Robot capable of generating patterns of movement path

• US 5,600,759 A
• Filed: 07/01/1994
• Issued: 02/04/1997
• Est. Priority Date: 03/20/1989
• Status: Expired due to Term

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Karakama, Tatsuo
• Primary Examiner(s): Davis, George B.
• Application Number:
  US08/270,216
• Time in Patent Office: 949 Days
• Field of Search: 395/80, 395/81, 395/86, 395/87, 395/89, 395/82, 395/97, 395/99, 318/568.13, 901/3
• US Class Current: 700/252
• CPC Class Codes: G05B 19/425 Teaching successive positions by numerical control, i.e. commands being entered to control the positioning servo of the tool head or end effector

Abstract

A robot which is capable of automatically generating movement path patterns based on taught data and in which a data teaching operation associated with pattern generation is simplified and no special data teaching is required even when the pitch between pattern segments is to be changed. During a manual robot operation, when start and end points (P0, Pn) of a spraying pattern which consists of a series of subpatterns, and a first cornering point (P1) of a first subpattern are taught to the robot, taught data representing these three point is stored in a robot control unit, together with a spraying command code and a spraying pitch (d) taught separately. During a playback robot operation, in response to the spraying command code, a vector (A) directed from the start point (P0) to the first cornering point (P1) and a vector (D) directed from the first cornering point (P1) to a second cornering point (P2) are calculated based on the taught data and the pitch. Each time a plasma jet torch reaches one of the start point, first to third cornering points and end point of a subpattern, the end point of a corresponding one of the vector (A), the vector (B), and a vector derived by reversing the vector (A), all having a start point thereof coinciding with the reached point, is determined as a new target position, thereby generating a spraying pattern.

Claims

1. A robot for automatically generating a movement path pattern based on previously taught data, comprising:

first teaching means for teaching only a portion of a plurality of points in a sub-pattern of a movement path pattern, said portion of said plurality of points including a start point, an end point, and one cornering point, said movement path pattern including a plurality of segments each connected to each other to form said movement path pattern;

first storing means for storing said taught start point, end point, and one cornering point as taught data;

second teaching means for teaching a pitch between adjacent and parallel segments of said plurality of segments;

second storing means for storing said taught pitch; and

pattern generating means for automatically generating said movement path pattern based on said stored taught data and said stored taught pitch.

2. A robot according to claim 1, wherein said second teaching means is operable to input a numerical value of the pitch between the segments.

3. A robot according to claim 2, wherein said robot includes a thermal spraying robot having a plasma jet torch.

4. A robot according to claim 1,

wherein said robot includes a tool driven along the movement path pattern,

wherein the movement path pattern comprises a series of identical subpatterns, each of the subpatterns including a first segment connecting a subpattern start point and a first subpattern cornering point, a second segment connecting the first subpattern cornering point and a second subpattern cornering point, a third segment extending parallel to the first segment and connecting the second subpattern cornering point and a third subpattern cornering point, and a fourth segment extending parallel to the second segment and connecting the third subpattern cornering point and a subpattern end point, and

wherein said pattern generating means is operable to calculate first and second vectors corresponding respectively to the first and second segments of each of the subpatterns in dependence upon the taught data stored in said first storing means, and is operable to determine a new target position of the tool using a corresponding one of the first and second vectors when the tool reaches a target position corresponding to one of the subpattern start point and the first to third subpattern cornering points of one of the subpatterns.

5. A robot according to claim 4,

wherein said pattern generating means is operable to determine a first vector end point, as the new target position, of the first vector having a first vector start point coinciding with one of the subpattern start and end points of one of the subpatterns when the tool reaches one of the subpattern start and ends points,

wherein said pattern generating means is operable to determine a second vector end point, as the new target position, of the second vector having a second vector start point coinciding with one of the first and third subpattern cornering points of the one of the subpatterns when the tool reaches one of the first and third subpattern cornering points, and

wherein said pattern generating means is operable to determine a derived vector end point, as the target position, of a vector derived by reversing the first vector and having a derived vector start point coinciding with the second subpattern cornering point of one of the subpatterns when the tool reaches the second subpattern cornering point.

6. A robot according to claim 5, wherein said pattern generating means is operable to calculate, on the basis of the taught data, a first fundamental vector having a fundamental vector start point coinciding with the start point of the movement path pattern and a first fundamental vector end point coinciding with the first subpattern cornering point of a first subpattern of the movement path pattern, a second fundamental vector having a second fundamental vector start point coinciding with a first subpattern cornering point and a second fundamental vector end point coinciding with the end point of the movement path pattern, and a third fundamental vector having a third fundamental vector start point coinciding with the start point of the movement path pattern and a third fundamental vector end point coinciding with the end point of the movement path pattern,

wherein said pattern generating means is operable to calculate a first unit vector whose direction is the same as that of an outer product vector of the first fundamental vector and an outer product vector of the first fundamental vector and the third fundamental vector, and a second unit vector whose direction is the same as that of the second fundamental vector, and

wherein said pattern generating means is operable to calculate the second vector by multiplication of a reciprocal of an inner product of the first and second unit vectors, the pitch, and the second unit vector.

