Operation line searching method and robot/sensor system having operation line searching function

• US 6,321,139 B1
• Filed: 11/30/1998
• Issued: 11/20/2001
• Est. Priority Date: 03/28/1997
• Status: Expired due to Term

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Okuda, Mitsuhiro, Terada, Akihiro
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Marc, McDieunel, Marc, McDieunel
• Application Number:
  US09/194,610
• Time in Patent Office: 1,086 Days
• Field of Search: 700/248, 700/245, 700/249, 700/255, 700/264, 700/116, 700/187, 700/251, 700/254, 700/258, 700/259, 700/193, 700/252, 701/29, 228/102, 414/744.8, 414/591, 414/792, 219/124.34
• US Class Current: 700/248
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05B 2219/37571 Camera detecting reflected light from laser
• CPC Class Codes: G05B 2219/45104 Lasrobot, welding robot
• CPC Class Codes: G05B 2219/49386 Automatic seam, weld line, finding

Abstract

An operation line searching method in which an operation start position is automatically approached and a robot/sensor system having such function of detecting the operation line. A robot having a laser sensor and an operation tool attached to a distal end thereof approaches an operation start position Q1 using various searching motion path patterns (a) to (d). Pattern (a) is determined to avoid an obstacle F or an obstructively-shaped portion G. The path thereof, for example, can be determined by specifying a coordinate axis of a coordinate system w. Patterns (b) and (c) are carried out by teaching, to the robot, data for determining the paths thereof in order. Pattern (d) is carried out in the following manner: an initial parameter <V1>, an angle of rotation and a norm increase factor are specified as parameters, and at the time when incremental travel quantity of a (i+1)th occurrence (i=0, 1, 2, . . . ) Should be obtained, it is obtained by calculating <Vi+1>−<Vi>, where the vector <Vi+1> is obtained from the last obtained vector <Vi>based on the illustrated relationship (the angle of rotation and the norm growth factor).

Claims

1. An operation line searching method for a robot/sensor system having a robot, a robot controller and a sensor mounted on said robot for detecting an operation line of an object of operation, so as to perform a predetermined operation by moving a tool supported by said robot along said operation line based on a signal outputted from said sensor, said method comprising:

determining a search motion for finding a position of said operation line using said sensor by moving said tool closer to a predetermined start position of operation, wherein said search motion includes a component of motion in a direction crossing an extending direction of said operation line in the vicinity of said start point of the operation line;

starting said search motion determined in said determination of said search motion; and

terminating said search motion when said sensor detects a shaping element of said object of operation during said search motion, said shaping element defining said operation line.

2. An operation line searching method according to claim 1, wherein said determination of said search motion includes selecting one search motion path pattern from a plurality of previously prepared search motion path patterns each having a component of motion in a direction crossing an extending direction of said operation line in the vicinity of the start point of said operation line.

3. An operation line searching method according to claim 2, wherein said determination of said search motion includes determining said search motion based upon directions of coordinate axes of a coordinate system set for said robot.

4. An operation line searching method according to claim 2, wherein said determination of said search motion includes determining said search motion based upon an operation taught to said robot.

5. An operation line searching method according to claim 2, wherein said determination of said search motion includes determining said search motion based upon a predetermined calculation process using path pattern describing parameters set for said robot/sensor system.

6. An operation line searching method according to claim 1, wherein said determination of said search motion includes determining said search motion based upon directions of coordinate axes of a coordinate system set for said robot.

7. An operation line searching method according to claim 1, wherein said determination of said search motion includes determining said search motion based upon an operation taught to said robot.

8. An operation line searching method according to claim 1, wherein said determination of said search motion includes determining said search motion based upon a predetermined calculation process using path pattern describing parameters set for said robot/sensor system.

9. A robot/sensor system having a robot, a robot controller and a sensor mounted on said robot for detecting an operation line of an object of operation, so as to perform a predetermined operation by moving a tool supported by said robot along said operation line based on a signal outputted from said sensor, said system comprising:

search motion determining means for finding a position of said operation line using said sensor by moving said tool closer to a predetermined start position of operation, wherein said search motion includes a component of motion in a direction crossing an extending direction of said operation line in the vicinity of said start point of the operation line;

a motion unit to start said search motion; and

means for terminating said search motion when said sensor detects a shaping element of said object of operation during said search motion, wherein said shaping element defines said operation line.

10. A robot/sensor system according to claim 9, wherein said search motion is selected from a plurality of previously prepared search motion path patterns each having a component of motion in a direction crossing an extending direction of said operation line in the vicinity of the start point of said operation line.

11. A robot/sensor system according to claim 10, wherein said search motion is determined based upon directions of coordinate axes of a coordinate system set for said robot.

12. A robot/sensor system according to claim 10, wherein said search motion is determined based upon an operation taught to said robot.

13. A robot/sensor system according to claim 10, wherein to said search motion is determined based upon a predetermined calculation process using path pattern describing parameters set for said robot/sensor system.

14. A robot/sensor system according to claim 9, wherein said 5 search motion is determined based upon directions of coordinate axes of a coordinate system set for said robot.

15. A robot/sensor system according to claim 9, wherein said search motion is determined based upon an operation taught to said robot.

16. A robot/sensor system according to claim 9, Wherein to said search motion is determined based upon a predetermined calculation process using path pattern describing parameters set for said robot/sensor system.

17. An operation line searching method for a robot for detecting an operation line of an object of operation, so as to perform a predetermined operation upon the object, said method comprising:

determining a search motion for finding a position of said operation line by moving a tool attached the robot closer to a predetermined start position of operation, wherein the search motion includes a component of motion in a direction crossing an extending direction of said operation line in the vicinity of said start point of the operation line;

starting said search motion determined in said determination of said search motion; and

terminating said search motion when a sensor attached to the robot detects a shaping element defining said operation line.

18. A robot having a sensor for detecting an operation line of an object of operation, so as to perform a predetermined operation on said object by moving a tool supported by said robot along said operation line based on a signal outputted from said sensor, said robot comprising:

a search motion determining unit to derive a position of said operation line, using said sensor, by moving said tool closer to a predetermined start position of operation, wherein the search motion includes a component of motion in a direction crossing an extending direction of said operation line in the vicinity of said start point of the operation line;

a motion unit to start said search motion; and

a termination unit to terminate said search motion when said sensor detects a shaping element of said object of operation during said search motion, wherein said shaping element defines said operation line pattern describing parameters set for said robot/sensor system.