Homing of cable-driven surgical tools in surgical robotic systems

Abstract

To return a cable-driven instrument in a surgical robotic system to its position, any elongation of the cable is determined by applying pressure to the cable in a known configuration. The actuator position used for homing is then updated to account for any elongation. This provides more precise control and manipulation of the instrument during surgical procedures.

Description

[0001] Related applications This patent document claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 595,006, filed November 1, 2023, pursuant to 35 USC §119(e), which is hereby incorporated by reference. Technical Field

[0002] The implementation plan involves establishing in-situ or known configurations of cable-driven surgical tools for establishing surgical robotic systems. Background Technology

[0003] Minimally invasive surgery (MIS), such as laparoscopic surgery, involves techniques designed to reduce tissue damage during surgical procedures. MIS can be performed using robotic systems comprising one or more robotic arms that manipulate surgical instruments based on commands from a teleoperator. In robotic MIS systems, it may be desirable to establish and maintain high positional accuracy of surgical instruments supported by the robotic arms.

[0004] Surgical instruments for robotic arms can share similar designs; for example, a tool may have an end effector comprising a robotic wrist and one or more jaws. This end effector may include tools for grasping, cutting, suturing, and other surgical tasks. A cable system connects the end effector to actuators in a tool drive mechanism, which can drive multi-axis movements (e.g., pitch and yaw) of the end effector. For example, four actuators with four cables drive an end effector having a robotic wrist with a pair of jaws.

[0005] Ideally, knowing the actuator position where the cable has positive tension allows the angle of the joint (e.g., wrist or jaw) to be determined. When a device is placed on a robotic arm, it is important to know where the wrist joint originates. Factory homing stores actuator positions used to hom the device in a specific configuration, allowing the actuators to be driven to those positions to achieve homing. However, in reality, after each use cycle, the actuator's home position may change slightly due to factors such as plastic deformation of the cable and cleaning and sterilization of the device using specialized solutions. Therefore, factory homing can become inaccurate. Summary of the Invention

[0006] By way of introduction, the preferred embodiments described below include methods, systems, instructions, and computer-readable media for homing cable-driven instruments in a surgical robotic system. Starting from a previous homing, any amount of cable elongation is determined by applying pressure to the cable in a known configuration. The actuator position used for homing is then updated to account for any elongation. Therefore, more accurate control and manipulation of the instruments during surgical procedures is provided.

[0007] In a first aspect, a method is provided for homing a cable-driven instrument of a surgical robotic system. The cable-driven instrument engages with a tool actuator of a surgical robotic arm. After engagement, the motor of the tool actuator is positioned in a first calibrated position in the in-situ configuration of the cable-driven instrument. Tension is applied to the cable of the cable-driven instrument by the motor. Any slack in the cable of the cable-driven instrument in its in-situ configuration is removed. The first calibrated position of the motor is updated based on the position of the motor after tension is applied to the cable. The cable-driven instrument is controlled during surgery based on the updated first calibrated position.

[0008] In a second aspect, a surgical robotic system for homing is provided. A surgical tool is connected by a first number of cables to a corresponding number of actuators. The surgical tool is connected such that actuation of the actuators causes the surgical tool to move with a fewer number of degrees of freedom than the first number (e.g., four cables for controlling three degrees of freedom). A first sensor is configured to sense the force applied by the actuators. A processor is configured to control the actuators to apply pressure to the cables when the surgical actuators are not moving. The pressure is sensed by the first sensor. The processor is configured to use the pressure to determine the in-situ position of the actuators relative to the in-situ position of the surgical tool.

[0009] In a third aspect, a method is provided for homing a cable-driven instrument of a surgical robotic system. The cable-driven instrument is positioned in situ. Tension is applied to the cable of the cable-driven instrument in its situ position. The amount of cable elongation is determined based on the force on the cable and the position of an actuator that operates the cable-driven instrument in two or more configurations with known references. During surgery, the cable-driven instrument is operated under the control of the actuator, taking into account the amount of elongation.

[0010] This invention is defined by the following claims, and the content of this section should not be construed as limiting those claims. Other aspects and advantages of the invention are discussed below in conjunction with preferred embodiments, and may subsequently be claimed independently or in combination. Attached Figure Description

[0011] Embodiments of the invention are illustrated by way of example and not by way of limitation in the accompanying drawings, wherein similar reference numerals indicate similar elements. It should be noted that references to "an" or "one" embodiment of the invention in this disclosure do not necessarily refer to the same embodiment, and that they refer to at least one. Furthermore, for the sake of brevity and to reduce the total number of drawings, a given drawing may be used to illustrate features of more than one embodiment of the invention, and not all elements in the drawing may be necessary for a given embodiment.

[0012] Figure 1 This is a diagram illustrating an example operating room environment with a surgical robotic system according to various aspects of the subject matter; Figure 2 This is a schematic diagram illustrating an exemplary design of a robotic arm, tool drive, and cannula loaded with robotic surgical tools according to various aspects of the art of this subject. Figure 3A and Figure 3B This is a schematic diagram illustrating exemplary tool drive devices having and not having adjacent loaded tools according to various aspects of the subject matter; Figure 4A and Figure 4B This is an example of an end effector of a gripper according to various aspects of the subject matter, the end effector having a robot wrist, a pair of opposing jaws, and a pulley and cable system for connecting the robot wrist and the pair of jaws to an actuator of a tool drive. Figure 5A and Figure 5B This is a block diagram illustrating, according to various aspects of the subject matter, an exemplary control system for controlling the position and clamping force of an end effector of a robotic surgical tool; Figure 6 This is a flowchart of one embodiment of a method for homing a cable-driven instrument in a surgical robot system; and Figure 7 This is a block diagram of one implementation of a system for repositioning cable-driven robotic surgical instruments. Detailed Implementation

[0013] Returning the cable-driven robotic surgical instrument to its intended position for use in MIS. Returning involves placing the cable-driven robotic instrument in a known location such that the cable is taut and the distal end of the instrument is in its in-situ position. To handle undesirable cable elongation, the elongation is determined to establish an updated or calibrated actuator position to allow for return (i.e., placing the instrument in its in-situ position). Calibration positions the wrist as close as possible to its factory-set in-situ configuration.

[0014] Figures 1 to 5BAn example of a cable-driven robotic surgical instrument and a robotic surgical system for using the instrument is illustrated. This example is used for... Figure 6 and Figure 7 The repositioning method and system can be used. Other cable-driven surgical instruments and / or robotic surgical systems can also be used.

[0015] Generally, an end effector, including a robotic wrist and one or more jaws, can be connected to the actuator via a metal cable or wire. The wire can operate, for example, in pairs, where pulling one wire exerts a counterforce on the other wire in the pair; thus, the robotic wrist can act as an anti-robotic wrist. Jaws are used in this example, but other surgical robotic instruments for various applications can also be used. These surgical robotic instruments include grippers, forceps, scissors, needle actuators, retractors, forceps, and cauterization instruments.

