Measurement of spatial coordinates

• US 7,145,647 B2
• Filed: 02/11/2004
• Issued: 12/05/2006
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Metroner ASA
• Original Assignee: Metronor ASA
• Inventors: Røtvold, Øyvind, Amdal, Knut, Suphellen, Harald
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Ratcliffe, Luke D.
• Application Number:
  US10/779,169
• Publication Number:
  US 20040160594A1
• Time in Patent Office: 1,028 Days
• Field of Search: 356/141.1
• US Class Current: 356/141.1
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates

Abstract

A system for measurement of spatial coordinates comprising a probing tool and a main measuring unit, wherein said probing tool comprises a reflective object element, observation mechanism located in a known position and orientation relative to said reflective object element and capable of observing targets; and wherein said main measuring unit comprises a distance measuring device capable of measuring a distance from said device to said reflective object element; a mechanism constructed and adapted to direct a measuring beam from said distance measuring device to said reflective object element; a direction determining mechanism constructed and adapted to determine a direction of a measuring beam; at least two targets located in known positions relative to said distance measuring device, whereby the orientation of said reflective object element can be determined from observations of said targets by said observation mechanism.

Claims

1. A system for measurement of spatial coordinates, the system comprising a probing tool, a main measuring unit, and at least two targets located in known positions relative to said distance measuring device, said probing tool disconnected from said measuring unit, wherein said probing tool comprises:

a) a reflective object element,

b) an observation mechanism located in a known position and orientation relative to said reflective object element and capable of observing said at least two targets,

c) an offset mechanism connected to said reflective object element for measuring points other than the center of said reflective object element by using a know orientation and position of said reflective object element, wherein said offset mechanism is connected with said reflective object element and with said observation mechanism via a mechanism constructed for relative rotation, said mechanism including a mechanism constructed and adapted to measure said rotation;

and wherein said main measuring unit comprises;

d) a distance measuring device constructed and adapted to measure a distance from said device to said reflective object element; and

e) a direction determining mechanism constructed and adapted to determine a direction of a measuring beam;

whereby

the orientation of said reflective object element can be determined from observations of said targets by said observation mechanism, using the direction of the measuring beam and the distance from the measuring device to the reflective object element.

2. A system for the measurement of spatial coordinates according to claim 1, wherein said offset mechanism is a mechanical probe or stylus constructed and adapted to be held in contact with points to be measured.

3. A system for measurement of spatial coordinates according to claim 1, wherein said mechanism constructed for relative rotation comprises:

a gimbals arrangement.

4. A system for measurement of spatial coordinates according to claim 1, wherein said observation mechanism comprises:

a zoom lens, and

apparatus for controlling said zoom lens in order to limit the field of view to that necessary to observe said at least two targets.

5. A system for the measurement of spatial coordinates according to claim 1, wherein said offset mechanism is a device for measuring distance and direction relative to said reflective object element.

6. A system for the measurement of spatial coordinates according to claim 1, wherein said offset mechanism is a surface scanning device for simultaneously measuring a plurality of points relative to said reflective object element.

7. A system for the measurement of spatial coordinates according to claim 1, wherein said observation mechanism comprises one or more cameras.

8. A system for the measurement of spatial coordinates according to claim 1, wherein said observation mechanism comprises one or more one-dimensional linear array cameras.

9. A system for measurement of spatial coordinates according to claim 1, wherein said targets are selected from the group of passive targets including but not limited to simple measurement marks, cross-hairs;

retro-reflective targets; and

coded retro-reflective targets.

10. A system for measurement of spatial coordinates according to claim 1, wherein said targets are active light-emitting targets including but not limited to light-emitting diodes (LEDs).

11. A system for measurement of spatial coordinates according to claim 1, wherein said targets are represented by predetermined features or shape elements comprising said features inherent in known objects or classes of objects.

12. A system for measurement of spatial coordinates according claim 1, wherein said distance measuring device is part of a laser tracker.

13. A system according to claim 1 for measuring the relative spatial position and orientation of an object, wherein the reflective object element with observation mechanism is placed in a known relationship to an object, in such a way that changes observed in position and orientation of the reflective object element correspond to the changes in position and orientation for the object.

14. The use of the system according to claim 1 for measuring the relative spatial position and orientation of a first object and a second object, comprising:

placing the reflective object element with observation mechanism in a known relationship to the second object,

positioning a predetermined part of a system comprising said distance measuring device in a known relationship to the first object, and

determining changes in position and orientation of the reflective object element relative to the predetermined part.

15. The use of the system according to claim 1 for positioning a first object in a known spatial position and orientation relative to a second object, comprising:

placing the reflective object element with observation mechanism in a known relationship to the second object,

positioning a predetermined part of a system comprising said distance measuring device in a known relationship to said first object,

determining changes in position and orientation of the objects relative to each other, corresponding to changes determined in position and orientation of the reflective object element relative to the predetermined part, and

enabling one object to be moved relative to the other in order to obtain a desired relative spatial position and orientation.

16. A probing tool according to claim 1.

20. A system for measurement of spatial coordinates according to claim 2, wherein said offset mechanism is connected with said reflective object element and with said observation mechanism via a mechanism constructed for relative rotation, said mechanism including a mechanism constructed and adapted to measure said rotation.

21. A system for measurement of spatial coordinates according to claim 2, wherein said offset mechanism and said observation mechanism are connected with the reflective object element via a gimbals arrangement for relative rotation, including a mechanism constructed and adapted to measure said rotation.

17. A method for measuring of spatial coordinates comprising:

a) directing a measuring beam from a distance measuring device to a reflective object element,

b) determining a direction of said measuring beam,

c) measuring a distance from said measuring device to said reflective object element,

d) observing at least two targets located in positions known relative to said distance measuring device by observation mechanism located in a known position and orientation relative to said reflective object element, and

e) determining the orientation of said reflective object element by observing said targets by said observation mechanism, using the direction of the measuring beam and the distance form the measuring device to the reflective object element.

18. A method according to claim 17 for measuring the relative spatial position and orientation of a first object and a second object, comprising:

positioning the reflective object element with observation mechanism in a known relationship to the second object,

positioning a predetermined part of a system comprising said distance measuring device in a known relationship to the first object,

determining changes in position and orientation for the first and second objects relative to each other by determining corresponding changes in position and orientation of the reflective object element relative to said predetermined part.

19. A method according to claim 17 for positioning a first object in a known spatial position and orientation relative to a second object, comprising:

(a) positioning the reflective object element with observation mechanism in a known relationship to the second object,

(b) positioning a predetermined part of a system comprising said distance measuring device in a known relationship to said first object,

(c) determining changes in position and orientation for the first and second objects relative to each other by determining corresponding changes in position and orientation of the reflective object element relative to said predetermined part, and

(d) enabling one object to be moved relative to the other in order to obtain a desired relative spatial position and orientation.