MULTI-AXIS CALIBRATION BLOCK

• US 20160223325A1
• Filed: 02/01/2016
• Published: 08/04/2016
• Est. Priority Date: 02/02/2015
• Status: Active Grant

• Current Assignee: Rolls-Royce North American Technologies, Inc. (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce North American Technologies, Inc. (Rolls-Royce Holdings Plc)
• Inventors: Gatton, Geoffrey L.
• Granted Patent: US 9,952,044 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01B 21/042 Calibration or calibration artifacts G01B3/30, G01B9/02072 take precedence
• CPC Class Codes: G01B 3/30 Bars, blocks, or strips in which the distance between a pair of faces is fixed, although it may be preadjustable, e.g. end measure, feeler strip

Abstract

A calibration block for calibrating a touch probe includes a calibration block body forming a bored hole providing a concave measurement surface, and a three dimensional object protruding from the calibration block body and providing a convex measurement surface, wherein the convex measurement surface provides opposing measurement contact points in at least two dimensions.

Claims

1. A system comprising:

a calibration block for calibrating a touch probe, the calibration block comprising;

a calibration block body forming a bored hole providing a concave measurement surface; and

a three dimensional object protruding from the calibration block body and providing a convex measurement surface, wherein the convex measurement surface provides opposing measurement contact points in at least two dimensions.

2. The system of claim 1, further comprising a magnetic base configured to secure the calibration block to a measurement table associated with a mechanical holding arm and the touch probe.

3. The system of claim 1,

wherein the bored hole at least approximates a cylindrical shape, and

wherein the concave measurement surface at least approximates a ring shape.

4. The system of claim 1, wherein the three dimensional object at least approximates a sphere.

5. The system of claim 1, further comprising a mounting rod protuding from the calibration block body, wherein the three dimensional object is mounted to the mounting rod.

6. The system of claim 1, wherein the convex measurement surface provides opposing measurement contact points in three dimensions to faciltate five-axis calibration of the touch probe.

7. The system of claim 1, further comprising:

a measurement table;

a five-axis mechanical holding arm configured to manipulate a touch probe to measure the calibration block and a component; and

a computing device, wherein the computing device is configured to;

send control signals to the five-axis mechanical holding arm to locate the touch probe mounted in the five-axis mechanical holding arm relative to the calibration block;

send control signals to the five-axis mechanical holding arm to measure the three dimensional object with a distal tip of the touch probe by contacting multiple points of the three dimensional object;

send control signals to the five-axis mechanical holding arm to measure the bored hole with sides of the distal tip of the touch probe by contacting multiple points of the concave measurement surface;

generate calibration factors for the touch probe by comparing the sizes of the three dimensional object and the bored hole as measured by manipluating the touch probe with the five-axis mechanical holding arm with predefined actual sizes of the three dimensional object and the bored hole; and

store the calibration factors for the touch probe in a non-tansitory computer readable medium.

8. The system of claim 7, further comprising a user interface configured to receive a user input indicating the predefined actual sizes.

9. The system of claim 7, the computing device is further configured to:

after storing the calibration factors for the touch probe, send control signals to the five-axis mechanical holding arm to measure features of the component with the distal tip of the touch probe, wherein the calibration block and the component are both secured to the measurement table during the measurement of the calibration block and the measurement of the component;

store values of the measured features of the component in the non-tansitory computer readable medium, the values being based on the calibration factors;

after storing values of the measured features of the component in the non-tansitory computer readable medium, send control signals to the five-axis mechanical holding arm to again measure at least one of the three dimensional object and the bored hole with the touch probe;

compare the sizes of the three dimensional object and the bored hole as measured by manipluating the touch probe with the five-axis mechanical holding arm with the predefined actual sizes of the three dimensional object and the bored hole to generate updated calibration factors for the touch probe; and

in the event that the updated calibration factors are substantially different than the calibration factors, update the stored values of the measured features of the component in the non-tansitory computer readable medium based on the updated calibration factors.

10. A method of calibrating a touch probe comprising:

locating a touch probe relative to a calibration block, the calibration block including a calibration block body forming a bored hole providing a concave measurement surface, and a three dimensional object protruding from the calibration block body and providing a convex measurement surface, wherein the convex measurement surface provides opposing measurement contact points in at least two dimensions;

measuring the three dimensional object with a distal tip of the touch probe by manipluating the touch probe with a five-axis mechanical holding arm and contacting multiple points of the three dimensional object;

measuring the bored hole with sides of the distal tip of the touch probe by manipluating the touch probe with a five-axis mechanical holding arm and contacting multiple points of the concave measurement surface;

comparing the sizes of the three dimensional object and the bored hole as measured by manipluating the touch probe with the five-axis mechanical holding arm with predefined actual sizes of the three dimensional object and the bored hole to generate calibration factors for the touch probe; and

storing the calibration factors for the touch probe in a non-tansitory computer readable medium.

