Method, apparatus and computer program product for determining shim shape

• US 6,618,505 B2
• Filed: 03/06/2001
• Issued: 09/09/2003
• Est. Priority Date: 03/09/2000
• Status: Expired due to Term

• Current Assignee: Spirit Aerosystems Incorporated (Spirit Aerosystems Holdings Incorporated)
• Original Assignee: The Boeing Co.
• Inventors: Lane, Ronald G., Cork, Glen P.
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): CARTER, AARON W
• Application Number:
  US09/800,026
• Publication Number:
  US 20010046323A1
• Time in Patent Office: 917 Days
• Field of Search: 382/203, 382/106, 382/108, 382/154, 382/204, 382/201, 382/100, 382/141, 382/152, 356/625-640, 250/559-9-5, 73/18.1, 738/658, 333/02, 700/160, 700/163, 700/182, 702/155, 702/156, 702/167, 702/1
• US Class Current: 382/190
• CPC Class Codes: B64F 5/00 Designing, manufacturing, assembling, cleaning, maintaining or repairing aircraft, not otherwise provided for; Handling, transporting, testing or inspecting aircraft components, not otherwise provided for
• CPC Class Codes: G05B 2219/35062 Derive mating, complementary, mirror part from computer model data

Abstract

A method and apparatus for determining a shape of a shim that can be inserted between a first body, such as a strut torque box, and a second body, such as a torque box skin, is disclosed. The strut torque box is marked with a plurality of retro-reflective markers at the desired locations needing to be shimmed. The positions of the markers are measured using digital photogrammetry equipment yielding a plurality of measured points. The measured points define a surface of the first body. The locations of the measured points are transformed relative to a surface of the second body to yield a profile of the shape of the shim. The present method and apparatus have the advantage of considerably reducing the labor required for manual shim measurement using gauges by allowing multiple shim points to be measured simultaneously and without the pre-assembly of the strut torque box and torque box skin.

Claims

1. An apparatus for determining a shape of a shim that can be inserted between a first body and a second body, the apparatus comprising:

a processing element for receiving a plurality of measured points that define a surface of the first body, said processing element also using an engineering surface and creating a vector passing through respective points of a group of the measured points and normal to the engineering surface, said processing element determining, for each point of the group, a distance between the engineering surface and a point that is local to the respective point in the group and is most outboard from the engineering surface, said processing element also constructing a plurality of new points with each new point associated with a respective point of the group and displaced the respective distance along the respective vector, said processing element further constructing a second surface of the second body from the plurality of new points so that the shape of the shim is defined between the plurality of measured points and the first surface.

2. The apparatus of claim 1, further comprising a plurality of targets each marking a position for the shim on the first body and a measurement device positioned to measure the plurality of targets and construct the plurality of measured points therefrom.

3. The apparatus of claim 2, wherein the measurement device is a photogrammetry device measuring the plurality of targets by capturing an optical image.

4. The apparatus of claim 3, wherein the targets are retro-reflective targets having a contrast detectable by the photogrammetry device.

5. The apparatus of claim 3, wherein the photogrammetry device includes a plurality of cameras.

6. The apparatus of claim 1, wherein the first body is a strut torque box and the second body is a skin.

7. The apparatus of claim 1, wherein the group of points and the plurality of new points each comprises at least three measured points.

8. The apparatus of claim 7, wherein said processing element repositions the new points until the measured points protrude less than a predetermined engineering tolerance into the second surface so that the shape of the shim is configured to form an interference fit between the first and second bodies.

9. An apparatus for determining a shape of a shim that can be inserted between a first body and a second body, the apparatus comprising:

a processing element for receiving a plurality of measured points that define a surface of the first body, said processing element also using an outboard mating surface of the second body and creating a vector passing through each point of a group of the measured points and normal to the outboard surface, said processing element determining, for each point of the group, a distance between the outboard mating surface and a point that is local to the respective point in the group and is most outboard from the outboard surface, said processing element also constructing a plurality of new points with each new point associated with a respective point of the group and displaced the respective distance along the respective vector and said processing element realigning the measured points until each point of the group of the measured points is coincident with each new point on the same vector so that the shape of the shim is defined between the plurality of measured points and the outboard mating surface.

10. The apparatus of claim 9, further comprising a plurality of targets each marking a position for the shim on the first body and a measurement device positioned to measure the plurality of targets and construct the plurality of measured points therefrom.

11. The apparatus of claim 10, wherein the measurement device is a photogrammetry device measuring the plurality of targets by capturing an optical image.

