Coordinate measuring system

• US 6,543,149 B1
• Filed: 10/17/2000
• Issued: 04/08/2003
• Est. Priority Date: 12/02/1999
• Status: Expired due to Fees

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Carlisle, Keith
• Primary Examiner(s): BENNETT, GEORGE B
• Application Number:
  US09/690,930
• Time in Patent Office: 903 Days
• Field of Search: 335/03, 336/45, 337/06, 337/07, 337/08
• US Class Current: 33/503
• CPC Class Codes: C12N 2501/385 of the family of the retinoic acid recptor, e.g. RAR, RXR; Peroxisome proliferator-activated receptor [PPAR]
• CPC Class Codes: G01B 5/285 for controlling eveness

Abstract

An apparatus and method is utilized to measure relative rigid body motion between two bodies by measuring linear motion in the principal axis and linear motion in an orthogonal axis. From such measurements it is possible to obtain displacement, departure from straightness, and angular displacement from the principal axis of a rigid body.

Claims

1. A system comprising:

a first periodic measurement scale assembly substantially aligned with a first axis; and

a first plurality of sensors positioned substantially proximate to said first periodic measurement scale assembly, said first plurality of sensors including a pair of sensors spaced from each other along the first axis and configured to cooperatively measure at least one of departure from straightness of a first effective point from the first axis and angular displacement of the first effective point from the first axis.

2. The system of claim 1,

wherein said first plurality of sensors includes at least one sensor configured to measure linear displacement of the first effective point along the first axis.

3. The system of claim 1, further comprising:

a second periodic measurement scale assembly substantially aligned with a second axis substantially orthogonal to said first axis; and

a second plurality of sensors positioned substantially proximate to said second periodic measurement scale assembly, said second plurality of sensors including at least one sensor configured to measure linear displacement of a second effective point along the second axis, and a pair of sensors spaced from each other along the second axis and configured to cooperatively measure at least one of departure from straightness of the second effective point from the second axis, and angular displacement of the second effective point from the second axis.

4. The system of claim 2,

wherein only one of said first plurality of sensors is configured to measure linear displacement of the first effective point along the first axis.

5. The system of claim 1,

wherein the position of said first effective point indicates a position of a functional point of a rigid body.

6. The system of claim 2,

wherein said first periodic measurement scale assembly has a first plurality of marks extending in a first direction substantially parallel to the first axis, and a second plurality of marks extending in a second direction substantially orthogonal to the first axis, the second plurality of marks for use in the cooperative measurement of the departure from straightness and angular displacement by the pair of sensors.

7. The system of claim 6,

wherein said plurality of first marks extending in said first direction are bounded on both sides by the second plurality of marks extending in the second direction.

8. The system of claim 1,

wherein said first plurality of sensors are mounted on a first assembly.

9. The system of claim 8, wherein said first assembly is mounted on a first mounting member;

and

said first mounting member adapted to attach to a rigid body.

10. The system of claim 1, wherein said sensors are transducers.

11. A measuring device comprising:

a first scale assembly having a plurality of first periodic measurement scales substantially aligned with a first axis; and

a first plurality of pairs of sensors positioned in substantial proximity to said first scale assembly, said first plurality of pairs of sensors including a first pair of sensors spaced from each other along the first axis and configured to cooperatively measure departure from straightness of a first effective point from the first axis.

12. The measuring device of claim 11,

wherein said first plurality of pairs of sensors includes a second pair of sensors spaced from each other along the first axis and configured to cooperatively measure linear displacement of the first effective point along the first axis and a third pair of sensors spaced from each other along the first axis and configured to cooperatively measure angular displacement of the first effective point from the first axis.

13. The measuring device of claim 11,

wherein each of said first periodic measurement scales are separated by a gap.

14. The measuring device of claim 13,

wherein each of said first plurality of pairs of sensors are configured to perform a handshaking function as one of each of the pairs of sensors passes over each of said gaps.

15. The measuring device of claim 13,

wherein one of each of said first plurality of pairs of sensors are configured to monitor said plurality of first periodic measurement scales as the other pair of said first plurality of pairs of sensors passes over said gaps.

