Visual fiber placement inspection

Abstract

An apparatus and method are provided for performing, on-the-fly, real time inspection of a composite structure formed by an automated fiber placement machine, through comparison of a visual image of at least a portion of the composite structure to a virtual image of the composite structure. Proper formation of the structure, and/or anomalies within the structure, are determined by comparing the visual image to the virtual image. The automated fiber placement machine, and/or tooling upon which the fiber is placed, are manipulated, and a visual indicator are provided to facilitate inspection and/or repair of any detected anomalies during fabrication of the composite structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, forming a part of the specification, illustrate several aspects of the present invention and, which, together with the description, serve to explain the invention. In the drawings:

FIG. 1 is a combined schematic and flowchart illustration of an exemplary embodiment of a method and apparatus, according to the invention, which provides on-the-fly, real time inspection of a composite structure formed by an automated fiber placement machine, by comparing a visual image of at least a portion of the structure to a virtual image of the at least a portion of the structure;

FIGS. 2-4 are, respectively, a top plan view, a side elevation view, and a ply chart for an exemplary composite structure of the type which might be inspected using an apparatus and/or method according to the invention.

FIGS. 5A-5E are schematic illustrations of exemplary courses of fiber tows, of the type which might be inspected utilizing an apparatus and/or method according to the invention.

Claims

1. A method for inspecting a composite structure formed from one or more composite tows by an automated fiber placement machine, the method comprising, comparing a visual image of at least a portion of the composite structure to a virtual image of the at least a portion of the composite structure.

2. The method of claim 1, further comprising, determining proper formation of the structure, by comparing the visual image of at least a portion of the part to the virtual image of the part.

3. The method of claim 1, further comprising, determining improper formation of the structure, by comparing the visual image of at least a portion of the structure to the virtual image of the part.

4. The method of claim 3, further comprising manipulating the automated fiber placement machine to facilitate inspection and/or repair of the improper formation.

5. The method of claim 3, wherein, the method includes providing a visual indication of a detected imperfection.

6. The method of claim 3, further comprising, providing a location of the imperfection on the structure.

7. The method of claim 6, further comprising, providing a visible indication of the location of the imperfection.

8. The method of claim 7, wherein, the visible indication is provided by an automatically directed laser pointer.

9. The method of claim 8, further comprising, moving the structure and/or at least a portion of the automated fiber placement machine to a position whereat the imperfection may by indicated by the laser pointer.

10. The method of claim 1, wherein the structure is formed from one or more plies having multiple tows, and the method further includes comparing a visual image of the tows in a given ply to a virtual image of the tows in a given ply.

11. The method of claim 10, wherein the visual image of the tows is a two dimensional profile plot of an outer surface of the tows.

12. The method of claim 1, wherein the automated fiber placement machine includes a fiber placement head, and the visual image is taken by a vision capture element operatively connected to the fiber placement head.

13. The method of claim 12, wherein the vision capture element is mounted on the fiber placement head.

14. The method of claim 12, wherein the fiber placement head includes a feed roller for feeding out one or more tows of material, and the method further comprises utilizing a rotation sensor operatively connected to the feed roller for synchronization of the visual image with the virtual image.

15. The method of claim 1, wherein one or both of the virtual image and the visual image are located along a U-axis extending through at least a portion of at least one course of material laid down by the automated fiber placement head during formation of the composite structure.

16. A computer-readable medium having computer executable instructions for performing the method of claim 1.

17. The computer-readable medium of claim 16, having further computer executable instructions for performing the step of determining proper formation of the structure, by comparing the visual image of at least a portion of the part to the virtual image of the part.

18. The computer-readable medium of claim 16, having further computer executable instructions for performing the step of determining improper formation of the structure, by comparing the visual image of at least a portion of the structure to the virtual image of the part.

19. The computer-readable medium of claim 18, having further computer executable instructions for performing the step of manipulating the automated fiber placement machine to facilitate inspection and/or repair of the improper formation.

20. The computer-readable medium of claim 16, having further computer executable instructions for performing the step of providing a location of the imperfection on the structure.

