Method for correcting teaching points for welding robot and welding robot system employing the same

• US 6,452,134 B2
• Filed: 12/05/2000
• Issued: 09/17/2002
• Est. Priority Date: 02/11/2000
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hong, Sung-jin
• Primary Examiner(s): Elve, M. Alexandra
• Assistant Examiner(s): Kerns, Kevin P.
• Application Number:
  US09/729,164
• Publication Number:
  US 20010013511A1
• Time in Patent Office: 651 Days
• Field of Search: 219/124.34, 219/125.1, 901/42, 901/3, 901/9, 901/10
• US Class Current: 219/124.34
• CPC Class Codes: B23K 20/004 Wire welding
• CPC Class Codes: B23K 9/1278 Using mechanical means
• CPC Class Codes: G05B 19/4083 Adapting programme, configuration
• CPC Class Codes: G05B 2219/36504 Adapt program to real coordinates, shape, dimension of tool, offset path
• CPC Class Codes: G05B 2219/37413 By conductivity, short circuit between tool, probe and metallic surface
• CPC Class Codes: G05B 2219/45104 Lasrobot, welding robot
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48 of an individual wire connector
• CPC Class Codes: H01L 2224/78 Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 24/78 Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01004 Beryllium [Be]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01015 Phosphorus [P]
• CPC Class Codes: H01L 2924/01023 Vanadium [V]
• CPC Class Codes: H01L 2924/01027 Cobalt [Co]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01039 Yttrium [Y]
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

A method for correcting a preset locus of a teaching point for a welding robot having a touch sensor, includes the steps of positioning a workpiece on a welding jig, performing a touch-sensor tracking for the workpiece relative to reference coordinate axes, calculating a displacement of the workpiece through the touch-sensor tracking, and obtaining a new locus of the teaching point based on a transformation matrix generated on the basis of the displacement. With these steps, the teaching points are correctly updated by a touch sensor tracking without an additional equipment for optional sensor tracking, such as laser sensors and arc sensors.

Claims

1. A method for correcting a locus of a teaching point for a welding robot having a touch sensor, comprising the steps of:

mounting a workpiece to a welding jig;

establishing a preset locus of at least one teaching point between an initial welding point and a terminating welding point;

setting at least one detection point defined as a preset locus at said workpiece;

touch-sensing the detection point at said workpiece;

identifying a sensed locus of the detection point detected by the touch-sensing;

generating a transformation matrix based on a difference between the preset locus of the detection point and the sensed locus of the detection point; and

obtaining a new locus of the teaching point based on the transformation matrix.

2. The method according to claim 1, wherein the step of obtaining the new locus of the teaching point includes the step of calculating the new locus of the teaching point by multiplying the preset locus of the teaching point by the transformation matrix.

3. The method according to claim 1, wherein the touch sensor is comprised of a welding wire, provided at an end part of a welding torch.

4. The method according to claim 2, wherein the touch sensor is comprised of a welding wire, provided at an end part of a welding torch.

5. The method according to claim 1, the step of identifying comprising the steps of:

transferring a datum obtained by the step of touch-sensing from a touch-sensing module to a motion control module;

calculating the sensed locus of the detection point based on the datum; and

transferring the calculated datum of the sensed locus of the detection point from the motion control module to a main control module.

6. The method according to claim 1, wherein said preset locus of said detection point is defined as a height of the fixed workpiece.

7. The method according to claim 1, wherein said preset locus of the teaching point is defined as a coordinate of a reference coordinate system.

8. The method according to claim 7, wherein said reference coordinate system is based on three-dimensional orthogonal axes.

9. The method according to claim 7, wherein said reference coordinate system is a cylindrical coordinate system.

10. The method according to claim 7, wherein said reference coordinate system is a polar coordinate system.

11. The method according to claim 1, wherein the step of touch-sensing is performed according to predetermined reference values including directions of torches, traveling directions of welding torches, and an initial and a terminating traveling points of the welding torches, and said predetermined reference values are represented in vectors.

12. A welding robot system comprising:

a welding jig supporting a workpiece to be welded;

a welding robot performing a welding operation to the workpiece and having a touch sensor; and

a controller storing a preset locus of a teaching point and a preset locus of a detection point, said controller identifying a sensed locus of the detection point detected by touch-sensing the workpiece mounted to the welding jig through the touch sensor, said controller calculating a difference between the preset locus of the detection point and the sensed locus of the detection point, said controller generating a transformation matrix based on the difference, said controller obtaining a new locus of the teaching point based on the transformation matrix, said controller controlling the welding robot based on the new locus of the teaching point.

13. The system according to claim 12, the controller calculating the new locus of the teaching point by multiplying the teaching point by the transformation matrix.

14. The system according to claim 12, wherein the touch sensor is comprised of a welding wire, provided at an end part of the welding torch.

15. The system according to claim 13, wherein the touch sensor is comprised of a welding wire, provided at an end part of the welding torch.

16. The system according to claim 12, said controller further comprising a teaching pendant, said teaching pendant teaching welding parameters.

17. The system according to claim 16, said controller comprising:

a main control module to perform the welding operation;

a motion control module for controlling traveling paths of the welding robots; and

a touch-sensing module for touch-sensing the workpiece.

18. The system according to claim 17, said controller performing a motion thread and a touch thread simultaneously by said motion control module and said touch sensing module.

19. A method for correcting a preset locus of a teaching point for a welding robot having a touch sensor, comprising the steps of:

positioning a workpiece on a welding jig;

performing a touch-sensor tracking for said workpiece relative to reference coordinate axes;

calculating a displacement of said workpiece through the touch-sensor tracking;

generating a transformation matrix based on said displacement; and

obtaining a new locus of the teaching point based on said transformation matrix.

20. The method according to claim 19, the step of performing the touch-sensor tracking comprising the steps of:

establishing at least one detection point at said workpiece, said detection point corresponding to a predetermined reference value; and

touch-sensing the workpiece according to the predetermined reference value.

21. The method according to claim 20, the step of calculating the displacement comprising the steps of:

identifying a sensed locus obtained by touch-sensing the workpiece; and

calculating a deviation between said predetermined reference value and said sensed locus.

22. The method according to claim 21, the step of identifying comprising the steps of:

transferring data obtained by the touch-sensor tracking from a touch-sensing module to a motion control module;

calculating the sensed locus of the detection point based on the data, said sensed locus of the detection point defined as coordinates of a reference coordinate system; and

transferring the calculated data of the sensed locus of the detection point from the motion control module to a main control module.

23. The method according to claim 20, wherein said detection point is for detecting a height of the fixed workpiece.

24. The method according to claim 20, said detection point comprising three points for detecting a position in reference three-dimensional orthogonal axes.

25. The method according to claim 19, the step of obtaining the new locus of the teaching point comprising the step of multiplying the preset locus of the teaching point by the transformation matrix.

26. The method according to claim 19, said touch sensor comprising a welding wire, said touch sensor provided at an end part of a welding torch.