Systems and methods for facilitating access to edges of cartesian-coordinate space using the null space

Patent metadata

Field	Value
Publication number	US-9375284-B2
Application number	US-201414218871-A
Country	US
Kind code	B2
Filing date	Mar 18, 2014
Priority date	Sep 17, 1999
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

Devices, systems, and methods for providing increased range of movement of the end effector of a manipulator arm having a plurality of joints with redundant degrees of freedom. Methods include defining a position-based constraint within a joint space defined by the at least one joint, determining a movement of the joints along the constraint within a null-space and driving the joints according to a calculated movement to effect the commanded movement while providing an increased end effector range of movement, particularly as one or more joints approach a respective joint limit within the joint space.

First claim

What is claimed is:

1. A robotic method comprising:
providing a manipulator arm including a movable distal surgical end effector, a proximal portion coupled to a base, and a plurality of joints between the end effector and the base, the plurality of joints having sufficient degrees of freedom to allow a range of differing joint states for a given end effector state;
defining a position-based constraint of one or more joints within a joint space of the plurality of joints for which increased range of movement is desired;
receiving a manipulation command to move the end effector with a desired end effector movement;
calculating an end effector displacing movement of the one or more joints to effect the desired end effector movement, wherein calculating the end effector displacing movement of the joints comprises calculating joint velocities within a null-perpendicular-space of a Jacobian; and
calculating a facilitating movement of a set of joint(s) of the plurality along the position-based constraint, the facilitating movement increasing the available range of movement of the end effector, wherein calculating the facilitating movement comprises calculating joint velocities of the one or more joints within a null-space of the Jacobian, the null-space being orthogonal to the null-perpendicular space; and
driving the joints according to the calculated movements so as to effect the desired end effector movement while providing the increased range of movement of the end effector.

2. The method of claim 1 , wherein the positional constraint comprises one or more surfaces having at least one dimension, wherein the one or more surfaces are defined within a subspace of the joint space defined by at least two joints of the plurality of joints.

3. The method of claim 2 , wherein the at least two joints have independent joint states such that the subspace comprises at least two dimensions.

4. The method of claim 2 , wherein calculating the facilitating movement comprises:
defining an attractive potential field based on a calculated position of the at least one joint within the joint space such that an decrease in potential drives the joints;
determining a potential between the calculated position and the one or more surfaces associated with the one or more joints; and
calculating the facilitating movement using the potential.

5. The method of claim 4 , wherein the potential field is associated with movement along the surface that corresponds to increased range of movement of one or both of the at least two joints.

6. The method of claim 4 , wherein calculating the facilitating movement comprises:
determining a movement of the plurality of joints within the joint space based on the potential of the at least joint; and
projecting the movement of the plurality of joints on a null-space of the Jacobian to determine joint velocities of the plurality of joints that extend the at least two joints toward the constraint.

7. The method of claim 6 , wherein a distal portion of the manipulator arm is coupled with an instrument holder to releasably support a surgical instrument having an elongate shaft extending distally to the end effector, wherein the instrument shaft pivots about a remote center during surgery.

8. The method of claim 2 , wherein the at least two joints comprise a first and a second joint, wherein movement of the first joint controls a pitch of a distal instrument shaft of the manipulator and movement of the second joint pivots the instrument shaft laterally relative to a plane along which a portion of the manipulator arm proximal of the second joint extends.

9. The method of claim 1 , further comprising:
driving at least one joint of the plurality to effect a desired reconfiguration of the manipulator arm in response to a user input reconfiguration command;
calculating a reconfiguration movement of one or more joints of the plurality in response to the driving of the at least one joint so that the calculated movement in combination with driving of the at least one joint extends within the null-space;
modifying the position-based constraint in response to a determined position of the one or more joints within the calculated reconfiguration movement;
driving the joints according to the calculated movements while driving the at least one joint according to the user input reconfiguration command so as to maintain a desired state of the end effector while providing the increased range of movement of the one or more joints.

10. The method of claim 9 , wherein modifying the positioned-based constraint comprises translating a position or orientation of the constraint within the joint space based on the calculated reconfiguration movement.

11. The method of claim 9 , wherein modifying the position-based constraint comprises selecting one of a set of position-based constraints in response to the determined position of the one or more joints.

12. The method of claim 9 , wherein driving the at least one joint comprises manual articulation of the joint, wherein movement of the manipulator arm is determined by a processor having a tissue manipulation mode and a clutch mode, the processor in the tissue manipulation mode calculating the joint movements to provide the desired end effector movement in response to the end effector manipulation command, the processor in the clutch mode driving at least one other joint in response to the manual articulation of the at least one joint so as to maintain the desired state of the end effector, and
wherein modifying the position-based constraint occurs in response to the determined position of the one or more joints reconfigured within the clutch mode.

13. The method of claim 1 , wherein the positional constraint comprises one or more paths having at least one dimension, wherein the one or more paths are defined within a subspace of the joint space defined by at least two joints of the plurality of joints.

14. A system comprising:
a manipulator arm configured for robotically moving a distal end effector relative to a proximal base, the manipulator arm having a plurality of joints between the distal end effector and the proximal portion coupled to the base, the joints providing sufficient degrees of freedom to allow a range of joint states for a given state of the distal end effector;
an input for receiving a manipulation command to move the end effector with a desired end effector movement; and
a processor coupling the input device to the manipulator arm, the processor configured to:
calculate an end effector displacing movement of the joints in response to the manipulation command by calculating joint velocities within a null-perpendicular-space of a Jacobian;
define a position-based constraint of one or more joints of the plurality within an associated joint space, the constraint corresponding to an increased range of movement of the one or more joints;
calculate a facilitating movement of the one or more joints within a null-space of the Jacobian that moves the one or more joints toward the constraint, the null-space being orthogonal to the null-perpendicular space; and
transmit a command to the manipulator arm to drive the plurality of joints according to the calculated movements so as to effect the desired end effector movement concurrent with the desired movement of the one or more joints.

15. The system of claim 14 wherein the one or more joints defining a subspace of the joint space and the constraint is defined as one or more surfaces within the subspace.

16. The system of claim 15 , wherein the at least two joints have independent joints states su

Assignees

• Intuitive Surgical Operations

Inventors

• Hourtash Arjang

Classifications

• G05B2219/40371

  Control trajectory to avoid joint limit as well as obstacle collision · CPC title

• B25J9/1666

  Avoiding collision or forbidden zones · CPC title

• B25J9/1643

  redundant control · CPC title

• A61B19/2203 Primary

  Human Necessities · mapped topic

• B25J18/007

  the end effector rotating around a fixed point · CPC title