Systems and methods for variable speed surgical instruments

Abstract

The present application relates to systems and methods for variable speed surgical instruments, and discloses a system and method for variable speed control of a surgical instrument in a computer-assisted medical device, the surgical instrument comprising an end effector located at a distal end of the instrument, an actuator, and a drive mechanism for coupling a force or torque from the actuator to the end effector. To perform an operation with the instrument, the computer-assisted medical device sets a speed set point of the actuator to an initial speed, monitors the force or torque applied by the actuator, reduces the speed set point when the applied force or torque is above a first threshold, increases the speed set point when the applied force or torque is below a second threshold, reduces the speed set point to zero when the applied force or torque is above a maximum threshold, and drives the actuator based on the speed set point. The first threshold and the second threshold are below the maximum threshold.

Description

[0001] This application is a divisional application of Chinese patent application 201780005448.4, entitled “System and method for variable speed surgical instruments”, filed on January 27, 2017.

[0002] Related Applications

[0003] The present disclosure claims priority to U.S. Provisional Patent Application No. 62 / 288,784, filed on January 29, 2016, entitled “System and Method for Variable Velocity Surgical Instrument,” and U.S. Provisional Patent Application No. 62 / 408,283, filed on October 14, 2016, entitled “I-Beam Stapler Controls Supplement,” both of which are incorporated herein by reference in their entirety. Technical Field

[0004] The present disclosure relates generally to the operation of devices having articulated arms and end effectors, and more particularly to the operation of minimally invasive surgical instruments having variable speed control. Background Art

[0005] More and more equipment is being replaced by autonomous and semi-autonomous electronic devices. This is especially true in today's hospitals, where a large number of autonomous and semi-autonomous electronic devices are found in operating rooms, interventional rooms, intensive care units, emergency rooms, and the like. For example, traditional manual surgical instruments are being replaced by computer-assisted medical devices.

[0006] Minimally invasive surgical techniques using computer-assisted medical devices generally attempt to perform surgery and / or other routines while minimizing damage to healthy tissue. Some minimally invasive routines can be performed remotely using computer-assisted medical devices and surgical instruments. With many computer-assisted medical devices, surgeons and / or other medical personnel can generally use one or more controls on an operator console to manipulate input devices. When surgeons and / or other medical personnel operate various controls at the operator console, commands are forwarded from the operator console to the patient-side device, and one or more end effectors and / or surgical instruments are mounted to the patient-side device. In this way, surgeons and / or other medical personnel can use end effectors and / or surgical instruments to perform one or more routines on patients. Depending on the desired routine and / or the surgical instrument used, the desired routine can be performed partially or completely using remote operation under the control of the surgeon and / or medical personnel and / or performed under semi-autonomous control, in which the surgical instrument can perform a series of operations based on one or more activation actions performed by the surgeon and / or other medical personnel.

[0007] Whether manually actuated, teleoperated, or semi-autonomous, minimally invasive surgical instruments can be used in a variety of surgeries and / or routines and can have a variety of configurations. Many such instruments include an end effector mounted at the distal end of a shaft, which can be mounted to the distal end of an articulated arm. In many surgical scenarios, the shaft can be configured to be inserted (e.g., laparoscopically, thoracoscopically, and / or the like) through an opening (e.g., a body wall incision, a natural orifice, and / or the like) to reach a remote surgical site.

[0008] End effectors of different designs and / or configurations can be used to perform different tasks, routines, and functions to allow surgeons and / or other medical personnel to perform any of a variety of surgical routines. Examples include, but are not limited to, cauterization, excision, suturing, cutting, stapling, fusing, sealing, etc., and / or combinations thereof. Thus, the end effector can include various components and / or combinations of components to perform these surgical routines.

[0009] According to the goal of minimally invasive routines, the size of the end effector is generally kept small. One method of keeping the size of the end effector small is to achieve actuation of the end effector through the use of one or more inputs at the proximal end of the surgical instrument, wherein the proximal end is generally located outside the patient's body. Various transmission components (such as gears, levers, pulleys, cables, rods, belts, bands and / or the like) can then be used to transmit the action from the one or more inputs along the axis of the surgical instrument and actuate the end effector. In the case of a computer-assisted teleoperated medical device with a suitable surgical instrument, the transmission mechanism at the proximal end of the instrument is directly or indirectly connected to one or more actuators disposed on the articulated arm of the patient-side device or patient-side cart through other transmission components, such as various motors, solenoids, servos, movable actuators, hydraulic devices, pneumatic devices and / or the like. The (multiple) actuators receive control signals generated in response to user commands provided by the main controller and provide inputs including forces and / or torques at the proximal end of the transmission mechanism to the instrument; the various transmission elements ultimately transmit to actuate the end effector at the distal end of the transmission mechanism.

[0010] Because the size of the end effector is typically small, the end effector may have a limited stiffness, which may make the end effector susceptible to bending and / or extension during some grasping, clamping and / or stapling operations. Operating the instrument at a target speed subject to simple limitations on the amount of applied torque and / or force applied to the transmission mechanism can often result in grasping, clamping and / or stapling operations with failed operations, or uneven speed distributions due to tissue variations in space or time, and different operation steps, such as different force application phases to staple tissue in a stapling operation.

[0011] Therefore, it is desirable to have improved methods and systems for the operation of surgical instruments, such as grasping, clamping and / or stapling instruments.In some examples, it may be desirable to reduce the amount of bending and / or extension of an instrument without unacceptably slowing down the use of the instrument. Summary of the invention

[0012] According to some embodiments, a surgical instrument for use with a computer-assisted medical device includes an end effector at a distal end of the instrument, an actuator, and one or more drive mechanisms for coupling a force or torque from the actuator to the end effector. To perform an operation with the instrument, the computer-assisted medical device is configured to set a velocity set point of the actuator to an initial velocity, monitor a force or torque applied by the actuator, reduce the velocity set point when the applied force or torque is above a first threshold, increase the velocity set point when the applied force or torque is below a second threshold, reduce the velocity set point to zero when the applied force or torque is above a maximum threshold, and drive the actuator based on the velocity set point. The first threshold and the second threshold are below the maximum threshold.

[0013] According to some embodiments, a surgical instrument for use with a computer-assisted medical device includes an end effector at the distal end of the instrument, an actuator, and one or more drive mechanisms for coupling a force or torque from the actuator to the end effector. In order to perform an operation with the instrument, the computer-assisted medical device is configured to operate the end effector according to a state machine by driving the actuator according to a speed set point. The state machine includes a first clamping state, a second clamping state, and a waiting state. In the first clamping state, the speed set point of the actuator is set to a first speed. In the second clamping state, the speed set point of the actuator is set to a second speed lower than the first speed. In the waiting state, the speed set point is set to zero. When the force or torque applied by the actuator is above a first threshold, the state machine transitions from the first clamping state to the second clamping state. When the force or torque applied by the actuator is above a maximum threshold higher than the first threshold, the state machine transitions from the second clamping state to the waiting state. When the force or torque applied by the actuator is below the second threshold, the state machine transitions from the second clamping state to the first clamping state.

[0014] According to some embodiments, a method of operating a surgical instrument for use with a computer-assisted medical device includes using one or more processors to perform operations. The operations include setting a velocity set point of an actuator to an initial velocity, measuring a force or torque applied by the actuator, decreasing the velocity set point when the applied force or torque is above a first threshold, increasing the velocity set point when the applied force or torque is below a second threshold, decreasing the velocity set point to zero when the applied force or torque is above a maximum threshold, and using the actuator to drive one or more degrees of freedom of an end effector of the surgical instrument. The first threshold and the second threshold are below the maximum threshold.