12. The apparatus of claim 11, wherein the targets are retro-reflective targets having a contrast detectable by the photogrammetry device.

13. The apparatus of claim 12, wherein the photogrammetry device includes a plurality of cameras.

14. The apparatus of claim 9, wherein the first body is a strut torque box and the second body is a skin.

15. The apparatus of claim 9, wherein said processing element repositions the new points until the measured points protrude less than a predetermined engineering tolerance into the outboard mating surface so that the shape of the shim is configured to form an interference fit between the first and second bodies.

16. The apparatus of claim 9, wherein the second body includes a tool locating detail and said processing element constructs the outboard mating surface from a position of the tool locating detail and a known displacement of the outboard mating surface with respect to the tool locating detail.

17. An apparatus for determining a shape of a shim that can be inserted between a first body and a second body, the apparatus comprising:

a processing element for receiving a plurality of measured points that define a surface of the first body, said processing element performing a maximum material best fit on the plurality of measured points to one side of a second surface of the second body so that the shape of the shim is defined between the plurality of measured points and the second surface which is an engineering surface.

18. The apparatus of claim 17, wherein said processing element offsets the second surface by a predetermined engineering tolerance so that the shape of the shim is configured to form an interference fit between the first and second bodies.

19. The apparatus of claim 17, further comprising a plurality of targets each marking a position for the shim on the first body and a measurement device positioned to measure the plurality of targets and construct the plurality of measured points therefrom.

20. The apparatus of claim 19, wherein the measurement device is a photogrammetry device measuring the plurality of targets by capturing an optical image.

21. The apparatus of claim 20, wherein the targets are retro-reflective targets having a contrast detectable by the photogrammetry device.

22. The apparatus of claim 20, wherein the photogrammetry device includes a plurality of cameras.

23. The apparatus of claim 17, wherein the first body is a strut torque box and the second body is a skin.

24. A method of determining a shape of a shim that can be inserted between a first body and a second body, the method comprising:

receiving a plurality of measured points that define a surface of the first body;

using an engineering surface and creating a vector passing through respective points of a group of the measured points and normal to the engineering surface;

determining, for each point of the group, a distance between the engineering surface and a point that is local to the respective point in the group and is most outboard from the engineering surface;

constructing a plurality of new points with each new point associated with a respective point of the group and displaced the respective distance along the respective vector; and

constructing a second surface of the second body from the plurality of new points so that the shape of the shim is defined between the plurality of measured points and the first surface.

25. The method of claim 24, further comprising the steps of marking a position for the shim on the first body, measuring positions of each of the plurality of targets and constructing the plurality of measured points from the positions of the plurality of targets.

26. The method of claim 25, wherein said measuring positions step includes capturing an optical image of the plurality of targets with a photogrammetry device.

27. The method of claim 24, further comprising the step of repositioning the new points until the measured points protrude less than a predetermined engineering tolerance into the second surface so that the shape of the shim is configured to form an interference fit between the first and second bodies.

31. The method of claim 24, further comprising the step of repositioning the new points until the measured points protrude less than a predetermined engineering tolerance into the outboard mating surface so that the shape of the shim is configured to form an interference fit between the first and second bodies.

28. A method of determining a shape of a shim that can be inserted between a first body and a second body, the method comprising:

receiving a plurality of measured points that define a surface of the first body;

using an outboard mating surface of the second body and creating a vector passing through respective points of a group of the measured points and normal to the outboard mating surface;

determining, for each point of the group, a distance between the outboard mating surface and a point that is local to the respective point in the group and is most outboard from the outboard mating surface;

constructing a plurality of new points with each new point associated with a respective point of the group and displaced the respective distance along the respective vector; and

realigning the measured points until each point of the group of the measured points is coincident with each new point on the same vector so that the shape of the shim is defined between the plurality of measured points and the outboard mating surface.

29. The method of claim 28, further comprising the steps of marking a position for the shim on the first body, measuring positions of each of the plurality of targets and constructing the plurality of measured points from the positions of the plurality of targets.

30. The method of claim 29, wherein said measuring positions step includes capturing an optical image of the plurality of targets with a photogrammetry device.

