Dynamically Adapting Operation of a Coordinate Measuring Machine

• US 20190316893A1
• Filed: 04/16/2018
• Published: 10/17/2019
• Est. Priority Date: 04/16/2018
• Status: Active Grant

• Current Assignee: Hexagon Metrology Incorporated (Hexagon AB)
• Original Assignee: Hexagon Metrology Incorporated (Hexagon AB)
• Inventors: Singh, Gurpreet, Schneider, Jurgen
• Granted Patent: US 11,231,262 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 21/04 by measuring coordinates of points
• CPC Class Codes: G01B 21/045 Correction of measurements G01B9/02055 takes precedence
• CPC Class Codes: G01B 21/047 Accessories, e.g. for positioning, for tool-setting, for measuring probes
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G01B 5/20 for measuring contours or curvatures
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37218 Compensate for offset due to probe diameter, detect exact contact point
• CPC Class Codes: G05B 2219/37452 Generate nc program from metrology program, defining cmm probe path

Abstract

A coordinate measuring machine revises its original measurement trajectory, prior to completing its measurement of a work piece, upon detecting misalignment between its original measurement trajectory and the orientation of the work piece.

Claims

1. A system for measuring a work piece, the system comprising:

a trajectory module configured to store an established measurement trajectory;

a controller in data communication with the trajectory module to receive, from the trajectory module, the established measurement trajectory, and configured to control a measuring probe according to a subset of, but less than all of, the established measurement trajectory;

a trajectory analysis module configured to analyze an actual trajectory executed by the measuring probe, relative to the established measurement trajectory, based on measurements of the work piece taken according to at least two consecutive target points of the established measurement trajectory, and to produce a trajectory divergence; and

a trajectory revision module configured to generate a revised trajectory based on the established measurement trajectory and the trajectory divergence,

the controller configured to control the measuring probe to measure the work piece according to the revised trajectory.

2. The system of claim 1, wherein:

the established measurement trajectory includes a plurality of target points, the plurality of target points having a fixed spatial relationship relative to one another; and

generating a revised trajectory includes retaining the fixed spatial relationship of the measurements relative to one another.

3. The system of claim 2, wherein:

the established measurement trajectory further includes a plurality of moves corresponding to the plurality of target points, each move defining a path, followed by the measuring probe, between consecutive target points.

4. The system of claim 2, wherein:

the established measurement trajectory further comprises a plurality of moves corresponding to the plurality of target points, each move defining a path, followed by the measuring probe, between consecutive target points, the plurality of moves having a fixed spatial relationship relative to one another; and

generating a revised trajectory includes retaining the fixed spatial relationship of the moves relative to one another.

5. The system of claim 1, wherein generating a revised trajectory includes shifting a subset of target points of the established measurement trajectory by linearly offsetting the subset of target points in space to match a linear offset of the work piece.

6. The system of claim 1, wherein generating a revised trajectory includes shifting a subset of target points of the established measurement trajectory by rotationally offsetting the subset of target points in space to match a rotational offset of the work piece.

7. The system of claim 1, wherein generating a revised trajectory includes both:

linearly offsetting each point of a subset of target points, and

rotationally offsetting each point of the subset of target points, to match both a linear offset and a rotational offset of the work piece.

8. A method of dynamically adapting the operation of a coordinate measuring machine while measuring a work piece, the method including:

providing, to the coordinate measuring machine, an established measurement trajectory comprising a plurality of pre-defined target points, each of the plurality of pre-defined target points having a coordinate location;

controlling the coordinate measuring machine to acquire a plurality of initial acquired measurements of the work piece according to an initial set of target points, the initial set of target points being a subset of the plurality of pre-defined target points, the initial set of pre-defined target points defining a remainder of target points;

storing the plurality of initial acquired measurements in a memory;

after controlling the coordinate measuring machine to acquire the plurality of initial acquired measurements, but prior to completing execution of the established measurement trajectory, establishing a trajectory divergence based on at least two of the plurality of initial acquired measurements;

based on the trajectory divergence, producing a re-oriented set of target points from the remainder of target points, the re-oriented set of target points configured to reduce the trajectory divergence;

controlling the coordinate measuring machine to continue measuring the work piece according to the re-oriented set of target points, thereby acquiring a remainder of measurements; and

storing the remainder of measurements in the memory.