[0015] According to some embodiments, a non-transitory machine-readable medium includes a plurality of machine-readable instructions that, when executed by one or more processors associated with a computer-assisted medical device, are suitable for causing the one or more processors to perform a method. The method includes setting a velocity set point of an actuator to an initial velocity and measuring a force or torque applied by the actuator. When the applied force or torque is above a first threshold, the method further includes reducing the velocity set point. When the applied force or torque is below a second threshold, the method further includes increasing the velocity set point. When the applied force or torque is above a maximum threshold, the method further includes reducing the velocity set point to zero. And the method further includes using the actuator to drive one or more degrees of freedom of an end effector of a surgical instrument. The first threshold and the second threshold are below the maximum threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a simplified diagram of a computer-assisted system according to some embodiments.

[0017] Figure 2 A simplified diagram illustrating a minimally invasive surgical instrument according to some embodiments.

[0018] FIG. 3A to FIG. 3D According to some embodiments Figure 2 Simplified diagram of the end effector.

[0019] Figure 4 is a simplified diagram of a state machine for operating an end effector according to some embodiments.

[0020] Figure 5 is a simplified diagram of the velocity-torque profile of an end effector according to some embodiments.

[0021] Figure 6 is a simplified diagram of a method for performing a stapling and cutting operation according to some embodiments.

[0022] In the drawings, elements with the same reference numerals have the same or similar functions. DETAILED DESCRIPTION

[0023] In the following description, the specific details of some embodiments of the present disclosure are described. However, it should be clear to those skilled in the art that some embodiments can be practiced without some or all of these specific details. The specific embodiments disclosed herein are intended to be illustrative and not restrictive. It will be appreciated by those skilled in the art that, although not specifically described herein, other elements may also be within the scope and spirit of the present disclosure. In addition, in order to avoid unnecessary repetition, unless specifically described otherwise or if one or more features shown and described in conjunction with an embodiment will make other embodiments inoperative, the one or more features may be incorporated into other embodiments.

[0024] Although the following description focuses primarily on embodiments of combined grasping, stapling, and cutting surgical instruments, those skilled in the art will appreciate that the variable speed methods and mechanisms of the present disclosure may be applied to other medical instruments, including surgical and non-surgical instruments. Also, although the following description generally discusses medical devices having robotic articulated arms (also referred to as "manipulators") for holding and actuating medical instruments, those skilled in the art will appreciate that the methods and mechanisms of the present disclosure may also be used with computer-assisted medical instruments that are separate from robotic or articulated arms, including medical instruments designed to be handheld or attached to non-articulated fixtures.

[0025] Figure 1 FIG. 1 is a simplified diagram of a computer-assisted system 100 according to some embodiments. Figure 1 , the computer-assisted system 100 includes a computer-assisted device 110 having one or more movable or articulated arms 120. Each of the one or more articulated arms 120 can support one or more instruments 130. In some examples, the computer-assisted device 110 can be consistent with a computer-assisted surgical device. The one or more articulated arms 120 can each provide support for a medical device 130, such as a surgical instrument, an imaging device, and / or the like. Examples of medical devices 130 include surgical instruments, imaging or sensing devices, and / or the like for interacting with tissue. In some examples, the instrument 130 can include an end effector that is capable of, but is not limited to, performing grasping, retraction, cauterization, excision, suturing, cutting, stapling, fusing, sealing, and the like, and / or combinations thereof.

[0026] The computer-assisted device 110 may be further coupled to an operator workstation (not shown) which may include one or more master controls for operating the computer-assisted device 110, the one or more articulated arms 120, and / or the instrument 130. In some examples, the one or more master controls may include master manipulators, levers, pedals, switches, keys, knobs, triggers, and / or the like. In some embodiments, the computer-assisted device 110 and the operator workstation may correspond to the da Vinci® Surgical System sold by Intuitive Surgical, Inc. of Sunnyvale, California. In some embodiments, computer-assisted surgical devices having other configurations, fewer or more articulated arms, and / or the like may be used with computer-assisted system 100.

[0027] The computer aided device 110 is coupled to the control unit 140 via an interface. The interface may be wired and / or wireless, and may include one or more cables, optical fibers, connectors, and / or buses, and may additionally include one or more networks having one or more network switches and / or routing devices. The operation of the control unit 140 is controlled by a processor 150. And although the control unit 140 is shown as having only one processor 150, it should be understood that the processor 150 may represent one or more central processing units, multi-core processors, microprocessors, microcontrollers, digital signal processors, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and / or the like in the control unit 140. The control unit 140 may be implemented as a stand-alone subsystem and / or a board attached to a computing device, or as a virtual machine. In some embodiments, the control unit 140 may be included as part of an operator workstation, and / or operate separately from the operator workstation but in cooperation with the operator workstation.

[0028] The memory 160 may be used to store software executed by the control unit 140 and / or one or more data structures used during operation of the control unit 140. The memory 160 may include one or more types of machine-readable media. Some common forms of machine-readable media may include floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tapes, any other physical media with patterns of holes, RAM, PROMs, EPROMs, FLASH-EPROMs, any other memory chips or cartridges, and / or any other media from which a processor or computer is suitable for reading.

[0029] like Figure 1As shown in , the memory 160 contains a control application 170, which can be used to support autonomous, semi-autonomous and / or teleoperation control of the computer-assisted device 110. The control application 170 can include one or more application programming interfaces (APIs) for receiving position, motion, force, torque and / or other sensor information from the computer-assisted device 110, the articulated arm 120 and / or the instrument 130, for exchanging position, motion, force, torque and / or collision avoidance information with other control units related to other devices, and / or for planning and / or assisting in planning the motion of the computer-assisted device 110, the articulated arm 120 and / or the instrument 130. In some examples, the control application 170 additionally supports autonomous, semi-autonomous and / or teleoperation control of the instrument 130 during the surgical routine. And although the control application 170 is depicted as a software application, the control application 170 can alternatively be implemented using hardware, software and / or a combination of hardware and software.

[0030] In some embodiments, the computer-assisted system 100 may be found in an operating room and / or interventional room. And although the computer-assisted system 100 includes only one computer-assisted device 110 having two articulated arms 120 and corresponding instruments 130, it should be understood by those skilled in the art that the computer-assisted system 100 may include any number of computer-assisted devices having articulated arms and / or instruments of similar and / or different designs than the computer-assisted device 110. In some examples, each of the computer-assisted devices may include fewer or more articulated arms and / or instruments.

[0031] Figure 2 A simplified diagram of a minimally invasive surgical instrument 200 is shown according to some embodiments. In some embodiments, the surgical instrument 200 may be used with Figure 1 Any device in the device 130 is consistent with. Figure 2 The directions “proximal” and “distal” depicted in and as used herein help describe the relative orientation and location of the components of surgical instrument 200. Distal generally refers to elements in a direction along the kinematic chain away from a user or machine holding instrument 200, a base of a computer-assisted device (such as computer-assisted device 110) for holding instrument 200, and / or elements closest to a surgical working site in the intended operational use of surgical instrument 200. Proximal generally refers to elements in a direction along the kinematic chain closer to a base of a computer-assisted device, a user or machine holding instrument 200, and / or one of the articulated arms of a computer-assisted device for holding instrument 200.

