Console for controlling a robot manipulator

Abstract

Console (202) for controlling a robot manipulator with an end effector (207), the console (202) comprising: a hand controller (301) connected to a gimbal assembly (303); and an articulated linkage (304) connected at its proximal end to a rigid support structure (302) and at its distal end to the gimbal assembly (303); wherein the gimbal assembly (303) comprises only three degrees of freedom provided by only three joints (401, 402, 403), wherein a first joint (401) of the three joints (401, 402, 403) allows the gimbal assembly (303) to rotate about a first axis (404) with respect to the distal end of the joint linkage (304); and characterized in that the linkage (304) and the gimbal assembly (303) are arranged such that in each configuration of the linkage (304) and the gimbal assembly (304), the first axis (404) has the same orientation with respect to the support structure (302), wherein the linkage (304) has a parallelogram profile, whereby the first axis (404) is mechanically constrained to have the same orientation with respect to the support structure (302) in each configuration of the linkage (304); and wherein the bracket (202) is configured such that, when the bracket (202) is disposed on a horizontal surface, the first axis (404) is vertical in each configuration of the linkage (304) and the gimbal assembly (303).

Description

FIELD OF THE INVENTION

[0001] The invention relates to consoles for controlling robot systems such as master-slave manipulators. BACKGROUND

[0002] Master-slave manipulators typically comprise a slave device for performing an action and a master device that is directly manipulated by a user. The master device and the slave device are operatively linked such that user manipulation of the master device causes the slave device to perform a corresponding action. Master-slave manipulators are common in many technical fields, such as surgical robotics, where a surgeon manipulates hand controls at a console to cause a surgical robot to perform an operation.

[0003] Fig. Figure 1 illustrates a known controller for a master-slave manipulator with an end effector comprising a pair of movable jaws. The controller has a primary input shaft 101. The primary input shaft forms the distal end of a gimbal assembly 102. The proximal end of the gimbal assembly is attached to a support structure of a console via a linkage, a portion of which is shown at 103. The primary input shaft is provided with two rotatable elements 104, 105 that can be connected to a user's fingers by loops 106. The user can move the primary input shaft 101 to command a change in the position of the end effector and can move the elements 104, 105 to command opening or closing of the end effector's jaws. The gimbal assembly 102 has four rotational degrees of freedom.This allows the gimbal assembly to accommodate movement of the primary input shaft in three rotational degrees of freedom with kinematic redundancy. Using the redundant joint allows the gimbal assembly to avoid the kinematic singularity that would otherwise arise if movement of the primary input shaft caused two of the gimbal assembly's rotational axes to become aligned. This controller is relatively large, which can be problematic if the controller's workspace is limited. This problem is further exacerbated when the user manipulates two such controllers, one in each hand, within a shared workspace. SUMMARY OF THE INVENTION

[0004] According to a first aspect, a console for controlling a robot manipulator with an end effector is provided, the console comprising: a hand controller connected to a gimbal assembly; and an articulated linkage connected at its proximal end to a rigid support structure and at its distal end to the gimbal assembly; wherein the gimbal assembly comprises only three degrees of freedom provided by only three joints, a first joint of the three joints of the gimbal assembly allowing rotation about a first axis with respect to the distal end of the articulated linkage; and wherein the articulated linkage and the gimbal assembly are arranged such that, in each configuration of the articulated linkage and the gimbal assembly, the first axis has the same orientation with respect to the support structure.

[0005] The bracket may be configured such that, when the bracket is disposed on a horizontal surface, the first axis is vertical in any configuration of the linkage and gimbal assembly.

[0006] The console may be configured to fully accommodate rotation of the hand controller by articulating the three joints of the gimbal assembly.

[0007] The console may be designed to accommodate a displacement of the hand control by articulating the joint linkage.

[0008] The gimbal assembly may include: a first link and a second link; a second joint allowing the first link to rotate relative to the second link about a second axis, the second axis being perpendicular to the first axis; and a third joint allowing the hand controller to rotate relative to the second link about a third axis, the third axis being perpendicular to the second axis.

[0009] From a central position of the gimbal assembly in which the first axis, the second axis and the third axis are all perpendicular to each other, the range of motion of the first joint may be limited such that it is capable of rotating more than 90° in any direction of rotation about the first axis.

[0010] From the central position of the gimbal assembly, the first joint may be limited to a maximum angle of rotation between 90° and 115° in one direction of rotation, causing the first link to move toward the distal end of the joint linkage.

[0011] From the central position of the gimbal assembly, the first joint may be limited to a maximum angle of rotation between 90° and 100° in one direction of rotation, causing the first linkage to move away from the distal end of the joint linkage.

[0012] From a central position of the gimbal assembly in which the first axis, the second axis and the third axis are all perpendicular to each other, the range of motion of the second joint may be limited such that it is capable of rotating less than 90° in any direction of rotation about the second axis.

