Adaptive damper for computer-aided system

Abstract

A computer-aided system may include a manipulator arm configured to support an instrument, an input device configured to accept a user command to move the instrument, and a damping system coupled to the input device. A controller of the computer-aided system may be configured to determine an instrument power metric and an input device power metric. The controller may also determine a damping to be applied to the input device based on the instrument power metric and the input device power metric, and cause the damping system to adjust the damping applied to the input device.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Serial No. 63 / 347,304, filed on May 31, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0001] The disclosed embodiments relate to adaptive dampers for computer-assisted systems and related methods of use. Background Art

[0002] Computer-assisted electronic systems are being used more and more frequently. This is especially true in industrial, entertainment, educational and other environments. As a medical example, today's medical facilities have a large number of electronic devices in operating rooms, interventional suites, intensive care units, emergency rooms and / or similar locations. Many of these electronic devices may be capable of autonomous or semi-autonomous movement. Personnel can remotely control the movement and / or operation of follower electronic devices using one or more leader input devices located at the user control system. For example, a robotic telemedicine system allows medical personnel to remotely operate instruments and perform medical procedures from the patient's side or from a remote site. As a specific example, a minimally invasive robotic telesurgery system allows surgeons to operate on patients from the bedside or a remote site. Telesurgery generally refers to a surgical procedure performed using a surgical system, in which the surgeon uses some form of remote control, such as a servo mechanism, to manipulate the movement of surgical instruments rather than directly holding and moving the instruments by hand. In some systems having an actuator system coupled to an input device, the actuator system can be driven to provide tactile feedback through the input device. Therefore, there is a need for improved devices and methods for operating computer-assisted electronic systems. Summary of the invention

[0003] In some embodiments, a computer-assisted system includes a manipulator arm configured to support an instrument, an input device configured to accept a user command to move the instrument, a damping system coupled to the input device, and a controller including at least one processor. The controller is configured to: determine an instrument power metric indicating an amount of power of an instrument interaction, the instrument interaction including a physical interaction between at least a portion of the instrument and an instrument environment containing the instrument; determine an input device power metric indicating an amount of power of feedback provided by the input device in response to the instrument interaction; determine damping to be applied to the input device based on the instrument power metric and the input device power metric; and cause the damping system to apply damping to the input device.

[0004] In some embodiments, a method of controlling a computer-assisted system configured to support an apparatus, the computer-assisted system comprising an input device configured to control movement of the apparatus and a damping system configured to apply a force to the input device, the method comprising: determining a component of a force change at the apparatus, the component being related to a direction of motion of the input device; and in response to determining that an environmental stiffness experienced by the apparatus exceeds a threshold stiffness, determining a feedback force based at least in part on the environmental stiffness and the component of the force change. The method also includes causing the damping system to drive the input device to apply the feedback force. In some embodiments, a non-transitory computer-readable storage medium may store instructions that, when executed by at least one processor associated with the computer-assisted apparatus, cause the at least one processor to perform the method.

[0005] It should be understood that the above concepts and the additional concepts discussed below can be arranged in any suitable combination, as the present disclosure is not limited in this regard. In addition, other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component may be labeled in every drawing. In the drawings:

[0007] Figure 1 is an illustration of a computer-assisted system according to some embodiments; Figure 2 is a block diagram of a computer-assisted system according to some embodiments; Figure 3 is a diagram of a control loop for a computer-aided system according to some embodiments; Figure 4 is a simplified illustration of a computer-assisted system during operation according to some embodiments; Figure 5 is a simplified illustration of an input device for a computer-assisted system according to some embodiments; Figure 6 is a simplified illustration of a computer-assisted system during operation according to some embodiments; Figure 7 a graph depicting experimental results of a computer-assisted system according to some exemplary embodiments described herein; and Figure 8 A flow chart of a method of operating a computer-assisted system according to some embodiments is depicted. DETAILED DESCRIPTION

[0008] Some computer-assisted systems include follower devices that are remotely operated in response to user input received at an input device. In the case of performing such remote operation using an input device coupled to an actuator system, the actuator system can be driven to provide tactile feedback through the input device based on forces determined to be experienced by some portion of the follower device or a component supported by the follower device. Controlling such an actuator system to provide such tactile feedback may be difficult or may result in adverse or inaccurate tactile feedback to a user of the computer-assisted system. For example, in a computer-assisted system in which an input device is employed to remotely operate a manipulator arm, phase loss may be introduced between the input device and the manipulator arm due to the physical separation of the input device from the manipulator arm and the associated time delay in transmitting information. In some cases in which a computer-assisted system is used to facilitate remote operation of a manipulator arm, the phase loss may be significant and tends to produce instability in the control of the input device and / or the actuator of the manipulator arm. As another example, instability in the control of an actuator system for providing user feedback through an input device based on the interaction experienced by a follower manipulator arm of a computer-assisted system may also be caused by changes in the operating environment for the manipulator arm. For example, the manipulator arm can support an instrument that, in some operating environments and situations, can engage with materials (such as objects) of different rigidity or compliance. For example, the instrument can interact with one or more harder or more rigid object surfaces and one or more softer (e.g., lower hardness) or more compliant (e.g., lower rigidity) object surfaces. As another example, the instrument can interact with harder or more rigid object blocks / volumes in the environment and softer (e.g., lower hardness) or more compliant (e.g., lower rigidity) object blocks / volumes. As yet another example, the instrument can interact with non-solid materials in the environment, such as liquid or gel-type materials (e.g., blocks / volumes). As used herein, the hardness of an object can refer to the resistance of the object to surface deformation, and rigidity can be a measure of the resistance of an object or other material to volume deformation. As the instrument interacts with these various surfaces, volumes, or non-solid materials, changes in environmental stiffness or compliance encountered may also introduce instabilities in controlling the actuators of the input device to provide feedback to the user due to rapid increases in forces at the instrument.

[0009] The techniques described in the present disclosure can provide various benefits in a computer-assisted system including an input device and a manipulator arm controlled by the input device, wherein interaction of the manipulator arm (or a component supported by the manipulator arm, such as an instrument) is used to provide tactile feedback to a user of the input device. Example benefits include helping to maintain stability of control feedback provided by the input device, helping to improve or maintain tracking accuracy between commands received at the input device and movements performed by the manipulator arm. In some embodiments, the disclosed techniques reduce the amount of damping applied to the input device and apply little or no damping (e.g., barely detectable or undetectable based on human senses) when the manipulator arm remotely operated by the input device is not experiencing reaction forces from the operating environment (e.g., the manipulator arm or the instrument supported by the manipulator arm is not in contact with any material other than air or other gases, or is in free space).

[0010] In some embodiments, the disclosed technology provides a controller configured to compensate for the impedance of the operating environment encountered by a teleoperated manipulator arm, reducing the likelihood of a substantial increase in control loop gain, which reduces the likelihood of presenting unstable force feedback at the input device. One potential benefit includes an adaptive controller for a computer-assisted system that enhances stable force feedback for an input device by applying different damping to the feedback provided by the input device when the manipulator arm is experiencing higher environmental stiffness (e.g., contact with a more rigid object or a harder surface of an object, etc.) than when the manipulator arm is experiencing lower environmental stiffness (e.g., in free space, contact with a softer material, etc.). For example, if not compensated, contact with a substantially rigid surface (e.g., bone or another instrument in a surgical example) or a substantially rigid block or some other relatively rigid material (e.g., a more viscous fluid, a harder gel, etc.) may result in a rapid increase in control loop gain due to a rapid increase in input force measured at the instrument for a given amount of motion. As another example, the device can interact with harder, more rigid blocks of objects in the environment as well as softer (e.g., less hard), more compliant (e.g., less rigid) blocks of objects. As yet another example, the device can interact with non-solid materials in the environment, such as liquid or gel-type materials. As used herein, the hardness of an object can refer to the resistance of the object to surface deformation, and rigidity can be a measure of the resistance of an object or other material to volumetric deformation. When the device interacts with these different surfaces, blocks, or non-solid materials, the changes in the rigidity or compliance of the environment encountered may also introduce instability when the actuator of the control input device provides feedback to the user due to rapid changes in force at the device for small movements.

[0011] In some embodiments, the disclosed technology provides a controller configured to compensate for changes in the structural stiffness of a kinematic chain that includes a teleoperated manipulator arm. For example, an extended manipulator arm can be more compliant and less stiff than a folded or retracted manipulator arm. If not compensated for, compensating for the increased compliance and reduced stiffness may also result in an increase in the control loop gain. Due to its physical configuration, an extended manipulator arm will typically have a different bending stiffness than a folded or retracted manipulator arm, so that a force applied at the tip of the extended manipulator arm (compared to a folded or retracted manipulator arm) is more likely to cause the manipulator arm to flex due to the increased lever arm.

[0012] In some embodiments, the disclosed techniques allow for the use of lower mass input devices. Moreover, in some embodiments, lower mass input devices may be associated with increased control loop gain, which may make the input device more susceptible to instability. The techniques described herein may also be applied to a controller configured to compensate for an increase in feedback control loop gain for an input device feedback force caused by one or more sources.

[0013] In some embodiments, a computer-assisted system may employ a method in which a power metric indicating the amount of power of a physical interaction between a manipulator arm and its corresponding environment is determined. Similarly, a power metric based on a feedback force applied to an input device may be determined. Based on the determined power metric for the input device and the manipulator arm, the damping of the input device may be determined and applied to the input device. In this manner, the damping of the input device may be automatically adjusted based on the feedback force applied to the input device and the physical interaction between the manipulator arm and its environment. An adaptive controller according to the exemplary embodiments described herein may be employed in any computer-assisted robotic system having any associated instrument, including industrial computer-assisted systems, medical computer-assisted systems, and other appropriate systems.

