Robotic arm and control system

• US 20090055024A1
• Filed: 11/13/2007
• Published: 02/26/2009
• Est. Priority Date: 08/24/2007
• Status: Active Grant

• Current Assignee: Elite Engineering Corporation
• Original Assignee: Elite Engineering Corporation
• Inventors: Kay, Robert L.
• Granted Patent: US 8,082,064 B2
• Time in Patent Office: Days
• US Class Current: 700/259
• 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 2219/39008 Fixed camera detects reference pattern held by end effector
• CPC Class Codes: G05B 2219/40623 Track position of end effector by laser beam

Abstract

A robotic arm and control system includes a robotic arm which moves in response to one or more command signals. One or more “active” fiducials are located on the arm, each of which emits its own light. A 3D camera having an associated field-of-view is positioned such that at least one fiducial and a target object to be manipulated are in the FOV. To determine their spatial positions, the arm fiducials are activated and the target object is preferably illuminated with a scanning laser; the camera produces output signals which vary with the spatial locations of the fiducials and target object. A controller receives the output signals and uses the spatial position information as feedback to continuously guide the arm towards the target object. Multiple active fiducials may be employed, each having respective characteristics with which they can be differentiated.

Claims

1. A robotic arm and control system, comprising:

a robotic arm which moves in response to one or more command signals;

one or more fiducials located on said arm, each of said fiducials being an “

active”

fiducial such that each emits its own light;

a 3D sensing device having an associated field-of-view (FOV), positioned such that at least one of said fiducials and a target object to be manipulated with said arm are in said sensing device'"'"'s FOV, said sensing device arranged to produce output signals with which the spatial locations of said at least one of said fiducials and said target object can be determined; and

a controller arranged to receive said output signals from said sensing device and to provide said one or more command signals to said robotic arm, said controller arranged to provide closed loop control of said arm such that said at least one of said fiducials is moved towards said target object.

2. The system of claim 1, wherein said robotic arm includes an effector with which said target object is manipulated, at least one of said active fiducials located on or a known distance from said effector.

3. The system of claim 1, wherein said active fiducials have respective characteristics with which they can be differentiated.

4. The system of claim 1, wherein one or more of said active fiducials emit light which includes at least two different wavelengths.

5. The system of claim 1, wherein one or more of said active fiducials are arranged such that the wavelength of their emitted light changes in a predetermined pattern.

6. The system of claim 1, wherein one or more of said active fiducials emit light that is modulated in a predetermined pattern.

7. The system of claim 1, wherein one or more of said active fiducials are arranged to form a predetermined pattern.

8. The system of claim 1, wherein one or more of said active fiducials comprise light-emitting diodes, incandescent lamps, and/or optical fibers.

9. The system of claim 1, further comprising a means of illuminating said target object.

10. The system of claim 9, wherein said means of illuminating said target object comprises a scanning laser.

11. The system of claim 1, wherein said 3D sensing device is a 3D camera, said controller arranged to:

capture the image in said camera'"'"'s FOV when said active fiducials are not illuminated;

capture the image in said camera'"'"'s FOV when said active fiducials are illuminated; and

subtract the non-illuminated image from the illuminated image and use the resulting image to determine the spatial locations of said fiducials.

12. The system of claim 1, wherein said controller comprises:

an image processing module arranged to;

receive said 3D sensing device'"'"'s output signals;

determine the spatial location of said at least one of said fiducials on said robotic arm; and

determine the spatial location of said target object; and

a servo processing module arranged to;

receive spatial location data for said at least one of said fiducials and said target object from said image processing circuit; and

provide said one or more command signals to said robotic arm such that said controller provides closed loop control of said arm such that said at least one of said fiducials is moved towards said target object.

13. The system of claim 12, wherein said image processing circuit is further arranged to control the operation of said at least one of said fiducials and/or the positioning of said 3D sensing device.

14. The system of claim 12, wherein said active fiducials comprise at least two fiducials, each of which is in said sensing device'"'"'s FOV and emits light having associated characteristics which enables said fiducials to be differentiated, said image processing circuit further arranged to detect and determine the spatial positions of said at least two fiducials.

15. The system of claim 1, further comprising one or more active fiducials located on said target object, said 3D sensing device positioned such that at least one of said fiducials located on said target object is in said sensing device'"'"'s FOV, said sensing device arranged to produce output signals with which the spatial locations of said at least one of said fiducials located on said target object can be determined.

16. The system of claim 1, wherein said target object is held in a fixture, further comprising one or more active fiducials located on said fixture, said 3D sensing device positioned such that at least one of said fiducials located on said fixture is in said sensing device'"'"'s FOV, said sensing device arranged to produce output signals with which the spatial locations of said at least one of said fiducials located on said fixture can be determined.

17. The system of claim 1, further comprising at least one additional robotic arm, each of said additional arms moving in response to one or more command signals and having one or more active fiducials located on said arm.

18. The system of claim 17, wherein said 3D sensing device is positioned such that at least one of said fiducials on each of said arms is in said sensing device'"'"'s FOV, said sensing device arranged to produce output signals with which the spatial locations of said at least one of said fiducials on each of said arms can be determined.

19. The system of claim 17, further comprising at least one additional 3D sensing device, each of said sensing devices positioned such that at least one fiducial on a respective arm and a target object are in said sensing device'"'"'s field-of-view (FOV).

20. The system of claim 1, wherein said 3D sensing device is a 3D camera.

21. A robotic arm and control system, comprising:

a robotic arm which moves in response to one or more command signals;

one or more fiducials located on said arm, each of said fiducials being an “

active”

fiducial such that each emits its own light;

a first 3D sensing device having an associated field-of-view (FOV), positioned such that at least one of said fiducials is in said first sensing device'"'"'s FOV, said first sensing device arranged to produce output signals with which the spatial location of said at least one of said fiducials can be determined;

a second 3D sensing device having an associated FOV, positioned such that at least one target object to be manipulated with said arm is in said second sensing device'"'"'s FOV, said second sensing device arranged to produce output signals with which the spatial location of said target object can be determined; and

a controller arranged to receive said output signals from said sensing devices and to provide said one or more command signals to said robotic arm, said controller arranged to provide closed loop control of said arm such that said at least one of said fiducials is moved towards said target object.

22. A robotic arm and control system, comprising:

a robotic arm which moves in response to one or more command signals;

one or more fiducials located on said arm, each of said fiducials being an “

active”

fiducial such that each emits its own light;

an effector coupled to said arm with which a target object is manipulated, at least one of said fiducials located on or a known distance from said effector;

a means of illuminating said target object;

a 3D camera positioned such that at least one of said fiducials and said target object are in said camera'"'"'s field-of-view (FOV), said camera arranged to produce output signals with which the spatial locations of said at least one of said fiducials and said target object can be determined; and

a controller arranged to receive said output signals from said 3D camera and to provide said one or more command signals to said robotic arm, said controller arranged to provide closed loop control of said arm such that said at least one of said fiducials is moved towards said target object.

23. The system of claim 22, wherein said means of illuminating said target object comprises a scanning laser.

24. A method of controlling a robotic arm, comprising:

activating at least one fiducial located on a robotic arm, each of said fiducials being an “

active”

fiducial such that each emits its own light when activated;

determining the spatial location of at least one fiducial;

determining the spatial location of a target object; and

moving said arm so as to reduce the difference between the spatial locations of said at least one fiducial and said target object, such that said at least one active fiducial is moved towards said target object.

25. The method of claim 24, further comprising illuminating said target object.