Systems and methods for controlling an instrument

Abstract

Systems and methods of controlling an instrument include first and second actuators configured to actuate degrees of freedom (DOFs) in first and second directions with respective transmission mechanisms and control units. The control units are configured to: determine positions of the first and second actuators; determine actuation commands based on the positions of the first and second actuators and a desired state of the DOFs; determine respective actuation levels of the first and second actuators so as to maintain tension in the transmission mechanisms above respective minimum tensions by utilizing a model based on force or torque commands, minimum tensions, and the first and second actuator positions; and command actuation of the first and second actuators at the respective actuation levels. The model compensates for external disturbances on the DOFs and dynamics of the first and second actuators.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 001,046, filed March 27, 2020, entitled "Systems and Method of Controlling Instruments," the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to the operation of equipment having instruments, and more specifically to controlling at least one degree of freedom of the instruments. Background Technology

[0004] More and more devices are being replaced by computer-aided electronic devices. This is especially true in industrial, recreational, educational, and other settings. As an example in medicine, modern hospitals have a vast array of electronic equipment in operating rooms, interventional rooms, intensive care units, emergency rooms, and more. For instance, glass and mercury thermometers are being replaced by electronic thermometers, intravenous drip lines now include electronic monitors and flow regulators, and traditional handheld surgical instruments and other medical devices are being replaced by computer-aided medical devices.

[0005] These computer-aided devices can be used to perform operations and / or procedures on materials (such as a patient's body tissue) located in a workspace. By using numerous computer-aided devices, an operator (e.g., a surgeon in the medical example) can remotely operate the devices using one or more controls on an operator console. As the operator manipulates the various controls at the operator console, commands are transmitted from the operator console to devices within or near the workspace, to which one or more end effectors and / or instruments are attached. This enables the operator to perform one or more procedures on materials or objects in the workspace using the end effectors and / or instruments. Depending on the desired procedure and / or the instrument used, the desired procedure can be performed partially or entirely under the operator's remote control and / or semi-autonomous control, where, under semi-autonomous control, the instrument can perform or modify the sequence of operations based on one or more activation actions by the operator.

[0006] Different designs and / or configurations of instruments can be used to perform different tasks, procedures, and / or functions, allowing an operator to perform any of a variety of procedures. Computer-assisted instruments, whether manually actuated, teleoperated actuated, and / or semi-autonomously driven, can be used for a variety of operations and / or procedures and can have a variety of configurations. Many such instruments include an end effector mounted at a distal end of a shaft, which can be mounted to a distal end of a repositionable arm. In many operational scenarios, the shaft can be configured to be inserted (e.g., laparoscopically, thoracoscopically, etc.) through an opening (e.g., a body wall incision, a natural orifice, an access port, etc.) to reach a remote site within a working area. In some instruments, an articulating wrist mechanism can be mounted to a distal end of the shaft of the instrument to support the end effector, where the articulating wrist provides the ability to change the orientation of the end effector relative to a longitudinal axis of the shaft. Examples of such instruments include, but are not limited to, cauterization, ablation, suturing, cutting, stapling, fusing, sealing, etc., and / or combinations thereof. Accordingly, instruments can include a variety of components and / or combinations of components to perform these procedures.

[0007] When access to a working space is limited, the size and / or strength of an instrument can be limited. As one medical example, when a computer-assisted device is used to perform a minimally invasive surgical procedure, the instrument can have to fit through a body orifice and / or body wall incision that is kept as small as possible to reduce the impact on the patient. In another example, when a working space is limited (e.g., it is hazardous, climate controlled, sterile, etc.), access to the working space can be controlled through one or more orifices that can be reduced in size. Consistent with the goal of accessing a working space with limited access, the size of the end effector is typically kept as small as possible while still allowing it to perform its intended tasks. One way to keep the size of the end effector small is by using one or more inputs at a proximal end of the instrument, which can be located outside of the working space, to accomplish the actuation of the end effector. Various gears, levers, pulleys, cables, rods, belts, chains, sprockets, and / or the like can then be used to transmit the motions from the one or more inputs along the shaft of the instrument and actuate the degrees of freedom (DOFs) of the end effector. For example, a force or torque transmission mechanism at the proximal end of the instrument interfaces with various actuators (e.g., motors, solenoids, servos, hydraulic devices, pneumatic devices, etc.) provided via a drive unit on a repositionable arm of a computer-assisted device located within or near the working space. These actuators typically receive control signals from a control module and provide inputs in the form of force and / or torque at the proximal end of the force or torque transmission mechanism, which various gears, levers, pulleys, cables, rods, belts, chains, sprockets, and / or the like ultimately convey to actuate the DOFs of the end effector at the distal end of the force or torque transmission mechanism.

[0008] When the force or torque transmission mechanism has sufficient rigidity to apply force or torque to the DOF in both directions, a single actuator in the drive unit can actuate the DOF in both directions. However, in this case, the force or torque transmission mechanism is typically larger than desired and / or larger than the dimensions that can be accommodated, such as body wall cutouts, natural orifices, or access ports.

[0009] Therefore, improved methods and systems for controlling instruments using remotely positioned actuators are desired. Summary of the Invention

[0010] Consistent with some embodiments, a computer-aided device includes a first actuator configured to actuate a degree of freedom of an instrument in a first direction using a first force or torque transmission mechanism, a second actuator configured to actuate the degree of freedom in a second direction using a second force or torque transmission mechanism, and a control unit coupled to the first and second actuators. The second direction is at least partially opposite to the first direction. The control unit is configured to: determine a first position of the first actuator; determine a second position of the second actuator; determine a force or torque command based on the first position, the second position, and a desired state of the degree of freedom; determine a first actuation level of the first actuator and a second actuation level of the second actuator to maintain a first tension in the first force or torque transmission mechanism above a first minimum tension and maintain a second tension in the second force or torque transmission mechanism above a second minimum tension by utilizing a model based on the force or torque command, a first minimum tension, a second minimum tension, the first position, and the second position; and command the actuation of the first actuator to be at the first actuation level and the actuation of the second actuator to be at the second actuation level. The model compensates for external disturbances in the degree of freedom and the dynamics of the first and second actuators.

[0011] Consistent with some embodiments, a method performed by a control unit of a computer-aided device includes: determining a first position of a first actuator, the first actuator being configured to actuate a degree of freedom of a device in a first direction using a first force or torque transmission mechanism; determining a second position of a second actuator, the second actuator being configured to actuate the degree of freedom in a second direction using a second force or torque transmission mechanism; determining a force or torque command based on the first position, the second position, and a desired state of the degree of freedom; determining a first actuation level of the first actuator and a second actuation level of the second actuator to maintain a first tension in the first force or torque transmission mechanism above a first minimum tension and a second tension in the second force or torque transmission mechanism above a second minimum tension by utilizing a model based on the force or torque command, a first minimum tension and a second minimum tension, the first position and the second position; and commanding actuation of the first actuator to be at the first actuation level and actuation of the second actuator to be at the second actuation level. The second direction is at least partially opposite to the first direction. The model compensates for external disturbances in the degree of freedom and the dynamics of the first and second actuators.

[0012] Consistent with 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 adapted to cause one or more processors to perform any of the methods described herein. Attached Figure Description

[0013] Figure 1 This is a simplified diagram of a computer-aided system according to some embodiments.

[0014] Figure 2 This is a simplified diagram of an apparatus according to some embodiments.

[0015] Figure 3 This is a simplified diagram of an apparatus according to some embodiments.

[0016] Figure 4 This is a simplified diagram of the distal end of an apparatus according to some embodiments.

[0017] Figure 5A and Figure 5B This is a simplified diagram of the distal end of an apparatus according to some embodiments.

[0018] Figure 6 This is a simplified diagram of a DOF control system for an instrument, according to some embodiments.

[0019] Figure 7 This is a simplified diagram of a free-body diagram of a DOF for an instrument according to some embodiments.

[0020] Figure 8 According to some embodiments, it is used for Figure 7A simplified diagram of the DOF control system of the instrument.

[0021] Figure 9 This is a simplified diagram of a method for controlling an apparatus according to some embodiments.

[0022] In the accompanying drawings, elements with the same name have the same or similar functions. Detailed Implementation

[0023] The illustrations in this specification and the accompanying drawings, which depict aspects, embodiments, implementation methods, or modules of the invention, should not be considered limiting—the claims define the protected invention. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of this specification and the claims. In some cases, well-known circuits, structures, or techniques have not been shown or described in detail so as not to obscure the invention. Identical numbers in two or more figures represent the same or similar elements.