[0014] In some embodiments, a computer-assisted system includes a manipulator arm configured to support an instrument and an input device configured to accept user commands to move the instrument. The manipulator arm can be configured to support multiple instruments that can interact with one or more surfaces, blocks, or other materials. The computer-assisted system can also include an actuator system configured to apply feedback forces to the input device based on forces sensed at the manipulator arm. For example, in the case of a remotely operated computer-assisted system, the actuator system can be driven to apply forces to the input device to reflect or represent forces sensed or detected at a manipulator arm positioned away from the input device. In this way, the actuator system can be employed to provide force feedback to a user of the input device. The computer-assisted system can also include a controller configured to control the forces applied to the input device, wherein the controller includes at least one processor configured to execute programming instructions that cause the at least one processor to perform the exemplary methods described herein. At least with reference to Figure 1-Figure 2 Exemplary computer-assisted systems are discussed further.

[0015] In some embodiments, a method for controlling a computer-assisted system including a manipulator arm and an input device includes measuring or estimating power (e.g., a power metric) flowing from the environment surrounding the instrument into an instrument supported by the manipulator arm. For example, the power can be measured or estimated based on contact between the instrument and a workpiece or contact between the instrument and another instrument. Measuring or estimating the power flowing into the instrument may include measuring forces elsewhere on the instrument or manipulator arm, and measuring or determining the speed of the instrument. The method may also include measuring or estimating the power flowing into the user input device by measuring or determining the feedback force applied to the input device and measuring or determining the speed of the input device. The method may also include comparing (after optional scaling) power metrics for the manipulator arm and the input device. In some embodiments, the comparison may be a difference. Based on the comparison between the manipulator arm power metric and the input device power metric, damping for the input device is determined. In some embodiments, this determination is primarily based on whether the manipulator arm power metric exceeds the input device power metric. In the case where the manipulator arm power metric is greater (e.g., for a first range of difference values), for example, based on a strictly monotonic relationship (e.g., a positive monotonic relationship) between the damping and the difference between the manipulator arm power metric and the input device power metric, greater damping may be applied to the input device. In the event that the manipulator arm power metric is less than or equal to the input device power metric (e.g., for a second range of difference values), the damping can be set to a baseline value (e.g., zero or non-zero value). The baseline value may not be set until the input device power metric exceeds or equals the manipulator arm power metric to avoid introducing instability in the input device. In this way, the damping is driven based on the difference in the relatively scaled power metrics for the input device and the manipulator arm. Figure 8 Exemplary methods of controlling a computer-assisted system are further discussed.

[0016] According to exemplary embodiments described herein, a power metric may represent power (e.g., energy) over a time period. For example, in some embodiments, a manipulator arm power metric may indicate the energy of an apparatus interacting with an apparatus environment. Similarly, an input device power metric may indicate feedback provided by an input device in response to an apparatus interaction. The power metric may include the accumulation of power over a follower time period (e.g., a period of time). The follower time period may start at the moment when an input device is used and a feedback force is provided at a user input device, and may end until the input device is released and no feedback force is presented at the user input device. In some embodiments, the follower time period may be any length of time that a user uses an input device. In some embodiments, the follower time period may be between 1 ms and 7 hours. According to such embodiments, the power metric may represent the energy of a manipulator arm interaction and an input device interaction over a follower time period. In some embodiments, the follower time period may consist of several integrals of instantaneous power over an interval time period. That is, in some embodiments, the overall integral of the instantaneous power may be determined by the sum of multiple interval integrals over an interval time period. For example, determining the power metric may include repeatedly integrating the instantaneous power over an interval time period and summing each repeated interval integral. In some embodiments, the interval time period may be determined at least in part by the interval of a control loop or servo loop for the computer-aided system. For example, the interval time period may be between 0.0005 ms and 10 ms (corresponding to a control loop or servo loop frequency between 2000 and 100 Hz), but any suitable interval time period may be used. Other exemplary time periods are further discussed with reference to other embodiments described herein. Figure 4-Figure 6 Examples of determining a power metric are further discussed in the exemplary embodiments of the present invention.

[0017] In some embodiments, an adaptive damper is implemented for a computer-assisted system, wherein a controller for the damper is capable of discarding excessive negative energy generation over time to avoid delaying the increase in damping in the event of a change in the environmental interaction of the manipulator arm. For example, if an excessive amount of negative net energy is generated, damping may be set to zero or approximately zero once the net energy reaches zero or is negative, and damping may be maintained at zero or approximately zero until the net energy generated becomes positive again, which may take a significant amount of time. By discarding negative energy in some embodiments, the time to increase damping above or near zero may be reduced (e.g., damping may recover faster than a control scheme that does not discard excess negative energy). In some embodiments, a computer-assisted system rapidly increases damping applied to an input device (e.g., faster than an embodiment that does not discard excessive negative energy) in response to a change in a power metric of a manipulator arm that may move into contact with a surface (e.g., a substantially rigid surface), a block, or other material (resulting in a rapid increase in the power metric), thereby resulting in a rapid increase in the power metric. As previously described, in some embodiments, determining the damping applied to the input device may be based on a comparison (e.g., a difference) between scaled power metrics for the input device and the manipulator arm. In the event that the scaled power metric of the input device exceeds the scaled power metric of the manipulator arm (e.g., in the event that the net power metric is negative), the damping of the input device can be set to a baseline minimum value. In some embodiments, the baseline minimum value can be zero. In other embodiments, the baseline minimum value can be non-zero. In some embodiments, the method of controlling a computer-assisted system includes attenuating the excess input device power metric toward a net power metric of zero over time. That is, the method can include reducing the accumulation of power metrics of instrument interactions over time, and can also include reducing the accumulation of power metrics of input device interactions over time. For example, in some embodiments, a constant linear slew rate can be used to reduce the input device power metric until it equals the manipulator arm power metric. As another example, an exponential decay can be used to reduce the net power metric. Any suitable profile can be used to reduce the input device power metric over time, as the present disclosure is not limited thereto. In this way, when the manipulator arm power metric increases rapidly, damping can be applied to the input device without the delay introduced by the excess input device power metric.

[0018] In addition to the above, in some embodiments, a damping limit is used to constrain the amount of damping applied to the input device. Applying higher damping to the input device can provide more stable force feedback control on the input device; however, applying higher damping may reduce the user-perceived quality of feedback or responsiveness of the computer-assisted system. For example, in some applications of computer-assisted systems according to exemplary embodiments described herein (e.g., robotic surgery), the movement of the input device may be undesirable when the input device resists the movement or is slow relative to an input device without damping. Therefore, in some cases, the damping limit is increased at a limited rate of change, thereby reducing the possibility of a large increase in damping applied to the input device in a short time span. The "short" time span may be based on the force, damping, and cycle time associated with the expected use of the computer-assisted system, and may therefore vary from system to system. In some embodiments, a "short" time span may include an instantaneous increase (e.g., a step function). In some embodiments, a method of controlling a computer-assisted system may include limiting the amount of damping applied to the input device to the damping limit. In some embodiments, the method may include, in response to determining that the amount of damping is greater than a damping threshold, increasing the damping limit at a known rate. In some embodiments, the damping threshold can be equal to the damping limit, and the damping threshold can also be variable based on the damping limit. For example, if the damping limit increases, the damping threshold can also increase accordingly. In this way, in some embodiments, the damping limit can only increase when the amount of damping continues to exceed the increased damping limit. The rate can be a monotonic rate (e.g., a positive monotonic rate), a linear rate, an exponential rate, or any other suitable rate profile. In some embodiments, the damping limit can be increased to no more than a maximum damping limit, which can be predetermined based on the specific kinematics of the input device. For example, for a range of differences between the instrument power metric and the input device power metric, the damping can be disproportional to the difference because the damping is limited by the damping limit. In some embodiments, in response to the amount of damping being less than the damping limit, the damping limit can be reduced. For example, in some embodiments, the damping limit can decrease monotonically, linearly, or at an exponential rate. In some embodiments, the damping limit may not decrease until a threshold time period has passed. This arrangement can ensure that the damping limit remains high in the event that the amount of damping applied to the input device is momentarily reduced. Reference Figure 7Exemplary embodiments of damping limits and thresholds are further discussed. According to exemplary embodiments described herein, methods may be described without specific reference to directionality. In some embodiments, power metrics and damping may be directional or assigned directionality. For example, power metrics and damping may be associated with three non-parallel translational degrees of freedom (e.g., x, y, and z directions). In such embodiments, power metrics and damping may be determined in each degree of freedom. In some embodiments, damping and power metrics may be determined in rotational degrees of freedom (e.g., pitch, roll, and yaw directions). In some embodiments, power metrics and damping may be determined in any number of translational and rotational degrees of freedom or any subcombination of rotational and translational degrees of freedom. In some embodiments, the power metric may be a scalar that is assigned directionality for applying directional damping. Reference Figure 6 Examples of assigning directionality to power metrics are further discussed.

