906 . 
     In some embodiments, bending gear  2906  is coupled to a portion including screw threading, referred to herein as threaded screw  2908 . In some embodiments, a threading on screw  808  comprises a double thread. In some embodiments, rotation of the double thread in one direction achieves bidirectional lateral movement of one or more rider elements, such as half-nuts referred to hereinbelow, coupled to the screw. 
     In some embodiments, a pitch  882  of the screw thread is selected according to the use of the arm. For example, a small thread pitch is more advantageous when the arm is configured to operate large loads, for example a load of 2000 grams, 1500 grams, 3000 grams or intermediate, larger or smaller loads at a low speed (e.g. 0.5 rounds per second, 1 round per second, 0.2 rounds per second). Alternatively, a large thread pitch is more advantageous when the arm is configured to operate small loads, for example 100 grams, 50 grams, 300 grams or intermediate, larger or smaller loads at a higher speed (e.g. 2.5 rounds per second, 4 rounds per second, 5 rounds per second). 
     In some embodiments, rotation of the bending gear  2906  causes rotation of threaded screw  2908 . In some embodiments, a first half nut  2910  and a second half nut  2912  are coupled to screw threaded screw  2908  such that rotation of the screw threading generates linear movement of half-nuts parallel to a long axis  2914  of central shaft  2904 , where first half-nut  2910  and second half-nut  2912  move in different directions. 
     In some embodiments, each of the half-nuts is limited to movement in a single direction, for example a right handed half-nut and a left handed half-nut. In some embodiments, movement of the half-nuts is limited by one or more protrusions, for example protrusions extending radially inward from an inner wall of housing  2916 , for example as further described herein. 
     In some embodiments, first half nut  2910  and second half nut  2912  are connected to elongated elements  2910   ee  and  2912   ee  respectively, where linear movement of the nuts pulls one elongated element whilst releasing and/or pushing on the other, generating flexion/extension of the joint. In some embodiments, a distance  820  between the half-nuts, measured along an axis perpendicular to the long axis, defines the distance between the elongated elements. In some embodiments, distance  820  between the elongated elements remains constant. In some embodiments, first nut  2910  is configured remain in line with elongated element  2910   ee , and second nut  2912  is configured to remain in line with elongated element  2912   ee.    
     In some embodiments, an elongated element such as  2910   ee  and/or  2912   ee  comprises a wire, cable, ribbon, tape and/or any other element which can be tensioned and released to provide for bending of the joint. 
     It is noted that in some embodiments, only one elongated element is used. In an example, the mechanism comprises one elongated element and an elastic element such as a spring. Optionally, the spring is configured to move relatively to the elongated element, for example if the elongated element is flexed, the spring is extended and vice versa. It is also noted that in some embodiments, more than two elongated elements (e.g. 3, 4, 6, 8) may be used. 
     In some embodiments, actuation of the rotation gear rotates the arm segment and thereby pulls on the elongated elements, moving the half-nuts. If the bending gear is held stationary (e.g. by the motor gear), the threaded screw will not rotate, generating simultaneous rotation and bending of the arm segment. If the bending gear is free to rotate, pulling on the elongated elements will in turn move the half-nuts, rotating the threaded screw. Friction at interface  2984  between a head of the threaded screw and bending gear  2906  will in turn rotate the bending gear, generating rotation of the arm segment as one piece. 
     In some embodiments, one or both of the elongated elements is coupled to an elastic element such as a spring. Optionally, the spring is configured to limit tensioning of the elongated element(s), yielding in response to a force (e.g. torque and/or pulling force) above a certain threshold. 
       FIG. 6A  is a simplified schematic side view of a motor construct  600  for actuation of a device including surgical arms, according to some embodiments of the invention. As referred to in  FIGS. 6A-6D , motor construct  600  is comprised of two modular units, each comprising a motor unit coupled to an arm and configured for actuating movement of the arm, according to some embodiments. 
     In some embodiments, a device including a first surgical arm  604  and a second surgical arm  606  are controlled by motor construct  600 .  FIG. 6B  is a detailed view of motor construct  600 , according to some embodiments. 
     In some embodiments, a first motor unit  690  configured for actuating arm  604  comprises, for example, 3 actuation mechanisms  601   a ,  601   b ,  601   c . In some embodiments, similarly, second surgical arm  606  is actuated by a motor unit  692  comprising three actuation mechanisms. Optionally, the motor units are parallel to each other. Optionally, the motor units are arranged such that the actuation mechanisms are symmetrically arranged along a long axis  650  of motor construct  600 . 
     In some embodiments, a first actuation mechanism  601   a , including first rotation gear  602   a  and first bending gear  606   a , drives flexion/extension and rotation of a shoulder joint. Referring now to  FIGS. 4A-4B , for example, in some embodiments, first actuation mechanism  601   a  rotates the shoulder joint by rotating torso  402  and effects flexion and extension of shoulder joint  408  by movement of elongated elements attached to connector  412 C. 
     In some embodiments, a second actuation mechanism  601   b , including second rotation gear  602   b  and second bending gear  606   b , drives flexion/extension and rotation of an elbow joint. In some embodiments, one or more driving gear coupled to a motor  670  is disposed underneath the motor unit  690 . For example, in some embodiments, a gear which drives second bending gear  606   b , which gear is coupled to a motor is disposed on an underside of the motor unit  690 . For example, gear  699  drives a second actuation mechanism corresponding to second surgical arm  606 . 
     Referring now to  FIGS. 4A-4B , for example, in some embodiments, second actuation mechanism  601   b  rotates the elbow joint by rotating humerus  412  and effects flexion and extension of elbow joint  420  by movement of elongated elements attached to portion  416 C. 
     In some embodiments, a third actuation mechanism  601   c , including third rotation gear  602   c  and third bending gear  606   c , actuates an end effecter (e.g. opens and closes a gripper) and drives rotation of a wrist joint. Referring to  FIG. 4A , in some embodiments, rotation gear  602   c  rotates radius  416  and bending gear  606   c  actuates hand tool  424 ; For example, in some embodiments, rotation of third bending gear  606   c  opens and closes an end effecter. 
     In some embodiments, similarly, second surgical arm  606  is actuated by three actuation mechanisms, including, for example, 6 motors. In an exemplary embodiment, for example as shown herein, a device for insertion into the body includes two surgical arms, actuated by 12 motors. 
     In some embodiments, one or more additional motor (e.g. a 13th motor) moves the device arms towards and/or away from the motor unit. For example, in some embodiments, a position of attachment of the motor unit (e.g. to a support and/or to a patient support surface) is changed e.g. by a motor. 
     In some embodiments, the device comprises a single arm actuated by a motor unit comprising 6 motors (e.g. 2 motors per each actuation mechanism). In some embodiments, a 7 th  motor is used for linearly moving the arm, for example towards and/or away from the motor unit and/or from the patient&#39;s body. In some embodiments, one or more additional motors (e.g. an 8 th  motor, a 9 th  motor) are used. Optionally, the additional motor(s) actuate movement of an end-effecter of the arm around a pivot point (fulcrum movement), for example around the incision. 
     For example, referring to  FIGS. 2A-2C , in some embodiments, a position of attachment of support  282  with respect to rail  202  is changed (e.g. by a motor located on support  282 ). For example, in some embodiments, a position of attachment of motor unit  214  with respect to support  1482  is changed (e.g. by a motor located on support  282 ). 
     For example, moving the device into and/or out of a patient body e.g. when the motor unit is supported in a fixed configuration and/or to automate movement of the device into the patient. In some embodiments, a motor located within motor construct  600  moves the device arms into and/or out of a patient. 
     In some embodiments, for example, so that rotation of a joint also causes rotation of joints distal of the rotated joint, more than one actuation mechanism is driven in rotation of the joint. For example, in some embodiments, for rotation of the shoulder joint, gears  602   a ,  606   a ,  602   b ,  606   b ,  602   c ,  606   c  are rotated in the same direction. For example, in some embodiments, for rotation of the elbow joint, gears  602   b ,  606   b ,  602   c ,  606   c  are rotated in the same direction. For example, in some embodiments, for rotation of the end effecter, gears  602   c ,  606   c  are rotated in the same direction. In some embodiments, concurrent rotation of nested portions with outer portions prevents stress on and/or tangling of internal elongated elements (e.g. elongated element/s which are used to effect flexion/extension, e.g. elongated element/s providing power supply). 
     In some embodiments, one or more actuation mechanism is used to flex/extend a joint. For example, in some embodiments, to bend a shoulder joint, elongated elements for bending of both the shoulder joint and elbow joint are moved, for example by actuating bending gear  606   a  and bending gear  606   b.    
     In some embodiments, if elongated elements for the elbow are not moved and/or released, tension in the elongated elements associated with the elbow joint resist movement of the shoulder joint. 
     In some embodiments, a motor unit is small. In some embodiments, a motor unit comprises a long axis length  650  of between 100-600 mm, or 200-400 mm, or 300-500 mm, or 150-400 mm, or intermediate, longer or shorter length. 
     In some embodiments, for example as shown herein, a motor construct comprising two parallel arrangements for actuating two arms comprises a width  652  (e.g. as measured perpendicular to the long axis) between 20-100 mm, or 30-80 mm, or 50-70 mm, or intermediate, longer or shorter size. 
     In some embodiments, motor  670  is cylindrical. Optionally, a diameter of motor  670  is less than 17 mm, less than 35 mm, less than 10 mm or intermediate, larger or smaller diameters. A potential advantage of disposing a motor of a relatively small diameter in a parallel position relative to the arm may include maintaining the dimensions of the motor unit small. 
     Alternatively, the motor is not cylindrical, for example rectangular. In some embodiments, the motor comprises a hollow shaft. A potential advantage of a hollow shaft may include reducing the footprint of the system in the operating room. 
