Pathcorrection for an industrial robot

1. A method for an industrial robot to increase accuracy in movements of the robot, the method comprising:

forming a first path comprising a plurality of generated positions;

directing a tool supported by the robot to assume the plurality of generated positions;

determining a plurality of observed positions of the tool as the tool is directed to assume the plurality of generated positions;

forming a second path of the observed tool positions; and

determining a correction by a path deviation between the observed positions and the generated positions.

2. The method according to claim 1 , wherein the path deviation is calculated based on a vector from a first position in the first path to a second position in the second path, wherein the first position and the second position lie substantially opposite to each other.

3. The method according to claim 2 , wherein the first position and the second position are extracted from the same path index.

4. The method according to claim 2 , wherein the second position lies in a plane normal to a tangent through the first position.

5. The method according to claim 1 , wherein calculation of the path deviation comprises:

adapting the second path to adopt the same orientation as the first path;

adapting the oriented second path to adopt the same position as the first path; and

adapting the oriented and translated second path to adopt the same shape as the first path.

6. The method according to claim 1 , wherein the path deviation forms the basis for a parameter adjustment for the drive device.

7. The method according to claim 6 , wherein the path deviation is calculated from a mean value of the magnitude of the vectors in an interval, arranged along the first path, around a third position.

8. The method according to claim 7 , wherein the third position comprises a position where the movement of a drive device changes direction.

9. The method according to claim 1 , wherein the first path comprises a circle.

10. The method according to claim 1 , wherein corrections are stated as values.

11. The method according to claim 1 , wherein the path deviation forms the basis of a reference adjustment.

12. The method according to claim 11 , wherein the first path is arranged on the surface of the work object.

13. The method according to claim 1 , wherein the first path is adapted to form a reference path and the second path is adapted to form an outcome path.

14. The method according to claim 1 , wherein the adjusted values form the basis of a new outcome path, whereupon the method is repeated for the new outcome path.

15. Use of a method according to claim 1 for increasing the accuracy of movement in an industrial robot during laser machining.

16. A control system for an industrial robot comprising:

a program module;

an interpreter module;

a trajectory generator;

a module for inverse kinematics;

a servo;

an axis-angle measurer;

a measuring module;

a module for calculation of path deviation, which receives data from the trajectory generator and from the measuring module.

17. The control system according to claim 16 , wherein the measuring module comprises a module for direct kinematics and wherein the control system further comprises a module for parameter adjustment, which receives and machines results from the module for calculating the path deviation.

18. The control system according to claim 16 , wherein the module for calculating the path deviation comprises a binary search method, the control system further comprising:

a friction compensator, via a friction model, receives the result from the calculation of the path deviation.

19. The control system according to claim 16 , wherein the measuring module comprises an external measuring system, the control system further comprising:

a module for adjusting the reference path in the trajectory generator.

20. Use of a control system according to claim 16 for increasing the accuracy of movement in an industrial robot during laser machining.

21. A computer program, comprising:

a computer readable medium; and

instructions recorded on the computer readable medium for influencing a processor to control a robot, for increasing the accuracy in the movements of the robot, the instructions for carrying out the steps of

forming a first path comprising a plurality of generated positions, directing a tool supported by the robot to assume the plurality of generated positions,

determining a plurality of observed positions of the tool as the tool is directed to assume the plurality of generated positions,

forming a second path of the observed tool positions, and

determining a correction by a path deviation between the observed positions and the generated positions.

22. The computer program according to claim 21 , wherein the instructions further comprise:

calculating the path deviation based on a vector from a first position in the first path to a second position in the second path, whereby the second position is adapted to lie in a normal plane to a tangent through the first position.

23. The computer program according to claim 21 , wherein the instructions further comprise:

carrying out the calculation of the path deviation in a first step, in which the second path is adapted to adopt the same orientation as the first path, a second step, in which the thus oriented second path is adapted to adopt the same position as the first path, and a third step, in which the thus oriented and translated second path is adapted to adopt the same shape as the first path.

24. The computer program according to claim 21 , provided at least partly over a network such as the Internet.

25. A method to increased accuracy in movements of an industrial robot, the method comprising:

forming a predefined path comprising a plurality of generated positions;

directing a tool supported by the robot to assume the plurality of generated positions;

determining a plurality of observed positions of the tool as the tool is directed to assume the plurality of generated positions;

forming an actual tool path of the observed tool positions;

determining a path deviation between the actual tool path and the predefined path; and

determining at least one correction that will result in bringing the actual tool path closer to the predefined path.

26. The method according to claim 25 , wherein the correction adjusts at least one of an orientation, position and shape of the actual tool path.