System and method for disconnect clutch in an articulated arm

Abstract

Systems and methods for a breakaway clutch in an articulated arm. Systems and methods for a breakaway clutch in a computer-assisted medical device include an articulated arm having one or more first joints and a control unit coupled to the articulated arm and having one or more processors. The control unit operates each of the first joints in a plurality of states. The plurality of states include: a locked state, in which movement of the respective first joint is restricted; and a floating state, in which movement of the respective first joint is permitted. When an excitation on a second joint selected from the first joint exceeds one or more unlocking thresholds, the control unit further switches one or more second joints selected from the first joint from the locked state to the floating state, and when a velocity of each of the second joints is below one or more locking thresholds, the control unit further switches the second joints from the floating state to the locked state.

Description

[0001] This application is a divisional application of Chinese patent application 2015800129316 (PCT / US2015 / 021074) filed on March 17, 2015 and entitled “System and method for decoupling in an articulated arm”.

[0002] Related Applications

[0003] The present disclosure claims priority to US Provisional Patent Application No. 61 / 954,120, filed on March 17, 2014, entitled “SYSTEM AND METHOD FOR DISCONNECT CLUTCH IN AN ARTICULATED ARM,” which is incorporated herein by reference in its entirety. Technical Field

[0004] The present disclosure relates generally to the operation of equipment with articulated arms, and more particularly to the disconnect clutching of the articulated arms. Background Art

[0005] More and more equipment is being replaced by autonomous and semi-autonomous electronic devices. This is especially true in today's hospitals where a large array of autonomous and semi-autonomous electronic devices are found in operating rooms, interventional rooms, intensive care units, emergency rooms, etc. For example, glass and mercury thermometers are being replaced by electronic thermometers, IV drip lines now include electronic monitors and flow regulators, and traditional handheld surgical instruments are being replaced by computer-assisted medical devices.

[0006] These electronic devices provide both advantages and challenges to the personnel who operate them. Many of these electronic devices may be capable of autonomous or semi-autonomous movement of one or more articulated arms and / or end effectors. Before these articulated arms and their end effectors can be used, they are usually moved to or near the desired working position and orientation. This movement can be performed by remote operation or remote operation using one or more user input controls. As the complexity of these electronic devices increases and the articulated arms include a large number of degrees of freedom, it can become complicated and / or time-consuming to move to the desired working position and orientation by remote operation. In order to streamline the operation, some articulated arms include a clutched or floating state, in which one or more of the brakes and / or actuators on the joints of the articulated arm are released, thereby allowing the operator to manually change the position and / or orientation of the articulated arm via direct manipulation. In this way, the articulated arm can be quickly and easily placed and / or oriented as needed. The clutched or floating state is often engaged by manually activating one or more clutch controls on the articulated arm and / or selecting the clutched or floating state at the operator console. This type of manual activation may be inconvenient and / or imprudent.

[0007] Therefore, there is a need for improved methods and systems for clutching an articulated arm. Summary of the invention

[0008] In accordance with some embodiments, a computer-assisted medical device includes an articulated arm having one or more first joints and a control unit coupled to the articulated arm and having one or more processors. The control unit operates each of the first joints in a plurality of states. The plurality of states include: a locked state, in which movement of the respective first joint is restricted; and a floating state, in which movement of the respective first joint is permitted. When an excitation on a second joint selected from the first joint exceeds one or more unlocking thresholds, the control unit further switches one or more second joints selected from the first joint from the locked state to the floating state, and when a velocity of each of the second joints is below one or more locking thresholds, the control unit further switches the second joints from the floating state to the locked state.

[0009] In accordance with some embodiments, a method of controlling movement of a medical device includes operating each of one or more first joints of an articulated arm of the medical device in one of a plurality of states. The plurality of states include: a locked state, in which movement of the respective joint is restricted; and a floating state, in which movement of the respective joint is permitted. The method also includes: determining an excitation on one or more second joints selected from the joints; switching the second joints from the locked state to the floating state when the excitation exceeds one or more unlocking thresholds; determining a velocity of each of the second joints; and switching the second joints from the floating state to the locked state when the velocity of each of the second joints is below one or more locking thresholds.

[0010] Consistent with some embodiments, a non-transitory machine-readable medium includes a plurality of machine-readable instructions that, when executed by one or more processors associated with a medical device, are adapted to cause the one or more processors to perform a method. The method includes operating each of one or more first joints of an articulated arm of a medical device in one of a plurality of states. The plurality of states include: a locked state, in which movement of the respective joints is restricted; and a floating state, in which movement of the respective joints is permitted. The method also includes: determining an excitation on one or more second joints selected from the first joint; switching the second joints from the locked state to the floating state when the excitation exceeds one or more unlocking thresholds; determining a velocity of each of the second joints; and switching the second joints from the floating state to the locked state when the velocity of each of the second joints is below one or more locking thresholds. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a simplified diagram of a computer-assisted system according to some embodiments.

[0012] Figure 2 is a simplified diagram illustrating an articulated arm, according to some embodiments.

[0013] Figure 3 is a simplified diagram of a split clutching method according to some embodiments.

[0014] In the drawings, elements with the same name have the same or similar functions. DETAILED DESCRIPTION

[0015] In the following description, the specific details of some embodiments consistent with the present disclosure are set forth. However, it will be apparent to those skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are intended to be illustrative but not restrictive. Those skilled in the art may recognize other elements within the scope and spirit of the present disclosure, although not specifically described herein. In addition, to avoid unnecessary repetition, one or more features shown and described associated with one embodiment may be incorporated into other embodiments, unless otherwise specifically described or if one or more features will render the embodiment nonfunctional.