     In some embodiments, electrical power is supplied through wires to the motor units, for example, in some embodiments, contacts  620  are connected to an electrical power supply. The electrical power supply may include a battery (optionally rechargeable) and/or a generator and/or connection to the electrical network via a wall socket and/or a combination thereof. In some embodiments, the power range is between 100-300 W, for example 150W, 200 W, 250 W or intermediate, higher or lower ranges. In some embodiments, an uninterruptible power supply source is used to protect from power interruptions. 
     In some embodiments, a motor construct drives more than two surgical arms and/or drives additional device elements. For example, in some embodiments, a motor construct drives two device arms and a camera. 
       FIG. 6C  is a cross-section of the motor construct along the length of the construct, showing first motor unit  690 , according to some embodiments. 
     In some embodiments, the motor unit comprises a motherboard  622 , optionally underlying the actuation mechanisms. In some embodiments, one or more driver circuits  624  are operably coupled to motherboard  622  for controlling operation of the motor unit. In some embodiments, each driver circuit is configured to control activation of one of the motors (e.g. one of the 6 motors described hereinabove). In some embodiments, cross-control of the motors is provided. In an example, a position sensor of a first motor is controlled by a controller of a second motor. Optionally, in such configuration, malfunctioning of the first motor can be detected by the controller of the second motor. In some embodiments, malfunction of the first motor is detected by the controller of the second motor. 
     In some embodiments, an external housing  626  of the motor unit comprises a handle  628  for attaching and/or releasing arm  604  from a distal end face  630  of the motor unit. 
     In some embodiments, one or more latches  632  are configured on external housing. Optionally, latch  632  is configured to release a gear fixation mechanism used, for example, during attachment of the surgical arm to the motor unit to maintain calibration of the motor unit, for example as further described herein. 
       FIG. 6D  is a cross section of the motor construct  600  along an axis perpendicular to the long axis, according to some embodiments. 
     In some embodiments, the motor construct is configured to actuate two surgical arms; in this example, one surgical arm  604  (an extension of which) is shown to be received within the first motor unit  690 , while the second opposing motor unit  692  is shown in a configuration suitable for receiving a second arm, for example received within internal lumen  640 . 
     It is noted that in some embodiments a motor unit configured for actuating a single arm is comprised of only of one of the sides of the motor construct shown herein, including, for example, 3 actuation mechanisms. 
     In some embodiments, for example as shown herein, actuation gears  672  and  676  of motors  670  and  674  respectively are each configured to drive a gear of an actuation mechanism, for example actuation gear  672  of motor  670  is configured to drive rotation gear or bending gear  678  (such as gear  602   a  or  606   a  or  602   b  or  606   b  or  602   c  or  606   c ). 
     In some embodiments, latch  632  configured at motor unit  690  which, in this illustration, includes the arm, is shown at a closed position. In some embodiments, a closed positioned of the latch releases a fixation mechanism of gear  678 , allowing it to rotate freely. As further shown in this figure, a second latch  634  configured at the second motor unit  692  is shown at an open, lifted position. 
     In some embodiments, a motor such as  674  is disposed such that it does not extend to a distance  682  longer than 5 mm, 10 mm, 20 mm or intermediate, longer or shorter distances relative to a central long axis of an actuation mechanism, for example passing through a center  680  of rotation/bending gear. A potential advantage of a motor disposed adjacent an actuation mechanism, optionally in parallel to the actuation mechanism such that it substantially does not protrude outwardly or protrudes outwardly to a short distance only may include reducing bulkiness of the motor unit, potentially allowing insertion of the surgical arm(s) as well as the motor unit into the body during operation. 
     In some embodiments, the motor unit is coupled to a linear unit  680   a , configured for actuating linear movement of the motor unit (and thereby of the arm(s)), for example actuate advancement and/or retraction of the device to and/or from the patient body. In some embodiments, linear unit  680   a  comprises a rail  682   a  on which a sliding element  684  coupled to the motor unit can be moved linearly. In some embodiments, movement (e.g. sliding) of the motor unit on the rail of the linear unit is actuated by a motor. 
     Alternatively, in some embodiments, the linear unit is an integral component of the motor unit. 
     In some embodiments, the linear unit comprises one or more sensors, such as microswitches, for detecting movement of the motor unit. In some embodiments, the linear unit comprises one or more actuation buttons configured to provide for a user (e.g. nurse) to move the motor unit according to the need. In some embodiments, the motor driving the linear movement (not shown herein) comprises an electro-magnetic brake. Optionally, the brake is configured to avoid unwanted movement (e.g. slipping) of the motor unit, for example during a power outage. 
       FIG. 31A  is a simplified schematic of an underside  3102  of a modular unit  3100  including a motor unit housing  3104  and a surgical arm  3106 , according to some embodiments of the invention. In some embodiments, the motor unit includes a linear unit  3108 . In some embodiments, one or more portion of a linear unit is disposed within a motor unit housing and one or more portion of the linear unit extend outside of motor unit housing e.g. second portion  3108   b.    
       FIG. 31B  is a simplified schematic of a linear unit  3108 , according to some embodiments of the invention. Motor unit housing is not illustrated in  FIG. 31B . In some embodiments, linear unit  3108  includes a sliding element  3110  coupled to a motor  3112  where motor  3112  is configured to move the sliding element  3108  on a rail  3114 . 
     In some embodiments, sliding element  3110  is coupled to motor  3112  by a screw mechanism where the motor rotates the screw to move the sliding element on the rail. In some embodiments, sliding element  3110  includes a first portion  3108   a  which, in some embodiments, is located within a motor unit housing and a second portion  3108   b  which, in some embodiments, is located outside the motor unit housing. In some embodiments, second portion  3108   b  is fixed to a support (e.g. support  282   FIG. 2A , e.g. support  382   FIG. 3A ) and movement of sliding element  3108  moves the modular unit with respect to the support. 
       FIG. 31C  is a simplified schematic of a sliding element  3108  attached to a portion of a support  3116 , according to some embodiments of the invention. In some embodiments, support portion  3116  includes an anchor  3118  which is sized and/or shaped to receive second portion  3108   b . In some embodiments, support portion has one or more overhanging edge  3120 . In some embodiments, reactive force of overhanging edge/s to the weight of the modular unit holds the modular unit onto the support portion. 
     In some embodiments, second portion  3108   b  is slid into anchor  3118 . In some embodiments, support portion is sized and/or shaped that second portion  3108   b  is placed into anchor  3118  and then slid underneath overhanging sides. In some embodiments, support portion  3116  and second portion  3108   b  include a locking mechanism which locks the two portions together. For example, in some embodiments, a spring loaded protrusion (on one portion) which fits into a matching indentation (on the other portion). 
     In some embodiments, a system includes a plurality of motor units, each including an integral linear unit. In some embodiments, when a plurality of motor units are connected, a single linear unit (e.g. which is integral to one of the motor units) is used to actuate linear movement of the motor construct (including a plurality of connected motor units). For example, referring to  FIG. 31A , in some embodiments, when modular unit  3100  is connected to an additional modular unit, only second portion  3108   b  of modular unit  3100  (and not a second portion of the additional modular unit) is attached to a support portion, the actuation of  3108   b  moving the motor construct of the two attached motor units. 
       FIGS. 7A-7D  are diagrams of various configurations of systems comprising different combinations of modular units, according to some embodiments of the invention. 
       FIG. 7A  is a diagram of a configuration comprising two arms actuated by two motor units which are coupled to each other (for example as shown hereinabove in  FIG. 6A ). In some embodiments, the motor units are closely coupled to each other in a manner that approximates the arms and holds them adjacent each other. In some embodiments, a linear unit (for example unit  290  as described hereinabove in  FIGS. 2A-2C ) is coupled to one or both of the motor units. Optionally, the linear unit is configured to move the device as a whole (e.g. advance and/or retract both motor units as one piece). 
     In some embodiments, the linear unit is configured to be removably coupled to the motor unit. Optionally, the linear unit comprises a motor configured for actuating the linear unit. In some embodiments, the motor unit comprises an additional controller configured for controlling the motor of the linear unit (e.g. a 7 th  controller, for example in a motor unit comprising 6 motors controlled by 6 respective controllers). In some embodiments, the additional controller (e.g. 7 th  controller) is configured to detect if a linear unit was attached to the motor unit, for example by electrically detecting attachment of the motor of the linear unit to the arm motor unit. 
     A configuration for example as shown in  FIG. 7A  may be especially advantageous for use in operations performed through a single opening (e.g. a natural orifice or a single incision), such as SILS (Single Incision Laparoscopic Surgery) or vaginal operations, for example hysterectomy. 
     In  FIG. 7B , two separate modular units are used, according to some embodiments. In some embodiments, the linear unit is an integral part of the motor unit. In some embodiments, for example in a system structured for operating through a single port, (e.g. in which the motor units are attached to each other to approximate the arms to each other), only one of the linear units is used for actuating the motor construct comprising the two attached motor units. A potential advantage of using only one of the linear units for actuating movement may include reducing unintentional use of the linear units, for example instructing one motor unit to move proximally and the other motor unit to move distally. 
     In some embodiments, the motor unit comprises a sensor (e.g. a microswitch) configured for detecting whether a linear unit was operably coupled to an outer connector. A potential advantage of a sensor configured for detecting attachment of the linear unit to an outside component may include detecting an architecture of use, for example detecting if the system is configured for a single-port approach (e.g. comprising motor units coupled to each other to define a construct moveable by a single linear unit) or a multi-port approach (e.g. comprising separate motor units, each configured to be moved by a respective linear unit). In some embodiments, a shape and/or size of the outer connecter is selected so that only a predefined number of linear units can be attached to it, for example one linear unit, two linear units and/or other number of units. In an example, when a motor construct comprising two linear units (e.g. of two motor units) is used, the outer connector may be shaped and/or sized to enable only one of the linear units to be attached. Limiting the connection to the outer connector, for example by using an outer connector of a selected shape and/or size may be advantageous in reducing user mistakes (e.g. connecting two linear units of two motor units that are coupled together, for example for use in a single port approach). 
