COORDINATE MEASURING SYSTEM

• US 20200132450A1
• Filed: 10/31/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Carl Zeiss Industrielle Messtechnik GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss Industrielle Messtechnik GmbH (Carl-Zeiss-Stiftung)
• Inventors: Grzesiak, Andrzej, Goller, Heiko, Mayer, Thomas
• Granted Patent: US 11,454,498 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/2545 with one projection direction and several detection directions, e.g. stereo
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01B 21/04 by measuring coordinates of points
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G05B 2219/37193 Multicoordinate measuring system, machine, cmm
• CPC Class Codes: G06T 2207/10152 Varying illumination
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes

Abstract

A coordinate measuring system includes a scanning module having a laser line scanner and a projection device. The laser line scanner projects a laser line onto a surface of a workpiece and produces scan data from a reflection of the laser line. The projection device and/or the laser line scanner project three optical markers onto the surface of the workpiece, at least one of the three markers being disposed on the laser line and at least one of the three markers being at a distance from the laser line. The coordinate measuring system includes an optical sensor capturing image data of the three optical markers and an evaluation device determining a position and an orientation of the coordinate system of the laser line scanner in the coordinate system of the optical sensor based on the image data of the optical sensor and the scan data of the laser line scanner.

Claims

1. A coordinate measuring system comprising:

a scanning module including a laser line scanner and a projection device, and defining a first coordinate system being body-fixed with respect to the scanning module,

the laser line scanner being configured to project a laser line onto a surface of a workpiece and to produce scan data from a reflection of the laser line being reflected from the surface of the workpiece,

the projection device being configured to project a first optical marker, at a distance from the laser line, onto the surface of the workpiece,

the first optical marker being disposed along a first direction predefined in the first coordinate system,

the projection device or the laser line scanner being configured to;

project a second optical marker onto the laser line, the second optical marker being disposed along a second direction predefined in the first coordinate system,

project a third optical marker onto the surface of the workpiece, the third optical marker being disposed along a third direction predefined in the first coordinate system;

an optical sensor defining a second coordinate system body-fixed with respect to the optical sensor and being configured to capture image data of the first optical marker, the second optical marker, and the third optical marker; and

an evaluation device configured to determine;

a first position of the first optical marker, a second position of the second optical marker, and a third position of the third optical marker in a second coordinate system based on the image data,

a fourth position of the second optical marker in the first coordinate system based on the scan data, and

a position and orientation of the first coordinate system with respect to the second coordinate system based on the first to the fourth position and the first to third direction.

2. The coordinate measuring system as claimed in claim 1, wherein:

the projection device or the laser line scanner is further configured to project the third optical marker onto the laser line,

the evaluation device is configured to determine;

a fifth position of the third optical marker in the first coordinate system based on the scan data,

a sixth position of the first optical marker in the first coordinate system based on the first to the third position, a fourth and/or fifth position, and the first to the third direction, and

the position and the orientation of the first coordinate system with respect to the second coordinate system based on the fourth to the sixth position.

3. The coordinate measuring system as claimed in claim 1, wherein:

the projection device is further configured to project the third optical marker onto the surface of the workpiece at the distance from the laser line,

the evaluation device is configured to determine;

a fifth position of the third optical marker in the first coordinate system and a sixth position of the first optical marker in the first coordinate system based on the first to the fourth position and the first to the third direction, and

the position and the orientation of the first coordinate system with respect to the second coordinate system based on the fourth to the sixth position.

4. The coordinate measuring system as claimed in claim 2, wherein the evaluation device is configured to determine:

a first distance between the first and the second optical marker and a second distance between the first and the third optical marker based on the first to the third position, and

two first points of intersection with a first direction based on the first distance, one of the two first points of intersection corresponding to the sixth position of the first optical marker in the first coordinate system, or

two second points of intersection with the first direction based on the second distance, one of the two second points of intersection corresponding to the sixth position of the first optical marker in the first coordinate system.

5. The coordinate measuring system as claimed in claim 4, wherein the evaluation device is further configured to determine:

the two first points of intersection by solving an intersection equation of a first enveloping sphere with a straight line along the first direction, the first enveloping sphere being defined by the fourth position as a sphere center and the first distance as a first radius, or

the two second points of intersection by solving the intersection equation of a second enveloping sphere with the straight line along the first direction, the second enveloping sphere being defined by the fifth position as the sphere center and the second distance as a second radius.

6. The coordinate measuring system as claimed in claim 3, wherein the evaluation device is configured to determine:

a first distance between the first and the second optical marker and a third distance between the second and the third optical marker based on the first to the third position,

two first points of intersection with a first direction based on the first distance, one of the two first points of intersection corresponding to the sixth position of the first optical marker in the first coordinate system, and

two third points of intersection with the third direction based on the third distance, one of the two third points of intersection corresponding to the fifth position of the third optical marker in the first coordinate system.

7. The coordinate measuring system as claimed in claim 6, wherein the evaluation device is further configured to determine:

the two first points of intersection by solving an intersection equation of a first enveloping sphere with a straight line along the first direction, the first enveloping sphere being defined by the fourth position as a sphere center and the first distance as a first radius, and

the two third points of intersection by solving the intersection equation of a third enveloping sphere with the straight line along the third direction, the third enveloping sphere being defined by the fourth position as the sphere center and the third distance as a third radius.