[0013] From the central position of the gimbal assembly, the second joint may be limited to a maximum angle of rotation between 80° and 90° in one direction of rotation, causing the second joint to move toward the first connection.

[0014] From the central position of the gimbal assembly, the second joint may be limited to a maximum angle of rotation between 80° and 90° in one direction of rotation, causing the second connection to move away from the first connection.

[0015] From a central position of the gimbal assembly in which the first axis, the second axis, and the third axis are all perpendicular to each other, the range of motion of the third joint may be limited such that it is capable of rotating less than or equal to 90° about the third axis in any direction of rotation.

[0016] From the central position of the gimbal assembly, the third joint can be limited to a maximum angle of rotation of 90° in both directions of rotation about the third axis.

[0017] The linkage may have a parallelogram profile, whereby the first axis is mechanically constrained to have the same orientation with respect to the support structure in each configuration of the linkage.

[0018] The console may further comprise a position sensor disposed at the first joint to measure a yaw movement of the hand controller solely by detecting a rotation of the first joint about the first axis.

[0019] The console may further comprise a position sensor disposed on the second joint to measure a tilt movement of the hand controller solely by detecting a rotation of the second joint about the second axis.

[0020] The console may further comprise a position sensor disposed at the third joint to measure a rolling motion of the hand controller solely by detecting a rotation of the third joint about the third axis.

[0021] The console may be a surgeon console for controlling a surgical robot carrying a surgical instrument.

[0022] The console can further control a further robot manipulator with a further end effector. The console can further comprise: a further hand controller connected to a further gimbal assembly; and a further joint linkage connected at its proximal end to the rigid support structure and at its distal end to the further gimbal assembly; wherein the further gimbal assembly comprises only three degrees of freedom provided by only three joints, wherein a first joint of the three joints allows the further gimbal assembly to rotate about a fourth axis with respect to the distal end of the further joint linkage; and wherein the further joint linkage and the further gimbal assembly are arranged such that, in each configuration of the further joint linkage and the further gimbal assembly, the fourth axis has the same orientation with respect to the support structure.

[0023] The hand control may be configured for operation by one hand of a user, and the further hand control may be configured for operation by the other hand of the user. SHORT DESCRIPTION OF THE CHARACTERS

[0024] The present invention will now be described by way of example with reference to the accompanying drawings. In the drawings: Fig. 1 a known control for a master-slave manipulator; Fig. 2 a master-slave manipulator; Fig. 3 an input device of a console for controlling a robot manipulator; and Fig. 4 a hand control and gimbal assembly of a console. DETAILED DESCRIPTION

[0025] Fig. Figure 2 schematically illustrates the general layout of a master-slave manipulator, wherein a robot, generally indicated at 201, is controlled by a console, generally indicated at 202. The robot 202 includes a robot arm 203 extending from a base 204. The robot arm is articulated by a series of pivot joints 205 along its length. The distal end of the robot arm 203 is connected to an instrument 206. The instrument 206 terminates in an end effector 207. In this example, the end effector has a pair of opposed jaws. These can be moved relative to each other to grasp or cut objects located between the jaws. The end effector is driven to move by a motor 208 at the distal end of the robot arm. The motor 208 is connected to the end effector by cables extending along the inside of the instrument shaft.The joints of the robot arm are driven by motors 209. These motors can be distributed along the arm. Each motor can be located proximal to the joint it drives. Position sensors and force / torque sensors 210 can be arranged on the robot arm to detect the position of the joints and the forces / torques acting on the joints 205.

[0026] The console 202 includes an input device 211 that is manipulated by a user to effect manipulation of the robot arm 203 and the instrument 206. The console may also include a second input device 212. One input device may be configured for operation by one hand of a user for manipulation of one robot arm, and the other input device may be configured for operation by the user's other hand for manipulation of another robot arm. The console may further include a display screen 213 to allow the user to view the manipulation performed by the instrument 206.

[0027] The control unit 214 controls the robot arm 203 in response to control inputs. The control unit 214 receives control inputs from the input device 211. The control unit 214 may also receive control inputs from other sources, such as position sensors and force / torque sensors 210. The control unit 214 includes a processor 215 that executes code stored in non-volatile form in a memory 216. Upon executing the code, the processor 215 determines a set of signals for controlling the movement of the robot's joints and for moving the instrument's end effector 207 in response to the inputs from the input device 211 and the robot arm's position / force sensors 210. The control unit 214 may be located on the console 202, on the robot arm 203, or elsewhere in the system.

[0028] The Fig. The master-slave manipulator illustrated in Figure 2 may, for example, be a surgical robot system. In this example, console 202 is a surgeon's console, and robot 201 is a surgical robot carrying a surgical instrument 206 for performing a surgery. The surgery may be minimally invasive. In this case, the surgeon may view the video feed from an endoscope depicting the surgical site on display screen 213.

