Controlled resistance in retractable joints

Abstract

Computer-based system (100) comprising: a manipulator arm (150, 502) comprising a joint (J1, J2, J3, J4, J5, J6) and an actuator mechanism (790) configured to drive the joint (J1, J2, J3, J4, J5, J6); and a controller (710) comprising a computer processor, the controller (710) being communicatively coupled to the manipulator arm (150, 502) and configured with a first control mode and a second control mode, wherein the controller (710) in both the first control mode and the second control mode commands the actuator mechanism (790) to allow external articulation to reconfigure the manipulator arm (150, 502) by retracting the joint (J1, J2, J3, J4, J5, J6), wherein the first control mode differs from the second control mode at least in that the controller (710) is configured to, in the first control mode, command the actuator mechanism (790) to provide a first speed-dependent resistance in response to the joint (J1, J2, J3, J4, J5, J6) being retracted at a first retraction speed above a first speed threshold, the first speed-dependent resistance opposing retraction of the joint (J1, J2, J3, J4, J5, J6).wherein the controller (710) is configured to, in the second control mode, command the actuator mechanism (790) to provide a second speed-dependent resistance in response to the joint (J1, J2, J3, J4, J5, J6) being retracted at a second retraction speed above a second speed threshold, the second speed-dependent resistance opposing retraction of the joint (J1, J2, J3, J4, J5, J6). where the second speed-dependent resistance differs from the first speed-dependent resistance.

Description

[0001] The present invention generally provides improved robotic and / or medical (including surgical) devices, systems and methods.

[0002] A system of robotic devices can be used to perform a task at a workstation. For example, robotic systems can include robotic manipulator assemblies for manipulating instruments to perform the task. The robotic manipulator assembly can include two or more links connected by one or more joints. The joints can be active joints, which are actively moved and controlled by the system. The joints can also be passive joints, which are not actively moved and controlled by the system. The joints can be rotary joints, prismatic joints, or other joints such as ball joints. The configuration of the robotic manipulator assembly can be determined by the positions and orientations of the joints, the structure of the robotic manipulator assembly, and the coupling of the links.

[0003] Robotic systems include industrial and recreational robotic systems. Robotic systems also include medical robotic systems used in diagnostic procedures, non-surgical treatments, surgical treatments, etc. A specific example of robotic systems is minimally invasive telesurgical robotic systems, where a surgeon can operate on a patient from the bedside or from a remote location. Telesurgery generally refers to operations performed with surgical systems in which the surgeon uses some form of remote control, such as a servomechanism, to control the movements of the surgical instruments, rather than directly holding and moving the instruments by hand. A medical robotic system that can be used for telesurgery or other telemedicine procedures may include a remotely controllable robotic manipulator assembly.The operator can remotely control the movement of the remote-controlled robotic manipulator assembly. The operator can also manually move parts of the medical robot system into positions or orientations within its environment.

[0004] EP 3 402 433 B1, EP 2 884 993 B1, EP 2 263 595 B1, EP 2 135 637 B1, WO 2020 / 205 634 A1, WO 2020 / 028 356 A1 are known as prior art.

[0005] It is an object of the present invention to provide improved robotic and / or medical (including surgical) devices, systems and methods.

[0006] This object is achieved by a computer-aided system having the features of claim 1 and a non-volatile machine-readable medium having the features of claim 16. Further advantages and features of the invention emerge from the subclaims, the description and the drawings.

[0007] In one aspect, one or more embodiments relate to a computer-based system comprising: a manipulator arm having a joint, an actuator mechanism configured to drive the joint, and a controller having a computer processor. The controller is communicatively coupled to the manipulator arm and configured with a first control mode and a second control mode. In both the first and second control modes, the controller commands the actuator mechanism to allow external articulation to reconfigure the manipulator arm by retracting the joint.The first control mode differs from the second control mode at least in that the controller is configured to, in the first control mode, command the actuator mechanism to provide a first speed-dependent resistance in response to the joint being retracted at a first retraction speed above a first speed threshold. The first speed-dependent resistance opposes the retraction of the joint.

[0008] In one aspect, one or more embodiments relate to a method of operating a robot system comprising a manipulator arm and a controller. The manipulator arm includes a joint and an actuator mechanism configured to drive the joint. The controller is configured with a first control mode and a second control mode. The method includes: when the controller is in both the first control mode and the second control mode, commanding the actuator mechanism, by the controller, to allow external articulation to reconfigure the manipulator arm by retracting the joint; and when the controller is in the first control mode, commanding the actuator mechanism, by the controller, to provide a first velocity-dependent resistance in response to retracting the joint at a first retraction velocity above a first velocity threshold.The first speed-dependent resistance counteracts the retraction of the joint, and the first control mode differs from the second control mode at least in the first speed-dependent resistance.

[0009] Further aspects of the invention will become apparent from the following description and the appended claims. Fig. 1A shows a top view of a computer-based system in a scenario of a robotic procedure according to one or more embodiments. Fig. Figure 1B shows schematically various components of the computer-based system, such as that of Fig. 1A, according to one or more embodiments. Fig. Figure 2 shows a perspective view illustrating a user control system used to input commands for the robot procedure scenario of Fig. 1A may be used, according to one or more embodiments. Fig. Figure 3 shows a perspective view of an auxiliary system used in the robot procedure scenario of Fig. 1A may be used, according to one or more embodiments. Fig. 4A shows a perspective view of a robotic manipulation system according to one or more embodiments. Fig. 4B shows a perspective view of a robotic manipulation system according to one or more embodiments. Fig. 5 shows an example of a manipulator assembly according to one or more embodiments. Fig. 6 shows a perspective view of a tool according to one or more embodiments. Fig. 7A and Fig. 7B illustrate control architectures for controlling a computer-based system according to one or more embodiments. Fig. 8 shows a flow diagram describing a method for providing controlled resistance in retractable joints according to one or more embodiments. Fig. 9 shows a resistance versus speed graph according to one or more embodiments.

[0010] Specific embodiments of the disclosure will now be described in detail with reference to the accompanying figures. Like elements in the various figures are designated by like reference numerals for consistency.

[0011] In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail in order to avoid unnecessarily obscuring the description.

[0012] Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not intended to imply or create a particular order of the elements, nor is it intended to limit an element to being only a single element, unless explicitly stated, e.g., with terms such as "before," "after," "single," and other such terminology. Rather, the use of ordinal numbers serves to distinguish between the elements. For example, a first element is different from a second element, and the first element may comprise more than one element and may follow (or precede) the second element in the order of the elements.

[0013] Although some of the examples described herein relate to surgical procedures or tools, or medical procedures and medical tools, the disclosed techniques also apply to medical and non-medical procedures and to medical and non-medical tools. For example, the tools, systems, and methods described herein may be used for non-medical purposes, including industrial applications, general robotic applications, and the grasping or manipulation of non-tissue workpieces. Other example applications include cosmetic enhancements, the imaging of human or animal anatomy, the acquisition of data from human or animal anatomy, the setup and disassembly of the system, and the training of medical or non-medical personnel.Other examples of applications include procedures on tissue removed from human or animal anatomy (without reconstructing it into a human or animal anatomy) and performing procedures on human or animal cadavers. Furthermore, these techniques can also be used for medical treatment or diagnostic procedures that may or may not involve surgical aspects.

[0014] In general, embodiments of the disclosure may facilitate the use of the robot systems or improve workflow under various conditions. For example, retracting a joint of a robot system may be possible in several different control modes of the robot system. It may be beneficial for a user performing the retraction to receive haptic feedback that allows them to recognize the current control mode. In other words, it may be desirable for the haptic feedback provided during retraction to be different for different control modes. In one or more embodiments, the haptic feedback includes a controlled resistance that counteracts the retraction of the joint. The controlled resistance may be specific to the control mode.For example, the controlled resistance may be higher in a first control mode than in a second control mode, allowing the user to distinguish between the first and second control modes based entirely or partially on the tactile sensation imparted by the strength of the resistance. Furthermore, it may also be advantageous to provide controlled resistance to provide tactile feedback that allows the user to avoid undesirable operating conditions of the joint. For example, in one embodiment, the controlled resistance is provided at a speed that is below a speed at which the actuator mechanism would saturate due to the back electromotive force (back EMF) of the actuator of the actuator mechanism.In such a scenario, a user retracting the joint may perceive the controlled resistance as a signal indicating that faster retraction is possible but undesirable. A detailed description of controlled resistance in retractable joints, including possible implementations and applications, is provided below.