       FIG. 7C  is a diagram of a configuration in which both motor units are coupled to linear units, according to some embodiments. Optionally, the linear units are configured to move (e.g. advance and/or retract) each of the motor units independently of each other. A configuration for example as shown in  FIG. 7C  may be especially advantageous for use in operations in which multiple openings are used, for example in surgical operations such as multi-quadrant surgeries, operations for treating tissue adhesions in the abdomen and/or in the umbilicus. 
       FIG. 7D  is a diagram of a configuration comprising a first modular unit including an arm, a motor unit and a linear unit; and a second modular unit comprising a motor unit configured to actuate two arms, according to some embodiments. 
     In some embodiments, a motor unit or construct is not coupled to a linear unit. 
     Optionally, the motor unit or construct is coupled to a manual sliding mechanism. 
       FIGS. 8A-8B  illustrate an exemplary configuration including two modular units, in which the motor units  804  and  806  are attached to each other. Optionally, the units are attached by one or more of an interference fit between the housings of the motor units, mechanical attachment means (e.g. screws, pins, fasteners and/or other connectors), and/or electromagnetic means. Additionally or alternatively, the motor units are held together by an external housing (not shown) in which the motor units are received. 
     In some embodiments, an arm such as arm  800  is positioned at a distance  803  from a longitudinal face  807  of motor unit  804 . Optionally, distance  803  is smaller than 7 mm, smaller than 5 mm, smaller than 2 mm, or intermediate, longer or shorter distances. Optionally, when the two motor units are aligned adjacent each other, arms  800  and  802  which coupled to motor units  804  and  806  respectively are held closely to each other by the motor units, for example so that a distance  805  between the arms, along an axis perpendicular to the long axis of the arms, is less than 20 mm, less than 8 mm, less than 1 mm, or intermediate, longer or shorter distances. 
       FIGS. 9A-9B  illustrate an exemplary configuration of a system including two separate modular units  900  and  902 , each comprising an arm  904  operated by a motor unit  906 . In some embodiments, during operation, each modular unit is situated at a different location relative to the bed (for example bed  380 ,  FIGS. 3A-3B ) and/or relative to the patient. In some embodiments, the units are situated with respect to different surgical ports, for example in a manner in which each arm is configured to enter a different port. Insertion of surgical arms via different ports may be advantageous in operations in which force (e.g. traction) is applied in one direction and a counter force is applied in the opposite direction (e.g. when treating tissue adhesion). 
       FIG. 28A  is a simplified schematic of an exemplary configuration of a system including two separate modular units configured to be attached to each other, according to some embodiments of the invention. In some embodiments, a first modular unit includes a first surgical arm  2800  and a first motor unit  2804  and a second modular unit includes a second surgical arm  2802  and a second motor unit  2806 . In some embodiments, the units are attached using more than one attachment, for example, more than one slide attachment  2810 ,  2808 . 
     In some embodiments, a plurality of attachments are not aligned on a motor unit longitudinal face. For example, as illustrated in  FIG. 28A , attachment  2810  is closer to a top face  2816  of motor unit  2804  than a second attachment  2808 . Potentially, having a plurality of attachments with different positions both parallel to a long axis and perpendicular to a long axis of the motor unit longitudinal face on which they are located increases attachment strength under loading from directions including a components perpendicular to a plane of the longitudinal face and a component parallel to a plane of the longitudinal face. 
     In some embodiments, surgical arms and/or motor units are modular. In some embodiments, one or more surgical arm is configured to be removably attached to a motor unit.  FIG. 28E  is a simplified schematic of a plurality of modular surgical arms  2802 ,  2804 , according to some embodiments of the invention. In some embodiments, a surgical arm  2804  includes a gear unit  2822  which includes surgical arm gears  2810 . In some embodiments, surgical arm gears  2810 , when arm  2804  is connected to a motor unit, actuate the arm (e.g. as described with reference to  FIG. 5C  and  FIG. 29 ). In some embodiments, arm  2804  includes one or more handle, for example, two handles  2812 ,  2814  e.g. configured for grasping by a user, one in each hand. In some embodiments, handles  2812 ,  2814  and/or a side of the arm opposing exposed portions of arm gears  2810  has an outer surface which is an insulating material. For example, meaning that, when arm  2804  is inserted into a motor unit (e.g. as illustrated in  FIGS. 7A-7B ) electrically live portions of the device are not at a surface of the device. 
     In some embodiments, each motor unit receives electrical power from and/or control signals at one or more connection point, for example, connection points  2801 ,  2803 ,  2805 , where, in some embodiments, each connection point is configured to be connected to a cable. In an exemplary embodiment, first connection point  2801  is configured to be connected to a monopolar power supply, second connection point  2805  is configured to be connected to a bipolar power supply and third connection point  2803  is configured to receive power and/or control signals. In some embodiments, power and/or control signals received at the third connection point are delivered (e.g. by connections within the motor unit) to motors within the motor unit. 
     In an exemplary embodiment, a long axis length, L 1 , of the surgical arm is 500-1000 mm, or 650-800 mm or about 728 mm or lower or higher or intermediate ranges or lengths, a length, L 2 , of a surgical arm gear unit  2822  is 150-350 mm, or 200-300 mm or about 260 mm or lower or higher or intermediate ranges or lengths, and a thickness, T 1 , of a body of surgical arms is 5-12 mm or 7-9 mm or about 8.2 mm or lower or higher or intermediate ranges or thicknesses. 
     Referring back now to  FIG. 28B , in some embodiments surgical arm  2800  fits into a recess within motor unit  2804  such that gears of the surgical arm contact gears of motor unit  2804  (gears not visible in  FIG. 28A ). 
     In some embodiments, a surgical arm is inserted into a recess (e.g. recess  2804 ) in a motor unit by holding the arms above the face of the recess and lowering the arms into the recess. Alternatively, in some embodiments the arm is held in front of a face of the motor unit from which the surgical arms extend and are then pushed into the recess. 
     In some embodiments, the recess includes one or more protrusion and/or indentation which is configured to prevent the surgical arm from being inserted incorrectly into the recess. For example, a stopper which prevents insertion of the arm past a desired point. 
     In some embodiments, connection between surgical arm  2800  and motor unit  2804  is along a length of the surgical arm and/or motor unit. 
     For example, in some embodiments, an angle of long axis of a portion of surgical arm (e.g. surgical gear unit  2822  which, in some embodiments forms a distal end of the surgical arm) within a motor unit is 0-30° or 0-20° or 0-10° or lower or higher or intermediate angles or ranges, of a long axis of the motor unit. 
     For example, in some embodiments, a long axis of a surgical arm, when the arm is attached to the motor unit, is housed within the motor unit, extending within the motor unit for 80-99%, or 80-95% or 60-99% of a length of the motor unit. 
     For example, where attachment is between surgical gear unit  2822  and the motor unit. For example, where 20-50%, or 25-40%, or about 35% or lower or higher or intermediate percentages or ranges, of a length of a surgical arm is attached to the motor unit. 
     In some embodiments, surgical arm  2800  is mechanically held in position by one or more component. In some embodiments, motor unit  2804  includes one or more clamping hammer  2852 ,  2854  which contact and/or apply pressure to the surgical arm. 
     In some embodiments, clamping hammers  2852 ,  2854  are brought into contact and apply pressure to surgical arm  2800  when a flap  2850  is rotated about a hinge attachment to motor unit  2804  to a closed position illustrated in  FIG. 28A . 
     In some embodiments, motor unit  2804  includes a sensor detecting whether a surgical arm has been attached. In some embodiments, motor unit  2804  includes a lock clamping hammer  2856  which, by movement of flap  2850 , is brought into contact with a sensor (e.g. a microswitch). In some embodiments, this sensor provides a signal to a processor (e.g. located within a motor unit and/or located within a control console) indicating that flap  2850  is in a closed position holding the arm onto the motor unit. 
     In some embodiments, the system will issue an alert to a user and/or stop use of the surgical arm/s if the sensor indicates that flap  2850  is open. In some embodiments, surgical arms are only enabled for use (movement and/or electrosurgery is enabled) upon a processor receiving a signal that the flap is closed. 
     In some embodiments, lock clamping hammer  2856  is configured to be held in position by a component inserted through a hole within it. In some embodiments, locking of lock clamping hammer  2856  holds the flap and/or surgical arm in position. 
       FIG. 28B  is a simplified schematic cross section of a motor construct, showing attachment  2808 ,  2818  between motor units, according to some embodiments of the invention.  FIG. 28C  is an enlarged view of the attachment  2808 ,  2818  of  FIG. 28B , according to some embodiments of the invention.  FIG. 28D  is a simplified schematic of a slide attachment, according to some embodiments of the invention. 
     In some embodiments, a protrusion  2808  on motor unit  2804  fits into an indentation  2818  on second motor unit  2806 . In some embodiments, motor units are held together and slid past each other thereby protrusion  2808  into indentation  2818 . In some embodiments, protrusion  2808  is held under a lip  2820  surrounding indentation  2818 , where the lip (or lips if there are a plurality of such attachments, e.g. as illustrated in  FIG. 28A ) are sufficiently strong to hold the motor units together. In some embodiments, a first end of protrusion  2808  is tapered, potentially easing alignment and/or insertion of the protrusion into the indentation. 
       FIGS. 10A-10C  are exemplary mechanical arm layouts, according to some embodiments. 
     In some embodiments, one or more arm portions such as an arm portion extending between the motor unit and the first arm joint (e.g. shoulder joint), defined herewith as torso  1000 , comprises a non-linear configuration. 
     In some embodiments, torso  1000  is performed with one or more curvatures, for example set during factory calibration. Additionally or alternatively, torso  1000  is bent by the user, manually and/or via the user input device, before and/or during operation. 
     In some embodiments, for example as shown in  FIG. 10A , torso  1000  of one of the both of the arms is curved such that the arms converge towards each other. 
