Methods of controlling motion of under-actuated joints in a surgical set-up structure
Robotic and/or surgical devices, systems, and methods include kinematic linkage structures and associated control systems configured to control movement of passive or under-actuated joints by coordinated joint braking of the under-actuated joints concurrent with driving of one or more driven joints. In one aspect, the methods include driving a set-up structure by pivoting an orienting platform supporting multiple manipulators back-and-forth in opposite directions while selectively braking the under-actuated joints to inhibit passive joint movement away from a reference joint state and releasing braking to facilitate movement of the joints toward the reference until each of the under-actuated joints of the multiple manipulators are at the respective reference states. In another aspect, a joint brake controller is provided that receives a motor torque input and converts the input to a brake control input by determining an impulse applied variable braking to deplete the impulse over time.
1. A robotic system comprising:
a first robotic arm comprising a first joint;
a link supporting the first robotic arm;
one or more driven joints supporting the link; and
a processor operatively coupled to the one or more driven joints, wherein the processor is configured to:
accelerate the link by driving the one or more driven joints and imparting a force or moment to the first robotic arm,
inhibit a passive movement of the first joint when the passive movement of the first joint operates to cause the first joint to move away from a reference state of the first joint, wherein the passive movement of the first joint is responsive to the force or moment imparted to the first robotic arm, and
facilitate the passive movement of the first joint when the passive movement of the first joint operates to cause the first joint to move towards the reference state.
2. The robotic system of claim 1 , wherein the processor is further configured to:
halt the passive movement of the first joint when the first joint is at the reference state.
3. The robotic system of claim 1 , further comprising:
a second robotic arm, wherein the reference state corresponds to a deployed configuration of the first robotic arm, wherein in the deployed configuration the first robotic arm is extended and spaced apart from the second robotic arm.
4. The robotic system of claim 1 , further comprising:
a second robotic arm, wherein the reference state corresponds to a stowed configuration of the first robotic arm, wherein in the stowed configuration the first robotic arm is contracted and disposed against or adjacent to the second robotic arm.
5. The robotic system of claim 1 , wherein the processor is further configured to:
determine at least one of the following using a sensed torque of the first joint:
when the passive movement of the first joint operates to cause the first joint to move away from the reference state, and
when the passive movement of the first joint operates to cause the first joint to move towards the reference state.
6. The robotic system of claim 1 , wherein:
the first robotic arm further comprises a first joint brake operatively coupled to the processor;
the processor is configured to inhibit the passive movement of the first joint by at least partly braking the first joint using the first joint brake; and
the processor is configured to facilitate the passive movement of the first joint by at least partly releasing the first joint using the first joint brake.
7. The robotic system of claim 1 , wherein the processor is configured to facilitate the passive movement of the first joint by:
selectively releasing braking of the first joint to allow the first joint to accelerate to a velocity; and
selectively applying braking to the first joint to maintain the first joint at the velocity or to decelerate the first joint.
8. The robotic system of claim 1 , wherein the processor is configured to accelerate the link by:
driving the one or more driven joints to accelerate the link in opposite directions over time.
9. The robotic system of claim 8 , wherein accelerating the link in opposite directions over time imparts an inertial force or moment to the first robotic arm such that a reaction force or torque in the first joint alternates between opposing directions over time.
10. The robotic system of claim 8 , wherein the processor is further configured to:
alternate between inhibiting the passive movement of the first joint and facilitating the passive movement of the first joint until the first joint is at the reference state.
11. The robotic system of claim 8 , wherein the link comprises a platform supporting the first robotic arm, wherein the one or more driven joints comprises a driven revolute joint, and wherein the processor is configured to accelerate the link by driving the driven revolute joint to rotate the platform about a vertically extending axis.
12. The robotic system of claim 11 , wherein the first joint comprises a revolute joint that revolves around a first joint axis, wherein the first joint axis extends vertically.
13. The robotic system of claim 11 , further comprising a second robotic arm supported by the platform, the second robotic arm comprising a second joint, wherein:
the first robotic arm further comprises a first joint brake operatively coupled to the processor;
the processor is configured to inhibit and facilitate the passive movement of the first joint by selectively applying the first joint brake;
accelerating the link by driving the one or more driven joints imparts a second force or moment to the second robotic arm; and
the processor is further configured to:
inhibit a passive movement of the second joint when the passive movement of the second joint operates to cause the second joint to move away from a reference state of the second joint, wherein the passive movement of the second joint is in response to the second force or moment imparted to the second robotic arm, and
facilitate the passive movement of the second joint when the passive movement of the second joint operates to cause the second joint to move towards the reference state of the second joint.