[0019] According to exemplary embodiments described herein, "damping" is a force that is opposite to the speed of the input device. Damping can be a resistance that is proportional to the speed of the input device. Therefore, an increase in the speed of the input device can result in a corresponding increase in the damping force applied opposite to the speed of the input device. According to exemplary embodiments described herein, a method of controlling a computer-assisted system includes applying damping to the input device with a damping system. Damping can be applied via an active force or a passive force. For example, in some embodiments, an actuator of an actuator system can be driven to apply an active damping force in the form of damping in the direction of motion of the input device or in the opposite direction. Such a damping force can be incorporated into the overall force output of the actuator system. As another example, in some embodiments, the damping system can include an adjustable physical damper (e.g., a braking system) that can apply a damping force to the input device. As yet another example, the physical damper can be physically adjusted to change the damping rate of the physical damper. Therefore, determining the amount of damping and applying it to such an input device can include adjusting the physical damper to achieve a desired amount of damping. Any combination of physical dampers and actuators operating as dampers may be used as part of the damping system, as the present disclosure is not limited in this regard. While in some embodiments herein, damping is proportional to velocity (e.g., linear), in other embodiments, damping may be nonlinear, piecewise linear, etc.

[0020] According to exemplary embodiments described herein, power metrics of the manipulator arm and the input device can be used to determine the damping to be applied to the input device. In some cases, the manipulator arm and the input device can be scaled with different scalings, so that when directly compared, the power metric of one of them may be much greater than the power metric of the other. For example, the manipulator arm can move a distance of the order of 1m, while the input device can move a distance of the order of 10cm. Therefore, when directly compared, the manipulator arm power metric may be an order of magnitude larger than the input device power metric. Therefore, in some embodiments, the power metrics of the manipulator arm and the input device can be determined by appropriate scaling so that they can be appropriately compared. In some embodiments, this scaling can be based on a scaling factor of the position tracking between the input device and the manipulator arm, or a scaling factor based on the force experienced by each side of the telerobot. Any suitable scaling factor for the power metric can be used, as the present disclosure is not limited thereto. In the exemplary embodiments described herein, power metrics of manipulator arms and input devices are generally described such that an increase in the power metric corresponds to an increase in the amount of power or energy, a decrease in the power metric corresponds to a decrease in the amount of power or energy, and a larger power metric corresponds to a larger amount of power or energy than a lower or smaller power metric. It will be appreciated that mathematical manipulations that merely change the numerical value of the power metric do not change the amount of potential power associated with the numerical value. For example, in a system in which a mathematical manipulation or calculation associates a lower or smaller (including negative or more negative) numerical value with a power metric corresponding to a larger amount of power or energy, a lower or smaller numerical value corresponds to a larger power metric.

[0021] According to exemplary embodiments described herein, a method of controlling a computer-aided system includes determining and applying damping as part of a control loop. In some embodiments, the control loop may operate at a frequency suitable for attenuating vibrations in a target frequency band. The method according to embodiments described herein may be used to attenuate vibrations of an input device less than or equal to 10 Hz. Accordingly, the control loop may operate at a frequency greater than 100 Hz to 1000 Hz. In some embodiments, the control loop may operate at a frequency range greater than ten times the upper limit of the target frequency range. In some embodiments, the speed of the control loop may determine an accumulation time period for power metrics determined during a control loop cycle. In some embodiments, the power metric may be accumulated (e.g., integrated) over a time period that may be decomposed into a sum of multiple interval time periods (e.g., where the interval time period is associated with a control loop cycle time or a servo cycle time). Depending on the particular computer-aided application, the control loop may operate at any other frequency, as the present disclosure is not limited in this regard.

[0022] The present disclosure describes various devices, elements and parts of computer-aided devices and elements in three-dimensional space. As used herein, the term "position" refers to the site of an element or a part of an element. The orientation can be determined in any number of dimensions suitable for the system, such as in one-dimensional, two-dimensional space or three-dimensional space (for example, along the three translational degrees of freedom of Cartesian x, y and z coordinates). As used herein, the term "orientation" refers to the rotational placement of an element or a part of an element. Orientation can be determined in any number of dimensions suitable for the system, such as in one, two, three degrees of freedom (for example, in three rotational degrees of freedom, such as roll, pitch and yaw, which can be represented by angle-axis, rotation matrix, quaternion and / or the like). As used herein, and for devices with repositionable arms and / or other repositionable structures, the term "near / proximal" refers to the direction of the base of the computer-aided device along the kinematic chain of the computer-aided device, and "far / distal" refers to the direction away from the base along the kinematic chain.

[0023] As used herein, the term "pose" refers to the multi-degree-of-freedom (DOF) spatial position and orientation of the coordinate system of interest attached to a rigid body. In general, a pose includes pose variables for each DOF in the pose. For example, a full 6-DOF pose for a rigid body in three-dimensional space will include 6 pose variables corresponding to 3 position DOFs (e.g., x, y, and z) and 3 orientation DOFs (e.g., roll, pitch, and yaw). At the same time, a 3-DOF position pose for a rigid body will only include pose variables for 3 position DOFs. Moreover, a 3-DOF orientation pose for a rigid body will only include pose variables for 3 rotational DOFs. In addition, the velocity of the pose captures the change of the pose over time (e.g., the first-order derivative of the pose). For a full 6-DOF pose for a rigid body, the velocity will include 3 translational velocities and 3 rotational velocities (e.g., both angular velocity and translational velocity). A pose with other numbers of DOFs will have a corresponding number of velocities, translational and / or rotational velocities. Other examples for rigid bodies include two translational and one rotational DOF, two or three translational DOF, two or three rotational DOF.

[0024] Aspects of the present disclosure are described with reference to computer-assisted systems and devices, which may include systems and devices that are remotely operated, remotely controlled, autonomous, semi-autonomous, robotic, and / or the like. In addition, aspects of the present disclosure are described in terms of embodiments using surgical systems. However, those skilled in the art will appreciate that the inventive aspects disclosed herein may be embodied and implemented in various ways, including robotic and (if applicable) non-robotic embodiments and implementations. The implementations on surgical systems are merely exemplary and should not be considered to limit the scope of the inventive aspects disclosed herein. For example, the techniques described with reference to surgical instruments and surgical methods may be used in other contexts. Thus, the instruments, systems, and methods described herein may be used for humans, animals, parts of human or animal anatomy, industrial systems, general robots, or teleoperated systems. As a further example, the instruments, systems, and methods described herein may be used for non-medical purposes, including industrial uses, general robotic uses, sensing or manipulating non-tissue artifacts, cosmetic improvements, imaging of human or animal anatomy, collecting data from human or animal anatomy, setting up or removing systems, training medical or non-medical personnel, and / or the like. Additional example applications include procedures performed on tissue removed from a human or animal anatomy (not returned to the human or animal anatomy), and procedures performed on human or animal cadavers. In addition, these techniques may also be used for medical treatment or diagnostic procedures that may or may not include surgical aspects.

[0025] It should also be noted that although some embodiments described herein use a rigid linkage mechanism, the present disclosure is not limited thereto. The techniques and methods described herein can be applied to flexible robotic systems. For example, the methods described herein can be applied to rigid linkage robotic systems, flexible catheter systems, or other flexible robotic systems.

[0026] Turning to the drawings, specific non-limiting embodiments are described in more detail. It should be understood that the various systems, components, features, and methods described with respect to these embodiments may be used individually and / or in any desired combination, as the present disclosure is not limited to only the specific embodiments described herein.

[0027] Figure 1 1 is a simplified diagram of an example computer-assisted system according to various embodiments. In some examples, the computer-assisted system is a teleoperation system 100. In a medical example, the teleoperation system 100 may be a teleoperated medical system, such as a surgical system. As shown, the teleoperation system 100 includes a follower device 104 that may be remotely operated by being controlled by one or more leader input devices 106, which are configured to accept external inputs, as described in more detail below. A system including a leader device and a follower device is referred to as a leader-follower system. Figure 1As shown, the input device is part of an input system that includes a workstation 102 (eg, a console). In other embodiments, the input system may be of any suitable form and may or may not include a workstation 102.

[0028] exist Figure 1 In an exemplary embodiment of the present invention, the workstation 102 includes one or more input devices 106 configured to be contacted and manipulated by a user 108. For example, the workstation 102 may include one or more input devices 106 configured to be used by a hand, head, or some other body part of the user 108. The input device 106 in this example is supported by the workstation 102 and may be mechanically grounded. In some embodiments, an ergonomic support 110 (e.g., a forearm rest) may be provided on which the user 108 may rest his or her forearm. In some examples, the user 108 may perform tasks at the work site during a procedure by commanding the follower device 104 using the input device 106. In some embodiments, the workstation 102 may be physically located near the follower device 104. In other embodiments, the workstation 102 may be remote from the follower device 104 and may communicate with the follower device via a local area network, a wide area network, and / or via the Internet via one or more communication protocols.

[0029] like Figure 1 As shown, the workstation 102 includes a display unit 112. The display unit 112 can display images for viewing by the user 108. In some embodiments, the display unit 112 can be moved with various degrees of freedom to accommodate the viewing position of the user 108 and / or optionally provide control functions as another input device. In an example of a remote operation system 100, the displayed image can depict a work site where the user 108 performs various tasks by manipulating the input device 106 and / or the display unit 112. In some examples, the workstation 102 can receive the image displayed by the display unit 112 from one or more imaging devices arranged at the work site. In other examples, the image displayed by the display unit 112 can be generated by the display unit 112 (or by a different connected device or system), such as a virtual representation of a tool, a work site, or for a user interface component.

[0030] according to Figure 1 In some embodiments, when using workstation 102, user 108 may sit in a chair or other support in front of workstation 102, position his or her eyes in front of display unit 112, manipulate input device 106, and rest his or her forearms on ergonomic support 110 as needed. In some embodiments, user 108 may stand at the workstation or assume other postures, and the position (height, depth, etc.) of display unit 112 and input device 106 may be adjusted to accommodate user 108.

