Multi-axis calibration block

• US 9,952,044 B2
• Filed: 02/01/2016
• Issued: 04/24/2018
• 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.
• Primary Examiner(s): Rogers, David A
• Application Number:
  US15/012,631
• Publication Number:
  US 20160223325A1
• Time in Patent Office: 813 Days
• 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 measurement table;

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;

a magnetic base comprising one or more permanent magnets and a manual release mechanism configured to facilitate releasing the magnetic base from the measurement table; 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;

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

a computing device 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 manipulating the touch probe with the five-axis mechanical holding arm with predefined actual sizes of the three dimensional object and the bored hole;

store the calibration factors for the touch probe in a non-transitory computer readable medium;

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-transitory computer readable medium, the values being based on the calibration factors;

after storing values of the measured features of the component in the non-transitory 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 at least one of the three dimensional object and the bored hole as measured by manipulating the touch probe with the five-axis mechanical holding arm with the predefined actual sizes of the at least one 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-transitory computer readable medium based on the updated calibration factors.

2. 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.

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

4. 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.

5. 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.

6. The system of claim 1, further comprising a user interface configured to receive a user input indicating the predefined actual sizes.

7. A method of calibrating a touch probe comprising:

securing a calibration block to a measurement table using one or more permanent magnets in a magnetic base of the calibration block, wherein the magnetic base further comprises a manual release mechanism configured to facilitate releasing the magnetic base from the measurement table;

locating the 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 manipulating 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 manipulating 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 manipulating 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;

storing the calibration factors for the touch probe in a non-transitory computer readable medium;

after storing the calibration factors for the touch probe, measuring features of the component with the distal tip of the touch probe by manipulating 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-transitory computer readable medium, the values being based on the calibration factors;

after storing values of the measured features of the component in the non-transitory computer readable medium, again measuring at least one of the three dimensional object and the bored hole with the touch probe by manipulating 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 manipulating 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-transitory 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-transitory computer readable medium based on the updated calibration factors.

8. The method of claim 7, 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.

9. The method of claim 8, wherein each point of the six points of the three dimensional object is at a different angular position about the three dimensional object.

10. The method of claim 7, further comprising mounting the touch probe in the five-axis mechanical holding arm.

11. The method of claim 7,

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

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

12. The method of claim 7, wherein the three dimensional object at least approximates a sphere.

13. 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,

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, and

a magnetic base comprising a magnetic base comprising one or more permanent magnets and a manual release mechanism configured to facilitate releasing the magnetic base from the measurement table;

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 manipulating the touch probe with the five-axis mechanical holding arm with predefined actual sizes of the three dimensional object and the bored hole;

store the calibration factors for the touch probe in a non-transitory computer readable medium;

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-transitory computer readable medium, the values being based on the calibration factors;

after storing values of the measured features of the component in the non-transitory 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 manipulating 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-transitory computer readable medium based on the updated calibration factors.

14. The computer-readable data storage medium of claim 13,

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

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

15. The computer-readable data storage medium of claim 13, wherein the three dimensional object at least approximates a sphere.