[0024] In this specification, specific details are set forth to describe some embodiments consistent with this disclosure. Numerous specific details are set forth to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are illustrative and not restrictive. Those skilled in the art will recognize other elements within the scope and spirit of this disclosure, although not specifically described herein. Furthermore, to avoid unnecessary repetition, one or more features shown and described in connection with one embodiment may be incorporated into other embodiments unless otherwise specifically described or if one or more features would render the embodiment inoperable.

[0025] Furthermore, the terminology used in this specification is not intended to limit the invention. For example, spatially related terms—such as “below,” “under,” “lower,” “above,” “over,” “near,” “far”, etc.—are used to describe the relationship of an element or feature to another element or feature shown in the figures. These spatially related terms are intended to cover the different positions (i.e., orientations) and orientations (i.e., rotational layouts) of elements shown in the figures, or their operation, as well as their positions and orientations. For example, if the contents of a figure are flipped, an element described as “below” or “under” other elements or features would be “above” or “over” other elements or features. Thus, the exemplary term “below” can cover both above and below positions and orientations. Devices may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially related descriptors used herein are interpreted accordingly. Similarly, descriptions of movement along and around various axes include various specific element positions and orientations. Furthermore, unless the context otherwise requires, the singular forms “a,” “an,” and “the” are also intended to include the plural forms. Furthermore, the terms "comprising," "including," "containing," etc., specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or components. Components described as coupled may be electrically or mechanically directly coupled, or they may be indirectly coupled through one or more intermediate components.

[0026] Elements described in detail with reference to one embodiment, implementation, or module may be included in other embodiments, implementations, or modules that are not specifically shown or described therein, as long as practicable. For example, if an element is described in detail with reference to one embodiment and not with reference to a second embodiment, that element may still be claimed to be included in the second embodiment. Therefore, to avoid unnecessary repetition in the following description, one or more elements shown and described in association with one embodiment, implementation, or application may be incorporated into other embodiments, implementations, or aspects unless otherwise specifically described, unless one or more elements would render one embodiment or implementation inoperable, or unless two or more elements provide conflicting functionality.

[0027] In some cases, well-known methods, processes, components, and circuits have not been described in detail to avoid unnecessarily obscuring certain aspects of some embodiments.

[0028] This disclosure describes various devices, elements, and portions of computer-aided devices and components based on their state in three-dimensional space. As used herein, the term "position" refers to the location of an element or a portion of an element in three-dimensional space (e.g., three translational degrees of freedom along the Cartesian x, y, and z coordinates). As used herein, the term "orientation" refers to the rotational arrangement of an element or a portion of an element (three rotational degrees of freedom—e.g., roll, pitch, and yaw). As used herein, the term "shape" refers to a set position or orientation measured along the element. As used herein and for devices with repositionable arms, the term "proximal" refers to a direction along its kinematic chain toward the base of the computer-aided device, while "distal" refers to a direction along the kinematic chain away from the base.

[0029] The present disclosure is described with reference to computer-aided systems and apparatus, which may include remotely operated, remotely controlled, autonomous, semi-autonomous, robotic, and / or similar systems and apparatus. Furthermore, some aspects of the present disclosure are described based on embodiments using surgical systems, such as the da... (The sentence is incomplete and requires more context to translate accurately). Surgical system. However, those skilled in the art will understand that the inventive aspects disclosed herein can be embodied and implemented in various ways, including robotic and (if applicable) non-robotic embodiments and implementations. Regarding da The implementation of the surgical system is merely exemplary and should not be construed as limiting the scope of the inventive aspects disclosed herein. For example, the techniques described with reference to surgical instruments and methods can be used in other contexts. Therefore, the instruments, systems, and methods described herein can be used with respect to the human body, animals, parts of human or animal anatomy, industrial systems, general-purpose robots, or remote operating systems. As further examples, the instruments, systems, and methods described herein can be used for non-medical purposes, including industrial applications, general robotic applications, sensing or manipulating non-tissue artifacts, cosmetic enhancements, imaging of human or animal anatomy, collecting data from human or animal anatomy, establishing or dismantling systems, training medical or non-medical personnel, etc. Additional example applications include procedures for removing tissue from human or animal anatomy (without returning the human or animal anatomy) and procedures for human or animal cadavers. Furthermore, these techniques can also be used in medical treatment or diagnostic procedures, with or without surgical aspects.

[0030] Figure 1 This is a simplified diagram of a computer-aided system 100 according to some embodiments. For example... Figure 1As shown, the computer-aided system 100 includes a computer-aided device 110 having one or more movable or repositionable arms 120. Each of the one or more repositionable arms 120 can support one or more instruments 130. In some examples, the computer-aided device 110 may be consistent with a computer-aided surgical device. The one or more repositionable arms 120 may each provide support for an instrument 130 such as a surgical instrument, imaging device, etc. In some examples, the instrument 130 may include an end effector capable of, but not limited to, performing, grasping, retracting, cauterizing, ablating, suturing, cutting, patching, fusing, sealing, etc., and / or combinations thereof.

[0031] The computer-assisted device 110 may be further coupled to an operator workstation (not shown), which may include one or more input controls for operating the computer-assisted device 110, one or more repositionable arms 120, and / or instruments 130. In some examples, the one or more input controls may include a master manipulator, lever, pedal, switch, key, knob, trigger, etc. In some embodiments, the computer-assisted device 110 and the operator workstation may correspond to the da commercially available from Intuitive Surgical, Inc. of Sunnyvale, California, USA. Surgical system. In some embodiments, computer-assisted surgical devices with other configurations, fewer or more repositionable arms and / or similar features may be used with computer-assisted system 100.

[0032] Computer-aided device 110 is coupled to control unit 140 via an interface. This interface may include one or more cables, optical fibers, connectors, and / or buses, and may also include one or more networks with one or more network switching and / or routing devices. Control unit 140 includes a processor 150 coupled to memory 160. Operation of control unit 140 is controlled by processor 150. While control unit 140 is shown as having only one processor 150, it should be understood that processor 150 may represent one or more central processing units, multi-core processors, microprocessors, microcontrollers, digital signal processors, field-programmable gate arrays (FPGAs), graphics processing units (GPUs), application-specific integrated circuits (ASICs), tensor processing units (TPUs), etc., within control unit 140. Control unit 140 may be implemented as a separate subsystem and / or board added to a computing device or implemented as a virtual machine. In some embodiments, control unit 140 may be included as part of an operator workstation and / or operate independently of but in coordination with an operator workstation.

[0033] Memory 160 may be used to store software executed by control unit 140 and / or one or more data structures used during operation of control unit 140. 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 tape, any other magnetic media, CD-ROMs, any other optical media, punched cards, paper tape, any other physical media with a perforated pattern, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cassette memory, and / or any other media suitable for reading by a processor or computer.

[0034] like Figure 1 As shown, memory 160 includes a control module 170 that can be used to support autonomous, semi-autonomous, and / or remote operation control of computer-assisted device 110. Control module 170 may include one or more application programming interfaces (APIs) for receiving position, motion, force, torque, and / or other sensor information from computer-assisted device 110, repositionable arm 120, and / or instrument 130; exchanging position, motion, force, torque, and / or collision avoidance information with other control units regarding other devices; and / or planning and / or assisting in planning the motion of computer-assisted device 110, repositionable arm 120, and / or instrument 130. In some examples, control module 170 may further support autonomous, semi-autonomous, and / or remote operation control of instrument 130 during procedures such as surgical procedures. And while control module 170 is described as a software application, control module 170 may be implemented using hardware, software, and / or a combination of hardware and software.

[0035] In some medical embodiments, the computer-assisted system 100 may be found in an operating room and / or interventional kit. And while the computer-assisted system 100 comprises only one computer-assisted device 110 with two repositionable arms 120 and corresponding instruments 130, it should be understood that the computer-assisted system 100 may include any number of computer-assisted devices with repositionable arms and / or instruments, having a design similar to and / or different from that of the computer-assisted device 110. In some examples, each computer-assisted device may include fewer or more repositionable arms and / or instruments.

[0036] Figure 2 This is a simplified diagram of a device 200 according to some embodiments. In some embodiments, the device 200 may be... Figure 1 Any instrument consistent with 130. For example... Figure 2The terms “proximal” and “distal”, as used herein, are used to describe the relative orientation and positioning of the components of instrument 200. Distal generally refers to elements further along the kinetic chain from the base of the computer-aided device (e.g., computer-aided device 110), and / or elements closer to the workspace during the intended operational use of instrument 200. Proximal generally refers to elements closer along the kinetic chain to the base of the computer-aided device and / or one of the repositionable arms of the computer-aided device.

