Light scanning system for measurement of orientation and physical features of a workpiece

• US 5,054,918 A
• Filed: 02/02/1990
• Issued: 10/08/1991
• Est. Priority Date: 02/02/1990
• Status: Expired due to Term

• Current Assignee: Snap-On Incorporated
• Original Assignee: FMC Corporation
• Inventors: Baird, Michael L., Rogers, Steven W., Downing, Elizabeth A., Christian, Donald J., Titsworth, Raymond
• Primary Examiner(s): Wallace, Linda J.
• Application Number:
  US07/473,754
• Time in Patent Office: 613 Days
• Field of Search: 356/152, 356/155, 33/203, 33/203.11, 33/288, 358/93, 358/107
• US Class Current: 356/139.09
• CPC Class Codes: G01B 11/2504 Calibration devices
• CPC Class Codes: G01B 2210/14 One or more cameras or other optical devices capable of acquiring a two-dimensional image
• CPC Class Codes: G01M 1/02 Details of balancing machines or devices

Abstract

A structured light scanning system observes, interprets and provides structural feature size, position and movement data in automotive service equipment applications where such feature characteristics must be determined either preliminary to or ultimately for measurement of quantities affecting automotive performance, such as tire/rim assembly balance, runout and alignment or brake surface planarity and smoothness.

Claims

1. A wheel rim/tire assembly parameter measurement apparatus for a dynamic wheel balancer having a spindle for mounting the wheel rim/tire assembly for rotation thereon, comprising

light beam projection means mounted on the wheel balancer providing a light beam directed along a path toward a wheel rim/tire assembly on the spindle,

optical means for converting said light beam to a beam contained in substantially a single plane,

light sensing means exposed to light reflected from the area on the rim/tire assembly impinged by the converted light beam for providing signals responsive thereto, and

means receiving said signals provided by said light sensing means for providing data relating to wheel rim/tire assembly feature locations, dimensions and physical configuration.

2. A wheel balancer as in claim 1 wherein said light beam projection means comprises means for mounting said light beam projection means to illuminate the periphery of the wheel rim/tire assembly with said light beam, whereby the wheel rim/tire assembly runout is measured.

3. A wheel balancer as in claim 1 wherein the wheel rim has an inner rim and an outer rim and wherein said light beam projection means comprises means for mounting said light beam projection means to illuminate the inner and outer rims with said light beam whereby inner and outer rim separation is measured.

4. A wheel balancer as in claim 3 wherein said light beam projection means comprises a beam splitter for splitting said light beam, and reflector means, each of said beam splitter and said reflector means functioning to direct a portion of said split light beam toward one of the inner and outer rims, respectively.

5. A wheel balancer as in claim 1 wherein the wheel rim has an inner rim and an outer rim and wherein said light beam projection means comprises means for mounting said light beam projection means to illuminate the inner and outer rims and the periphery of the wheel rim/tire assembly with said light beam whereby rim edge and tire valve locations, inner and outer rim separation, and wheel rim/tire assembly runout are measured.

6. A wheel balancer as in claim 5 wherein said light sensing means comprises first, second and third light sensors exposed to said inner rim, wheel rim/tire assembly periphery and outer rim respectively, means for digitizing said light sensing means signals, and a digital signal processing for providing said data relating to wheel rim/tire assembly location, dimensions and physical configuration.

7. A wheel balancer as in claim 1 wherein said light beam projection means comprises a laser light source.

8. A wheel balancer as in claim 1 wherein said light beam projection means comprises a white light source, and wherein said optical means comprises a collimator interposed in the path of said light beam from said white light source, and a cylindrical lens interposed in the path of said light beam from said collimator.

9. A wheel balancer as in claim 1 wherein said light sensing means comprises a band pass filter receiving the reflected light and passing filtered reflected light, a lens exposed to and operating to focus the filtered reflected light, and a charge coupled device situated to receive the focused filtered reflected light.

10. A wheel balancer as in claim 1, wherein said light sensing means comprises a light sensitive camera, and wherein said means coupled to receive said signals responsive to reflected light comprises a vision system for providing said data relating to wheel rim/tire assembly feature locations, dimensions and physical configuration.

11. A wheel balancer as in claim 1, wherein said light sensing means comprises a two-dimensional charge coupled device array, and wherein said means coupled to receive said signals responsive to reflected light comprises an analog to digital converter providing a digital output, a memory store coupled to receive said digital output, and a microprocessor for accessing said memory store and providing said data relating to wheel rim/tire assembly feature locations, dimensions and physical configuration.

