Event-based redundancy angle configuration for articulated-arm robots

Patent metadata

Field	Value
Publication number	US-9616564-B2
Application number	US-201514930529-A
Country	US
Kind code	B2
Filing date	Nov 2, 2015
Priority date	Nov 7, 2014
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

The invention relates to a method and a system for controlling a robot, which has at least one redundant degree of freedom. The method according to the invention prevents the robot from colliding with its surrounding environment and/or from getting into an inconvenient position as a result of its redundancy, and does so without causing any disadvantageous displacement of the tool center point.

First claim

The invention claimed is:

1. A method for controlling a hand-guided multi-axle manipulator, in particular an articulated-arm robot, the axes of which are equipped with sensors to register the torques acting on the axes and the positions of a plurality of joints of the multi-axle manipulator, wherein the manipulator has at least one redundant degree of freedom, and wherein the manipulator has a tool center point, which includes the following method steps performed by a control device:
defining, for at least one of the plurality of joints of the manipulator, a range in which the joint of the manipulator can move freely according to the overall movement of the manipulator;
determining according to a position registered by one of the sensors whether the joint has reached a limit of the range defined for the joint as a tool center point of the manipulator is guided by an operator; and
adjusting movement of the manipulator in response to the determination that the joint has reached the limit of the range defined for the joint, so that a movement of the joint through the limit is counteracted, without the tool center point of the robot being displaced as a result of the counteraction.

2. The method according to claim 1 , wherein the adjustment of the movement comprises at least one of a change in the stiffness of the joints of the manipulator or an application of a force.

3. The method according to claim 2 , wherein the adjustment of the movement pertains to the one joint which has reached a limit of the range defined for the joint.

4. The method according to claim 3 , wherein the adjustment of the movement does not pertain to any of the other joints.

5. The method according to claim 1 , wherein the manipulator has at least six axes A 1 to A 6 and the adjustment of the movement is a change in the stiffness of the joints of the axes A 3 or A 4 of the manipulator, wherein the joints of the axes A 3 or A 4 —define an elbow joint of the manipulator.

6. The method according to claim 1 , wherein the adjustment of the movement comprises a redirection of the movement of the one joint, which has reached the limit of the range defined for the joint.

7. The method according to claim 1 , wherein the determination of whether the one joint of the manipulator is located outside of the range defined for the joint comprises an identification of rising and/or falling edges of signals produced by the one sensor.

8. The method according to claim 1 , wherein the determination is carried out while the manipulator is guided by the operator in a force-compensated mode.

9. The method according to claim 1 , wherein the adjustment of the movement of the manipulator can be manually triggered, and the adjustment then occurs automatically.

10. A manipulator system, comprising:
a hand-guided multi-axle manipulator the axes of which are equipped with sensors to register the torques acting on the axes and the positions of a plurality of joints of the multi-axle manipulator, wherein the manipulator has at least one redundant degree of freedom and wherein the manipulator has a tool center point, and
a control device,
wherein the control device is configured to:
a) define, for at least one of the plurality of joints of the manipulator, a range in which the joint of the manipulator can move freely according to the overall movement of the manipulator;

b) determine according to a position registered by one of the sensors whether the joint has reached a limit of the range defined for the joint as a tool center point of the manipulator is guided by an operator; and
c) adjust a movement of the manipulator in response to the determination that the joint has reached the limit of the range defined for the joint, so that a movement of the joint through the limit is counteracted, without the tool center point of the robot being displaced as a result of the counteraction.

11. The manipulator system of claim 10 , wherein the hand-guided multi-axle manipulator is an articulated arm robot.

Assignees

• Kuka Roboter Gmbh

Inventors

• Pfaff Bettina

Classifications

• B25J9/1633

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

• Y10S901/04

  Manual lead through · CPC title

• B25J9/06 Primary

  characterised by multi-articulated arms · CPC title

• B25J9/1674

  characterised by safety, monitoring, diagnostic · CPC title

• B25J9/1666

  Avoiding collision or forbidden zones · CPC title