[0037] like Figure 2 As shown, the instrument 200 includes a shaft 210 for coupling an end effector 220 located at the distal end of the shaft 210 to a position where the instrument 200 is mounted proximal to a repositionable arm and / or computer-aided device on the shaft 210. Depending on the specific procedure using the instrument 200, the shaft 210 can be inserted through an opening (e.g., a body wall incision, natural orifice, workspace port, etc.) to position the end effector 220 near a remote working site within a workspace (e.g., the patient's internal anatomy in the medical example). Figure 2 As further shown, the end effector 220 is generally consistent with a dual-jaw gripper type end effector, and in some embodiments, the end effector may also include a cutting and / or welding or sealing mechanism. However, it should be understood that different instruments 200 with different end effectors 220 are possible, including one, two, or any number of fingers with various shapes and sizes, and these designs may be consistent with embodiments of instrument 200.

[0038] An instrument (e.g., instrument 200 with end effector 220) typically moves along multiple degrees of freedom (DOFs) during operation of instrument 200. Depending on the configuration of instrument 200 and the repositionable arm and / or computer-aided device to which instrument 200 is mounted, various DOFs can be used to position, orient, and / or manipulate end effector 220. In some examples with an insertion DOF, the system configuration provides an insertion DOF by enabling axis 210 to insert or retract along an insertion axis relative to the proximal portion of instrument 200; in some other examples with an insertion DOF, it provides an insertion DOF by enabling the entire instrument 200 to translate along the insertion axis. In some examples with a roll DOF, the system configuration provides a roll degree of freedom for end effector 220 by enabling axis 210 to rotate about a longitudinal axis relative to the proximal portion of instrument 200; in some other examples with a roll DOF, it provides a roll DOF by enabling the entire instrument 200 to rotate about a longitudinal axis. In some examples, the device 200 includes a hinged wrist 230 coupled between the end effector 220 and the shaft 210. This hinged wrist 230 may include one or more joints, such as one or more rotary joints, prismatic joints, ball joints, or complex joints providing one or more pitch, yaw, or individual finger controls (e.g., for opening or closing the gripper device) DOFs. This wrist-supported DOF can be used to control the position or orientation of the end effector 220 relative to the longitudinal axis of the shaft 210. In some examples, the device 200 may also include a gripping DOF specifically for controlling the opening and closing of the grippers of the end effector 220, an activation DOF for controlling the extension, retraction, and / or operation of the cutting mechanism, or other DOFs.

[0039] The device 200 also 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 into the device 200, which can be used to manipulate various degrees of freedom (DOF) supported by the device 200. In some examples, the drive system 240 may include one or more actuators based on actuators from a control unit (e.g., Figure 1The control unit 140 operates by receiving signals. Examples of actuators include motors and solenoids powered by any suitable power source, including electric, hydraulic, pneumatic, etc. In some examples, the signals may include one or more current, voltage, pulse-width modulated waveforms, etc. In some examples, the drive system 240 may not include actuators but includes one or more transmission components removably coupled to a corresponding actuator that is part of a repositionable arm (e.g., any of the repositionable arms 120); such a drive system 240 can transmit and / or convert forces and / or torques from those actuators to apply these forces and / or torques and adjust various degrees of freedom (DOF) of the instrument 200. In some examples, the drive system 240 includes a combination of one or more actuators with one or more transmission components removably coupled to actuators external to the drive system 240. Examples of transmission components include shafts, gears, screws, pulleys, rods, belts, chains, sprockets, cables, etc.

[0040] In some embodiments, one or more force or torque transmission mechanisms 250 may be used to transmit forces and / or torques generated and / or received by the drive system 240 from the drive system 240 to various joints and / or elements of the device 200 located distal to the drive system 240. In some examples, one or more force or torque transmission mechanisms 250 may include one or more transmission components. In some examples, the shaft 210 may include one or more cavities, and one or more force or torque transmission mechanisms 250 deliver from the drive system 240 to the corresponding DOF in the end effector 220 and / or articulated wrist 230 within one or more cavities along the interior of the shaft 210.

[0041] In some embodiments, the DOF of the device 200 is controlled using a single actuator and a single force or torque transmission path between the actuator and the DOF. To support actuation of the DOF in both directions (e.g., clockwise and counterclockwise, insertion and retraction, translation to the left and right, etc.), the force or torque transmission mechanism in that transmission path between the actuator and the DOF is capable of applying force or torque to the DOF in both directions. Examples of such a force or torque transmission mechanism include a rod and a series of gears.

[0042] In some embodiments, a force or torque transmission mechanism reliably transmits force or torque in only one manner (e.g., many cables and belts can transmit tension rather than compression and can be used to provide pull rather than thrust). Such a force or torque transmission mechanism may be favored in specific applications for a variety of reasons, such as smaller size, lower cost, easier assembly, greater material availability, etc.

[0043] In some embodiments of those using force or torque transmission mechanisms that reliably transmit force or torque in only one manner, the transmission system itself may be designed to use a single actuator. For example, the transmission system may be configured such that the actuation of the actuator always supplies force or torque in a manner transmissible by the transmission mechanism. As a concrete example, when the actuator rotates the driven pulley clockwise or counterclockwise, and when the cable is configured to loop around a non-driven pulley on one side and around a pulley rotated by the actuator on the other side, the actuator applies tension to the cable. However, in this configuration, the cable is typically pre-tensioned; this pre-tensioning is intended to provide sufficient normal force between the pulley and the cable such that the friction between the cable and the pulley is sufficient to reliably transmit force or torque. This pre-tensioning increases the driving force required by the actuator and may lead to greater wear on the actuator, as well as on the cable, pulley, and other parts of the transmission system. Furthermore, this pretensioning may limit the material options for the drivetrain, for example, in some cases leading to the avoidance of certain plastics and / or composites, such as certain ultra-high molecular weight polyethylene (UHMWPE or UHMW) or high modulus polyethylene (HMPE) in certain situations.

[0044] In some other embodiments using a force or torque transmission mechanism that reliably transmits force or torque in only one manner, the system is configured to use two force or torque transmission paths to control the DOF. For example, two actuators in drive system 240 can be used to control the DOF in an antagonistic manner, such that one actuator is configured to actuate the DOF in a first direction and a second actuator is configured to actuate the DOF in a second direction at least partially opposite to the first direction. As a specific example, in one embodiment, a first cable is coupled to transmit force from the first actuator to pull the DOF in the first direction, while a second cable is coupled to transmit force from the second actuator to pull the DOF in the second direction; then, coordinated control of the two cables supports control of the DOF in both the first and second directions.

[0045] Figure 3 This is a simplified diagram of device 300 according to some embodiments. In some embodiments, device 300 is identical to device 200. Figure 3 As shown, the device 300 has a first DOF controlled by first and second actuators. Although the device 300 in Figure 3 The image shows only one DOF, but it is understood that device 300 may include one, two, or more DOFs. For example... Figure 3As shown, the device 300 includes a shaft 310 that couples an end effector 320 to a drive unit 340. The end effector 320 includes fingers 322 attached to a disk 324, such that the fingers 322 rotate together with the disk 324. The disk 324 is rotatable about an axis 326, thus providing rotational freedom for the fingers 322. The disk 324 is rotated by controlling a first force or torque transmission mechanism 351 and / or a second force or torque transmission mechanism 352. The first force or torque transmission mechanism 351 couples the disk 324 to a first actuator 341 to drive the disk 324 in a first direction of rotation. The second force or torque transmission mechanism 352 couples the disk 324 to a second actuator 342 to drive the disk 324 in a second direction of rotation opposite to the first direction of rotation. For ease of explanation, in Figure 3 In the example, the first actuator 341 and the second actuator 342 are shown as being within the drive unit 340. However, as described above, the first actuator 341 and the second actuator 342 can be located outside the device and coupled to the drive unit 340 using any number of force or torque transmission components.

[0046] Both the first actuator 341 and the second actuator 342 are located in the drive unit 340, and each of the first actuator 341 and the second actuator 342 may include a transmission system for transmitting the prime mover provided by the actuator to the force or torque transmission mechanisms 351, 352. As shown, the first actuator 341 provides a rotational prime mover about a first axis 361, and the second actuator 342 provides a rotational prime mover about a second axis 362. The finger 322 can be rotated clockwise by pulling the force or torque transmission mechanism 351 during movement, facilitating the movement of the force or torque transmission mechanism 352 or allowing the movement of the force or torque transmission mechanism 352 to follow. Similarly, the finger 322 can be rotated counterclockwise by pulling the force or torque transmission mechanism 352 during movement, facilitating the movement of the force or torque transmission mechanism 351 or allowing the movement of the force or torque transmission mechanism 351 to follow. Because actuators 341 and 342 typically do work to move finger 322 in opposite directions, this arrangement is sometimes referred to as antagonistic control.