12. A wheel balancer as in claim 1, wherein said light sensing means comprises a two dimensional light sensing array, and wherein said means coupled to receive said signals responsive to reflected light comprises an analog to digital converter, and a processor for providing said data relating to wheel rim/tire assembly feature locations, dimensions and physical configuration.

13. A wheel rim/tire assembly parameter measurement apparatus for a dynamic wheel balancer as in claim 1 wherein said light beam projection means comprises first and second light beam projection means, and wherein said light sensing means comprises first and second light sensing means exposed to light reflected from the area on the rim/tire assembly impinged by the converted light beam from said first and second light beam projection means respectively.

14. Runout measurement apparatus for detecting runout in a rotatable member relative to a spin axis for the rotating member, comprising

light beam projection means for projecting a light beam along a path toward the rotatable member,

optical means for converting said light beam into a substantially planar beam,

light sensing means disposed to receive light from said substantially planar beam which is reflected from the rotatable member, said light sensing means providing an output signal indicative of said planar beam reflection, and

signal processing means coupled to said output signal for producing data representing a measurement of change in peripheral position of the rotatable member as it is rotated about the spin axis.

15. Runout measurement apparatus as in claim 14 wherein the rotatable member is a brake disc, and wherein said spin axis is defined by the spindle of a brake disc lathe, and wherein said light beam projection means comprises a beam splitter for splitting said light beam, and reflector means, each of said beam splitter and said reflector means functioning to direct a portion of said split light beam toward opposing sides of said brake disc.

16. Runout measurement apparatus as in claim 15 wherein said light beam projection means further comprises a laser light source.

17. Runout measurement apparatus as in claim 15 wherein said light beam projection means further comprises a white light source, and wherein said optical means comprises a collimator interposed in the path of said light beam from said white light source, and a cylindrical lens interposed in the path of the said light beam from said collimator.

18. Runout measurement apparatus as in claim 15 wherein said light sensing means comprises a band pass filter receiving the reflected light and passing filtered reflected light, a lens exposed to and operating to focus the filtered reflected light, and a charge coupled device situated to receive the focused filtered reflected light.

19. Runout measurement apparatus as in claim 14 wherein said rotatable member is a wheel rim/tire assembly mounted on a vehicle being subjected to wheel alignment, and wherein said spin axis is defined by the spindle on which said wheel rim/tire assembly is mounted, said light beam projection means comprising means for mounting said light beam projection means to illuminate the periphery of the wheel rim/tire assembly with said light beam.

20. Runout measurement apparatus as in claim 19 wherein the wheel has an inner rim and an outer rim, and wherein said light beam projection means comprises means for mounting said light beam projection means to illuminate said inner and outer rims with said light beam.

21. Runout measurement apparatus as in claim 20 wherein said light beam projection means comprises a beam splitter for splitting said light beam and reflector means, each of said beam splitter and reflector means functioning to direct a portion of said slit light beam toward one of the inner and outer rims respectively.

22. Runout measurement apparatus as in claim 19 wherein the wheel has an inner rim and an outer rim and wherein said light beam projection means comprises means for mounting said light beam projection means to illuminate the inner and outer rims and the periphery of the wheel rim/tire assembly with said light beam.

23. Runout measurement apparatus as in claim 19 wherein said light beam projection means comprises a laser light source.

24. Runout measurement apparatus as in claim 19 wherein said light beam projection means comprises a white light source, and wherein said optical means comprises a collimator interposed in the path of said light beam from said white light source, and a cylindrical lens interposed in the path of said light beam from said collimator.

25. Runout measurement apparatus as in claim 19 wherein said light sensing means comprises a band pass filter receiving the reflected light an passing filtered reflected light, a lens exposed to and operating to focus the filtered reflected light, and a charge coupled device situated to receive the focused filtered reflected light.

26. Apparatus for determining the physical configuration of a body mounted for rotating motion on a spindle, comprising

light beam projection means for projecting a light beam along a path directed toward the body on the spindle,

optical means for converting said light beam into a beam contained substantially in a single plane and therefore called a planar light beam,

light sensing means exposed to light reflected from the portion of the mounted body impinged by the planar light beam for providing output signals responsive thereto, and

means coupled to said light sensing means for processing said signals to provide data related to the body configuration.