9. The method of claim 8, wherein:

the pre-defined target points of the established measurement trajectory have a fixed spatial relationship relative to one another; and

producing a re-oriented set of target points comprises shifting the remainder of target points in space, but retaining the fixed spatial relationship of the remainder of target points relative to one another.

10. The method of claim 9, wherein:

the established measurement trajectory further includes a plurality of moves corresponding to the plurality of pre-defined target points, each move of the plurality of moves defining a path, followed by a probe of the coordinate measuring machine, between consecutive ones of the pre-defined target points.

11. The method of claim 9, wherein:

the established measurement trajectory further comprises a plurality of moves corresponding to the plurality of pre-defined target points, each move defining a path, followed by a probe of the coordinate measuring machine, between consecutive ones of the pre-defined target points, the plurality of moves having a fixed spatial relationship relative to one another; and

producing a re-oriented set of target points comprises shifting the remainder of target points in space, but retaining the fixed spatial relationship of the moves relative to one another.

12. The method of claim 9, wherein shifting the remainder of target points in space comprises linearly offsetting each of the remainder of target points in space to match a linear offset of the work piece.

13. The method of claim 9, wherein shifting the remainder of target points in space comprises rotationally offsetting the remainder of target points in space to match a rotational offset of the work piece.

14. The method of claim 9, wherein shifting the remainder of target points in space comprises both:

linearly offsetting the remainder of target points in space, and

rotationally offsetting the remainder of target points in space, to match both a linear offset and a rotational offset of the work piece.

15. A non-transient computer program product bearing non-transient executable computer code which, when executed by a computer processor, control a coordinate measuring machine, the executable computer code comprising:

code for causing a controller to measure a work piece according to each of two target points of an established measurement trajectory, each of the two target points having a pre-established coordinate location according to the established measurement trajectory, to produce two corresponding location measurements, the two target points defining a remainder of target points of the established measurement trajectory;

code for assessing, prior to completing execution of the established measurement trajectory, an orientation of the work piece by processing the two location measurements relative to the pre-established coordinate locations

code for producing a re-oriented set of target points from the remainder of target points of the established measurement trajectory; and

code for controlling the coordinate measuring machine to continue measuring the work piece by measuring the work piece according to the re-oriented set of target points.

16. The non-transient computer program product of claim 15, wherein:

the established measurement trajectory includes a plurality of target points, the plurality of target points having a fixed spatial relationship relative to one another; and

code for producing a re-oriented set of target points comprises code for shifting the remainder of target points in space, but retaining the fixed spatial relationship of the remainder of target points relative to one another.

17. The non-transient computer program product of claim 16, wherein:

the established measurement trajectory further includes a plurality of moves corresponding to the plurality of target points, each move defining a path, followed by a probe of the coordinate measuring machine, between consecutive target points.

18. The non-transient computer program product of claim 16, wherein:

the established measurement trajectory further comprises a plurality of moves corresponding to the plurality of target points, each move defining a path, followed by a probe of the coordinate measuring machine, between consecutive target points, the plurality of moves having a fixed spatial relationship relative to one another; and

code for producing a re-oriented set of target points comprises code for shifting the remainder of target points in space, but retaining the fixed spatial relationship of the remainder of target points relative to one another.

19. The non-transient computer program product of claim 18, wherein code for shifting the remainder of target points in space comprises code for linearly offsetting the remainder of target points in space to match a linear offset of the work piece.

20. The non-transient computer program product of claim 18, wherein code for shifting the remainder of target points in space comprises code for rotationally offsetting the remainder of target points in space to match a rotational offset of the work piece.