[0029] Fig. 3 illustrates an exemplary input device 211 of Fig. 2 in more detail. The input device 211 includes a hand controller 301 connected to a rigid support structure 302 of the console via a series of articulated joints. This series of articulated joints includes a gimbal assembly 303 and an articulated linkage 304. The hand controller 301 is directly connected to the gimbal assembly 303. The gimbal assembly 303 is connected at its distal end to the hand controller 301 and at its proximal end to the articulated linkage 304. The articulated linkage 304 is connected at its distal end to the gimbal assembly 303 and at its proximal end to the support structure 302.

[0030] The gimbal assembly is in Fig. 4 in more detail. The gimbal assembly includes only three degrees of freedom. These three degrees of freedom are orientations. The three degrees of freedom are provided by three joints: a first joint 401, a second joint 402, and a third joint 403. Each of these three joints is a rotary joint. The first joint 401 connects the end linkage 304 to a first linkage 407 of the gimbal assembly. The first joint 401 allows the first linkage 407 of the gimbal assembly to rotate about a first axis 404 with respect to the end link 409 of the gimbal linkage 304. The second joint 402 connects the first linkage 407 of the gimbal assembly to a second linkage 408 of the gimbal assembly. The second joint 402 allows the second connection 408 of the gimbal assembly to rotate about a second axis 405 with respect to the first connection 407 of the gimbal assembly.The second axis 405 is perpendicular to the first axis 404. The third joint 403 connects the second connection 408 of the gimbal assembly to the hand controller 301. The third joint 403 enables the hand controller 301 to rotate about a third axis 406 relative to the second connection 408 of the gimbal assembly. The third axis 406 is perpendicular to the second axis 405.

[0031] The first connection 407 may be formed from a first portion 407a and a second portion 407b. The first portion 407a is connected to the first joint 401. The second portion 407b is connected to the second joint 402. The first portion 407a and the second portion 407b are rigidly connected to each other. The first portion 407a and the second portion 407b may not be aligned. For example, as in Fig. 4, the longitudinal axis 410a of the first section 407a may be transverse to the longitudinal axis 410b of the second section 407b. The axes 410a and 410b may be perpendicular to each other. Thus, the first connection 407 as a whole forms an L-shape.

[0032] Similarly, the second connection 408 may be formed from a first portion 408a and a second portion 408b. The first portion 408a is connected to the second joint 402. The second portion 408b is connected to the third joint 403. The first portion 408a and the second portion 408b are rigidly connected to each other. The first portion 408a and the second portion 408b may not be aligned. For example, as in Fig. 4, the longitudinal axis 411a of the first section 408a may be transverse to the longitudinal axis 411b of the second section 408b. The axes 411a and 411b may be perpendicular to each other. Thus, the second connection 408 as a whole forms an L-shape.

[0033] The linkage 304 and the gimbal assembly 303 are arranged such that, in each configuration of the linkage and the gimbal assembly, the first axis 404 has the same orientation with respect to the support structure 302. For example, when the console is arranged on a horizontal surface, the first axis is vertical in each configuration of the linkage and the gimbal assembly. The linkage may be mechanically constrained to cause the first axis 404 to maintain the same orientation with respect to the support structure. Fig. Figure 3 illustrates a specific example.

[0034] In Fig. 3, the articulated linkage comprises a parallelogram mechanism. This parallelogram mechanism includes a first parallelogram 4-bar chain 305 and a second parallelogram 4-bar chain 306. The first parallelogram 4-bar chain 305 includes links 305a, 305b, 305c, and 305d, which connect the joints 311a, 311b, 311c, and 311d. The links 305a and 305c are of equal length and parallel. The links 305b and 305d are of equal length and parallel. Each of the joints 311a, 311b, 311c, and 311d is a rotary joint. The rotation axes of the joints 311a, 311b, 311c, and 311d are parallel.

[0035] The second parallelogram 4-bar chain 306 includes links 306a, 306b, 306c, and 306d, which connect joints 312a, 312b, 312c, and 311d. Links 306b and 306d are of equal length and parallel. Links 306a and 306c are of equal length and parallel. Each of joints 312a, 312b, 312c, and 311d is a pivot joint. The pivot axes of joints 312a, 312b, 312c, and 311d are parallel.

[0036] Thus, the rotation axes of all joints 311a, 311b, 311c, 311d, 312a, 312b, and 312c are parallel. Thus, the parallelogram mechanism as a whole is planar.

[0037] The entire parallelogram mechanism rotates about the axis 308. The axis 308 can be perpendicular to the rotation axes of the joints. The angle Φ between the connection 305a and the axis 308 is fixed. The connection 305a can rotate about the axis 308. When the support structure 302 is on a horizontal surface, the axis 308 is correspondingly vertical. Fig. 3, connection 305a is connected to the support structure 302 via connection 310. The longitudinal axis of connection 310 is axis 308.