[0031] In some embodiments, one or more input devices 106 may be ungrounded (an ungrounded input device has no kinematic grounding, such as an input device held by a user's 108 hand without additional physical support). Such an ungrounded input device may be used in conjunction with a display unit 112. In some embodiments, a user 108 may use a display unit 112 located near a work site so that the user 108 manually operates instruments at the work site, such as laparoscopic instruments in a surgical example, while viewing an image displayed by the display unit 112.

[0032] The teleoperation system 100 may also include a follower device 104 that can be commanded by the workstation 102. In a medical example, the follower device 104 may be located near an operating table (e.g., a table, bed, or other support) on which a patient may be positioned. In some medical examples, a working site is provided on an operating table, such as on or in a patient, a simulated patient, or a model, etc. (not shown). The follower device 104 shown includes a plurality of manipulator arms 120, each manipulator arm 120 being configured to be coupled to an instrument assembly 122. The instrument assembly 122 may include, for example, an instrument 126. In various embodiments, one or more of the instruments 126 may include an imaging device (e.g., an optical camera, a hyperspectral camera, an ultrasound sensor, etc.) for capturing images. For example, one or more of the instruments 126 may be an endoscope assembly that includes an imaging device that may provide a captured image of a portion of the working site to be displayed via the display unit 112. The one or more instruments 126 may also include instruments configured to function in an operating environment and physically interact with physical objects or features of the operating environment (e.g., in a medical example, the operating environment may be a workspace inside or outside a patient's body). Examples of potential instruments 126 may include, but are not limited to, graspers, scalpels, staplers, imagers or other sensors, cautery instruments, suction irrigators, and scissors. Any suitable instrument may be used with the manipulator arm 120, as the present disclosure is not limited in this regard.

[0033] In some embodiments, the manipulator arm 120 and / or the instrument assembly 122 can be controlled to move and articulate the instrument 126 / articulate the instrument in response to the user 108's manipulation of the input device 106, and in this way "follow" the input device 106 through remote operation. This enables the user 108 to use the manipulator arm 120 and / or the instrument assembly 122 to perform tasks at the work site. The manipulator arm 120 and the follower device 104 are examples of repositionable structures on which instruments (such as manipulation instruments and / or imaging instruments including imaging instruments) can be mounted. The repositionable structure (s) of the computer-assisted system include a repositionable structure system of the computer-assisted system. For the surgical example, the user 108 can guide the follower manipulator arm 120 to move the instrument 126 to perform a surgical procedure at an internal surgical site through a minimally invasive orifice or a natural orifice. The manipulator arm 120 and / or the instrument assembly 122 can also provide feedback information presented to the user 108 through one or more input devices 106. For example, in some embodiments, the manipulator arm 120 and / or the instrument assembly 122 may provide force information that is used to apply feedback forces at one or more input devices 106 .

[0034] As shown, the control system 140 is provided external to the workstation 102 and communicates with the workstation 102. In other embodiments, the control system 140 may be provided in the workstation 102 or in the follower device 104. When the user 108 moves the input device(s) 106, sensed spatial information including sensed position and / or orientation information based on the movement of the input device 106 is provided to the control system 140. The control system 140 may determine control signals or provide control signals to the follower device 104 based on the received information and the user input to control the movement of the manipulator arm 120, the instrument assembly 122, and / or the instrument 126. In one embodiment, the control system 140 supports one or more wired communication protocols (e.g., Ethernet, USB, and / or the like) and / or one or more wireless communication protocols (e.g., Bluetooth, IrDA (Infrared Data Communication), HomeRF (Home Radio Frequency), IEEE 1002.11, DECT (Digital Enhanced Cordless Communication), wireless telemetry, and / or the like). In some embodiments, control system 140 may be configured to implement the example methods described herein and determine feedback forces to be applied to one or more input devices 106 .

[0035] The control system 140 may be implemented on one or more computing systems. The one or more computing systems may be used to control the follower device 104. Additionally, the one or more computing systems may be used to control the movement of components of the workstation 102, such as the display unit 112.

[0036] As shown, the control system 140 includes a processor 150 and a memory 160 storing a control module 170. In some embodiments, the control system 140 may include one or more processors, non-persistent storage devices (e.g., volatile memory, such as random access memory (RAM), cache memory), persistent storage devices (e.g., hard disk, optical drive (such as compact disk (CD) drive or digital versatile disk (DVD) drive), flash memory, etc.), communication interfaces (e.g., Bluetooth interface, infrared interface, network interface, optical interface, etc.), and many other elements and functions. In addition, the functions of the control module 170 can be implemented in any technically feasible software and / or hardware.

[0037] Each of the one or more processors of the control system 140 may be an integrated circuit for processing instructions. For example, the one or more processors may be one or more cores or micro-cores of a processor, a central processing unit (CPU), a microprocessor, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a digital signal processor (DSP), a graphics processing unit (GPU), a tensor processing unit (TPU), and / or the like. The control system 140 may also include one or more input devices, such as a touch screen, a keyboard, a mouse, a microphone, a touchpad, an electronic pen, or any other type of input device.

[0038] The communication interface of the control system 140 may include an integrated circuit for connecting the computing system 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 any other type of network) and / or another device, such as another computing system.

[0039] In addition, the control system 140 may include one or more output devices, such as a display device (e.g., a liquid crystal display (LCD), a plasma display, a touch screen, an organic LED display (OLED), a projector, or other display device), a printer, a speaker, an external storage device, or any other 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 input and output device(s) described above may take other forms.

[0040] In some embodiments, the control system 140 can be connected to a network or as part of a network. The network may include multiple nodes. The control system 140 can be implemented on a node or a group of nodes. By way of example, the control system 140 can be implemented on a node of a distributed system connected to other nodes. By way of another example, the control system 140 can be implemented on a distributed computing system with multiple nodes, wherein different functions and / or components of the control system 140 can be located on different nodes within the distributed computing system. In addition, one or more elements of the above-mentioned control system 140 can be located at a remote site and connected to other elements via a network.

[0041] The software instructions in the form of computer-readable program code for executing the embodiments of the present 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, disk, tape, flash memory, physical memory, or any other computer-readable storage medium. Specifically, the software instructions may correspond to a computer-readable program code that, when executed by (one or more) processors (e.g., processor 150), is configured to perform an embodiment of any method described herein.

[0042] Figure 2 is a block diagram of a computer-assisted system according to some embodiments. Figure 2 As shown, the computer-assisted system includes an input device 200. The input device can be configured to receive external input from a user. For example, the input device provides a user interface through which the user can transmit physical motions and forces to the user interface, which are reflected in the following manipulator arm. That is, the manipulator arm can move based on a predetermined scaling factor according to the input received at the input device. Figure 2 As shown, the input device includes (one or more) actuators 204. The (one or more) actuators 204 can be configured to apply a force to the input device to provide feedback to a user of the input device. For example, the (one or more) actuators can be configured to apply a force based on a force sensed at the manipulator arm 250. The (one or more) actuators can include one or more motors, servos, stepper motors, brushless motors, pneumatic actuators, or any other suitable actuators. The actuator can be part of an actuator system that includes the (one or more) actuators and / or one or more other actuators. Therefore, although the (one or more) actuators are in Figure 2 is shown as part of an input device, but in other embodiments, the actuator may be provided as a separate actuator system. Figure 2As shown, the input device may optionally include (one or more) dampers 206. The damper may be an adjustable damper so that the amount of damping applied to the input device is controlled by (one or more) processors (e.g., 302) according to the methods described herein. In some embodiments, the damper may include a brake that, when engaged, may apply a constant or variable braking force to the input device. In some embodiments, (one or more) actuators 204 may be used as dampers (e.g., by applying resistance opposite to the movement of the input device), in which case a physical damper may not be employed. According to exemplary embodiments herein, (one or more) actuators and (one or more) dampers may constitute part of a damping system that may include components of the input device and other components. The damping system may be configured to apply a damping force to the input device. Some components of the damping system (e.g., actuators) may be used as part of both a feedback system and a damping system (e.g., the force output of the actuator may include both a damping force and a feedback force).

[0043] like Figure 2 As shown, the input device 200 also includes optional (one or more) sensors 208. The sensors may include accelerometers, inertial measurement units, contact sensors, force sensors, rotary encoders, potentiometers, position sensors, speed sensors, or other desired sensors, which are configured to provide information about the input device and its environment to (one or more) processors (e.g., 302). In some embodiments, (one or more) actuators 204 may provide (one or more) processors with information about the force applied to the input device and the position of the input device. For example, force can be measured by converting motor torque and / or current into force. As another example, position can be measured by monitoring the number of steps of a stepper motor or otherwise monitoring the speed of the motor over time. According to such examples, no additional sensors may be used in the input device. In some embodiments, the input device may include one (or more) processors (not shown). (One or more) processors may be configured to execute programming instructions that may allow the input device to communicate, sense user input, and provide feedback to the user based on the output at the manipulator arm 250.

[0044] according to Figure 2In an embodiment of the present invention, the manipulator arm 250 is configured to cooperate with the input device 200. For example, the manipulator arm 250 can be configured to follow user input at the input device 200. As with the input device 200, the manipulator arm includes (one or more) actuators 254. The (one or more) actuators 254 can be configured to apply force to the manipulator arm to move the manipulator arm and apply force to the instrument environment. In addition, the (one or more) actuators can be used to operate one or more instruments associated with the manipulator arm 250. The (one or more) actuators can be configured to move the manipulator arm based on movement of the input device 200. The (one or more) actuators 254 can include one or more motors, servos, stepper motors, brushless motors, pneumatic actuators, or any other suitable actuators. As shown in FIG. Figure 2 As shown, the manipulator arm may optionally include one or more instruments 256. One or more instruments may be coupled to the manipulator arm and may be removable and interchangeable in some embodiments. The instrument(s) 256 may include one or more of an imaging device, a grasper, a scalpel, a stapler, a knife, a cautery instrument, and scissors.

