Apparatus and method for performing non-destructive inspections of large area aircraft structures

• US 6,220,099 B1
• Filed: 01/15/1999
• Issued: 04/24/2001
• Est. Priority Date: 02/17/1998
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: CE Nuclear Power, LLC (Brookfield Asset Management Incorporated)
• Inventors: Descant, Gene Joseph, Craig, Steven M., Marti, David Kenneth
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US09/231,668
• Time in Patent Office: 830 Days
• Field of Search: 736/18, 736/19, 736/20, 736/21, 736/22, 736/27, 736/29, 736/33, 736/34
• US Class Current: 73/633
• CPC Class Codes: G01N 2291/0231 Composite or layered materials
• CPC Class Codes: G01N 2291/2638 Complex surfaces
• CPC Class Codes: G01N 2291/2694 Wings or other aircraft parts
• CPC Class Codes: G01N 27/902 by moving the sensors
• CPC Class Codes: G01N 29/0609 Display arrangements, e.g. colour displays indicating or recording in connection with measuring in general G01D
• CPC Class Codes: G01N 29/0645 Display representation or displayed parameters, e.g. A-, B- or C-Scan
• CPC Class Codes: G01N 29/069 Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique
• CPC Class Codes: G01N 29/22 Details , e.g. general constructional or apparatus details
• CPC Class Codes: G01N 29/225 Supports, positioning or alignment in moving situation
• CPC Class Codes: G01N 29/226 Handheld or portable devices
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material
• CPC Class Codes: G01N 29/4463 Signal correction, e.g. distance amplitude correction [DAC], distance gain size [DGS], noise filtering

Abstract

A surface scanner for conducting non-destructive inspection of complex surface structures and configurations. The scanner includes two flexible tracks, each fitted with a motor driven tractor assembly. A rigid beam track spans the two flexible tracks. The rigid beam track is coupled to each flexible track tractor assembly by articulating joints that permit movement at the joints along at least three independent axes. The rigid beam supports a third motorized tractor. This third tractor supports a compliant thruster assembly that deploys gimbaled mechanical impedance, ultrasonic and eddy current inspection probes. The movement of the scanner is controlled by a scan control system that includes both hardware and software for controlling the movement of the scanner over the surface to be inspected. The software also includes a teach mode that permits an operator to preprogram the scan pattern for the surface to be inspected using a global coordinate system, referencing points on the surface and the data display using an identical coordinate system. The scanner also includes a data acquisition and analysis system that control scanner functions and operations.

Claims

1. A surface scanner comprising:

a first flexible track assembly supporting a first motorized tractor assembly;

a second flexible track assembly supporting a second motorized tractor assembly;

a third track assembly supported by the first track assembly and the second flexible track assembly;

a third motorized tractor assembly supported by the third track assembly;

a thruster assembly supported by the third motorized tractor assembly;

at least one inspection probe supported by the thruster assembly;

scan control means for moving said at least one inspection probe over a surface to be inspected; and

data acquisition and analysis means for acquiring data from said inspection probe related to a scan of at least a portion of said surface, and analyzing said data for defects in said surface.

2. The surface scanner as defined in claim 1, wherein the first flexible track assembly and the second flexible track assembly include a plurality of interconnecting track plates.

3. The surface scanner as defined in claim 2, wherein the track plates are flexible members, said track plates do not plastically deform upon bending and twisting.

4. The surface scanner as defined in claim 3, wherein the interconnecting track plates are fabricated of spring steel.

5. The surface scanner as defined in claim 3, wherein the track plates are adjusted to mate with complex surface configurations.

6. The surface scanner as defined in claim 5, wherein the track plates are adjusted to mate with aircraft surfaces.

7. The surface scanner as defined in claim 1, wherein the first flexible track assembly and the second flexible track assembly support a plurality of vacuum cup assemblies coupled to a vacuum source.

8. The surface scanner as defined in claim 7, wherein the scanner includes a warning for alerting an operator of a loss of vacuum pressure.

9. The surface scanner as defined in claim 8, wherein each vacuum cup forming the plurality of vacuum cup assemblies includes a mounting hinge for adjusting the angular position of the vacuum cup assembly.