[0015] Referring to the drawings, in which like reference numbers represent like parts in the several views, Fig. 1A is a plan view of a computer-assisted system (100) (hereinafter system (100)) in a robotic procedure scenario. While in Fig. 1A, the computer-assisted system (100) is depicted as a minimally invasive surgical robot system, the following description also applies to computer-assisted systems in other scenarios, e.g., non-surgical or non-medical scenarios. In the example of Fig. 1A, a diagnostic or therapeutic procedure is performed on a patient (190) lying on an operating table (110). The system (100) may include a user control system (120) for use by a user (192) (e.g., a clinician such as a surgeon in a medical example) during the procedure. One or more assistants (194) may also participate in the procedure. The system (100) may further include a robotic manipulation system (130) (e.g., a patient-side robotic device in a medical example) and an auxiliary system (140). The robotic manipulation system (130) may have at least one manipulator arm (150), each of which may carry a removably coupled tool (160) (also called an instrument (160)). In the Fig. 1A, the tool (160) may penetrate the body of the patient (190) through a natural opening, such as the mouth or anus, or through an incision, such as an incision in a body wall, such as the abdominal wall, while the user (192) views the work area (e.g., a surgical site in the surgical scenario) through the user control system (120). An image of the work area may be obtained using a tool (160) that includes an imaging device (e.g., an endoscope, an optical camera, an ultrasound probe, etc.) that can be used to image the work area and that can be manipulated by the robotic manipulation system (130) to position and orient the imaging device.The auxiliary system (140) can be used to process the images of the workspace for display to the user (192) via the user control system (120) or other display systems located local or remote from the procedure. The number of tools (160) used simultaneously generally depends on, among other things, the task and space constraints. When it is appropriate to change, clean, inspect, or reload one or more of the tools (160) used during a procedure, an assistant (194) can remove the tool (160) from the manipulator arm (150) and replace it with the same tool (160) or a different tool (160). Tools (160) can be stored on a tray (162) or other type of tool storage.

[0016] Fig. 1B schematically shows a system (102) of a computer-assisted system (100). As already mentioned, the computer-assisted system (100) can be a computer-assisted medical system, such as a surgical robotic system, or a non-medical system, such as a computer-assisted industrial or leisure system. The system (102) can include one or more computing systems (142). A computer system (142) can be used to process inputs provided by a user to the user control system (120). A computer system (142) can further be used to provide an output, e.g., a video image, on the display (144). One or more computing systems (142) can further be used to control the robotic manipulation system (130).

[0017] A computing system (142) may include one or more computer processors, non-persistent memory (e.g., volatile memory such as RAM, cache memory), persistent memory (e.g., a hard disk, an optical drive such as a CD drive or a DVD drive, flash memory, etc.), a communications interface (e.g., a Bluetooth interface, an infrared interface, a network interface, an optical interface, etc.), and numerous other elements and functionalities.

[0018] A computer processor of a computing system (142) may be an integrated circuit for processing instructions. The computer processor may, for example, be one or more cores or microcores of a processor. The computing system (142) may also include one or more input devices, such as a touchscreen, a keyboard, a mouse, a microphone, a touchpad, an electronic pen, or any other type of input device.

[0019] A communication interface of a computing system (142) may include an integrated circuit for connecting the computing system (142) to a network (not shown) (e.g., a local area network (LAN), a wide area network (WAN) such as the Internet, a mobile network, or another type of network) and / or to another device, such as another computing system (142).

[0020] Furthermore, the computing system (142) may include one or more output devices, such as a display device (e.g., a liquid crystal display (LCD), a plasma display, a touchscreen, an organic LED display (OLED), a projector, or other display device), a printer, a speaker, external memory, or another output device. One or more of the output devices may be the same as or different from the input device(s). There are many different types of computing systems, and the aforementioned input and output device(s) may take other forms.

[0021] Software instructions in the form of computer-readable program code for carrying out embodiments of the disclosure may be stored, in whole or in part, temporarily or permanently, on a non-transitory computer-readable medium such as a CD, DVD, storage device, floppy disk, tape, flash memory, physical memory, or other computer-readable storage medium. In particular, the software instructions may correspond to computer-readable program code that, when executed by one or more processors, is configured to carry out one or more embodiments of the invention.

[0022] A computing system (142) may be connected to or part of a network. The network may include multiple nodes. Each node may correspond to a computing system (142) or a group of nodes. For example, embodiments of the disclosure may be implemented on a node of a distributed system that is connected to other nodes. As another example, embodiments of the invention may be implemented on a distributed computing system having multiple nodes, where each part of the disclosure may be located on a different node within the distributed computing system. Furthermore, one or more elements of the aforementioned computing system (142) may be located at a remote location and connected to the other elements via a network.

[0023] The robotic manipulation system (130) may use a tool (160) comprising an imaging device (e.g., a monoscopic or stereoscopic endoscope, an ultrasound probe in a medical example) to acquire images of the workspace and output the acquired images to an auxiliary system (140). Similar to other tools (160), a tool with an imaging device has a mechanical interface (not shown) via which the imaging device can be coupled to the manipulator arm (150). The mechanical interface of different tools (160), e.g., the tool with the imaging device, may be the same or different from one another. Accordingly, a mechanical adapter may be used, if appropriate, to couple a tool (160) to the manipulator arm (150). Alternatively, a specific tool (160), e.g.,a special imaging tool, may be attached to a manipulator arm (150) specifically designed to accommodate such tools (160). The auxiliary system (140) may process the acquired images in various ways prior to subsequent display. For example, the auxiliary system (140) may overlay the acquired images with a virtual control interface before the combined images are displayed to the user via the user control system (120). The robotic manipulation system (130) may output the acquired images for processing external to the auxiliary system (140). One or more separate displays (144) may also be coupled to a computing system (142) and / or the auxiliary system (140) to display images, such as images of the surgical site or other related images, locally and / or remotely.

[0024] Fig. 2 shows a perspective view of an exemplary user control system (120) that can be used as part of the computer-based system (100). The user control system (120) includes a left-eye display (202) and a right-eye display (204) for providing the user (192) (in Fig. 1A) to present a coordinated stereo view of the workspace that enables depth perception. The user control system (120) further includes two input control devices (210) that in turn control the (in Fig. 1A) to manipulate one or more tools. Fig. While Figure 2 illustrates the user control system (120) in the form of a console, an integrated display, and input control devices (210) mechanically connected to the console, other implementations of the user control system (120) may also include systems in other formats. For example, user control systems may include physically separate displays, one, two, three, or more input control devices (210), and / or input control devices (210) that are not mechanically connected to the rest of the user control system.

[0025] Fig. Figure 3 shows a perspective view of the auxiliary system (140). The auxiliary system (140) may be communicatively coupled to one or more imaging devices comprising one or more tools (160) and may include a processor (not shown) to process captured or received images for display, such as on a display of a user control system (120) or on another locally and / or remotely located suitable display. For example, when a stereoscopic or depth-capable imaging device is used, the auxiliary system (140) may process the captured images to present coordinated stereo images or depth-enhanced images of the workspace.

[0026] Fig. 4A shows a robotic manipulation system (130) with multiple manipulator arms (150), each manipulator arm (150) configured to carry a tool (160) on a distal portion of the manipulator arm (150). The illustrated robotic manipulation system (130) includes four manipulator arms (150), each of which can be used to carry one or more tools. A more detailed description of a manipulator arm (150) is provided below with reference to Fig. 5, and a more detailed description of a tool (160) is given below with reference to Fig. 6. In minimally invasive medical examples, the tools (160) may be positioned and manipulated through an opening, such as natural openings or incisions in the patient, such that a distant kinematic center is maintained at the incision; this may help reduce the required size of the opening, collisions or forces acting on the tissue surrounding an opening, etc. Images of the workspace may include images of the distal ends of the tools (160) when the tools (160) are positioned within the field of view of an imaging device that includes a tool (160).

[0027] A variety of tools (160) of different types and with different end effectors (for tools with end effectors) can be used. One or more of the tools (160) can be removed and / or replaced during a procedure.

