Operation teaching method and apparatus for industrial robot

• US 4,613,943 A
• Filed: 04/12/1984
• Issued: 09/23/1986
• Est. Priority Date: 04/13/1983
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Miyake, Norihisa, Tsuchihashi, Akira, Hashimoto, Yasuhiro, Maruyama, Yutaka, Fujiwara, Osamu
• Primary Examiner(s): Ruggiero, Joseph
• Application Number:
  US06/599,472
• Time in Patent Office: 894 Days
• Field of Search: 364/513, 364/191-193, 364/474, 364/478, 318/568, 901/1-7, 901/41, 901/42, 901/50, 414/730
• US Class Current: 700/251
• CPC Class Codes: B23K 9/12 Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
• CPC Class Codes: G05B 19/42 Recording and playback systems, i.e. in which the programme is recorded from a cycle of operations, e.g. the cycle of operations being manually controlled, after which this record is played back on the same machine
• CPC Class Codes: G05B 2219/36461 Teach for each next similar fixture, piece only some reference points
• CPC Class Codes: G05B 2219/36503 Adapt program to real coordinates, software orientation
• CPC Class Codes: G05B 2219/45083 Manipulators, robot

Abstract

An operation teaching method and apparatus for an industrial robot adapted to be successively moved to and set at different positions along an objective structure to conduct a predetermined operation on working objects of the same configuration on the objective structure to which objects the different positions correspond, respectively. The data taught at an initial position is corrected through a coordinate transformation between a coordinate system fixed on a working object and a coordinate system assumed on the robot, and the corrected data are reproduced and used as the operation data for the second and the following working positions.

Claims

1. An operation teaching method for an industrial robot adapted to be successively moved to and set at different positions along an objective structure to conduct a predetermined operation on working objects of the same configuration on the objective structure to which objects said different positions correspond, respectively, said method comprising:

teaching, when said industrial robot is set at a first position corresponding to a first working object, positions of base references and a locus of the robot operation assumed on said first working object, and storing such information as coordinate values given in terms of a first robot coordinate system assumed in said robot set in said first position;

teaching, when said industrial robot is set at a second position corresponding to a second working object, positions of comparison reference assumed on said second working object at positions corresponding to said base references, and storing such information as coordinate values given in terms of a second robot coordinate system assumed in said industrial robot set at said second position;

computing, by using the coordinate values of said base references on said first robot coordinate system, correlation information concerning a base relationship between said first robot coordinate system and a workpiece coordinate system which is determined by said base references;

computing, by using the coordinate values of said comparison references on said second robot coordinate system, correlation information concerning a comparison relationship between said second robot coordinate system and said workpiece coordinate system; and

correcting, by using said base relationship and comparison relationship information, the coordinate values representing said locus of the robot operation in terms of said first robot coordinate system to determine coordinate values representing said locus of the robot operation in terms of said second robot coordinate system.

2. An operation teaching method for an industrial robot according to claim 1, wherein said correlation information comprises a transformation matrix having a component corresponding to the amount of translational movement of said second robot coordinate system with respect to said first robot coordinate system, and a component corresponding to the direction cosines of said second robot coordinate system with respect to said first robot coordinate system.

3. An operation teaching method for an industrial robot according to claim 2, wherein said base references and said comparison references include at least three different reference informations as reference informations for correcting the positional relationship between said second working object and said industrial robot, respectively.

4. An operation teaching method for an industrial robot according to claim 3, wherein said three reference informations comprise a first point assumed on each working object, a second point on a straight line assumed on each working object and passing said first point but located at a position different from that of said first point, and a third point which is in a plane containing said straight line but not existing on said straight line.

5. An operation teaching method for an industrial robot according to claim 2, wherein said base references and said comparison references include two different reference informations as reference informations for correcting the positional relationship between said second working object and said industrial robot.