     Additionally or alternatively, for example as shown in  FIG. 10B , torso  1000  of one or both arms is curved such that the arms diverge away from each other. Optionally, a parallel alignment between more distal portions  1002  and  1004  of the arms (e.g. an arm portion distally to the shoulder joint) is maintained. 
     Additionally or alternatively, for example as shown in  FIG. 10C , torso  1000  of one or both the arms is curved such that the arms diverge away from each other and then converge towards each other, positioning arm portions  1002  and  1004  at a different orientation relative to each other, for example arm portion  1004  is positioned at an angle α relative to arm portion  1002 . In some embodiments, angle α ranges between, for example, 0-90 degrees, such as 20 degrees, 55 degrees, 80 degrees or intermediate, larger or smaller angles. 
     An arm layout for example as shown in  FIG. 10A  may be advantageous for use in a single-port surgical approach. Arm layouts as shown in  FIGS. 10B and 10C  may be advantageous for use in a multi-port surgical approach. 
     In some embodiments, a curved portion of the torso comprises torque transferring portions and/or elements for transferring torque from the motor unit to more distal arm portions. In an example, the torque transferring portion comprises stacked annular segments. 
     In some embodiments, for example as shown in  FIG. 10B , an over tube  1006  positioned to over lie at least a portion of torso  1000 . In some embodiments, over tube  1006  is rigid. In some embodiments, over tube  1006  is pre-shaped to define a fixed curvature. Optionally, over tube  1006  is fixedly attached to the motor unit, for example via one or more attachments  1007 . In some embodiments, over tube  1006  is not affected by actuation of the motor unit, while the torso extending throughout the over tube is affected, for example the torso is rotated around its axis by actuating the rotation gear. 
       FIGS. 11A-11B  are a simplified schematic side view of a device  1100  including 3 arms  1104 ,  1105 ,  1106 , actuated by 3 respective motor units,  1120 ,  1122 ,  1124 , according to some embodiments. 
     In some embodiments, an arm comprises a tool, optionally disposed at a distal end of the arm, for example, as shown herein, arms  1104  and  1106  each comprise a gripper  1130 , and arm  1178  carries a camera  1178 , according to some embodiments. 
     In some embodiments, for example as shown herein, motor construct  1150  comprises two motor units  1120 ,  1124  configured for actuating movement of arms  1104  and  1106  respectively, and a third motor unit  1122  configured for actuating movement of arm  1105  which carries the camera. Optionally, motor unit  1122  comprises a single actuation mechanism for actuating movement of joint  1110 . 
     In some embodiments, as also shown in this figure, a torso  1102  of arm  1105  comprises one or more curved portions  1152 . Optionally, torso  1102  is curved to allow for positioning arm  1105  (and thereby position camera  1178 ) at a selected location and/or orientation and/or distance with respect to arm  1104  and/or to arm  1106 . 
     In some embodiments, movement of a mechanical arm including a camera is controlled by measured movement of a user&#39;s head. For example, by movement of a user&#39;s head in space and/or by movement of a user&#39;s head with respect to one or other body part (e.g. torso and/or neck). 
     In some embodiments, movement of a mechanical arm including a camera is controlled by measured movement of a user&#39;s limb (e.g. arm). For example, the arm includes at least a first and a second flexible portion, the movement of which is controlled by a user shoulder and elbow joint respectively. 
     Additionally or alternatively, in some embodiments, movement of a mechanical arm including a camera is controlled by movement of portion/s of an input device. 
     Additionally or alternatively, in some embodiments, a position of one or more tool inserted into a patient body (e.g. a camera, e.g. a mechanical arm, e.g. a tube) is controlled by one or more device arm. For example, in some embodiments, a tool is grasped by one or more device arm and moved into a desired position. For example, in some embodiments, a tool (e.g. a camera) includes an elastically deformable portion such that, upon positioning of the tool the tool remains in position until the tool is repositioned. For example, in some embodiments, a suction tube is positioned by a surgical arm moving the tube. In some embodiments, a tool (e.g. a tube) includes one or more elastically deformable portion, such that, for example, the tool is moved into a desired position by a movement of a mechanical device arm, returning towards an original position once the tool is released. 
       FIGS. 12A-12E  schematically illustrate different approaches for using one or more mechanical arms in a multi-port surgery, according to some embodiments. 
     In  FIG. 12A , 3 arms  1200  are actuated by 3 respective motor units  1202 . 
     Optionally, each arm is configured to enter the patient&#39;s body through a different port  1204 , according to some embodiments. 
     In  FIG. 12B , 3 arms are actuated by a single motor unit. Optionally, each arm is configured to operate at a different port, according to some embodiments. In some embodiments, a single motor unit configured for actuating more than one arm (e.g. 2 arms, 3 arms) comprises elongated channels for guiding the plurality of proximal extensions of the arms during insertion to the motor unit. Optionally, each extensions is positioned in contact with driving gears (or, in some embodiments, driven gears) configured to actuate movement of the specific arm. Some embodiments comprise a locking mechanism which locks the arm extension in position. Optionally, the locking mechanism is configured to lock each extension separately. A potential advantage of a locking mechanism configured for locking each of the extensions separately may include the ability to replace an arm (e.g. if the arm malfunctions and/or if a different type of tool needs to be used) while maintaining the other arms active. Alternatively, the locking mechanism is configured to lock all extensions in position simultaneously. 
     In  FIG. 12C , 2 arms are actuated by a motor construct comprising two motor units, and a third arm is positioned separately from the two arms and is actuated by its own motor unit. Optionally, each arm is configured to enter through a different port. 
     Alternatively, the two adjacent arms are configured to operate at the same port, and the third arm is configured to operate at a different port. Alternatively, all three arms operate through the same port. 
     In  FIG. 12D , a single arm actuated by a single motor unit is configured to be moved between multiple ports, for example, after operating through a first port the arm is moved and/or curved to reach a second and/or third port, according to some embodiments. 
     In  FIG. 12E , 3 arms are actuated by 3 respective motor units, and, optionally, proximal portions (e.g. torso portions) of the arms are passed through an over-tube  1206 . Optionally, over-tube  1206  is deformable and can be shaped according to the need, so as to position the arms at a selected location and/or orientation relative to the motor units. Optionally, over-tube  1206  is configured to remain in a fixed position following deformation. 
       FIG. 13  illustrate use of two systems in a multi-port surgery, according to some embodiments of the invention. 
     In the exemplary setup shown in  FIG. 13 , a first system  1300  comprises 3 surgical arms, for example including two arms  1302  comprising an end effecter  1304 , and a third  1308  arm carrying an additional tool, such as a camera  1306  (see the enlarged view). A second system  1310  comprises two surgical arms  1312 . In some embodiments, first system  1300  is positioned to operate through a first port to the body, for example through the vagina. In some embodiments, the second system  1310  is configured to operate through a second body port, for example through an umbilical port. 
       FIGS. 14A-14B  illustrate a coupling between motor units, according to some embodiments of the invention. 
       FIGS. 14A-14B  show, at a cross section, housings of two motor units  1400  and  1402  configured to be coupled to each other, according to some embodiments.  FIGS. 14C-14D  show an isometric view of the motor unit housings. 
     In some embodiments, the motor units are coupled to each other by an interference fit. Optionally, the interference fit coupling comprises one or more protrusions received within one or more respective recesses. In the exemplary configuration shown herein, a longitudinal face  1401  of motor unit  1400  comprises a protrusion  1404  which is configured to be received in a respective indentation  1406  of motor unit  1402 . In some embodiments, for example as shown in  FIG. 14D , protrusion  1404  and respective indentation  1406  extend along at least a portion of the length of the motor unit. 
     In some embodiments, a total volume of structural elements coupling between the motor units is relatively small, for example less than 10%, less than 15%, less than 25% or intermediate, larger or smaller percentage of a total volume of the assembled motor construct. 
     In some embodiments, a geometry of face  1401  is configured to resist shear forces, for example to prevent movement of the motor units with respect to each other once attached, for example movement along an axis perpendicular to the long axis of the motor construct (e.g. movement of a motor unit upwards or downwards with respect to the adjacent motor unit). 
     In some embodiments, motor unit  1400  is configured to be slidably received in motor unit  1402 . Optionally, attachment of the motor units comprises moving (e.g. sliding) one motor unit with respect to another, for example sliding motor unit  1400  in a distal direction with respect to motor unit  1402 . Additionally or alternatively, attachment of the units comprises placing one motor unit over another. 
     In some embodiments, a coupling between the motor units is asymmetric. When the surgical arms are coupled to the motor units, a potential advantage of an asymmetric coupling may include approximating the arms to each other, by bringing the motor units closer together. Potentially, by holding the arms close together, a smaller (e.g. narrower) port can be used for accessing the patient&#39;s body. Alternatively, a coupling between the motor units is symmetrical. 
     In some embodiments, the motor units are configured to lock to each other once connected, for example via a plunger lock  1412  (see  FIG. 14C ). Optionally, the plunger lock is configured at a distal end of a groove  1414  (see  FIG. 14D ) in which a respective protrusion on the housing of motor unit  1402  is slidably received. 
     In some embodiments, the locking is released, for example by releasing a latch configured on the motor unit housing. (It is noted that the housings presented in these figures are shown without the motors and the actuation mechanisms. In some embodiments, a motor is positioned, for example, at cavity  1408 ). 
       FIGS. 15A-15E  are views of various arrangements of a coupling between gears of the motor unit and an extension of the surgical arm, and a coupling between a motor construct (e.g. comprising more than one motor unit) and a plurality of extensions of surgical arms, according to some embodiments. 
       FIG. 15A  shows two motor gears  1500  and  1502  of a motor unit (housing not shown), coupled to a gear  1504  of an extension  1506  of a surgical arm (e.g. bending gear and/or rotation gear for example as described hereinabove), according to some embodiments. 
