Measurement of spatial coordinates

• US 20040160594A1
• Filed: 02/11/2004
• Published: 08/19/2004
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Metroner ASA
• Original Assignee: Metronor ASA
• Inventors: Rotvold, Oyvind, Amdal, Knut, Suphellen, Harald
• Granted Patent: US 7,145,647 B2
• Time in Patent Office: Days
• US Class Current: 356/4.01
• 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 comprising a probing tool and a main measuring unit (18), wherein said probing tool comprises

a) a reflective object element (26),

b) observation mechanism (24) located in a known position and orientation relative to said reflective object element (26) and capable of observing targets (36, 36′

); and

wherein said main measuring unit comprises

c) a distance measuring device (10) capable of measuring a distance from said device (10) to said reflective object element (26);

d) a mechanism (14) constructed and adapted to direct a measuring beam from said distance measuring device (10) to said reflective object element (26);

e) a direction determining mechanism (16) constructed and adapted to determine a direction of a measuring beam;

f) at least two targets (36, 36′

) located in known positions relative to said distance measuring device (10), whereby the orientation of said reflective object element (26) can be determined from observations of said targets (36, 36′

) by said observation mechanism (24);

2. A system for the measurement of spatial coordinates according to claim 1, wherein said reflective object element (26) is associated with [is connected to] an offset mechanism (28, 32) for measuring points other than the center of said reflective object element (26) by using a known orientation and position of said reflective object element (26).

3. A system for the measurement of spatial coordinates according to claim 2, wherein said offset mechanism (28, 32) is a mechanical probe or stylus constructed and adapted to be held in contact with points to be measured.

4. A system for measurement of spatial coordinates according to any of claims 2 to 3, wherein said offset mechanism (28, 32) is connected with said reflective object element (26) and with said observation mechanism (24) via a mechanism (34) constructed for relative rotation, said mechanism including a means for measuring said rotation.

5. A system for measurement of spatial coordinates according to any of claims 2 to 3, wherein said offset mechanism (28, 32) and said observation mechanism (24) are connected with the reflective object element (26) via a gimbals arrangement (34) for relative rotation, including a means for measuring said rotation.

6. A system for measurement of spatial coordinates according to any of claims 1 to 5, wherein said observation mechanism (24) 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 targets.

7. A system for the measurement of spatial coordinates according to any of claims 2 to 6, wherein said offset mechanism (28, 32) is a device for measuring distance and direction relative to said reflective object element (26).

8. A system for the measurement of spatial coordinates according to any of claims 2 to 5, wherein said offset mechanism (28, 32) is a surface scanning system or similar device for simultaneously measuring a plurality of points relative to said reflective object element (26).

9. A system for the measurement of spatial coordinates according to any of claims 1 to 8, wherein said observation mechanism (24) is one or more cameras.

10. A system for the measurement of spatial coordinates according to any of claims 1 to 8, wherein said observation mechanism (24) is one or more one-dimensional linear array cameras.

11. A system for measurement of spatial coordinates according to any of claims 1 to 10, wherein said targets (36, 36′

, . . .) are selected from the group of passive targets including but not limited to simple measurement marks, cross-hairs;

retro-reflective targets;

coded retro-reflective targets.

12. A system for measurement of spatial coordinates according to any of claims 1 to 10, wherein said targets (36, 36′

, . . .) are active light-emitting targets including but not limited to light-emitting diodes (LEDs).

13. A system for measurement of spatial coordinates according to any of claims 1 to 10, wherein said targets (36, 36′

, . . .) are represented by predetermined features or shape elements comprising said features inherent in known objects or classes of objects.

14. A system for measurement of spatial coordinates according to any of claims 1 to 13, wherein said distance measuring device (10) is part of a laser tracker.

15. A system according to claim 1 for measuring the relative spatial position and orientation of an object, wherein the reflective object element (26) with observation mechanism (24) 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 (26) correspond to the changes in position and orientation for the object.

16. A system according to claim 1 for measuring the relative spatial position and orientation of a first object and a second object, wherein

the reflective object element (26) with observation mechanism (24) is placed in a known relationship to the second object,

a predetermined part of a system comprising said distance measuring device (10) is positioned in a known relationship to the first object so that changes determined in position and orientation of the reflective object element (26) relative to the predetermined part correspond to changes in position and orientation of the objects relative to each other.

17. A system according to claim 1 for positioning a first object in a known spatial position and orientation relative to a second object, wherein

the reflective object element (26) with observation mechanism (24) is placed in a known relationship to the second object,

a predetermined part of a system comprising said distance measuring device (10) is positioned in a known relationship to said first object,

so that changes determined in position and orientation of the reflective object element (26) relative to the predetermined part correspond to changes in position and orientation of the objects relative to each other, thus enabling one object to be moved relative to the other in order to obtain a desired relative spatial position and orientation.

18. A probing tool according to any of the preceding claims.

19. A method for measuring of spatial coordinates comprising:

a) directing a measuring beam from a distance measuring device (10) to a reflective object element (26),

b) determining a direction of said measuring beam,

c) measuring a distance from said measuring device (10) to said reflective object element (26),

d) observing at least two targets (36, 36′

, . . .) located in positions known relative to said distance measuring device (10) by observation mechanism (24) located in a known position and orientation relative to said reflective object element (26), and

e) determining the orientation of said reflective object element (26) by observing said targets (36, 36′

, . . .) by said observation mechanism (24).

20. A method according to claim 19 for measuring the relative spatial position and orientation of a first object and a second object, comprising:

positioning the reflective object element (26) with observation mechanism (24) in a known relationship to the second object, positioning a predetermined part of a system comprising said distance measuring device (10) 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 (26) relative to said predetermined part.

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

(a) positioning the reflective object element (26) with observation mechanism (24) in a known relationship to the second object,

(b) positioning a predetermined part of a system comprising said distance measuring device (10) 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 (26) relative to said predetermined part,

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