[0028] In minimally invasive surgical scenarios, an elongated shaft of a tool (160) allows the end effectors and the distal end of the shaft to be inserted distally into a surgical workspace through a minimally invasive opening, such as a natural orifice or an incision. The surgical workspace can be insufflated. Movements of the end effectors within the patient are often accomplished, at least in part, by pivoting the tool (160) about the location where the shaft is advanced through the minimally invasive opening. Accordingly, the manipulator arms (150) can move the proximal portion of the tool (160) outside the patient such that the shaft extends through the minimally invasive opening to enable desired movement of the end effector. Consequently, the manipulator arms (150) can be moved outside the patient.

[0029] Fig. 4B shows a robotic manipulation system (170) configured to carry tools (172) according to one or more embodiments. Each of the tools (172) is mounted on a manipulator arm (176) arranged on a support arm (178). In a medical scenario, a sterile barrier (in Fig. 4B not shown) with a drape and instrument adapters between a patient (not shown) and the support arm (178). The support arm (178) and the manipulator arms (176) can thus be arranged outside a sterile environment for the patient, while the tools (172) are arranged within the sterile environment.

[0030] As in connection with Fig. 4A, the tools (172) may vary in structure and purpose, but may be removable, replaceable, and / or interchangeable. Each tool (172) generally includes an end effector (180) and a shank (182). The end effectors (180) may be differently designed to implement various functions, including those associated with Fig. 6. The manipulator arms (176) may include actuators such as drive motors that provide mechanical power to actuate mechanical structures in the tools (172).

[0031] Fig. 5 shows an example of a manipulator assembly (500) according to embodiments of the present disclosure. A manipulator assembly (500) includes a manipulator arm (502) and may further include a tool mounted on the manipulator arm (502) ( Fig. 5 shows only one axis of the tool (e.g., 520), not the tool itself). Therefore, the term "manipulator assembly (500)" may in some cases be used for the manipulator arm (502) with the tool and in other cases for the manipulator arm (502) without the tool. The manipulator assembly (500) may include other components. As described above, during operation, the manipulator arm (502) generally carries a tool (520) and executes movements of the tool (520). In the Fig. In the example shown in Figure 5, the manipulator arm (502) includes a tool holder (514) to facilitate removal and replacement of one or more tools (520).

[0032] As with reference to Fig. 4A and Fig. 4B, in some embodiments, the manipulator arms (e.g., (502), other manipulator arm designs) are mounted proximally to a base of the manipulation system (e.g., (130), (170)). Alternatively, manipulator arms (502) may be mounted on separate bases that may be independently movable; for example, one or more manipulator arms (502) may be mounted on single manipulator arm carts, with attachment structures for direct or indirect mounting to an operating table or at one or more locations (e.g., by clamping to a rail or other component, by mounting to the wall or floor, etc.). Typically, a manipulator arm (502) includes a plurality of links and associated joints extending between the proximal base and the distal portion of the manipulator arm (502).

[0033] In embodiments such as those shown in Fig. 5, the manipulator arm (502) includes one or more joints (such as the rotary joints J1, J2, J3, J4, and J5, and the prismatic joint J6) that couple one or more links (504, 506, 508, and 510). A link (510) of the manipulator arm (502) may be configured to couple to a cannula (516) through which the shaft of the tool (520) extends, and the link (510) may include a tool holder (514) to which the tool is attached. In the Fig. In the example shown in Figure 5, the degrees of freedom of the tool (520) are actuated by actuators of the manipulator arm (502). These actuators can be integrated into the tool holder (514), or their drive forces or torques can be transmitted to the tool (520) via the tool holder (514).

[0034] The joints of the manipulator arm, in their combination, may or may not provide the manipulator arm with redundant degrees of freedom. A manipulator arm with one or more redundant degrees of freedom has multiple joints such that the multiple joints can be moved into a range of different configurations for a given position and / or orientation of a portion of the manipulator arm or an abstract feature relative to a portion of the manipulator arm (e.g., a remote center of motion (PP) at a location defined relative to a distal portion of the manipulator arm). For example, a manipulator arm can be maneuvered into different configurations while an end effector of a tool coupled to the tool holder, a remote center of motion, and / or another feature maintains a particular state.Examples of states that are maintained are a specific position, orientation and / or velocity of the end effector.

[0035] Fig. 6 shows an example of a tool (600) (also called an instrument (600)) according to one or more embodiments. The tool (600) includes a shaft (610) and an end effector (640) located near a first end of the shaft (610). A housing (630), arranged to releasably couple the tool (600) to a manipulator arm (e.g., manipulator arm (150, 176, 502)), is located at an opposite end of the shaft (610). In the illustrated implementation, the end effector (640) has six degrees of freedom of movement relative to the housing (630).Specifically, the six degrees of freedom may correspond to the following: pitch and yaw rotations of a portion of the end effector (640) about two respective vertical axes (641) and (642) associated with a first joint or wrist mechanism (651); pitch and yaw rotations or movement of jaws (652) relative to two respective vertical axes (643) and (644) associated with a second joint or wrist mechanism (620); opening or closing movement (653) of jaws (652) for "grip" actuation; and "roll" rotations (692) of the instrument shaft (610) about its insertion axis (612). In the example shown, the insertion axis is parallel to a central axis of the instrument shaft (610). Other tools may have more, fewer, or different degrees of freedom of movement than that shown in . Fig. 6 without departing from the disclosure. The tool (600) is designed for releasable mounting to a manipulator arm. The manipulator arm includes a prismatic joint (J6) that can be driven to translate the tool mounted on the tool holder along an axis, which can be an extension and retraction axis or an insertion axis (612). The housing (630) can include physical input elements that are rotatable or translatable to drive joints of the tool (600). An example of this is described in U.S. Pat. No. 6,394,998, entitled "Surgical Tools for Use in Minimally Invasive Telesurgical Applications." The manipulator arm (e.g., 150, 176, 502) can include drive elements such as discs or sliders or projections for coupling to the physical input elements to drive the tool (600). The drive elements can be controlled by actuators, e.g.Electric motors driven by inputs from the associated input control devices (e.g. input control devices (210) in . Fig. 2) respond to drive the tool (600) according to the movement of the input control devices (210) or another control signal, e.g., to move the end effector (640) to a desired orientation and / or position. Furthermore, appropriately positioned sensors, e.g., encoders, potentiometers, etc., may be provided to enable the measurement of the joint positions of the tool (600) or the manipulator arm (e.g., (150), (176), (502)). The actuators and sensors may be located in the tool (600), in the tool holder (e.g., 514), in the manipulator arm (e.g., (150), (176), (502)), or elsewhere.

[0036] Various tools (600) may not be equipped with end effectors or may be equipped with various end effectors (640) with different geometries (e.g., different shapes or sizes), different degrees of freedom, and / or different functions. An end effector may have a single finger or two or more fingers. Examples of single-finger end effectors include, without limitation, scalpels, cautery electrodes, irrigation or suction devices, endoscopes (with or without a wrist), etc. Examples of two-finger end effectors include, without limitation, forceps, clip applicators, scissors, dissecting tools, forceps, graspers, cautery tools with jaws, needle drivers, etc., or the like.The fingers of the end effector (640) may be individually angularly displaceable, allowing not only opening and closing of the end effector, but also angular displacement to change the orientation of the end effector (640) as a whole relative to another part of the tool (e.g., the wrist mechanism (620, 651), the shaft (610), etc.).

[0037] While Fig. 1A, Fig. 1B, Fig. 2, Fig. 3, Fig. 4A, Fig. 4B, Fig. 5 and Fig. 6 illustrate various physical configurations of components of exemplary computer-based systems, other configurations may be used without departing from the scope of the invention. For example, while a particular configuration of a robotic manipulation system with manipulator arms is shown, embodiments of the disclosure are generalizable and applicable to any type of robotic manipulation system, e.g., with a single manipulator arm holding a single tool, with a single manipulator arm holding multiple tools, etc. As another example, the functionality performed by a single component may be performed by two or more components.In addition, although the components are described in the context of surgical scenarios, embodiments of the disclosure may be equally applicable to other areas involving robotic manipulation.