     In  FIG. 15B , two motor units are aligned side by side, defining a motor construct according to some embodiments. Optionally, the motor gears of the two units are symmetrically arranged with respect to each other and/or with respect to a central long axis of the assembled motor construct. In some embodiments, extensions  1506  of two respective surgical arms are positioned adjacent each other. Optionally, extensions  1506  extend along the central long axis  1510  of the construct, opposing each other (e.g. a first extension positioned on one side (e.g. left of) the long axis, the second extension positioned on other side (e.g. right of) the long axis). In some embodiments, extensions  1506  are received in the motor construct from the top, e.g. insertion of the extensions is performed in the direction of arrows  1508 . Additionally or alternatively, insertion is performed by sliding the extension into the motor unit, for example in a distal to proximal direction along the long axis of the motor unit. 
     In  FIG. 15C , 3 motor units are arranged together to form a substantially circular motor construct, according to some embodiments. Optionally, extensions of 3 surgical arms are positioned about the central long axis  1510  of the motor construct, for example forming a triangular configuration. Optionally, insertion of the extensions to the motor construct comprises loading the extensions to the motor construct, for example by sliding the extensions in a distal to proximal direction into predefined channels or a central lumen of the construct. A configuration for example as shown in  FIG. 15C  may be especially advantageous for use in a single port operation in which 3 surgical arms are used. Optionally, the three surgical arms are held closely to each other by the motor construct so that the arms can be introduced together into the port to perform the operation. 
       FIG. 15D  shows a quadruple arrangement of motor units, according to some embodiments. In this example, 4 extensions are positioned to produce a squared arrangement about the central long axis  1510  of the motor construct. A configuration as shown in  FIG. 15D  may include 4 separate motor units coupled together, or, for example, two motor constructs (each comprising two pre-coupled motor units) arranged together. 
     In some embodiments, a motor unit housing includes four longitudinal faces e.g. in some embodiments a motor unit housing has a parallelogram cross section, at least for a portion of a longitudinal length of the motor unit. For example, referring to  FIG. 8A , in some embodiments, a motor unit, e.g. motor units  804  and  806 , has four longitudinal faces, where a cross section of tangential planes of the longitudinal faces is rectangular. For example, where an angle at an intersection between two longitudinal faces is about 90° (e.g. angles at each intersection between longitudinal faces is about 90°). 
     In some embodiments, a portion of the motor unit housing has a different shape, for example, in  FIG. 8A  the motor unit tapers towards a proximal end of the motor unit, a top longitudinal face of the motor unit bends towards a central long axis of the motor unit towards a proximal end of the motor unit. 
     In some embodiments, a motor unit housing includes two or three longitudinal faces where intersections between the faces are about perpendicular. In some embodiments, a face is shaped including protrusions and/or indentations and/or curves, e.g. in  FIGS. 9A-9B  undersides of the motor unit housings have a step shaped cross section. 
     In some embodiments, a motor unit housing has a shape where one or more intersection between longitudinal face planes is at a non-perpendicular angle. Potential benefits include the ability to position an arm closer to one or more longitudinal face of a motor unit housing and/or the ability to place a plurality of surgical arms extending from motor units close to each other. Referring to  FIG. 15C , in some embodiments, a motor unit has a housing cross section  1520  as illustrated by dashed lines. An angle of intersection between a first  1522  and a second  1524  longitudinal face is more than 90°, for example, 90°-140°, or lower or higher or intermediate angles or ranges. 
     In some embodiments, one or more intersection between longitudinal face planes is less than 90°, or 20°-89°, or 30°-80°, or lower or higher or intermediate angles or ranges. 
     In some embodiments, a number of arms to be inserted into a single port is selected, then a motor unit and/or motor unit housing is selected, where an intersection between longitudinal faces is related to the number of housings to be connected, for example, where, in come embodiments, the angle is 360° divided by the number of motor units. 
       FIG. 15E  illustrates a cross section of a motor construct including eight motor units and associated arm gears  1516  (motor gears not illustrated) where an angle α between longitudinal faces of the motor unit housings is about 360/8=45°. 
       FIG. 16A  is a simplified schematic of a surgical arm  1602  including surgical arm gears  1670  and a housing of a motor unit  1666 , according to some embodiments of the invention. Gears of the motor unit are not illustrated. 
       FIG. 16B  is a simplified schematic top view of a motor unit  1600  where a motor unit housing  1666  includes a plurality of anchors  1654   a - d , according to some embodiments of the invention. 
     In some embodiments, a motor unit housing has more than one anchor  1654   a - d . In some embodiments a motor unit housing has an anchor on more than one longitudinal face, for example, on each longitudinal face e.g. as illustrated in  FIG. 16B  where each of four longitudinal faces  1606   a - d  includes an anchor. 
     In some embodiments, anchors include indentation/s and/or protrusion/s configured to (e.g. sized and/or shaped to) connect with another anchor for example located on another motor unit housing. In some embodiments, anchors include indentation/s and/or protrusion/s configured to connect with a connector. 
     In some embodiments, a motor unit connector is configured for attachment (e.g. slide attachment) to more than one motor unit housing, for example, 2, 3, 4, 6 or larger or intermediate numbers of motor housings. 
     In some embodiments, a motor unit housing has rotational symmetry, for example, about a central long axis of the motor unit housing. 
     In an exemplary embodiment, a single connector is configured to connect two motor unit housings.  FIG. 17  is a simplified schematic top view of a motor unit connector  1756 , according to some embodiments of the invention. In some embodiments, connector  1756  is configured to connect two motor housings, for example, two of housing  1666  illustrated in  FIG. 16B . In some embodiments, connector  1756  connects two housings of different size and/or geometry. In some embodiments, connector  1756  connects a motor unit housing to another component, for example, a support (e.g. support  282   FIG. 2A , support  382   FIG. 3A ). 
     In some embodiments, a connector has symmetrical cross section with at least one axis of symmetry. A potential benefit of symmetrical cross section connectors and/or anchors is the ability to use a single connector to connect any two anchors. A further potential benefit is ease of connection where a connection does not involve matching a particular side of a connector to each anchor. In some embodiments, a connector, when connecting a plurality of anchors, has an axis (or axes if the plurality is more than two anchors) of symmetry at the connection axis (or axes). For example, connector  1756  has a cross section with two axes of symmetry. 
     In some embodiments, a connector has a shape including curved portions  1758 ,  1760 . A potential benefit of a curved connector is increased surface area between the connector and the anchor, potentially increasing the strength of friction between the anchor and the connector. 
       FIG. 18  is a flow chart of a method of connecting a plurality of motor unit housings, according to some embodiments of the invention. 
     At  1800  a plurality of motor unit housings, each housing having at least one anchor, are positioned such that at least two anchors, each anchor on a different housing are facing each other. Although description of this method (and the method of  FIG. 19  and in other parts of this document) is with respect to motor unit housings, it is to be understood that this method (and/or connection of motor units as described elsewhere in the document) also refers to interconnection of one or more motor unit with one or more other component including an anchor where the component is not necessarily a motor unit housing. For example, in some embodiments, a connector connects a motor unit housing to another component, for example, a support (e.g. support  282   FIG. 2A , support  382   FIG. 3A ). 
     At  1802 , a connector is, for example, inserted, connecting two or more housings. For example, in some embodiments, connector  1756  connects two housings by slide attachment, for example, in some embodiments, the motor housings are placed and/or held together such that two anchors, one on each housing are adjacent such that connector  1756  is slid into the hollow formed by the two anchors. 
     At  1804 , optionally, in some embodiments, an additional connector is attached to and/or inserted into a plurality of housings. For example, referring to  FIG. 20B , in some embodiments, all four motor units  2004   a - d  are positioned together and then connectors  2056   a - d  are inserted. 
     At  1806 , optionally, in some embodiments, additional housing/s are positioned and then, optionally, at  1802  an additional connector is attached. 
       FIG. 19  is a flowchart of a method of connecting a plurality of motor unit housings, according to some embodiments of the invention. 
     At  1900 , in some embodiments, a connector is attached (e.g. slid into) a first anchor on a first motor unit. 
     At  1902 , optionally, in some embodiments, additional connector/s are attached to the first anchor and/or to different anchor/s on the first motor unit. 
     At  1904 , in some embodiments, a connector (while attached to the first motor unit) is attached (e.g. slid) into a second anchor on a second motor unit, or the anchor of the second motor unit is attached (e.g. slid) onto connector. Optionally, in some embodiments, additional motor units, for example, a third motor unit, are attached. 
       FIG. 20A  is a simplified schematic of a plurality of motor units  2004   a - d , associated surgical arms  2002   a - d  and a plurality of connectors  2056   a - d  prior to connection, according to some embodiments of the invention. 
     In  FIG. 20A  length of connectors  2056   a - d , e.g. with respect to length of motor units  2004   a - c  is visible. In some embodiments, connectors and/or anchors have constant cross section (where cross section is taken perpendicularly to a long axis of the connector). For example, connectors  2056   a - d  in  FIG. 20A  have constant cross section. 
     Alternatively, in some embodiments, a connector and/or anchor has varying cross section. For example, in some embodiments, a connector tapers along a long axis length. For example, in some embodiments, a connector has one or protrusion and/or hollow along a long axis length (e.g. the protrusion and/or hollow providing an interference fit with an anchor e.g. the hollow providing an anchor for an anchor locking element e.g. spring loaded locking element). In some embodiments, a plurality of connectors connecting a plurality of motor housings has different shape and/or dimensions. 
     In some embodiments, motor housings and connectors have different long axis lengths. For example, referring to  FIG. 20A , in some embodiments, a connector  2056  has a length L 1  which is shorter than a length of one or more of the motor housing/s which the connector connects e.g. L 1 &lt;L 2  where L 2  is a length of the motor housing of motor unit  2004   c . For example, in some embodiments, a connector is short in length with respect to housings (e.g. with a long axis length of less than 70% or less than 50%, or less than 30% or less than 20% or less than 10% or less than 5% or 1-50%, or 1-20% or higher or lower or intermediate percentages of a length of a motor unit housing to which the connector is connected). Alternatively, in some embodiments, one or more connector is longer than one or more housing. 