10. The surface scanner as defined in claim 1, wherein the first flexible track assembly and the second flexible track assembly support end of travel stops at each end thereof.

11. The surface scanner as defined in claim 1, wherein the first flexible track assembly and the second flexible track assembly each supports gear racks.

12. The surface scanner as defined in claim 11, wherein each gear rack receives a mating gear supported by the respective tractor assembly.

13. The surface scanner as defined in claim 12, wherein the mating gear is a pinion gear.

14. The surface scanner as defined in claim 13, wherein the pinion gear is motor driven.

15. The surface scanner as defined in claim 1, wherein the first tractor assembly and the second tractor assembly support a plurality of guide rollers for engaging, respectively, the first flexible track assembly and the second flexible track assembly.

16. The surface scanner as defined in claim 1, wherein the first tractor assembly and the second tractor assembly support at least one clamping handle for respectively coupling the first tractor assembly and the second tractor assembly to the first flexible track assembly and the second flexible track assembly.

17. The surface scanner as defined in claim 1, wherein the first tractor assembly and the second tractor assembly each supports an optical encoder.

18. The surface scanner as defined in claim 1, wherein the second tractor assembly includes a position adjustment mechanism for permitting movement along three axes of freedom relative to the third track assembly.

19. The surface scanner as defined in claim 1, wherein the third track assembly includes one track plate coupled to a rigid strut.

20. The surface scanner as defined in claim 19, wherein the third track assembly is fabricated with a spring steel track plate and aluminum strut.

21. The surface scanner as defined in claim 1, wherein the third track assembly supports end of travel stops at each end thereof.

22. The surface scanner as defined in claim 1, wherein the third track assembly supports a gear rack.

23. The surface scanner as defined in claim 22, wherein the gear rack receives a mating gear supported by the third tractor assembly.

24. The surface scanner as defined in claim 23, wherein the mating gear is a pinion gear.

25. The surface scanner as defined in claim 24, wherein the pinion gear is motor driven.

26. The surface scanner as defined in claim 1, wherein the third tractor assembly supports a plurality of guide rollers for engaging the third track assembly.

27. The surface scanner as defined in claim 1, wherein the third tractor assembly supports at least one clamping handle for coupling the third tractor assembly to the third track assembly.

28. The surface scanner as defined in claim 1, wherein the third tractor assembly supports an optical encoder.

29. The surface scanner as defined in claim 1, wherein the surface scanner is lightweight.

30. The surface scanner as defined in claim 1, wherein articulating joints couple the third track assembly to the first track assembly and the second track assembly.

31. The surface scanner as defined in claim 30, wherein the joints permit non-parallelism and twist of the first track assembly and second track assembly relative to one another.

32. The surface scanner as defined in claim 30, wherein the joints are quick connect and disconnect couplers.

33. The surface scanner as defined in claim 1, wherein the third track assembly supports a master mounting bracket for permitting movement along multiple axes of freedom.

34. The surface scanner as defined in claim 33, wherein the master mounting bracket includes an angle dial plate.

35. The surface scanner as defined in claim 34, wherein the master mounting bracket includes an indicator for marking the angular position of the angle dial plate.

36. The surface scanner as defined in claim 35, wherein the master mounting bracket includes a pivot mechanism for permitting a relative change in position of the third track assembly and the first track assembly.

37. The surface scanner as defined in claim 36, wherein the pivot mechanism includes an upper pivot block and a lower pivot block.

38. The surface scanner as defined in claim 1, wherein the scanner includes vacuum coupled fixturing for offsetting the first track assembly and the second track assembly from the edges of the surface to be inspected.

39. The surface scanner as defined in claim 1, wherein the third track assembly has a liner stroke of 6 feet.

40. The surface scanner as defined in claim 1, wherein the third tractor assembly supports a BNC connector array.

41. The surface scanner as defined in claim 1, wherein the third tractor assembly supports said thruster assembly for moving the scanner over the surface to be inspected.

42. The surface scanner as defined in claim 41, wherein the thruster assembly is supported by either the top or bottom surface of the third track assembly.

