MULTI-ARM ROBOT SYSTEM INTERFERENCE CHECK VIA THREE DIMENSIONAL AUTOMATIC ZONES

• US 20090326711A1
• Filed: 05/21/2008
• Published: 12/31/2009
• Est. Priority Date: 05/21/2008
• Status: Active Grant

• Current Assignee: Fanuc Robotics America Incorporated (Fanuc Corporation)
• Original Assignee: Fanuc Robotics America Incorporated (Fanuc Corporation)
• Inventors: Tao, Jianming, Chang, Tien L., McGee, H. Dean, Wong, Ho Cheung, Tsai, Jason
• Granted Patent: US 8,315,738 B2
• Time in Patent Office: Days
• US Class Current: 700/248
• CPC Class Codes: B25J 9/1666 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/39135 For multiple manipulators operating at same time, avoid collision
• CPC Class Codes: G05B 2219/40442 Voxel map, 3-D grid map
• CPC Class Codes: G05B 2219/40492 Model manipulator by spheres for collision avoidance

Abstract

A system and method for controlling avoiding collisions in a workcell containing multiple robots is provided. The system includes a sequence of instructions residing on a controller for execution thereon to perform an interference check automatic zone method. The interference check automatic zone method includes the steps of: determining a first portion of a common space that is occupied during a movement of a first robot along a first programmed path; determining a second portion of the common space that is occupied during a movement of a second robot along a second programmed path; comparing the first portion and the second portion to determine if an overlap exists therebetween; and moving the first robot and the second robot in response to whether or not the overlap exists.

Claims

1. A system for controlling collision avoidance in a workcell containing multiple robots, comprising:

at least one controller adapted for connection to a source of power;

a sequence of instructions residing on the controller for execution thereon, the sequence of instructions including an interference check automatic zone method;

a first robot in communication with and controlled by one of the at least one controllers; and

a second robot in communication with and controlled by one of the at least one controllers, wherein the first robot and the second robot are configured to selectively occupy at least one common space within the workcell.

2. The system of claim 1, wherein the sequence of instructions comprises the steps of:

determining a first portion of the common space that is occupied during a movement of the first robot along a first programmed path;

determining a second portion of the common space that is occupied during a movement of a second robot along a second programmed path;

comparing the first portion to the second portion of the common space to determine if an overlap exists between the first portion and the second portion; and

one of;

moving only one of the first robot along the first programmed path and the second robot along the second programmed path, if there is overlap between the first portion and the second portion of the common space; and

moving the first robot along the first programmed path and moving the second robot along the second programmed path, if there is no overlap between the first portion and the second portion of the common space.

3. The system of claim 1, further comprising a teaching device in electrical communication with the at least one controller and configured to graphically represent the first robot, the second robot, the first portion of the common space, and the second portion of the common space for an operator, wherein the sequence of instructions are generated through the use of the teaching device to jog the robot.

4. The method of claim 1, wherein the first robot and the second robot are attached to a single robot controller.

5. The method of claim 1, wherein the first robot is attached to a first robot controller and the second robot is attached to a second robot controller.

6. The method of claim 1, wherein the workcell includes a plurality of common spaces, the first robot and the second robot configured to selectively occupy each of the common spaces.

7. A method of avoiding collisions in a workcell containing multiple robots, the method comprising the steps of:

providing at least one common space within the workcell that is selectively occupied by a first robot and a second robot;

determining a first portion of the common space that is occupied during a movement of the first robot along a first programmed path;

determining a second portion of the common space that is occupied during a movement of a second robot along a second programmed path;

comparing the first portion and the second portion to determine if an overlap exists therebetween; and

one of;

moving only one of the first robot along the first programmed path and the second robot along the second programmed path, if there is overlap between the first portion and the second portion of the common space; and

moving the first robot along the first programmed path and moving the second robot along the second programmed path, if there is no overlap between the first portion and the second portion of the common space.

8. The method of claim 7, wherein at least one of the common space, the first portion, and the second portion is represented by a voxel model.

9. The method of claim 7, further comprising the step of determining an unoccupied portion of the common space after at least one of the first robot has moved along the first programmed path and the second robot has moved along the second programmed path.

10. The method of claim 9, further comprising the step of releasing the unoccupied portion of the common space for a further programmed path.

11. The method of claim 7, further comprising the step of transferring the coordinates of at least one of the first portion and the second portion to at least one controller, the controller configured to generate a voxel model from the coordinates.

12. The method of claim 7, wherein a robot controller conducts the steps of determining if the overlap exists between the first portion and the second portion of the common space.

13. The method of claim 7, wherein the movement of one of the first robot and the second robot if overlap exists is determined by a priority value.

14. The method of claim 7, wherein one of the first programmed path and the second programmed path is provided by a single motion statement in a sequence of instructions having multiple motion statements.

15. The method of claim 7, wherein one of the first programmed path and the second programmed path is provided by a plurality of motion statements.

16. The method of claim 7, wherein at least one of the first portion and the second portion of the common space includes a space occupied by at least one of a tooling attached to at least one of the first robot and the second robot and a dressout attached to at least one of the first robot and the second robot.

17. The method of claim 7, wherein the step of determining the overlap also includes determining overlap with a third portion of the common space occupied by an obstacle.

18. The method of claim 7, wherein at least one of the first robot and the second robot having a plurality of programmed paths, the method further comprising the step of analyzing the plurality of programmed paths for the existence of overlap causing a deadlock condition.

19. The method of claim 18, wherein an operating sequence of the plurality of programmed paths is adjusted to militate against the deadlock condition.

20. A method of avoiding collisions in a workcell containing multiple robots, the method comprising the steps of:

providing at least one common space within the workcell that is selectively occupied by a first robot and a second robot, the first robot and the second robot in communication with at least one controller;

determining a first portion of the common space that is occupied during a movement of the first robot along a first programmed path;

representing the first portion as a first voxel model on the controller;

determining a second portion of the common space that is occupied during a movement of a second robot along a second programmed path;

representing the second portion as a second voxel model on the controller;

comparing the first voxel model and the second voxel model to determine if an overlap exists therebetween;

one of;

moving only one of the first robot along the first programmed path and the second robot along the second programmed path, if there is overlap between the first voxel model and the second voxel model of the common space, and

moving the first robot along the first programmed path and moving the second robot along the second programmed path, if there is no overlap between the first voxel model and the second voxel model of the common space;

determining an unoccupied portion of the common space after at least one of the first robot has moved along the first programmed path and the second robot has moved along the second programmed path; and

releasing the unoccupied portion of the common space for a further programmed path.