Monitoring a kinematically redundant robot

Patent metadata

Field	Value
Publication number	US-9724827-B2
Application number	US-201414309241-A
Country	US
Kind code	B2
Filing date	Jun 19, 2014
Priority date	Jun 19, 2013
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A method for monitoring a kinematically redundant robot includes detecting joint forces acting in the joints of the robot, determining an external work force between a robot-permanent reference point and an environment based on the detected joint forces, determining a further monitoring variable that is at least substantially independent of an external force acting on the robot-permanent reference point based on the detected joint forces, and monitoring the determined external work force and the determined further monitoring variable.

First claim

What is claimed is:

1. A method for monitoring a kinematically redundant robot, the method comprising:
detecting joint forces acting in joints of the robot;
determining an external work force between a robot-permanent reference point and an environment based on the detected joint forces;
determining, based on the detected joint forces, a further monitoring variable which is at least substantially independent of an external force acting on the robot-permanent reference point;
monitoring the determined external work force and the determined further monitoring variable; and
controlling the robot with a controller based on at least one of the determined external work force or the determined further monitoring variable.

2. The method of claim 1 , further comprising:
triggering a first safety reaction when the determined external work force fulfills a first variably definable monitoring condition; and
triggering the first safety reaction or a second safety reaction when the determined further monitoring variable fulfills the first monitoring condition or a second monitoring condition.

3. The method of claim 2 , wherein the second monitoring condition is a variably pre-definable monitoring condition.

4. The method of claim 1 , wherein the further monitoring variable comprises an external force spaced apart from the robot-permanent reference point.

5. The method of claim 2 , wherein the further monitoring variable comprises an external force spaced apart from the robot-permanent reference point.

6. The method of claim 1 , wherein the joint forces are mapped onto the external work force by a first linear mapping.

7. The method of claim 2 , wherein the joint forces are mapped onto the external work force by a first linear mapping.

8. The method of claim 4 , wherein the joint forces are mapped onto the external work force by a first linear mapping.

9. The method of claim 5 , wherein the joint forces are mapped onto the external work force by a first linear mapping.

10. The method of claim 6 , wherein the first linear mapping is a pseudoinverse of a transposed Jacobian matrix for the robot-permanent reference point.

11. The method of claim 7 , wherein the first linear mapping is a pseudoinverse of a transposed Jacobian matrix for the robot-permanent reference point.

12. The method of claim 8 , wherein the first linear mapping is a pseudoinverse of a transposed Jacobian matrix for the robot-permanent reference point.

13. The method of claim 9 , wherein the first linear mapping is a pseudoinverse of a transposed Jacobian matrix for the robot-permanent reference point.

14. The method of claim 10 , wherein the same joint forces are mapped onto the further monitoring variable by a second linear mapping.

15. The method of claim 11 , wherein the same joint forces are mapped onto the further monitoring variable by a second linear mapping.

16. The method of claim 12 , wherein the same joint forces are mapped onto the further monitoring variable by a second linear mapping.

17. The method of claim 13 , wherein the same joint forces are mapped onto the further monitoring variable by a second linear mapping.

18. A method for monitoring a kinematically redundant robot, the method comprising:
detecting joint forces acting in joints of the robot;
determining an external work force between a robot-permanent reference point and an environment based on the detected joint forces;
determining, based on the detected joint forces, a further monitoring variable which is at least substantially independent of an external force acting on the robot-permanent reference point; and
monitoring the determined external work force and the determined further monitoring variable;
wherein the joint forces are mapped onto the external work force by a first linear mapping;
wherein the first linear mapping is a pseudoinverse of a transposed Jacobian matrix for the robot-permanent reference point;
wherein the same joint forces are mapped onto the further monitoring variable by a second linear mapping; and
wherein the second linear mapping is a null space projection operator of the pseudoinverse of the transposed Jacobian matrix for the robot-permanent reference point.

19. A computer program product, comprising:
a non-transitory computer readable storage medium; and
a program stored on the non-transitory computer readable storage medium that, when executed by a processing unit, causes the processing unit to:
detect joint forces acting in joints of a kinematically redundant robot,
determine an external work force between a robot-permanent reference point and an environment based on the detected joint forces,
determine, based on the detected joint forces, a further monitoring variable which is at least substantially independent of an external force acting on the robot-permanent reference point,
monitor the determined external work force and the determined further monitoring variable, and
control the robot based on at least one of the determined external work force or the determined further monitoring variable.

20. A robot, comprising:
a plurality of joints; and
a control configured for executing the method of claim 1 , the control comprising:
a detection means for detecting joint forces,
a processing means for determining the external work force and further monitoring variable, and
a monitoring means for monitoring the determined external work force and the determined further monitoring variable.

21. The robot of claim 20 , comprising at least seven joints.

Assignees

• Kuka Lab Gmbh
• Kuka Roboter Gmbh

Inventors

• Ueberle Marc-Walter

Classifications

• B25J9/1674 Primary

  characterised by safety, monitoring, diagnostic · CPC title

• G05B2219/39319

  Force control, force as reference, active compliance · CPC title

• G05B2219/40367

  Redundant manipulator · CPC title

• Y10S901/28

  Joint · CPC title

• G05B2219/37624

  Detect collision, blocking by measuring change of velocity or torque · CPC title