[0032] like Figure 2As shown in , surgical instrument 200 includes an elongated shaft 210 that couples an end effector 220 located at the distal end of the shaft 210 to where the surgical instrument 200 is mounted to an articulated arm and / or computer-assisted device at the proximal end of the shaft 210. Depending on the particular routine for which surgical instrument 200 is to be used, shaft 210 may be inserted through an opening in a patient's body (e.g., a body wall incision, a natural orifice, and / or the like) so as to place end effector 220 proximate to a remote surgical site located within the patient's anatomy. Figure 2 As further shown in FIG. 1 , the end effector 220 is generally consistent with a dual-jaw clamp-type end effector, which in some embodiments may additionally include a cutting and / or stapling mechanism, as described below with reference to FIG. FIG. 3A to FIG. 3D However, one skilled in the art will appreciate that different surgical instruments 200 having different end effectors 220 (eg, end effectors having fasteners instead of staples) are possible and may be consistent with the embodiments of surgical instruments 200 as described elsewhere herein.

[0033] Surgical instruments, such as surgical instrument 200 having end effector 220, typically use multiple degrees of freedom (DOF) during their operation. Depending on the configuration of surgical instrument 200 and the articulated arm and / or the computer-assisted device to which the articulated arm is mounted, various DOFs that can be used to position, orient, and / or manipulate end effector 220 are possible. In some examples, shaft 210 can be inserted in a distal direction and / or withdrawn in a proximal direction to provide an insertion DOF that can be used to control the depth at which end effector 220 is placed within the patient's anatomy. In some examples, shaft 210 can be rotated about its longitudinal axis to provide a roll DOF that is used to rotate end effector 220. In some examples, additional flexibility in the position and / or orientation of end effector 220 can be provided by one or more joints and / or linkages located proximate to shaft 210 and surgical instrument 200, such as joints and linkages of articulated arm 120. In some examples, an optional articulated wrist 230 can be used to couple the end effector 220 to the distal end of the shaft 210. In some examples, the articulated wrist 230 can optionally include one or more rotational joints, such as one or more roll, pitch, or yaw joints that can provide one or more "roll," "pitch," and "yaw" DOFs, respectively, which can be used to control the orientation of the end effector 220 relative to the longitudinal axis of the shaft 210. In some examples, the one or more rotational joints can include a pitch and yaw joint; a roll, pitch, and yaw joint; a roll, pitch, and roll joint; and / or the like. In some examples, the end effector 220 additionally includes a clamping DOF for controlling the opening and closing of the jaws of the end effector 220, and / or an activation DOF for controlling the extension, retraction, and / or operation of the stapling and cutting mechanisms, as described in more detail below.

[0034] The surgical instrument 200 further includes a drive system 240 located at the proximal end of the shaft 210. The drive system 240 includes one or more components for introducing forces and / or torques to the surgical instrument 200, which can be used to manipulate the various DOFs supported by the surgical instrument 200. In some examples, the drive system 240 can optionally include one or more motors, solenoids, servos, activated actuators, hydraulic devices, pneumatic devices, and / or the like that operate based on signals received from a control unit, such as Figure 1The control unit 140 of the present invention may include one or more current, voltage, pulse width modulated waveforms, and / or the like. In some examples, the drive system 240 may optionally include one or more shafts, gears, pulleys, rods, belts, and / or the like, which may be coupled to corresponding motors, solenoids, servos, activation actuators, hydraulic devices, pneumatic devices, and / or the like as part of an articulated arm on which the surgical instrument 200 is mounted, such as any of the articulated arms 120. In some examples, one or more drive inputs (e.g., shafts, gears, pulleys, rods, belts, and / or the like) are used to receive forces and / or torques from motors, solenoids, servos, activation actuators, hydraulic devices, pneumatic devices, and / or the like, and apply those forces and / or torques to adjust various DOFs of the surgical instrument 200. In this discussion, both "force" and "torque" are sometimes used separately to indicate linear force, rotational torque, and / or both, when applicable.

[0035] In some embodiments, one or more drive mechanisms 250 are used to transmit the force and / or torque generated by the drive system 240 and / or received by the drive system along the shaft 210 from the drive system 240 to various joints and / or elements of the surgical instrument 200 located away from the drive system 240. In some examples, the one or more drive mechanisms 250 may optionally include one or more gears, levers, pulleys, cables, rods, belts, and / or the like. In some examples, the shaft 210 is hollow, and the drive mechanisms 250 are transmitted from the drive system 240 along the inside of the shaft 210 to the corresponding DOF in the end effector 220 and / or the articulated wrist 230. In some examples, each of the drive mechanisms 250 may optionally be a cable disposed inside a hollow sheath or lumen in a Bowden wire configuration. In some examples, the inside of the cable and / or lumen may optionally be coated with a low friction coating, such as polytetrafluoroethylene (PTFE) and / or the like. In some examples, when the proximal end of each of the cables is pulled and / or pushed inside the drive system 240, for example by winding and / or unwinding around a capstan or shaft, the distal end of the cables moves accordingly and applies appropriate forces and / or torques to adjust one or more of the DOFs of the end effector 220, the articulated wrist 230, and / or the surgical instrument 200.

[0036] FIG. 3A to FIG. 3D FIG. 2 is a simplified diagram of an end effector 220 according to some embodiments. FIG. 3A to FIG. 3D, the distal end or end effector 220 of the surgical instrument 200 includes mechanisms for jaw closure, tissue stapling, and tissue cutting. And although the end effector 220 is shown and described as having one fixed and one movable jaw, it should be understood by those skilled in the art that the distal end of the surgical instrument 200 can be modified to use two movable jaws. It should be further understood that although the following description is in the context of a grasping, stapling, and cutting instrument that simultaneously grasps, staples, and cuts tissue, the aspects so described can be applicable to instruments with or without cutting features, instruments that support fusion rather than stapling, and / or the like.

[0037] Figure 3A A cut-away side view of the end effector 220 prior to actuation is shown, such that the jaws of the end effector 220 are shown in an open position. As shown, the end effector includes a substantially fixed first jaw 310. The jaw 310 is designed to receive a replaceable staple cartridge 320 that holds a plurality of staples 330 and a plurality of staple pushers 335. The staple cartridge 320 is designed to be replaceable, such that the end effector 220 can be reused by removing the first staple cartridge 320 after one or more of the staples 330 have been used and replacing the first staple cartridge with a second staple cartridge 320 having a new set of staples 330 that can be used to perform another surgical routine. Figure 3B 320 is shown in a top view. Figure 3B As depicted in , the staple cartridge includes six rows of staple slots 340 through which staples 330 can be applied to the captured tissue after actuation of the end effector 220. The rows of staple slots 340 include three rows on each side of the slot 350, which is described in further detail below. Placing the staples 330 on both sides of the slot 350 allows the staples 330 to be applied to both sides of the desired cut line so as to close the tissue on both sides of the cut line. The rows of staple slots 340 are also offset relative to each other to provide a more complete tissue closure along both sides of the cut line. And although the staple cartridge 320 is shown as having six rows of offset staple slots 340, each row having six staple slots 340 of uniform size, it should be understood by those skilled in the art that fewer or more rows of staple slots with fewer or more staples, staple slots of varying sizes, and staple slots of varying patterns are possible.

[0038] like Figure 3A As further shown in FIG. 1 , the end effector 220 further includes a second jaw 360 movable about a pivot point (not shown) near its proximal end. In the context of a stapling instrument, the second jaw 360 may alternatively be referred to as an anvil 360. Figure 3A, the anvil 360 includes a transition edge 370 that is configured such that upon initial actuation of the end effector 220, the gap between the anvil 360 and the jaw 310 is rapidly reduced until tissue is captured between the anvil 360 and the jaw 310. Actuation of the end effector 220 is accomplished by movement of a reciprocating element 380 from the proximal end of the end effector 220 to the distal end of the end effector 220. The reciprocating element 380 is coupled to the distal end of one or more of the drive mechanisms 250.