[0038] The two parallelogram 4-bar chains 305 and 306 are connected by a triangular fixed link 307. This triangular fixed link 307 includes links 305c and 306d. The angle θ between link 305c and link 306d remains constant. Thus, the orientation of link 306d with respect to link 305a is fixed. Thus, the orientation of link 306b with respect to link 305a is fixed.

[0039] The axis 309 is perpendicular to the rotational axes of the joints of the parallelogram mechanism. The axis 309 intersects the connection 306b. The angle Ψ between the connection 306b and the axis 309 is fixed. Thus, the axis 308 is kept parallel to the axis 309. Fig. 3, the connection 306b is connected to the gimbal assembly 303 via a connection 313. The longitudinal axis of the connection 313 is axis 309. In Fig. 3, the linkage 313 is connected to the gimbal assembly 303 via the end connection of the linkage 409. The linkage 409 is connected at one end to the linkage 313 and at the other end to the gimbal assembly 303.

[0040] In an alternative arrangement, the gimbal assembly 303 may be directly connected to the link 313.

[0041] The linkage is thereby mechanically constrained to maintain the same alignment between link 305a at one end of the parallelogram mechanism and link 306b at the other end of the parallelogram mechanism. However, the parallelogram mechanism allows movement of link 306b relative to link 305a parallel to axis 308 and perpendicular to axis 308, thereby accommodating corresponding movement of the hand controller. In the event that the mounting structure 302 is located on a horizontal surface, the parallelogram mechanism allows vertical and horizontal movement of the hand controller to be accommodated. Since the parallelogram mechanism can rotate about axis 308 relative to the support structure 302, the linkage accommodates all three translational degrees of freedom.

[0042] The linkage is constrained to cause axes 308 and 309 to be maintained parallel, while the linkage can be moved to cause axes 308 and 309 to move away from each other. In each configuration of the linkage, the first axis 404 has the same orientation with respect to the support structure 302. Accordingly, the support structure, linkage, and gimbal assembly are configured such that, when the console is disposed on a horizontal surface, the first axis 404 is always vertical in each configuration of the linkage and gimbal assembly.

[0043] Optionally, the articulated linkage also includes an additional linkage 314. Linkage 314 includes links 314a, 314b, and 314c. Linkage 314 forms a parallelogram with linkage 305d. Linkage 314a is connected to linkage 306c and linkage 305d via joint 311d. Linkage 314a is connected to linkage 314b via joint 315b. Links 314a and 306c can be a single linear rod. In this case, linkage 306c is fixed with respect to linkage 314a. That is, linkage 306c is fixed with respect to linkage 314a. Linkage 314b is connected to linkage 314c via joint 315a. The connection 314c is connected to the connection 305d and the connection 305a via the joint 311a.Accordingly, joints 315a and 315b are both rotary joints with axes of rotation parallel to the axes of rotation of the other joints 311a, 311b, 311c, 311d, 312a, 312b, and 312c of the parallelogram mechanism. Links 314a and 314c are of equal length and parallel. Links 305b and 314d are of equal length and parallel. Thus, links 305b, 305d, and 314b are all parallel. Link 314c can rotate relative to link 305a.

[0044] As explained below, the articulated linkage 304 may be driven. To achieve this, at least one joint of the first 4-bar parallelogram chain 305 is driven, and at least one joint of the second 4-bar parallelogram chain is driven. Accordingly, in the first 4-bar parallelogram chain 305, either joint 311a or joint 311b is driven. Driving this individual joint causes movement of the entire 4-bar parallelogram chain 305. An actuator on the driven joint drives rotation of the joint about its axis. The actuator and joint controller for the driven joint are arranged near this joint and thus near the axis 308 and the support structure 302.

[0045] The second parallelogram 4-bar chain 306 could be driven by actuating one of the joints 312a, 312b, 312c, or 311d. These joints are all located distally of the support structure 302. An actuator for driving the joint would be arranged at this joint. This actuator would respond to the actuator used to drive the driven joint of the first parallelogram 4-bar chain 305. This would require the actuator of the first parallelogram 4-bar chain 305 to be larger and thus heavier.

[0046] The additional linkage 314 enables the second parallelogram 4-bar chain 306 to be driven more efficiently. More specifically, either joint 315a or joint 311a is driven. Driving this individual joint causes movement of joint 314 and thus movement of link 306c and thus movement of the entire second parallelogram 4-bar chain 306. An actuator on the driven joint 315a or 311a drives rotation of this joint about its axis. The actuator and joint control for the driven joint are located near this joint and thus near the axis 308 and the support structure 302.

[0047] Thus, the additional linkage 314 enables an overall lighter design of the articulated linkage 304, since the actuators and the associated drive electronics for driving the articulated linkage can be arranged more efficiently.

