Method and device for controlling manipulators

• US 7,571,025 B2
• Filed: 06/01/2005
• Issued: 08/04/2009
• Est. Priority Date: 06/02/2004
• Status: Expired due to Fees

• Current Assignee: KUKA Roboter GmbH (Midea Group Co., Ltd)
• Original Assignee: KUKA Roboter GmbH (Midea Group Co., Ltd)
• Inventors: Bischoff, Rainer
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Marc; McDieunel
• Application Number:
  US11/141,899
• Publication Number:
  US 20050273198A1
• Time in Patent Office: 1,525 Days
• Field of Search: 700/248, 700/245, 700/246, 700/250, 700/251, 700/253, 700/254, 700/255, 700/257, 700/259, 700/260, 700/262, 700/264, 219/121.6, 219/121.63, 219/121.64, 219/124.33, 219/125.1, 318/568.1, 318/568.11, 318/568.13, 318/568.14, 318/568.16, 318/568.21, 318/568.23, 901/4, 901/9, 901/29, 901/42, 901/43, 901/47, 901/50, 744/900.1, 744/900.2, 744/900.5, 744/900.6, 744/790.1, 702/82, 702/467, 414/736, 409/224
• US Class Current: 700/248
• CPC Class Codes: B25J 9/1682 Dual arm manipulator; Coordination of several manipulators
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: G05B 2219/39008 Fixed camera detects reference pattern held by end effector
• CPC Class Codes: G05B 2219/39045 Camera on end effector detects reference pattern
• CPC Class Codes: G05B 2219/39046 Compare image of plate on robot with reference, move till coincidence, camera
• CPC Class Codes: G05B 2219/39051 Calibration cooperating manipulators, closed kinematic chain by alignment
• CPC Class Codes: G05B 2219/39114 Hand eye cooperation, active camera on first arm follows movement of second arm
• CPC Class Codes: G05B 2219/39397 Map image error directly to robot movement, position with relation to world, base not needed, image based visual servoing
• CPC Class Codes: Y10T 74/20207 Multiple controlling elements for single controlled element
• CPC Class Codes: Y10T 74/20305 Robotic arm
• CPC Class Codes: Y10T 74/20311 including power cable or connector
• CPC Class Codes: Y10T 74/20329 Joint between elements
• CPC Class Codes: Y10T 74/20335 Wrist

Abstract

A method for controlling a plurality of manipulators, such as multiaxial or multiaxle industrial robots. At least one manipulator functions as the reference manipulator and is moved in a plurality of preset poses within its working area at which internal position values are determined as first desired poses. For each desired pose, subsequently a first actual pose of the reference manipulator is determined by an external measuring system. Subsequently at least one further manipulator moves up to specific poses of the reference manipulator as second desired poses and for each of these poses an actual pose of the further manipulator is determined by an external measuring system. On the basis of actual-desired deviations between the thus determined desired and actual poses of the two manipulators, subsequently a parameter model for the further manipulator is established and with it it is possible to compensate simultaneously both its own errors and those of the reference manipulator. The method can be used in conjunction with a simplified, improved cooperation between manipulators.

Claims

1. A method for controlling a plurality of multiaxial robots, the method comprising:

a) providing a plurality of multiaxial robots, at least one of said multiaxial robots functioning as a reference manipulator and at least another one of said multiaxial robots functioning as a copying manipulator;

b) moving said reference manipulator into a plurality of predetermined poses within a working area of said reference manipulator, wherein internal position values of said reference manipulator are determined in said working area, said internal position values corresponding to first desired poses;

c) determining a first actual pose of said reference manipulator with a first external measuring system for each of said first desired poses from step b);

d) moving said copying manipulator to second desired poses, said second desired poses corresponding to said first desired poses determined by the reference manipulator, said copying manipulator moving independently from said reference manipulator;

e) determining a second actual pose of said copying manipulator with a second external measuring system for each of said second desired poses in step c); and

f) determining a parameter model for said copying manipulator based on actual-desired deviations between said first desired and said first actual poses of said reference manipulator and said second desired and said second actual poses of the copying manipulator such that said parameter model compensates for errors of said copying manipulator and errors of said reference manipulator.

2. A method according to claim 1, wherein in step d) said copying manipulator advances to the first desired poses of the reference manipulator preset in step b).

3. A method according to claim 1, wherein in step d) said copying manipulator advances to said first actual poses of said reference manipulator determined in step c).

4. A method according to claim 3, wherein said copying manipulator is moved until a pose thereof and the actual pose of the reference manipulator coincide within the framework of the preset deviation tolerances and/or a preset displacement or offset.

5. A method according to claim 4, wherein the movement of said copying manipulator in step d) takes place as a function of the second external measuring system.

6. A method according to claim 1, wherein the operation of the reference manipulator and the copying manipulator takes place substantially simultaneously, the desired and/or actual pose of the reference manipulator being transmitted to the copying manipulator by means of a link, said link comprising a data link.

