Micropositioning system

• US 6,472,676 B1
• Filed: 11/20/2000
• Issued: 10/29/2002
• Est. Priority Date: 10/09/1999
• Status: Expired due to Fees

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Douglas, Anthony J, Beggs, Kevin W, Jarvis, Paul E
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): Ho, Allen C
• Application Number:
  US09/700,880
• Time in Patent Office: 708 Days
• Field of Search: 250/559.29, 250/559.3, 250/559.33, 250/208.1, 356/614, 356/615
• US Class Current: 250/559.33
• 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

Abstract

The present invention provides an apparatus and a method for accurately positioning tools for use in manufacturing or inspection operations whilst reducing the need for costly tooling such as jigs.

The method for accurately positioning tools comprises at least the steps of

projecting an image onto a surface, detecting the projected image, processing the projected image, calculating at least two dimensional co-ordinates of the projected image relative to a tool, and moving the tool so that it is positioned in a pre-defined spacial relationship with respect to the projected image.

The micropositioning system comprises

a radiation source for projecting an image onto a surface, a radiation detector for detecting the projected image, tool conveyancing means for carrying a tool, processor means for calculating at least two dimensional co-ordinates of the projected image detected by the radiation detector relative to the tool, and control means for controlling the tool conveyancing means so as to position the tool in a pre-defined spacial relationship with the projected image in response to a signal from the processor means.

Claims

1. A micropositioning system for carrying out manufacturing or inspection operations on an article, said system comprising:

a radiation source for projecting an image onto a surface of said article, the image being part of a manufacturing template obtained directly from a CAD model of the article and the image representing a predetermined position on the surface of the article where said manufacturing or inspection operations are to be undertaken;

a radiation detector for detecting the projected image;

tool conveyancing means for carrying a tool adapted to perform said manufacturing or inspection operations;

processor means for calculating at least two dimensional co-ordinates of the projected image detected by the radiation detector relative to the tool and

control means for controlling the tool conveyancing means so as to position the tool in a pre-defined spatial relationship with the projected image in response to a signal from the processor means.

2. A micropositioning system as claimed in claim 1 wherein the radiation detector comprises a camera and an image processing system.

3. A micropositioning system as claimed in claim 2 wherein the camera comprises an array of solid state charge coupled devices.

4. A micropositioning system as claimed in claim 2 wherein the image processing system comprises a frame grabber for digitising the image and a computer adapted for processing the image.

5. A micropositioning system as claimed in claim 4 wherein the image is processed by the computer to identify features such as areas of the same intensity or changes in intensity.

6. A micropositioning system as claimed in claim 5 wherein the image is processed by the computer to locate the centre of the image.

7. A micropositioning system as claimed in claim 1 wherein the tool conveyancing means comprises a tool holding device mounted on a moveable stage.

8. A micropositioning system as claimed in claim 7 wherein the moveable stage is mounted on a platform.

9. A micropositioning system as claimed in claim 7 the tool holding device is adapted to move relative to the moveable stage.

10. A micropositioning system as claimed in claim 1 wherein the micropositioning system comprises normalisation means for checking that the tool is substantially normal to the surface prior to a manufacturing operation being carried out.

11. A micropositioning system as claimed in claim 1 wherein the processor means uses data obtained from an image processing system to determine the location of the image with respect to the position of the tool.

12. A micropositioning system as claimed in claim wherein the control means comprises a motion controller for controlling the movement of the tool conveyancing means.

13. A micropositioning system as claimed in claim 12 wherein the control means further comprises a servo motor.

14. A micropositioning system comprising:

a radiation source for projecting an image onto a surface of an article, the image being part of a manufacturing template and the image representing a predetermined position on the surface of the article where a manufacturing or inspection operation is to be undertaken;

a radiation detector for detecting the projected image;

tool conveyancing means for carrying a tool adapted to perform manufacturing or inspection operations;

processor means for calculating at least two dimensional co-ordinates of the projected image detected by the radiation detector relative to the tool and

control means for controlling the tool conveyancing means so as to position the tool in a pre-defined spatial relationship with the projected image in response to a signal from the processor means,

wherein the tool conveyancing means comprises a tool holding device mounted on a moveable stage, and the moveable stage is mounted on a platform,

wherein the platform comprises attachment means for allowing the platform to be releasably attached to the surface.