27. Apparatus as in claim 26 comprising means for calibrating said light sensing means output signals, whereby said data relating to the body configuration is scaled to provide actual distances and locations in the body configuration.

28. Apparatus as in claim 26 wherein said body is a brake member having a friction surface thereon and said spindle is defined by a brake lathe, said light beam projection means comprising means for mounting said light beam projection means to illuminate the friction surface of said brake member with said light beam.

29. Apparatus as in claim 28 wherein said light beam projection means comprises a beam splitter for splitting said light beam, and reflector means, each of said beam splitter and said reflector means functioning to direct a portion of said split light beam towards opposite sides of said brake member friction surfaces.

30. Apparatus as in claim 28 wherein said light beam projection means comprises a laser light source.

31. Apparatus as in claim 28 wherein said light beam projection means comprises a white light source, and wherein said optical means comprises a collimator interposed in the path of said light beam from said white light source, and a cylindrical lens interposed in the path of said light beam from said collimator.

32. Apparatus as in claim 28 wherein said light sensing means comprises a band pass filter receiving the reflected light and passing filtered reflected light, a lens exposed to and operating to focus the filtered reflected light, and a charge coupled device situated to receive the focused filtered reflected light.

33. Apparatus as in claim 26 wherein said body is a vehicle wheel mounted on a vehicle wheel spindle situated to be accessed by a wheel alignment system, said light beam projection means comprising means for mounting said light beam projection means to illuminate the periphery of the vehicle wheel with said light beam.

34. Apparatus as in claim 33 wherein said light beam projection means comprises a laser light source.

35. Apparatus as in claim 33 wherein said light beam projection means comprises a white light source, and wherein said optical means comprises a collimator interposed in the path of said light beam from said white light source, and a cylindrical lens interposed in the path of said light beam from said collimator.

36. Apparatus as in claim 33 wherein said light sensing means comprises a band pass filter receiving the reflected light and passing filtered reflected light, a lens exposed to and operating to focus the filtered reflected light, and a charge coupled device situated to receive the focused filtered reflected light.

37. Apparatus as in claim 26 wherein said body is a wheel rim and wherein said spindle extends from a wheel balancer, said light beam projection means comprising means for mounting said light beam projection means to illuminate the periphery of the wheel rim with said light beam.

38. Apparatus as in claim 37 wherein the wheel rim has an inner rim and an outer rim and wherein said light beam projection means comprises means for mounting said light beam projection means to illuminate said inner and outer rims with said light beam.

39. Apparatus as in claim 37 wherein said light beam projection means comprises a beam splitter for splitting said light beam, and reflector means, each of said beam splitter and said reflector means functioning to direct a portion of said split light beam toward one of the inner and outer rims respectively.

40. Apparatus as in claim 37 wherein said light beam projection means comprises a laser light source.

41. Apparatus as in claim 37 wherein said light beam projection means comprises a white light source, and wherein said optical means comprises a collimator interposed in the path of said light beam from said white light source, and a cylindrical lens interposed in the path of said light beam from said collimator.

42. Apparatus as in claim 37 wherein said light sensing means comprises a band pass filter receiving the reflected light and passing filtered reflected light, a lens exposed to and operating to focus the filtered reflected light, and a charge coupled device situated to receive the focused filtered reflected light.

43. A method of determining specific physical characteristics and features of a body which has some known general body characteristics and features, the body being mounted for rotational motion on a spindle having a known body coordinate system, comprising the steps of

directing a planar light array toward the body from a known direction relative to the body coordinate system,

detecting the impingement of said light array on the body from a known direction relative to said planar light array known direction,

calibrating the detecting impingement of said light array for distances and locations in the known body coordinate system, and

transforming the calibrated detected impingement into discrete distances and positions in the known body coordinate system, wherein the positions of the specific physical characteristics and features of the body are established in the body coordinate system.

44. A method as in claim 43 wherein the step of transforming comprises the steps of

calculating the positions of the detected impingement in a coordinate system with known orientation relative to the planar light array,

transforming the positions in the planar light array coordinate system into the known body coordinate system, and

extracting body feature data for use in determining the body physical characteristics.

45. A method as in claim 43 wherein the step of detecting comprises the steps of

sensing the positions of impingement along the intersection of the planar light array and the body in two dimensions, and

calculating the positions within a coordinate system having known orientation relative to the planar light array known direction.