[0039] The reciprocating element 380 includes a sled 382 and a flange 384, wherein a cutting blade 386 is coupled between the sled 382 and the flange 384. The reciprocating element 380 has a generally I-beam cross-sectional shape, such as in Figure 3D 340. The end effector 220 is shown in a cutaway end view of the end effector 220 shown in FIG. When the end effector 220 is actuated for stapling, the slide 382 is advanced along the jaws 310 and the staple cartridge 320 therein as the reciprocating element 380 is pushed by the drive mechanism 250. The slide 382 includes a wedge-shaped front end or distal end so that when the front end encounters each of the staple pushers 335, the front end pushes the staple pushers 335 against the corresponding staple 330. This action causes each of the staples 330 to be ejected through a corresponding staple slot in the staple slot 340. Although the slide 382 is shown as having a single wedge at its leading edge, the slide 382 may alternatively include a separate wedge for each of the rows of staples 330 in the staple cartridge 320 and the staple pushers 335. In addition, each of the separate wedges may alternatively be staggered relative to each other in the direction in which the slide 382 moves. In some embodiments, staple pusher 335 is optional and the leading edge of slideway 382 directly pushes staples 330. As slideway 382 advances along jaws 310 and staple cartridge 320 therein, flange 384 advances along anvil 360 therein. When the leading distal end of flange 384 encounters transition edge 370, flange 384 causes initial rapid closing of the gap between anvil 360 and jaws 310. Cutting blade 386 is positioned slightly proximal to the distal end of slideway 382 and flange 384 so that the cutting of any captured tissue lags behind the ejection of staples 330 along both sides of the cutting line. When reciprocating element 380 is actuated, cutting blade 386 advances along slot 350 and corresponding slot 355 located in anvil 360.

[0040] Figure 3C and 3DThe cut-away side view and cut-away end view of the end effector 220 are shown respectively after the end effector 220 has been fully actuated. As shown, the reciprocating element 380, together with the slide rail 382, ​​the flange 384, and the cutting blade 386, are located at the distal end of the end effector 220. When the leading edge of the slide rail 382 encounters each of the staple pushers 335, the slide rail pushes the staple pushers 335, which in turn pushes the staples 330 upward through the corresponding staple slots 340, wherein the staples are pressed through any captured tissue and into the face of the anvil 360, wherein the staples are bent as shown in the figure. Figure 3C The final shape is shown in FIG. The gap between the anvil 360 and the jaws 310 is maintained by the presence of the flange 384 in the anvil 360. In this way, the reciprocating element 380, the slide 382, ​​the flange 384, and the cutting blade 386 are all components of the end effector 220 that move in response to an applied force or torque provided by the actuator controlling the movement of the reciprocating element 380.

[0041] The operation of the end effector 220 is subject to several practical considerations when the end effector is actuated. First, the reciprocating element 380 can be moved distally at a high speed level, where very little force or torque must be applied to the drive mechanism 250 for advancing the reciprocating element 380. However, when the flange 384 begins to encounter the leading edge 370 and the gap between the anvil 360 and the jaws 310 begins to close rapidly, any tissue captured between the anvil 360 and the jaws 310 begins to resist further movement of the reciprocating element 380. To compensate for this, the drive system 240 applies additional force and / or torque to the drive mechanism 250 to maintain the speed of the reciprocating element 380. Monitoring of the force and / or torque is performed to ensure that the applied force and / or torque is maintained at a reasonable upper limit to avoid unacceptable bending and / or extension of the jaws 310 and / or anvil 360; damage to the end effector 220, the drive system 240 and / or the drive mechanism 250; and / or damage to the captured tissue. Second, when tissue is captured between the anvil 360 and the jaws 310, the tissue typically begins to dry out as fluid is pushed out of the tissue due to the pressure of the capture. As long as the speed of the reciprocating element 380 is properly controlled, the amount of force and / or torque used to continue to advance the reciprocating element 380 can be generally managed within reasonable limits for compliant tissue. Third, additional force and / or torque is typically required so that the slide 382 can push each of the staple pushers 335 against the staples 330 so that the staples 330 are pushed through the captured tissue and / or the cutting blades 386 can cut the captured tissue while maintaining the desired speed of the reciprocating element 380. This additional force and / or torque can vary significantly as the nature of the tissue being stapled changes, previously applied staple lines are crossed, and / or the like.

[0042] In order to achieve smooth operation of the end effector 220, it is generally desirable to actuate the reciprocating element 380 at a constant speed throughout the initial contact with the tissue, the ejection of the stapler 330, and the cutting of the captured and stapled tissue. In some embodiments, this is performed by: monitoring and / or limiting the applied force and / or torque to reduce and / or avoid unacceptable bending and / or extension of the jaws 310 and / or the anvil 305; damage to the end effector 220, the drive system 240, and / or the drive mechanism 250; and / or damage to the captured tissue. One method is to operate the end effector 220 using a constant speed set point that is subject to the maximum force and / or torque limit of the drive system 240. The constant speed set point can be selected to provide a balance between the speed of the operation and the risk of encountering a force and / or torque limit. In some examples, the constant speed set point can be optionally adjustable based on the type of tissue being captured, stapled, and clamped (e.g., by an operator). In some embodiments and / or under certain operating conditions, a particular speed set point and / or range of speed set points may cause non-optimal operation of the end effector 220 due to a constant speed set point that is too low; cause uneven operation due to constant encountering of force and / or torque limits, which causes the reciprocating element 380 to decelerate and accelerate in a potentially unstable manner; and / or the like.

[0043] Improved performance and smoother operation of the end effector 220 is possible by using a velocity profile of the reciprocating element 380 that is adapted based on the force and / or torque applied by the drive system 240 and the drive mechanism 250. For example, when the force and / or torque begins to increase, the velocity of the reciprocating element 380 is reduced in a controlled manner, and when the force and / or torque begins to decrease, the velocity of the reciprocating element 380 is increased in a controlled manner. In this manner, smoother operation of the end effector 220 is achieved as compared to relying on a single force and / or torque limit to indirectly slow the velocity of the reciprocating element 380. For example, deceleration when the force and / or torque threshold is below the maximum force and / or torque limit can produce an operation with fewer starts and stops because the reciprocating element 380 is at rest at the maximum force and / or torque limit.

[0044] According to some embodiments, other techniques may be used to adjust the speed. For example, when the force and / or torque passes a threshold amount, the speed of the reciprocating element 380 may be set to the currently detected speed of the reciprocating element 380 and / or a speed set point slightly below the currently detected speed.

[0045] Return to reference Figure 3A, also shown is an arrow 390 indicating the direction of travel of the reciprocating element 380 during actuation of an example stapling process. A set of dashed lines 392, 394, 396, 398 indicate specific positions reached by the distal end of the slide 382 during the stapling operation. When the distal end of the slide 382 is between the positions indicated by dashed lines 392 and 394, the stapler is in a "grasping" state (also referred to as a "grasping stage"), in which the first jaw 310 and the second jaw 360 are closed to a roughly parallel posture and can gently grasp the patient's tissue. When the distal end of the slide 382 reaches the position indicated by dashed line 394, the stapler transitions from the grasping state to a "clamping but not firing" state (also referred to as a "clamping but not firing stage"), in which the first jaw 310 and the second jaw 360 are held in close enough proximity to apply sufficient clamping force to the patient's tissue. This clamped but unfired state can provide some pre-stab compression of the patient's tissue and help flatten the tissue to increase the chances of a successful stapling operation.