32. A computer program product for determining the shape of a shim that can be inserted between a first body and a second body comprising a computer-readable storage medium having computer-readable program code embodied in said medium, the computer-readable program code comprising:

a first computer-readable program code portion for receiving a plurality of measured points that define a surface of the first body;

a second computer-readable program code portion for using an engineering surface and creating a vector passing through respective points of a group of the measured points and normal to the engineering surface;

a third computer-readable program code portion for determining, for each point of the group, a distance between the engineering surface and a point that is local to the respective point in the group and is most outboard from the engineering surface;

a fourth computer-readable program code portion for constructing a plurality of new points with each new point associated with a respective point of the group and displaced the respective distance along the respective vector; and

a fifth computer-readable program code portion for constructing a second surface of the second body from the plurality of new points so that the shape of the shim is defined between the plurality of measured points and the first surface.

33. The computer program product of claim 32, further comprising a sixth computer-readable program code portion for repositioning the new points until the measured points protrude less than a predetermined engineering tolerance into the second surface so that the shape of the shim is configured to form an interference fit between the first and second bodies.

34. A computer program product for determining the shape of a shim that can be inserted between a first body and a second body, comprising a computer-readable storage medium having computer-readable program code embodied in said medium, the computer-readable program code comprising:

a first computer-readable program code portion for receiving a plurality of measured points that define a surface of the first body;

a second computer-readable program code portion for using an outboard mating surface of the second body and creating a vector passing through respective points of a group of the measured points and normal to the outboard mating surface;

a third computer-readable program code portion for determining, for each point of the group, a distance between the outboard mating surface and a point that is local to the respective point in the group and is most outboard from the outboard mating surface;

a fourth computer-readable program code portion for constructing a plurality of new points with each new point associated with a respective point of the group and displaced the respective distance along the respective vector; and

a fifth computer-readable program code portion for realigning the measured points until each point of the group of the measured points is coincident with each new point on the same vector so that the shape of the shim is defined between the plurality of measured points and the outboard mating surface.

35. The computer program product of claim 34, further comprising a computer-readable program code portion for repositioning the new points until the measured points protrude less than a predetermined engineering tolerance into the outboard mating surface so that the shape of the shim is configured to form an interference fit between the first and second bodies.

36. The computer program product of claim 35, further comprising a computer-readable program code portion for constructing the outboard mating surface from a position of a tool locating detail and a known displacement of the outboard mating surface with respect to the tool locating detail.

37. A method of determining a shape of a shim that can be inserted between a first body and a second body, the method comprising:

receiving a plurality of measured points that define a surface of the first body;

performing a maximum material best fit on the plurality of measured points to one side of a second surface of the second body so that the shape of the shim is defined between the plurality of measured points and the second surface which is an engineering surface; and

offsetting the second surface by a predetermined engineering tolerance so that the shape of the shim is configured to form an interference fit between the first and second bodies.

38. A computer program product for determining the shape of a shim that can be inserted between a first body and a second body, comprising a computer-readable storage medium having computer-readable program code embodied in said medium, the computer-readable program code comprising:

a first computer-readable program code portion for receiving a plurality of measured points that define a surface of the first body;

a second computer-readable program code portion for performing a maximum material best fit on the plurality of measured points to one side of a second surface of the second body so that the shape of the shim is defined between the plurality of measured points and the second surface which is an engineering surface; and

a third computer readable program code portion for offsetting the second surface by a predetermined engineering tolerance so that the shape of the shim is configured to form an interference fit between the first and second bodies.

39. An apparatus for determining a shape of a shim that can be inserted between a first body and a second body, the apparatus comprising:

a plurality of targets positioned at a plurality of shim points on the first body;

a measuring device positioned to measure the plurality of targets and create a plurality of measured points corresponding to the plurality of targets, said plurality of measured points defining a first surface of the first body; and

a processing element for receiving the plurality of measured points, said processing element using a second surface and transforming the locations of the measured points with respect to the second surface so that the shape of the shim is defined between the plurality of measured points and the second surface which is an engineering surface.

40. The apparatus of claim 39, wherein the processing element transforms the locations of the measured points by creating a vector passing through each point of a group of the measured points and normal to the second surface, said processing element determining, for each point of the group, a distance between the second surface and a point that is local to the respective point in the group and is most outboard from the second surface, said processing element also constructing a plurality of new points with each new point associated with a respective point of the group and displaced the respective distance along the respective vector and said processing element realigning the measured points until each point of the group of the measured points is coincident with each new point.

41. The apparatus of claim 39, wherein said processing element performs a maximum material best fit on the plurality of measured points to one side of the second surface of the second body.

42. The apparatus of claim 41, wherein said processing element offsets the second surface by a predetermined engineering tolerance so that the shape of the shim is configured to form an interference fit between the first and second bodies.