15. A micropositioning system comprising:

a radiation source for projecting an image onto a surface of an article, the image being part of a manufacturing template and the image representing a predetermined position on the surface of the article where a manufacturing or inspection operation is to be undertaken;

a radiation detector for detecting the projected image;

tool conveyancing means for carrying a tool adapted to perform manufacturing or inspection operations;

processor means for calculating at least two dimensional co-ordinates of the projected image detected by the radiation detector relative to the tool and control means for controlling the tool conveyancing means so as to position the tool in a pre-defined spatial relationship with the projected image in response to a signal from the processor means,

wherein the tool conveyancing means comprises a tool holding device mounted on a moveable stage, and the moveable stage is mounted on a platform,

wherein the platform comprises one or more adjustable feet for adjusting the distance between the surface and the platform.

16. A micropositioning system comprising:

a radiation source for projecting an image onto a surface of an article, the image being part of a manufacturing template and the image representing a predetermined position on the surface of the article where a manufacturing or inspection operation is to be undertaken;

a radiation detector for detecting the projected image;

tool conveyancing means for carrying a tool adapted to perform manufacturing or inspection operations;

processor means for calculating at least two dimensional co-ordinates of the projected image detected by the radiation detector relative to the tool and

control means for controlling the tool conveyancing means so as to position the tool in a pre-defined spatial relationship with the projected image in response to a signal from the processor means,

wherein the micropositioning system comprises normalisation means for checking that the tool is substantially normal to the surface prior to a manufacturing operation being carried out;

wherein the normalisation means automatically controls at least one adjustable foot.

17. A micropositioning system comprising:

a radiation source for projecting an image onto a surface of an article, the image being part of a manufacturing template and the image representing a predetermined position on the surface of the article where a manufacturing or inspection operation is to be undertaken;

a radiation detector for detecting the projected image;

tool conveyancing means for carrying a tool adapted to perform manufacturing or inspection operations;

processor means for calculating at least two dimensional co-ordinates of the projected image detected by the radiation detector relative to the tool and

control means for controlling the tool conveyancing means so as to position the tool in a pre-defined spatial relationship with the projected image in response to a signal from the processor means,

wherein the tool conveyancing means comprises an extendable arm for holding a tool.

18. A method for accurately positioning tools comprising at least the steps of:

projecting an image onto a surface of an article, the image being part of a manufacturing template obtained directly from a CAD model of the article and the image representing a predetermined position on the surface of the article where a manufacturing or inspection operation is to be undertaken;

detecting the projected image

processing the projected image

calculating at least two dimensional co-ordinates of the projected image relative to a tool adapted to perform said manufacturing or inspection operation; and

moving the tool so that it is positioned in a pre-defined spatial relationship with respect to the projected image.

19. A method as claimed in claim 18 wherein the precise location of the article relative to the radiation source is determined by known positioning techniques prior to projecting the image onto the surface of the article.

20. A method as claimed in, claim 18 wherein the tool is normalised prior to use so that in use its line of action is normal to the surface.

21. A method as claimed in claim 18 wherein the centre of the projected image is located during the processing of the projected image.

22. A method as claimed in claim 21 wherein two dimensional co-ordinates of the centre of the projected image relative to the tool are calculated by a processor.

23. A method as claimed in claim 22 wherein the processor sends a signal to a motion controller to cause the tool to be moved so that it is located at the same two dimensional co-ordinates as the centre of the projected image.

24. A method as claimed in claim 23, wherein the motion controller actuates a servo motor for moving the tool.