[0047] Although Figure 3 The first actuator 341 and the second actuator 342 are depicted as rotating together with a single pulley; however, in other embodiments, the first actuator 341 and / or the second actuator 342 may be linear actuators with any number of transmission components, or both. Similarly, although Figure 3 Force or torque transmission mechanisms 351 and 352 are depicted as a single integral component (e.g., cable, belt, etc.), but in some embodiments, any number of components may form each of force or torque transmission mechanisms 351 and 352.

[0048] Figure 4 This is a simplified diagram of the distal portion of a device 400 according to some embodiments, showing a portion of the axis, wrist, and end effector of the device 400. In some embodiments, the device 400 is consistent with the device 200. The device 400 includes an end effector 420 coupled to the axis 410 via a hinged wrist 430. The end effector 420 includes a first finger 422 (also referred to as a first gripper 422) rotatable about an axis 426 and a second finger 424 (also referred to as a second gripper 424) rotatable about the axis 426. In some embodiments, the gripper 422 and the gripper 424 operate in a coordinated manner to produce different behaviors. In some examples, by moving jaws 422 and 424 relative to each other, such as by moving only jaw 422, only jaw 424, or both jaws 422 and 424 relative to wrist 430, the gap between jaws 422 and 424 can be reduced by rotating them toward each other; this produces a closing motion of jaws 422 and 424 and can be used, for example, to grip material. In some examples, by moving jaws 422 and 424 relative to each other, such as by moving only jaw 422, only jaw 424, or both jaws 422 and 424 relative to wrist 430, the gap between jaws 422 and 424 can be increased by rotating them away from each other; this produces an opening motion of jaws 422 and 424 and can be used, for example, to release gripped material. In some examples, the yaw of the end effector 420 relative to the wrist 430 can be changed by rotating the grippers 422, 424 in the same direction.

[0049] Figure 4 The diagram also shows force or torque transmission mechanisms for controlling the DOF of the end effector 420. For example, a first force or torque transmission mechanism 451 for controlling the first gripper 421 and a second force or torque transmission mechanism 452 for controlling the second gripper 424 are shown. Each of the force or torque transmission mechanisms 451 and 452 can be coupled to a drive unit at the proximal portion of the instrument 400 and is driven by one, two, or more actuators, such as in combination. Figure 3 As described.

[0050] The articulated wrist 430 includes a U-shaped clamp 432 and a pin 434, about which the end effector 420 can rotate relative to the U-shaped clamp 432 and the shaft 410. As shown, the articulated wrist 430 provides pitch (DOF) of the instrument 400. Force or torque transmission mechanisms 453 and 454 are used to articulate the pitch (DOF). Each of the force or torque transmission mechanisms 453 and 454 can be coupled to a drive unit at a proximal portion of the instrument 400 and is driven by one, two, or more actuators, such as in combination. Figure 3 As described.

[0051] In the illustrated example, each cable forming force or torque transmission mechanisms 451, 452, 453, 454 is wound around a corresponding pulley to provide an opposite force or torque transmission mechanism to force or torque transmission mechanisms 451, 452, 453, 454. In some examples, one or more separate cables form an opposite force or torque transmission mechanism for one or more force or torque transmission mechanisms 451, 452, 453, 454.

[0052] Although instrument 400 is in Figure 4 The portion depicted herein is shown as having three DOFs (clamp-release, yaw, and pitch), but it should be understood that the instrument 400 may include additional DOFs (additional yaw or pitch DOF along axis 410, roll DOF, etc.) that can be controlled using any of the methods described herein.

[0053] Figure 5A and Figure 5B This is a simplified diagram of the distal end of device 500 according to some embodiments. In some embodiments, device 500 is identical to device 200. Figure 5A and Figure 5B As shown, device 500 corresponds to a three-DOF device that can be controlled using four actuators. In some embodiments, device 500 is consistent with the device described in U.S. Patent No. 8,821,480, which is incorporated herein by reference.

[0054] As shown, the device 500 includes an end effector 520 connected to a shaft 510 via a hinged wrist 530. The end effector 520 includes a first gripper 522 rotatable about an axis 526 and a second gripper 524 also rotatable about the axis 526. By moving the grippers 522 and 524 relative to each other in a manner similar to that discussed with respect to device 400, it is possible to decrease or increase the separation 529 between the grippers 522 and 524. Similarly, similar to device 400, it is possible to change the yaw of the end effector 520 by rotating the grippers in the same direction. The hinged wrist 530 includes a U-shaped clamp 532 and a pin 534 about which the end effector 520 is rotatable.

[0055] existFigure 5A and Figure 5B The three DOFs (clamp-release, yaw, and pitch) of the device 500 shown are controlled using four force or torque transmission mechanisms 551-554. In some embodiments, each of the force or torque transmission mechanisms 551-554 is coupled to a drive unit at its respective proximal end, such that the force or torque transmission mechanism can be driven by one or more corresponding actuators. In some embodiments, with respect to... Figure 3 The force or torque transmission mechanisms 351 and 352 are consistent with the embodiments shown, and the force or torque transmission mechanisms 551-554 can be connected to the actuator.

[0056] For clockwise rotation about the pitch axis 536, actuator pull or torque transmission mechanisms 553 and 554, and simultaneously force or torque transmission mechanisms 551 and 552, are moved accordingly, facilitated, or allowed to follow the movement. Conversely, for counterclockwise rotation about the pitch axis 536, actuator pull or torque transmission mechanisms 551 and 552, and simultaneously force or torque transmission mechanisms 553 and 554, are moved accordingly, facilitated, or allowed to follow the movement.

[0057] To rotate the gripper 522 clockwise around axis 528, the actuator pulling force or torque transmission mechanism 552 and simultaneously the force or torque transmission mechanism 551 are moved accordingly, facilitated, or allowed to follow the movement. Conversely, to rotate the gripper 522 counterclockwise around axis 528, the actuator pulling force or torque transmission mechanism 551 and simultaneously the force or torque transmission mechanism 552 are moved, facilitated, or allowed to follow the movement.

[0058] Rotation of gripper 524 about axis 528 is achieved using force or torque transmission mechanisms 553 and 554. To rotate gripper 524 clockwise about axis 528, actuator pulls force or torque transmission mechanism 554, and simultaneously force or torque transmission mechanism 553 is moved, facilitated, or allowed to follow the movement. Conversely, to rotate gripper 524 counterclockwise about axis 528, actuator pulls force or torque transmission mechanism 553, and simultaneously force or torque transmission mechanism 554 is moved, facilitated, or allowed to follow the movement.

[0059] As described above and similar Figure 4 In one embodiment, the coordinated movement of grippers 522, 524 toward each other, away from each other, and in the same direction provides gripper gripping-releasing and yaw DOF.

[0060] Table I summarizes the various force or torque transmission mechanism manipulations used to control the pitch, yaw, and clamp-and-release DOF of the device 500. The term "follow" in Table I is used to indicate "being moved, being facilitated to move, or being allowed to follow movement." In some embodiments, combinations of pitch, yaw, and clamp-and-release can be obtained by overlapping (e.g., by linear superposition) various pull and move, facilitate movement, or allow movement to follow actuation levels, thereby achieving the desired mixed motion of the DOF of the device 500. Thus, to a certain extent, each actuator operates with at least some antagonism relative to each other.

[0061] Table I

[0062]

[0063] According to some embodiments, other configurations involve more actuators or DOFs than described above. In each system with more actuators than DOFs, there exists a continuum for selecting actuator force combinations. Control of each DOF involves coordinated control of actuators coupled to various force or torque transmission mechanisms.

[0064] For example, jointly owned international patent application number PCT / US2018 / 050151 (which is incorporated herein by reference) describes several methods for selecting actuator force combinations, such as selecting a combination with the minimum magnitude but still subject to the minimum tension constraints in the force or torque transmission mechanism. This method is designed to reduce wear on the force or torque transmission mechanism. However, this method does not take into account the inertia within the actuator and / or the force or torque mechanism. As a result, this method may cause the actuator to move asynchronously with the desired DOF motion, causing one actuator to act on the inertia of another actuator through a compliant drive mechanism and / or similar mechanism. In some cases, this may lead to undesirable oscillations in the system and / or in one or more DOFs.

[0065] According to some embodiments, in order to achieve a counter-control method with less unwanted oscillation, mitigate external disturbance forces and / or torques, and / or resolve inertia within the actuator and / or force or torque mechanism, the actuation level of the actuator can be coordinated to maintain tension in each force or torque transmission mechanism at least zero (0), while avoiding applying tension beyond what is necessary to prevent oscillations.