[0016] Figure 1 This is a diagram illustrating an example operating room environment with a surgical robot system 100 according to various aspects of the subject matter technology. For example... Figure 1 As shown, the surgical robot system 100 has a surgeon's console 120, a control tower 130, and one or more surgical robotic arms 112 located at a surgical robot platform 110 (e.g., a table or bed, etc.), wherein surgical tools with end effectors are attached to the distal end of the robotic arm 112 for performing surgical procedures. The robotic arm 112 is shown as a tabletop mounted system, but in other configurations, the robotic arm may be mounted on a trolley, ceiling or sidewall, or other suitable supporting surface.

[0017] Generally, users (such as surgeons or other operators) can remotely manipulate the robotic arm 112 and / or surgical instruments (e.g., teleoperation) using a user console 120. The user console 120 may be located in the same operating room as the robotic system 100, such as... Figure 1 As shown. In other environments, the user console 120 may be located in an adjacent or nearby room, or remotely operated from a different building, city, or country. The user console 120 may include a seat 122, foot controls 124, one or more handheld user interface devices 126, and at least one user display 128 configured to display a view, for example, of a surgical site inside a patient's body. As illustrated in the exemplary user console 120, a surgeon located in the seat 122 and observing the user display 128 can manipulate the foot controls 124 and / or the handheld user interface device 126 to remotely control the robotic arm 112 and / or surgical instruments mounted to the distal end of the arm.

[0018] In some slightly different scenarios, the user can also operate the surgical robot system 100 in "on-bed" (OTB) mode, in which the user is positioned to the patient's side and simultaneously manipulates both robot-driven tools / end effectors attached to the patient (e.g., holding a handheld user interface device 126 with one hand) and manual laparoscopic tools. For example, the user's left hand can manipulate the handheld user interface device 126 to control the robotic surgical components, while the user's right hand can manipulate the manual laparoscopic tools. Thus, in these different scenarios, the user can perform both robot-assisted MIS and manual laparoscopic surgery on the patient.

[0019] During an exemplary procedure or surgical operation, the patient is aseptically prepared and covered for anesthesia. Initial approach to the surgical site can be manually performed using the robotic system 100 in a retracted or collapsed configuration to facilitate access. Once approach is complete, initial positioning and / or preparation of the robotic system can be performed. During the procedure, the surgeon in the user console 120 can use foot controls 124 and / or user interface devices 126 to manipulate various end effectors and / or imaging systems to perform surgical procedures. Manual assistance can also be provided at the operating table by a person in sterile gown, whose tasks include, but are not limited to, retracting tissue or performing manual repositioning or tool changes involving one or more robotic arms 112. Non-sterile personnel may also be present to assist the surgeon at the user console 120. When the procedure or surgery is completed, the robotic system 100 and / or the user console 120 may be configured or set to a state that facilitates one or more postoperative procedures, including but not limited to cleaning and / or sterilizing the robotic system 100, and / or medical record input or printout, whether electronic or paper, via the user console 120.

[0020] In some respects, communication between the robot platform 110 and the user console 120 can be achieved via a control tower 130, which can translate user commands from the user console 120 into robot control commands and send them to the robot platform 110. The control tower 130 can also send status and feedback from the robot platform 110 back to the user console 120. The connection between the robot platform 110, the user console 120, and the control tower 130 can be a wired and / or wireless connection, and can be proprietary and / or implemented using any of a variety of data communication protocols. Any wired connection can optionally be integrated into the floor and / or walls or ceiling of the operating room. The surgical robot system 100 can provide video output to one or more displays, including displays within the operating room and remote displays accessed via the Internet or other networks. Video output or feeds can also be encrypted to ensure privacy, and all or part of the video output can be stored on a server or electronic healthcare record system.

[0021] Figure 2 This is a schematic diagram illustrating an exemplary design of a robotic arm, tool actuator, and cannula loaded with robotic surgical tools, according to various aspects of the subject matter. Figure 2 As shown, the example surgical robot arm 112 may include multiple connectors (e.g., connector 204) and multiple joint modules (e.g., joint 202) for actuating the multiple connectors relative to each other. The connector modules may include various connector types, such as pitch connectors or roll connectors, which can substantially constrain the movement of adjacent connectors about certain axes relative to other axes. Figure 2 An exemplary design also illustrates a tool drive 210 attached to the distal end of a robotic arm 112. The tool drive 210 may include a cannula 214 coupled to its end for receiving and guiding surgical instruments 220 (e.g., endoscopes, suture devices, grippers, etc.). The surgical instrument (or “tool”) 220 includes an end effector 222 located at the distal end of the tool. Multiple articulated modules of the robotic arm 112 are actuable to position and orient the tool drive 210, which actuates the end effector 222 to perform robotic surgery.

[0022] Figure 3A and Figure 3B This is a schematic diagram illustrating exemplary tool drive devices, respectively having and not having adjacent loaded tools, according to various aspects of the subject matter. For example... Figure 3A and Figure 3BAs shown, in one variant, the tool drive 210 may include an elongated base (or “tower”) 310 having a longitudinal rail 312 and a tool holder 320 slidably engaged with the longitudinal rail 312. The tower 310 may be configured to be coupled to the distal end of a robot arm such that joint movements of the robot arm position and / or orient the tool drive 210 in place. Additionally, the tool holder 320 may be configured to receive a tool base 352 of a tool 220, which may also include a tool shaft 354 extending from the tool base 352 and through a sleeve 214, wherein an end effector 222 (not shown) is disposed at the distal end.

[0023] Additionally, the tool holder 320 can actuate a set of joints of the end effector by means of a cable system or line (the terms "cable" and "line" are used interchangeably) operated and controlled by an actuating drive (the terms "actuator," "motor," and "drive" are used interchangeably). The tool holder 320 can include different configurations with actuating drives. For example, a rotary shaft drive can include a motor with a hollow rotor and a planetary gear transmission at least partially disposed within the hollow rotor. Multiple rotary shaft drives can be arranged in any suitable manner. For example, the tool holder 320 can include six rotary drives 322A-322F arranged in two rows extending longitudinally along the base, slightly staggered to reduce the width of the holder and increase the compact nature of the tool drives. Figure 3B As clearly shown, rotary drive units 322A, 322B and 322C can typically be arranged in the first row, while rotary drive units 322D, 322E and 322F can typically be arranged in the second row, which is slightly longitudinally offset from the first row.

[0024] Figure 4A and Figure 4B This is an example of an end effector of an exemplary gripper 220 according to various aspects of the subject matter, the end effector having a robotic wrist, a pair of opposing jaws, and a pulley and cable system for coupling the robotic wrist and the pair of jaws to an actuator of a tool drive mechanism. It should be noted that although the following tool model and controller design are described with reference to an exemplary surgical robotic gripper, the proposed repositioning is applicable to any tool including an end effector coupled to a tool axis, wherein the cable is used to control the end effector. Similar tools include, but are not limited to, grippers, clamps, forceps, needle actuators, retractors, and cauterization instruments. Any number of wrist joints, such as… Figure 4A and Figure 4B The diagram shows one wrist joint, but zero, two, or more wrist joints can also be used. Any number of corresponding cables for controlling the end effector can be used, such as one, two, three, four, or more. Figure 4A and Figure 4BIn the example, four cables are used to control three degrees of freedom of the end effector.