7. A robot according to claim 5, wherein said robot includes a thermal spraying robot having a plasma jet torch.

8. A robot according to claim 5, wherein said robot includes a thermal spraying robot having a plasma jet torch.

9. A robot according to claim 4, wherein said robot includes a thermal spraying robot having a plasma jet torch.

10. A robot according to claim 1, wherein said robot includes a thermal spraying robot having a plasma jet torch.

11. A method for a robot to automatically generate a movement path pattern based on previously taught data, comprising the steps of:

(a) teaching only a portion of a plurality of points in a sub-pattern of a movement path pattern, said portion of said plurality of points including a start point, an end point, and one cornering point, said movement path pattern including a plurality of segments each connected to each other to form said movement path pattern;

(b) storing said taught start point, end point, and one cornering point as taught data;

(c) teaching a pitch between adjacent and parallel segments of said plurality of segments;

(d) storing said taught pitch; and

(e) automatically generating said movement path pattern based on said stored taught data and said stored taught pitch.

12. A method according to claim 11, wherein step c includes the step (f) of receiving as input a numerical value of the pitch between the segments.

13. A method according to claim 11, further comprising the step (g) of driving a tool along the movement path pattern.

14. A method according to claim 13, wherein step (g) includes the substeps of:

(1) calculation of first and second vectors corresponding respectively to a first and a second of the plurality of segments in dependence upon the taught data; and

(2) determining a target position of the tool using a corresponding one of the first and second vectors when the tool reaches one of the subpattern start point and the first to third subpattern cornering points of one of the subpatterns, and

wherein the movement path pattern includes a series of identical subpatterns, each of the subpatterns including a first segment connecting a subpattern start point and a first subpattern cornering point, a second segment connecting the first subpattern cornering point and a second subpattern cornering point, a third segment extending parallel to the first segment and connecting the second subpattern cornering point and a third subpattern cornering point, and a fourth segment extending parallel to the second segment and connecting the third subpattern cornering point and a subpattern end point.

15. A method according to claim 14, wherein step (g) further includes the substeps of:

(3) determining a first vector end point, as a target position of the tool, of the first vector having a first vector start point coinciding with one of the subpattern start and end points of one of the subpatterns;

(4) determining a second vector end point, as a target position of the tool, of the second vector having a second vector start point coinciding with one of the first and third subpattern cornering points; and

(5) determining a derived vector end point, as a target position of the tool, of a vector derived by reversing the first vector and having a derived vector start point coinciding with the second subpattern cornering point.

16. A method according to claim 15, wherein step (g) further includes the substeps of:

(6) calculating, in dependence upon the taught data, a first fundamental vector having a first fundamental vector start point coinciding with the start point of the movement path pattern and a first fundamental vector end point coinciding with a first subpattern cornering point of a first subpattern of the movement path pattern, a second fundamental vector having a second fundamental vector start point coinciding with a first subpattern cornering point and a second fundamental vector end point coinciding with the end point of the movement path pattern, and a third fundamental vector having a third fundamental vector start point coinciding with the start point of the movement path pattern and a third fundamental vector end point coinciding with the end point of the movement path pattern;

(7) calculating a first unit vector whose direction is the same as that of an outer product vector of the first fundamental vector and an outer product vector of the first fundamental vector and the third fundamental vector, and a second unit vector whose direction is the same as that of the second fundamental vector; and

(8) calculating the second vector corresponding to the second segment by multiplication of a reciprocal of an inner product of the first and second unit vectors, the pitch, and the second unit vector.

17. A method according to claim 11, further comprising the step (h) of spraying a workpiece along the movement path pattern.

18. A method according to claim 17, wherein the step (i) includes the step (i) of spraying the workpiece with a plasma jet torch.

19. A robot for automatically generating a movement path pattern based on previously taught data, comprising:

first teaching means for teaching only a portion of a plurality of points in a sub-pattern of a movement path pattern, said portion of said plurality of points including a start point, an end point, and one cornering point, said movement path pattern including a plurality of segments each connected to each other to form said movement path pattern;

first storing means for storing said taught start point, end point, and one cornering point as taught data;

second teaching means for teaching a pitch between segments of said plurality of segments;

second storing means for storing said taught pitch; and

pattern generating means for automatically generating said movement path pattern based on said stored taught data and said stored taught pitch.