[0048] Rotation of the hand controller is entirely accommodated by articulating the joints of the gimbal assembly. A force applied as a roll motion to the hand controller is accommodated by rotating the hand controller 301 relative to the second link 408 about the third axis 406. A force applied as a pitch motion to the hand controller is accommodated by rotating the second link 408 relative to the first link 407 about the second axis 405. A force applied as a yaw motion to the hand controller is accommodated by rotating the first link 407 relative to the end link 409 of the articulated linkage about the first axis 404. The first axis 404, maintained in the same orientation with respect to the support structure 302, prevents rotation of the hand controller from being transmitted to, and thus accommodated by, the articulated linkage 304.

[0049] The gimbal assembly may include a position sensor 416 disposed on the first joint 401 to detect rotation of the first joint 401 about the first axis 404. The gimbal assembly may include a position sensor 417 disposed on the second joint 402 to detect rotation of the second joint 402 about the second axis 405. The gimbal assembly may include a position sensor 418 to detect rotation of the third joint 403 about the third axis 406. Each position sensor 416, 417, 418 may be configured to transmit its detected position data to the control unit 214. The control unit 214 may use the received position data to determine the configuration of the gimbal assembly and thus the rotational position (i.e., posture / attitude) of the hand controller.In particular, the control unit 214 can determine: (i) the yaw movement of the hand controller 301 exclusively based on the detected position data of the position sensor 416 arranged at the first joint 401 and / or (ii) the pitch movement of the hand controller 301 exclusively based on the detected position data of the position sensor 417 arranged at the second joint 402 and / or (iii) the roll movement of the hand controller 301 exclusively based on the detected position data of the position sensor 418 arranged at the third joint 403.

[0050] The three degrees of freedom of the gimbal assembly are decoupled around the three joints of the gimbal assembly. That is, at any point in the working range of the hand controller: (i) the first axis 404 lies in the same direction (e.g., vertical) and exclusively accommodates the yaw movement of the hand controller, (ii) the second axis 405 lies in the same plane (e.g., horizontal) and exclusively accommodates the pitch movement of the hand controller, and (iii) the third axis 406 lies in the same plane (e.g., horizontal) and exclusively accommodates the roll movement of the hand controller. This allows yaw movement of the hand controller to be measured using only the position sensor 416 at the first joint 401. Similarly, this allows pitch movement of the hand controller to be measured using only the position sensor 417 at the second joint 402.Similarly, this allows roll movement of the hand controller to be measured using only the position sensor 418 at the third joint 403. In a four-degree-of-freedom gimbal assembly, sensing a composite of yaw, pitch, and roll movement of the hand controller requires measurements from a plurality of sensors. Therefore, the gimbal assembly described herein allows the control unit to perform a computationally more efficient calculation to determine the configuration of the gimbal assembly.

[0051] Displacement of the hand controller is accommodated by articulating the joints of the linkage 304. A force applied to the hand controller to displace the hand controller directly toward the support structure 302 or parallel to the axis 308 is accommodated by rotating the joints of the parallelogram mechanism about their axes. A force applied to the hand controller to displace the hand controller in a direction transverse to the direction of the support structure 302 is accommodated by rotating the linkage about the axis 308. It is also accommodated by a small rotation of the gimbal assembly about the first axis 404 to maintain the orientation of the gimbal assembly.

[0052] The articulated linkage 304 may include a position sensor 314 arranged at each joint to detect rotation of that joint about its axis. Each position sensor 314 may be configured to transmit its detected position data to the control unit 214. The control unit 214 may use the received position data to determine the configuration of the articulated linkage and thus the displacement position of the hand controller. In particular, the control unit 214 may use the position data received from the sensors 314 and the dimensions of the articulated linkage 304 and the gimbal assembly 303 to determine the position of the hand controller 301 within the work area in which the hand controller 301 is permitted to move.

[0053] Any composite motion resulting from the forces applied to the hand controller can be decomposed into the six force components described above: roll, pitch, and yaw motions of the hand controller, and translation in three perpendicular directions. Each of these force components is recorded and captured as described above.

[0054] By decoupling the joints that accommodate rotational movement of the hand controller (i.e., the gimbal assembly) from the joints that accommodate translational movement of the hand controller (i.e., the articulated linkage), the user-perceived correspondence between the direction of rotation and movement of the hand controller and that of the end effector (as displayed on the console screen) is independent of the position of the hand controller within the hand controller's working envelope.

[0055] The Fig. The arrangement of the articulated linkage shown in Figure 3 is an example. The articulated linkage may include alternative or additional connections and joints while still being mechanically constrained to cause the first axis 404 to maintain its orientation relative to the support structure. For example, instead of the parallelogram mechanism described above, the articulated linkage may include a scissor-arm mechanism mounted on a pivot axis, a Sarrus linkage mechanism mounted on a pivot axis, or a combination of a scissor-arm mechanism and a Sarrus linkage mechanism.