[0016] Figure 1 is a simplified diagram of a computer-assisted system 100 according to some embodiments. Figure 1 As shown, the computer-assisted system 100 includes an apparatus 110 with one or more movable arms or articulated arms 120. Each of the one or more articulated arms 120 can support one or more end effectors. In some examples, the apparatus 110 can be consistent with a computer-assisted surgical apparatus. Each of the one or more articulated arms 120 provides support for surgical instruments, imaging devices, and / or the like. The apparatus 110 can be further coupled to an operator workstation (not shown), which can include one or more master controls for operating the apparatus 110, the one or more articulated arms 120, and / or the end effectors. In some embodiments, the apparatus 110 and the operator workstation can correspond to the da Vinci surgical system commercialized by Intuitive Surgical, Inc. of Sunnyvale, California. In some embodiments, computer-assisted surgical apparatus with other configurations, fewer or more articulated arms, and / or the like can be used with the computer-assisted system 100.

[0017] The device 110 is coupled to a control unit 130 via an interface. The interface may include one or more cables, connectors, and / or buses and may also include one or more networks with one or more network switches and / or routing devices. The control unit 130 includes a processor 140 coupled to a memory 150. The operation of the control unit 130 is controlled by the processor 140. And although the control unit 130 is shown with only one processor 140, it should be understood that the processor 140 may represent one or more central processing units, multi-core processors, microprocessors, microcontrollers, digital signal processors, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and / or the like in the control unit 130. The control unit 130 may be implemented as a separate subsystem and / or board added to a computing device or as a virtual machine. In some embodiments, the control unit may be included as part of an operator workstation and / or independent of the operator workstation but coordinated with the operator workstation.

[0018] The memory 150 may be used to store software executed by the control unit 130 and / or one or more data structures used during the operation of the control unit 130. The memory 150 may include one or more types of machine-readable media. Some common forms of machine-readable media may include floppy disks, diskettes, hard disks, magnetic tapes. Any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tapes, any other physical media with hole patterns, RAM, PROMs, EPROMs, FLASH-EPROMs, any other memory chips or cassettes, or any other media from which a processor or computer is adapted to read.

[0019] As shown, the memory 150 includes a motion control application 160 that can be used to support autonomous and / or semi-autonomous control of the device 110. The motion control application 160 may include one or more application program interfaces (APIs) for receiving position, motion, and / or other sensor information from the device 110, exchanging position, motion, and / or collision avoidance information with other control units associated with other devices, and / or planning and / or assisting in planning motion for the device 110, the articulated arm 120, and / or the end effector of the device 110. And while the motion control application 160 is described as a software application, the motion control application 160 may be implemented using hardware, software, and / or a combination of hardware and software.

[0020] In some embodiments, the computer-assisted system 100 may be found in an operating room and / or an interventional room. And while the computer-assisted system 100 includes only one device 110 with two articulated arms 120, a person of ordinary skill will appreciate that the computer-assisted system 100 may include any number of devices with articulated arms and / or end effectors of similar and / or different designs than the device 110. In some instances, each of the devices may include fewer or more articulated arms and / or end effectors.

[0021] Figure 2 2 is a simplified diagram showing an articulated arm 200 according to some embodiments. For example, the articulated arm 200 may be a part of one of the articulated arms 120 in the device 110. Figure 2 As shown, the articulated arm 200 includes various links and joints. The most proximal end of the articulated arm 200 is coupled to the platform 210. In some examples, the platform 210 may be at the distal end of additional joints and links (not shown) from a computer-aided device. Coupled to the platform 210 is a series of set-up joints and links 220. The set-up joints and links 220 are rotationally coupled to the platform 210 via a first set-up linkage joint 222. In some examples, additional set-up links and joints for other articulated arms (not shown) may be rotationally coupled to the platform 210 using additional first set-up linkage joints. Coupled to the first set-up linkage joint 222 is a set-up base linkage 224, which is coupled to the proximal end of a set-up extension link 226 via a first set-up linkage prismatic joint 228. The distal end of the set-up extension link 226 is coupled to the proximal end of a set-up vertical link 230 via a second set-up linkage prismatic joint 232. The distal end of the combined linkage vertical link 230 is rotationally coupled to the proximal end of the support link 234 via the second combined linkage joint 236. A first rotation joint 238 is coupled to the distal end of the support link 234. The first rotation joint 238 provides rotational control on additional links and joints located distal to the first rotation joint 238. In some examples, the central axis 250 of the first rotation joint 238 can be aligned with a remote center 290 that can be fixed in place during remote operation of the articulated arm 200.

[0022] The coupling link 240 couples the first rotation joint 238 to the second rotation joint 242. The second rotation joint 240 is coupled to the yaw joint 252 via a yaw link 254. Coupled distally to the yaw joint 252 is a parallelogram pitch mechanism 260. At the proximal end of the parallelogram pitch mechanism 260 is a first pitch link 262 coupling the yaw joint 252 to the first pitch joint 264. The second pitch link 266 couples the first pitch joint 264 to the second pitch joint 268. The third pitch link 270 couples the second pitch joint 268 to the third pitch joint 272. The instrument carriage is coupled to the third pitch joint 272 and includes an instrument shaft 280. One or more end effectors may be coupled to the distal end of the instrument shaft 820. In some examples, the parallelogram pitch mechanism 260 may be controlled to maintain alignment of the instrument shaft 280 with the distal center 290.