11. The method of claim 10, wherein measuring the three dimensional object with the distal tip of the touch probe comprises and contacting at least six points of the three dimensional object.

12. The method of claim 11, wherein each point of the six points of the three dimensional object is at a different angular position about the three dimensional object.

13. The method of claim 10, further comprising mounting the touch probe in the five-axis mechanical holding arm.

14. The method of claim 10, further comprising:

after storing the calibration factors for the touch probe, measuring features of the component with the distal tip of the touch probe by manipluating the touch probe with the five-axis mechanical holding arm, wherein the calibration block and the component are both secured to the measurement table during the measurement of the calibration block and the measurement of the component;

storing values of the measured features of the component in the non-tansitory computer readable medium, the values being based on the calibration factors;

after storing values of the measured features of the component in the non-tansitory computer readable medium, again measuring at least one of the three dimensional object and the bored hole with the touch probe by manipluating the touch probe with the five-axis mechanical holding arm;

comparing the sizes of the three dimensional object and the bored hole as measured by manipluating the touch probe with the five-axis mechanical holding arm with the predefined actual sizes of the three dimensional object and the bored hole to generate updated calibration factors for the touch probe;

storing the updated calibration factors for the touch probe in the non-tansitory computer readable medium; and

in the event that the updated calibration factors are substantially different than the calibration factors, updating the stored values of the measured features of the component in the non-tansitory computer readable medium based on the updated calibration factors.

15. The method of claim 10,

wherein the bored hole at least approximates a cylindrical shape, and

wherein the concave measurement surface at least approximates a ring shape.

16. The method of claim 10, wherein the three dimensional object at least approximates a sphere.

17. A non-transitory computer-readable data storage medium having instructions stored thereon that, when executed by one or more processors of a computing device, cause the computing device to:

send control signals to a five-axis mechanical holding arm to locate a touch probe mounted in the five-axis mechanical holding arm relative to a calibration block, wherein the calibration block includes a calibration block body forming a bored hole providing a concave measurement surface, and a three dimensional object protruding from the calibration block body and providing a convex measurement surface, wherein the convex measurement surface provides opposing measurement contact points in at least two dimensions;

send control signals to the five-axis mechanical holding arm to measure the three dimensional object with a distal tip of the touch probe by contacting multiple points of the three dimensional object;

send control signals to the five-axis mechanical holding arm to measure the bored hole with sides of the distal tip of the touch probe by contacting multiple points of the concave measurement surface;

generate calibration factors for the touch probe by comparing the sizes of the three dimensional object and the bored hole as measured by manipluating the touch probe with the five-axis mechanical holding arm with predefined actual sizes of the three dimensional object and the bored hole; and

store the calibration factors for the touch probe in a non-tansitory computer readable medium.

18. The computer-readable data storage medium of claim 17, wherein the instructions stored on the computer-readable data storage medium, when executed by one or more processors of a computing device, further cause the computing device to:

after storing the calibration factors for the touch probe, send control signals to the five-axis mechanical holding arm to measure features of the component with the distal tip of the touch probe, wherein the calibration block and the component are both secured to the measurement table during the measurement of the calibration block and the measurement of the component;

store values of the measured features of the component in the non-tansitory computer readable medium, the values being based on the calibration factors;

after storing values of the measured features of the component in the non-tansitory computer readable medium, send control signals to the five-axis mechanical holding arm to again measure at least one of the three dimensional object and the bored hole with the touch probe;

compare the sizes of the three dimensional object and the bored hole as measured by manipluating the touch probe with the five-axis mechanical holding arm with the predefined actual sizes of the three dimensional object and the bored hole to generate updated calibration factors for the touch probe; and

in the event that the updated calibration factors are substantially different than the calibration factors, update the stored values of the measured features of the component in the non-tansitory computer readable medium based on the updated calibration factors.

19. The computer-readable data storage medium of claim 17,

wherein the bored hole at least approximates a cylindrical shape, and

wherein the concave measurement surface at least approximates a ring shape.

20. The computer-readable data storage medium of claim 17, wherein the three dimensional object at least approximates a sphere.