[0056] The hand control 301 includes several inputs. Fig. For example, Figure 4 illustrates push buttons 412a, 412b, 412c and joystick 413. The hand controller 301 may also include an input lever or trigger 414. The user may push the input lever 414 toward the body 415 of the hand controller 301. Other example inputs include rotary knobs and rocker switches.

[0057] As mentioned above, the control unit 214 controls the robot arm 203 in response to control inputs from the input device 211 and optionally additionally from other sources such as position sensors and / or force / torque sensors on the robot arm. The control inputs from the input device 211 may include: (i) control inputs from the inputs on the hand controller, e.g., button presses, movement of the input lever, and / or (ii) control inputs from the gimbal assembly resulting from rotation of the hand controller, and / or (iii) control inputs from the wrist linkage resulting from translation of the hand controller.

[0058] The code executed by the processor 215 of the control unit 214 is configured so that the movement of the robot is determined primarily by the inputs from the input device 211. For example, in a normal operating mode: (i) the attitude of the end effector 207 can be adjusted by the position of the hand controller about its rotational degrees of freedom, as determined by the control inputs from the gimbal assembly; (ii) the position of the end effector 207 can be adjusted by the position of the hand controller about its translational degrees of freedom, as determined by the control inputs from the wrist linkage; and (iii) the configuration of the jaws of the end effector 207 can be adjusted by the position of the input lever 414 relative to the body 415 of the hand controller.

[0059] The Fig. The gimbal assembly illustrated in Figure 4 has only three degrees of freedom to control movement in three dimensions. This allows the gimbal assembly to be smaller and lighter than those with a redundant degree of freedom, i.e., with a total of four degrees of freedom. However, a redundant degree of freedom is useful to prevent the gimbal assembly from reaching a kinematic singularity. A kinematic singularity occurs when the gimbal assembly assumes a configuration that makes it impossible to rotate in a particular direction. For a gimbal assembly with only three degrees of freedom, this can occur when two axes of the gimbal assembly are aligned with each other. For example, in Fig. 4, when the second link 408 is rotated 90° about the second axis 405, the first axis 404 is aligned with the third axis 405. In this embodiment, the hand controller can only be rotated about two axes, not three. A four-degree-of-freedom gimbal assembly avoids this problem by providing a redundant degree of freedom. Thus, the hand controller can still be rotated about three axes even when two axes are aligned.

[0060] The range of motion of the individual joints of the gimbal assembly may be limited to prevent the gimbal assembly from assuming a configuration that results in a kinematic singularity. The limitations of the range of motion of the individual joints of the gimbal assembly will now be described with reference to a central position of the gimbal assembly. Fig. Figure 4 illustrates a gimbal assembly in the central position. In this central position, the first axis 404, the second axis 405, and the third axis 406 are all perpendicular to each other. In the central position, a longitudinal axis 419 of the end connection 409 of the linkage may be parallel to the third axis 406. In the central position, the third joint 403 may be in the middle of its range of motion.

[0061] From the central position, the range of motion of the first joint 401 can be limited such that it is capable of rotating more than 90° in any rotational direction about the first axis 404. From the central position, the maximum rotation angle of the first joint 401 can be between 90° and 125° in any rotational direction, causing the first link 407 to move toward the distal end 409 of the linkage. Preferably, the maximum rotation angle of the first joint in this rotational direction is between 90° and 115°. The maximum rotation angle of the first joint 401 can be 115° in this rotational direction. From the central position, the maximum rotation angle of the first joint 401 can be between 90° and 110° in any rotational direction, causing the first link 407 to move away from the distal end 409 of the linkage. Preferably, the maximum angle of rotation of the first joint in this direction of rotation is between 90° and 100°.The maximum angle of rotation of the first joint 401 can be 100° in this direction of rotation.

[0062] Accordingly, the range of motion of the first joint 401 about the first axis 404 is increased beyond 90° in both directions of rotation to accommodate the change in the orientation of the joint linkage 304 when the hand controller undergoes a translational movement. In this way, the angular range of motion of the gimbal assembly is not affected by the arrangement of the gimbal assembly within the working range of the hand controller.

[0063] From the central position, the range of motion of the second joint 402 may be limited such that it is capable of rotating less than 90° in any direction of rotation about the second axis 405. From the central position, the maximum angle of rotation of the second joint 402 may be between 70° and 90° in any direction of rotation, causing the second link 408 to move toward the first link 407. Preferably, the maximum angle of rotation of the second joint in this direction of rotation is between 80° and 90°. The maximum angle of rotation of the second joint 402 may be 80° in this direction of rotation. From the central position, the maximum angle of rotation of the second joint 402 may be between 70° and 90° in any direction of rotation, causing the second link 408 to move away from the first link 407. Preferably, the maximum angle of rotation of the second joint in this direction of rotation is between 80° and 90°.The maximum angle of rotation of the second joint 402 can be 80° in this direction of rotation.