[0038] Fig. 7A shows an example of a control architecture for controlling a manipulator assembly having a manipulator arm to which a tool may be mounted, according to one or more embodiments. Those skilled in the art will understand that other control architectures may be used without departing from the disclosure. Furthermore, in the illustrated control architecture, certain signals (e.g., positions) are exchanged between blocks of the control architecture. Other signals (e.g., velocities, accelerations, forces, etc.) may also be used without departing from the disclosure. Furthermore, the control architecture may implement one, two, three, or more different modes (not shown). For example, in a "follow mode," a task is performed by a manipulator assembly under user-operated remote control of input control devices (210), as in Fig. 2. The joint(s) of the robotic manipulator assembly may be position-controlled, velocity-controlled, etc., and may or may not be retractable depending on the physical design of the manipulator assembly and the control scheme. As another example, in a "tool change" mode, one or more joints of a manipulator assembly may be "floating," allowing an assistant to easily move those one or more joints externally, e.g., by retracting those one or more joints. A floating joint may be retracted by an externally applied force without any control algorithm or braking force to oppose the retraction. As another example, in a "clutch" mode, one or more active joints of a manipulator assembly may be made floating by being controlled to yield to external manipulation.As a specific example, in a “clutch mode,” a commanded position for a floating joint can be periodically updated to the current position to support external manipulation.

[0039] Various types of "follow," "tool change," "clutch," or other modes may be implemented. For example, in one embodiment of the disclosure, in a clutch mode, the system floats one or more joints of the manipulator arm such that externally applied forces on the manipulator arm slightly move a remote center of the manipulator arm relative to a world reference frame, and the manipulator arm is not controlled to simultaneously maintain a position of the end effector relative to the world reference frame. As another example, in another embodiment of the disclosure, in a clutch mode, the system controls one or more joints of a manipulator arm such that externally applied forces on the manipulator arm slightly move a remote center of the manipulator arm relative to a world reference frame, while preventing movement of the tool or end effector relative to the world reference frame.A system may implement any combination of reversible or non-reversible modes, including one or more of the modes described above and additional modes, without departing from the disclosure.

[0040] A user can apply a force to a distal link of the floating joint, causing the floating joint to retract. A floating joint can be controlled to provide gravity compensation, friction compensation, and / or other characteristics, such as a specific degree of damping.

[0041] During operation of a manipulator assembly, a combined control mode can also be implemented. For example, in one control mode, some joints can be position-controlled to resist or retract from external articulation of those joints, while other joints can be floating and facilitate the external articulation of those other joints. Also, one or more joints of the manipulator assembly can be passive, meaning they are not position- or velocity-controlled at all (but perhaps with fully or partially applied brakes). Passive joints can be manually operated. Joints can also include joint sensors so that the overall kinematics of the manipulator assembly can be maintained. In some embodiments, passive joints can include actuators for gravity compensation, friction compensation, or other purposes that do not involve actively driving the movement of the passive joint.

[0042] In one or more embodiments, the joint movements of the manipulator assembly are controlled by driving one or more joints through a controller using commands to actuators (e.g., motors, solenoids, etc.) of the manipulator assembly, with the joint movements being calculated by a processor of the controller. Mathematically, the controller may perform at least some of the calculations of the joint commands using vectors and / or matrices, some of which may have elements corresponding to positions, velocities, and / or forces / torques, etc., of the joints. The range of alternative joint configurations available to the processor may be conceptualized as a joint space.For example, the joint space may have as many dimensions as the manipulator assembly has degrees of freedom, and a particular configuration of the manipulator assembly may represent a particular point in the joint space, where each coordinate corresponds to a joint state of an associated joint of the manipulator assembly.

[0043] As used herein, the term "state" of a joint or joints refers to the control variables associated with the joint(s). For example, the state of an angle joint may refer to the angle that joint subtends within its range of motion, the angular velocity of the joint, and / or the angular acceleration of the joint. Similarly, the state of an axial or prismatic joint may refer to the axial position of the joint, its axial velocity, and / or its axial acceleration. While one or more of the controls described herein include position controls, they often also have velocity control aspects. Alternative embodiments may rely primarily or entirely on velocity controllers, force controllers, acceleration controllers, etc., without departing from the disclosure.Many aspects of control systems that can be used in such devices are described in more detail in U.S. Pat. No. 6,699,177, the entire disclosure of which is incorporated herein by reference. As long as the described movements are based on the associated calculations, the calculations of the joint movements and the movements of an end effector described herein can be performed using a position control algorithm, a velocity control algorithm, a combination of both, etc.

[0044] The control architecture (700A) of Fig. 7A includes a controller (710) that drives actuator mechanisms (790) of the manipulator assembly based on a commanded movement (720). Any number of actuator mechanisms (790) may be driven. An actuator, in combination with other elements such as sensors or gears, pulleys and cables or wires and / or other transmission elements, may form an actuator mechanism of a joint, and the joint state may be changed by actuation by the actuator mechanism.

[0045] The commanded motion (720) may be a commanded position and / or velocity of one or more features in the workspace, which may be modeled in Cartesian coordinate space (referred to herein as Cartesian space). The commanded motion (720) may be, for example, a motion command received from the user control system (120) (e.g., in the form of a position and / or velocity) or any other motion command for one or more features of the manipulator arm or a tool coupled to the manipulator arm, or a reference thereto. A feature may be any feature physically located on the manipulator assembly or an abstraction not physically related to the manipulator assembly (e.g., a point or plane related to the manipulator assembly) that may be used to define a control frame to be articulated using control inputs.Examples of features on the manipulator assembly include features of a tool (e.g., an end effector tip, a central point on the end effector, or a clevis of the end effector), a feature of the manipulator arm (e.g., a tool holder configured for coupling with a removable tool), etc. Another example of a feature of the manipulator assembly is a reference point in empty space that is exactly a specific distance and angle away from a tip of the tool.

[0046] The controller (710) may include a top-level controller (730), a reverse kinematics controller (740), a joint controller (750), and a forward kinematics model (760). Each of these components is described below.

[0047] The top-level controller (730) includes, according to one or more embodiments, instructions in the form of computer-readable program code to receive the commanded movement (720) and to convert the commanded movement (720) into positions in a Cartesian reference frame. The steps performed to convert the commanded movement (720) into Cartesian positions depend on the format in which the commanded movement (720) is provided.

[0048] The reverse kinematics controller (740) converts commanded Cartesian positions into commanded joint positions (742) (e.g., translational positions for prismatic joints, joint angles for rotary joints, etc.) according to one or more embodiments. The reverse kinematics controller operations may be performed in the velocity domain and calculate the commanded joint velocities. The reverse kinematics controller (740) may integrate the calculated joint velocities to obtain desired joint positions (742).

[0049] The Cartesian error (732) may be a combination of the Cartesian positions provided by the top-level controller (730), as previously discussed, and the Cartesian positions provided by a forward kinematics model (760), as discussed below. More specifically, the Cartesian positions provided by the forward kinematics model (760) may represent an estimate of an actual or current position (e.g., of an end effector) of the manipulator assembly in Cartesian space. This estimate may be subtracted from the Cartesian positions representing the commanded motion to obtain the difference to be compensated, which is used as the control input for the reverse kinematics controller (740).

[0050] While there generally is no closed-form relationship mapping a desired Cartesian spatial position to an equivalent joint-space position, a closed-form relationship typically exists between the Cartesian spatial velocity and the joint-space velocities. The kinematic Jacobian matrix is ​​the matrix of partial derivatives of the Cartesian spatial position elements with respect to the joint-space position elements. The kinematic Jacobian matrix (J) can be used to map joint-space velocities (dq / dt) to velocities in Cartesian space (dx / dt), e.g., to end-effector velocities.

[0051] Therefore, even if there is no closed form mapping between entry and exit positions, velocity mappings can be used iteratively by the reverse kinematics controller (740) to implement movement of the manipulator assembly based on a commanded trajectory.

[0052] Each of the joint controllers (750) converts a received commanded joint position (742), such as a linear or angular joint position, into an actuator command (752) to drive one of the actuator mechanisms (790) and produce a joint movement (792), according to one or more embodiments. The actuator command (752) can be in any form suitable for the actuator mechanism (790). For example, the actuator command (752) can comprise a voltage, a digital value, or another signal transmitted to a motor controller of a motorized actuator mechanism. A joint controller (750) can be used to control each actuator mechanism (790). The joint movements (792) of all actuator mechanisms can produce, through the kinematics of the manipulator assembly, a movement of the manipulator arm according to the commanded movement (720). Fig. Figure 7B shows an example of a joint control (750).