[0023] like Figure 2 As shown, the articulated arm 200 includes a number of linkages 224, 226, 230, 234, 240, 254, 262, 266, 270, and 280, whose relative positions and / or orientations can be adjusted using a number of prismatic joints 228 and 232 and a number of revolute joints 222, 236, 238, 242, 262, 264, 268, and 272. Each of the prismatic joints and the revolute joints can include one or more sensors for sensing position, rotation, movement, force, torque, and / or the like on the respective joint.

[0024] Each of the various joints may be a non-actuated or an actuated joint, depending on the desired ability to control the articulated arm 200. In some examples, a non-actuated joint may not include any actuators such that it cannot be moved via remote operation and / or motion control commands from a control unit for the articulated arm 200. In some examples, a non-actuated joint may include a brake that permits the control unit to prevent and / or limit movement in the non-actuated joint. Figure 2 In some examples, joints 228, 232, and / or 236 may be non-actuated joints. In some examples, an actuated joint may include one or more actuators that can control the movement of the actuated joint via remote operation and / or motion commands. In some examples, the actuated joint may also include a brake.

[0025] In some embodiments, to prevent unwanted movement, the various joints and links in the articulated arm 200 can be placed in a locked state in which each of the non-actuated joint brakes is activated and each of the actuated joint actuators is commanded to hold the actuated joint at a commanded position. In some examples, the locked state can additionally prevent unwanted movement due to gravity acting on the articulated arm 200. Although Figure 2210 . Although not shown in the drawings, the articulated arm 200 may include one or more clutch buttons or controls. In some instances, the clutch buttons may be located at various locations along the instrument carriage. In some instances, additional clutch controls may be activated via operator controls at the operator console. By activating one or more of the clutch buttons or controls, one or more joints of the articulated arm may be switched from a locked state to a clutched or floating state, in which at least some of the non-actuated joint brakes may be at least partially released and at least some of the actuated joint actuators may permit movement of the joint away from the command position. For example, activation of a clutch button located on the articulated arm 200 may place the articulated arm 200 in a floating state, while other portions of the computer-aided device coupled to the platform 210 remain in a locked state. While the joints of the articulated arm 200 are in a floating state, the operator may manually place and / or direct the articulated arm 200 to a desired working position and orientation.

[0026] In some embodiments, manual activation of the clutch mechanism of articulated arm 200 may not often be practical and / or prudent. In some instances, the position of the clutch button or control may not be convenient for easy activation by the operator. In some instances, the operator may not have idle fingers and / or hands to operate the clutch control. In some instances, the coordination of the clutch control with another operator at the operator console is impossible and / or impractical. In some instances, the operator may not be able to operate the clutch control without breaking the sterile area set up around the part of the articulated arm 200. Therefore, it will be advantageous to make at least part of the articulated arm 200 enter a floating state without activating the clutch control by the operator.

[0027] In some embodiments, movement of the articulated arm 200 without manual clutch activation may be desired. In some instances, unintentional collisions may occur between an operator, a patient, and / or an object and one or more links and / or joints of the articulated arm 200. In some instances, these unintentional collisions may cause injury to the operator, injury to the patient, damage to the object, and / or damage to the articulated arm 200 due to the rigid position and / or orientation maintained by the articulated arm 200. In some instances, being able to detect unintentional collisions and automatically bring the articulated arm 200 into a floating state may reduce injury to the operator, injury to the patient, damage to the object, and / or damage to the articulated arm 200.

[0028] Figure 33 is a simplified diagram of a method 300 for disconnect clutching according to some embodiments. One or more of the processes 310-360 of the method 300 may be implemented at least in part in the form of executable code stored on a non-transitory tangible machine-readable medium, which, when executed by one or more processors (e.g., processor 140 in control unit 130), may cause the one or more processors to perform one or more of the processes 310-360. In some embodiments, the method 300 may be performed by an application such as motion control application 160.

[0029] At process 310, a locked state is entered. The joints of an articulated arm, such as articulated arms 120 and / or 200, may be placed in a locked state by default. In the locked state, movement of the articulated arm may be prevented and / or reduced by activating a brake in each of the non-actuated joints of the articulated arm and maintaining each of the actuated joints of the articulated arm at a respective commanded position using a corresponding actuated joint actuator.

[0030] At process 320, an external excitation on one or more joints is determined. One or more sensors associated with each of the joints of the articulated arm may be periodically read and / or monitored to determine whether there is any external excitation applied to one or more joints of the articulated arm. In some instances, a linear sensor associated with a prismatic joint and / or a rotation sensor associated with a rotary joint is monitored to determine the actual position of each joint. In some instances, a position error may be determined based on the difference between the actual position in the actuated joint and the command position and / or the brake position in the non-actuated joint. In some instances, the position error may be converted into a force and / or torque close to the force on the respective joint by using one or more dynamic models, inverse Jacobi transposition matrixes and / or control models for the respective joints. In some instances, the force and / or torque on the respective joints may be measured using force and / or torque sensors, respectively, to monitor the respective joints. In some instances, the joint velocity of the actuated joint may also be determined using one or more velocity sensors associated with the actuated joint or determined digitally based on the change in the actual position of the actuated joint.