16. The measuring device of claim 11, further comprising:

a second scale assembly having a plurality of second periodic measurement scales substantially aligned with a second axis substantially orthogonal to the first axis; and

a second plurality of pairs of sensors positioned substantially proximate to said second plurality of periodic measurement scales, said second plurality of pairs of sensors including a fourth pair of sensors spaced from each other along the second axis and configured to cooperatively measure linear displacement of a second effective point along the second axis, a fifth pair of sensors spaced from each other along the second axis and configured to cooperatively measure departure from straightness of the second effective point from the second axis, and a sixth pair of sensors spaced from each other along the second axis and configured to cooperatively measure angular displacement of the second effective point from the second axis.

17. The measuring device of claim 12,

wherein each pair of said first and third pairs of sensors are separated by a distance of greater than about six inches.

18. The measuring device of claim 12,

wherein each pair of said first and third pairs of sensors are separated by a distance greater than the distance from the effective point to a functional point of a rigid body.

19. The measuring device of claim 11, further comprising:

a control system containing software programmed to perform an offset operation on data collected from said first plurality of pairs of sensors.

20. The measuring device of claim 11, further comprising:

a control system containing software programmed to perform a handshake function during periods when one of said first plurality of pairs of sensors is located over a gap in the plurality of first periodic measurement scales.

21. A position measuring device comprising:

a plurality of first periodic measurement scales substantially aligned with a first axis; and

a first plurality of sensors positioned substantially proximate to said plurality of first periodic measurement scales, said first plurality of sensors including at least one sensor configured to measure linear displacement of a first effective point along the first axis, and a pair of sensors spaced from each other along the first axis and configured to cooperatively measure departure from straightness of the first effective point from the first axis, and angular displacement of the first effective point from the first axis.

22. A machine tool comprising:

a first scale assembly having a first periodic measurement scale aligned with a first axis; and

a firs plurality of sensors positioned in proximity to said first scale assembly, said first plurality of sensors including a pair of sensors spaced from each other along the first axis and configured to cooperatively measure at least one of departure from straightness of a first effective point from the first axis and angular displacement of the first effective point from the first axis.

23. The machine tool of claim 22, further comprising:

a second scale assembly having a second periodic measurement scale substantially aligned with a second axis substantially orthogonal to said first axis; and

a second plurality of sensors positioned substantially proximate to said second scale assembly, said second plurality of sensors including at least one sensor configured to measure linear displacement of a second effective point along the second axis, and a pair of sensors spaced from each other along the second axis and configured to cooperatively measure at least one of departure from straightness of the second effective point from the second axis, and angular displacement of the second effective point from the second axis.

24. The machine tool of claim 23,

wherein said first and second periodic measurement scale assemblies are substantially orthogonal.

25. A method comprising:

measuring at least one of departure from straightness of a first effective point from a first axis and angular displacement of the first effective point from the first axis, by cooperatively utilizing a pair of sensors spaced from each other along the first axis and positioned substantially proximate a first scale assembly substantially aligned with said first axis.

26. The method of claim 25, further comprising:

measuring linear displacement of the first effective point along the first axis by using at least one sensor positioned substantially proximate said first scale assembly.

27. The method of claim 26, further comprising:

measuring linear displacement of a second effective point along a second axis using at least one sensor positioned substantially proximate a second scale assembly;

measuring at least one of departure from straightness of the second effective point from the second axis and angular displacement of the second effective point from the second axis, by cooperatively using a pair of sensors spaced from each other along the second axis and positioned substantially proximate said second scale assembly.

28. The method of claim 26, wherein said first scale assembly has gradations aligned with said first axis and gradations substantially orthogonal to said first axis.

29. A method of determining the position of a rigid body comprising:

measuring linear displacement of a first effective point along a plurality of measurement scales substantially aligned along a first axis by cooperatively using a first pair of sensors positioned substantially proximate said plurality of measurement scales; and

measuring at least one of departure from straightness of the first effective point from the first axis and angular displacement of the first effective point from the first axis, by cooperatively using a second pair of sensors spaced apart from each other along the first axis and positioned substantially proximate said plurality of measurement scales.

30. The method of claim 29,

wherein said first, and second pairs of sensors are substantially aligned with each other.

31. The method of claim 29,

wherein said plurality of measurement scales have gradations substantially aligned with said first axis and gradations substantially orthogonal to said first axis.