[0025] like Figure 4A As shown, a pair of opposing jaws 401A and 401B are movably coupled to a first yoke 402 of the robot wrist via an extension shaft 412 along a first axis 410. The first yoke 402 is movably coupled to a second yoke 403 of the robot wrist via a second extension shaft 422 along a second axis 420. The pair of jaws 401A and 401B can each be coupled to or integrally formed with pulleys 415A and 415B via the extension shaft 412, such that both jaws can rotate about axis 410. Pulleys 425A, 425B, 425C, and 425D are coupled to the extension shaft 422 and rotate about axis 420. Pulleys 425A, 425B, 425C, and 425D are arranged as a first set of pulleys 425B and 425C on one side of the yoke 402 and a second set of pulleys 425A and 425D on the other side of the yoke 402. Pulleys 425A and 42C are outer pulleys, and pulleys 425B and 425D are inner pulleys. Similarly, the third set of pulleys 435A, 435B, 435C, and 435D are coupled to the third extension shaft 432 and rotate about the axis 430 which is parallel to the axis 420.

[0026] The gripper 220 can be actuated to move one or both of the jaws 401A and 401B about axis 410 in various ways. For example, jaws 401A and 401B can open and close relative to each other. Jaws 401A and 401B can also be actuated to rotate together as a pair to provide deflection motion of the gripper 220. Furthermore, the first yoke 402, pulleys 415A and 415B, and jaws 401A and 401B can rotate about axis 420 to provide pitch motion of the gripper 220. These movements of the jaws of the robot wrist and / or tool can be achieved by controlling four independent cables 405A-405D. Figure 4A As shown, cable 405A may begin (or terminate) on one side of pulley 415A and be routed along pulleys 425A and 435A, and cable 405B is configured to terminate on the other side of pulley 415A and be routed through pulleys 425B and 435B. Similarly, another pair of cables 405C and 405D may be coupled to jaw 401B. For example, cable 405C extends from one side of pulley 415B to pulleys 425C and 435C; and cable 405D is routed through pulleys 425D and 435D and terminates on the other side of pulley 415B. A third set of pulleys 435A, 435B, 435C, and 435D is arranged in such a way that cables 405A-405D remain attached to the second set of pulleys 425A-425D and slip or slide relative to pulleys 425A-425D.

[0027] Controlling the movement of the gripper 220 via four independent cables offers several advantages. One advantage is the reduction in the number of cables extending from the tool base 352 to the robot wrist compared to typical market designs using six cables (or three cable loops with six cable ends). Fewer cables reduce tool size and wrist assembly complexity, which can be advantageous for minimally invasive surgical procedures or non-surgical applications. Furthermore, instead of two or three cable loops, the arrangement of four independent cables not only allows for independent control of the tension on each cable without the need for pre-tensioning, but also enables variable compliance and increased sensitivity to external loads in the wrist joint. Additionally, the tension on each cable can be independently readjusted, which further enhances tool performance.

[0028] like Figure 4A and Figure 4B As shown, the gripper 220 can be actuated to move the jaws 401A and 401B in various ways, such as by imparting motion to one or more of the pulleys 415A, 415B, 425A, 425B, 425C, and 425D to thereby impart motion to the first yoke 402 and / or one or both of the jaws 401A and 401B for gripping (e.g., the jaws rotate independently about axis 410) (three degrees of freedom), deflection (e.g., the jaws rotate together about axis 410), and pitch (e.g., the jaws rotate about axis 420). The cables 405A-405D can be divided into two opposing pairs, such that when one cable in the opposing pair is actuated or tensioned while the other cable is released, the jaws will rotate in one direction. When only the other cable is tensioned, the jaws will rotate in the opposite direction.

[0029] For example, cables 405A and 405B are a first pair of countermeasures for moving jaws 401A, and cables 405C and 405D are a second pair of countermeasures for controlling jaws 401B. When cable 405A is tensioned (e.g., by rotating drive 322), a -322 fWhen cable 405B is released, jaws 401A close (moving toward the relative jaws 401B). Conversely, when cable 405B is tensioned and cable 405A is released, jaws 401A open (moving away from the relative jaws 401B). Similarly, when tensioned, cable 405C closes jaws 401B (moving toward the relative jaws 401A), and cable 405D opens jaws 401B (moving away from the relative jaws 401A), while another cable is released. As another example, the clamping force between jaws 401A and 401B can be achieved by continuing to tension cables 405A and 405C (while simultaneously releasing cables 405B and 405D) after the jaws have closed (contacted each other).

[0030] When two cables of one pair are simultaneously tensioned while two cables of another pair are released, pulley 415A or pulley 415B does not rotate. Instead, the first yoke 402, together with jaws 401A and 401B, is given pitch about axis 420 by pulleys 415A and 415B. For example, when a pair of cables 405A and 405B are simultaneously tensioned while a pair of cables 405C and 405D are released, the jaws (together with the yoke 402) pitch out of the paper plane. However, when two cables 405C and 405D are simultaneously tensioned and the pair 405A and 405B remain released, the jaws pitch in the paper plane.

[0031] Figure 4B This is a schematic diagram illustrating exemplary angular definitions for various movements of the gripper 220 according to various aspects of the subject matter. The angles are defined with reference to axes 410 and 420, and to axis 452 of the first yoke 402 and axis 453 of the second yoke 403. For example, as... Figure 4B As shown, the angle (θ1) between axes 452 and 453 can represent the rotation angle of the yoke 402 about axis 420, which can also be defined as the pitch angle (θ) of the gripper 220. 俯仰 (while) Figure 4A In this configuration, the axis 452 of the yoke 402 is superimposed on the axis 453 of the yoke 403 because the jaws remain in the reference position (i.e., without pitch motion). Furthermore, angles (θ2) and (θ3) can represent the angles between each of the jaws 401A and 401B and the axis 452 of the yoke 402 (as the origin), respectively. To distinguish the sides of the axis 452, angles (θ2) and (θ3) can take different signs. For example, as... Figure 4B As shown, angle (θ2) is negative and angle (θ3) is positive.

[0032] To perform control tasks, it is often beneficial to define a consistent coordinate system for the joint angles. For example, the jaw angle (θ) 钳口The angle between the two jaws 401A and 401B is the deflection angle (θ). 偏转 The angle between the axis 45° and the line bisecting the jaw angle is denoted by θ. Therefore: exist Figure 4B The conversion between the angle in the original text and the newly defined angle is as follows: In addition, the following naming conventions can be established for the geometry of the pulleys: a)r 11 It refers to the radius of the outer pulleys 425A and 425C on which cables 405A and 405C are located, respectively; b)r 12 It is the radius (r) of the inner pulleys 425B and 425D on which cables 405B and 405D are located respectively. 11 It can be equal to or not equal to r 12 ); c)r 21 It is the radius of the pulley 415A on the side where cable 405A is located (see the center of pulley 415A and shaft 412, as shown). Figure 4A (as shown) d)r 22 It is the radius of the pulley 415A on the side where cable 405B is located (see the center of pulley 415A and shaft 412, as shown). Figure 4A (as shown) e) r 31 It is the radius of the pulley 415B on the side where cable 405C is located; and f)r 32 It is the radius of the pulley 415B on the side where cable 405D is located.