[0066] Figure 6 This is a simplified diagram of a control system 600 for a device's DOF ​​according to some embodiments. In some embodiments, the device can be... Figure 2 - Figure 5B Consistent with any instrument. For example... Figure 6As shown, the control system 600 includes a DOF control module 610 and an actuation control module 620. According to some embodiments, the control system 600 is configured to use two actuators to control a single DOF, for example, with... Figure 3 The control of the fingers 322 and actuators 341 and 342 described in the embodiments is consistent.

[0067] As shown in the figure, the control system 600 is configured to receive the desired DOF state (x avdes The minimum tension (ε) and the minimum tension (ε) are used to generate actuation levels F1 and F2 for the corresponding first and second actuators. In some examples, the desired DOF state x avdes This corresponds to the desired linear position, desired rotational position, desired linear velocity, desired rotational velocity, etc., of the DOF. In some examples, the desired DOF state x can be received from another control module (not shown). avdes For example, it can be used to follow a desired exercise plan, a desired trajectory, etc. In some examples, the desired DOF state x avdes The minimum tension ε can be determined based on input received from one or more input controls manipulated by the operator. In some examples, the minimum tension ε may correspond to the minimum tension maintained in one or more force or torque transmission mechanisms that connect the DOF to the first and second actuators. In some examples, the minimum tension ε may be set based on one or more of the following: operator preference, instrument calibration, type of instrument and / or the DOF being controlled, type of procedure being performed, type of material manipulated using the DOF, etc. In some examples, the target minimum tension ε may be in the range of 3 Newtons to 8 Newtons. In some examples, each of the actuation levels F1 and / or F2 may correspond to the force or torque to be applied by the respective actuator to control the DOF.

[0068] The control system 600 further receives information about the current position x1 of the first actuator and the current position x2 of the second actuator. In some examples, each of positions x1 and x2 may correspond to the rotational position and / or linear position of the respective actuator. In some examples, each of positions x1 and x2 may correspond to the distance by which the respective force or torque transmission mechanism is pulled and / or follows the respective actuator. In some examples, each of positions x1 and x2 may be determined from readings of one or more sensors (e.g., one or more position sensors, position encoders, etc.). In some examples, each of positions x1 and x2 may be determined using one or more kinematic models. In some examples, each of positions x1 and x2 may be determined based on one or more images of the respective actuator and / or the respective force or torque transmission mechanism.

[0069] DOF control module 610 receives the position x1 of the first actuator, the position x2 of the second actuator, and the desired DOF state x. avdes And determine the overall actuation command (F) used to control the DOF. cmd In some examples, the actuation command F cmd Based on the expected DOF state x avdes The position x1 and x2 of the first and second actuators are determined by the error. In some examples, the DOF control module 610 may include one or more dynamic and / or kinematic models for determining the position x1 and x2 and the desired DOF state x based on the first and / or second actuators, one or more force or torque transmission mechanisms, the DOF and / or other components of the device. avdes Mapped to actuation command F cmd The transfer function.

[0070] The actuation control module 620 receives positions x1 and x2 and force command F. cmd The actuation control module 620 generates actuation levels F1 and F2 for the first and second actuators, respectively, and a target minimum tension ε. In some examples, the actuation control module 620 compensates for any disturbance forces and / or torques applied to the DOF. In some examples, the actuation control module 620 compensates for the dynamics of the first and / or second actuators, one or more force or torque transmission mechanisms, the DOF, and / or other components of the device. In some examples, the dynamics may include one or more of inertia and / or tension and / or compression in the first and / or second actuators, one or more force transmission mechanisms, and / or other components of the device. In some examples, the disturbance forces and / or torques applied to the DOF are explained using actuation levels F1 or F2 that are capable of resisting (e.g., pulling against) the disturbance forces and / or torques. In some examples, the dynamics of the first and / or second actuators, one or more force or torque transmission mechanisms, the DOF, and / or other components of the device are explained using actuation levels F1 and F2. In some examples, actuation levels F1 and F2 accelerate one or more force or torque transmission mechanisms, the DOF, and / or other components of the device. In some examples, because the disturbance forces and / or torques are estimated, an accurate decomposition between the actuation levels F1 or F2 used to address the disturbance forces and / or torques is estimated, and the total actuation levels F1 and F2 take into account both the disturbance forces and / or torques of one or more force or torque transmission mechanisms, DOFs and / or other components of the apparatus, as well as the dynamics.

[0071] In some examples, the actuation control module 620 can be used to control the DOF in an instrument, wherein one or more force or torque transmission mechanisms of the instrument are stored without tension (e.g., because tension in one or more force or torque transmission mechanisms is released when the instrument is not coupled to the actuation control module 620), because the actuation control module 620 is capable of dynamically adjusting the tension in one or more force or torque transmission mechanisms before use and in response to changes in the dynamics of the first and / or second actuators, one or more force or torque transmission mechanisms, the DOF, and / or other components of the instrument.

[0072] According to some embodiments, the derivation of the DOF control module 610 and / or actuation control module 620 depends on the controlled device, the DOF of the controlled device, and / or the extent to which the DOF can cooperate with at least one other DOF. As a non-limiting example, Figure 7 A simplified diagram of a free-body figure 700 for a device according to some embodiments is shown. Figure 7 As shown, DOF is simulated as having the current position x DOF A linear DOF. This DOF ​​is connected to a first linear actuator via a first force transmission mechanism along a first direction (e.g., towards). Figure 7 The first linear actuator (left side) is controlled by a first linear actuator having a mass m, a position x1, and applying an actuating force F1 to pull and / or release a first force transmission mechanism. The first force transmission mechanism is simulated as a spring, where the spring constant is k. The DOF is controlled by a second linear actuator connected to the DOF via a second force transmission mechanism along a second direction (e.g., towards). Figure 7 (Right side of the diagram) Control. The second linear actuator has mass m, position x2, and applies an actuating force F2 to pull and / or release the second force transmission mechanism. The second force transmission mechanism is simulated in a spring-like manner, where the spring constant is k. Free body Figure 700 further shows the DOF subjected to an externally applied disturbance force F. d In some examples, the mass m and / or spring constant k can be determined empirically. In other examples, the mass m and / or spring constant k can be determined individually for each linear actuator and related component, for example, by using a calibration procedure.

[0073] Assuming that the first and second force transmission mechanisms are of the same length and that there is no tension or compression in either of the first or second force transmission mechanisms, position x DOF Corresponding to the midpoint between x1 and x2, such that x DOF＝ x av = (x1 + x2) / 2. In practice, the lengths of the first and second force transmission mechanisms may not be the same. For example, the combined length x of the first and second force transmission mechanisms may be different. Δ=x2 – x1 combined with the combined static length of the first and second force transmission mechanisms x ΔR There may be differences between (e.g., without stretching or compression).

[0074] In order to control Figure 7 The DOF aims to correspond as closely as possible to the x-state of the nominal desired DOF. av Force command F (e.g., nominal desired position) cmd With tension F T Decoupling, the tension F T Considering the tension in the first and second force transmission mechanisms and contributing to reducing the possibility of deformation of the first and second force transmission mechanisms and / or oscillations in the system. In some examples, F T It is set to the minimum tension ε. In some examples, F T It may include an optional damping factor according to Equation 1, where k d It is the damping constant and It is x Δ The first derivative of F. In some examples, F T It can remain between the lower and upper limits. However, in practice, this decoupling is not entirely possible because the force command F... cmd In addition to moving the DOF to the desired DOF location x av In addition, it may also be necessary to overcome the disturbance force F d But the disturbance force F d It may change with the state of DOF and may also affect the tension and deformation in the first and second force transmission mechanisms.

[0075]

[0076] Solving the system dynamics of the free body diagram 700 yields equations 2 and 3.

[0077]

[0078]

[0079] Let F cmd =F2–F1 and provides tension control so that F2+F1=2F T +F d Solving F1 and F2 will yield equations 4 and 5, respectively.

[0080]

[0081]

[0082] Therefore, if F d F cmd and FT Since it is known, the actuating forces F1 and F2 applied by the first and second actuators respectively can be determined to compensate for the external disturbance force F. d Expected DOF state x avdes And the minimum tension ε of the first and second force transmission mechanisms, while also taking into account any inertia of the first and / or second actuators and / or the first and second force transmission mechanisms, and / or any tension and / or compression of the first and / or second force transmission mechanisms. F cmd Dynamics can be controlled based on the position of the DOF (e.g., based on x1, x2, and the desired DOF state x). avdes ) to determine, F T It is determined based on the minimum tension ε and the selectable damping factor, but in general, F d It is external and is usually unknowable and / or cannot be directly measured.

[0083] According to some embodiments, there exists a method for estimating the disturbance force F. d To obtain the estimated disturbance force At least two options are available. In some examples, the estimated perturbation force... It can be determined based on the system dynamics according to Equation 6. In some examples, the estimated disturbance force... Alternative uses such as Figure 8 The disturbance observer shown is used to determine this.