     In some embodiments, a plurality of connectors connect a first anchor on a first housing and a second anchor on a second housing. For example, in some embodiments, a plurality of connectors are used when connectors are small in size and/or length with respect to a housing and/or housing weights. 
     In some embodiments, one or more connector is, for example, a snap-fit connector, a snap fastener. 
     In some embodiments, a connector surrounds at least a portion of one or more motor unit. For example, in some embodiments, a connector is a jacket or sleeve sized and/or shaped to accept and hold together in close proximity two or more motor units. 
     In some embodiments, a connector sleeve is made of rigid material. In some embodiments, a connector sleeve is made of flexible material optionally incorporating rigid element/s. 
     In some embodiments, use of a particular connector is used to provide information as to an arrangement of motor units. For example, in some embodiments, one or more connector includes a sensor (e.g. electromagnetic lock) which detects proximity of motor unit/s, the sensor providing information as to the spatial arrangement of motor units and/or surgical arms to the surgical system (e.g. to a processor). In some embodiments, use of a sleeve connector, for example, a rigid sleeve connector, means that a spatial arrangement of the motors is defined by the sleeve. For example, in some embodiments, a user selects a motor unit configuration and/or a suitable sleeve connector and enters this information and/or selects a matching model at a user interface. 
       FIG. 30  is a simplified schematic of a surgical system  3000 , according to some embodiments of the invention. In some embodiments, system  3000  includes a plurality of modular units, each modular unit including a surgical arms  3002 ,  3004  configured to be attached to a motor unit  3006 ,  3008 . In some embodiments, a memory  3012  stores one or more model of a configuration of attachment of modular units. In some embodiments, a user selects the model, for example, through a user interface  3010 . Where, for example, a processor  3014  receives a user selection from user interface  3010 , sending it for storage in memory  3012 . 
     Alternatively or additionally, in some embodiments, one or more sensor, for example, located on a motor unit and/or surgical arm, sends a signal related to an attachment configuration to processor  3014  which is then sent by processor  3014  to be stored in memory  3012 . It is to be understood that, in some embodiments, the system includes more than one user interface and/or more than one processor and/or more than one memory. 
     In some embodiments, processor  3014  uses the model and/or a controller uses the model in generation of control signals, which, for example, control movement of surgical arms  3002 ,  3004 . For example, using the model to prevent collision of surgical arms during movement of the surgical arms. 
     In some embodiments, a memory stores information related to recommended configurations of modular units associated with different procedures. For example, in some embodiments, memory  3012  includes a look-up table of recommended modular unit configuration with surgical procedure, and/or with features of a surgical procedure (e.g. number of ports, position of ports, type of port). 
       FIG. 20B  is a simplified schematic top view of a motor construct  2014  including a plurality of motor units  2004   a - d  connected by connectors  2056   a  in a square configuration, according to some embodiments of the invention. Motor gears of the motor units are not illustrated in  FIG. 20B . 
     In some embodiments,  FIG. 20B  illustrates a top view of the motor units and connectors illustrated in  FIG. 20A , after attachment of the motor units  2004   a - d  by connectors  2056   a - d.    
     In some embodiments, a closely packed arrangement of motor units (e.g. spare, circular) is selected, for example, for insertion into a round incision and/or a linear incision stretched into a round entrance into a patient body. For example, in some embodiments, an aspect ratio of the cross section area of the motor unit construct is 1:1-1:4 or 1:1-1:2, or lower or higher or intermediate ranges or aspect ratios. 
     In some embodiments, an elongated arrangement of motor units is selected, for example, for insertion into an elongated incision (for example, through port  514  illustrated in  FIG. 5B ) and/or for a surgical path with a body which is narrow and/or elongated (e.g. to surgical arms passing through a space between adjacent ribs). In some embodiments, an aspect ratio of the cross section of the motor unit construct is 1:1.5-1:10, or 1:2-1:4, or lower or higher or intermediate ranges or aspect ratios. 
       FIG. 21  is a simplified schematic of a plurality of motor units  2104  connected in an elongated configuration, according to some embodiments of the invention. In some embodiments, an elongated configuration includes a single row of attached motor units e.g. as illustrated in  FIG. 21 . 
     In some embodiments, selection of a spatial configuration of connected motor units includes selection of axial position of the motor units. In some embodiments, axial position motor units affects axial position of surgical arm/s and/or surgical arm tools. In some embodiments, axial position of surgical arm/s and/or arm tools is selected and then axial position of motor units is defined by this selection. 
     In some embodiments, motors units are attached to each other such that the motor units have different axial positons with respect to each other. 
       FIG. 22A  is a simplified schematic of a plurality of connected motor units  2204   a - d , and associated surgical arms, where one of the motor units has a different axial position, according to some embodiments of the invention. 
       FIG. 22B  is an enlarged view of the portion of the motor units illustrated in  FIG. 22A , according to some embodiments of the invention.  FIG. 22B  shows an enlarged view of the portion in  FIG. 22A  indicated by an “X”. 
     In  FIGS. 22A-22B  motor unit  2204   b  is axially displaced with respect to motor units  2204   a ,  2204   c ,  2204   d  and, as a combined length of each surgical arm and motor unit is about equal, a maximum reach of a surgical arm  2202   b  associated with motor unit  2204   b , when the arm is in a straight configuration, is larger than that of the other surgical arms associated with motor construct of attached motor units  2204   a - d.    
     In some embodiments, more than one set of motor units (e.g. motor construct) each having a different surgical approach is used. For example, for a single procedure, more than one surgical approach is selected. In some embodiments, more than one surgical approach is implemented simultaneously. For example, where more than one of ports  512  illustrated in  FIG. 5B  are used. Alternatively, or additionally, in some embodiments, more than one surgical approach is implemented sequentially. 
       FIG. 23  is a simplified schematic of system including a first plurality of surgical arms  2300  inserted into a first port  2308  and a second plurality of surgical arms inserted into a second port  2310 , according to some embodiments of the invention. In some embodiments, the first plurality of surgical arms  2300  and the second plurality of surgical arms  2302  are associated with a first motor construct  2304  and a second motor construct  2306  respectively. 
     In some embodiments, both pluralities of arms access a surgical target area  2312 , for example, through different ports and/or through different surgical paths. 
     Alternatively, in some embodiments, a first and a second plurality of coupled surgical arms are inserted through a single port. In some embodiments, a spatial configuration of each motor construct has been selected for compatibility with the respective associated surgical approach. 
     In some embodiments, each surgical modular unit including a surgical arm and an associated motor unit is controlled by a modular control unit. In some embodiments, a surgical system is configured such that there is a separate control unit for each modular unit. Alternatively, in some embodiments, a control unit is used to control more than one surgical modular unit. In some embodiments, control units are connected in a configuration matching that of connected modular units. 
     In some embodiments, first plurality of surgical arms  2300  is controlled by a first plurality of control modules  2314  and second plurality of surgical arms  2302  are controlled by a second plurality of control modules  2316 . 
     In some embodiments, a single control module is used to control a single surgical arm. In some embodiments, more than one surgical arm is controlled by a single control module, for example, sequentially. 
     In some embodiments, a plurality of control modules are configured to interlock with each other, for example using mechanical means such as slide attachment, plunger lock, pins and/or other fasteners. In some embodiments, control modules interlock with each other using electromagnetic means. In some embodiments, interlocking between the control modules is released by a quick release mechanism, for example comprising a latch movable for releasing the lock. In some embodiments, one or more connector is used to connect two or more control modules, for example, a connector connecting two anchors one anchor located on each of two control module housings. In some embodiments, an anchor includes one or more indentation and/or protrusion. In an exemplary embodiment, an anchor is an indentation sized and shaped to receive a portion of a connector. In some embodiments, control modules are coupled by placing the control modules into a housing (e.g. a sleeve, a stand, a control console) which is configured to accept a plurality of control modules. 
     In some embodiments, the first and second plurality of surgical arms are controlled simultaneously, for example, by a single user e.g. in some embodiments, control modules  2314  and  2316  are both controlled by a single user. Alternatively, in some embodiments, the first and second plurality of surgical arms are controlled by more than one user. For example, in some embodiments, control modules  2314  are controlled by a first user and control modules  2316  are used by a second user. 
     In some embodiments, one or more control module (e.g. each control module) includes an input device arm  2320  coupled to a support  2318 . In some embodiments, one or more control module support is configured to be coupled to another control module support. 
     In some embodiments, a surgical system is as described and/or includes control and/or input devices, for example, as described in U.S. patent application Ser. No. 15/418,891, which is incorporated herein by reference in its entirety. 
     In some embodiments, a surgical arm and an input device arm both include a sequential structure of connected portions where movement of one or more portion of the input device arm controls movement of a sequentially corresponding portion of the surgical arm. For example, in some embodiments, input device arm joints correspond to flexible portions of a surgical device e.g. each input device joint corresponds to a single flexible portion of a surgical device. 
     In some embodiments, a ratio between effective segment lengths of an input device segment pair (e.g. two adjacent input device segments) is substantially the same as an effective segment length ratio between a corresponding surgical device segment pair. 
     In some embodiments, each driven portion of the surgical device has a corresponding portion of the input device. In some embodiments, a surgical device arm and an input device arm both include segments coupled by connecting portions. In some embodiments, an input device arm includes at least the number of joints and/or segments as a corresponding articulated surgical device arm. In some embodiments, the input device and the surgical device include the same number of segments and/or the same number of connecting portions. 
     In some embodiments, one or more portion of an input device has the same degrees of freedom as that of a corresponding portion of a surgical device. For example, in some embodiments, input device portion/s are bendable by about the same amount as corresponding surgical device portions. For example, surgical device portion/s which are rotatable around the surgical device portion long axis correspond to input device portions which are rotatable around the input device portion long axis. 
     Potentially, similar structure of the input device arm and surgical device arm provides intuitive control of the surgical device. 
