Scale-bar artifact and methods of use

• US 20020148133A1
• Filed: 03/06/2002
• Published: 10/17/2002
• Est. Priority Date: 03/06/2001
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Acquisition, LLC
• Inventors: Bridges, Robert E., Cramer, Peter G., West, James K.
• Granted Patent: US 6,964,113 B2
• Time in Patent Office: Days
• US Class Current: 33/702
• CPC Class Codes: G01B 11/02 for measuring length, width or thickness G01B11/08 takes precedence
• CPC Class Codes: G01B 21/042 Calibration or calibration artifacts G01B3/30, G01B9/02072 take precedence
• CPC Class Codes: G01B 5/0014 due to temperature on machine tools B23Q11/0003
• CPC Class Codes: G01B 7/02 for measuring length, width or thickness G01B7/004, G01B7/12 take precedence

Abstract

A scale-bar artifact is and measurement method is provided, the artifact comprising a shaft, at least one mounting nest positioned on the shaft, a plurality of target nests positioned on the shaft, at least one temperature sensor in contact with the material of the shaft and a computer or circuit board in communication with the at least one temperature sensor, wherein the computer or circuit board is configured to receive temperature sensor data and to compile temperature corrected distance measurements corresponding to at least one linear portion of the shaft. Additionally, a scale-bar artifact is provided, comprising a shaft, a plurality of target nests positioned on the shaft and at least one mounting nest positioned on the shaft, wherein the at least one mounting nest comprises either at least one adjustable kinematic mounting nest or at least one fixed kinematic mounting nest configured to receive a separate mounting component. Methods for measuring temperature compensation values of a scale-bar and for accurately measuring scale-bar length with a tracker interferometer are also described.

Claims

1. A scale-bar artifact, comprising:

a shaft;

at least one mounting nest positioned on the shaft;

a plurality of target nests positioned on the shaft;

at least one temperature sensor in contact with the material of the shaft; and

a computer or circuit board in communication with the at least one temperature sensor, wherein the computer or circuit board is configured to receive temperature sensor data and to compile temperature corrected distance measurements corresponding to at least one linear portion of the shaft.

2. The scale-bar artifact of claim 1, wherein at least one of temperature sensor is a thermister placed in series with a voltage reference and a known resistance.

3. The scale-bar artifact of claim 1, wherein at least one temperature sensor is provided within a small hole in the shaft.

4. The scale-bar artifact of claim 3, wherein the at least one temperature sensor is encapsulated in epoxy.

5. The scale-bar artifact of claim 1, wherein a plurality of temperature sensors are spaced in about even distances along the shaft.

6. The scale-bar artifact of claim 1, wherein the at least one temperature sensor is connected to a circuit board having an output.

7. The scale-bar artifact of claim 6, wherein the circuit board comprises one or more of a voltage regulator, a nonvolatile memory, a digital-signal processing module and a communication transceiver.

8. The scale-bar artifact of claim 6, wherein the output is configured to communicate with a separate computer, interferometer or coordinate measuring device, and wherein the sensor output relays at least one temperature value for at least one sensor position along the shaft, or wherein the output relays temperature corrected distance measurements corresponding to at least one linear portion of the shaft.

9. The scale-bar artifact of claim 1, wherein the at least one temperature sensor is embedded within the material of the scale-bar shaft.

10. The scale-bar artifact of claim 1, wherein the one or more of the shaft, at least one mounting nest and plurality of target nests comprise an aluminum material.

11. The scale-bar artifact of claim 1, wherein at least two target nests are spaced at a known interval as a function of temperature.

12. The scale-bar artifact of claim 1, wherein the scale-bar artifact comprises a plurality of mounting nests positioned on the shaft.

13. The scale-bar artifact of claim 1, wherein the plurality of target nests are configured to receive one or more of a spherically mounted mirror, a crosshair target, a spherically mounted retroreflector and a beamsplitter.

14. The scale-bar artifact of claim 1, wherein the plurality of target nests are magnetic target nests

15. The scale-bar artifact of claim 1, wherein the mounting nests further comprise at least one fixed kinematic mounting nest configured to receive a separate mounting component.

16. The scale-bar artifact of claim 15, wherein the at least one fixed kinematic mounting nest further comprises a mechanical attachment mechanism attached thereto, the mechanical attachment mechanism configured to engage a portion of a separate component.

17. The scale-bar artifact of claim 16, wherein the mechanical attachment is detachably attached to the at least one fixed kinematic mounting nest.

18. The scale-bar artifact of claim 16, wherein the mechanical attachment is at least one strap configured to attach or otherwise adhere to a body of a separate mounting component.

19. The scale-bar artifact of claim 15, wherein the separate mounting component comprises a one dimensional adjustable mount having a spherical mounting surface.

20. The scale-bar artifact of claim 15, wherein the separate mounting component comprises a two dimensional adjustable mount having a spherical mounting surface.

