Systems and methods for cancellation of joint motion using the null-space

Patent metadata

Field	Value
Publication number	US-9675421-B2
Application number	US-201514802866-A
Country	US
Kind code	B2
Filing date	Jul 17, 2015
Priority date	Sep 17, 1999
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

Devices, systems, and methods are disclosed for cancelling movement of one or more joints of a telesurgical manipulator to effect manipulation movement of an end effector. Methods include calculating movement of joints within a null-perpendicular space to effect desired end effector movement while calculating movement of one or more locked joints within a null-space to cancel the movement of the locked joints within the null-perpendicular-space. Methods may further include calculating movement of one or more joints to effect an auxiliary movement or a reconfiguration movement that may include movement of one or more locked joints. The auxiliary and reconfiguration movements may overlay the manipulation movement of the joints to allow movement of the locked joints to effect the auxiliary movement or reconfiguration movement, while the movement of the locked joints to effect manipulation is canceled. Various configurations for devices and systems utilizing such methods are provided herein.

First claim

What is claimed is:

1. A method comprising:
receiving a command to move an end effector of a manipulator arm in an end-effector displacement, the manipulator arm including a proximal portion coupled to a base, a distal portion including the end effector, and a plurality of joints between the distal portion and the base, the plurality of joints being operable to allow a range of differing states of the plurality of joints for a given state of the distal portion;
designating one or more non-moving joints of the plurality of joints;
determining an end-effector-displacing movement of the plurality of joints to effect the end-effector displacement;
determining a cancellation movement of the plurality of joints, the cancellation movement corresponding to a non-moving end effector, and the cancellation movement providing a cancellation of joint movement for each of the one or more non-moving joints when the cancellation movement is combined with the end-effector displacing movement; and
driving the plurality of joints by combining the end-effector-displacing movement and the cancellation movement to effect the end-effector displacement.

2. The method of claim 1 , wherein for each joint of the one or more non-moving joints, the corresponding joint velocities for the end-effector-displacing movement and the cancellation movement combine to effect the cancellation of joint movement for that joint.

3. The method of claim 1 , further comprising:
calculating values for the cancellation movement so that, for each of the one or more non-moving joints, a corresponding joint velocity for the cancellation movement cancels a corresponding joint velocity for the end-effector-displacing movement.

4. The method of claim 1 , wherein determining the end-effector-displacing movement of the plurality of joints includes calculating joint velocities of the plurality of joints from directions that correspond to a moving end effector; and
determining the cancellation movement of the plurality of joints includes calculating joint velocities of the plurality of joints from directions that correspond to a non-moving end effector.

5. The method of claim 1 , further comprising:
calculating a matrix that relates joint velocities of the plurality of joints to motions of the end effector, the matrix including a plurality of joint-velocity directions corresponding to a moving end-effector and one or more joint-velocity directions corresponding to a non-moving end effector;
determining the end-effector-displacing movement of the plurality of joints from a calculation based on the plurality of joint-velocity directions corresponding to a moving end-effector; and
determining the cancellation movement of the plurality of joints from a calculation based on the one or more joint-velocity directions corresponding to a non-moving end-effector.

6. The method of claim 1 , wherein determining the end-effector-displacing movement of the plurality of joints includes calculating joint velocities of the plurality of joints within a null-perpendicular space of a Jacobian matrix for the plurality of joints; and
determining the cancellation movement of the plurality of joints includes calculating joint velocities of the plurality of joints within a null space of the Jacobian, the null space being orthogonal to the null-perpendicular space.

7. The method of claim 1 , further comprising:
determining an auxiliary movement of a first joint set of the plurality of joints, the first joint set being selected from the one or more non-moving joints of the plurality of joints, and the auxiliary movement being determined from directions that correspond to a non-moving end effector; and
driving the plurality of joints by combining the auxiliary movement with the end-effector-displacing movement and the cancellation movement to effect a goal of the auxiliary movement, the goal of the auxiliary movement including a desired pose, a desired configuration, or a collision avoidance for the manipulator arm.

8. A system comprising:
a manipulator arm including a proximal portion coupled to a base, a distal portion including an end effector, and a plurality of joints between the distal portion and the base, the plurality of joints being operable to allow a range of differing states of the plurality of joints for a given state of the distal portion; and
a motion unit including one or more processors configured to perform operations including:
receiving a command to move the end effector of the manipulator arm in an end-effector displacement;
designating one or more non-moving joints of the plurality of joints;
determining an end-effector-displacing movement of the plurality of joints to effect the end-effector displacement;
determining a cancellation movement of the plurality of joints, the cancellation movement corresponding to a non-moving end effector, and the cancellation movement providing a cancellation of joint movement for each of the one or more non-moving joints when the cancellation movement is combined with the end-effector displacing movement; and
driving the plurality of joints by combining the end-effector-displacing movement and the cancellation movement to effect the end-effector displacement.

9. The system of claim 8 , wherein for each joint of the one or more non-moving joints, the corresponding joint velocities for the end-effector-displacing movement and the cancellation movement combine to effect the cancellation of joint movement for that joint.

10. The system of claim 8 , wherein the one or more processors are further configured to perform operations including:
calculating values for the cancellation movement so that, for each of the one or more non-moving joints, a corresponding joint velocity for the cancellation movement cancels a corresponding joint velocity for the end-effector-displacing movement.

11. The system of claim 8 , wherein determining the end-effector-displacing movement of the plurality of joints includes calculating joint velocities of the plurality of joints from directions that correspond to a moving end effector; and
determining the cancellation movement of the plurality of joints includes calculating joint velocities of the plurality of joints from directions that correspond to a non-moving end effector.

12. The system of claim 8 , wherein the one or more processors are further configured to perform operations including:
calculating a matrix that relates joint velocities of the plurality of joints to motions of the end effector, the matrix including a plurality of joint-velocity directions corresponding to a moving end-effector and one or more joint-velocity directions corresponding to a non-moving end effector;
determining the end-effector-displacing movement of the plurality of joints from a calculation based on the plurality of joint-velocity directions corresponding to a moving end-effector; and
determining the cancellation movement of the plurality of joints from a calculation based on the one or more joint-velocity directions corresponding to a non-moving end-effector.

13. The system of claim 8 , wherein determining the end-effector-displacing movement of the plurality of joints includes calculating joint velocities of the plurality of joints within a null-perpendicular space of a Jacobian matrix for the plurality of joints; and
determining the cancellation movement of the plurality of joints includes calculating joint velocities of the plurality of joints within a null space of the Jacobian, the null space being orthogonal to the null-perpendicular space.

14. The system of claim 8 , wherein the one or more processors are further con

Assignees

• Intuitive Surgical Operations

Inventors

• Hourtash Arjang M
• Hingwe Pushkar

Classifications

• G05B2219/40367

  Redundant manipulator · CPC title

• G05B2219/40365

  Configuration control, select other tasks by configuration of link positions · CPC title

• G05B2219/40362

  Elbow high or low, avoid obstacle collision with redundancy control · CPC title

• B25J9/1643

  redundant control · CPC title

• B25J9/1607

  Calculation of inertia, jacobian matrixes and inverses · CPC title