[0031] At process 330, it is determined whether the external excitation on any joint exceeds the unlocking threshold. The external excitation value for each of the joints determined during process 320 is compared to one or more unlocking thresholds to determine whether any unlocking threshold is exceeded. In some instances, when any external joint excitation value exceeds the corresponding unlocking threshold, the joint of the articulated arm can be switched to a floating state using process 340. In some instances, when a combination of two or more of the external joint excitation values ​​exceeds the corresponding unlocking threshold, the joint of the articulated arm can be switched to a floating state. In some instances, when a weighted and / or unweighted set of external excitations from two or more joints exceeds a composite unlocking threshold, the joint of the articulated arm can be switched to a floating state. In some instances, the set can include an average, a median, a sum of squares, a minimum, a maximum, and / or the like.

[0032] In some instances, each of the unlocking thresholds for the respective joints may be different, depending on the position and / or purpose of the respective joints in the articulated arm. In some instances, the unlocking threshold may be adjusted based on the current posture, position, and / or orientation of the articulated arm. In some instances, the unlocking threshold for the respective joints may be adjusted and / or disabled when the respective joints cross a soft stop near the end of the possible movement of the respective joints. In some instances, the floating state may be activated by default when the respective joints cross the soft stop. In some instances, determining whether the external excitation exceeds the threshold may be limited to a subset of the joints in the articulated arm. In some instances, the external excitation on the braked non-actuated joints may not be monitored during process 320 and may not have a corresponding unlocking threshold. In some instances, the unlocking threshold may be adjusted based on the size and / or mass of the articulated arm. In some instances, the unlocking threshold may be large enough to avoid accidentally switching to the floating state due to gravity and / or errors in the joint sensors.

[0033] In some instances, the unlocking threshold may correspond to a threshold value associated with a position error between the actual position of the joint and the commanded position and / or brake position of the joint. In some instances, the threshold value for a prismatic joint may be between 0.02 mm and 5 mm. In some instances, the threshold value for a rotary joint may be between 0.03 degrees and 0.5 degrees. In some instances, one or more unlocking threshold values ​​may correspond to a force and / or torque applied to the joint, as measured and / or as determined during process 320. In some instances, the threshold value for the force on a prismatic joint may be between 1 N and 30 N. In some instances, the threshold value for the torque on a rotary joint may be between 1 N-m and 30 N-m. In some instances, the threshold value may exceed a force and / or torque saturation value for the joint.

[0034] In some embodiments, before the articulated arm is switched to the floating state, the unlocking threshold should be exceeded for a predetermined time period. In some instances, the joint of the articulated arm may be switched to the floating state when the respective external excitation values ​​continuously exceed the corresponding unlocking threshold for a predetermined time period. In some instances, the joint of the articulated arm may be switched to the floating state when the set of respective external excitation values ​​(such as an average value) exceeds the respective excitation value for a predetermined time period. In some instances, a sliding window and / or exponential smoothing method may be used to determine the set. In some instances, a filter may be used on the sensed external excitation emphasizing the intermediate frequency to better isolate interference due to human intention from interference due to gravity and other environmental factors that may be at low frequencies. In some instances, the intermediate frequency may extend from about 0.01 Hz to 10 Hz. In some instances, a discrete wavelet transform may be used instead of a filter or in combination with a filter to better isolate interference due to human intention. In some instances, the predetermined time period may be set by an operator. In some instances, the predetermined time period may be between 50 milliseconds and 150 milliseconds. In some examples, the predetermined time period may be a first time period away from activating the breakaway clutch to avoid accidentally switching to a floating state due to residual momentum in the articulated arm due to other recently completed motions and / or steady-state disturbances from the environment that are confused with user input. In some examples, prior to the first time period of activating the breakaway clutch, a locked state should be established with the external stimulus below the unlock threshold for a predetermined time period to avoid accidentally switching to a floating state due to possible transient conditions (such as when the articulated arm is detached from the patient, an end effector is attached or removed from the articulated arm, and / or the like). In some examples, the predetermined time may extend between an additional 100 milliseconds and 250 milliseconds after enabling the breakaway clutch.

[0035] When the external stimulus does not exceed the one or more unlocking thresholds, the external stimulus is again determined using process 320. When the external stimulus exceeds the one or more unlocking thresholds, the joints of the articulated arm are switched to a floating state using process 340.

[0036] At process 340, a floating state is entered. One or more of the joints of the articulated arm are placed in a floating state that allows free and / or mostly free movement of the joint. In some instances, the joints placed in the floating state may be a subset of the joints in the articulated arm. In some instances, this allows a split clutch to be applied to those parts of the articulated arm that are subjected to external excitation. In some instances, the brakes on each of the non-actuated joints placed in the floating state may be released to allow movement of each of the non-actuated joints. In some instances, each of the actuated joints placed in the floating state may be commanded to move to an actual position determined during process 320 or when the actuated joint is maintained in the floating state. In some instances, each of the actuated joints placed in the floating state may also be commanded to match the joint speed determined during process 320 or when the actuated joint is maintained in the floating state. In some instances, setting the command position of a feedback controller of an actuated joint to an actual position and / or setting the command velocity of the feedback controller to an actual joint velocity creates the impression that the actuated joint is moving freely, and when gravity compensation is also being applied, this is also accompanied by the impression of apparent weightlessness.

