Systems and methods for tracking a path using the null-space

Patent metadata

Field	Value
Publication number	US-9296104-B2
Application number	US-201414218862-A
Country	US
Kind code	B2
Filing date	Mar 18, 2014
Priority date	Sep 17, 1999
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

Devices, systems, and methods for providing a desired movement of one or more joints of a manipulator arm having a plurality of joints with redundant degrees of freedom while effecting commanded movement of a distal end effector of the manipulator. Methods include defining a constraint, such as a network of paths, within a joint space defined by the one or more joints and determining a movement of the plurality of joints within a null-space to track the constraints with the one or more joints. Methods may further include calculating a reconfiguration movement of the joints and modifying the constraints to coincide with a reconfigured position of the one or more joints. Various configurations for devices and systems utilizing such methods are provided herein.

First claim

What is claimed is:

1. A robotic method for a manipulator arm that includes a movable distal end effector, a proximal portion coupled to a base, and a plurality of joints between a distal portion and the base, the plurality of joints together having sufficient degrees of freedom to allow a range of differing joint states for an individual state of the distal end effector, and the method comprising:
defining a position-based constraint of one or more joints of the plurality of joints within a joint space of the plurality of joints, the position-based constraint including one or more paths corresponding to a desired movement of the one or more joints within the joint space of the plurality of joints;
receiving a manipulation command to move the end effector with a desired end effector movement;
calculating an end effector displacing movement of the plurality of joints to effect the desired end effector movement, wherein calculating the end effector displacing movement of the plurality of joints comprises calculating joint velocities within a null-perpendicular-space of a Jacobian;
calculating a tracking movement of the plurality of joints so as to move a position of the one or more joints towards at least one of the one or more paths, wherein calculating the tracking movement comprises calculating joint velocities of the one or more joints within a null-space of the Jacobian in a direction towards the at least one of the one or more paths, the null-perpendicular space being orthogonal to the null-space; and
driving the plurality of joints according to the calculated movements so as to effect the desired end effector movement concurrently with the desired movement of the one or more joints.

2. The method of claim 1 , wherein the one or more paths each have at least one dimension, and the one or more paths are each 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 tracking movement comprises:
defining an attractive potential field between a calculated position of the one or more joints and the one or more paths, wherein an increase in potential of the potential field corresponds to an increase in distance between the calculated position and the one or more paths;
determining a potential between the calculated position and the one or more paths; and
calculating the tracking movement by using the potential to determine the direction towards the at least one of the one or more paths.

5. The method of claim 2 , wherein the one or more paths comprise a network of paths that are piecewise continuous so as to provide consistent and predictable movement along the one or more paths when the one or more joints are driven along the one or more paths.

6. The method of claim 5 , wherein calculating the tracking movement comprises:
determining a movement of the plurality of joints within the joint space based on a potential determined by the one or more joints; and
determining joint velocities of the plurality of joints that track the position-based constraint of the one or more joints by projecting the movement of the plurality of joints on a null space of the Jacobian.

7. The method of claim 2 , wherein the at least two joints comprise a first and a second joint, and wherein movement of the first joint controls a pitch of a distal instrument shaft of the manipulator arm 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.

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

9. The method of claim 1 , further comprising:
driving at least one joint of the plurality of joints to effect a desired reconfiguration of the manipulator arm;
calculating a reconfiguration movement of the one or more joints 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 is 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; and
driving the plurality of joints according to the calculated movements while driving the at least one joint to effect the desired reconfiguration of the manipulator arm and the desired movement of the one or more joints while maintaining a desired state of the end effector.

10. The method of claim 9 , wherein modifying the position-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 at least one joint, wherein the calculated movements of the manipulator arm are determined by a processor having a tissue manipulation mode and a clutch mode, the processor in the tissue manipulation mode calculating 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. 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 plurality of joints together providing sufficient degrees of freedom to allow a range of joint states for an individual 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 perform operations including:
calculating an end effector displacing movement of the plurality of joints in response to the manipulation command by calculating joint velocities within a null-perpendicular-space of a Jacobian;
defining a position-based constraint of one or more joints of the plurality of joints within a joint space of the plurality of joints, the position-based constraint including one or more paths corresponding to a desired movement of the one or more joints within the joint space of the plurality of joints;
calculating a tracking movement of the plurality of joints so that a position of the one or more joints tracks at least one of the one or more paths, wherein calculating the tracking movement comprises calculating joint velocities of the one or more joints within a null-space of the Jacobian in a direction towards the at least one of the one or more paths, the null-space being orthogonal to the null-perpendicular space; and
transmitting a command to the manipulator arm

Assignees

• Intuitive Surgical Operations

Inventors

• Swarup Nitish
• Hourtash Arjang
• Mohr Paul

Classifications

• G05B2219/40359

  Constraint, physical limitations · CPC title

• A61B34/76

  Manipulators having means for providing feel, e.g. force or tactile feedback · CPC title

• G05B2219/40339

  Avoid collision · CPC title

• A61B2090/065

  for measuring contact or contact pressure · CPC title

• A61B34/37

  Leader-follower robots (A61B34/35 takes precedence) · CPC title