[0033] Although the above example has a symmetrical design, r 31 =r 21 r 32 =r 22 and r 21= r 22 (like Figure 4A (as shown), but in some other designs, r can also be made 31 =r 21 =r 32 =r 22 And r 11 =r 12 Asymmetric design can be used.

[0034] The cable tension (ξ) [4×1] ) and joint torque (τ) [3×1] The relevant fundamental equation is expressed by the following formula: τ[ 3×1 ]= B [ 3×4 ]·ξ [4×1] (3) The matrix (B) has the following form: Furthermore, (ξ1, ξ2, ξ3, ξ4) correspond to the cable tensions on cables 405A, 405B, 405C, and 405D, respectively.

[0035] ξ [4×1] =[ξ1ξ2ξ3ξ4] T (5) In equation (1), (τ) [3×1] A vector is a virtual joint torque applied by the cable, which enables the joint to overcome friction and resist external forces. Vector ( τ[3×1] It has three components: τ [3×1] =[τ1τ2τ3] T (6) Where (τ1) is the pitch joint torque, and (τ2) and (τ3) are the joint torques of jaw 401A and jaw 401B, respectively.

[0036] The kinematic relationship between the ideal cable displacement (assuming the cable is inelastic) and the jaw angle is as follows: q [4×1] [ q 1 q 2 q 3 q 4] T =B T ·θ [3×1] (7) Where (q) [4×1] ) is a four-element vector containing the ideal displacement of cables 405A-405D, and (θ) [3×1] )yes Figure 4B The vector of angles illustrated in: θ [3×1] =[θ1θ2θ3] T (8) In reality, cables are elastic, and the actual cable displacement and the ideal cable displacement are related as follows: ξ [4×1] k e ( x [4×1] −B T ·θ [3×1](9) Where k e It is the elastic constant of the cable, expressed in N / m (assuming all cables are similar).

[0037] The angular position and clamping force of the distal end effector of a robotic surgical instrument are controlled. The end effector may include a robotic wrist and a pair of opposing components (e.g., jaws or claws), each movable between an open and closed position, actuated by two opposing wires. A total of four wires may be driven independently by actuators or motors, as illustrated in Figures 3 and 4. The control system may include a feedback loop involving position and / or velocity feedback from the actuators and force feedback measured on the four wires to achieve the desired position and clamping force. In some implementations, the actuator controller may operate in a position plus feedforward current mode. For example, the position controller may drive the distal end effector to a desired angular position in space based on position feedback, while the clamping force controller provides additional feedforward current based on the clamping force measured by force sensors on the four wires to achieve the desired clamping force between the opposing components or jaws 401A-B.

[0038] Figure 5A This is a block diagram illustrating an advanced control system for controlling surgical tools. The control system includes input 560, controller 562, device 564, output 568, and sensors and estimators 566 on the feedback path between output 568 and controller 562. Device 564 may include tool actuators and end effectors (e.g., Figure 5B The actuator unit 510 and the cable and wrist linkage 512 are included. The controller 562 may include one or more processors configured by software instructions stored in memory to calculate the movement of the device 564 in response to input 560, which may indicate the desired movement of the end effector of the surgical tool. Thus, commands generated by the controller 562 can drive the tool actuator to facilitate the desired movement of the end effector. Outputs 568 (such as position, velocity, cable tension, and / or clamping force of the end effector) may be directly measured or estimated by sensors and estimators 566 and fed back to the controller 562 for closed-loop control.

[0039] Figure 5BThis is a block diagram illustrating an exemplary control system 500 for controlling the position and gripping force of an end effector of a robotic surgical tool. The robot control system 500 includes an input processing unit 502, an actuator command generator 504, a position controller 506, a gripping force controller 508, a device including one or more actuator units 510 and / or cables and wrist links 512, a relaxation controller 514, a position estimator 522, and a gripping force estimator 524. It should be noted that additional, different, or fewer components may be used compared to those shown in the figure. Modifications to the arrangement and type of components are also possible.

[0040] The input processing unit 502 and the actuator command generator 504 receive the desired angular position of the end effector and convert the desired angular position into a corresponding actuator position command (via inverse kinematics algorithm) and / or clamping force command, which is output to the position controller 506 and / or the clamping force controller 508. For example, the input desired angular position may include the pitch angle (θ). 俯仰 ), deflection angle (θ) 偏转 ) and jaw angle (θ) 钳口 When the angle is not less than a threshold, the desired jaw angle input can be considered a position control command. This threshold corresponds to the angle at which both jaws just simultaneously contact the object between them. When there is no object to grip, the threshold is zero degrees when the jaws begin to touch each other. For any desired jaw angle less than the threshold, the input can be converted into a desired clamping force command and forwarded to a clamping force controller 508, which, in addition to the position command, can generate a current command to achieve the desired clamping force. For further control and operation, see U.S. Patent No. 10,166,082.

[0041] Figure 6 One embodiment of a method for homing a cable-driven instrument 220 of a surgical robotic system is shown. Homaging configures the surgical instrument in a predetermined posture, allowing the operator to provide relative changes during surgery. Engaged motors move to a calibrated position to place the instrument in its in-situ configuration. To handle cable elongation that could cause a deviation from the calibrated motor position, tension is applied to the cable at one or more known positions to determine any offset or adjustment to the motor position.

[0042] This method is by Figure 1 , Figure 2 or Figure 3A and Figure 3B Performed by a surgical robotic system or another surgical robotic system. In one embodiment, Figure 7 The surgical robotic system performs this method. Figure 4A and Figure 4B The method is performed using surgical instruments or another instrument.Figure 4A and Figure 4B In the example, four cables control three degrees of freedom for a cable-driven instrument. Other numbers of cables with the same or fewer degrees of freedom as the instrument can be used. A programming processor (also referred to herein as processing logic) of the control unit or other controller executes this method when the surgical tool 220 is connected to the tool driver 210. Once the identity of the surgical tool 220 is determined, the processor performs homing. Memory may store instructions for programming the processor to perform homing.

[0043] The actions may be performed in the order shown or a different order. For example, actions 610 and 620 may be performed simultaneously. As another example, actions 610-630 may be repeated during surgery or for different surgical procedures. Additional, different, or fewer actions may be provided. For example, action 600 may not be provided if engagement has previously occurred or been fixed. As another example, action 610 may not be provided if instrument 220 is positioned in a known location other than its original location, so action 620 would apply tension at the other known location. Action 640 may also not be provided. In other examples, actions may be provided for positioning the robotic arm 112 for teleoperation, connecting instrument 220 to actuator 210, and / or for surgical use of the engaged and repositioned instrument 220.