43. The surface scanner as defined in claim 42, wherein the thruster assembly includes a slide block for facilitating movement of the thruster assembly.

44. The surface scanner as defined in claim 1, wherein the third tractor assembly supports nondestructive inspection probes.

45. The surface scanner as defined in claim 44, wherein the third tractor assembly includes a gimbal for supporting one or more nondestructive inspection (NDI) probes.

46. The surface scanner as defined in claim 45, wherein the NDI probes include mechanical impedance, ultrasonic or eddy current NDI probes.

47. The surface scanner as defined in claim 45, wherein the inspection probes include a single transducer probe.

48. The surface scanner as defined in claim 45, wherein the inspection probes include an eddy current probe sled assembly.

49. The surface scanner as defined in claim 45, wherein the gimbal positively loads the inspection probes, keeping them in contact with the surface to be inspected.

50. The surface scanner as defined in claim 49, wherein the gimbal supports a gas spring for positively loading the inspection probes.

51. The surface scanner as defined in claim 50, wherein an interface block couples the gas spring to the gimbal.

52. The surface scanner as defined in claim 1, wherein the scanner further includes a plurality of inspection probes that are NDI probes and said scanner includes a couplant delivery system for supplying couplant fluid to the NDI probes.

53. The surface scanner as defined in claim 52, wherein the probes are ultrasonic probes and said couplant delivery system supplies couplant fluid to the ultrasonic NDI probes.

54. The surface scanner as defined in claim 52, wherein the couplant delivery system includes a delivery pump for circulating the couplant fluid, a supply tank for retaining the couplant fluid, and tubing interconnecting the pump, the supply tank and the NDI probes.

55. The surface scanner as defined in claim 54, wherein the couplant deliver system includes a filter for removing particulates from the couplant fluid.

56. The surface scanner as defined in claim 54, wherein the couplant delivery system further includes couplant retrieval gutters.

57. The surface scanner as defined in claim 52, wherein the data acquisition and analysis means includes a system for analyzing and storing the data acquired by the NDI probes.

58. The surface scanner as defined in claim 57, wherein the data acquisition and analysis system includes both hardware and software subsystems.

59. The surface scanner as defined in claim 58, wherein the data acquisition and analysis hardware subsystem includes a host computer.

60. The surface scanner as defined in claim 59, wherein the computer is portable.

61. The surface scanner as defined in claim 59, wherein the computer includes an Intel 486 DX2/66 MHz microprocessor.

62. The surface scanner as defined in claim 59, wherein the computer includes 64 Mb of RAM.

63. The surface scanner as defined in claim 59, wherein the data acquisition and analysis system includes an uninterruptible power supply.

64. The surface scanner as defined in claim 59, wherein the computer includes an outer chassis.

65. The surface scanner as defined in claim 64, wherein the chassis houses a keyboard.

66. The surface scanner as defined in claim 65, wherein the chassis supports a visual display for displaying the acquired and processed data from said data acquisition and analysis means.

67. The surface scanner as defined in claim 66, wherein the visual display is a VGA monitor.

68. The surface scanner as defined in claim 67, wherein the VGA monitor is a color monitor.

69. The surface scanner as defined in claim 64, wherein the chassis supports a pointing device.

70. The surface scanner as defined in claim 64, wherein the chassis includes ports for connecting to external devices.

71. The surface scanner as defined in claim 64, wherein the chassis includes ports for connecting to external devices.

72. The surface scanner as defined in claim 64, wherein the chassis supports a connection for a joystick.

73. The surface scanner as defined in claim 64, wherein the chassis supports a data storage means for storing said data.

74. The surface scanner as defined in claim 73, wherein the data storage means is a floppy disk drive.

75. The surface scanner as defined in claim 73, wherein the data storage means is an internal storage device.

76. The surface scanner as defined in claim 73, wherein the data storage means is a combination of an external storage device and an internal storage device.

77. The surface scanner as defined in claim 6, wherein the internal and external storage devices includes a 1.44 Mb 3.5 floppy disk drive in combination with a 500 Mb internal hard drive, and an external 1 Gb read/write optical drive.

78. The surface scanner as defined in claim 57, wherein the data acquisition and analysis means further cooperates with the scan control means, including a scan control system, for controlling the movement of the scanner.