[0037] In some embodiments, the movement of the joint in the floating state may be damped. In order to reduce and / or prevent unrestricted movement and / or frantic movement of the articulated arm while in the floating state, one or more of the joints placed in the floating state may be subjected to some form of damped motion. For example, it is undesirable for an articulated arm subjected to a strong external excitation (such as a hard collision) to move away from the strong external excitation without certain restrictions. Constraining the clutch motion can reduce the risk of damage and / or damage caused by the fast-moving articulated arm. In some examples, the damped motion can be implemented on the non-actuated joint by partially releasing the brake to slow down the movement of the non-actuated joint. In some examples, the brake can be partially released by controlling one or more voltages, currents, duty cycles, and / or the like of the signal used to control the brake. In some examples, the damped motion can be implemented on the actuated joint by commanding the actuated joint to move a portion of the distance behind the actual position based on the direction of motion, by increasing the derivative constant of the feedback controller without significantly affecting its stability margin, and / or by introducing a reverse current and / or voltage on the actuator of the actuated joint to emulate a resisting force and / or a resisting torque. In some examples, the damping motion can be implemented on the actuated joint by commanding the velocity of the actuated joint to a value that is lower than the joint velocity determined during process 320 or when the actuated joint is held in a floating state. In some examples, the damping motion can be adjusted to account for the current attitude, position, and / or orientation of the articulated arm, the size and / or mass of the articulated arm, and / or the like.

[0038] In some embodiments, one or more of the joints in the articulated arm that are not placed in a floating state may be subject to compliant motion restrictions. In some instances, the joints that are not placed in a floating state may be commanded to one or more positions and / or orientations in response to detected movement of the joints that are placed in a floating state. In some instances, the joints that are not placed in a floating state may be commanded to one or more positions and / or orientations. Figure 2 In the example of , one or more of the joints in the parallelogram pitch mechanism 260 may be commanded to maintain the instrument shaft 280 intersecting the central axis 250 at the distal center 290 .

[0039] At process 350, joint speed is determined. One or more sensors associated with each of the joints of the articulated arm are periodically read and / or monitored to determine the speed of each of the joints in the floating state. In some instances, the change in linear and / or rotational position between two consecutive monitoring intervals is used to estimate the joint speed. In some instances, numerical or other differentiation techniques may be used to determine the joint speed based on the sensed position. In some instances, speed sensors on the joints may be monitored.

[0040] At process 360, it is determined whether the joint speed drops below the locking threshold. During the split clutch, the joint of the articulated arm remains in a floating state as long as continued motion of the articulated arm is detected. The joint speed determined during process 350 is compared with one or more locking thresholds to determine whether any continued motion is detected in the articulated arm. In some instances, each of the joint speeds may be compared with a corresponding locking threshold. When each of the joint speeds is below its corresponding locking threshold, lack of motion is detected and the joint of the articulated arm is switched to a locked state using process 310. In some instances, when a weighted and / or unweighted set of joint speeds from each of the joints is below a composite locking threshold, the joint of the articulated arm is switched to a locked state using process 310. In some instances, the set may include an average, a median, a sum of squares, a minimum, a maximum, and / or the like.

[0041] In some instances, each of the locking thresholds for the respective joints in the articulated arm may be different, depending on the location and / or purpose of the respective joints in the articulated arm. In some instances, the locking thresholds may be adjusted based on the current posture, position, and / or orientation of the articulated arm. In some instances, the locking thresholds for the respective joints may be adjusted and / or disabled when the respective joints pass through a soft stop near the end of the possible motion for the respective joints. In some instances, the locking state may be activated by default when the respective joints pass through the soft stop. In some instances, determining whether the joint speed is below the locking threshold may be limited to a subset of the joints in the articulated arm. In some instances, the locking threshold may be adjusted based on the size and / or mass of the articulated arm. In some instances, the locking threshold may be large enough to avoid accidentally switching to a locked state due to errors in the joint sensors.

[0042] In some examples, the locking threshold for a prismatic joint may be between 0.1 and 10 millimeters per second. In some examples, the threshold for a rotary joint may be between 0.25 and 10 degrees per second.

[0043] In some embodiments, before the joint of the articulated arm is switched to the locked state, the joint speed should remain below the locking threshold for a predetermined time period. In some instances, the joint of the articulated arm may be switched to the locked state when the joint speed is continuously below the corresponding locking threshold for a predetermined time period. In some instances, the joint of the articulated arm may be switched to the locked state when a set of respective joint speeds (such as an average value) is below the respective locking threshold for a predetermined time period. In some instances, a sliding window and / or exponential smoothing method may be used to determine the set. In some instances, the predetermined time period may be set by an operator. In some instances, the predetermined time period may be between 100 milliseconds and 200 milliseconds.

[0044] When the joint speed remains above the locking threshold, the joint speed is again determined using process 350. When the joint speed is below the locking threshold, the joints of the articulated arm are switched to a locked state using process 310.