[0044] The process begins once the tool actuator 210 is connected to the tool instrument 220. A processor (e.g., a controller or control unit) detects engagement between two or more rotary drive pads or disks 322 and corresponding rotary tool pads. The drive disk 322 engages with the tool disk using a releasable engagement (e.g., spring-loaded, physical barrier, or friction fit). The process can begin upon or after the detection of connection and a subsequent initialization event (e.g., user-indicated readiness).

[0045] In action 600, the cable-driven instrument 220 engages with the tool actuator 210 of the surgical robotic arm 112. While the tool actuator 210 may be connected to the instrument 220, the tool disk may not engage with the drive disk 322. The processor controls the engagement. The motor (e.g., actuator) of the tool actuator 210 rotates. The rotation of the motor is performed under position control, but other control modes may be used. The drive disk 322 comes into frictional contact with the tool disk. The rotation has sufficient force to overcome static friction, so that the drive disk 322 rotates relative to the tool disk, which is linked to the surgical instrument (e.g., surgical instrument 220). The rotation should ultimately result in the engagement of physical engagement mechanisms on the tool (e.g., protrusions and recesses, shaped extensions and slots, protrusions and stops, and / or snap-fit ​​retainers and extensions) with the drive disk. This engagement correlates the position of the motor with the position of the surgical instrument 220.

[0046] Based on one or more monitored motor operating parameters (e.g., current), processing logic detects when the drive disk mechanically engages with the tool disk. In one embodiment, detection is performed when at least one of the monitored motor operating parameters meets a corresponding condition or threshold, or in response to such a condition. The monitored motor operating parameters may correspond to those controlled by the processing logic to cause motor movement (e.g., torque, speed). The processing logic repeatedly checks to see if the engagement condition has been met, for example, whether the monitored motor operating parameter has reached a threshold. If so, it is marked as a mechanical engagement event, indicating that the drive disk has mechanically engaged with the corresponding tool disk.

[0047] In action 610, the processor positions the cable-driven instrument 220 in its home position. Positioning may be inaccurate or incomplete due to any elongation of the cables 405A-D. After engagement, the motor of the tool driver 210 is positioned in a calibrated position for the home configuration of the cable-driven instrument 220. In position mode control, the motor is moved to adjust the cable so that the instrument 220 is in the calibrated posture. The motor is positioned using an absolute position sensor (e.g., an encoder), and the cable is adjusted to move the cable-driven instrument 220 to the calibrated posture. For example, Figure 4A This indicates the in-situ position or orientation of the surgical instrument 220. Assuming no cable elongation, the motor rotates to provide the original orientation.

[0048] In one embodiment, the calibration position of the motor is established from factory calibration. In the factory, when the tool is manufactured, the distal end of the instrument is positioned and held in place, and all four cables are tensioned to a set tension value (see below for some options for tension control), at which point the actuator's position relative to an absolute reference point is stored in the device. All tool drive motors are commanded (e.g., in position mode) to position themselves in their factory positions, which are stored in instrument 220. In other embodiments, the calibration position is based on a previously updated or set position from previous executions of actions 610-630.

[0049] In an alternative embodiment, the processor controls a motor to position the cable-driven instrument 220 in a hard-restrained position. For example, the cable-driven instrument 220 is positioned to apply equal pressure against a cannula on both jaws, with the surgical instrument 220 placed within the cannula for surgical use. The hard-restrained position is the in-situ position.

[0050] In action 620, the processor controls the motor to apply tension to cables 405A-D of the cable-driven device 220. The motor removes any slack in the cables when the device 220 is in its in-situ configuration. The application of tension removes slack, including any elasticity, in the transmission mechanism (e.g., the cable) from the motor to the end effector when in the in-situ position. The processor ensures that cables 405A-D are taut, thus establishing a kinematic connection between the actuator and the wrist (also referred to as the distal end of the device).

[0051] Equal tension is applied to the different cables to keep the device 220 in its home position. Any type of control can be used. For example, force or torque control modes can be used to apply a threshold tension to each cable. In one approach, the motor operates in force mode, and an external impedance loop is used to control the position. The motor is placed in force mode with an external impedance loop. Force controllers on four cables 405A-D are used to establish small, similar cable tension values ​​(approximately 5N to 20N). Position control via the external impedance loop ensures the wrist position is maintained in the factory home position (assuming the factory position is zero orientation). The motor can be commanded in the actuator space or indirectly via the joint space.

[0052] In another approach, the motor operates in position mode, with force controlled via admittance control. Position control mode is used to apply tension while maintaining posture. Each individual actuator is placed in position mode, and the cable force associated with each motor is adjusted via changes in actuator position (admittance control method).

[0053] In another approach, a threshold tension is applied to all cables, causing the cable-driven device 220 to remain in place using zero space. Zero-space control can be used when a larger number of cables and motors (e.g., four) control a smaller number of degrees of freedom (e.g., three). The actuator is placed in a position mode. The actuator is driven in the zero space of the wrist until a desired minimum tension (e.g., equal to the factory tension) is achieved in the cables. Additional cables relative to the degrees of freedom are used to operate the motors to apply tension without altering the orientation of the device 220.

[0054] Other methods may be used. Any method can be used to apply a threshold tension to either the cable or the drive mechanism from the motor to the end actuator. In the presence of slack, the position of the motor for a given cable may change when tension is applied. This change begins in situ and occurs due to the amount of elongation.

[0055] In action 630, the processor determines any elongation of cables 405A-D based on the forces on cables 405A-D and / or the position of the actuator of the device 220 driven by the operating cables. For example, these forces establish a threshold tension on cables 405A-D. The position of the actuator when at this threshold tension is sensed, such as using an absolute position sensor (e.g., an encoder). These positions are updated or new positions relative to the in-situ configuration, assuming the device 220 is in its original posture. The difference from the previous position is the elongation. The updated position is the position relative to the in-situ configuration and represents the determined elongation.

[0056] Actions 632 and 634 represent another implementation. This implementation provides greater accuracy by not assuming that the instrument 220 is in its original position using the motor before applying tension. Additional, different, or fewer actions can be provided to determine the elongation and / or update the calibration.

[0057] In action 632, the cable-driven device 220 joints move to one or more predetermined positions. The device 220 moves to one or more configurations having known references (such as hard constraints). The joint movement begins from an initial posture or position. Alternatively, the initial posture or position is used as one of the predetermined positions.

[0058] An example predetermined position is the jaw closure position, such as... Figure 4A As shown. The posture can be associated with a given amount of force on the jaws abutting each other, such as a non-zero clamping force when the jaws press against each other. Any level of force can be used, such as 3N to 20N. Another example predetermined position is the jaw-cannula collision position. For example, without changing the angle of the wrist or joint, the jaws move equally to an open position to collide with the housing or outer shell (e.g., the cannula into which the surgical instrument 220 has been inserted for surgical procedures).

[0059] In action 634, the position of the actuator and the force applied at each predetermined position are used to update the motor position. The amount of cable elongation can be determined, such as the length or change in length from the motor position when the device 220 is in a predetermined position. The difference between the expected position and the actual position of the motor indicates the amount of elongation.

