Method and apparatus for controlling an obstacle avoiding robot

• US 5,357,598 A
• Filed: 09/18/1992
• Issued: 10/18/1994
• Est. Priority Date: 12/27/1988
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yasuhara, Masateru, Ishihara, Katsumi
• Primary Examiner(s): MacDonald, Allen R.
• Assistant Examiner(s): DAVIS, GEORGE B
• Application Number:
  US07/946,791
• Time in Patent Office: 760 Days
• Field of Search: 395/90, 395/82, 395/92, 901/3
• US Class Current: 700/255
• CPC Class Codes: B25J 9/1676 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/34388 Detect correct moment, position, advanced, delayed, then next command
• CPC Class Codes: G05B 2219/36031 Programming in assembler, machine or high level language
• CPC Class Codes: G05B 2219/39084 Parts handling, during assembly
• CPC Class Codes: G05B 2219/39088 Inhibit movement in one axis if collision danger
• CPC Class Codes: G05B 2219/40397 Programming language for robots, universal, user oriented
• CPC Class Codes: G05B 2219/41275 Two axis, x y motors controlled simultaneous, no contouring, quick move at 45-degrees
• CPC Class Codes: G05B 2219/49143 Obstacle, collision avoiding control, move so that no collision occurs

Abstract

There are provided method and apparatus for controlling a robot, in which when the robot is continuously controlled in different directions such that from the movement in the horizontal direction to the movement in the vertical direction, the movements in the horizontal and vertical directions from a predetermined position are executed in parallel during the movement in the horizontal direction. In the method, target movement positions in the horizontal and vertical directions are input, a first distance which is necessary to move the robot in only the vertical direction is input, and the predetermined position is determined on the basis of the target movement positions in the horizontal and vertical directions and the first distance. The movements in the horizontal and vertical directions include the equal acceleration motion and the equal deceleration motion. With this method, the operator can easily perform the programming and teaching of the robot such that the robot can reach a desired final target position while avoiding obstacles without colliding therewith in the shortest time.

Claims

1. A method of controlling a robot so as to prevent coming into touch with an obstacle, comprising the steps of:

continuously controlling the robot from a movement in a first direction to a movement in a second direction perpendicular to the first direction, and

concurrently executing the movements in the first and second directions from a predetermined position in the movement in the first direction,

wherein the predetermined position is determined by;

a) inputting a target movement position in the first direction;

b) inputting a target movement position in the second direction;

c) inputting a first distance which is necessary to execute the movement in only the second direction, the first distance being necessary to prevent coming into touch with the obstacle; and

d) calculating said predetermined position on the basis of the target movement in the first direction, the target movement in the second direction and the first distance which were input in said steps a), b), and c).

2. A method according to claim 1, wherein said first direction is a horizontal direction and said second direction is a vertical direction.

3. A method according to claim 1, wherein in said step d), said predetermined position is set to a position which is preceding from said target movement position in the first direction by only a second distance of the robot which moves in the first direction for a period of time from the start of the movement in the second direction to the arrival at a head position of the first distance.

4. A method according to claim 1, wherein the movements in the first and second directions include an equal acceleration motion and an equal deceleration motion.

5. A method according to claim 4, wherein periods of time of said equal acceleration motion and said equal deceleration motion are equal.

6. A method according to claim 1, wherein said first distance relates to a length of the obstacle in the second direction.

7. An apparatus for controlling a robot so as to prevent coming into touch with an obstacle, in which when the robot is continuously controlled from a movement in a first direction to a movement in a second direction perpendicular to the first direction, the movements in the first and second directions are executed concurrently from a predetermined position in the movement in the first direction, comprising:

a first position determination control unit in the first direction;

a second position determination control unit in the second direction for controlling independently of the first direction; and

arithmetic operating means for calculating a period of time from the start of the movement in the second direction to arrival at the head position of a first distance, which is necessary to prevent coming into touch with the obstacle, and at which it is necessary to execute only a moving motion in the second direction in response to a target position in the movement in the first direction, a target position in the movement in the second direction, and said first distance and, said arithmetic operating means, further, being operative to calculate a position which precedes the target position in the movement in the first direction by only the movement distance in the first direction in said period of time,

wherein said second position determination control unit is operative to set the position that precedes the target position to said predetermined position and to start a control in the second direction when the robot has passed the predetermined position.

8. An apparatus according to claim 7, wherein said first direction is a horizontal direction and said second direction is a vertical direction.

9. An apparatus according to claim 7, wherein the movements in the first and second directions includes an equal acceleration motion and an equal deceleration motion.

10. An apparatus according to claim 9, wherein periods of time of said equal acceleration motion and said equal deceleration motion are equal.

11. An apparatus according to claim 7, wherein said arithmetic operating means includes means for interpreting commands to designate the target position in the movement in the first direction, the target position in the movement in the second direction, and the first distance.

12. A method of controlling a robot comprising a controlling unit for controllably moving the robot in a first direction and a second direction perpendicular to the first direction, and a command interpreting unit supplying a command of movement start to said controlling unit, wherein movements in the first and second directions are executed concurrently from a predetermined position in the movement in the first direction, comprising the steps of:

a) interpreting, in said command interpreting unit, the command described in a program for moving the robot;

b) calculating, in said command interpreting unit, the predetermined position based on a parameter included in the command;

c) transmitting the command for movement start in the first direction and a data concerned with the predetermined position from the command interpreting unit to said controlling unit;

d) monitoring, in said control unit, a position of the robot during the movement in the first direction; and

responsive to a detection that the robot arrives at the predetermined position, continuing the movement in the first direction and transmitting to said command interpreting unit a signal indicating that the robot has arrived at the predetermined position; and

e) executing, in said command interpreting unit, an interpretation of the command responsive to the signal from said controlling unit.

13. A method according to claim 12, wherein in said step b), said predetermined position is obtained on the basis of a target position in the movement in the first direction, a target position in the movement in the second direction, and a first distance which is necessary to execute the movement in only the second direction.

14. A method according to claim 12, wherein during the step e), said command interpreting unit interprets a command for movement in the second direction, and transmits a command for movement start in the second direction to said control unit.

15. A method according to claim 12, wherein said first direction is a horizontal direction and said second direction is a vertical direction.