7. A method according to claim 1, wherein the copying manipulator carries the second external measuring system, so that the second external measuring system is jointly moved by said copying manipulator.

8. A method according to claim 1, wherein a pose determination by the first external measuring system and said second external measuring system takes place optically.

9. A method according to claim 1, wherein said reference manipulator and said copying manipulator are operated in a common working cell.

10. A method according to claim 1, wherein said copying manipulator is operated in a further working cell identical to said reference manipulator working cell.

11. A method according to claim 1, wherein the first desired and actual poses of the reference manipulator are stored following their determination.

12. A method according to claim 11, wherein the reference manipulator and copying manipulator are operated in time-staggered manner, the desired and/or actual poses of the reference manipulator being transmitted in stored form to the copying manipulator.

13. A method according to claim 11, wherein said reference manipulator and said copying manipulator are operated successively in one working cell on the same control device.

14. A method according to one of the preceding claims, wherein initially a first manipulator is selected as the reference manipulator and a second manipulator as the copying manipulator, subsequently the second manipulator functioning as the reference manipulator and a further manipulator functioning as the copying manipulator.

15. A device for improving accuracy characteristics of multiaxial robots, the device comprising:

at least two manipulators comprising a reference robot and a copying manipulator;

at least one control device for moving said reference robot independently from said copying manipulator into predetermined desired poses;

at least one external measuring system, said at least one external measuring system determining reference robot actual poses of said reference robot and manipulator actual poses of said copying manipulator, said reference robot actual poses corresponding to reference robot desired poses of said reference robot, said manipulator actual poses corresponding to copying manipulator desired poses,

a comparator device for determining a deviation between the desired and actual poses of one or more of said reference robot and said copying manipulator; and

a model forming device for determining a parameter model of at least one of said reference robot and said copying manipulator based on said deviation between said copying manipulator desired poses and said manipulator actual poses and said deviation between said reference robot desired poses and said reference robot actual poses.

16. A device according to claim 15, wherein at least one external measuring system is arranged in a stationary manner and operatively connected to a working area of a manipulator.

17. A device according to claim 15, wherein an external measuring system is located on one of said reference robot and said copying manipulator and is movable therewith.

18. A device according to claim 17, wherein the measuring system is a filament or wire measuring system.

19. A device according to claim 15, further comprising an external measuring system, said external measuring system being an optical measuring system.

20. A device according to claim 19, wherein the optical measuring system determines all the degrees of freedom of a pose of said reference robot and said copying manipulator.

21. A device according to claim 19, wherein the external measuring system is a stereo image processing system.

22. A device according to claim 15, further comprising a common working cell for the simultaneous operation of said reference robot and said copying manipulator.

23. A device according to claim 15, further comprising separate working cells for said reference robot and said copying manipulator.

24. A device according to claim 15, further comprising transmission means for transmitting data between said reference robot and said copying manipulator, said data comprising desired and/or actual poses and internal position values.

25. A device according to claim 15, further comprising a storage means for storing at least desired and/or actual poses of one or more of said reference robot and said copying manipulator.

26. A device according to claim 25, further comprising a working cell for the sequential operation of said reference robot and said copying manipulator, said reference robot and said copying manipulator being controlled via the same control device.

27. A method for controlling a plurality of multiaxial robots, the method comprising:

providing a plurality of multiaxial robots comprising a reference manipulator and a copying manipulator;

determining a plurality of first desired poses of said reference manipulator;

moving said reference manipulator to said plurality of first desired poses within a working area of said reference manipulator;

determining a plurality of first actual poses of said reference manipulator via a first external measuring system when said reference manipulator is moved to said plurality of first desired poses, each of said first actual poses being associated with one of said first desired poses;

moving said copying manipulator to a plurality of second desired poses, said second desired poses corresponding to said first desired poses, said copying manipulator moving independently from said reference manipulator;

determining a plurality of second actual poses of said copying manipulator via a second external measuring system when said copying manipulator is moved to said plurality of second desired poses, each of said second actual poses being associated with one of said second desired poses;

determining a reference manipulator deviation between said first desired poses and said first actual poses of said reference manipulator;

determining a copying manipulator deviation between said second desired poses and said second actual poses of said copying manipulator;

creating a parameter model for said copying manipulator based on said reference manipulator deviation and said copying manipulator deviation;

compensating for deviations between said first desired poses and said first actual poses of said reference manipulator and for deviations between said second desired poses and said second actual poses of said copying manipulator by using the parameter model.

28. A method according to claim 27, wherein said copying manipulator is moved until a pose thereof and the actual pose of the reference manipulator coincide within a preset deviation tolerance and/or a preset displacement or offset.

29. A method according to claim 28, wherein said copying manipulator is moved as a function of the second external measuring system.