[0045] As stated above and as further emphasized herein, Figure 3These are merely examples that should not unduly limit the scope of the claims. One of ordinary skill in the art will appreciate many variations, substitutions, and modifications. According to some embodiments, the breakaway clutch of method 300 may be disabled during certain modes of operation of the articulated arm. In some instances, the breakaway clutch may be disabled when the articulated arm is in a hard-locked state during storage and / or when a cart on which the articulated arm is mounted is being transported between locations. In some instances, the breakaway clutch may be disabled when the articulated arm is in an actuated remote operation mode and / or performing a commanded motion, such as when docked to a patient. In some instances, disabling the breakaway clutch during an actuated operation may reduce the likelihood that manual interference and / or collision with the articulated arm will interfere with remote operation and / or commanded motion, and thus reduce the further likelihood of damaging the object being manipulated and / or causing injury to the patient on whom the articulated arm is being used. In some instances, the breakaway clutch may be adjusted, prompted, or disabled when any joint in the articulated arm passes a soft stop position.

[0046] Some examples of control units (such as control unit 130) may include non-transitory tangible machine-readable media that include executable code that, when executed by one or more processors (e.g., processor 140), may cause the one or more processors to perform the processes of method 300. Some common forms of machine-readable media that may include the processes of method 300 are, for example, floppy disks, diskettes, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tapes, any other physical media with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, and / or any other media from which a processor or computer is suitable for reading.

[0047] Although illustrative embodiments have been shown and described, extensive modifications, variations, and substitutions are contemplated in the foregoing disclosure, and in some cases, some features of the embodiments may be employed without corresponding use of other features. Those of ordinary skill in the art will recognize many variations, substitutions, and modifications. Therefore, the scope of the present invention should be limited only by the appended claims, which are interpreted broadly and in a manner consistent with the scope of the embodiments disclosed herein as appropriate.

Claims

1. A computer-assisted medical device, comprising: an articulated arm including a first joint; as well as a control unit coupled to the articulated arm and comprising one or more processors; The control unit: switching the first joint from a locked state in which movement of the first joint is restricted to a floating state when an actuation associated with the first joint exceeds a first unlocking threshold, wherein movement of the first joint is restricted in the locked state and movement of the first joint is permitted in the floating state; and switching the first joint from the floating state to the locked state when a speed associated with the first joint is below a first locking threshold; in: The first unlocking threshold is determined based on a purpose of the first joint in the articulated arm; or The first locking threshold is determined based on a purpose of the first joint in the articulated arm; wherein the stimulus corresponds to: a position error of the first joint between a commanded position of the first joint and a current position of the first joint, wherein the first joint is an actuated joint; or A position error of the first joint between a detent position of the first joint and a current position of the first joint, wherein the first joint is a non-actuated joint.

2. The apparatus according to claim 1, wherein: If the first joint is in the floating state, the control unit commands the first joint of the actuating joint to a command position or commands the first joint of the actuating joint to a command speed; wherein the command position is the actual position of the first joint or a portion of the distance behind the actual position of the first joint based on the movement direction of the first joint; and The command speed of the first joint is the actual speed of the first joint or a certain value lower than the actual speed of the first joint.

3. The apparatus according to claim 1, wherein: adjusting the first unlocking threshold based on the posture, position or orientation of the articulated arm; or The first locking threshold is adjusted based on a posture, position, or orientation of the articulated arm.

4. The device according to claim 1, wherein the control unit: switching the first joint from the locked state to the floating state when the excitation on the first joint has continuously exceeded the first unlocking threshold for a predetermined period of time; or switching the first joint from the locked state to the floating state when the collection of the excitation on the first joint over a predetermined time period has exceeded the first unlocking threshold of the first joint; or Prior to switching the first joint to the floating state for the first time, the first joint is maintained in the locked state for a predetermined period of time.

5. The apparatus of claim 1, wherein the first joint is a non-actuated joint and wherein: the control unit activates a brake on the first joint in the locked state; or The control unit at least partially releases the brake on the first joint in the floating state.

6. The device according to any one of claims 1 to 5, wherein the control unit: switching the first joint from the floating state to the locked state when the speed associated with the first joint, aggregated over a predetermined period of time, is below the first locking threshold; or The first joint is switched from the floating state to the locked state when the speed associated with the first joint is continuously below the first locking threshold for the predetermined period of time.

7. The apparatus according to any one of claims 1 to 5, wherein The first unlocking threshold is based on whether the first joint has passed a soft stop position; or The first locking threshold is based on whether the first joint has passed a soft stop position; or The control unit switches the first joint from the locked state to the floating state when the first joint passes a soft stop position.

8. The apparatus according to any one of claims 1 to 5, wherein the control unit prevents the first joint from switching to the floating state when the articulated arm is in a predetermined operating mode, wherein the predetermined operating mode comprises a mode selected from the group consisting of a transmission mode, a remote operation mode, a command movement mode and a docking mode with a patient.

9. A non-transitory machine-readable medium comprising a plurality of machine-readable instructions which, when executed by one or more processors associated with a medical device, are adapted to cause the one or more processors to perform a method comprising: When an excitation associated with a first joint of an articulated arm of the medical device exceeds a first unlocking threshold, switching the first joint from a locked state in which movement of the first joint is restricted to a floating state and permitting movement of the first joint in the floating state; and switching the first joint from the floating state to the locked state when a speed associated with the first joint is below a first locking threshold; in: The first unlocking threshold is determined based on a purpose of the first joint in the articulated arm; or The first locking threshold is determined based on a purpose of the first joint in the articulated arm; wherein the stimulus corresponds to: a position error of the first joint between a commanded position of the first joint and a current position of the first joint, wherein the first joint is an actuated joint; or A position error of the first joint between a detent position of the first joint and a current position of the first joint, wherein the first joint is a non-actuated joint.