[0045] like Figure 2As shown, the manipulator arm 250 also includes optional (one or more) sensors 258. The sensors may include accelerometers, inertial measurement units, contact sensors, force sensors, rotary encoders, potentiometers, position sensors, speed sensors, or other desired sensors that are configured to provide information about the manipulator arm and its environment to (one or more) processors (e.g., 302). In some embodiments, (one or more) sensors may be configured to provide (one or more) processors (e.g., 302) with information about contact forces on the manipulator arm, the position of the manipulator arm, and the speed of the manipulator arm. In some embodiments, (one or more) actuators 254 may provide (one or more) processors (e.g., 302) with information about the force applied to the manipulator arm and the position of the manipulator arm. For example, force may be measured by converting motor torque and / or current into force. As another example, position / and speed may be measured by monitoring the number of steps of a stepper motor or otherwise monitoring the speed of the motor over time. In some embodiments, (one or more) sensors 258 may include a force sensor located at a distal portion of the instrument. In some embodiments, the distal portion of the instrument includes an end effector of the instrument. The end effector is configured to interact with the environment, such as manipulating the environment and / or sensing data from the environment. Examples of end effectors include end effectors with manipulating components, such as fingers, suction devices, irrigators, cutters. Examples of end effectors also include end effectors with sensor components, such as optical imaging devices, temperature or force sensors, and ultrasonic probes. In some embodiments, (one or more) sensors 258 may include one or more strain gauges positioned on a portion of the manipulator arm. The manipulator arm 250 may include any suitable number and type of sensors, as the present disclosure is not limited thereto. In some embodiments, the manipulator arm may include one (or more) processors (not shown). The (one or more) processors may be configured to execute programming instructions that may allow the manipulator arm to communicate, sense its environment, and interact with its environment based on input at the input device 200.

[0046] according to Figure 2In some embodiments shown, the computer-assisted system includes a control system 300 that can coordinate and control the interoperation between the input device 200 and the manipulator arm 250. The control system 300 can implement a method for controlling the operation of the input device 200 and the manipulator arm 250 according to the exemplary embodiments described herein. In particular, the control system receives input from the input device 200 and can provide feedback from the manipulator arm 250 to the input device. The control system also sends commands to the manipulator arm 250 based on the input received at the input device 200 and receives sensor feedback from the manipulator arm. System 300. The control system 300 can control the output of (one or more) actuators of both the manipulator arm 250 and the input device 200 in one or more control loops. In some embodiments, the control system 300 can cooperate with (one or more) processors of the input device and the manipulator arm to control the input device and the manipulator arm.

[0047] like Figure 2 As shown, the control system includes one or more processors 302, which are configured to execute programming instructions, which cause one or more processors to perform the exemplary methods described herein. The programming instructions can be stored on a memory 304, which can be a non-transient memory. In some embodiments, the control system 300 can include any (one or more) processors of the input device and / or any processor of the manipulator arm, or communicate with it to control the input device and the manipulator arm. In some embodiments, the control system can be physically implemented in an electronic circuit (e.g., an integrated circuit). In other embodiments, the control system can be physically implemented in multiple electronic circuits (e.g., multiple integrated circuits), which are physically co-located or distributed relative to each other. In some embodiments, the processor of the control system can be physically set in or on the input device, the manipulator arm, the auxiliary tower or the user console, another part of the computer-assisted system, or any combination thereof. In the example described herein, the control system 300 also includes a communication interface 306, which can facilitate the communication of commands, requests, and information between the manipulator arm, the input device, and the control system 300. The communication interface 306 may include circuitry for connecting the control system 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 any other type of network) and / or to another device (such as another control system). In some embodiments, the manipulator arm 250 and the input device 200 may also include a communication interface to facilitate communication with the control system 300.

[0048] Figure 3 is a diagram of a control loop for a computer-aided system according to some embodiments. Figure 3As shown, the input of the control loop is the force from the user. The force from the user can be applied to the input device and can be monitored by one or more processors of the input device. That is, one or more processors of the input device can receive information from one or more sensors and / or actuators of the input device, which can be used to determine the force input from the user. In box 400, the overall motion and force of the input device are represented. The motion and force are the result of the combination of the force input by the user and the feedback from the control loop. In box 402, the position movement and / or force of the input device are scaled. The scaling can be based on the kinematic differences between the input device and the manipulator arm. For example, the range of motion of the input device can be much smaller than the range of motion of the manipulator arm, so that the motion and force of the input device are scaled to match the larger range of motion of the manipulator arm. In some embodiments, when information is transferred from the physical input device to the physical manipulator arm, the scaled motion and force are used to command the virtual manipulator arm. Such a step can use inverse kinematics to provide the position or motion of the command to the virtual or actual manipulator arm. Alternatively, such a step may not use inverse kinematics. For example, some systems utilize a user input device to command a manipulator arm having similar or identical kinematics to the input device, and such systems may command the joint position or motion of the manipulator arm directly based on the joint position or motion of the input device without employing inverse kinematics. In block 406, a filter may be employed to reduce noise or adjust phase. Any suitable filter may be employed, as the present disclosure is not limited in this regard. In block 408, the manipulator arm is controlled based on the filtered signal provided by the virtual manipulator arm. That is, the manipulator arm moves proportionally based on the movement at the input device in block 400.

[0049] like Figure 3 As shown, the manipulator arm of box 408 provides a feedback signal. The feedback signal can be based on a force measured at the manipulator arm, which can be presented to an input device so that a user feels feedback in response to the force experienced by the manipulator arm. In particular, in box 410, the manipulator arm can interact with its environment. As a result of this interaction, one or more sensors on the manipulator arm can be used to measure the force. In box 412, the force signal can be filtered to reduce noise or a target-specific frequency response range. The force feedback filter of box 412 can include determining damping and applying it to the input device to avoid instability in the input device. Therefore, box 412 can represent an exemplary method described herein. In other embodiments, a separate branch of the loop can extend from box 400, which can provide a damping input to the input device output. For example, an additional loop can apply a force based on the determined damping and the speed of the input device. In box 414, a force feedback gain can be applied to the filtered force feedback signal to change the amount of feedback force presented to the user at the input device. As shown Figure 3As shown, the force feedback is then returned to the input device for presentation, thereby forming a closed control loop. As will be discussed further below, Figure 3 The control loop shown may include determining damping and applying it to the input device.

[0050] Figure 4 is a simplified illustration of a computer-assisted system during operation, illustrating a method of controlling the computer-assisted system, according to some embodiments. Figure 4 As shown, the computer-assisted system includes an input device 106 and a manipulator arm 120. The manipulator arm includes an instrument 126 having a distal portion 107 (e.g., an end effector, etc.) that physically interacts with the environment 500. Depending on the specific application, the environment may include different objects with different mechanical properties (e.g., tables, work surfaces, parts, floors, walls, ceilings) and / or different objects with different non-solid materials (e.g., gels, liquids, gases). Examples of objects include subjects (e.g., patients, parts of patient anatomy, industrial workpieces, training equipment). As previously described, the input device 106 and the manipulator arm 120 can be remotely located from each other and can communicate via a control system configured to coordinate the operation of the input device and the manipulator arm. The manipulator arm can be configured to proportionally follow the movement and force applied by the user to the input device. That is, the user input received at the input device can be the basis for the command sent to the manipulator arm to move and interact with the environment 500.

[0051] according to Figure 4 Embodiments of the present invention are provided for determining parameters for a damping level for an input device. In particular, according to Figure 4 In an embodiment of the present invention, the damping of the input device 106 is determined based on a power metric associated with the input device and the manipulator arm 120. Figure 4 As shown, a power metric between the manipulator arm and the environment can be determined as P_env. The power can be calculated by determining the force and velocity of the portion of the manipulator arm that is engaged with the environment 500. For example, the power metric can be calculated as the force at the distal portion 107 multiplied by the velocity of the distal portion. In some embodiments, the power metric can be determined by the product of the rotational velocity and the applied torque. In some embodiments, the power metric can be determined by the product of the translational velocity and the translational force, such as Figure 4 As shown. Figure 4As shown, the power metric of the input device can be determined as a combination of the power of the force feedback P_ffb and the power of the damper P_Damper. In some embodiments, these power metrics can be determined based on the velocity of the input device 106 multiplied by the force applied to the input device by one or more actuators. Based on the combination of these power metrics, the damping of the input device 106 can be determined. In particular, in some embodiments, the excess power can be determined based on a comparison of the power metrics according to the following equation:

[0052] Where α is a scaling factor. In some embodiments, if P_excess is less than or equal to 0, the damping of the input device may be set to zero. In some embodiments, if P_excess is greater than 0, the damping may be set based on the following equation:

[0053] Where K is a gain factor, which can be set depending on the specific kinematics of the computer-assisted system. In some embodiments as described above, the accumulation of power metrics can be used to determine the damping of the input device. For example, the excess energy E_excess can be determined by taking the integral of P_excess over a specific time period. In such embodiments, the energy can be used to set the damping factor in the case where the energy is greater than zero according to the following equation:

[0054] where K is a gain factor which can be set depending on the specific kinematics of the computer-assisted system.Thus, the damping for the input device can be determined and applied to the input device based on the power measurements at the input device and the manipulator arm.