6. An operation teaching method for an industrial robot according to claim 5, wherein said two reference informations comprise a first point assumed on each working object, and a second point on a straight line assumed on each working object and passing said first point but located at a position different from that of said first point.

7. An operation teaching method for an industrial robot according to claim 5, wherein said two reference informations comprise a first point assumed on each working object, and a second point on a straight line assumed on each working object and passing said first point but located at a position different from that of said first point.

8. An operation teaching method for an industrial robot according to any one of claims 4, 6 and 7 wherein the correction of positional relationship between said second working object and said robot is performed by correcting a coordinate transformation including a translational movement in a three-dimentional space and a rotational movement around a vertical axis or a horizontal axis.

9. An operation teaching method for an industrial robot according to claim 2, wherein said base references and said comparison references include one reference information as a reference information for correcting the positional relationship between said second working object and said industrial robot, respectively.

10. An operation teaching apparatus for an industrial robot adapted to be successively moved to and set at different positions along an objective structure to conduct a predetermined operation on working objects of the same configuration on said objective structure to which objects said different positions correspond, respectively, said apparatus comprising:

memory means for storing the content of a robot operation on the working objects taught to said industrial robot;

first computing means for obtaining correlation information between coordinate values of base references assumed on a first working object and coordinate values of comparison references assumed on a second working object, said coordinate values of the base references being stored in said memory means in terms of a first robot coordinate system assumed on said industrial robot set at a first position corresponding to said first working object, said coordinate values of the comparison references being stored in said memory means in terms of a second robot coordinate system assumed on said industrial robot in a second position corresponding to said second working object; and

second computing means for conducting, using said correlation information, correcting computation of coordinate values representing the taught operation of the robot and stored in said memory means in terms of said first robot coordinate system to determine coordinate values representing said taught operation in terms of said second robot coordinate system.

11. An operation teaching apparatus for an industrial robot according to claim 10, wherein said first computing means includes first means for computing a first transformation matrix which represents correlation information between said first robot coordinate system and a first working object coordinate system assumed on said first working object with respect to said base references;

and

second means for computing a second transformation matrix which represents correlation information between said second robot coordinate system and a second working object cordinate system assumed on said second working object with respect to said comparison references, and

third means for computing, using said first and second transformation matrices, a third transformation matrix for correcting the positional error of said second position with respect to said first position.

12. An operation teaching apparatus for an industrial robot according to claim 11, wherein said second computing means includes

means for conducting, using values of said third transformation matrix, a correcting computation of said coordinate values representing the taught operation of the robot and stored in terms of said first robot coordinate system into the coordinate values representing the taught operation and given in terms of said second robot coordinate system.

13. An operation teaching apparatus for an industrial robot according to claim 12, wherein said base references and said comparison references includes three different reference informations as reference informations for correcting the positional relationship between said second working object and said industrial robot, respectively.

14. An operation teaching apparatus for an industrial robot according to claim 13, wherein said three reference informations comprise a first point assumed on each working object, a second point on a straight line assumed on each working object and passing said first point but located at a position different from that of said first point, and a third point which is in a plane containing said straight line but not existing on said straight line.

15. An operation teaching apparatus for an industrial robot according to claim 12, wherein said base references and said comparison references includes two different reference informations as reference informations for correcting the positional relationship between said second working object and said industrial robot.

16. An operation teaching apparatus for an industrial robot according to claim 15, wherein said two reference informations comprise a first point assumed on each working object, and a second point on a straight line assumed on each working object and passing said first point but located at a position different from that of said first point.

17. An operation teaching apparatus for an industrial robot according to claim 15, wherein said two reference informations comprise a reference plane passing through a specific axis of each working object coordinate system parallel to one of the axis of each robot coordinate system, and a reference point assumed on said reference plane.

18. An operation teaching apparatus for an industrial robot according to claim 12, wherein said base references and said comparison references include one reference information as a reference information for correcting the positional relationship between said second working object and said industrial robot.