10. The non-transitory machine-readable medium of claim 9, wherein adjusting the first unlocking threshold based on the posture, position or orientation of the articulated arm; or The first locking threshold is adjusted based on a posture, position, or orientation of the articulated arm.

11. The non-transitory machine-readable medium of claim 9 or 10, wherein the method further comprises: switching the first joint from the locked state to the floating state when the excitation on the first joint has continuously exceeded the first unlocking threshold for a predetermined period of time; or switching the first joint from the locked state to the floating state when the collection of the excitation on the first joint over a predetermined time period has exceeded the first unlocking threshold of the first joint; or Prior to switching the first joint to the floating state for the first time, the first joint is maintained in the locked state for a predetermined period of time.

12. The non-transitory machine-readable medium of claim 9 or 10, wherein the method further comprises: switching the first joint from the floating state to the locked state when the speed associated with the first joint, aggregated over a predetermined period of time, is below the first locking threshold; or The first joint is switched from the floating state to the locked state when the speed associated with the first joint is continuously below the first locking threshold for the predetermined period of time.

13. A computer-assisted medical device, comprising: an articulated arm including a first joint; as well as a control unit coupled to the articulated arm and comprising one or more processors, The control unit: switching the first joint from a locked state in which movement of the first joint is restricted to a floating state when an actuation associated with the first joint exceeds a first unlocking threshold, wherein movement of the first joint is restricted in the locked state and movement of the first joint is permitted in the floating state; switching the first joint from the floating state to the locked state when a speed associated with the first joint is below a first locking threshold; and The first joint is prevented from switching from the locked state to the floating state when the articulated arm is in a predetermined operating mode, wherein the predetermined operating mode comprises a mode selected from the group consisting of a transmission mode, a remote operation mode, and a command motion mode.

14. The apparatus of claim 13, wherein: If the first joint is in the floating state, the control unit commands the first joint of the actuating joint to a command position or commands the first joint of the actuating joint to a command speed; The command position is the actual position of the first joint or a portion of the distance behind the actual position of the first joint based on the direction of movement of the first joint; and The command speed of the first joint is an actual speed of the first joint or a certain value lower than the actual speed of the first joint.

15. The apparatus according to claim 13, wherein adjusting the first unlocking threshold based on the posture, position or orientation of the articulated arm; or The first locking threshold is adjusted based on a posture, position, or orientation of the articulated arm.

16. The apparatus of claim 13, wherein the control unit: switching the first joint from the locked state to the floating state when the excitation on the first joint has continuously exceeded the first unlocking threshold for a predetermined period of time; or switching the first joint from the locked state to the floating state when the collection of the excitation on the first joint over a predetermined time period has exceeded the first unlocking threshold of the first joint; or Prior to switching the first joint to the floating state for the first time, the first joint is maintained in the locked state for a predetermined period of time.

17. The apparatus according to any one of claims 13 to 16, wherein the control unit: switching the first joint from the floating state to the locked state when the speed associated with the first joint, aggregated over a predetermined period of time, is below the first locking threshold; or The first joint is switched from the floating state to the locked state when the speed associated with the first joint is continuously below the first locking threshold for the predetermined period of time.

18. The apparatus of any one of claims 13 to 16, wherein the stimulus corresponds to: a position error of the first joint between a commanded position of the first joint and a current position of the first joint, wherein the first joint is an actuated joint; or a position error of the first joint between a braking position of the first joint and a current position of the first joint, wherein the first joint is a non-actuated joint; or The force or torque on the first joint.

19. A non-transitory machine-readable medium comprising a plurality of machine-readable instructions which, when executed by one or more processors associated with a medical device, are adapted to cause the one or more processors to perform a method comprising: When an excitation associated with a first joint of an articulated arm of the medical device exceeds a first unlocking threshold, switching the first joint from a locked state in which movement of the first joint is restricted to a floating state and permitting movement of the first joint in the floating state; switching the first joint from the floating state to the locked state when a speed associated with the first joint is below a first locking threshold; and The first joint is prevented from switching from the locked state to the floating state when the articulated arm is in a predetermined operating mode, wherein the predetermined operating mode comprises a mode selected from the group consisting of a transmission mode, a remote operation mode, and a command motion mode.

20. The non-transitory machine-readable medium of claim 19, wherein: If the first joint is in the floating state and the first joint is an actuated joint, the method includes commanding the first joint of the actuated joint to a command position or commanding the first joint of the actuated joint to a command velocity; wherein the command position is the actual position of the first joint or a portion of the distance behind the actual position of the first joint based on the direction of movement of the first joint, and the command speed of the first joint is the actual speed of the first joint or a certain value lower than the actual speed of the first joint; or If the first joint is a non-actuated joint, the method further comprises activating a brake on the first joint in the locked state or at least partially releasing the brake on the first joint in the floating state.

21. The non-transitory machine-readable medium of claim 19, wherein: adjusting the first unlocking threshold based on the posture, position or orientation of the articulated arm; or The first locking threshold is adjusted based on a posture, position, or orientation of the articulated arm.

22. The non-transitory machine-readable medium of any one of claims 19 to 21, wherein the method further comprises: switching the first joint from the floating state to the locked state when the speed associated with the first joint, aggregated over a predetermined period of time, is below the first locking threshold; or The first joint is switched from the floating state to the locked state when the speed associated with the first joint is continuously below the first locking threshold for the predetermined period of time.