[0046] When the distal end of the slide 382 reaches the position indicated by the dashed line 396, the stapler has transitioned from the clamped but not fired state to the "fired" state (also referred to as the "fired phase"), wherein the slide 382 pushes the various ones of the staple pushers 335 against the corresponding staples 330 and fires these staples 330 through the staple slots 340. The stapling process ends when the distal end of the slide 382 has reached its target at the position indicated by the dashed line 398. This fired state may also be referred to as a "clamped" state, which is separate from the clamped but not fired state.

[0047] According to some embodiments, the applied force or torque can be monitored during the firing state, the clamped but not fired state, the grasping state, and / or a combination of any two or three of these states. In some examples, in the firing state, the applied force or torque can be monitored, and processes such as those discussed in the present disclosure are performed. In some examples, in the firing state and in the fully or partially clamped but not fired state, the applied force or torque can be monitored, and processes such as those discussed in the present invention are performed. In some examples, different force or torque limit thresholds and / or the use of other parameters can be used for the firing state and the clamped but not fired state.

[0048] According to some embodiments, feedback may be provided to the surgeon and / or other medical personnel during the stapling operation. In some examples, a control unit in a computer-assisted system (e.g., computer-assisted system 100) may estimate the likelihood of a successful stapling process in a clamped but unfired state and provide this estimate to a user by any suitable method, including by visual display, auditory feedback, and / or the like. In some examples, this feedback may be provided when the stapling process may be easily reversed, so that staples are not spent during a certain routine and staples may not be used anywhere else. In some embodiments, the computer-assisted system will inhibit the start of the fired state until the likelihood of a successful stapling is measured to be sufficiently high.

[0049] In some embodiments, surgical instrument 200 and / or an associated computer-assisted system (e.g., computer-assisted system 100) is configured with a user interface that enables the three states to be distinguished for the operator. For example, some embodiments provide different controls for changing states through different combinations of knobs, buttons, switches, pedals, and other input devices. In some examples, for a remotely operated computer-assisted system, the computer-assisted system may be configured to: (1) command entry into a grasping state in response to sensing a squeeze input on a master manipulator input device associated with an activated stapler instrument, such as by commanding the slide 382 to move at a grasping speed to a position corresponding to dashed line 392, (2) command entry into a clamping but not firing state in response to depression of the first pedal, such as by commanding the slide 382 to move at a clamping but not firing speed to a position corresponding to dashed line 394, (3) command entry into a firing state and remain in the firing state, such as by commanding the slide 382 to move at a firing speed to a position beyond dashed line 396 to dashed line 398 at the distal end of the end effector 220. Some embodiments may also be configured with timeouts such that a squeeze motion, a first pedal depression, and / or a second pedal depression generates a command for an associated state after an associated predetermined period of time has elapsed through the squeeze motion, the first pedal depression, and / or the second pedal depression. In some embodiments, the surgical instrument 200 or an associated computer-assisted system (e.g., computer-assisted system 100) is configured with a user interface that combines the "grasp" state and the "hold but not fire" state, or the "hold but not fire" and "fire" states from a user control perspective. In some embodiments, a single switch or pedal is provided for the operator to indicate entering the grasp state and transitioning to the grip but not fire state. In some embodiments, a single switch or pedal is provided for the operator to indicate entering the grip but not fire state and transitioning to the fire state.

[0050] Figure 44 is a simplified diagram of a state machine 400 for operating an end effector according to some embodiments. One or more of the states 410 to 490 of the state machine 400 may be implemented at least in part in the form of executable code stored on a non-transitory tangible machine-readable medium, which, when executed by one or more processors (e.g., processor 150 in control unit 140), may cause one or more processors to implement one or more of the states 410 to 490. In some embodiments, the state machine 400 may be implemented by an application, such as control application 170. In some embodiments, the state machine 400 may be used to constrain and / or limit a velocity set point of an actuator based on a torque applied by an actuator, such as an actuator that controls movement of the reciprocating element 380. In some embodiments, the torque of the actuator is monitored while the state machine 400 is operating. In some embodiments, state transitions between states 410 to 490 may occur when the indicated state transition occurs, or may alternatively occur at periodic intervals based on the execution of a control loop that implements the state machine 400.

[0051] The state machine 400 begins in a start state 410. Based on guidance and / or commands by an operator, such as a surgeon, via activation of one or more controls, inputs, and / or the like, the operation of the end effector transitions to a pre-clamp state 420. In the pre-clamp state 420, a speed set point for an actuator (e.g., a speed set point for an actuator that propels the reciprocating element 380) is set to an initial speed v0. In some examples, the speed v0 may optionally be consistent with a maximum allowable speed of the actuator. In some embodiments, the operation of the end effector remains in the pre-clamp state 420 until the actuator has moved a minimum distance or reaches an initial position (e.g., a position corresponding to dashed line 394). In some examples, the minimum distance may correspond to a position where initial grasping of tissue occurs, such as a moment before and / or a moment after the distal end of the flange 384 encounters the transition edge 370 and the gap between the anvil 360 and the jaws 310 begins to close. In some embodiments, this initial grasping of tissue is combined with Figure 3A The "grasp" state discussed above and / or the pre-grasp state that may be applicable just before the grasp state are associated with the grasp state. In some embodiments, this initial grasp of the tissue is combined with Figure 3A The "grasp" state discussed is associated with some or all of the "grip but not fired" state. When the torque of the actuator exceeds the maximum torque τ before reaching the minimum distance max , the state machine 400 transitions to the Failure state 490. The state machine 400 may indicate the Failure state 490 to the human operator visually, audibly, or via some other feedback method. When the torque of the actuator does not exceed the maximum torque, the state machine 400 transitions to the Initial Clamping state 430.

[0052] In the initial clamping state 430, the speed set point of the actuator is set to the initial clamping speed v1. The control of the actuator then continues at the speed v1 until the target position is reached (e.g., when the reciprocating element 380 has been advanced to the distal end of the end effector 220) or the torque threshold τ1 is reached. The torque τ1 is lower than the maximum torque τ max . In some examples, velocity v1 may optionally be the same velocity as initial velocity v0. State machine 400 may indicate success state 480 to a human operator visually, audibly, and / or via some other feedback method. When the target position is reached, state machine 400 transitions to success state 480. When the torque of the actuator exceeds torque τ1 before reaching the target position, state machine 400 transitions to first slow clamping state 440.

[0053] In the first slow clamping state 440, the speed set point of the actuator is set to a speed v2 that is lower than the speed v1. Control of the actuator then continues at the speed v2. While in the first slow clamping state 440, the torque of the actuator is additionally monitored to see whether the torque is increasing or decreasing. When the torque of the actuator decreases to a torque τ2 that is less than the torque τ1 (e.g., 5% to 20% lower than τ1 and / or in the 1-3 N-m range below τ1), the state machine 400 transitions back to the initial clamping state 430, where the speed set point of the actuator is increased back to the speed v1. The amount by which the torque τ2 is lower than the torque τ1 can be set to introduce hysteresis in the speed control of the actuator to avoid excessive jitter of the speed set point of the actuator. When the torque of the actuator increases to a torque τ3, the state machine 400 transitions to the second slow clamping state 450. The torque τ3 is lower than the maximum torque τ max , but is typically higher than torque τ1, so that the increased torque continues to result in a lower speed set point for the actuator. When the target position is reached, the state machine 400 transitions to the success state 480.