[0064] Accordingly, the range of motion of the second joint 402 about the second axis 405 is limited to less than 90° in both directions of rotation in order to prevent the first axis 404 and the third axis 406 from aligning (which would be the case with a rotation angle of 90° about the second axis 405) and thereby causing a kinematic singularity.

[0065] From the central position, the range of motion of the third joint 403 can be limited such that it is capable of rotating less than or equal to 90° in both directions of rotation about the third axis 406. From the central position, the maximum angle of rotation of the third joint 403 can be between 80° and 90° in one direction of rotation, causing the hand controller 301 to move toward the second link 408. Preferably, the maximum angle of rotation of the third joint in this direction of rotation is 90°. From the central position, the maximum angle of rotation of the third joint 403 can be between 80° and 90° in one direction of rotation, causing the hand controller 301 to move away from the second link 408. Preferably, the maximum angle of rotation of the third joint in this direction of rotation is 90°.

[0066] Although the joint limitations described above limit the range of motion of the joints, this movement is still sufficient to accommodate the full range of motion of the human wrist. Because the hand controller 301 is operated by a human hand, the user experiences no limitation of the available range of motion, as they reach the limit of their hand's range of motion before reaching the limit of the range of motion of any joint of the gimbal assembly.

[0067] In addition to the range of motion limitations described above, constraining the first axis 404 to the same orientation with respect to the support structure 302 (e.g., vertical) ensures that the user is able to rotate the hand controller in both directions about each of the first, second, and third axes. If the first axis 404 were not constrained in this manner, in some embodiments of the articulating linkage 304, the gimbal assembly would be closer to a joint constraint from its central position in one direction of rotation about one axis than in the opposite direction of rotation, causing the range of motion to be more constrained in one direction of rotation than in the opposite direction of rotation about the axis.

[0068] Fig. 4 illustrates a hand controller for manipulation by a user's right hand. The console may instead or additionally include a hand controller (and associated gimbal assembly and linkage) for manipulation by a user's left hand. The hand controller, gimbal assembly, and linkage for a user's left hand would be a mirror image of the arrangement described above with respect to a user's right hand. In the event that the console includes two hand controllers (and associated gimbal assemblies and linkages), one hand controller for manipulation by a user's right hand may control manipulation of a first robotic arm and instrument via the control unit 214, and the other hand controller for manipulation by a user's left hand may control manipulation of a second robotic arm and instrument via the control unit 214.

[0069] The gimbal assembly described here is smaller and lighter than the one in Fig. 1. This allows for easier handling and greater flexibility in operation, especially when two hand controllers are manipulated by the user in the same workspace. For example, a user manipulating two hand controllers as described herein in the same workspace may cross their hands in the workspace (due to the compact design of the associated gimbal assemblies and linkages), which is not possible with the Fig. 1 is not possible.

[0070] In the device described herein, the gimbal assembly 303 and the joint linkage 304 are directly articulated by the force applied by a user to the hand controller 301. The joints of the joint linkage 304 and / or the joints of the gimbal assembly 303 may additionally be driven. The joints may be driven to: (i) compensate for the force of gravity acting on the joints and / or (ii) cause the joints to maintain a posture that provides the user with a feeling of weightlessness. The joints may also be driven to provide haptic feedback to the user. This haptic feedback may, for example, be force feedback via the hand controller pushing the user's hand. The haptic feedback may be a vibration, hum, or click transmitted to the user's hand via the hand controller. The joints are not otherwise driven.The first axis 404 is maintained in the same orientation with respect to the console's support structure 302 by mechanically constraining the linkage 304. In an alternative implementation, the joints of the linkage 304 could instead be driven in response to sensed forces applied to the hand controller 301. In this alternative implementation, the joints of the linkage 304 could be driven such that the first axis 404 is always maintained in the same orientation with respect to the support structure 302.

[0071] The robot described herein may be a surgical robot to which a surgical instrument with a surgical end effector is attached. Alternatively, the robot may be an industrial robot or a robot for another function. The instrument could be an industrial tool.

[0072] The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, insofar as such features or combinations can be carried out by those skilled in the art based on the present description as a whole in light of the common knowledge of those skilled in the art, regardless of whether such features or combinations of features solve the problems disclosed herein, and without limiting the scope of the claims. The applicant points out that aspects of the present invention may consist of any of these individual features or a combination of features. In view of the foregoing description, it will be obvious to one skilled in the art that various modifications can be made within the scope of the invention.