[0055] Figure 5 is a simplified illustration of an input device 106 of a computer-assisted system according to some embodiments. Figure 5 As shown, the input device 106 includes a virtual damper 103. According to some embodiments, the virtual damper 103 has a damping coefficient B_A.Damper, which can be obtained according to the above reference Figure 4 The process described above is determined. Figure 5 In some embodiments, the damper may be virtual in that the actuator is configured to apply an active force in a direction opposite to the direction of the velocity of the input device. In other embodiments, the damper may be a physical damper with an adjustable damping rate. Figure 5The embodiment of the present invention shows a damper in one direction, but in other embodiments, damping can be applied in multiple degrees of freedom, including translational degrees of freedom (e.g., x, y, and z Cartesian directions), rotational degrees of freedom (e.g., pitch, roll, and yaw directions), or any combination or subcombination thereof. Figure 6 Applying damping in multiple directions is further described.

[0056] Figure 6 is a simplified illustration of a computer-assisted system during operation according to some embodiments. Specifically, Figure 6 1 shows the use of directionality in determining and applying damping to the input device 106. Figure 5 The same as the example, Figure 6 The computer-assisted system of FIG. 5 includes a manipulator arm 120. The manipulator arm includes an instrument 126 having a distal portion 107 (eg, an end effector) that physically interacts with an environment 500. Depending on the specific application, the environment may include objects with different mechanical properties and / or different non-solid materials, similar to a combination of Figure 4 As described in the embodiments.

[0057] according to Figure 6 In the embodiment of FIG. 1 , two Cartesian directions are shown, representing two translational degrees of freedom of the input device 106 and the manipulator arm 120. That is, both the input device 106 and the manipulator arm 120 may be able to move in the x and y directions, such as Figure 6 As shown. In some embodiments, the reference frame of the Cartesian direction can be different between the input device 106 and the manipulator arm 120. That is, in the global reference frame, the x-direction of the input device may not be parallel to the x-direction of the manipulator arm. Instead, movement of the input device in the x-direction can be transformed into movement of the manipulator arm in the x-direction based on the local reference frame of the manipulator arm. In some embodiments, in the global reference frame, the Cartesian direction of the input device can be parallel to the Cartesian direction of the manipulator arm, as the present disclosure is not limited in this regard.

[0058] according to Figure 6In an embodiment, power metrics of the input device 106 and the manipulator arm 120 are determined in three non-parallel translational degrees of freedom (e.g., x, y, and z directions). In other embodiments, power may also be determined in one or more rotational degrees of freedom or any subset of translational and rotational degrees of freedom, as the present disclosure is not limited in this regard. As previously described, the power metric may be determined as the product of a force measurement and a velocity measurement. In some embodiments, the machine power metric may be determined by projecting the force applied to the input device onto the translational degrees of freedom (or other degrees of freedom) of the input device. In some embodiments, such projection may be achieved by taking a dot product. The projected force may then be multiplied by the input device velocity in each corresponding direction to determine an input device power metric matrix. Similarly, the machine power metric may be determined by projecting the force measured at the machine onto the translational degrees of freedom (or other degrees of freedom) of the machine. The projected machine force may then be multiplied by the machine velocity in each corresponding direction to determine an machine power metric matrix. The net power generation may then be obtained by comparing the input device power matrix and the machine power matrix, as shown in reference to FIG. Figure 4-Figure 5 As described, this can be used to determine the damping of the input device. The multiple values ​​in the matrix can correspond to different degrees of freedom of the input device that are damped. In fact, this process can allow the determination of damping coefficients of virtual dampers, each virtual damper corresponding to a degree of freedom of the input device. In this way, damping can be applied only in directions where the power comparison produces excess power. According to this method, damping can be applied in an anisotropic manner, where the damping is different along each degree of freedom based on the magnitude of the excess power along each corresponding degree of freedom. When the user operates the input device, damping can be applied only in the direction where the user input device moves.

[0059] Figure 6 The axes shown in are exemplary and, in some embodiments, may vary as the machine environment interaction or the input device environment interaction changes. Figure 6 In the example of FIG. 1 , if the environment contact direction is rotated 45 degrees about an axis coming straight out of the page, the axis used to determine the power metric and damping can also be rotated 45 degrees about the same axis. Thus, the damping coordinate system can be based on the direction in which the force is applied between the instrument and instrument environment and the input device and input device environment.

[0060] Figure 6 Depicted are exemplary machine power metrics and associated virtual dampers corresponding to the x and y translational degrees of freedom. The input device 106 may have one or more additional degrees of freedom, but to simplify the explanation, only the x and y translational degrees of freedom are shown. Figure 6 The right side of the figure shows the "follower" part of the manipulator. Figure 6As shown on the right, the distal portion 107 of the instrument 126 is pressed against the environment 500 with a force in the negative y direction, which is opposite to the direction indicated by the arrow P_y. The environment 500 can be a surface perpendicular to the y direction. Figure 6 As shown, the instrument power metric may reflect force and velocity in the y direction represented by arrow P_y. However, to simplify the explanation, and based on the force applied by instrument 126 and the movement of instrument 126 being directly in the direction represented by arrow P_y, there is no force applied to the instrument in the x direction. In this example, the power metric in the x direction would be a value associated with no power or energy being effectively present (e.g., "zero" or some other baseline value), and there would be no force applied to the instrument in the x direction. Figure 6 Shown in. Figure 6 The input device "leader" portion is shown on the left side of . On the input device side, an x-direction damper 103x and a y-direction damper 103y are shown. These dampers may be virtual dampers and represent passive or active forces applied to the input device based on a damping level determined according to the exemplary methods described herein. To simplify the explanation, dampers 103x and 103y are described here as being modeled by pure viscous damping, and in other embodiments, dampers with more complex or nonlinear damping responses may be used. Figure 6 In the example, the x-direction damper 103 has a damping coefficient B_x, and the y-direction damper 103y has a damping coefficient B_y. Figure 6 In the example shown, the apparatus power metric P_y can be "non-zero" and effectively indicate an amount of power or energy that is different from no power or no energy (for example, the power metric P_y can be zero, or a baseline value). A non-zero power metric P_y can result in excess energy, which is used to determine the y-direction damping coefficient B_y. For example, B_y can be set to be proportional to the difference between the apparatus power metric P_y and the corresponding y-direction input device power metric. Therefore, the input device 106 can be damped in the y-direction. In contrast, since the apparatus power metric in the x-direction is zero or less than or equal to the x-direction input device power metric, the x-direction damping coefficient B_x can be set to zero or another baseline value. In this way, damping can be applied to the input device in directions where excess power is generated to avoid instability in force feedback in these directions, while maintaining little or no damping in other stable directions without excess power so as not to hinder the user's feeling in these directions.

[0061] In some embodiments as described above, the power metric matrix may be integrated or otherwise accumulated over time to obtain an energy matrix. In some embodiments, such an energy matrix may be employed to determine a plurality of damping coefficients associated with each degree of freedom of the input device. In some embodiments, damping may be determined based on a gain value multiplied by a net energy matrix. Thus, the methods described herein with reference to one or more power matrices may instead be employed using energy calculations.

[0062] It should be noted that although in the plane example reference Figure 6 Two translational degrees of freedom (x and y) are shown and described, but in other embodiments, any suitable degrees of freedom may be employed, including any combination of translational and / or rotational degrees of freedom. For example, in some embodiments, power metrics and damping may be measured only in rotational degrees of freedom rather than in rotational degrees of freedom. Figure 6 The translational degrees of freedom are shown.

[0063] Figure 7 Graphs depicting experimental results of a computer-aided system according to some exemplary embodiments described herein. In particular, Figure 7 The data shown represent the movement of the device into and out of contact with the surface in its environment. In particular, the device moves into and out of contact in one direction. Figure 7 The data shown represent a single direction for determining force, power measurement, and damping, however Figure 7 The data in can be extended to multiple directions corresponding to multiple degrees of freedom.

[0064] As previously mentioned, in some embodiments, a method of controlling a computer-assisted system includes limiting the amount of damping applied to an input device. Figure 7 Depicted are the results of a method of implementing such a technique that improves user perception of performance while allowing for increased damping in unstable situations. In some embodiments, determining an amount of damping to be applied to an input device may include limiting the amount of damping to a damping limit. Such a damping limit is illustrated in the lower graph. In some embodiments, the damping limit may be static, while in other embodiments the damping limit may be adjusted to accommodate additional damping when appropriate. In some such embodiments, the damping limit may be configured to increase at a rate when the determined amount of damping exceeds a damping threshold. In some cases, the damping threshold and the damping limit may be the same, such that a determination that the amount of damping is greater than the imposed damping limit causes the damping limit to increase at that rate. The rate may be a maximum rate configured to limit the speed at which the damping limit increases, thereby eliminating rapid spikes in the damping of the input device. In some embodiments, the damping limit may increase in proportion to the determined amount of damping. Examples of damping limit increases are shown in FIG. Figure 7. In the depicted embodiment, the rate at which the damping is limited to increase is a linear slew rate. As the damping limit increases, the amount of damping applied to the input device may also increase. In some embodiments, the damping limit may be limited to a maximum damping limit, which may be determined based on the specific kinematics and application of the computer-assisted system.