[0053] The forward kinematics model (760) converts the sensed joint states (754) into other forms, such as joint positions or velocities into Cartesian positions or velocities, as previously described, according to one or more embodiments.

[0054] Any part of the controller (710) or the entirety of the controller (710) may be implemented in hardware, software, or a combination of hardware and software. For example, the controller (710) may be implemented in whole or in part in the form of computer-readable program code configured to perform the operations described for the controller (710). The controller (710) may be implemented on one or more computing systems. These one or more computing systems may be based on digital signal processors (DSPs), central processing units (CPUs), etc. An example of a computing system is described with reference to Fig. 1B.

[0055] In one or more embodiments, the controller (710) is further configured to perform at least one of the Fig. Configured according to the steps described in section 8.

[0056] Fig. 7B illustrates a control architecture (700B) of a joint controller according to one or more embodiments. In this example, a closed-loop PD (proportional-derivative) control structure is used to control a joint position based on a commanded joint position.

[0057] The joint controller may receive a feedback signal in the form of a sensed joint state (754) (particularly, in this example, a sensed joint position in the case of the control architecture (700B)) from the associated actuator mechanism (790) to enable closed-loop control. The joint state (754) may be derived from signals originating from a sensor attached to the joint. Such a sensor may, for example, be an incremental encoder, a shape sensor, or a Hall sensor of the joint or actuator mechanism. A state observer or estimator (not shown) may be used. The PD control structure uses two control gains (K P , K D) acting on a difference between the commanded joint position (742) and the sensed joint position (i.e., an error signal), or derivatives thereof, to generate an actuator command (752). In one or more embodiments of the disclosure, the actuator command (752) is limited, and accordingly, the resulting joint torque or force is also limited. The limit may be based on hardware limitations, such as a maximum allowable motor current. The limit may also be software-configurable.

[0058] Accordingly, the motor current (and the resulting motor torque or force) can increase linearly with the position deviation between the commanded joint position (742) and the sensed joint position (754), as specified by the proportional control gain (KP), only until the saturation limit is reached. Beyond this limit, the motor current is constant. A higher K Pcan result in a relatively small position error being sufficient to reach the saturation limit, while a low K P may result in a relatively large position error being required to reach the saturation limit. In one embodiment of the disclosure, a relatively high K Pused to achieve responsive position control of the joint with a limited steady-state error. Accordingly, an increase in the position error can quickly lead to reaching the saturation limit. While the control architecture (700B) uses a proportional-derivative (PD) controller, other controllers such as proportional-integral-derivative (PID) controllers, full-state feedback, sliding mode, or various other control schemes may be used without departing from the disclosure. While control of a joint position is illustrated, other variables such as velocity, torque, or force may also be controlled without departing from the disclosure.

[0059] The previously described retraction of a joint can occur in several different control modes to control the actuator mechanism associated with the joint. An implementation can be configured with one, two, three, four, or more control modes that allow retraction of a joint. For illustration purposes, the following text describes three different example control modes that allow retraction of a joint. These control modes are based on the control architecture (700B) in Fig. 7B, although other control architectures are also possible. A system can be configured with one of these three control modes, two of these three control modes, all three control modes, or any other combination of control modes that is the same as or different from the three control modes described below.

[0060] For example, a system may be implemented with a reversible control mode that includes a slip control mode. The slip control mode is described in more detail in U.S. Provisional Patent Application No. 62 / 826,780 and PCT Patent Application No. PCT / US2020 / 025481, the full disclosures of which are incorporated herein by reference. For example, assume that PD controllers, as described in Fig. 7B, can be used to control the actuator mechanism of a manipulator arm or a manipulator assembly that includes the manipulator arm and a tool. A PD controller can be used to control an actuator mechanism of a manipulator arm segment. The control can, for example, consist of maintaining the joint in a commanded joint position (e.g., the commanded position can be stored as a commanded joint state (742) in Fig. 7B). As with reference to Fig. 7B, the proportional control gain of the PD controller may respond to a deviation of the actual joint position (e.g., the sensed or estimated joint position) from the commanded position. In response to the deviation, an actuator command may be generated or modified to drive the actuator mechanism, and the actuator mechanism controlled by the actuator command may generate a corresponding torque or force (e.g., a motor torque or force provided at the actuator output, or a joint torque or force). For example, an actuator command may include or cause a commanded current for a motor actuator and induce a torque proportional to the commanded current. Accordingly, a larger difference between the commanded joint position and the sensed joint position results in greater torque produced by the actuator mechanism.In this way, a PD controller-based control loop can partially mimic the characteristics of a linear spring: the further apart the commanded and actual joint positions are, the more energy is stored in the spring, as the PD controller must compensate for the difference with increased force. The spring coefficient can be adjusted by the proportional control gain (K). P ). In one or more embodiments, a defined threshold is used to distinguish two behaviors of the joint: (1) If the deviation does not exceed the defined threshold, the PD controller compensates for the deviation by driving the actuator mechanism in a direction opposite to the deviation. In other words, the actuator is controlled based on the commanded state. (2) If the deviation exceeds the defined threshold, the commanded state can be updated so that it is closer to the actual state, thereby reducing the deviation to an acceptable level below the defined threshold. In other words, the commanded state can be adjusted to produce an adjusted commanded state in which the difference between the adjusted commanded state and the actual state is smaller than the deviation. The adjusted commanded state is then used to control the actuator.The adjusted commanded state can be selected such that, for example, a saturated output force / torque is maintained while minimizing the deviation between the adjusted commanded and the actual state, with the defined threshold determining the saturated output force / torque.

[0061] The defined threshold can be set relative to a commanded position or, more generally, a commanded state. In this configuration, if a force or torque associated with an external joint (e.g., when a user applies a force to a link distal from the joint) results in a deviation of the sensed joint position from the commanded joint position that exceeds the defined threshold, the joint can be retracted. If a force or torque associated with an external joint results in a deviation of the sensed joint position from the commanded joint position that does not exceed the deviation threshold (e.g., as a result of a lower force application), the joint can spring-loadedly counteract the force without changing the commanded joint position.The amount of force required to effect a change in the commanded position can depend on various factors. For example, more force must be applied at a higher defined threshold than at a lower defined threshold. If the defined threshold is set to a very low value (close to zero), reversing may be possible with very little force or torque applied to the joint. Furthermore, a higher proportional control gain (K) would require a higher force to be applied. P ) more force is applied than with a lower error threshold, since K P is responsible for the spring-like characteristics of the joint below the error threshold, whereby a higher K P a stiffer spring is implemented. Accordingly, the characteristics of the joint's return behavior can be adjusted by adjusting the error threshold and / or K P be modulated.

[0062] For example, a system can be implemented with a reversible control mode that includes a position hold mode. For example, assume that PD controllers, as in Fig. 7B, for controlling the actuator mechanism of a manipulator arm or a manipulator assembly including the manipulator arm and a tool. A PD controller may be used to control an actuator mechanism configured to move a first joint of the manipulator arm. For example, the controller may control the actuator mechanism such that the joint is maintained in a commanded joint position (e.g., the commanded position may be stored as a commanded joint state (742) in Fig. 7B). As with reference to Fig. 7B and as discussed for the slip control mode, the proportional control gain of the PD controller may act on a deviation of the actual joint position (e.g., the sensed or estimated joint position) from the commanded position. In response to the deviation, an actuator command may be generated or modified to drive the actuator mechanism; the actuator mechanism controlled by the actuator command may generate an appropriate amount of linear force or rotational torque (e.g., torque provided at the output of the actuator or a driveline driven by the actuator). Accordingly, a larger difference between the commanded joint position and the sensed joint position results in the generation of a greater force or torque by the actuator mechanism, as previously described for the slip control mode.In one or more embodiments, the PD controller is also configured to prevent a further increase in force or torque once the deviation exceeds a defined threshold, such that a plateau is reached. This plateau beyond the defined threshold may be substantially position and velocity independent. In one or more embodiments, the PD controller is not configured to have such a defined threshold, or it is not configured to prevent the force or torque from increasing when the deviation exceeds the defined threshold.