23. A method of controlling movement of a medical device, the method comprising: operating each of a plurality of joints of an articulated arm of the medical device in a locked state, wherein movement of the corresponding joint is restricted in the locked state; determining an excitation on a subset of joints, the plurality of joints comprising the subset of joints; When the actuation exceeds an unlocking threshold, switching a subset of the joints from the locked state to a floating state, wherein in the floating state movement of the corresponding joints is permitted; determining a velocity of each of a subset of the joints; switching a subset of the joints from the floating state to the locked state when the speed is below a locking threshold; as well as If the subset of joints is in the floating state, each command in the subset of joints will be an actuated joint to a corresponding command position or each command in the subset of joints will be an actuated joint to a corresponding command velocity; wherein the corresponding command position of a joint in the subset of joints is the actual position of the joint or a fraction of a distance behind the actual position of the joint based on the direction of motion of the joint; and The corresponding command speed of the joint is the actual speed of the joint or a certain value lower than the actual speed of the joint.

24. The method of claim 23, wherein when the actuation exceeds the unlocking threshold, switching the subset of the joints from the locked state to the floating state comprises: When the actuation of each joint of the subset of joints exceeds a respective unlocking threshold associated with that joint, the subset of joints is switched from the locked state to the floating state.

25. The method of claim 23, wherein when the speed is below the locking threshold, switching the subset of the joints from the floating state to the locked state comprises: switching the subset of joints from the floating state to the locked state when the speed of each joint of the subset of joints is below a corresponding locking threshold associated with the joint; or When the speed is continuously below the locking threshold for a predetermined period of time, a subset of the joints are switched from the floating state to the locked state.

26. The method of claim 23, further comprising switching the subset of joints from the locked state to the floating state when corresponding joints of the subset of joints pass corresponding soft stop positions.

27. The method of claim 23, further comprising switching the subset of connectors from the floating state to the locked state when corresponding connectors of the subset of connectors pass corresponding soft stop positions.

28. The method according to claim 23 further includes maintaining the subset of connectors in the locked state until the excitation on the corresponding connectors of the subset of connectors drops below the corresponding unlocking threshold for a predetermined time period before allowing the subset of connectors to switch to the floating state for the first time.

29. A computer-assisted medical device comprising: an articulated arm including a first joint; as well as a control unit coupled to the articulated arm and comprising one or more processors, The control unit: switching the first joint from a locked state to a floating state when an actuation associated with the first joint exceeds a first unlocking threshold, wherein in the locked state movement of the first joint is restricted by activating a brake on the first joint, and in the floating state movement of the first joint is permitted by at least partially releasing the brake on the first joint; switching the first joint from the floating state to the locked state when a speed associated with the first joint is below a first locking threshold; as well as The first joint is prevented from switching from the locked state to the floating state when the articulated arm is in a predetermined operating mode, wherein the predetermined operating mode comprises a mode selected from the group consisting of a transmission mode, a remote operation mode, and a command motion mode.

30. The computer-assisted medical device of claim 29, wherein: adjusting the first unlock threshold based on a posture, position, or orientation of the articulated arm; or The first locking threshold is adjusted based on a posture, position, or orientation of the articulated arm.

31. The computer-assisted medical device of claim 29, wherein the control unit: switching the first joint from the locked state to the floating state when the excitation on the first joint has continuously exceeded the first unlocking threshold for a predetermined period of time; or switching the first joint from the locked state to the floating state when the collection of the excitation on the first joint over a predetermined time period has exceeded the first unlocking threshold of the first joint; or Prior to switching the first joint to the floating state for the first time, the first joint is maintained in the locked state for a predetermined period of time.

32. The computer-assisted medical device according to any one of claims 29 to 31, wherein the control unit: switching the first joint from the floating state to the locked state when the speed associated with the first joint, aggregated over a predetermined period of time, is below the first locking threshold; or The first joint is switched from the floating state to the locked state when the speed associated with the first joint is continuously below the first locking threshold for the predetermined period of time.

33. A computer assisted medical device according to any one of claims 29 to 31, wherein the stimulus corresponds to: a position error of the first joint between a commanded position of the first joint and a current position of the first joint, wherein the first joint is an actuated joint; or a position error of the first joint between a braking position of the first joint and a current position of the first joint, wherein the first joint is a non-actuated joint; or The force or torque on the first joint.

34. A non-transitory machine-readable medium comprising a plurality of machine-readable instructions which, when executed by one or more processors associated with a medical device, are adapted to cause the one or more processors to perform a method comprising: When an excitation associated with a first joint of an articulated arm of the medical device exceeds a first unlocking threshold, switching the first joint from a locked state, wherein in the locked state movement of the first joint is restricted by activating a brake on the first joint, to a floating state, and in the floating state movement of the first joint is permitted by at least partially releasing the brake on the first joint; switching the first joint from the floating state to the locked state when a speed associated with the first joint is below a first locking threshold; as well as The first joint is prevented from switching from the locked state to the floating state when the articulated arm is in a predetermined operating mode, wherein the predetermined operating mode comprises a mode selected from the group consisting of a transmission mode, a remote operation mode, and a command motion mode.

35. The non-transitory machine-readable medium of claim 34, wherein: adjusting the first unlocking threshold based on the posture, position or orientation of the articulated arm; or The first locking threshold is adjusted based on a posture, position, or orientation of the articulated arm.

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