[0060] For repositioning, the elongation is used to determine a new, calibrated, or updated motor position. The elongation is used to update the motor's calibration position. The motor's position after tension is applied to the cable is used to update the motor's calibration position. The calibration or home position of the motor used to set the instrument 220 in place is updated based on the motor's position when the cable-driven instrument 220 is in one or more predetermined positions (such as the jaw closed position and / or the jaw impact position with the cannula).

[0061] Determination and updating are performed for each of the motor and the corresponding cables 405A-D. The elongation of different cables 405A-D can be based on measurements taken at different predetermined locations. Alternatively, multiple elongation measurements are performed on a single cable 405, and the results are averaged.

[0062] In one implementation, in action 632, the joint moves to two known configurations to determine the unknown cable elongation. The first configuration is with the jaws in a fully closed position. The jaws are commanded to close until a identifiable change in cable force (or current spike) is detected. While ensuring jaw contact is important, a more robust approach is to use jaw contact with a non-zero clamping force. The second configuration can be achieved via joint movement until both jaws collide with the cannula (or another rigid obstacle). The collision occurs in either the pitch or yaw direction, but not simultaneously in both. Collision detection is performed from spikes in cable force or motor current. In each of these two known configurations, cable tension and actuator position are recorded for updating. The difference in actuator position indicates the elongation, which can be added to the actuator position used for homing.

[0063] In a technique to improve the accuracy of updates and corresponding repositioning, the elongation of cable 405A-D is determined using the motor position, force measurements at a predetermined position, and cable elasticity information. Figure 4A and Figure 4B An example surgical instrument 220 with four cables 405A-D controls the wrist, and a motor (e.g., a DC motor, such as a brushless DC motor) actuates and pulls the cables 405A-D. When pulled, the four cables 405A-D perform the following basic actions relative to the two jaws: cable 405A closes jaw A (401A), cable 405B opens jaw A (401A), cable 405C closes jaw B (401B), and cable 405D opens jaw B (401B).

[0064] The fundamental equations relating the three joint angles ( ) to the four ideal cable movements ( q) are as follows: (10) Where matrix B has the following form , and (11) q is the ideal movement of cable 405A-D, where cable 405A-D is rigid. The expanded form of equation (10) provides the movement of each cable 405A-D (cables 1-4) as follows: The processor determines the change in length of cable 405A-D of the cable-driven device 220 based on the force on cables 405A-D when they are in the jaw-closed position with a predetermined non-zero clamping force. The elongation is determined for updating based on the relationship given by Hooke's Law. Cables 405A-D are elastic, and the cable force and elongation obey Hooke's Law, which states for each cable 405A-D (cables 1-4) as follows: Where k is the cable elasticity and x is the actuator displacement. The elasticity k of cables 405A-D is the same or equal, but different values ​​of k can be used for different cables 405A-D with different elasticities. If cables 405A-D are not assumed to be elastic, the above equations are replaced by nonlinear equations related to cable elongation and force.

[0065] The undesired (and unknown) permanent cable elongation on the four cables 405A-D (cable numbers 1-4) is Δ1 to Δ4. To perform homing, in action 600, the instrument 220 is loaded or connected to the tool driver 210, and the motor engages with the instrument 220. In action 610, the actuator is then driven to its factory or previously established home position. In action 620, the instrument 220 is positioned in the predetermined position with the jaws closed. To ensure contact between the jaws 401A-B, minimum tension and force control are used. A small clamping force (e.g., 3 N) is applied by tensioning the cables 405A-D. In this case, four cable forces ξ1 to ξ4 are established in the cables. Using equation (13), the forces of the four cables 405A-D are: in to It refers to the movement of the actuator relative to its original position in the factory, and to Caused by unintended wrist movements (and unknown). If the wrist remains stationary in the pitch and yaw directions during jaw closure (i.e., the wrist remains in place). to The result will be zero, and Δ1 to Δ4 can be obtained directly from equation (14). However, this may not be the case.

[0066] When the motion is not zero, some assumptions can be used to solve for the changes in length Δ1 to Δ4. For example, in the jaw-closed position of jaw contact, the angle of one jaw 401A is equal to the angle of the other jaw 401B. In this case: As another example, the movement of one jaw 401A has the same magnitude and opposite direction as the movement of the other jaw 401B. According to equation (14), this relationship provides: This can then be used in equation (14) to obtain: Eliminate from these equations and ,get: Based on the assumption that the changes in length of cables 405A and 405C used to close jaws 401A-B are equal, and the changes in length of cables 405B and 405D used to open jaws 401A-B are equal, the sum from Equation 18 can be divided by 2. The division provides the resulting changes in length. A similar method can be used to determine the same elongation by using another predetermined location (such as the point where the jaws collide with the cannula).

[0067] Taking into account the elongation of cables 405A-D of the cable-driven device 220, the processor uses the elongation to change the motor's calibration position. For each cable 405A-D and its corresponding motor, the corresponding elongation is added to the motor's previous calibration position. In position mode, the actuator is commanded to return to the factory or previous position plus the elongation value to obtain the updated calibration or home position of the motor.

[0068] In action 640, the surgical robot system operates a cable-driven instrument 220 during surgery. For example, movement of the user interface device 126 and / or foot pedal 124 is translated into joint commands, such as using inverse kinematics. Actuators move and are controlled in a manner that takes into account elongation. Using the updated calibrated or in-situ position of the motors, joint commands to move the motors cause the instrument 220 to operate in the desired manner. The cable-driven instrument 220 moves during surgery based on the updated calibrated position of the engaged motors. From or relative to the in-situ position, the angle of the joints of the cable-driven instrument 220 is changed. Alternatively or additionally, the jaws open or close. The amount of movement or opening and closing is partially controlled by the difference from the updated position.

[0069] Figure 7 This is a block diagram illustrating a surgical robotic system according to one implementation. The system may be, for example... Figures 1 to 3B The system uses surgical tools 700, such as... Figure 4A and Figure 4B As disclosed herein. Surgical robotic systems are used for repositioning, taking into account cable elongation and / or transmission deformation, such as for implementing... Figure 6 The method.

[0070] When engaged, the surgical tool 700 is connected to the actuator 730 (e.g., a motor) via a cable 710. Sensors 720, such as force sensors (e.g., force measurement sensors) and / or position sensors (e.g., encoders for absolute position), are used to control and / or determine the amount of elongation. A processor 740, using instructions in a non-transitory computer-readable storage medium 750, controls the operation of the actuator 730 using information from the sensors 720.

[0071] Surgical tool 700 is a gripper with two jaws, but may be another type of surgical instrument. Surgical tool 700 is connected by multiple cables 710 to a corresponding number of actuators 730, such as four cables connected to four engaged actuators 730. The cables 710 allow actuation of the actuators 730 to move surgical tool 700, such as opening and closing the jaws and / or rotating in a pitching and / or deflecting manner. In one embodiment, actuation causes surgical tool 700 to move with fewer degrees of freedom than the cables 710 present. For example, the surgical tool includes jaws with a wrist, thus having three degrees of freedom controlled by the four cables 710 and corresponding actuators 730.