[0063] For example, a system may be implemented with a reversible control mode that includes a clutch control mode. In one embodiment, for example, PD controllers as described in Fig. 7B, is used to control the actuator mechanism of a manipulator assembly. A PD controller can be used to control an actuator mechanism of a manipulator arm segment. As shown in Fig. As shown in Figure 7B, the commanded joint position (742) may be adjusted to match the sensed joint position (754) when an actuator mechanism is in a clutch control mode. Since the proportional control gain of the PD controller is based on a deviation of the actual joint position (e.g., the sensed or estimated joint position) from the commanded joint position, the PD controller may generate a zero command (e.g., zero force, zero torque, zero current, etc.). The zero command may be modified to allow for gravity and / or friction compensation, and as a result, the joint associated with the actuator mechanism may float, as previously described.

[0064] The following sections describe a method for providing controlled resistance in retractable joints based on the discussed control modes.

[0065] Fig. 8 shows a flowchart according to one or more embodiments. The flowchart of Fig. Figure 8 shows a method for operating a robot system according to one or more embodiments. More specifically, the method can be used to implement controlled resistance in retractable joints. One or more of the steps in Fig. 8 can be executed by various components of the systems previously described with reference to Fig. 1A, Fig. 1B, Fig. 2, Fig. 3, Fig. 4A, Fig. 4B, Fig. 5 and Fig. 6. In these figures, specific manipulator arms and specific tools are described, where the manipulator arms and tools have specific degrees of freedom. However, the methods described below are not limited to a specific configuration of manipulator arms, tools, and / or degrees of freedom. Instead, the methods are applicable to any type of manipulator arm, paired with any type of tool, used in any type of scenario. Furthermore, one or more of the steps in Fig. 8 on the control modes of the Fig. 7A and Fig. 7B described control architecture.

[0066] The description of the procedure is followed by a discussion of various applications and advantages.

[0067] While the various steps in the flowchart are presented and described sequentially, those skilled in the art will recognize that some or all of the steps may be performed in different orders, combined or omitted, and some or all of the steps may be performed in parallel. Furthermore, additional steps may be performed. Furthermore, the steps may be performed actively or passively. For example, some steps may be performed by polling or interrupt-driven in accordance with one or more embodiments of the invention. For example, determining steps do not require processing of an instruction by a processor unless an interrupt is received indicating that a condition exists in accordance with one or more embodiments of the invention. Another example is performing determining steps by performing a test, e.g.,the verification of a data value to test whether the value matches the tested condition according to one or more embodiments of the invention. Accordingly, the scope of the disclosure should not be limited to the embodiments described in . Fig. 8 shown specific arrangement of steps.

[0068] The flowchart of Fig. Figure 8 shows a series of steps that implement a method for providing controlled resistance in retractable joints. The method can be executed repeatedly, e.g., in a loop. Although the flowchart of Fig. 8 shows steps performed for a single joint, the steps may be performed for multiple joints without departing from the disclosure.

[0069] In step 800, a control mode for controlling an actuator mechanism of a joint is selected. The flowchart of Fig. Figure 8 shows two control modes for the method: a first control mode and a second control mode. There may be one or more additional control modes without departing from the disclosure. The selection of a control mode may be made by a user, e.g., by specifying the control mode. Alternatively, the control mode may be selected by a computer system, e.g., by the top-level controller of the control architecture of Fig. 7A. A control mode can be selected for an actuator mechanism of a single joint or for actuator mechanisms of multiple joints. For example, as discussed previously, multiple joints can be "floating" when in a clutch control mode.

[0070] In step 810, depending on which control mode is selected, execution of the method continues with step 820 to operate the joint in a first control mode, or with step 830 to operate the joint in a second control mode. In one or more embodiments, both the first control mode and the second control mode allow external articulation (e.g., as a result of a force applied to a distal link of the joint) to reconfigure the manipulator arm by retracting the joint.

[0071] In step 820, the controller commands the actuator mechanism to operate the joint in the first control mode. Operating the joint in the first control mode involves executing steps 822 and 824, and optionally step 826.

[0072] In step 822, the joint is operated in a servo control mode. The servo control mode may be, for example, the slip control mode or the position hold mode, as previously described with reference to Fig. 7B, or any other feedback-controlled, reversible control mode.

[0073] In step 824, above a first speed threshold, a first speed-dependent resistance (e.g., a motor force or torque, or a joint force or torque) is provided to oppose the retraction of the joint. For a rotary joint, the first speed-dependent resistance may comprise a rotational force (e.g., a torque). For a prismatic joint, the first speed-dependent resistance may be a linear force (e.g., a force). In one embodiment, the first speed-dependent resistance simulates a speed-dependent damping behavior. The speed-dependent damping behavior may have any characteristic. For example, the first speed-dependent resistance may increase linearly or nonlinearly (e.g., quadratically or exponentially) with the speed of retraction exceeding the first speed threshold.Furthermore, the slope of the velocity-dependent damping response can be parameterized to allow for a stronger or weaker velocity dependence. Additional details regarding the velocity-dependent damping behavior are provided below with reference to . Fig. 9 is given.

[0074] In step 826, at or below the first speed-dependent threshold, a speed-independent resistance (e.g., a motor force or torque or a joint force or torque) may be provided to counteract the retraction of the joint. Step 826 is an optional additional step for the example in Fig. 8. Speed-independent resistance can be provided in slip control mode, as previously described. The level of speed-independent resistance can be set as a parameter. This parameter can be used to set the threshold up to which the PD controller-based control loop exhibits spring-like characteristics: the further apart the commanded and actual joint positions are allowed to be based on the parameter, the more energy can be stored in the spring, resulting in higher speed-independent resistance. If the acceptable difference between the commanded and actual joint positions is set to zero, the speed-independent resistance can be zero or minimal (e.g., based on friction effects that exist regardless of the selected control mode).

[0075] In step 830, the controller commands the actuator mechanism to operate the joint in the second control mode. Operating the joint in the second control mode involves executing step 832 and, optionally, step 834.

[0076] In step 832, the joint is operated in a clutch control mode as previously described with reference to Fig. 7B discussed.

[0077] In step 834, above a second speed threshold, a second speed-dependent resistance is provided to counteract the retraction of the joint. The second speed threshold may be different from the first speed threshold, and / or the second speed-dependent resistance may be different from the first speed-dependent resistance. In one embodiment, the second speed-dependent threshold is higher than the first speed-dependent threshold. In one embodiment, the second speed-dependent resistance, like the first speed-dependent resistance, simulates a speed-dependent damping behavior and may have any characteristic as previously described. For a rotary joint, the second speed-dependent resistance may include a torque.For a prismatic joint, the second velocity-dependent resistance may include a force. Step 834 is an optional additional step for the example in . Fig. 8.

[0078] In one or more embodiments, the first speed threshold and / or the second speed threshold are below a back electromotive force (back EMF) speed threshold. Accordingly, a user would experience the first and / or second speed-dependent resistance before reaching reversing speeds that would result in back EMF effects provided by the actuator, as previously discussed. The first and / or second speed-dependent resistance may provide haptic feedback to the user. In some embodiments, the user may use the first and / or second resistance as an indication that a further increase in reversing speed is undesirable, and the user may choose to avoid a further increase in reversing speed.Accordingly, the presence of the first and / or second speed-dependent resistor can help the user avoid reaching reversing speeds beyond the back EMF speed limit.