[0065] exist Figure 7 In some of the illustrated embodiments, the damping limit may also be restored to its original value when additional damping is not needed. In some embodiments, the damping limit may be reduced when the amount of damping is less than the damping limit for a threshold period of time. Figure 7 In the example of , this is shown as the damping limit being reduced when the damping characteristic value drops below the limit. The threshold time period may be any suitable time period, including a period between 0 seconds and 1 second, between 0.01 seconds and 0.1 seconds, between 0.1 seconds and 0.5 seconds, or any other suitable range. In some embodiments, no time period may be used, and once the amount of damping determined is less than the damping limit, the damping limit may be reduced. In the example of Figure 7 In some of the embodiments shown, the damping limit can be reduced at another rate. That is, the damping limit can be configured to decrease at an upper rate so that the damping limit does not immediately return to the original value. This arrangement can be beneficial in providing stability during periods of time when there may be multiple interactions between the instrument and its environment in rapid succession. Figure 7 In the embodiment of FIG. 1 , the decreasing rate is a linear slew rate, but other arrangements are also envisioned, including exponential decay or other monotonically decreasing rates.

[0066] Figure 8 A flow chart of a method for operating a computer-assisted system according to some embodiments is depicted. In box 600, an instrument power metric is determined that indicates the amount of power of an instrument interaction. The instrument interaction includes a physical interaction between at least a portion of the instrument (e.g., a distal portion of the instrument, such as an end effector of the instrument) and an instrument environment containing the instrument. In some embodiments, the instrument interaction may include an interaction with tissue or other objects or non-solid materials, such as an interaction with a surface or mass of such objects or solid materials. As previously described, in some embodiments, the power metric may be determined with respect to multiple degrees of freedom, including any subset of the translational and rotational degrees of freedom of the instrument. As previously described, the instrument power metric may represent the energy of the interaction of the instrument with the instrument environment (e.g., the instantaneous power measured over a period of time, the amount of energy applied or received over the period of time). In box 602, an input device power metric is determined that indicates the amount of power of feedback provided by the input device in response to the instrument interaction. In some embodiments, the input device power metric may be determined over multiple degrees of freedom, including any subset of the translational and rotational degrees of freedom of the input device. The input device power metric may be determined, for example, as described in reference Figure 4described.

[0067] like Figure 8 As shown, in box 604, the damping to be applied to the input device is determined based on the instrument power metric and the input device power metric. For example, in some embodiments, the input device power metric and the instrument power metric are compared. This comparison can produce an excess power metric generated by a control loop for a computer-assisted system (e.g., a net energy comparison between the input device environment interaction and the instrument environment interaction). The excess power metric can be used to determine damping. In some embodiments, damping can be proportional to excess power. As previously described, the power metric can represent energy (e.g., power within a time period), and in some embodiments, the power can be integrated or summed over time to determine the power metric, which can be compared and used to determine the damping applied by the damping system. In box 606, the damping system is caused to apply the determined damping to the input device. In some embodiments, the damping system may include a physical damper, such as a brake, which can be adjusted to apply the determined damping. In other embodiments, the damping system may include an actuator system or cooperate with an actuator system to apply an active force to resist the movement of the input device according to the determined damping. In such an arrangement, the damping applied may be incorporated into the total force output commanded to a particular actuator. That is, in some embodiments, the application of damping may be incorporated into the total output force of the actuator. Figure 8 As shown, the method can be repeated as part of a control loop for a computer-aided system.

[0068] The above-mentioned embodiments of the technology described herein can be implemented in any of a variety of ways. For example, the embodiments can be implemented using hardware, software, or a combination thereof. When implemented in software, the software code can be executed on any suitable processor or processor set, whether provided in a single computer or distributed in multiple computers. Such a processor can be implemented as an integrated circuit, with one or more processors in an integrated circuit component, including commercial integrated circuit components known in the art, such as CPU chips, GPU chips, microprocessors, microcontrollers, or coprocessors. Alternatively, the processor can be implemented in a custom circuit system (such as an ASIC) or in a semi-custom circuit system generated by configuring a programmable logic device. As another alternative, the processor can be part of a larger circuit or semiconductor device, whether commercial, semi-custom, or custom. As a specific example, some commercial microprocessors have multiple cores, so that one or a subset of these cores can constitute a processor. However, the processor can be implemented using a circuit system of any suitable format.

[0069] Furthermore, it should be understood that a computer may be embodied in any of a variety of forms, such as a rack-mounted computer, a desktop computer, a laptop computer, or a tablet computer. In addition, a computer may be embedded in a device not generally regarded as a computer but having appropriate processing capabilities, including a personal digital assistant (PDA), a smart phone, or any other suitable portable or fixed electronic device.

[0070] In addition, the computer can have one or more input and output devices. Among other things, these devices can be used to present a user interface. The example of the output device that can be used to provide the user interface includes a printer or display screen for visual presentation output, and a loudspeaker or other sound generating device for auditory presentation output. The example of the input device that can be used for the user interface includes a keyboard and a pointing device, such as a mouse, a touch pad, and a digitizing tablet. As another example, the computer can receive input information by speech recognition or other auditory formats.

[0071] Such computers can be interconnected by one or more networks of any suitable form, including local area networks or wide area networks, such as enterprise networks or the Internet. Such networks can be based on any suitable technology and can operate according to any suitable protocol, and can include wireless networks, wired networks or fiber optic networks.

[0072] In addition, the various methods or processes outlined herein may be encoded as software that can be executed on one or more processors using any of a variety of operating systems or platforms. In addition, such software may be written using any of a variety of suitable programming languages ​​and / or programming or scripting tools, and may also be compiled into executable machine language code or intermediate code that is executed on a framework or virtual machine.

[0073] In this regard, the embodiments described herein may be embodied as a computer-readable storage medium (or multiple computer-readable media) (e.g., computer memory, one or more floppy disks, compact disks (CDs), optical disks, digital video disks (DVDs), tapes, flash memory, circuit configurations in field programmable gate arrays or other semiconductor devices, or other tangible computer storage media), which is encoded with one or more programs that, when executed on one or more computers or other processors, perform methods for implementing the various embodiments described above. As is apparent from the above examples, a computer-readable storage medium may retain information long enough to provide computer-executable instructions in a non-transient form. Such a computer-readable storage medium may be transportable so that one or more programs stored thereon may be loaded onto one or more different computers or other processors to implement various aspects of the present disclosure as described above. As used herein, the term "computer-readable storage medium" encompasses only non-transient computer-readable media that may be considered an article of manufacture (i.e., an article of manufacture) or a machine. Alternatively or additionally, the present disclosure may be embodied as a computer-readable medium other than a computer-readable storage medium, such as a propagating signal.

[0074] The term "program" or "software" is used in this article in a general sense to refer to any type of computer code or computer executable instruction set that can be used to program a computer or other processor to implement various aspects of the present disclosure as described above. In addition, it should be understood that according to one aspect of the present embodiment, one or more computer programs that perform the methods of the present disclosure when executed do not need to reside on a single computer or processor, but can be distributed in a modular manner between multiple different computers or processors to implement various aspects of the present disclosure.

[0075] Computer executable instructions may be in a variety of forms, such as program modules that are executed by one or more computers or other devices. Typically, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. Typically, in various embodiments, the functionality of the program modules may be combined or distributed as desired.

[0076] In addition, the data structure can be stored in a computer-readable medium in any suitable form. To simplify the description, the data structure can be shown as having fields that are related by sites in the data structure. This relationship can also be achieved by allocating storage for the fields with sites in the computer-readable medium, which conveys the relationship between the fields. However, any suitable mechanism can be used to establish the relationship between the information in the fields of the data structure, including by using pointers, tags, or other mechanisms that establish relationships between data elements.

[0077] The various aspects of the present disclosure may be used alone, in combination, or in various arrangements not specifically discussed in the above embodiments, and therefore its application is not limited to the details and arrangements of the components shown in the above description or the drawings. For example, an aspect described in one embodiment may be combined in any manner with an aspect described in other embodiments.

[0078] In addition, the embodiments described herein may be embodied as a method, examples of which have been provided. The actions performed as part of the method may be ordered in any suitable manner. Thus, embodiments may be constructed that perform actions in an order different from the order shown, which may include performing some actions simultaneously, even though shown as sequential actions in the illustrative embodiments.

[0079] Additionally, some actions are described as being taken by a “user.” It should be understood that a “user” is not necessarily a single individual, and in some embodiments, actions initiated by a “user” may be performed by a team of individuals and / or an individual in conjunction with computer-assisted tools or other mechanisms.

[0080] Although the present teaching is described in conjunction with various embodiments and examples, it is not intended that the present teaching is limited to these embodiments or examples. On the contrary, it will be appreciated by those skilled in the art that the present teaching encompasses various alternatives, modifications and equivalents. Therefore, the above description and accompanying drawings are intended only as examples.

Claims

1. A computer-aided system comprising: Manipulator arm; an input device configured to accept user commands to move the manipulator arm; a damping system coupled to the input device; as well as A controller comprising at least one processor, the controller being configured to: determining an instrument power metric indicative of an amount of power of an instrument interaction including a physical interaction between at least a portion of an instrument and an instrument environment containing the instrument, the instrument being supported by the manipulator arm, determining an input device power metric indicative of an amount of power of feedback provided by the input device in response to the instrument interaction, determining damping to be applied to the input device based on the instrument power metric and the input device power metric, and The damping system is caused to apply the damping to the input device.

2. The computer-assisted system of claim 1, wherein the portion of the instrument comprises a distal portion of the instrument.

3. The computer-aided system of claim 1 , wherein the controller is configured to determine the damping by: In response to the input device power metric being greater than or equal to the machine power metric, the amount of damping is set to minimum damping.