[0072] Sensor 720 is configured to sense force and / or position. For example, sensor 720 is a force sensor, such as a strain gauge, on the shaft of cable 710 or actuator 730. Alternatively, force is sensed by current drawn by actuator 730. The force applied by actuator 730 to cable 710 and / or tool 700 is sensed. As another example, sensor 720 is a position sensor, such as an absolute position encoder, on actuator 730.

[0073] Processor 740 is a general-purpose processor, application-specific integrated circuit, field-programmable gate array, digital signal processor, controller, digital circuit, analog circuit, combination thereof, and / or other processor now known or later developed for robot control. Processor 740 is configured by software, hardware, and / or firmware to return actuator 730 and surgical tool 700 to their positions.

[0074] Processor 740 is configured to engage surgical tool 700 with actuator 730, controlling actuator 730 to configure surgical tool 700 in an in-situ configuration upon engagement (e.g., controlling actuator 730 to move to an in-situ position), and then apply pressure along cable 710. For example, processor 740 controls actuator 730 to apply pressure to cable 710 without movement of the surgical end effector. Pressure is sensed by sensor 720, causing a set or threshold amount of pressure to be applied to all cables 710. In one embodiment, processor 740 controls actuator 730 to apply pressure using operation in the null space provided by the difference between the number of cables and the fewer degrees of freedom. Actuator 730 can be controlled to move tool 700 to one or more predetermined positions, such as positions associated with hard constraints that can be detected independently of the position of actuator 730.

[0075] Processor 740 is configured to use pressure to determine the in-situ position of actuator 730 for the in-situ position of surgical tool 700. The in-situ position of actuator 730 may change over time as cable 710 elongates due to use, cleaning, and / or time. Processor 740 is configured to determine the in-situ position of actuator 730 by manipulating actuator 730 to position the surgical tool in one or more known configurations. The change in length of cable 710 can be determined based on the position of actuator 730, where tool 700 is in a known configuration (e.g., jaw closed or jaws at a cannula). The change in length is used to determine and set the in-situ position. For example, for each actuator 730, the difference between the current position and a past position of tool 700 at the same hard limit position indicates the amount of elongation. Taking into account the change in length of cable 710, this elongation, added to the in-situ position of actuator 730, yields an updated or corrected in-situ position.

[0076] The processor 740 can be configured to operate the tool 700 during surgical procedures. Using homing, the position of the tool 700 can be precisely controlled, such as relative to its home position. Accurate control can be provided throughout the tool 700's lifespan by updating the homing. During the patient's surgical procedure, the tool 700 is used in part based on the calibrated home position of the actuator 730.

[0077] Other exemplary embodiments include the following. Exemplary embodiments for one type of claim (e.g., system, method, computer program, or computer-readable storage medium) may be provided for other types (e.g., system as a method). Exemplary embodiments for one set (e.g., exemplary embodiments 1 to 9) may be used in other sets.

[0078] Exemplary Embodiment 1. A method for homing a cable-driven instrument of a surgical robot system, the method comprising: engaging the cable-driven instrument with a tool actuator of a surgical robot arm; after engagement, positioning a motor of the tool actuator to a first calibration position of an in-situ configuration of the cable-driven instrument; applying tension to a cable of the cable-driven instrument via the motor, the tension removing any slack in the cable of the cable-driven instrument in the in-situ configuration; updating the first calibration position of the motor based on the position of the motor after the tension is applied to the cable; and controlling the cable-driven instrument during surgery based on the updated first calibration position.

[0079] Example 2. The method according to Example 1, the method further comprising: moving the cable-driven device from the in-situ configuration joint to one or more predetermined positions; wherein the update includes updating based on the position of the motor when the cable-driven device is in the one or more predetermined positions.

[0080] Example 3. The method according to Example 2, wherein joint movement to the one or more predetermined positions includes joint movement to a jaw closed position and a jaw-collision position, and wherein updating includes updating based on the position of the motor when the cable-driven instrument is in the jaw closed position and the jaw-collision position.

[0081] Exemplary Embodiment 4. The method according to any one of Exemplary Embodiments 2 to 3, wherein joint movement to the one or more predetermined positions includes joint movement to a jaw closed position with a predetermined non-zero clamping force, and wherein updating includes determining the change in the length of the cable of the cable-driven device based on the force on the cable when the jaws are in the jaw closed position with the predetermined non-zero clamping force.

[0082] Example 5. The method according to example 4, wherein the update includes updating based on the relationship given by Hooke's Law.

[0083] Example 6. The method according to any one of Example 4 to 5, wherein the update includes updating based on the fact that the angle of the first jaw in the jaw closed position is equal to the angle of the second jaw and based on the fact that the movement of the first jaw and the movement of the second jaw have equal magnitudes and opposite directions.

[0084] Example 7. The method according to any one of example 4 to 6, wherein the update includes updating based on the assumption that the changes in the length of the cable used to close the first jaw and the second jaw are equal and that the changes in the length of the cable used to open the first jaw and the second jaw are equal.

[0085] Example 8. The method according to any one of example 1 to 7, wherein the update includes changing the first calibration position to take into account the cable elongation of the cable-driven instrument.

[0086] Exemplary Embodiment 9. The method according to any one of Exemplary Embodiments 1 to 8, wherein positioning includes positioning the motor using position mode control based on an absolute position sensor, wherein the first calibration position is derived from factory calibration.

[0087] Exemplary Embodiment 10. The method according to any one of Exemplary Embodiments 1 to 9, wherein the application includes applying the force when the motor is in force mode and the position is controlled by an external impedance loop, or applying the force when the motor is in position mode and the force is controlled by admittance control.

[0088] Exemplary Embodiment 11. The method according to any one of Exemplary Embodiments 1 to 10, wherein four cables control three degrees of freedom of the cable-driven device, and wherein applying includes applying threshold tension by driving the motor in zero space.

[0089] Exemplary Embodiment 12. The method according to any one of Exemplary Embodiments 1 to 11, wherein applying includes applying a threshold tension to all said cables such that the cable-driven device remains in the in-situ configuration.

[0090] Example 13. The method according to any one of Example 1 to 12, wherein the control comprises: (1) changing the angle of the joint of the cable-driven instrument, and / or (2) opening or closing the jaws of the cable-driven instrument, wherein the amount of (1) changing or (2) opening or closing is controlled by the difference from the updated first calibration position.

[0091] Exemplary Embodiment 14. A surgical robotic system for repositioning, the surgical robotic system comprising: a surgical tool connected by a first number of cables to a corresponding number of actuators, the surgical tool being connected such that actuation of the actuators causes the surgical tool to move with a fewer number of degrees of freedom than the first number; a first sensor configured to sense a force applied by the actuators; and a processor configured to control the actuators to apply pressure to the cables when the surgical actuators are not moving, the pressure being sensed by the first sensor, and the processor being configured to use the pressure to determine the in-situ position of the actuators relative to the in-situ position of the surgical tool.

