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

Patent metadata

Field	Value
Publication number	US-2017246743-A1
Application number	US-201715456394-A
Country	US
Kind code	A1
Filing date	Mar 10, 2017
Priority date	Mar 15, 2013
Publication date	Aug 31, 2017
Grant date	—

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

1 . (canceled)

2 . A method for moving a manipulator assembly that is adapted to support a tool that includes a tool tip, the manipulator assembly comprising a proximal portion coupled to a base, and a plurality of joints between the tool tip and the base, the plurality of joints having sufficient degrees of freedom to allow a range of differing joint states for a given state of the tool tip, 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; calculating a tracking movement of the plurality of joints so as to move one or more positions of the one or more joints of the plurality of joints towards the position-based constraint, wherein calculating the tracking movement of the plurality of joints comprises calculating joint velocities of the plurality of joints from joint-velocity directions that correspond to the tool tip not moving; and driving the plurality of joints according to the calculated tracking movement.

3 . The method of claim 2 , wherein the joint-velocity directions that correspond to the tool tip not moving are within a null space of a Jacobian of the manipulator assembly.

4 . The method of claim 2 , further comprising:
receiving a manipulation command to move the tool tip with a desired tool-tip movement; calculating a tool-tip displacing movement of the plurality of joints to effect the desired tool-tip movement, wherein calculating the tool-tip displacing movement of the plurality of joints comprises calculating joint velocities of the plurality of joints from joint-velocity directions that correspond to the tool tip moving; and driving the plurality of joints according to the calculated tool-tip displacing movement so as to effect the tool-tip displacing movement concurrently with the tracking movement.

5 . The method of claim 4 , wherein the joint-velocity directions that correspond to the tool tip not moving are within with a null space of a Jacobian of the manipulator assembly, and the joint-velocity directions that correspond to the tool tip moving are within a null-perpendicular space of the Jacobian.

6 . The method of claim 2 , wherein a first path of the one or more paths of the position-based constraint has at least one dimension and is defined within a subspace of the joint space of the plurality of joints by at least two joints of the plurality of joints.

7 . The method of claim 2 , wherein the one or more paths of the position-based constraint include a network of piecewise continuous paths within the joint space of the plurality of joints.

8 . The method of claim 2 , wherein calculating the tracking movement comprises:
defining a potential field between one or more calculated positions of the one or more joints of the plurality of joints and the one or more paths of the position-based constraint, wherein an increasing potential of the potential field corresponds to an increasing distance between the one or more calculated positions and the one or more paths; determining from the potential field a potential between the one or more calculated positions and the one or more paths; and calculating the tracking movement by using the potential to determine a direction from the one or more calculated positions towards the one or more paths.

9 . The method of claim 2 , wherein calculating the tracking movement comprises:
determining a first movement of the plurality of joints within the joint space of the plurality of joints by evaluating a potential function of the one or more joints of the position-based constraint; and determining the joint velocities of the plurality of joints for the tracking movement by projecting the first movement of the plurality of joints onto a null space of a Jacobian of the manipulator assembly.

10 . A system comprising:
a manipulator assembly that is adapted to support a tool that includes a tool tip, the manipulator assembly comprising a proximal portion coupled to a base, and a plurality of joints between the tool tip and the base, the plurality of joints having sufficient degrees of freedom to allow a range of differing joint states for a given state of the tool tip; one or more processors operably connected to the manipulator assembly, the one or more processors being configured to perform operations including:
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 as to move one or more positions of the one or more joints of the plurality of joints towards the position-based constraint, wherein calculating the tracking movement of the plurality of joints comprises calculating joint velocities of the plurality of joints from joint-velocity directions that correspond to the tool tip not moving; and
causing the manipulator assembly to drive the plurality of joints according to the calculated tracking movement.

11 . The system of claim 10 , wherein the joint-velocity directions that correspond to the tool tip not moving are within a null space of a Jacobian of the manipulator assembly.

12 . The system of claim 10 , further comprising:
an input device for receiving a manipulation command to move the tool tip with a desired tool-tip movement, the input device being operably connected to the one or more processors, wherein the operations of the one or more processors further comprise:
calculating a tool-tip displacing movement of the plurality of joints to effect the desired tool-tip movement, wherein calculating the tool-tip displacing movement of the plurality of joints comprises calculating joint velocities of the plurality of joints from directions that correspond to the tool tip moving; and
causing the manipulator assembly to drive the plurality of joints according to the calculated tool-tip displacing movement so as to effect the tool-tip displacing movement concurrently with the tracking movement.

13 . The system of claim 12 , wherein the joint-velocity directions that correspond to the tool tip not moving are within with a null space of a Jacobian of the manipulator assembly, and the joint-velocity directions that correspond to the tool tip moving are within a null-perpendicular space of the Jacobian.

14 . The system of claim 10 , wherein a first path of the one or more paths of the position-based constraint has at least one dimension and is defined within a subspace of the joint space of the plurality of joints by at least two joints of the plurality of joints.

15 . The system of claim 10 , wherein the one or more paths of the position-based constraint include a network of piecewise continuous paths within the joint space of the plurality of joints.

16 . The system of claim 10 , wherein calculating the tracking movement comprises:
defining a potential field between one or more calculated positions of the one or more joints of the plurality of joints and the one or more paths of the position-based constraint, wherein an increasing potential of the potential field corresponds to an increasing distance between the one or more calculated positions and the one or more paths; determining from the potential field a potential betwe

Assignees

• Intuitive Surgical Operations

Inventors

• Swarup Nitish
• Hourtash Arjang M
• Mohr Paul W

Classifications

• A61B34/30

  Surgical robots · CPC title

• B25J9/1643 Primary

  redundant control · CPC title

• A61B34/37

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

• B25J18/007

  the end effector rotating around a fixed point · CPC title

• G05B2219/40339

  Avoid collision · CPC title