Coordinating end effector and vision controls

• US 10,203,683 B2
• Filed: 07/16/2013
• Issued: 02/12/2019
• Est. Priority Date: 07/16/2013
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Pfeiffer, Michael, Spiczka, Kevin
• Primary Examiner(s): Shechtman, Sean
• Application Number:
  US13/942,820
• Publication Number:
  US 20150025674A1
• Time in Patent Office: 2,037 Days
• Field of Search: None
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 19/4086 Coordinate conversions; Other special calculations
• CPC Class Codes: G05B 2219/37009 Calibration of vision system, camera, adapt light level

Abstract

An apparatus and associated methodology providing a processor-controlled end effector that is selectively moveable according to end effector coordinates. A camera is positioned to detect objects according to camera coordinates that overlap the end effector coordinates. Logic executes computer instructions stored in memory to obtain a plurality of paired values of end effector coordinates and camera coordinates for each of a plurality of fiducial features, and to derive a transformation function from the plurality of paired values mapping the camera coordinates to the end effector coordinates.

Claims

1. An apparatus comprising:

a gage defining a fiducial feature in a reference plane;

an end effector configured to locate the fiducial feature with respect to end effector coordinates of the reference plane;

a camera configured to locate the fiducial feature with respect to camera coordinates of the reference plane that are different than the end effector coordinates of the reference plane; and

a processor executing computer logic stored in memory that is configured to move the end effector to pair the end effector coordinates and the camera coordinates for each of a plurality of fiducial features, and to perform a minimum mean square error estimation for the plurality of paired values to derive a transformation function mapping the camera coordinates to the end effector coordinates.

2. The apparatus of claim 1 wherein the gage is supported by an actuator configured to selectively move the gage in directions orthogonal to the reference plane.

3. The apparatus of claim 1 wherein the computer logic operably activates a switch to selectively ground the end effector.

4. The apparatus of claim 3 wherein the computer logic operably detects a surface of the gage in response to receiving an electrical continuity signal from the end effector.

5. The apparatus of claim 1 wherein the computer logic operably locates a plurality of fiducial features of the gage with the end effector and with the camera.

6. The apparatus of claim 1 wherein the computer logic stores the transformation function in the memory.

7. The apparatus of claim 1 wherein the logic operably identifies a target location with respect to target camera coordinates of the reference plane, inputs the target camera coordinates to the transformation function to calculate mapped end effector coordinates of the reference plane, and moves the end effector to the target location by commanding the end effector to move to the mapped end effector coordinates.

8. The apparatus of claim 1 wherein at least one of the plurality of fiducial features is a circular opening in a gage, and wherein the logic operably calculates coordinates of a center of the circular opening.

9. The apparatus of claim 8 wherein the computer logic operably detects a plurality of points on the surface defining the circular opening, and from the plurality of points calculates the center of the opening.

10. The apparatus of claim 8 comprising a gage defining the plurality of fiducial features that is stationary in directions parallel to the reference plane.

11. A method comprising:

obtaining an apparatus having a gage defining a fiducial feature in a reference plane, a selectively moveable end effector configured to locate the fiducial feature with respect to end effector coordinates of the reference plane, and also having a camera configured to locate the fiducial feature with respect to camera coordinates of the reference plane that are different than the end effector coordinates of the reference plane; and

operating a processor to execute computer instructions stored in memory that are configured to move the end effector to pair the end effector coordinates and the camera coordinates for each of a plurality of fiducial features, and further configured to perform a minimum mean square error estimation for the plurality of paired values to derive a transformation function mapping the camera coordinates to the end effector coordinates.

12. The method of claim 11 further comprising moving the gage orthogonally to the reference plane.

13. The method of claim 11 further comprising electrically grounding the end effector.

14. The method of claim 13 further comprising receiving an electrical continuity signal when the end effector detects a surface of the gage.

15. The method of claim 11 further comprising locating a plurality of fiducial features of the gage with the end effector and with the camera.

16. The method of claim 11 wherein the fiducial feature is a circular opening, and further comprising detecting a plurality of points on the surface of the gage defining the circular opening and calculating the center of the circular opening from the detected points.

17. The method of claim 11 further comprising storing the transformation function in the memory.

18. The method of claim 11 further comprising identifying a target location via target camera coordinates, inputting the target coordinates to the transformation function to calculate the mapped end effector coordinates, and moving the end effector to the mapped end effector coordinates.