     In some embodiments, a sequential structure of the input device and/or the surgical device includes segments (e.g. rigid portions) connected by connecting portions (e.g. pivot joints and/or flexible sections). In some embodiments, an input device arm includes segments sequentially coupled by joints. In some embodiments, a surgical device arm includes sequentially coupled flexible portions, optionally coupled by surgical device segments. In some embodiments, freedom of movement of input device segments about joints is about the same as freedom of movement of corresponding surgical device flexible portions. For example, in some embodiments, a flexible surgical device portion is bendable by the same angle as an angle between two input device segments coupled by a joint corresponding to the flexible surgical device portion. 
     In some embodiments, an angle between long axes of input device segments coupled by a joint controls an angle of a corresponding surgical device flexible portion. Where, for example, an angle of the surgical device flexible portion is defined between long axis tangents of the flexible portion at the flexible portion ends. Where, for example, an angle of the surgical device flexible portion is defined as an angle between effective segment long axis (e.g. where effective segment axes are described herein). 
     In an exemplary embodiment, an input device includes a more angular shape and/or a shape with a larger relative lateral extent than that of the surgical device. For example, in an exemplary embodiment, input device connecting portions are pivot connections between rigid segments, whereas surgical device connecting portions are long bendable sections. In some embodiments, pivot points connecting sections of the input device are not disposed at an intersection between effective input device limbs for example, potentially reducing a difference between input device and surgical device structures. 
     In some embodiments, an angle between an input device radius and an input device humerus controls an angle between a surgical device radius and a surgical device humerus where a ratio between effective lengths of the input device radius and humerus is substantially the same as a ratio between effective lengths of the surgical device radius and humerus. 
     In some embodiments, a user manually moves portion/s of the input device to control movement of the surgical device. In some embodiments, a user controls position of more than one part of the device simultaneously, for example, using one hand. In some embodiments, the input device includes two limbs (also herein termed “arms”), and a user controls each limb with one hand. 
     In some embodiments, an angle between long axes of two adjacent input device segments controls an angle between long axes of two corresponding adjacent surgical device segments. In some embodiments, a rotation of one or more input device segment controls rotation of a corresponding surgical device segment. 
       FIG. 24A  is a simplified schematic side view of an input device arm  4804   ip , according to some embodiments of the invention.  FIG. 24B  is a simplified schematic side view of a surgical device arm  4804 , according to some embodiments of the invention. In some embodiments, input device arm  4804   ip  controls surgical device arm  4804 . 
     In some embodiments, an input device structure has one or more ratio and/or dimension which is substantially the same as (also herein termed “matching”) a ratio and/or dimension (optionally scaled) of a surgical device and, optionally, one or more other dimension and/or ratio which does not match those of a surgical device. 
     For example, in an exemplary embodiment, a length ratio between two effective segment lengths of an input device and a surgical device are substantially the same, for example, with 0-5%, or 0-1%, or 0-0.5%, or lower or higher or intermediate ranges or values of a difference between the ratios. 
     Where an effective segment length is the length of a central long axis of the segment between intersections of long axes of other segments and/or between an axis intersection and a termination of the segment. 
     For example, referring to  FIG. 24A : An effective length of an input device arm  4800   ip  humerus  4812   ip  is length Hip, measured between intersections of humerus long axis  4813   ip  with the support (e.g. support long axis  4803   ip ) and radius long axis  4817   ip . An effective length of an input device arm  4800   ip  radius  4816   ip  is length Rip, measured between intersection of radius long axis  4817   ip  and termination of input device radius  4816   ip.    
     Potentially, an effective input device radius length corresponding to an effective surgical device radius length which does not include a length of an end effecter means that accuracy of control is maintained for surgical devices with different end effecters (e.g. different sized end effecters). 
     In some embodiments, referring now to  FIG. 24E , effective segments are straight lines connecting a center point of flexible portions (e.g. for surgical device arms) and/or joints (e.g. for input device arms). Where, for example, an effective radius of input device  2404   ip  is a straight line connecting pivot point of joint  2420   ip  to a distal end of radius  2416   ip  (distal end terminating in connection to handle  2418   ip ). Where, for example, an effective humerus of input device  2404   ip  is a straight line connecting centers of pivot joints  2408   ip  and  2420   ip . Where, for example, referring to  FIG. 1C , an effective surgical arm humerus is a line connecting a midpoint of flexible portion  108  to a midpoint of flexible portion  120  and an effective surgical arm radius is a line connecting a midpoint of flexible portion  120  to a distal end of radius  116 . 
     In some embodiments, one or more matching segment length ratio between an input device and a surgical device enables intuitive control of the surgical device with the input device, for example, despite structural differences between the devices. For example in some embodiments, a surgical device (e.g. as described elsewhere in this document) includes long connecting portions, whereas, in some embodiments, (e.g. as illustrated in  FIG. 24A ) input device arm joints include pivots. 
     In some embodiments, effective segment length ratios between the input device and surgical device match, but actual segment length ratios do not match. For example, in some embodiments, a surgical device includes long connecting portions (e.g. as described in the section of this document entitled “Exemplary long joints”), and an input device capable of controlling the surgical device includes short connecting portions for example, pivot connections (e.g. as illustrated in  FIG. 24A ). Potentially, an advantage being ease of control of the input device (e.g. input device segments rotate freely about pivots, e.g. input device segments do not move with unwanted degrees of freedom from long joints) and/or a surgical device which has an non-angular shape (e.g. less likely to damage patient tissue). 
     In an exemplary embodiment, a thickness of one or more input device segment (e.g. diameter of cylindrical segments and/or largest segment cross sectional dimension) is different (e.g. larger) than to those of a surgical device. Increased input device segment thickness potentially provides space for sensors and/or locking devices and/or provides an input device with dimensions which are comfortable and/or easy for a user to maneuver. 
     In an exemplary embodiment, input device segment thickness is 20-26 cm, or 13-18 cm, or 13-26 cm, or lower, or higher or intermediate ranges or thicknesses. 
     In an exemplary embodiment, surgical device segment thickness is 6-8 mm, or 4-8 mm, or 4-6 mm or lower, or higher or intermediate ranges or thicknesses. In some embodiments, surgical device segment thickness is 0.1-5 mm, 0.5-3 mm, or 0.1-1 mm, or lower or higher or intermediate ranges or thicknesses. 
     In an exemplary embodiment, a ratio between surgical device segment thickness and input device segment thickness is 1:0.5, to 1:3, or lower, or higher or intermediate ranges or ratios. 
     In an exemplary embodiment, a ratio between surgical device segment length and input device segment length is 1:0.5, to 1:3, or lower, or higher or intermediate ranges or ratios. 
     In some embodiments, a measured angle and/or change in angle between long axes of two input device segments, is used to control and/or change an angle between corresponding long axes of two surgical device segments. 
     In some embodiments, measurement is of a physical angle (e.g. angle α) between long axes of two device segments and/or between effective segments (e.g. as described hereinabove). In some embodiments, measurement is of a change in angle between long axes of two device segments and/or between effective segments. 
     For example, in some embodiments, an angle α′ between a long axis  4813  of a surgical device humerus  4812  and a long axis  4803  of a surgical device support  4802  is controlled by an angle α between a long axis  4813   ip  of an input device humerus  4812   ip  and a long axis  4803   ip  of an input device support  4802   ip.    
     For example, in some embodiments, an angle ( 3 ′ between a long axis  4817  of a surgical device radius  4816  and a long axis  4813  of a surgical device humerus  4812  is controlled by an angle β between a long axis  4817   ip  of an input device radius  4816   ip  and a long axis  4813   ip  of an input device humerus  4812   ip.    
     In an exemplary embodiment, a surgical device is controlled using a one-to-one mapping of an angle between adjacent input device segments and corresponding adjacent surgical device segments. 
     In some embodiments, rotation of an input device segment about a long axis of the segment is used to control rotation of a corresponding surgical device segment. 
     In some embodiments, measurement is of a physical angle of rotation. In some embodiments, measurement is of a change in angle of rotation. 
       FIG. 24D  is a simplified schematic view of a control console, according to some embodiments of the invention. In some embodiments, a system including surgical arm/s and motor unit/s includes a control console for control of the surgical arms. In some embodiments, a user controls movement of surgical arms using a control console. In some embodiments, upon actions of a user, the control console sends signal/s (e.g. via processor/s) to instructing motor gears in motor unit/s. In some embodiments, a control console includes one or more input device arms. In an exemplary embodiments, the control console includes two input arms  2404   ip ,  2406   ip . In some embodiments, two input arms are used to control one, two, or more than two surgical arms, for example, more than one surgical arm construct. Where, for example, a user selects surgical arms for control with the surgical arms, for example, then changing and/or switching the surgical arm selection. 
     In some embodiments, the control console includes a seat  2440  for a user to sit on and/or one or more arm support  2438 . In some embodiments, position of seat  2440  and/or arm supports  2438  is adjustable. In some embodiments, the control console is mobile, for example, may be moved around (e.g. within an operating theatre). For example, in some embodiments, the control console is sized and/or shaped for ease of movement e.g. has less than 3×2 meter, or 2×1 meter, or lower or higher or intermediate ranges or areas footprint e.g. weighs less than 20-100 kg, or 60-80 kg, or about 72 kg or lower or higher or intermediate weights or ranges. In some embodiments, the control console includes one or more wheel  2442  mounted to a base of the control console and configured for wheeling the control console. 
     In some embodiments, the control console includes a display  2438 , for example, for display of imaging during surgery (e.g. from a camera inserted with and/or mounted on surgical arm/s). Optionally, display  2438  is a touch screen and acts as a user interface. In some embodiments, the console includes additional user interface/s, for example, in some embodiments including an on/off switch and light indicator  2426  and and/or an emergency switch off button  2444 , and/or user interface/s on the input arm/s  2404   ip ,  2406   ip.    