[0084]

[0085] Figure 8 According to some embodiments, it is used for Figure 7 A simplified diagram of the DOF control system 800. In some embodiments, control system 800 is consistent with control system 600. Figure 8 As shown, the desired DOF state x avdes and x av The error between x1 and x2 (e.g., position error) is transmitted through a DOF control module (e.g., similar to DOF control module 610, where x is inferred from x1 and x2). av ) Generate force command F cmd =F2–F1. Based on the dynamics of the machine, through inertial dynamics (1 / (2ms) 2 Adjustment force command F cmd With disturbance force F d Difference control between x av The actual DOF state x is further adjusted by tension dynamics via the first and second force transmission mechanisms (2k) based on the dynamics of the instrument. DOF With x av The difference between them leads to the disturbance force F dFurthermore, the actual DOF position x is obtained based on the dynamics of the external device. DOF .

[0086] Then, the disturbance observer 810 is used to determine the estimated disturbance force. The disturbance observer 810 uses the inverse dynamic model passed through the actuator (2ms) 2 The force command F cmd With x av The difference between them determines the estimated disturbance force. The disturbance observer 810 is also shown with an optional low-pass filter Q that limits the effects of high-frequency disturbances to determine the estimated disturbance force. The ability to reduce high-frequency jitter during DOF control. In some examples, the low-pass filter Q can also reduce high-frequency jitter during DOF control.

[0087] Then, a feedback loop can be used to determine F2+F1 as the estimated disturbance force. With 2F T The sum of the absolute values ​​(abs), where the combined length x of the first and second force transmission mechanisms is determined by the tension control module. Δ Combined static length x ΔR The difference between them determines F T The tension control module takes into account the desired target tension ε and the optional damping term in Equation 1. The combined length x of the first and second force transmission mechanisms. Δ Combined static length x ΔR The difference between them is based on taking into account inertia and tension dynamics (1 / (ms) 2 F2+F1 after +k))

[0088] Force command F cmd =F2–F1 and based on the estimated disturbance force and F T The determined F2+F1 can then be used to determine F1 and F2, which are the actuation levels of the first and second actuators, respectively. Advantageously, the method takes into account the inertia in the first and second actuators and the first and second force transmission mechanisms, as well as any tension and / or compression in the first or second force transmission mechanism. Furthermore, the method allows for control of the tension in the first and / or second force transmission mechanisms during use, making it possible to release the tension in the first and second force transmission mechanisms when the device is not coupled to a medical device and to store the device without keeping the first and / or second force transmission mechanisms taut. In some examples, one or more of these advantages can reduce device costs because a wider range of materials can be used in the first and second force transmission mechanisms, and / or increase device life because the tension in the first and / or second force transmission mechanisms can generally be reduced overall.

[0089] And despite Figure 7 and Figure 8 The derivation of the control system has been greatly simplified, but it should be understood that... Figure 7 and Figure 8 The embodiments described can be adapted to other configurations and arrangements. In some embodiments, the motion chains for controlling the DOF in the two directions do not need to be symmetrical. In some examples, the mass of the first actuator may be different from the mass of the second actuator. In some examples, the spring constant of the first force transmission mechanism may be different from the spring constant of the second force transmission mechanism. In some examples, the lengths of the first and second force transmission mechanisms may be different, such that x can be replaced by different functions of x1 and x2. av This is consistent with the lengths of the first and second force transmission mechanisms. In some examples, the minimum tension of the first and second force transmission mechanisms may be different. In some embodiments, the positions (x1, x2 and / or x...) DOF Any of the following can be a linear position and / or a rotational position and / or any combination thereof. In some embodiments, one or more forces (F1, F2, and / or F...) d The force can be a force or torque and / or any combination thereof. In some embodiments, mass and the corresponding inertia can be modeled as linear and / or rotational mass and / or inertia. In some embodiments, the first and / or second force transmission mechanism can alternatively be based on a nonlinear model. In some embodiments, the first and / or second linear actuator can include a solenoid, an actuator-driven lead screw, and / or the like. In some embodiments, the first and / or second linear actuator can be replaced with and / or include a rotary actuator (e.g., a motor, servo, and / or the like). In some embodiments, the first and / or second force transmission mechanism can include one or more cables, belts, chains, pulleys, sprockets, gears, and / or the like.

[0090] And despite Figure 7 and Figure 8 The diagram illustrates the dynamics and generated control system for a linear version of the finger 322 of the instrument 300; however, in other embodiments, the free-body diagram 700 and the control system 800 can be adapted to other instruments and DOF arrangements. In some examples, Figure 7 The linear positions x1 and x2 can be replaced by the rotational positions of actuators 341 and / or 342. In some examples, the external disturbance force F dExternal disturbance torque can be used instead. In some examples, the actuation of actuators 341 and / or 342 can be simulated using force and / or torque depending on their configuration. In some examples, the device 400 can be controlled using a separate control system similar to the control system 800 for each gripper 422 and 424. In some examples, the interaction that may occur between grippers 422 and 424 during clamping and releasing can be accounted for using a corresponding estimated disturbance force or torque, which includes any external disturbance force or torque caused by the mutual pushing of grippers 422 and 424 and / or the mutual pushing of grippers 422 and 424 through the clamped material.

[0091] In some embodiments, the free body diagram 700 and the control system 800 can be similarly applied. Figure 5A and Figure 5B The three-DOF four-actuator device 500, although more complex in its arrangement among the DOFs and the influence of external disturbances or torques on any one of the three DOFs, will also generate external disturbances or torques on the other DOFs. In some examples, the free-body diagram of device 500 may include four disturbance observers, each used for each of the actuators and corresponding force or torque transmission mechanisms 551-554. In some examples, the absolute value block applied to each estimated disturbance force can be replaced by a block implementing Equation 7, where C null It is the null space row of the coupling matrix that converts actuator positions into joint positions and / or states, where minel is the smallest element. Will The vector is projected onto the null-perp space, thus eliminating the projection of the perturbation force onto the torque null space. In some examples, the system dynamics (e.g., 2ms) 2 1 / (2ms) 2 ) and 1 / (ms 2 +k)) is replaced with the corresponding dynamic model of the three-DOF four-actuator instrument system.

[0092] F null Make

[0093] Figure 9This is a simplified diagram of a method 900 for controlling a DOF of an apparatus according to some embodiments. One or more of the processes 910-970 of method 900 may be implemented at least partially in the form of executable code stored on a non-transitory tangible machine-readable medium, which, when run by one or more processors (e.g., processor 150 in control unit 140), enables one or more processors to implement one or more of processes 910-970. In some embodiments, method 900 may be performed by a module such as control module 170. In some embodiments, method 900 may be used to operate the apparatus such that control of the DOF takes into account the inertia in the actuators, force or torque transmission mechanisms, and / or other components of the apparatus used to control the DOF, and takes into account tension and / or compression in the force or torque transmission mechanisms. In some examples, method 900 may be used to execute a program using any of apparatuses 200, 300, 400, and / or 500. In some examples, method 900 may be implemented at least partially by a control system such as control system 600 and / or control system 800.

[0094] At process 910, a minimum tension is determined. In some examples, this minimum tension may correspond to a minimum tension ε. In some examples, this minimum tension may correspond to the minimum tension to be maintained in one or more force or torque transmission mechanisms that connect the DOF to one or more corresponding actuators. In some examples, different minimum tensions may be determined for different force or torque transmission mechanisms. In some examples, this minimum tension may be set based on one or more of the following: operator preference, instrument calibration, type of instrument and / or the DOF being controlled, type of procedure being performed, type of material being manipulated using the DOF (e.g., tissue in a medical example), etc. In some examples, this minimum tension may be in the range of 3 to 8 Newtons.

[0095] At step 920, the desired DOF state is determined. In some examples, the desired DOF state may correspond to the desired DOF state x. avdes In some examples, the desired DOF state corresponds to the desired linear position, desired rotational position, desired linear velocity, desired rotational velocity, etc., of the DOF. In some examples, the desired DOF state can be received from a control module, for example, it can be used to follow a desired motion plan, desired trajectory, etc. In some examples, the desired DOF state x can be determined based on input received from one or more input controls manipulated by the operator. avdes .

[0096] At process 930, a first position of the first actuator is determined. In some examples, the first position may correspond to position x1. In some examples, the first actuator may correspond to actuators 341 and / or 342. In some examples, the first position may correspond to a rotational position and / or a linear position of the first actuator. In some examples, the first position may correspond to a distance by which the first force or torque transmission mechanism is pulled and / or follows the first actuator. In some examples, the first position may be determined based on readings from one or more sensors (e.g., one or more position sensors, position encoders, etc.). In some examples, the first position may be determined using one or more kinematic models. In some examples, the first position may be determined based on one or more images of the first actuator and / or the first force or torque transmission mechanism.

