Whole body manipulation on a legged robot using dynamic balance

Patent metadata

Field	Value
Publication number	US-10351189-B2
Application number	US-201615377559-A
Country	US
Kind code	B2
Filing date	Dec 13, 2016
Priority date	Dec 13, 2016
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A robot system includes: an upper body section including one or more end-effectors; a lower body section including one or more legs; and an intermediate body section coupling the upper and lower body sections. An upper body control system operates at least one of the end-effectors. The intermediate body section experiences a first intermediate body linear force and/or moment based on an end-effector force acting on the at least one end-effector. A lower body control system operates the one or more legs. The one or more legs experience respective surface reaction forces. The intermediate body section experiences a second intermediate body linear force and/or moment based on the surface reaction forces. The lower body control system operates the one or more legs so that the second intermediate body linear force balances the first intermediate linear force and the second intermediate body moment balances the first intermediate body moment.

First claim

What is claimed is:

1. A robot system comprising:
a body including:
an upper body section including one or more movable end-effectors;
a lower body section including one or more legs configured to contact a surface; and
an intermediate body section coupling the upper body section and the lower body section; and

a control system implemented with one or more processors, the control system including:
an upper body control system configured to operate at least one of the end-effectors, the at least one end-effector experiencing an end-effector force based on the operation by the upper body control system, and the intermediate body section experiencing at least one of a first intermediate body linear force or a first intermediate body moment based on the end-effector force; and
a lower body control system configured to operate the one or more legs in response to the operation of the at least one end-effector, the one or more legs experiencing respective reaction forces from the surface based on the operation by the lower body control system, the intermediate body section experiencing at least one of a second intermediate body linear force or a second intermediate body moment based on the reaction forces,

wherein the lower body control system is configured to operate the one or more legs so that the second intermediate body linear force balances the first intermediate linear force and the second intermediate body moment balances the first intermediate body moment,
wherein the lower body control system is further configured to position the intermediate body section according to a first set of degrees of freedom based on the operation of the one or more legs, and
wherein the upper body control system is further configured to position the intermediate body section according to a second set of degrees of freedom based on the operation of the at least one end-effector, and the upper body control system is constrained from positioning the intermediate body section according to the first set of degrees of freedom.

2. The robot system of claim 1 , wherein the upper body control system is configured to communicate, to the lower body control system, information relating to the first intermediate body linear force and the first intermediate body moment.

3. The robot system of claim 1 , wherein the upper body control system is configured to process the lower body section as a virtual link coupled to the intermediate body section.

4. The robot system according to claim 1 , wherein the first set of degrees of freedom for positioning the intermediate body section includes translation along a first axis and a second axis, and the second set of degrees of freedom for positioning the intermediate body section includes rotation about three axes and translation along a third axis.

5. The robot system according to claim 1 , wherein the lower body section consists of two legs, and each leg includes a foot configured to contact the surface directly,
for a given position of the feet, the control system is configured to determine whether the second intermediate body linear force can balance the first intermediate linear force and the second intermediate body moment can balance the first intermediate body moment, and
in response to determining that the second intermediate body linear force cannot balance the first intermediate linear force or the second intermediate body moment cannot balance the first intermediate body moment, the lower body control system is configured to reposition at least one of the feet on the surface.

6. The robot system according to claim 5 , wherein the lower body control system is configured to adjust the repositioning of the at least one of the feet according to a gait.

7. The robot system of claim 1 , wherein the lower body control system is configured to operate the one or more legs in response to the operation of the at least one end-effector while the one or more legs are moving according to a gait.

8. A method for controlling a robot system, the robot system including a body, the body including:
an upper body section including one or more movable end-effectors;
a lower body section including one or more legs configured to contact a surface; and
an intermediate body section coupling the upper body section and the lower body section,
a control system implemented with one or more processors, the control system including a lower body control system and an upper control system,
the method comprising:
operating, with the upper body control system, at least one of the end-effectors, the at least one end-effector experiencing an end-effector force based on the operation by the upper body control system, and the intermediate body section experiencing at least one of a first intermediate body linear force or a first intermediate body moment based on the end-effector force;
operating, with the lower body control system, the one or more legs in response to the operation of the at least one end-effector, the one or more legs experiencing respective reaction forces from the surface based on the operation by the lower body control system, the intermediate body section experiencing at least one of a second intermediate body linear force or a second intermediate body moment based on the reaction forces;
positioning, with the lower body control system, the intermediate body section according to a first set of degrees of freedom based on the operation of the one or more legs; and
positioning, with the upper body control system, the intermediate body section according to a second set of degrees of freedom based on the operation of the at least one end-effector,

wherein the lower body control system is configured to operate the one or more legs so that the second intermediate body linear force balances the first intermediate linear force and the second intermediate body moment balances the first intermediate body moment, and
wherein the upper body control system is constrained from positioning the intermediate body section according to the first set of degrees of freedom.

9. The method of claim 8 , further comprising communicating, from the upper body control system to the lower body control system, information relating to the first intermediate body linear force and the first intermediate body moment.

10. The method system of claim 8 , further comprising abstracting, with the upper body control system, the lower body section as a virtual link coupled to the intermediate body section.

11. The method according to claim 8 , wherein the first set of degrees of freedom for positioning the intermediate body section includes translation along a first axis and a second axis, and the second set of degrees of freedom for positioning the intermediate body section includes rotation about three axes and translation along a third axis.

12. The method according to claim 8 , wherein the lower body section consists of two legs and each leg includes a foot configured to contact the surface directly, and the method further comprises:
for a given position of the feet, determining, with the control system, whether the second intermediate body linear force can balance the first intermediate linear force and the second intermediate body moment can balance the first intermediate body moment; and
in response to determining that the second intermediate body linear force cannot balance the first intermediate linear force or the second intermediate body moment cannot balance the first intermediate body moment, repositioning, with the lower body control system, at least one of the feet on the surface.

13. The method according to claim 12 , further comprising adjusting, with the l

Assignees

• Boston Dynamics Inc

Inventors

• Blankespoor Kevin
• Stephens Benjamin
• Hudson Nicolas
• Abe Yeuhi
• Barry Jennifer

Classifications

• Y10S901/01

  Mobile robot · CPC title

• B62D57/02

  with ground-engaging propulsion means, e.g. walking members · CPC title

• B62D57/024

  specially adapted for moving on inclined or vertical surfaces (endless-track vehicles for ascending or descending stairs B62D55/075; hand-carts with provision for travelling up or down stairs B62B5/02) · CPC title

• B25J9/1633

  compliant, force, torque control, e.g. combined with position control · CPC title

• B25J9/162 Primary

  Mobile manipulator, movable base with manipulator arm mounted on it · CPC title