       FIG. 24E  is a simplified schematic side view of an input device arm  2404   ip , according to some embodiments of the invention. In some embodiments, input arm  2404   ip  includes a support segment  2402 , a first input joint (also termed input device shoulder joint)  2408   ip , a first input segment (also termed input device humerus)  2412   ip , a second input joint (also termed input device elbow joint)  2420   ip  and a second input segment (also termed input device radius  2416   ip ). In some embodiments, joints  2408   ip ,  2420   ip  are pivot joints, which, in some embodiments, are separably bendable. 
     In some embodiments, an orientation of segments with respect to each other is adjusted by rotation of a segment and/or by rotation of a portion of a segment with respect to another portion of a segment. 
     For example, in some embodiments, second portion  2450   ip  of first input segment  2412   ip  is rotatable above a first input segment long axis, where rotation is with respect to a first portion  2452   ip . The rotation is, for example illustrated by the arrow A in  FIG. 24E . 
     For example, in some embodiments, support segment  2402  is rotatably attached to an input arm support  2438   ip . For example, in some embodiments, a handle  2418   ip  is rotatable with respect to second segment  2416   ip.    
     In some embodiments, input arm support  2438   ip  is pivotally connected to a stand  2436   ip , rotation of the arm about the pivot connection thereby allowing a user to change an orientation of input device arm  2404   ip  with respect to stand  2436   ip . In some embodiments, button  2432   ip , controls the ability to pivotally rotate the arm about the pivot connection, for example, in some embodiments, pressing on the button enables rotation. 
     In some embodiments, a user grasps handle  2418   ip , for example, inserting a finger (e.g. index finger) into loop  2420   ip . In some embodiments, while grasping handle  2428   ip , a user interacts with user interface/s mounted on handle  2428   ip . For example, buttons  2424   ip  and lever  2422   ip.    
     In some embodiments, the input device user interface/s are used to control the surgical arm, e.g. actuation of an arm tool e.g. opening and/or closing of a gripper. 
     Alternatively or additionally, in some embodiments, input device user interface/s are used to control other portions of the system, for example, the display of the control console (e.g. display  2438   FIG. 24D ). 
     In some embodiments, input device and/or control console user interfaces control linear movement of the surgical arm (e.g. into and/or out of a patient) and/or pausing and/or resuming of control of movement of the surgical arm by the input arm. 
     In an exemplary embodiment, a first of buttons  2424   ip  controls forward linear movement, a second of buttons  2424   ip  controls backwards linear movement and a third of buttons controls pausing and resuming of control of movement of the surgical arm by the input arm. 
     In some embodiments, lever  2422   ip  controls a surgical arm tool, for example controls opening and/or closing of a grasper tool (e.g.  124   FIG. 1C ). 
     In some embodiments,  2428   ip  and  2430   ip  are connectors (in an exemplary embodiment, connectors  2428   ip ,  2430   ip  are bolts) which, when removed, provide access to connection of the input arm to stand  2436   ip  e.g. for removal and/or replacement of the input arm from the stand. 
     In some embodiments,  2426   ip  is an element which enables rotation of stand  2436   ip  about a stand long axis, enabling a user to change the orientation of the input device arm with respect to the control console. 
     In some embodiments, one or more control module includes one or more sensor which is configured to detect whether the control module has been connected to one or more other control module and/or a coupling arrangement of control modules. In some embodiments, a sensor detects insertion and/or attachment of a control module onto a control console. In some embodiments, each a control module (e.g. each control module) includes a sensor which senses whether the control module is attached to another control module and/or an attachment configuration. In some embodiments, a control module sensor provides a signal including attachment information (e.g. if the control module is attached and/or an attachment configuration) to a processor, for example, a control processor e.g. located at a control console. 
     In some embodiments, a control console (e.g. providing location for attachment of a plurality of control modules) includes sensor/s sensing attachment and/or an attachment configuration of control modules. 
     In some embodiments, a processor (e.g. located at a control console) receives attachment information of surgical motor modules. In some embodiments, one or more motor unit includes a sensor configured to detect whether the motor unit has been connected to one or more other motor units and/or an attachment configuration of the motor units. 
     In some embodiments, a motor unit includes a plurality of motor gears where each motor gear is coupled to a gear of an extension of a surgical arm, also herein termed “surgical arm gear” or “arm gear”. Surgical arm gears include, for example, bending gears and/or rotation gears, e.g. as described with reference to  FIG. 6B . 
     In some embodiments, an axis of arm gears is positioned adjacent to one or more longitudinal face of a motor unit, with motor gear/s positioned adjacent to the arm gears. A potential benefit being the ability to place the surgical arm close to the longitudinal face (e.g. enabling a plurality of arms to be placed closely together). In some embodiments, size and/or axial positioning of motor gear/s restricts a minimum size of the motor unit thereby, in some embodiments, meaning that, for surgical arms to have a small separation, motor units may only be connected to each other at particular longitudinal faces. 
     In some embodiments, motor gears surround the surgical arm gears. For example, referring to  FIG. 16B , in some embodiments, housing  1666  includes four axial locations surrounding surgical arm gear  1670  and configured to accept motor gears: In the top view of  FIG. 16B  motor gear  1662   a  which drives surgical arm gear  1670  is visible in one of the locations, and housing  1666  includes a further three locations  1664   a ,  1664   b  and  1664   c  configured for housing motor gears positioned to drive surgical arm gear  1670  or other surgical arm gears which are not visible in  FIG. 16B . 
     In some embodiments, a lateral distance between an arm and a longitudinal face of a motor unit to which the arm is coupled, e.g. distance  803  in  FIG. 8B , is restricted by a size of gears of the surgical arm (e.g. bending and/or rotation gears) and/or a size and location of motor gears driving the gears of a surgical arm (gears e.g. as described in more detail with reference to  FIG. 6B ). 
     In some embodiments, one or more surgical arm gear is smaller in diameter than a motor gear driving the surgical arm gear, e.g. as illustrated in  FIGS. 15A-15D . A potential benefit being higher torque (e.g. than that of a gear with the same or smaller diameter as the surgical arm gear) of the driving gear on the surgical gear and/or a lower speed of rotation of the driving gear to effect a desired rotation speed of the surgical arm gear. In some embodiments, one or more motor gear has the same diameter (e.g. as illustrated in  FIGS. 25-26 ) or smaller diameter as a surgical arm gear which it is driving. 
     In some embodiments, e.g. as illustrated by  FIG. 16A , all surgical arm gears  1670  have about the same diameter. Alternatively, in some embodiments, one or more surgical arms gear has a different diameter. Similarly, in some embodiments, all motor gears have about the same diameter. Alternatively, in some embodiments, one or more motor gear has a different diameter. 
     In some embodiments, each arm gear is driven by a single motor gear. 
     Alternatively, in some embodiments, one or more arm gear is driven by more than one motor gear. For example, referring to  FIG. 16B , where arm gear  1670  is driven by motor gear  1662   a  and an additional motor gear housed in one of gear locations  1664   a - c . A potential advantage of driving an arm gear with more than one motor gear is the ability to achieve a certain torque with smaller gears. 
     In some embodiments, a motor unit includes motor gears with different axes.  FIG. 25  is a simplified schematic of arm gears A 1 - 6  and motor gears M 1 - 6  within a motor unit housing  2500 , according to some embodiments of the invention. In some embodiments,  FIG. 25  illustrates the motor unit embodiment illustrated in  FIG. 6B  where motor gears M 1 , M 3  and M 5  are aligned axially and where motor gears M 2 , M 4  and M 6  are aligned axially in a different axial position and where surgical arm gears A 1 - 6  are aligned axially. Where axial alignment is when central axes of the gears about which the gears rotate are collinear. An advantage of having motor gears in different axial positions is reduction of length L 1  of the motor unit and/or separation between arm gears A 1 - 6 , when motors are collinear with the driving gears (e.g. as illustrated in  FIG. 6B ). 
     In some embodiments, a motor unit has motor gears where all of the gears have the same axis.  FIG. 26  is a simplified schematic of arm gears a 1 - 6  and motor gears m 1 - 6  within a motor unit housing  2600 , according to some embodiments of the invention. In some embodiments, all of the motor gears m 1 - 6  are aligned axially meaning that, for example, in some embodiments, the gears are enclosed in a smaller height H 2  motor unit housing  2600  e.g. H 2 &lt;H 1 . A potential benefit being a smaller distance between an surgical arm  2602  and longitudinal faces  2604 ,  2606  of motor housing  2600 . 
     In some embodiments, size of motor units and/or surgical arm gears does not restrict a minimum separation between surgical arms.  FIG. 27  is a simplified schematic of a first  2700  and a second  2702  surgical arm, the first arm including first surgical arm gears  2704  and the second arm including surgical arm gears  2706 , according to some embodiments of the invention. In some embodiments, surgical arm gears are positioned at different axial position (e.g. axially staggered). A potential benefit being the ability to place the arms close together. 
     In some embodiments, a motor unit is miniaturized sufficiently that one or more motor unit is inserted through a port into a body. For example, in some embodiments, the motor unit housing and/or motor gears and/or surgical arm gears are sufficiently small for insertion into a body, e.g. through a port. In some embodiments, a motor unit has a cross section where at least one dimension and, in some embodiments, all dimensions are at most 100%, or 70% or 0-70% or 0-50% or 0-20% larger than a cross sectional dimension (e.g. diameter) of the surgical arm abutting the motor unit. 
     The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”. 
     The term “consisting of” means “including and limited to”. 
     The term “consisting essentially of” means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure. 
     As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof. 
     Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. 
     Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. 
     As used herein the term “method” refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts. 
     As used herein, the term “treating” includes abrogating, substantially inhibiting, slowing or reversing the progression of a condition, substantially ameliorating clinical or aesthetical symptoms of a condition or substantially preventing the appearance of clinical or aesthetical symptoms of a condition. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements. 
     Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. 
     All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting. In addition, any priority document(s) of this application is/are hereby incorporated herein by reference in its/their entirety.