32. The method of claim 29, further comprising:

performing a handshake function when one of said first and second pairs of sensors passes over one of a plurality of gaps located between said plurality of measurement scales.

33. The method of claim 29, further comprising:

performing an offset calculation in a controller to relate the position of the first effective point to a functional point on said rigid body.

34. An apparatus comprising:

means for measuring at least one of departure from straightness and angular displacement of a first effective point from a first axis by cooperatively using a pair of sensors spaced from each other along said first axis and positioned substantially proximate a first scale assembly substantially aligned with said first axis.

35. The apparatus of claim 34, further comprising:

means for measuring linear displacement of the first effective point along the first axis by using at least one sensor positioned substantially proximate said first scale assembly.

36. The apparatus of claim 34, further comprising:

means for measuring linear displacement of a second effective point along a second axis by using at least one sensor positioned substantially proximate a second scale assembly; and

means for measuring at least one of departure from straightness and angular displacement of the second effective point from the second axis by cooperatively using a pair of sensors positioned substantially proximate said second scale assembly.

37. The apparatus of claim 34,

wherein said first scale assembly has gradations aligned with said first axis and gradations substantially orthogonal to said first axis.

38. A measuring device comprising:

means for measuring linear displacement of a first effective point along a plurality of measurement scales aligned along a first axis by using a first pair of sensors positioned substantially proximate said plurality of measurement scales; and

means for measuring at least one of departure from straightness of the first effective point from the first axis and angular displacement of the first effective point from the first axis by cooperatively using a second pair of sensors positioned substantially proximate said plurality of measurement scales.

39. The measuring device of claim 38, wherein said first, and second pairs of sensors are substantially aligned with each other on a first assembly.

40. The measuring device of claim 38,

wherein said plurality of measurement scales have gradations substantially aligned with said first axis and gradations substantially orthogonal to said first axis.

41. The measuring device of claim 38, wherein the first pair of sensors are configured to perform a handshake function when one of said first pair of sensors passes over one of a plurality of gaps located between said plurality of measurement scales.

42. The measuring device of claim 38, further comprising:

means for performing an offset calculation in a controller to relate the position of the first effective point to a functional point on a rigid body.

43. A system comprising:

first means for measuring a position of a rigid body relative to a reference body; and

second means for measuring a position of an object relative to the reference body, with said object configured to act upon said rigid body

wherein said second means is configured to compensate for errors in the position of the rigid body relative to the object.

44. A system comprising:

a first scale assembly substantially aligned with a first axis;

a second scale assembly substantially aligned with a second axis substantially orthogonal to the first axis;

a first slide assembly having at least one sensor and designed to travel along and substantially proximate to said first scale assembly;

a second slide assembly separate from the first slide assembly, and having at least one sensor and designed to travel along and substantially proximate to said second scale assembly; and

a control system configured to utilize data from said at least one sensor on said second slide assembly to compensate for errors in the positioning of a first effective point on the first slide assembly.

45. The system of claim 44,

wherein said first effective point is designed to correspond to the position of a functional point on a rigid body.

46. The system of claim 45,

wherein said second slide assembly is designed to indicate the position of a tool operating on said rigid body.

47. The system of claim 44,

wherein the control system is configured to utilized data from said at least one sensor on said first slide assembly to compensate for errors in the positioning of a second effective point on the second slide assembly.

48. A system comprising:

a first scale assembly having a plurality of first periodic measurement scales substantially aligned with a first axis;

a first plurality of pairs of sensors positioned substantially proximate to said first scale assembly said first plurality of pairs of sensors including at least one sensor configured to measure linear displacement of the first effective point along the first axis, and a pair of sensors spaced apart from each other and configured to cooperatively measure at least one of departure from straightness of a first effective point from the first axis and angular displacement of the first effective point from the first axis;

a second scale assembly having a plurality of periodic measurement scales aligned with a second axis;

a second plurality of pairs of sensors positioned substantially proximate to said second plurality of periodic measurement scales, said second plurality of pairs of sensors including at least one sensor configured to measure linear displacement of a second effective point along the second axis, and a pair of sensors spaced apart from each other and configured to cooperatively measure at least one of departure from straightness of the second effective point from the second axis, and angular displacement of the second effective point from the second axis; and

wherein said second plurality of pairs of sensors are configured to compensate for errors in the positioning of a rigid body.