79. The surface scanner as defined in claim 78, wherein the scan control system includes a scan control board.

80. The surface scanner as defined in claim 79, wherein the scan control board is a multi-axis controller, controlling movement of the first tractor assembly, the second tractor assembly, the third tractor assembly and the thruster assembly.

81. The surface scanner as defined in claim 80, wherein the scan control system includes software for controlling the function of the scan control board.

82. The surface scanner as defined in claim 81, wherein a scan pattern of the scanner is preprogrammed.

83. The surface scanner as defined in claim 82, wherein the scan pattern is programmed using a teach-and-learn technique for inputting data points that define the overall scan area and shape.

84. The surface scanner as defined in claim 82, wherein the scan pattern is programmed using a global coordinate system which permits referencing data points using identical coordinate systems laid-out on the actual surface to be inspected and the display of the scanned image.

85. The surface scanner as defined in claim 57, wherein the data acquisition and analysis means further includes an ultrasonic board for processing ultrasonic data.

86. The surface scanner as defined in claim 57, wherein the data acquisition and analysis means further includes a hardware subsystem having an eddy current board for processing eddy current data.

87. The surface scanner as defined in claim 57, wherein the data acquisition and analysis means further includes a software subsystem having software files for controlling scanner system operations.

88. The surface scanner as defined in claim 87, wherein the software subsystem includes software for performing ultrasonic data processing and analysis.

89. The surface scanner as defined in claim 87, wherein the software subsystem includes software for performing eddy current data processing and analysis.

90. The surface scanner as defined in claim 87, wherein the software subsystem includes software for performing mechanical impedance data processing and analysis.

91. A surface scanner comprising:

a first flexible track assembly supporting a first tractor assembly;

a second flexible track assembly supporting a second tractor assembly;

a third track assembly, one end thereof being supported by the first flexible track assembly and the opposite end being supported by the second flexible track assembly;

a third tractor assembly supported by the third track assembly;

a thruster assembly supported by the third tractor assembly;

one or more NDI probes supported by the thruster assembly for acquiring data concerning a surface to be inspected;

a scan control system for moving the NDI probes over the surface to be inspected; and

a data acquisition and analysis system for processing and analyzing the data acquired by the NDI probe.

92. The surface scanner as defined in claim 91, wherein the scanner includes a couplant delivery system for delivering couplant fluid to the NDI probes.

93. The surface scanner as defined in claim 91, wherein the NDI probes include ultrasonic, eddy current and mechanical impedance data probes.

94. The surface scanner as defined in claim 91, wherein the data acquisition and analysis system includes hardware and software subsystems for controlling scanner functions.

95. The surface scanner as defined in claim 91, wherein in the scan control system includes a global coordinate system for referencing data points on the surface under inspection and displaying an image correlated with said data points.

96. A method for installing a surface scanner comprising:

coupling a first track assembly onto a surface to be inspected;

drawing a vacuum pressure through vacuum cups supported by the first track assembly, creating a suction force adhering the vacuum cups to the surface;

coupling a first tractor assembly to the first track assembly;

coupling a second track assembly onto a surface to be inspected such that first track assembly is offset from the second track assembly;

drawing a vacuum pressure through vacuum cups supported by the second track assembly, creating a suction force adhering the vacuum cups to the surface;

coupling a second tractor assembly to the second track assembly;

coupling a third track assembly to the first track assembly and the second track assembly such that the third track assembly spans the gap between the first track assembly and the second track assembly;

coupling a third tractor assembly to the third track assembly;

coupling a thruster to the third tractor assembly, wherein the thruster supports NDI probes; and

controlling movement of said NDI probes over at least a portion of a surface to be scanned to acquire data from said NDI probes related to said scan.

97. The method of installing a surface scanner as defined in claim 96, wherein the step of controlling movement further includes step of an external data acquisition and analysis for controlling scanner functions.

98. The method of installing a surface scanner as defined in claim 97, wherein the step of data acquisition and analysis includes software for defining a global coordinate system for referencing a point on the surface inspected to an identical point on a corresponding scanned image.