21. The scale-bar artifact of claim 20, wherein the spherical mounting surface is a ferromagnetic mounting surface.

22. The scale-bar artifact of claim 20, wherein the two dimensional adjustable mount further comprises a selectively magnetic base and a switch, wherein the switch enables or disables the magnetism of the base.

23. The scale-bar artifact of claim 15, wherein the at least one fixed kinematic mounting nest comprises a body supporting a plurality of kinematic spheres configured to receive a spherical surface of a separate mounting component.

24. The scale-bar artifact of claim 23, wherein the plurality of kinematic spheres prohibit contact of the spherical surface with the body of the at least one fixed kinematic mounting nest.

25. The scale-bar artifact of claim 23, wherein the kinematic spheres comprise a thermally insulating material.

26. The scale-bar artifact of claim 25, wherein the kinematic spheres comprise a ceramic material.

27. The scale-bar artifact of claim 23, wherein the at least one fixed kinematic mounting nest further comprises a magnetic component, and wherein the spherical surface of the separate mounting component comprises a ferromagnetic material.

28. The scale-bar artifact of claim 23, wherein the at least one fixed kinematic mounting nest comprises a body supporting three kinematic spheres configured to receive a spherical surface of a separate mounting component.

29. The scale-bar artifact of claim 1, wherein the mounting nests comprise at least one adjustable kinematic mounting nest configured to receive a separate mounting component.

30. The scale-bar artifact of claim 29, wherein the at least one adjustable kinematic mounting nest is configured to adjust along a line.

31. The scale-bar artifact of claim 30, wherein the at least one adjustable kinematic mounting nest is configured to adjust along a line from a central position to about 12 to about 25 millimeters in either direction along the line.

32. The scale-bar artifact of claim 30, wherein the at least one adjustable kinematic mounting nest is configured to slide along a linear track or base.

33. The scale-bar artifact of claim 29, wherein the at least one adjustable kinematic mounting nest comprises a body supporting a plurality of kinematic spheres configured to receive a spherical surface of a separate mounting component.

34. The scale-bar artifact of claim 33, wherein the plurality of kinematic spheres prohibit contact between the spherical surface of the separate mounting component and the body of the adjustable kinematic mounting nest.

35. The scale-bar artifact of claim 33, wherein the kinematic spheres comprise a thermally insulating material.

36. The scale-bar artifact of claim 35, wherein the kinematic spheres comprise a ceramic material.

37. The scale-bar artifact of claim 33, wherein the separate mounting component comprises a spherical surface supported by a body provided on an adjustable clamp, and wherein the adjustable clamp is configured to attach to a rigid structure.

38. The scale-bar artifact of claim 33, wherein the at least one adjustable kinematic mounting nest further comprises a magnetic component, and wherein the spherical surface of the separate mounting component comprises a ferromagnetic material.

39. The scale-bar artifact of claim 29, wherein the at least one adjustable kinematic mounting nest comprises a body supporting three kinematic spheres configured to receive a spherical surface of a separate mounting component.

40. The scale-bar artifact of claim 1 further comprising at least one separate mounting component, wherein the at least one separate mounting component is provided on a rigid structure and comprises at least one spherical mounting surface configured to engage at least one of the mounting nests.

41. The scale-bar artifact of claim 40, wherein the rigid structure is an instrument stand, and wherein the instrument stand has at least one vertically adjustable component.

42. The scale-bar artifact of claim 40, further comprising a reference interferometer attached to the rigid structure.

43. The scale-bar artifact of claim 1, further comprising an air temperature sensor positioned on the shaft.

44. A scale-bar artifact, comprising:

a shaft;

a plurality of target nests spaced along the shaft; and

at least one mounting nest provided on the shaft, wherein at least one mounting nest comprises at least one fixed kinematic mounting nest configured to receive a separate mounting component.

45. The scale-bar artifact of claim 44, wherein at least one mounting nest comprises at least one adjustable kinematic mounting nest configured to receive a separate mounting component.

46. The scale-bar artifact of claim 44, wherein the at least one fixed kinematic mounting nest further comprises a mechanical attachment mechanism attached thereto configured to engage a portion of a separate component.

47. The scale-bar artifact of claim 46, wherein the mechanical attachment is detachably attached to the at least one fixed kinematic mounting nest.

48. The scale-bar artifact of claim 46, wherein the mechanical attachment is at least one strap configured to attach or otherwise adhere to a body of a separate mounting component.

49. The scale-bar artifact of claim 44, wherein the separate mounting component comprises a one dimensional adjustable mount having a spherical mounting surface.

50. The scale-bar artifact of claim 44, wherein the separate mounting component comprises a two dimensional adjustable mount having a spherical mounting surface.

51. The scale-bar artifact of claim 50, wherein the spherical mounting surface is a ferromagnetic surface.

52. The scale-bar artifact of claim 50, wherein the two dimensional adjustable mount further comprises a selectively magnetic base and switch, wherein the switch enables or disables the magnetism of the base.