Claims

[1] Console (202) for controlling a robot manipulator with an end effector (207), the console (202) comprising: a hand control (301) connected to a gimbal assembly (303); and a linkage (304) which is connected at its proximal end to a rigid support structure (302) and at its distal end to the gimbal assembly (303); wherein the gimbal assembly (303) comprises only three degrees of freedom, provided by only three joints (401, 402, 403), wherein a first joint (401) of the three joints (401, 402, 403) of the gimbal assembly (303) allows it to rotate about a first axis (404) with respect to the distal end of the linkage (304); and characterized by, that the linkage (304) and the gimbal assembly (303) are arranged such that in each embodiment of the linkage (304) and the gimbal assembly (304) the first axis (404) has the same orientation with respect to the support structure (302), wherein the linkage (304) has a parallelogram profile, thereby mechanically constraining the first axis (404) to have the same orientation with respect to the support structure (302) in each embodiment of the linkage (304); and wherein the console (202) is designed such that, when the console (202) is arranged on a horizontal surface, the first axis (404) is vertical in every embodiment of the linkage (304) and the gimbal assembly (303). [2] Console (202) according to claim 1, which is configured to fully accommodate a rotation of the hand control (301) by articulating the three joints (401, 402, 403) of the gimbal assembly (303). [3] Console (202) according to claim 1 or 2, which is configured to accommodate a displacement of the hand control (301) by articulating the linkage (304). [4] Console (202) according to one of the preceding claims, wherein the gimbal assembly (303) comprises: a first connection (407) and a second connection (408); a second joint (402) which allows the first joint (407) to rotate about a second axis (405) with respect to the second joint (408), the second axis (405) being perpendicular to the first axis (404); and a third joint (403) which enables the hand control (301) to rotate about a third axis (406) with respect to the second link (408), the third axis (406) being perpendicular to the second axis (405). [5] Console (202) according to claim 4, wherein from a central position of the cardan ring assembly (303) in which the first axis (404), the second axis (405) and the third axis (406) are all perpendicular to each other, the range of motion of the first joint (401) is limited such that it is able to rotate by more than 90° in any direction of rotation about the first axis (404). [6] Console (202) according to claim 5, wherein the first joint (401) is limited from the central position of the gimbal assembly (303) to a maximum rotation angle between 90° and 115° in one direction of rotation, causing the first connection (407) to move towards the distal end of the joint linkage (304). [7] Console (202) according to claim 5 or 6, wherein the first joint (401) is limited from the central position of the gimbal assembly (303) to a maximum rotation angle between 90° and 100° in one direction of rotation, causing the first connection (407) to move away from the distal end of the joint linkage (304). [8] Console (202) according to one of claims 4 to 7, wherein from a central position of the cardan ring assembly (303) in which the first axis (404), the second axis (405) and the third axis (406) are all perpendicular to each other, the range of motion of the second joint (402) is limited such that it is able to rotate less than 90° in any direction about the second axis (405). [9] Console (202) according to claim 8, wherein the second joint (402) is limited from the central position of the cardan ring assembly (303) to a maximum rotation angle between 80° and 90° in one direction of rotation, causing the second connection (408) to move towards the first connection (407). [10] Console (202) according to claim 7 or 8, wherein the second joint (402) is limited from the central position of the cardan ring assembly (303) to a maximum rotation angle between 80° and 90° in one direction of rotation, causing the second connection (408) to move away from the first connection (407). [11] Console (202) according to one of claims 4 to 10, wherein from a central position of the cardan ring assembly (303) in which the first axis (404), the second axis (405) and the third axis (406) are all perpendicular to each other, the range of motion of the third joint (403) is limited such that it is able to rotate less than or equal to 90° in any direction of rotation about the third axis (406). [12] Console (202) according to any of the preceding claims, further comprising: a position sensor (416) arranged at the first joint (401) to measure a yaw movement of the hand control (301) solely by detecting a rotation of the first joint (401) about the first axis (404); a position sensor (417) arranged at the second joint (402) to measure a tilting movement of the hand control (301) solely by detecting a rotation of the second joint (402) about the second axis (405); and a position sensor (418) which is arranged at the third joint (403) to measure a rolling movement of the hand control (301) solely by detecting a rotation of the third joint (403) about the third axis (406). [13] Console (202) according to one of the preceding claims, wherein the console (202) is a surgeon's console for controlling a surgical robot carrying a surgical instrument. [14] Console (202) according to one of the preceding claims for controlling a further robot manipulator with a further end effector (207), the console (202) further comprising: a further hand control (301) which is connected to a further gimbal assembly (303); and a further linkage (304) which is connected at its proximal end to the rigid support structure (302) and at its distal end to the further gimbal assembly (303); wherein the further gimbal assembly (303) comprises only three degrees of freedom, provided by only three joints (401, 402, 403), wherein a first joint (401) of the three joints of the further gimbal assembly (303) allows it to rotate about a fourth axis with respect to the distal end of the further joint linkage (304); and wherein the further linkage (304) and the further cardan ring assembly (303) are arranged such that in each embodiment of the further linkage (304) and the further cardan ring assembly (303) the fourth axis has the same orientation with respect to the supporting structure (304). [15] Console (202) according to claim 14, wherein the hand control (301) is configured to be operated by one hand of a user and the further hand control (301) is configured to be operated by the other hand of the user.

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