[0079] With reference to Fig. 9, a diagram (900) is shown according to one or more embodiments, illustrating resistance-velocity profiles for various control modes when the position is already saturated. The diagram (900) includes a first profile (920) associated with the previously described first control mode of Fig. 8 may be associated. In the Fig. 9, the first profile (920) includes a portion at or below a first speed threshold (926) with a first speed-independent resistance (924), a portion at or above the first speed threshold (926) with a first speed-dependent resistance (922). With reference to the discussion of the slip control mode with respect to Fig. 7B, the first speed-independent resistance (924) is a result of the deviation of the actual joint position from the commanded joint position exceeding the defined threshold, causing the actuator mechanism to produce a saturated output force / torque corresponding to the first speed-independent resistance (924). The graph (900) further includes a second profile (940) associated with the previously described second control mode of Fig. 8 may be associated. In the Fig. 9, the second profile (940) includes a portion above the second speed threshold (946) with a second speed-dependent resistance (942). Although not shown, the second profile (940) may have a second speed-independent resistance at or below the second speed threshold (946). The second speed-independent resistance may be lower than the first speed-independent resistance (924). The graph (900) shows an immediate transition to the first speed-dependent resistance (922) upon exceeding the first speed threshold (926) and an immediate transition to the second speed-dependent resistance (942) upon exceeding the second speed threshold (946). Instead, smooth transitions may be implemented without departing from the disclosure.The precise transition between the speed-independent and speed-dependent resistance can be realized in various ways without departing from the present disclosure, including transitions where the resistance provided by the manipulator varies continuously with speed. The first profile differs from the second profile and does not overlap or overlie it for all non-zero return speeds below the speed limit of the back electromotive force (952). In the example shown in . Fig. In the example shown in Figure 9, the slope of the first speed-dependent resistor (922) is equal to or greater than the slope of the second speed-dependent resistor (942), and the first and second profiles (920, 940) do not overlap at any point. It is understood that other slopes and / or nonlinear sections that also do not intersect may be used in other examples. Therefore, a haptic distinction is provided between a reversing in the first control mode and a reversing in the second control mode at each reversing speed until the resulting resistance reaches a level that the actuator cannot exceed (e.g., based on a maximum current for an actuator).

[0080] With reference to the Fig. 1A, Fig. 1B, Fig. 2, Fig. 3, Fig. 4A, Fig. 4B, Fig. 5 and Fig. 6, the methods described can facilitate and / or improve the use of and interaction with robot systems.

[0081] In one embodiment, the methods can be applied to haptically distinguish two or more control modes. Such haptic discrimination can be useful for providing feedback that does not require visual or auditory attention from the user. In such a scenario, the user may be able to detect a change in control modes, distinguish between control modes, or determine the current control mode based solely on the haptic discrimination of the control modes.

[0082] In a specific example relating to Fig. 6, a tool (600) has an insertion axis (612). The tool (600) can move along the insertion axis in at least two different scenarios. In a first scenario, the tool (600) moves along the insertion axis (612) as part of the operation of the tool to perform work at a target location. For example, an insertion movement along the insertion axis (612) can be performed to approach the target location with the end effector (640) of the tool (600), or a retraction movement along the insertion axis (612) can be performed to retract the end effector (640) from the location. In a second scenario, the tool moves along the insertion axis as part of a tool change operation (e.g., when the tool is removed and replaced with another tool).Although in both the first and second scenarios the movement of the tool (600) occurs along the insertion axis (612), the context in which the movement takes place is different. Different control modes can be used for the two scenarios.

[0083] For the first scenario, during the operation of the tool, the first control mode can be selected as shown in the flowchart of Fig. 8. In the first control mode, the movement of the tool along the insertion axis can be commanded (e.g., by teleoperation), allowing retraction of the tool, e.g., by a user pushing or pulling the tool along the insertion axis. Depending on the retraction speed, the user may experience speed-independent resistance to retraction or speed-dependent resistance to retraction.

[0084] For the second scenario, during the tool replacement, the second control mode can be used as shown in the flowchart of Fig. 8. In the second control mode, no movement of the tool is commanded, and the user can freely retract the tool (with no or minimal resistance) along the insertion axis to perform tool removal and / or reinsertion.

[0085] The use of different resistance-speed profiles, e.g. as in Fig. 9, provides haptic feedback to help the user distinguish or identify the current control mode of the tool moving along the insertion axis. Specifically, at lower return speeds, the user may perceive the first speed-independent resistance when in the first control mode (in this example, the tool operating mode). In contrast, in the second control mode (in this example, the tool changing mode), the user experiences little or no resistance at similar speeds.At return speeds beyond the first speed threshold, the user may notice the higher first speed-dependent resistance in the first control mode (in this example, the tool run mode), which is higher than the resistance the user would experience at the same speed in the second control mode (in this example, the tool change mode). At even higher return speeds, the user may notice back EMF resistance in the second control mode. If the first control mode were implemented without the speed-dependent resistance, the user would still feel back EMF resistance at higher speeds in the first control mode because the back EMF resistance is higher than the first speed-independent resistance. Due to the addition of the first speed-dependent resistance, as discussed in relation to . Fig.However, as discussed in section 9, the first and second control modes are haptically distinguishable at any reversing speed. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 402 433 B1

[0004] EP 2 884 993 B1

[0004] EP 2 263 595 B1

[0004] EP 2 135 637 B1

[0004] WO 2020 / 205 634 A1

[0004] WO 2020 / 028 356 A1

[0004] US 6,394,998

[0035] US 6,699,177

[0043] US 62 / 826,780

[0060] PCT / US2020025481

[0060]