[0054] In the second slow clamping state 450, the speed set point of the actuator is set to a speed v3 that is lower than the speed v2. Control of the actuator then continues at the speed v3. While in the second slow clamping state 450, the torque of the actuator is additionally monitored to see whether the torque is increasing or decreasing. When the torque of the actuator decreases to a torque τ4 that is lower than the torque τ3, the state machine 400 transitions back to the first slow clamping state 440, in which the speed of the actuator is increased. The amount by which the torque τ4 is lower than the torque τ3 can be set to introduce hysteresis in the speed control of the actuator to avoid excessive jitter in the speed set point of the actuator. When the torque of the actuator increases to a torque τ5, the state machine 400 transitions to the waiting state 460. The torque τ5 can optionally be compared to the maximum torque τ maxSame or lower than the maximum torque, but typically higher than torque τ3, so that the increased torque continues to result in a lower speed set point for the actuator. When the target position is reached, the state machine 400 transitions to the success state 480 .

[0055] In the waiting state 460, the state machine 400 suspends operation for a predetermined time period (also referred to as a "pause period"). In order to suspend operation in the waiting state 460, the state machine 400 can pause the actuator by setting the speed set point of the actuator to zero to stop the movement of the actuator. In some examples, setting the speed set point of the actuator to zero allows additional time in which the captured tissue can further dry out. In some examples, the state machine 400 remains in the waiting state for a predetermined time period to provide a temporary pause from the actuation of the stapler. In some examples, the predetermined time period can be optionally implemented using a hardware and / or software timer. After the predetermined time period times out, the state machine 400 automatically transitions to the trying state 470.

[0056] In the attempt state 470, the actuator is attempted to be moved. Each time an attempt is attempted, the attempt counter increases. In some examples, the attempt may optionally include setting the speed set point of the actuator back to speed v3 or another speed value. When the movement of the actuator is possible and the torque of the actuator remains below the torque τ6 lower than the torque τ5, the attempt counter is reset to zero and the state machine 400 transitions back to the second slow clamping state 450, wherein the speed set point of the actuator increases back to speed v3. The amount of torque τ6 lower than the torque τ5 can be set to introduce hysteresis in the speed control of the actuator to avoid excessive jitter of the speed set point of the actuator. When the torque of the actuator remains above the torque τ6 during the attempt state 460, the state machine 400 returns to the waiting state 460 to wait for an additional amount of time. The state machine 400 can be configured so that the state machine can only transition to the waiting state 460 after the attempt time period has passed, the minimum attempt distance has been achieved, and / or both. When the attempt counter exceeds the maximum number of attempts, the state machine 400 transitions to the failure state 490.

[0057] In the success state 480, successful stapling and cutting are detected, and control of the actuators is optionally reversed, causing the jaws of the end effector to open with a corresponding release of the grasped tissue. FIG. 3A to FIG. 3D In some examples, reversing the actuator includes pulling the reciprocating element 380 in a proximal direction, so that the slide 382 is pulled out of the jaws 310 and the staple cartridge 320, the flange 384 is pulled out of the anvil 360 to allow the anvil 360 to pivot open, and the cutting blade 386 is pulled back to a safe position, such as a storage position. In some examples, the success of the stapling and cutting operation can optionally be reported to the operator using an audible and / or visual alarm.

[0058] In the failed state 490, it is detected that the stapling and cutting operation failed to complete because the actuator was unable to reach the target location. FIG. 3A to FIG. 3D In the example of 490, this occurs when the reciprocating element 380 is unable to advance to the distal end of the jaws 310 and the anvil 360. When in the failure state 490, an audible and / or visual alarm indicating the failure of the stapling and cutting operation is reported to the operator. In some examples, the reversal of the actuator can be attempted automatically by the state machine or at the explicit command of the operator.

[0059] As discussed above and further emphasized here, Figure 4 Only examples are provided, and the examples should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. In some embodiments, properties other than torque of the end effector and actuator may be monitored alternatively and cause the state transitions described above. In some examples, the force applied by the actuator instead of torque may be monitored. In some embodiments, the initial clamping state 430 and the pre-clamping state 420 may be optionally combined into a single state. In some embodiments, the second slow clamping state 450 may be removed so that the state machine 400 transitions from the first slow clamping state 400 to the waiting state 460 when the torque of the actuator is higher than the torque τ3. In some embodiments, the first slow clamping state 440 and the second slow clamping state 450 are removed so that the process transitions from the initial clamping state 430 to the waiting state 460 when the torque of the actuator is higher than the torque τ1. In some embodiments, depending on how many steps are expected in the speed-torque profile of the end effector, additional slow clamping states may be optionally added between the second slow clamping state 450 and the waiting state 460.

[0060] In some embodiments, one or more techniques may optionally be used to reduce the effects of temporary transients in the application of torque thresholds. In some examples, a state transition of the state machine 400 occurs when the applied torque remains above or below the corresponding torque threshold for a predetermined time period. In some examples, the predetermined time period may optionally be different for the torque threshold for decreasing the speed set point and the torque threshold for increasing the speed set point. In some examples, a state transition of the state machine 400 occurs when the average value of the applied torque is above or below the corresponding torque threshold. In some examples, exponential smoothing is used to calculate the average value. In some examples, the applied torque is low pass filtered.

[0061] Figure 5 FIG. 5 is a simplified diagram of the speed-torque profile 500 of the end effector of FIG. 3 according to some embodiments. Figure 5As shown in , the speed-torque profile 500 includes multiple speed set values ​​based on the monitored torque changes. In some examples, the speed-torque profile 500 is consistent with the speed set point implemented by the state machine 400. In the speed-torque profile 500, the speed set point of the actuator (e.g., the actuator of the end effector 220) is set to the speed v1 until the torque applied by the actuator exceeds the torque τ1. Once the torque τ1 is exceeded, the speed set point is reduced to the speed v2. The speed of the actuator is then controlled at the speed v2 until the torque applied by the actuator exceeds the torque τ3. Once the torque τ3 is exceeded, the speed set point is reduced to the speed v3. The speed of the actuator is then controlled at the speed v3 until the torque applied by the actuator exceeds the torque τ5. Once the torque τ5 is exceeded, the speed set point is reduced to zero. The speed-torque profile 500 is additionally implemented using hysteresis such that the speed set point of the actuator is not increased back to speeds v3, v2, and v1 until the torque of the actuator drops below torques τ6, τ4, and τ2, respectively, where torques τ6, τ4, and τ2 are set below torques τ5, τ3, and τ1, respectively.

[0062] As discussed above and further emphasized here, Figure 5 These are examples only and should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. In some embodiments, properties of the end effector and actuator other than torque may be used in the velocity profile. In some examples, actual force passing through the actuator may be used rather than torque. In some embodiments, fewer and / or more than three steps may optionally be used in the speed-torque profile. In some embodiments, the speed-torque profile 500 may optionally be implemented without hysteresis by setting τ2 equal to τ1, setting τ4 equal to τ3, and setting τ6 equal to τ5. In some embodiments, a smoothed speed-torque profile with or without hysteresis may optionally be used instead. Figure 5 In some examples, the speed-torque profile may optionally be linear, contain a series of s-shaped smooth steps, and / or other monotonic profiles, where the speed set point is calculated as a function of torque. In some embodiments, the torque used to determine the speed set point may optionally be an average torque, a low-pass filtered torque, and / or the like.