53. The scale-bar artifact of claim 44, wherein the at least one fixed kinematic mounting nest comprises a body supporting a plurality of kinematic spheres configured to receive a spherical surface of a separate mounting component.

54. The scale-bar artifact of claim 53, wherein the plurality of kinematic spheres prohibit contact of the spherical surface with the body of the at least one fixed kinematic mounting nest.

55. The scale-bar artifact of claim 53, wherein the kinematic spheres comprise a thermally insulating material.

56. The scale-bar artifact of claim 55, wherein the kinematic spheres comprise a ceramic material.

57. The scale-bar artifact of claim 53, wherein the at least one fixed kinematic mounting nest further comprises a magnetic component, and wherein the spherical surface of the separate mounting component comprises a ferromagnetic material.

58. The scale-bar artifact of claim 53, wherein the at least one fixed kinematic mounting nest comprises a body supporting three kinematic spheres configured to receive a spherical surface of a separate mounting component.

60. The scale-bar artifact of claim 59, wherein the at least one adjustable kinematic mounting nest is configured to adjust along a line.

61. The scale-bar artifact of claim 60, wherein the at least one adjustable kinematic mounting nest is configured to adjust along a line from a central position to about 12 to about 25 millimeters in either direction along the line.

62. The scale-bar artifact of claim 60, wherein the at least one adjustable kinematic mounting nest is configured to slide along a linear track or base.

63. The scale-bar artifact of claim 59, wherein the at least one adjustable kinematic mounting nest comprises a body supporting a plurality of kinematic spheres configured to receive a spherical surface of a separate mounting component.

64. The scale-bar artifact of claim 63, wherein the plurality of kinematic spheres prohibit contact between the spherical surface of the separate mounting component and the body of the adjustable kinematic mounting nest.

65. The scale-bar artifact of claim 63, wherein the kinematic spheres comprise a thermally insulating material.

66. The scale-bar artifact of claim 65, wherein the kinematic spheres comprise a ceramic material.

67. The scale-bar artifact of claim 63, wherein the separate mounting component comprises a spherical surface supported by a body provided on an adjustable clamp, and wherein the adjustable clamp configured to attach to a rigid structure.

68. The scale-bar artifact of claim 63, wherein the at least one adjustable kinematic mounting nest further comprises a magnetic component, and wherein the spherical surface of the separate mounting component comprises a ferromagnetic material.

69. The scale-bar artifact of claim 59, wherein the at least one adjustable kinematic mounting nest comprises a body supporting three kinematic spheres configured to receive a spherical surface of a separate mounting component.

70. The scale-bar artifact of claim 59, further comprising at least one separate mounting component, wherein the at least one separate mounting component is provided on a rigid structure and comprises at least one spherical mounting surface configured to engage at least one of the mounting nests.

71. The scale-bar artifact of claim 70, wherein the rigid structure is an instrument stand, and wherein the instrument stand has at least one vertically adjustable component.

59. A scale-bar artifact, comprising:

a shaft; and

a plurality of target nests positioned on the shaft; and

at least one mounting nest positioned on the shaft, wherein at least one mounting nest comprises at least one adjustable kinematic mounting nest configured to receive a separate mounting component.

72. A method for accurately measuring scale-bar length with a tracker interferometer, comprising:

tracking a spherically mounted retroreflector to a target nest on a scale-bar artifact with a tracker interferometer;

with tracking disengaged, replacing the spherically mounted retroreflector with a spherically mounted mirror;

adjusting the spherically mounted mirror such that a reflected laser beam targets a reference object on a second scale-bar artifact target nest;

positioning a spherically mounted retroreflector on a third scale-bar artifact target nest positioned between the first and third scale-bar artifact target nests; and

while maintaining the position of the spherically mounted mirror, measuring the distances between the third and at least one additional scale-bar artifact target nest with the tracker interferometer.

73. A method for measuring temperature compensation values of a scale-bar, comprising:

aligning a laser beam of a laser tracker having a tracking interferometer such that the laser beam intersects a spherically mounted retroreflector positioned on a first target nest of a scale-bar artifact;

measuring the distance between the first target nest of the scale-bar artifacts and at least one additional target nest of the scale-bar artifact using the tracking interferometer;

aligning a reference interferometer such that a laser beam passes from the reference interferometer through a beam-splitter and retroreflector assembly, positioned in a target nest of the scale-bar artifact, to a spherically mounted retroreflector, positioned in a target nest of the scale-bar artifact, and such that the laser beam is reflected back to the reference interferometer; and

increasing the temperature of the scale-bar artifact while monitoring changes in scale-bar length.

74. The method in accordance with claim 73, further comprising reading the temperature of the scale-bar artifact with an air-temperature sensor.

75. The method in accordance with claim 73, further comprising monitoring the temperature of the scale-bar using at least one temperature sensor in contact with the material of the scale-bar and provided on scale-bar.