ROBOT CONTROL METHOD

• US 20130103192A1
• Filed: 10/12/2012
• Published: 04/25/2013
• Est. Priority Date: 10/13/2011
• Status: Active Grant

• Current Assignee: KUKA Laboratories GmbH (Midea Group Co., Ltd)
• Original Assignee: KUKA Laboratories GmbH (Midea Group Co., Ltd)
• Inventors: Huettenhofer, Manfred
• Granted Patent: US 9,266,238 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: B25J 9/162 Mobile manipulator, movable base with manipulator arm mounted on it
• CPC Class Codes: G05B 19/402 characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/40248 Manipulator on slide

Abstract

In a robot control method, target values of a work point are provided in position and orientation by a robot program, programmatically dependent on which a tool reference point of a manipulator is to be adjusted via automatic movement of axles of the manipulator by a robot controller connected with the manipulator. Based on position values (provided by the robot program) of a planned position and orientation of a robot base adjustable via an auxiliary axle, which position and orientation are to be occupied by the robot base, automatically changing the position values such that the actual position of the robot base that is to be occupied relative to the planned position to be occupied converges on a predetermined reference point, in particular the work point or the tool reference point. The robot controller automatically moves the auxiliary axle to cause the robot base to occupy the position and orientation that correspond to the changed position values.

Claims

1. A robot control method for operating a robot system comprising a robot manipulator and a robot base, said robot manipulator comprising a plurality of manipulator axles at which said robot manipulator is articulated, and said robot base comprising at least one base axle that is different from said manipulator axles, and a computerized robot controller in communication with said robot manipulator and said robot base, said method comprising:

operating said robot manipulator and said robot manipulator and said robot base from said robot controller according to a robot program by automatically controlling movement of said axles of said robot manipulator to adjust a tool reference point of said robot manipulator dependent on a work point of robot program, said work point having a position and an orientation associated therewith, said robot program providing target values for said position and said orientation of said work point;

in said controller, from said target values, executing said robot program to determine planned values for position in orientation of said robot base to be achieved by controlling movement of said at least one base axle by said robot controller;

in said robot controller, automatically changing said planned values, to changed values of said position and orientation of said robot base, to cause an actual position of said robot base that is to be occupied by said robot base relative to said position in said planned values, to converge on a predetermined reference point; and

from said controller, automatically controlling movement of said at least one base axle to cause said robot base to occupy a position and orientation corresponding to the changed values.

2. A method as claimed in claim 1 comprising using said work point as said predetermined reference point.

3. A method as claimed in claim 1 comprising using said tool reference point as said predetermined reference point.

4. A method as claimed in claim 1 comprising:

in said robot controller, assigning a zero point, in said robot program, to said at least one base axle, and automatically changing said planned values for said robot base to said changed values by maintaining said target values and modifying said zero point to cause said actual position of said robot base relative to said planned position to converge on said predetermined reference point.

5. A method as claimed in claim 1 comprising:

in said robot controller, based on said changed values and said target values, automatically reverse-engineering respective axle values for the respective manipulator axles that correspond to said changed values for said robot base, and automatically programming approach values of said tool reference point dependent on said reference point; and

from said robot controller, automatically moving elements of said robot manipulator by adjusting the respective manipulator axles to the reverse-engineered axle values.

6. A method as claimed in claim 1 wherein said reference point is a moving reference point, and comprising:

in said robot program in said robot controller, generating clocked or continuous target values dependent on said moving reference point;

in said robot controller, automatically adapting movements of elements of said robot manipulator by adjusting said manipulator axles to cause a path associated with the work point by the robot program, along which path said tool reference point of said robot manipulator should move, to be maintained during movement of said reference point; and

in said robot controller, maintaining said path of said tool reference point dependent on said movement of said at least one base axle during movement of said work point.

7. A method as claimed in claim 1 comprising, via said robot controller, synchronizing automatic movement of said at least one base axle with movement of said work point or said tool reference point.

8. A method as claimed in claim 1 comprising, in said robot controller, causing automatic movement of said at least one base axle to proceed ahead of a movement of said work point or said tool reference point.

9. A method as claimed in claim 8 comprising, in said robot controller, maintaining a path relative to said work point or said tool reference point along which said tool reference point should move, during movement of said work point by automatically adjusting movements of elements of said robot manipulator by automatically adjusting said manipulator axles.

10. A method as claimed in claim 1 comprising, in said robot controller, causing automatic movement of said at least one base axle to trail a movement of said work point or said tool reference point.

11. A method as claimed in claim 10 comprising, in said robot controller, maintaining a path relative to said work point or said tool reference point along which said tool reference point should move, during movement of said work point by automatically adjusting movements of elements of said robot manipulator by automatically adjusting said manipulator axles.

12. A method as claimed in claim 1 comprising:

in said robot controller, automatically generating said changed values by causing said actual position of said robot base to converge on said tool reference point.

13. A method as claimed in claim 12 comprising, in said robot controller, automatically generating said changed values by causing said actual position of said robot base to be located at a shortest possible distance from a current position of said tool reference point.

14. A method as claimed in claim 1 comprising:

providing a world coordinate system to said robot controller;

providing a position and orientation of a base coordinate system associated with a work piece in coordinates of said world coordinately system to said controller;

providing target values in said base coordinates to said controller;

providing a position and orientation of a robot coordinate system associated with said robot base in coordinates of said world coordinate system, dependent on position and orientation of said robot base adjustable by said at least one base axle; and

automatically reverse-engineering respective axial values of the manipulator axles from the position and orientation of said robot base and said target values for the position and orientation of said tool reference point of said robot manipulator based on a transformation of target values from said base coordinate system into said robot coordinate system via said world coordinate system.

15. A method as claimed in claim 14 comprising modifying the position and orientation of said base coordinate system by automatic movement of an additional base axle, in addition to automatic movement of said at least one base axle.

16. A method as claimed in claim 14 comprising modifying the position and orientation of said work point by automatic movement of an additional base axle, in addition to automatic movement of said at least one base axle.