8. The coordinate measuring system as claimed in claim 4, wherein the evaluation device is configured to determine the fifth position from the two first points of intersection and/or the sixth position from the two second points of intersection or from two third points of intersection by including a coordinate measuring history.

9. The coordinate measuring system as claimed in claim 4, wherein the evaluation device is configured to determine the fifth position from the two first points of intersection and/or the sixth position from the two second points of intersection or from two third points of intersection by including predefined geometric relationships of a coordinate measuring structure of the coordinate measuring system.

10. The coordinate measuring system as claimed in claim 1, wherein:

the laser line scanner is configured to produce the laser line between two endpoints, and

the second optical marker is disposed on a first one of the two endpoints.

11. The coordinate measuring system as claimed in claim 10, wherein:

the third optical marker is disposed on a second one of the two endpoints,

the projection device or the laser line scanner is further configured to project the third optical marker onto the laser line,

the evaluation device is configured to determine;

a fifth position of the third optical marker in the first coordinate system based on the scan data,

a sixth position of the first optical marker in the first coordinate system based on the first to the third position and a fourth and/or fifth position and the first to the third direction, and

the position and the orientation of the first coordinate system with respect to the second coordinate system based on the fourth to the sixth position, the third optical marker being disposed on a second of the two endpoints.

12. The coordinate measuring system as claimed in claim 1, wherein each of the first to the third direction extends obliquely with respect to one another, proceeding from a common origin defined by the first coordinate system.

13. The coordinate measuring system as claimed in claim 12, wherein the first to the third direction include angles of inclination a of a same magnitude among one another.

14. A coordinate measuring method comprising:

producing a laser line onto a surface of a workpiece;

projecting a first optical marker onto the surface of the workpiece, the first optical marker being at a distance from the laser line, and disposed along a first direction predefined in a first body-fixed coordinate system;

projecting a second optical marker onto the laser line, the second optical marker being disposed along a second direction predefined in the first coordinate system;

projecting a third optical marker onto the surface of the workpiece, the third optical marker being disposed along a third direction predefined in the first coordinate system;

determining a first position of the first optical marker, a second position of the second optical marker, and a third position of the third optical marker in a second body-fixed coordinate system;

determining a fourth position of the second optical marker in the first body-fixed coordinate system; and

determining a position and orientation of the first coordinate system with respect to a second coordinate system based on the first to the fourth position and the first to third direction.

15. The coordinate measuring method as claimed in claim 14, further comprising:

projecting the third optical marker onto the laser line;

determining a fifth position of the third optical marker in the first coordinate system;

determining a sixth position of the first optical marker in the first coordinate system based on the first to the third position and a fourth and/or fifth position and the first to the third direction; and

determining the position and the orientation of the first coordinate system with respect to the second coordinate system based on the fourth to the sixth position.

16. The coordinate measuring method as claimed in claim 14, further comprising:

projecting the third optical marker onto the surface of the workpiece at the distance from the laser line;

determining a fifth position of the third optical marker in the first coordinate system and a sixth position of the first optical marker in the first coordinate system based on the first to the fourth position and the first to the third direction; and

determining the position and the orientation of the first coordinate system with respect to the second coordinate system based on the fourth to the sixth position.

17. The coordinate measuring method as claimed in claim 16, further comprising:

determining, based on the first to the third position, a first distance between the first optical marker and the second optical marker and a second distance between the first optical marker and the third optical marker, and

determining two first points of intersection with a first direction based on the first distance, one of the two first points of intersection corresponding to the sixth position of the first optical marker in the first coordinate system, or

determining two second points of intersection with the first direction based on the second distance, one of the two second points of intersection corresponding to the sixth position of the first optical marker in the first coordinate system.

18. The coordinate measuring method as claimed in claim 17 further comprising:

determining the two first points of intersection by solving an intersection equation of a first enveloping sphere with a straight line along the first direction, the first enveloping sphere being defined by the fourth position as a sphere center and the first distance as a first radius, or

determining the two second points of intersection by solving the intersection equation of a second enveloping sphere with the straight line along the first direction, the second enveloping sphere being defined by way of the fifth position as the sphere center and the second distance as a second radius.

19. The coordinate measuring method as claimed in claim 17, further comprising:

determining, based on the first to the third position, the first distance between the first optical marker and the second optical marker and a third distance between the second optical marker and the third optical marker;

determining the two first points of intersection with the first direction based on the first distance, one of the two first points of intersection corresponding to the sixth position of the first optical marker in the first coordinate system; and

determining two third points of intersection with the third direction based on the third distance, one of the two third points of intersection corresponding to the fifth position of the third optical marker in the first coordinate system.

20. A coordinate measuring system comprising:

a scanner configured to;

produce a laser line onto a surface of a workpiece,

project a first optical marker onto the surface of the workpiece, the first optical marker being at a distance from the laser line and disposed along a first direction predefined in a first body-fixed coordinate system,

project a second optical marker onto the laser line, the second optical marker being disposed along a second direction predefined in the first coordinate system, and

project a third optical marker onto the surface of the workpiece, the third optical marker being disposed along a third direction predefined in the first coordinate system; and

a computation device comprising an electronic circuitry configured to determine;

a first position of the first optical marker, a second position of the second optical marker, and a third position of the third optical marker in a second body-fixed coordinate system,

a fourth position of the second optical marker in the first body-fixed coordinate system, and

a position and orientation of the first coordinate system with respect to a second coordinate system based on the first to the fourth position and the first to third direction.