21. The computer-readable medium of claim 16, having further computer executable instructions for performing the step of providing a visible indication of the location of the imperfection.

22. A method for inspecting a composite structure, formed by an automated fiber placement machine from a plurality of fiber tows laid down by the automated fiber placement machine, the method comprising: constructing a virtual image of the structure, prior to forming the composite structure, defining a proper placement and configuration of each of the plurality of fiber tows within the composite structure;taking a visual image of the appearance of the tows forming at least a portion of the composite structure, in real time, as the composite structure is formed by the automated fiber placement machine; and thencomparing the visual image of the appearance of the tows in the at least a portion of the structure to the proper configuration and placement of the fiber tows as defined in the virtual image of the at least a portion of the composite structure.

23. The computer-readable medium of claim 22, having further computer executable instructions for performing the step of determining proper formation of the structure, by comparing the visual image of at least a portion of the part to the virtual image of the part.

24. The computer-readable medium of claim 22, having further computer executable instructions for performing the step of determining improper formation of the structure, by comparing the visual image of at least a portion of the structure to the virtual image of the part.

25. The computer-readable medium of claim 24, having further computer executable instructions for performing the step of manipulating the automated fiber placement machine to facilitate inspection and/or repair of the improper formation.

26. The computer-readable medium of claim 22, having further computer executable instructions for performing the step of providing a location of the imperfection on the structure.

27. The computer-readable medium of claim 22, having further computer executable instructions for performing the step of providing a visible indication of the location of the imperfection.

28. An apparatus for inspecting a composite structure formed from one or more composite tows by an automated fiber placement machine, the apparatus comprising, a composite comparison device (CCD), for comparing a visual image of at least a portion of the composite structure to a virtual image of the at least a portion of the composite structure.

29. The apparatus of claim 28, further comprising, a vision capture element, for taking a visual image of a ply profile in the at least a portion of the composite structure, in real-time, on-the-fly, as the ply is laid down by the automated fiber placement machine, and for providing the visual image to the CCD.

30. The apparatus of claim 28, further comprising: a composite programming system (CPS); anda machine control system (MCS);the CPS being configured for determining where all tows will be dropped and/or added to meet boundary and interband gap/overlap criteria set out by a designer of a composite structure, and providing CPS outputs including, a numerical control (NC) file and a theoretical ply profile;the NC file representing the path of a compaction roller in a fiber placement head of a fiber placement machine, and being provided as an input to the MCS;the theoretical ply profile representing each band of tows as it is laid, as a course, onto the surface of a tool, or the surface of a previously laid ply of the composite structure, and being provided as an input to the CCD;the MCS being configured for utilizing the NC file for driving the fiber placement machine and/or a tool in such a manner as to lay a tow, or band of tows, at a desired location on the tool;the MCS also being configured for providing synchronization commands to the CCD, so that both the MCS and the CCD can be calibrated to the same position along each course;the CCD being configured for capturing a visual image of the actual lay-up surface of the tows, as they are laid down by the placement head, and for comparing the actual ply profile as captured in the visual image to the theoretical ply profile.

31. The apparatus of claim 28, further comprising, a vision capture element, for taking a visual image of a ply profile in the at least a portion of the composite structure, in real-time, on-the-fly, as the ply is laid down by the automated fiber placement machine, and for providing the visual image to the CCD.

32. The apparatus of claim 30, wherein, the CCD is further configured for producing a transferable file record of results of the CCD comparison of the visual image to the theoretical ply profile.

33. The apparatus of claim 32, wherein, the CCD is further configured for detecting and recording any discrepancies and/or anomalies between the actual and theoretical ply profiles.

34. The apparatus of claim 33, wherein, the MCS is further configured for receiving the results of the CCD comparison, and providing an output for guiding an operator of the fiber placement machine to each discrepancy and/or anomaly location, to thereby facilitate evaluation, repair, or any other action that may be deemed appropriate.

35. The apparatus of claim 34, further including, a pointing device, producing an output in the form of a visible light beam directed by the MCS for indicating the location of one or more discrepancy and/or anomaly in the composite structure.

36. The apparatus of claim 35, wherein, the visible light beam is a laser beam.