Robot control method

• US 9,266,238 B2
• Filed: 10/12/2012
• Issued: 02/23/2016
• 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
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): Lin, Abby
• Application Number:
  US13/650,384
• Publication Number:
  US 20130103192A1
• Time in Patent Office: 1,229 Days
• Field of Search: 700245-264, 414/730, 414/742, 901/15, 901/4, 901/6
• US Class Current: 1/1
• 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

Target values for position and orientation of a work point are provided in a robot program, dependent on which the program causes automatic movement of axles of the manipulator by a robot controller connected with the manipulator, to adjust a tool reference point of the manipulator. A robot base is movable via an auxiliary axle. Position values (provided by the robot program) of a planned position and orientation to be occupied by robot base for the tool reference point adjustment are automatically changed so the actual position of the robot base converges on a predetermined reference point, such as the work point or the tool reference point and the auxiliary axle is automatically moved 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 connected to a robot base, said robot manipulator comprising a plurality of manipulator axles, 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:

providing said robot controller with a robot program that causes said robot controller to operate said robot manipulator and said robot base from said robot controller according to the robot program by automatically controlling movement of said manipulator axles and said at least one base axle, to adjust a tool reference point of said robot manipulator dependent on a work point of the 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 robot controller, from said target values, executing said robot program to determine planned values for a planned position and orientation of said robot base to be achieved by controlling movement of said at least one base axle by said robot controller in order to adjust said tool reference point dependent on said work point;

in said robot controller,

automatically changing said planned values, without changing said work point, to changed values of said position and orientation of said robot base, that change said position and orientation of said robot base, relative to said planned position and orientation of said robot base, that is to be occupied by said robot base in order to adjust said tool reference point dependent on said work point,

with said changing being based on said changed values and said target values, to cause said position and orientation of said robot base to converge on a predetermined reference point to cause said position of said robot based relative to said planned orientation and position to be located at a minimized distance from a current position of said tool reference point, and

automatically reverse-calculating 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-calculated axle values.

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

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

4. The 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 position and orientation of said robot base relative to said planned position and orientation to converge on said predetermined reference point.

5. The 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.

6. The 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.

7. The 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.

8. The method as claimed in claim 7 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.

9. The 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.

10. The method as claimed in claim 9 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.

11. The method as claimed in claim 1 comprising:

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

12. The method as claimed in claim 1 comprising:

providing a global 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 global coordinate 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 global coordinate system, dependent on position and orientation of said robot base adjustable by said at least one base axle; and

automatically reverse-calculating 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 global coordinate system.

13. The method as claimed in claim 12 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.

14. The method as claimed in claim 12 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.