Claims

[1] Computer-based system (100) comprising the following: a manipulator arm (150, 502) comprising a joint (J1, J2, J3, J4, J5, J6) and an actuator mechanism (790) configured to drive the joint (J1, J2, J3, J4, J5, J6); and a controller (710) comprising a computer processor, wherein the controller (710) is communicatively coupled to the manipulator arm (150, 502) and is configured with a first control mode and a second control mode, wherein the controller (710) in both the first control mode and the second control mode commands the actuator mechanism (790) to allow external articulation in order to reconfigure the manipulator arm (150, 502) by retracting the joint (J1, J2, J3, J4, J5, J6), wherein the first control mode differs from the second control mode at least in that the controller (710) is configured to command the actuator mechanism (790) in the first control mode to provide a first velocity-dependent resistance in response to the joint (J1, J2, J3, J4, J5, J6) being retracted at a first retraction velocity above a first velocity threshold, wherein the first velocity-dependent resistance opposes the retraction of the joint (J1, J2, J3, J4, J5, J6).wherein the controller (710) is configured to, in the second control mode, command the actuator mechanism (790) to provide a second velocity-dependent resistance in response to the joint (J1, J2, J3, J4, J5, J6) retracting at a second retraction speed above a second velocity threshold, wherein the second velocity-dependent resistance opposes the retraction of the joint (J1, J2, J3, J4, J5, J6). where the second speed-dependent resistance differs from the first speed-dependent resistance. [2] Computer-aided system (100) according to claim 1, wherein the first velocity-dependent resistance comprises a torque. [3] Computer-aided system (100) according to claim 1, wherein the first velocity-dependent resistor simulates a velocity-dependent damping behavior. [4] Computer-aided system according to claim 1, wherein the control (710) is configured to command the actuator mechanism (790) to float the joint (J1, J2, J3, J4, J5, J6) in the second control mode. [5] Computer-aided system according to claim 4, wherein the actuator mechanism (790) to make the joint (J1, J2, J3, J4, J5, J6) float is commanded to enable the joint (J1, J2, J3, J4, J5, J6) to move backwards without a control algorithm that opposes the backwards movement or without a braking force that opposes the backwards movement. [6] Computer-aided system (100) according to claim 4, wherein the second speed threshold is greater than the first speed threshold. [7] Computer-aided system (100) according to claim 1, wherein in the first control mode the controller (710) commands the actuator mechanism (790) to allow external articulation in order to reconfigure the manipulator arm (150, 502) by performing operations which include: Obtaining an actual state of the joint (J1, J2, J3, J4, J5, J6); Determining a deviation between a commanded state of the joint (J1, J2, J3, J4, J5, J6) and the actual state; in response to the deviation exceeding a defined threshold: Adjusting the commanded state to produce an adjusted commanded state, wherein a difference between the adjusted commanded state and the actual state is less than the deviation, and applying the adjusted commanded state when commanding the actuator mechanism (790); and in response to the fact that the deviation does not exceed the defined threshold: Applying the commanded state when controlling the actuator mechanism (790). [8] Computer-aided system (100) according to claim 1, wherein, in order to instruct the actuator mechanism (790) to provide the first speed-dependent resistance, the controller (710) is configured to instruct the actuator mechanism (790) to increase the first speed-dependent resistance by an amount by which the first reversing speed exceeds the first speed threshold. [9] Computer-aided system (100) according to claim 8, wherein the first velocity-dependent resistance increases linearly with the amount. [10] Computer-aided system (100) according to any one of claims 1 to 9, wherein the actuator mechanism (790) comprises an actuator with a velocity limit of the counter-electromotive force, and where the first speed threshold is below the speed limit of the counter-electromotive force. [11] Computer-aided system (100) according to any one of claims 1 to 9, wherein the actuator mechanism (790) comprises an actuator with a velocity limit of the counter-electromotive force; wherein the controller (710) is configured to: command the actuator mechanism (790) to provide the first velocity-dependent resistance to resist the retraction of the joint (J1, J2, J3, J4, J5, J6) according to a first resistance-velocity profile; wherein the controller (710) is further configured to: command the actuator mechanism (790) in the second control mode to resist the retraction of the joint (J1, J2, J3, J4, J5, J6) according to a second resistance-speed profile; and where the first resistance-speed profile differs from the second resistance-speed profile for all non-zero speeds of reversing below the speed limit of the counter-electromotive force. [12] Computer-aided system (100) according to any one of claims 1 to 9, wherein: the manipulator arm (150, 502) is configured to carry and move a tool (160, 600); and The joint (J6) provides one degree of freedom for moving the tool (160) along an insertion axis (612) into a work space. [13] Computer-aided system (100) according to any one of claims 1 to 9, wherein the controller (710) is further configured to command the actuator mechanism (790) in the first control mode to provide a speed-independent resistance that opposes the retraction of the joint (J1, J2, J3, J4, J5, J6), such that the speed-independent resistance provides a user with haptic feedback that causes the retraction, wherein the haptic feedback distinguishes the retraction of the joint (J1, J2, J3, J4, J5, J6) in the first control mode from the retraction of the joint (J1, J2, J3, J4, J5, J6) in the second control mode. [14] Computer-aided system (100) according to any one of claims 1 to 9, wherein the first speed-dependent resistance provides a user with haptic feedback that causes the joint (J1, J2, J3, J4, J5, J6) to retract in the first control mode, wherein the haptic feedback distinguishes the retraction of the joint (J1, J2, J3, J4, J5, J6) in the first control mode from the retraction of the joint (J1, J2, J3, J4, J5, J6) in the second control mode. [15] Computer-aided system (100) according to any one of claims 1 to 9, wherein the controller (710) is further configured to command the actuator mechanism (790) in the first control mode to provide a speed-independent resistance that opposes retraction when the joint (J1, J2, J3, J4, J5, J6) is retracted at a speed that does not exceed the first speed threshold. [16] Non-volatile machine-readable medium comprising a plurality of machine-readable instructions that are executed by a controller (710) by one or more processors associated with a computer system (100), wherein the computer system (100) has a manipulator arm (150, 502), the manipulator arm (150, 502) comprising a joint (J1, J2, J3, J4, J5, J6) and an actuator mechanism (790) configured to drive the joint (J1, J2, J3, J4, J5, J6), the associated processors are controlled to perform the following steps: when the controller (710) is in both first control mode and second control mode, instructions to the actuator mechanism (790) by the controller (710) to allow external articulation to move the manipulator arm (150, 502) by reversing the joint (J1, J2, J3, J4, J5, J6), When the controller (710) is in first control mode, commands are sent by the controller (710) to the actuator mechanism (790) to provide a first velocity-dependent resistance in response to the joint (J1, J2, J3, J4, J5, J6) being moved back at a first return speed above a first velocity threshold, the first velocity-dependent resistance opposing the return of the joint (J1, J2, J3, J4, J5, J6). When the controller (710) is in the second control mode, the controller (710) commands the actuator mechanism (790) to provide a second speed-dependent resistance in response to the joint (J1, J2, J3, J4, J5, J6) retracting at a second retraction speed above a second speed threshold, the second speed-dependent resistance opposing the retraction of the joint (J1, J2, J3, J4, J5, J6). where the second speed-dependent resistance differs from the first speed-dependent resistance. [17] Non-volatile machine-readable medium according to claim 16, wherein the first velocity-dependent resistance has a torque. [18] Non-volatile machine-readable medium according to claim 16, wherein the first velocity-dependent resistance simulates a velocity-dependent damping behavior. [19] Non-volatile machine-readable medium according to claim 16, wherein the control comprises: commands to the actuator mechanism (790) by the control to make the joint (J1, J2, J3, J4, J5, J6) float. [20] Non-volatile machine-readable medium according to claim 19, wherein the swimming of the joint (J1, J2, J3, J4, J5, J6) comprises: allowing the backward movement of the joint (J1, J2, J3, J4, J5, J6) without a control algorithm that opposes the backward movement or without a braking force that opposes the backward movement. [21] Non-volatile machine-readable medium according to claim 16, wherein the commands to the actuator mechanism (790) by the controller (710) to allow external articulation to reconfigure the manipulator arm (150, 502) include: Maintaining an actual state of the joint (J1, J2, J3, J4, J5, J6) by the control (710); Determining a deviation between a commanded state of the joint (J1, J2, J3, J4, J5, J6) and the actual state by the control (710); where the controller (710) performs the following actions in response to the deviation exceeding a defined threshold: Adjusting the commanded state to produce an adjusted commanded state, where the difference between the adjusted commanded state and the actual state is smaller than the deviation, and Applying the adjusted commanded state when giving commands to the actuator mechanism (790); and where the controller (710) performs the following actions in response to the fact that the deviation does not exceed the defined threshold: Applying the commanded state when giving commands to the actuator mechanism (790). [22] Non-volatile machine-readable medium according to claim 16, wherein when commanding the actuator mechanism (790) to specify the first speed-dependent resistance, the actuator mechanism (790) is commanded to increase the first speed-dependent resistance by the amount by which the first reverse speed exceeds the first speed threshold. [23] Non-volatile machine-readable medium according to claim 22, wherein the first velocity-dependent resistance increases linearly with the amount. [24] Non-volatile machine-readable medium according to any one of claims 16 to 23, wherein the actuator mechanism (790) comprises an actuator with a speed limit for the counter-electromotive force, and where the first speed threshold is below the speed limit for the counter-electromotive force. [25] Non-volatile machine-readable medium according to any one of claims 16 to 24, wherein the actuator mechanism (790) comprises an actuator with a speed limit for the counter-electromotive force: Whereby the following is included in the instructions to provide the actuator mechanism (790) with the first velocity-dependent resistance: commands to the actuator mechanism (790) by the control (710) to resist the retraction of the joint (J1, J2, J3, J4, J5, J6) according to a first resistance-velocity profile; commands to the actuator mechanism (790) by the control (710) to resist the retraction of the joint (J1, J2, J3, J4, J5, J6) according to a second resistance-speed profile, where the first resistance-speed profile differs from the second resistance-speed profile for all non-zero reverse speeds below the speed limit of the counter-electromotive force. [26] Non-volatile machine-readable medium according to any one of claims 16 to 24, wherein the manipulator arm (150, 502) is configured to hold and move a tool (160, 600); and the joint (J6) provides one degree of freedom to move the tool (160) along an insertion axis (612) in the work space. [27] Non-volatile machine-readable medium according to any one of claims 16 to 24, wherein: the controller (710) comprises the following: commanding the actuator mechanism (790) by the controller (710) to provide a speed-independent resistance that opposes the retraction of the joint (J1, J2, J3, J4, J5, J6), such that the speed-independent resistance provides a user with haptic feedback that causes the retraction, wherein the haptic feedback distinguishes the retraction of the joint (J1, J2, J3, J4, J5, J6) in the first control mode from the retraction of the joint (J1, J2, J3, J4, J5, J6) in the second control mode. [28] Non-volatile machine-readable medium according to any one of claims 16 to 24, wherein the first speed-dependent resistance provides a user with haptic feedback that causes the joint (J1, J2, J3, J4, J5, J6) to retract in the first control mode, wherein the haptic feedback distinguishes the retraction of the joint (J1, J2, J3, J4, J5, J6) in the first control mode from the retraction of the joint (J1, J2, J3, J4, J5, J6) in the second control mode. [29] Non-volatile machine-readable medium according to any one of claims 16 to 24, wherein: The control (710) comprises the following: commanding the actuator mechanism (790) by the control (710) to provide a speed-independent resistance that opposes retraction in response to the joint (J1, J2, J3, J4, J5, J6) retracting at a speed that does not exceed the first speed threshold.

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