14. The robotic system of claim 1 , wherein the reference state comprises a joint position or a joint orientation.
15. The robotic system of claim 1 , wherein the processor is configured to accelerate the link by:
driving the one or more driven joints to accelerate the link to a first speed when a displacement of the first joint from the reference state exceeds a pre-determined displacement; and
driving the one or more driven joints to accelerate the link to a second speed lower than the first speed when the displacement of the first joint from the reference state does not exceed the pre-determined displacement.
16. The robotic system of claim 1 , wherein the processor is configured to facilitate the passive movement of the first joint by:
determining that a combination of a sensed state of the first joint and a sensed state of the link corresponds to sufficient force, moment, or momentum for the passive movement of the first joint to move the first joint to the reference state; and
releasing braking of the first joint in response to the determination.
17. The robotic system of claim 1 , wherein the first joint is an under-actuated joint.
18. A robotic system comprising:
a first robotic arm comprising a plurality of joints and a plurality of joint brakes, each joint of the plurality of joints being configured to be braked by at least one corresponding joint brake of the plurality of joints brakes, and each joint of the plurality of joints having an associated reference state corresponding to a desired configuration of the first robotic arm;
a platform linkage supporting the first robotic arm;
one or more driven joints physically coupled to the platform linkage; and
a processor operatively coupled to the one or more driven joints, wherein the processor is configured to accelerate the platform linkage by driving the one or more driven joints and imparting a force or moment to the first robotic arm;
wherein the processor is configured to, for each joint of the plurality of joints:
inhibit a passive movement of the joint when the passive movement of the joint operates to cause the joint to move away from the associated reference state of the joint, wherein the passive movement of the joint is in response to the force or moment imparted to the first robotic arm; and
facilitate the passive movement of the joint when the passive movement of the joint operates to cause the joint to move towards the associated reference state of the joint.
19. The robotic system of claim 18 , wherein
the processor is configured to accelerate the platform linkage by: driving the one or more driven joints to accelerate the platform linkage in opposite directions over time; and
the processor is further configured to, for each joint of the plurality of joints, alternate between inhibiting and facilitating the passive movement of the joint when the joint is displaced from the associated reference state of the joint.
20. The robotic system of claim 18 , wherein processor is configured to accelerate the platform linkage by:
driving the one or more driven joints to accelerate the platform linkage to a first speed when a displacement exceeds a pre-determined displacement, the displacement being of a first joint of the plurality of joints from the associated reference state associated with the first joint; and
driving the one or more driven joints to accelerate the platform linkage to a second speed lower than the first speed when the displacement is within the pre-determined displacement.
21. The robotic system of claim 18 , wherein at least one joint of the plurality of joints is an under-actuated joint.
22. The robotic system of claim 18 , wherein the processor is configured to:
facilitate the passive movement of a first joint of the plurality of joints while inhibiting the passive movement of a second joint of the plurality of joints by partially applying the corresponding joint brake of the second joint.
23. A tele-operational system comprising:
a first robotic arm comprising a first joint and a first joint brake;
a platform linkage supporting the first robotic arm;
one or more driven joints supporting the platform linkage; and
a processor operatively coupled to the one or more driven joints, wherein the processor is configured to:
accelerate the platform linkage by driving the one or more driven joints, thereby imparting a force or moment to the first robotic arm,
sense a joint torque of the first joint,
determine, using the joint torque, if a passive movement of the first joint in response to the force or moment operates to cause the first joint to move towards or away from a reference state of the first joint,
inhibit the passive movement of the first joint in response to determining that the passive movement of the first joint operates to cause the first joint to move away from the reference state of the first joint by at least partly applying braking to the first joint,
facilitate the passive movement of the first joint in response to determining that the passive movement of the first joint operates to cause the first joint to move the first joint towards the reference state of the first joint by at least partly releasing braking applied to the first joint, and
halt the passive movement of the first joint in response to the first joint being at the reference state of the first joint.
24. The tele-operational system of claim 23 , further comprising a second robotic arm, the second robotic arm comprising a second joint and a second joint brake, wherein:
accelerating the platform linkage by driving the one or more driven joints imparts a second force or moment to the second robotic arm; and
the processor is further configured to, while facilitating the passive movement of the first joint, inhibit a passive movement of the second joint by at least partially applying the second joint brake when the passive movement of the second joint operates to cause the second joint to move away from a reference state of the second joint, wherein the passive movement of the second joint is in response to the second force or moment to the second robotic arm.
25. The tele-operational system of claim 23 , wherein
the processor is configured to accelerate the platform linkage by: driving the one or more driven joints to accelerate the platform linkage in opposite directions over time, wherein accelerating the platform linkage between opposite directions imparts an inertial force or moment to the first robotic arm such that a reaction force or torque in the first joint alternates between opposing directions; and
the processor is further configured to: alternate between inhibiting the passive movement of the first joint and facilitating the passive movement of the first joint until the first joint is at the reference state of the first joint.