[0063] Figure 6600 is a simplified diagram of a method 600 for performing stapling and cutting operations according to some embodiments. One or more of the processes 605 to 650 of the method 600 may be implemented at least in part in the form of executable code stored on a non-transitory tangible machine-readable medium. This executable code, when run by one or more processors (e.g., the processor 150 in the control unit 140), causes one or more processors to perform one or more of the processes 605 to 650. In some embodiments, the method 600 may be executed by an application, such as the control application 170. In some embodiments, the method 600 may be used to limit the speed of an actuator for actuating a reciprocating element (e.g., the reciprocating element 380) based on the torque applied by the actuator. In some embodiments, the stapling and cutting operations of the method 600 may be performed according to the state machine 400 and / or the speed-torque profile 500. In some embodiments, the tests of processes 615, 620, and 630 may be performed simultaneously and / or in any order.

[0064] At process 605, the end effector is actuated (also referred to as "fired"). An end effector (e.g., end effector 220) is fired by causing an actuator (e.g., an actuator in drive system 240) to apply a torque for controlling at least one DOF of the end effector. In some examples, the actuator is controlled by sending one or more signals (e.g., current, voltage, pulse width modulated signal, and / or the like) to the actuator. The actual effect of the firing of the end effector depends on the design, use, and purpose of the end effector. In some examples, the firing of the end effector is initiated by setting a velocity set point for the actuator, such as setting the velocity set point to velocity v0 during the pre-grip state 420. Using Figure 2 and FIG. 3A to FIG. 3D In the example of the embodiment of the present invention, the actuator applies a force to the drive mechanism 250, which causes the reciprocating element 380 to move toward the distal end of the end effector 220. This in turn causes a reduction in the gap between the anvil 360 and the jaws 310, so that tissue is captured, the staples 330 are forced through the captured tissue by the slide rails 382 acting on the staple pusher 335, and the cutting blade 386 cuts the captured tissue. The activation of the end effector continues until the success or failure of the activation is determined and / or the activation is interrupted by the operator.

[0065] At process 610, the applied torque is monitored. Using one or more sensors and / or control algorithms, the torque applied by the actuator is monitored when the end effector is activated. For example, when the actuator is a motor, the current applied to the motor can be monitored and used to determine the torque applied by the motor.

[0066] At process 615, it is determined whether the end effector is at the target position. Using one or more sensors, the position of the actuator and / or the position of a detectable position on the end effector is monitored. In some examples, the sensor can measure the rotation angle of the drive shaft of the actuator. In some examples, the one or more sensors can include shaft encoders, Hall effect sensors, and / or the like. FIG. 3A to FIG. 3D In some examples, the target position corresponds to the movement of the reciprocating element 380 to the distal end of the end effector 220 so that all staples 330 have been ejected through the captured tissue and the cutting blade 386 has cut through the captured tissue. When the target position is reached, the operation of the end effector is considered successful and the speed set point is set to zero. In some examples, the operator of the system is also notified via an audible and / or visual alarm. In some examples, success is consistent with the success state 480. When the target position has not yet been reached, the process 620 begins and the monitored torque is compared to one or more torque thresholds.

[0067] At process 620, it is determined whether the applied torque is above a first torque threshold. The applied torque monitored during process 610 is compared to the first torque threshold to determine whether the actuator is applying more torque to the end effector than desired. In some examples, the first torque threshold may optionally vary depending on the current speed set point. Figure 4 and Figure 5 In the example of , the first torque threshold corresponds to one or more of torques τ1, τ3, and / or τ5. When the applied torque is above the first torque threshold, the speed set point is reduced using process 625. When the applied torque is not above the first threshold, the torque is compared to the second torque threshold using process 630.

[0068] At process 625, the speed set point is reduced. When the applied torque is above the first threshold, the speed set point of the actuator is reduced to allow additional time for the captured tissue to further dry out, slow the ejection of one or more staples, and / or the like. In some examples, the speed set point can be reduced by a fixed amount, a percentage amount, according to a speed-torque profile, and / or the like. Figure 4 and Figure 5 In the example of FIG60 , the speed set point is reduced to v2, v3, or zero depending on the previous speed set point and / or the first torque threshold used during process 620. In some examples, the reduction in the speed set point coincides with a state transition from the initial clamping state 430 to the first slow clamping state 440, a state transition from the first slow clamping state 440 to the second slow clamping state 450, and / or a state transition from the second slow clamping state 450 to the waiting state 460. After the speed set point is reduced, the speed set point is tested to determine whether the speed set point is reduced to zero using process 640.

[0069] At process 630, it is determined whether the applied torque is below a second threshold. The applied torque monitored during process 610 is compared to the second torque threshold to determine whether the actuator can be accelerated. In some examples, the second torque threshold is set lower than the first torque threshold to provide hysteresis in the speed set point. In some examples, the second torque threshold is optionally varied depending on the current speed set point. Figure 4 and Figure 5 In the example of , the second torque threshold corresponds to one or more of torques τ2, τ4, and / or τ6. When the applied torque is below the second torque threshold, the speed set point is increased using process 635. When the applied torque is not below the second threshold, the torque is monitored again using process 610.

[0070] At process 635, the speed set point is increased. When the applied torque is below the second threshold, the speed set point of the actuator is increased to allow faster operation of the end effector. In some examples, the speed set point can be increased by a fixed amount (e.g., 0.1 to 2 mm / sec), a percentage amount (e.g., 5% to 25%), according to a speed-torque profile, and / or the like. In some examples, when the speed is at the maximum set point, the speed set point is not further increased during process 635. Figure 4 and Figure 5 In the example of FIG60 , the speed set point is increased to v1, v2, or v3 depending on the previous speed set point and / or the second torque threshold used during process 630. In some examples, the increase in the speed set point coincides with a state transition from the attempting state 470 to the second slow clamping state 450, a state transition from the second slow clamping state 450 to the first slow clamping state 440, and / or a state transition from the first slow clamping state 440 to the initial clamping state 430. After the speed set point is increased, the torque is again monitored using process 610.

[0071] At process 640, it is determined whether the speed set point is zero. When the speed set point reaches zero, a delay is introduced using process 645. When the speed set point is not yet zero, the torque is again monitored using process 610.

[0072] At process 645, a wait (also referred to as a "pause") occurs. When the velocity set point reaches zero, activation of the end effector is delayed for a predetermined period of time (e.g., 1 to 10 seconds). In some examples, the predetermined period of time is tracked using a hardware and / or software timer. Figure 4 In the example of , process 645 corresponds to the wait state 460. After the delay has expired, process 650 is used to test the operation of the end effector.

[0073] At process 650, a determination is made as to whether operation of the end effector can continue. The speed set point is set to a non-zero value, such as the speed set point value prior to the last execution of process 625, and the torque applied by the actuator is monitored. Figure 4 In the example of , process 650 corresponds to the attempt state 470. When the torque applied by the actuator continues to be above the maximum torque threshold (e.g., the first torque threshold used in the last execution of process 620), the activation of the end effector is considered to have failed and the speed set point is set to zero. In some examples, the activation of the end effector can be optionally reversed, and / or one or more audio and / or visual alarms can be optionally provided to the operator. When movement at a non-zero speed set point occurs without detecting excessive applied torque, the speed set point is maintained and the monitoring of torque continues through process 610.

[0074] As discussed above and further emphasized here, Figure 6 Merely by way of example, the examples should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. In some embodiments, properties of the end effector and actuator other than torque may be monitored during process 610 and tested during processes 620 and 630. In some embodiments, the waiting of process 645 and / or the testing of process 650 may be repeated once, twice, or more times before declaring a failure. In this way, method 600 may pause the actuator multiple times and indicate a failure after a predetermined number of actuator pauses have occurred. In some examples, the number of repetitions is tracked using a hardware and / or software counter.

