Compliant end of arm tooling for a robot

• US 8,606,398 B2
• Filed: 08/29/2008
• Issued: 12/10/2013
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Research Ltd. (ABB Limited)
• Inventors: Eakins, William, Fuhlbrigge, Thomas A., Martinez, Carlos, Chen, Heping, Rossano, Gregory
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Edwards, Jerrah
• Application Number:
  US13/061,245
• Publication Number:
  US 20110211938A1
• Time in Patent Office: 1,929 Days
• Field of Search: 414/738, 744/900.5, 279/4.03, 403/40, 403/133, 403225-228, 700/117, 700/256, 700/900
• US Class Current: 700/245
• CPC Class Codes: B25J 13/085 Force or torque sensors B25J13/082, B25J13/084 take precedence
• CPC Class Codes: B25J 15/0019 End effectors other than grippers
• CPC Class Codes: B25J 15/0052 multiple gripper units or multiple end effectors
• CPC Class Codes: B25J 15/04 with provision for the remote detachment or exchange of the head or parts thereof
• CPC Class Codes: B25J 17/0208 Compliance devices
• CPC Class Codes: B25J 9/1687 Assembly, peg and hole, palletising, straight line, weaving pattern movement
• CPC Class Codes: B25J 9/1694 characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
• CPC Class Codes: G05B 2219/39574 Passive compliant hand, wrist
• CPC Class Codes: G05B 2219/40035 Shake grasped parts for dropping excess entangled parts back into pin
• CPC Class Codes: G05B 2219/40053 Pick 3-D object from pile of objects
• CPC Class Codes: G05B 2219/40537 Detect if robot has picked up more than one piece from bin; interlocked parts
• CPC Class Codes: Y10T 74/20329 Joint between elements

Abstract

A robot (12) is used to pick parts from a bin (40 in FIG. 1). The robot has a compliant apparatus (42) and one or more tools are connected to the apparatus to perform the picking. The compliant apparatus has mechanisms for monitoring and/or controlling its compliance. The compliant apparatus can have various embodiments. Force sensing can be used during removal of grasped parts from the bin to determine the force exerted on the picking tool (s). The signal indicative of the exerted force can be used by the robot controller to determine the weight of the parts that may be held by the picking tool(s). The robot has one or more devices (FIG. 16, 17) which can be the picking tool to stir the parts in the bin.

Claims

1. A robot for picking one or more parts randomly distributed in a bin comprising:

a moveable arm;

a computing device connected to said robot for controlling motion of said moveable arm; and

a compliant part picking apparatus connected to said moveable arm comprising;

at least one rigid component connected to said moveable arm;

a tool connected to said rigid component, said tool for picking one or more of said parts from said bin; and

at least one compliant component having at least one degree of freedom connected to said at least one rigid component, said compliant component comprising;

a gas filled device whose compliance depends on the pressure of said gas in said gas filled device; and

apparatus to monitor and/or control said gas pressure.

2. The robot of claim 1 wherein said computing device upon determining that one or more of said randomly distributed parts in said bin can be picked by said tool causes said robot moveable arm to move said tool to grasp said one or more pickable parts.

3. The robot of claim 1 wherein said computing device upon determining that said tool has a collision with said bin or said pickable parts while attempting to grasp said one or more pickable parts causes said apparatus to control said gas pressure in said gas filled device to release said gas pressure and said moveable arm to move said tool away from away from the location of said collision.

4. The robot of claim 1 further comprising a tool mounted on said robot for stirring one or more of said one or more randomly distributed parts in said bin when said computing device determines that a predetermined event has occurred.

5. The robot of claim 1 wherein said computing device causes said tool to stir one or more of said one or more randomly distributed parts in said bin upon the occurrence of a predetermined event.

6. The robot of claim 1 further comprising a sensor to monitor the force exerted during removal of one or more parts grasped by said tool from said bin and sending a signal to said computing device indicative of said exerted force.

7. The robot of claim 6 wherein said computing device causes said robot to search for a direction to remove said one or more picked parts that has an exerted force that is less than said predetermined limit when said computing device has determined that said exerted force exceeds a predetermined limit.

8. The robot of claim 7 wherein said computer device causes said tool to release said one or more picked parts after said computing device determines that a predetermined search limit has been reached in searching for a direction to remove said one or more picked parts from said bin without exceeding said predetermined limit for said exerted force.

9. The robot of claim 7 wherein said computing device causes said robot to release said one or more picked parts when said robot cannot find a direction to remove said picked parts that has an exerted force that is less than said predetermined limit.

10. The robot of claim 6 wherein said computing device determines from said signal from said force exerted monitoring sensor if the weight held by said tool is more than the weight of one part.

11. The robot of claim 10 wherein after said computing device has determined that the weight held by said tool is more than the weight of one part said computing device causes said tool to be moved over said bin in a manner designed to encourage all but one of said picked parts to be freed from said tool and dropped back into said bin.

12. The robot of claim 11 wherein after said computing device has determined that the weight held by said tool is more than the weight of one part said computing device determines if a predetermined limit of attempts for said tool to drop parts picked by said tool has been reached.

13. The robot of claim 10 wherein after said computing device has determined that the weight held by said tool is more than the weight of one part said computing device causes said tool to release all of said picked parts into said bin.

14. The robot of claim 12 wherein after said predetermined limit is reached said computing device causes said tool to release all of said picked parts into said bin.

15. The robot of claim 4 further comprising a force sensor for sending a signal to said computing device indicative of said stirring tool contacting one or more of said randomly distributed parts in said bin when stirring is performed.

16. The robot of claim 5 further comprising a force sensor for sending a signal to said computing device indicative of said tool contacting one or more of said randomly distributed parts in said bin when stirring is performed.