4. The computer-assisted system of claim 3, wherein the controller is configured to determine the damping further by: In response to the input device power metric being less than the machine power metric, the amount of damping is set to a higher damping that is greater than the minimum damping.

5. A computer-assisted system according to claim 1, wherein when the machine power metric is greater than the input device power metric, the amount of damping to be applied to the input device has a positive monotonic relationship with the amount by which the machine power metric is greater than the input device power metric.

6. The computer-assisted system of claim 5, wherein the positive monotonic relationship is a strictly monotonic relationship.

7. The computer-assisted system of claim 5, wherein the amount by which the machine power metric is greater than the input device power metric comprises the amount of the machine power metric minus the amount of the input device power metric.

8. The computer-aided system of claim 1, wherein: The controller is configured to determine the damping by: A damping coefficient is determined based on a difference between the machine power metric and the input device power metric.

9. The computer-assisted system of claim 8, wherein in the event that the machine power metric is greater than the input device power metric, the damping coefficient is proportional to the difference for a first range of difference values.

10. The computer-aided system of claim 9, wherein: In a case where the apparatus power metric is greater than the input device power metric, the damping factor is non-proportional to the difference for a second range of the difference, wherein the second range is different than the first range; or In the event that the machine power metric is not greater than the input device power metric, the damping coefficient is non-proportional to the difference for a third range of difference values.

11. The computer-aided system according to any one of claims 1 to 10, wherein the controller is configured to determine the damping by: The amount of the damping is limited to a damping limit.

12. The computer-aided system of claim 11, wherein the controller is further configured to: In response to determining that the amount of damping is greater than a damping threshold, the damping limit is increased at a first rate.

13. The computer-assisted system of claim 12, wherein the controller is further configured to: The damping limit is constrained not to exceed a maximum damping limit.

14. The computer-assisted system of claim 12, wherein the controller is further configured to: In response to the amount of the damping being less than the damping limit for a threshold period of time, the damping limit is reduced.

15. The computer-assisted system of any one of claims 1 to 10, wherein the controller is configured to cause the damping system to apply the damping to the input device by: causing physical adjustment of an adjustable damper of said damping system; driving an actuator system to apply an active damping force or torque to the input device; or A braking system of the damping system is caused to apply a braking force to the input device.

16. The computer-assisted system of any one of claims 1 to 10, wherein the controller is configured to cause the damping system to apply the damping to the input device by: An actuator system is driven to apply an active damping force or torque to the input device in a direction opposite to the direction of motion of the input device.

17. A computer-aided system according to any one of claims 1 to 10, wherein: The controller is configured to determine the appliance power metric by determining an accumulation of power of the appliance interactions over a period of time; and The controller is configured to determine the input device power metric by determining an accumulation of power of the input device interactions over the time period.

18. The computer-assisted system of claim 17, wherein: The controller is configured to determine the appliance power metric further by reducing the accumulation of the power of the appliance interactions over time; and The controller is configured to determine the input device power metric further by reducing the accumulation of the power of the input device interactions over the passage of time.

19. A computer-aided system according to any one of claims 1 to 10, wherein: The controller is configured to determine the machine power metric by determining at least one product selected from the group consisting of: the product of the translational velocity of the instrument along the instrument translational degree of freedom and the force applied by the instrument to the instrument environment in the instrument translational degree of freedom, and the product of the rotational speed of the instrument along the instrument rotational degree of freedom and the torque applied by the instrument to the instrument environment in the instrument rotational degree of freedom; and The controller is configured to determine the input device power metric by determining at least one product selected from the group consisting of: the product of the translational velocity of the input device in the input device translational degree of freedom and the force applied by the input device to the input device environment in the input device translational degree of freedom, and The product of the rotational velocity of the input device in the input device rotational degree of freedom and the torque applied by the input device to the input device environment in the input device rotational degree of freedom.

20. A computer-aided system according to any one of claims 1 to 10, wherein: The computer-assisted system is configured to move the instrument in a plurality of instrument degrees of freedom; The input device is configured to move in a plurality of input device degrees of freedom, each degree of freedom of the plurality of input device degrees of freedom corresponding to a degree of freedom of the plurality of instrument degrees of freedom; The controller is configured to determine the machine power metric by: for each of a plurality of non-parallel machine degrees of freedom, calculating a machine power component based on a product of a machine velocity and a machine force in the machine degree of freedom; The controller is configured to determine the input device power metric by: for each degree of freedom of a plurality of input device degrees of freedom, calculating an input device power component based on a product of an input device velocity and an input device force in the input device degree of freedom; and The controller is configured to determine the damping by, for each of the plurality of input device degrees of freedom, determining an amount of damping in the input device degree of freedom based on the input device power component along the input device degree of freedom and the machine power component along the degree of freedom corresponding to the input device degree of freedom.

21. The computer-assisted system of claim 20, wherein: The plurality of instrument degrees of freedom include a first instrument translation degree of freedom, a second instrument translation degree of freedom, and a third instrument translation degree of freedom; and The plurality of input device degrees of freedom include a first input device translational degree of freedom associated with the first instrument translational degree of freedom, a second input device translational degree of freedom associated with the second instrument translational degree of freedom, and a third input device translational degree of freedom associated with the third instrument translational degree of freedom.

22. A method of controlling a computer-assisted system comprising a manipulator arm, an input device configured to accept user commands to move an implement, and a damping system coupled to the input device, the method comprising: determining an instrument power metric indicative of an amount of power of an instrument interaction including a physical interaction between at least a portion of an instrument and an instrument environment containing the instrument, the instrument being supported by the manipulator arm; determining an input device power metric indicative of an amount of power of feedback provided by the input device in response to the instrument interaction; determining damping to apply to the input device based on the instrument power metric and the input device power metric; as well as The damping system is caused to apply the damping to the input device.

23. The method of claim 22, wherein determining the damping comprises: In response to the input device power metric being greater than the machine power metric, the amount of damping is set to minimum damping.

24. The method of claim 23, wherein determining the damping further comprises: In response to the input device power metric being less than the machine power metric, the amount of damping is set to a higher damping that is greater than the minimum damping.

25. The method of claim 22, wherein when the apparatus power metric is greater than the input device power metric, the amount of damping to be applied to the input device has a positive monotonic relationship to the amount by which the apparatus power metric is greater than the input device power metric.

26. The method of claim 22, wherein determining the damping comprises: A damping coefficient is determined based on a difference between the machine power metric and the input device power metric.

27. The method of claim 26, wherein determining the damping coefficient based on the difference between the machine power metric and the input device power metric comprises: In a case where the apparatus power metric is greater than the input device power metric, determining the damping coefficient in proportion to the difference for a first range of difference values; as well as In the event that the machine power metric is greater than the input device power metric, the damping coefficient is determined disproportionately for a second range of difference values, the second range being different from the first range.

28. The method of any one of claims 23 to 27, wherein determining the damping comprises limiting the amount of the damping to a damping limit.

29. The method according to claim 28, further comprising: In response to determining that the amount of damping is greater than a damping threshold, increasing the damping limit at a first rate; as well as The damping limit is constrained not to exceed a maximum damping limit.

30. The method of claim 28, further comprising: In response to the amount of the damping being less than the damping limit for a threshold period of time, the damping limit is reduced.

31. The method according to any one of claims 22 to 27, wherein: Determining the device power metric includes determining an accumulation of power of the device interactions over a period of time; and Determining the input device power metric includes determining an accumulation of power of the input device interactions over the time period.

32. The method of claim 31, wherein: Determining the instrument power metric further comprises reducing the accumulation of the power of the instrument interactions over time; and Determining the input device metric further includes reducing the accumulation of the power of the input device interactions over the passage of time.

33. A method according to any one of claims 22 to 27, wherein: Determining the instrument power metric includes determining at least one product selected from the group consisting of: the product of the translational velocity of the instrument along the instrument translational degree of freedom and the force applied by the instrument to the instrument environment along the instrument translational degree of freedom, and the product of the rotational velocity of the instrument along the instrument rotational degree of freedom and the torque applied by the instrument to the instrument environment along the instrument rotational degree of freedom; and Determining the input device power metric includes determining at least one product selected from the group consisting of: a product of a translation velocity of the input device in the input device translation degree of freedom and a force applied by the input device to the input device environment in the input device translation degree of freedom; as well as The product of the rotational velocity of the input device in the input device rotational degree of freedom and the torque applied by the input device to the input device environment in the input device rotational degree of freedom.

34. A method according to any one of claims 22 to 27, wherein: The computer-assisted system is configured to move the instrument in a plurality of instrument degrees of freedom; The input device is configured to move in a plurality of input device degrees of freedom, each degree of freedom of the plurality of input device degrees of freedom corresponding to a degree of freedom of the plurality of instrument degrees of freedom; Determining the instrument power metric includes: for each of a plurality of non-parallel instrument degrees of freedom, calculating an instrument power component based on a product of an instrument velocity and an instrument force along the instrument degree of freedom; Determining the input device power metric includes: for each of a plurality of input device degrees of freedom, calculating an input device power component based on a product of an input device velocity and an input device force or torque in the input device degree of freedom; and Determining the damping includes determining, for each of the plurality of input device degrees of freedom, an amount of damping in the input device degree of freedom based on the input device power component along the input device degree of freedom and the machine power component along the degree of freedom corresponding to the input device degree of freedom.

35. At least one non-transitory computer-readable storage medium storing programming instructions that, when executed by at least one processor associated with a computer-assisted system, cause the at least one processor to perform the method of any one of claims 22 to 34.

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