[0075] In some embodiments, one or more techniques may optionally be used to reduce the effects of temporary transients in the application of torque thresholds. In some examples, the comparison of the applied torque to the first torque threshold and the second torque threshold, respectively, in processes 620 and 630 determines whether the applied torque remains above or below the first torque threshold and the second torque threshold for a predetermined time period. In some examples, the predetermined time period may optionally be different for the first torque threshold and the second torque threshold. In some examples, the monitoring of the applied torque in process 610 includes averaging the applied torque. In some examples, averaging includes using exponential smoothing. In some examples, the monitoring of the applied torque in process 610 includes low pass filtering the applied torque.

[0076] Some examples of control units (e.g., control unit 140) may include non-transitory tangible machine-readable media containing executable code that, when executed by one or more processors (e.g., processor 150), may cause the one or more processors to implement the states of state machine 400, implement the implementation of speed-torque profile 500, and / or perform the processes of method 600. Some common forms of machine-readable media that may include the implementation of state machine 400, the implementation of speed-torque profile 500, and / or the processes of method 600 are, for example, floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tape, any other physical media having a pattern of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, and / or any other media from which a processor or computer is suitable for reading.

[0077] Although illustrative embodiments have been shown and described, a wide range of modifications, changes and substitutions are contemplated in the foregoing disclosure, and in some instances, some features of the embodiments may be employed without the corresponding use of other features. Those skilled in the art will recognize many variations, alternatives and modifications. Accordingly, the scope of the present invention should be limited only by the appended claims, and the claims are intended to be construed broadly in a manner consistent with the scope of the embodiments disclosed herein.

Claims

1. A computer-aided system comprising: Actuator; An apparatus, comprising: an end effector at a distal end of the instrument; and one or more drive mechanisms for coupling force or torque from the actuator to the end effector; and one or more processors, wherein to perform an operation with the instrument, the one or more processors are configured to operate the end effector according to a state machine; in: The state machine includes a first clamping state, a second clamping state and a waiting state; In the first clamping state, the speed set point of the actuator is set to a first speed; In the second clamping state, the speed set point of the actuator is set to a second speed lower than the first speed; The state machine transitions from the first clamped state to the second clamped state when the force or torque applied by the actuator is above a first threshold; The state machine transitions from the second clamped state to the first clamped state when the force or torque applied by the actuator is below a second threshold; and The state machine transitions from the second clamping state to the waiting state when the force or torque applied by the actuator is above a maximum threshold that is higher than the first threshold. 2 . The computer-assisted system of claim 1 , wherein the operation comprises one or more of grasping, stapling, and cutting.

3. The computer-assisted system of claim 1, wherein the second threshold is equal to or lower than the first threshold.

4. The computer-assisted system of claim 1, wherein the first speed and the second speed are determined according to a speed profile.

5. The computer-assisted system of claim 4, wherein the velocity profile is monotonic.

6. The computer-assisted system of any one of claims 1-5, wherein the first speed and the second speed are determined based on an applied force or torque.

7. The computer-assisted system of any one of claims 1-5, wherein the first threshold and the second threshold vary based on an applied force or torque.

8. The computer-assisted system of any one of claims 1-5, wherein the one or more processors are further configured to indicate success upon reaching a target location.

9. A non-transitory machine-readable medium comprising a plurality of machine-readable instructions which, when executed by one or more processors associated with a computer-assisted system, are adapted to cause the one or more processors to perform a method comprising: operating an end effector according to a state machine, the state machine comprising a first clamping state, a second clamping state, and a waiting state, wherein in the first clamping state a speed set point of an actuator is set to a first speed, and in the second clamping state the speed set point of the actuator is set to a second speed lower than the first speed; transitioning the state machine from the first clamped state to the second clamped state when the force or torque applied by the actuator is above a first threshold; transitioning the state machine from the second clamped state to the first clamped state when the force or torque applied by the actuator is below a second threshold; as well as The state machine is transitioned from the second clamping state to the waiting state when the force or torque applied by the actuator is above a maximum threshold that is higher than the first threshold. 10 . The non-transitory machine-readable medium of claim 9 , wherein the second threshold is equal to or lower than the first threshold. 11 . The non-transitory machine-readable medium of claim 9 , wherein the first speed and the second speed are determined according to a speed profile.

12. The non-transitory machine-readable medium of any one of claims 9 to 11, wherein: The first speed and the second speed are determined based on an applied force or torque; or The first threshold and the second threshold vary based on the applied force or torque.

13. A computer-aided system comprising: Actuator; An apparatus, comprising: an end effector at a distal end of the instrument; and one or more drive mechanisms for coupling force or torque from the actuator to the end effector; and one or more processors, wherein in order to perform operations with the apparatus, the one or more processors are configured to: setting a speed set point of the actuator to an initial speed; driving the actuator based on the speed set point; monitoring a force or torque applied by the actuator; When the applied force or torque is above the first threshold: Decrease the speed set point, and driving the actuator based on a reduced speed set point; When the applied force or torque is below a second threshold, increasing the speed set point; and driving the actuator based on an increased speed set point; and When the applied force or torque is above a maximum threshold: Decrease the speed set point to zero, Wait for the scheduled time period, setting the speed setpoint to a non-zero value, and driving the actuator based on the non-zero speed set point; Wherein the first threshold is lower than the maximum threshold and the second threshold is lower than the first threshold.

14. The computer-assisted system of claim 13, wherein after said waiting, said one or more processors are further configured to: determining whether the applied force or torque continues to be above the maximum threshold; and Failure is indicated when the applied force or torque continues to be above the maximum threshold.

15. The computer-assisted system of claim 13, wherein after said waiting, said one or more processors are further configured to: determining whether the applied force or torque continues to be above the maximum threshold; and While the applied force or torque continues to be above the maximum threshold, the speed set point is set back to zero and wait again.

16. The computer-assisted system of claim 15, wherein the one or more processors are further configured to indicate a failure after a predetermined number of waiting cycles if the applied force or torque continues to be above the maximum threshold.

17. The computer-assisted system of claim 13, wherein after said waiting, said one or more processors are further configured to: reverse actuation of said end effector if said applied force or torque continues to be above said maximum threshold.

18. A non-transitory machine-readable medium comprising a plurality of machine-readable instructions which, when executed by one or more processors associated with a computer-assisted system, are adapted to cause the one or more processors to perform a method comprising: setting a speed set point of the actuator to an initial speed; driving the actuator based on the speed set point; monitoring a force or torque applied by the actuator; When the applied force or torque is above the first threshold: Decrease the speed set point, and driving the actuator based on a reduced speed set point; When the applied force or torque is below a second threshold, increasing the speed set point; and driving the actuator based on an increased speed set point; as well as When the applied force or torque is above a maximum threshold: Decrease the speed set point to zero, Wait for the scheduled time period, setting the speed setpoint to a non-zero value, and driving the actuator based on the non-zero speed set point; Wherein the first threshold is lower than the maximum threshold and the second threshold is lower than the first threshold.

19. The non-transitory machine-readable medium of claim 18, wherein the method further comprises, after the waiting, determining whether the applied force or torque continues to be above the maximum threshold; and Failure is indicated when the applied force or torque continues to be above the maximum threshold.

20. The non-transitory machine-readable medium of claim 18, wherein the method further comprises, after the waiting, determining whether the applied force or torque continues to be above the maximum threshold; and While the applied force or torque continues to be above the maximum threshold, the speed set point is set back to zero and wait again.

21. The non-transitory machine-readable medium of claim 18, wherein the method further comprises, after the waiting, reversing actuation of an end effector actuated by the actuator when the applied force or torque continues to be above the maximum threshold.

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