[0097] At process 940, a second position of the second actuator is determined. In some examples, the second position may coincide with position x2. In some examples, the second actuator may coincide with actuators 341 and / or 342. In some examples, process 940 may be substantially similar to process 930.

[0098] At process 950, an actuation command for the DOF is determined. In some examples, this actuation command may be a force or torque command to drive the DOF to the desired DOF state determined during process 920. In some examples, the actuation command for the DOF may correspond to the difference between the actuation level applied by the second actuator and the actuation level applied by the first actuator. In some examples, the actuation command for the DOF may be related to F... cmd Consistent. In some examples, commands for DOF can use, such as DOF ​​control module 610 and / or Figure 8 The DOF control module, such as a DOF control module, determines the DOF state. In some examples, the actuation command for the DOF can be determined based on one or more of a first position, a second position, a desired DOF state, and the actual DOF state. In some examples, the actual DOF state can be determined using one or more sensors, one or more images of the DOF, etc. In some examples, the actual DOF state can be indirectly determined based on the first and second positions. In some examples, the actual DOF state can be determined based on the dynamics of one or more of a first actuator, a second actuator, a first force or torque transmission mechanism, and / or a second force or torque transmission mechanism.

[0099] At process 960, a first actuation level for the first actuator and a second actuation level for the second actuator are determined. In some examples, the first actuation level may be a first actuating force or a first actuating torque, and / or the second actuation level may be a second actuating force or a second actuating torque. In some examples, the first and second actuation levels may correspond to actuating forces F1 and F2, respectively. In some examples, the first and second actuation levels may be determined using an actuation control module such as actuation control module 620 and / or control system 800. In some examples, the first and second actuation levels may be determined based on the dynamics of the device, DOF, and / or the first and second actuators. In some examples, the dynamics include one or more of the inertia of the first actuator and / or the first force or torque transmission mechanism, the inertia of the second actuator and / or the second force or torque transmission mechanism, tension and / or compression in the first force or torque transmission mechanism, and / or tension and / or compression in the second force or torque transmission mechanism.

[0100] In some examples, the first and second actuation levels can be determined based on one or more of the following: an actuation command for the DOF determined during process 950, a minimum tension determined during process 910, a first position determined during process 940, and / or a second position determined during process 950. In some examples, the first and second actuation levels can be determined based on the actuation command, an estimate of the external disturbance force or torque applied to the DOF, and the tension force or torque. In some examples, the tension force or torque can be related to the tension force F. T Consistent. In some examples, the tension force or torque may be based on the minimum tension determined during process 910. In some examples, the tension force or torque may include a damping term. In some examples, the tension force or torque may be determined using Equation 1. In some examples, the tension force or torque may be maintained between a lower limit and an upper limit. In some examples, the estimate of the external disturbance force or torque may be consistent with the estimated disturbance force. Consistent. In some examples, the estimate of the external disturbance force or torque can be determined based on the dynamics of the instrument, DOF, and / or the first and second actuators, for example, by using Equation 6. In some examples, the estimate of the external disturbance force or torque can be determined using a disturbance observer (e.g., disturbance observer 810). In some examples, the disturbance observer may include one or more low-pass filters to remove high-frequency components from the estimate of the external disturbance force or torque.

[0101] At process 970, first and second actuators are used to control the DOF. A first actuation level is used to determine the force or torque applied by the first actuator, while a second actuation level is used to determine the force or torque applied by the second actuator. In some examples, the first and second actuation levels can be provided as setpoints to corresponding controllers configured to control the first and second actuators, respectively.

[0102] In some embodiments, method 900 may be repeated multiple times by returning to process 910 when a different minimum tension is required, returning to process 920 when the desired DOF state changes, and / or returning to process 930 as part of the next control cycle. In some examples, method 900 may be repeated in each control cycle of the instrument and / or DOF.

[0103] Advantageously, method 900 takes into account the inertia in the first and second actuators and the first and second force or torque transmission mechanisms, as well as any tension and / or compression in the first or second force or torque transmission mechanisms. Furthermore, method 900 allows for control of the tension in the first and / or second force or torque transmission mechanisms during use, thereby making it possible to store the device without having to maintain tension in the first and / or second force or torque transmission mechanisms (e.g., releasing the tension in the first and / or second force or torque transmission mechanisms after use). In some examples, one or more of these advantages can reduce device costs because a wider range of materials can be used in the first and second force or torque transmission mechanisms, and / or increase device life because the tension in the first and / or second force or torque transmission mechanisms can generally be reduced overall.

[0104] Examples of control units, such as control unit 140, may include non-transitory tangible machine-readable media comprising machine-readable instructions that, when executed by one or more processors (e.g., processor 150), cause one or more processors to perform calculations of the process and / or control system 600 and / or 800 of method 900. Some common forms of machine-readable media that may include calculations of the process and / or control system 600 and / or 800 of method 900 are, for example, floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, any other optical media, punched cards, paper tape, any other physical media with a perforated pattern, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cassette memory, and / or any other media suitable for reading by a processor or computer.

[0105] Although illustrative embodiments have been shown and described, extensive modifications, alterations, and substitutions are contemplated in the foregoing disclosure, and in some cases, some features of the embodiments may be employed without correspondingly using other features. Many variations, substitutions, and modifications will be recognized by those skilled in the art. Therefore, the scope of the invention should be limited only by the following claims, and it is appropriate to interpret the claims broadly in a manner consistent with the scope of the embodiments disclosed herein.

Claims

1. A computer-assisted device, comprising: a first actuator configured to actuate a degree of freedom of an instrument in a first direction using a first force or torque transmission mechanism; a second actuator configured to actuate the degree of freedom in a second direction using a second force or torque transmission mechanism, the second direction being at least partially opposite to the first direction; and a control unit coupled to the first actuator and the second actuator; wherein the control unit is configured to: determine a first position of the first actuator; determine a second position of the second actuator; determine a force or torque command based on the first position, the second position, and a desired state of the degree of freedom; determine a first actuation level of the first actuator and a second actuation level of the second actuator so as to maintain a first tension in the first force or torque transmission mechanism above a first minimum tension and to maintain a second tension in the second force or torque transmission mechanism above a second minimum tension by utilizing a model based on the force or torque command, the first minimum tension and the second minimum tension, the first position, and the second position; and command actuation of the first actuator at the first actuation level and actuation of the second actuator at the second actuation level; wherein the model compensates for external disturbances on the degree of freedom, dynamics of the first actuator and the second actuator, and inertia of the first force or torque transmission mechanism and the second force or torque transmission mechanism.

2. The computer-assisted device of claim 1, wherein the computer-assisted device is a medical device, and wherein the instrument is a medical instrument.

3. The computer-assisted device of claim 1, wherein the instrument includes a second degree of freedom configured to operate independently of the degree of freedom.

4. The computer-assisted device of claim 1, wherein the instrument includes a second degree of freedom configured to operate in coordination with the degree of freedom.

5. The computer-assisted device of claim 1, wherein the instrument includes three degrees of freedom configured to be controlled by four actuators.

6. The computer-assisted device of claim 5, wherein the three degrees of freedom include pitch, yaw, and grip.

7. The computer-assisted device of claim 1, wherein the desired state of the degree of freedom is a linear position.

8. The computer-assisted device of claim 1, wherein the desired state of the degree of freedom is a rotational position.

9. The computer-assisted device of claim 1, wherein the desired state of the degree of freedom is a velocity.

10. The computer-assisted device of claim 1, wherein the model compensates for the dynamics of the first actuator by modeling inertia of the first actuator.

11. The computer-assisted device of claim 1, wherein the model further compensates for dynamics of the first force or torque transmission mechanism by modeling tension or compression in the first force or torque transmission mechanism. ​ ​ 12. The computer-assisted device of any one of claims 1-11, wherein the force or torque command is a difference between the second actuation level and the first actuation level.

13. The computer-assisted device of any one of claims 1-11, wherein the control unit is further configured to determine a position of the degree of freedom based on the first position, the second position, a length of the first force or torque transmission mechanism, and a length of the second force or torque transmission mechanism.

14. The computer-assisted device of any one of claims 1-11, wherein the control unit is further configured to estimate the external disturbance on the degree of freedom based on the dynamics.

15. The computer-assisted device of any one of claims 1-11, wherein the control unit is further configured to estimate the external disturbance on the degree of freedom using a disturbance observer.