[0092] Exemplary Embodiment 15. A surgical robot system according to Exemplary Embodiment 14, wherein the surgical tool includes jaws having wrists, and in the case that the first number is four, the surgical tool has three degrees of freedom, and wherein the processor is configured to control the actuator to apply pressure operating in the zero space provided by the difference between the first number and the fewer number.

[0093] Exemplary Embodiment 16. A surgical robot system according to any one of Exemplary Embodiments 14 to 15, wherein the processor is configured to engage the surgical tool with the actuator, control the actuator to configure the surgical tool in an in-situ configuration once engaged, and then apply the pressure.

[0094] Exemplary Embodiment 17. A surgical robot system according to any one of Exemplary Embodiments 14 to 16, wherein the processor is configured to determine the in-situ position of the actuator by operating the actuator to position the surgical tool in one or more known configurations.

[0095] Exemplary Embodiment 18. The surgical robot system according to Exemplary Embodiment 17, wherein the processor is configured to determine the in-situ position based on changes in the length of the cable.

[0096] Exemplary Embodiment 19. A method for homing a cable-driven instrument of a surgical robot system, the method comprising: positioning the cable-driven instrument in an in-situ position; applying tension to a cable of the cable-driven instrument while in the in-situ position; determining an elongation of the cable based on forces on the cable and a position of an actuator that operates the cable-driven instrument in two or more configurations having a known reference; and, during surgical procedures, operating the cable-driven instrument under the control of the actuator, taking into account the elongation.

[0097] Example 20. The method according to example 19, wherein determining the elongation includes determining it based on the difference between the position of the actuator and a predetermined position and the force.

[0098] The foregoing description of exemplary embodiments of the present invention, including those described below in the summary, is not intended to be exhaustive or to limit the invention to the specific forms disclosed. While specific embodiments and examples of the invention have been described herein for illustrative purposes, various modifications are possible within the scope of the invention, as will be recognized by those skilled in the art. For example, although Figure 4A and Figure 4B A surgical tool 220 with a specific cable-driven transmission mechanism is depicted, but the above-described repositioning process is also applicable to other types of surgical tools with different transmission mechanisms (not necessarily cable-driven). These modifications can be made to the invention based on the detailed description above. The terminology used in the following claims should not be construed as limiting the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is fully defined by the following claims, which will be interpreted according to the claims.

Claims

1. A method for homing a cable-driven instrument of a surgical robot system, the method comprising: Engage the cable-driven instrument with the tool actuator of the surgical robot arm; After the engagement, the motor of the tool driver is positioned at a first calibration position in the in-situ configuration of the cable-driven instrument. Tension is applied to the cable of the cable-driven device by the motor, thereby removing any slack in the cable of the cable-driven device in the in-situ configuration. The first calibration position of the motor is updated based on the position of the motor after the tension is applied to the cable; as well as The cable-driven instrument is controlled during surgical procedures based on an updated first calibration position.

2. The method according to claim 1, further comprising: The cable-driven device is moved from the in-situ configuration joint to one or more predetermined positions. The updates include updates based on the position of the motor when the cable-driven device is in one or more predetermined positions.

3. The method of claim 2, wherein joint movement to the one or more predetermined positions includes joint movement to a jaw closed position and a jaw-to-cannula collision position, and wherein updating includes updating based on the position of the motor when the cable-driven instrument is in the jaw closed position and the jaw-to-cannula collision position.

4. The method of claim 2, wherein joint movement to the one or more predetermined positions comprises joint movement to a jaw closed position with a predetermined non-zero clamping force, and wherein updating comprises determining a change in the length of the cable of the cable-driven device based on the force on the cable when the jaws are in the jaw closed position with the predetermined non-zero clamping force.

5. The method of claim 4, wherein the update comprises updating based on the relationship given by Hooke's Law.

6. The method of claim 4, wherein the update comprises updating based on the angle of the first jaw being equal to the angle of the second jaw in the jaw closed position and based on the movement of the first jaw having equal magnitude and opposite direction to the movement of the second jaw.

7. The method of claim 4, wherein the update comprises updating based on the assumption that the changes in the length of the cable used to close the first jaw and the second jaw are equal and that the changes in the length of the cable used to open the first jaw and the second jaw are equal.

8. The method of claim 1, wherein the update includes changing the first calibration position to take into account the cable elongation of the cable-driven instrument.

9. The method of claim 1, wherein positioning includes using position mode control based on an absolute position sensor to position the motor, wherein the first calibration position is derived from factory calibration.

10. The method of claim 1, wherein the application includes applying the force when the motor is in force mode and the position is controlled by an external impedance loop, or applying the force when the motor is in position mode and the force is controlled by admittance control.

11. The method of claim 1, wherein four cables control three degrees of freedom of the cable-driven device, and wherein applying includes applying threshold tension by driving the motor in zero space.

12. The method of claim 1, wherein applying includes applying a threshold tension to all of the cables such that the cable-driven device remains in the in-situ configuration.

13. The method of claim 1, wherein the control comprises: (1) Change the angle of the joint of the cable-driven device, and / or (2) open or close the jaws of the cable-driven device, wherein the amount of (1) change or (2) opening or closing is controlled by the difference from the updated first calibration position.

14. A surgical robotic system for repositioning, the surgical robotic system comprising: A surgical tool, wherein the surgical tool is connected by a first number of cables to a corresponding number of actuators, the surgical tool being connected such that actuation of the actuators causes the surgical tool to move with a fewer number of degrees of freedom than the first number; A first sensor, configured to sense the force applied by the actuator; and A processor configured to control the actuator to apply pressure to the cable when the surgical actuator is not moved, the pressure being sensed by the first sensor, and the processor configured to use the pressure to determine the in-situ position of the actuator relative to the in-situ position of the surgical tool.

15. The surgical robot system of claim 14, wherein the surgical tool includes jaws having a wrist, having three degrees of freedom when the first number is four, and wherein the processor is configured to control the actuator to apply the pressure in a zero space provided by the difference between the first number and the fewer number.

16. The surgical robot system of claim 14, wherein the processor is configured to engage the surgical tool with the actuator, control the actuator to configure the surgical tool in an in-situ configuration upon engagement, and then apply the pressure.

17. The surgical robot system of claim 14, wherein the processor is configured to determine the in-situ position of the actuator by operating the actuator to position the surgical tool in one or more known configurations.

18. The surgical robot system of claim 17, wherein the processor is configured to determine the in-situ position based on changes in the length of the cable.

19. A method for homing a cable-driven instrument of a surgical robot system, the method comprising: Position the cable-driven device in its original position; Tension is applied to the cable when the cable-driven device is in the home position; The elongation of the cable is determined based on the force on the cable and the actuator operating the cable-driven device in two or more configurations with known references. as well as In surgical procedures, the cable-driven instrument is operated under the control of the actuator, taking into account the elongation.

20. The method of claim 19, wherein determining the elongation includes determining it based on the difference between the position of the actuator and a predetermined position and the force.

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