16. The computer-assisted device of claim 15, wherein the disturbance observer includes one or more low-pass filters to remove high frequency components from the estimated external disturbance.

17. The computer-assisted device of any one of claims 1-11, wherein the control unit is further configured to determine at least one of the first minimum tension or the second minimum tension based on one or more of a calibration of the instrument, a type of the instrument, or a type of a procedure being performed.

18. The computer-assisted device of any one of claims 1-11, wherein the control unit is further configured to pre-tension the first force or torque transmission mechanism and the second force or torque transmission mechanism based on the first minimum tension and the second minimum tension prior to use of the instrument.

19. The computer-assisted device of any one of claims 1-11, wherein tension in the first force or torque transmission mechanism and the second force or torque transmission mechanism is released when the instrument is not coupled to the computer-assisted device.

20. The computer-assisted device of any one of claims 1-11, wherein the model further adjusts the first tension or the second tension based on a damping factor.

21. The computer-assisted device of any one of claims 1-11, wherein the control unit is further configured to maintain the first tension and the second tension between a lower limit and an upper limit.

22. A method comprising: determining, by a control unit of a computer-assisted device, a first position of a first actuator configured to actuate a degree of freedom of an instrument in a first direction using a first force or torque transmission mechanism; determining, by the control unit, a second position of a second actuator configured to actuate the degree of freedom in a second direction using a second force or torque transmission mechanism, the second direction being at least partially opposite the first direction; determining, by the control unit, a force or torque command based on the first position, the second position, and a desired state of the degree of freedom; determining, by the control unit, a first actuation level of the first actuator and a second actuation level of the second actuator so as to maintain a first tension in the first force or torque transmission mechanism above a first minimum tension and to maintain a second tension in the second force or torque transmission mechanism above a second minimum tension by utilizing a model based on the force or torque command, the first minimum tension and the second minimum tension, the first position and the second position; and commanding, by the control unit, actuation of the first actuator at the first actuation level and actuation of the second actuator at the second actuation level; wherein the model compensates for external disturbances on the degree of freedom, dynamics of the first actuator and the second actuator, and inertia of the first force or torque transmission mechanism and the second force or torque transmission mechanism.

23. The method of claim 22, wherein the computer-assisted device is a medical device, and wherein the instrument is a medical instrument.

24. The method of claim 22, wherein the instrument includes a second degree of freedom configured to operate independently of the degree of freedom.

25. The method of claim 22, wherein the instrument includes a second degree of freedom configured to operate in coordination with the degree of freedom.

26. The method of claim 22, wherein the instrument includes three degrees of freedom configured to be controlled by four actuators.

27. The method of claim 26, wherein the three degrees of freedom include pitch, yaw, and grip.

28. The method of claim 22, wherein the desired state of the degree of freedom is a linear position.

29. The method of claim 22, wherein the desired state of the degree of freedom is a rotational position.

30. The method of claim 22, wherein the desired state of the degree of freedom is a velocity.

31. The method of claim 22, further comprising: compensating for the dynamics of the first actuator using the model by simulating inertia of the first actuator.

32. The method of claim 22, further comprising: compensating for dynamics of the first force or torque transmission mechanism using the model by simulating tension or compression in the first force or torque transmission mechanism.

33. The method of any of claims 22-32, wherein the force or torque command is a difference between the second actuation level and the first actuation level.

34. The method of any one of claims 22-32, further comprising: determining a position of the degree of freedom based on the first position, the second position, a length of the first force or torque transmission mechanism, and a length of the second force or torque transmission mechanism.

35. The method of any one of claims 22-32, further comprising: estimating the external disturbances on the degree of freedom based on the dynamics.

36. The method of any one of claims 22-32, further comprising: estimating the external disturbances on the degree of freedom using a disturbance observer.

37. The method of claim 36, wherein the disturbance observer includes one or more low-pass filters to remove high frequency components from the estimated external disturbances.

38. The method of any one of claims 22-32, further comprising: determining at least one of the first minimum tension or the second minimum tension based on one or more of a calibration of the instrument, a type of the instrument, or a type of a procedure being performed.

39. The method of any one of claims 22-32, further comprising: pre-tensioning the first and second force or torque transmission mechanisms prior to use of the instrument based on the first and second minimum tensions.

40. The method of any of claims 22-32, wherein tension in the first and second force or torque transmission mechanisms is released when the instrument is not coupled to the computer-assisted device.

41. The method of any one of claims 22-32, further comprising: adjusting the first or second tension based on a damping factor.

42. The method of any one of claims 22-32, further comprising: maintaining the first and second tensions between a lower limit and an upper limit.

43. A non-transitory machine-readable medium comprising a plurality of machine- readable instructions that, when executed by one or more processors associated with a computer-assisted medical device, are adapted to cause the one or more processors to implement a method comprising: determining a first position of a first actuator configured to actuate a degree of freedom of an instrument in a first direction using a first force or torque transmission mechanism; determining a second position of a second actuator configured to actuate the degree of freedom in a second direction using a second force or torque transmission mechanism, the second direction being at least partially opposite the first direction; determining a force or torque command based on the first position, the second position, and a desired state of the degree of freedom; determining a first actuation level of the first actuator and a second actuation level of the second actuator so as to maintain a first tension in the first force or torque transmission mechanism above a first minimum tension and a second tension in the second force or torque transmission mechanism above a second minimum tension by utilizing a model based on the force or torque command, the first and second minimum tensions, the first and second positions; and commanding actuation of the first actuator at the first actuation level and actuation of the second actuator at the second actuation level; wherein the model compensates for external disturbances on the degree of freedom, dynamics of the first and second actuators, and inertia of the first and second force or torque transmission mechanisms.

44. The non-transitory machine-readable medium of claim 43, wherein the instrument is a medical instrument.

45. The non-transitory machine-readable medium of claim 43, wherein the instrument comprises a second degree of freedom configured to operate independently of the degree of freedom.

46. The non-transitory machine-readable medium of claim 43, wherein the instrument comprises a second degree of freedom configured to operate in coordination with the degree of freedom.

47. The non-transitory machine-readable medium of claim 43, wherein the instrument comprises three degrees of freedom configured to be controlled by four actuators.

48. The non-transitory machine-readable medium of claim 47, wherein the three degrees of freedom comprise pitch, yaw, and grip.

49. The non-transitory machine-readable medium of claim 43, wherein the desired state of the degree of freedom is a linear position.

50. The non-transitory machine readable medium of claim 43, wherein the desired state of the degree of freedom is a rotational position.

51. The non-transitory machine readable medium of claim 43, wherein the desired state of the degree of freedom is a velocity.

52. The non-transitory machine-readable medium of claim 43, wherein the method further comprises: compensate for the dynamics of the first actuator using the model by simulating inertia of the first actuator.

53. The non-transitory machine-readable medium of claim 43, wherein the method further comprises: compensate for the dynamics of the first force or torque transmission mechanism using the model by simulating tension or compression in the first force or torque transmission mechanism.

54. The non-transitory machine readable medium of any of claims 43-53, wherein the force or torque command is a difference between the second actuation level and the first actuation level.

55. The non-transitory machine-readable medium of any one of claims 43-53, wherein the method further comprises: determine a position of the degree of freedom based on the first position, the second position, a length of the first force or torque transmission mechanism, and a length of the second force or torque transmission mechanism.

56. The non-transitory machine-readable medium of any one of claims 43-53, wherein the method further comprises: estimate the external disturbance on the degree of freedom based on the dynamics.

57. The non-transitory machine-readable medium of any one of claims 43-53, wherein the method further comprises: estimate the external disturbance on the degree of freedom using a disturbance observer.

58. The non-transitory machine readable medium of claim 57, wherein the disturbance observer includes one or more low pass filters to remove high frequency components from the estimated external disturbance.

59. The non-transitory machine-readable medium of any one of claims 43-53, wherein the method further comprises: determine at least one of the first minimum tension or the second minimum tension based on one or more of a calibration of the instrument, a type of the instrument, or a type of procedure being performed.

60. The non-transitory machine-readable medium of any one of claims 43-53, wherein the method further comprises: pre-tension the first force or torque transmission mechanism and the second force or torque transmission mechanism based on the first minimum tension and the second minimum tension prior to use of the instrument.

61. The non-transitory machine readable medium of any of claims 43-53, wherein tension in the first force or torque transmission mechanism and the second force or torque transmission mechanism is released when the instrument is not coupled to the computer-assisted medical device.

62. The non-transitory machine-readable medium of any one of claims 43-53, wherein the method further comprises: adjust the first tension or the second tension based on a damping factor.

63. The non-transitory machine-readable medium of any one of claims 43-53, wherein the method further comprises: maintain the first tension and the second tension between a lower limit and an upper limit.

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