Patent EP0275428A2 successfully refreshed from Google Patents.
EP0275428A2
Expired / Lapsed
EP
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Method for calibrating a coordinate measuring machine and the like
Assignee: Warner and Swasey Co
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Filing: 1987-12-01
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Granted: —
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Expires: 2007-12-01
Abstract
Abstract Method (FIGURES 4A through 4C) and system (FIGURE 3) are disclosed for automatically calibrating a coordinate measuring machine (CMM) (10). The system guides an operator through instrument set-up and data collection procedures. The system automatically converts the collected data into error compensation or axis correction data which represents 21 different geometry errors (i.e. pitch, yaw, roll etc.) of the CMM (10). The error compensation data is then transferred to a CMM measurement processor (36) for subsequent use by the CMM (10) during operation thereof to thereby compensate the CMM (10) for its entire measuring volume (102).
Inventors
- 👤 Frederick K. Bell
- 👤 Stephen N. Brown
- 👤 Gary E. Brazier
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 22:57
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/004; G01B7/008; G01B21/00; G01B21/02; G01B21/04; G01B21/045
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
250 words
A method for calibrating a CMM (10) having a measuring volume (102), the CMM including a probe shaft (22) having three axes of motion (X, Y and Z), a probe supported on the distal end of the probe shaft, devices for providing position signals in determining the position of the probe for each of the axes of motion in the coordinate frame of the CMM and control means (36) for receiving the position signals and for providing a coordinate measurement signal which identifies the position of the probe, the method including the steps of: moving (FIGURES 4A through 4C) the CMM from a first predetermined position to a plurality of other predetermined positions along the length of each of the axes of motion so as to generate position signals in the coordinate frame of the CMM; measuring (FIGURES 4A through 4C) the position of the CMM in a standard coordinate frame having a standard axis system at each of the predetermined positions to obtain measured calibration data; and processing (FIGURES 4A through 4C) the position signals and the calibration data, and wherein the method is characterized by: said step of processing including the step of correlating (FIGURES 4A through 4C) the position signals and the calibration data to obtain axis correction data for each of said predetermined positions; and storing (108) the axis correction data in a form which can be utilized by the control means during operation of the CMM to compensate the CMM for the entire measuring volume.
Claim 2
Independent Claim
250 words
A method for calibrating a CMM (10) having a measuring volume (102), the CMM including a probe shaft (22) having three axes of motion (X, Y and Z), a probe supported on the distal end of the probe shaft, devices for providing position signals in determining the position of the probe for each of the axes of motion in the coordinate frame of the CMM and control means (36) for receiving the position signals and for providing a coordinate measurement signal which identifies the position of the probe, the method including the steps of: moving (FIGURES 4A through 4C) the CMM from a first predetermined position to a plurality of other predetermined positions along the length of each of the axes of motion so as to generate position signals in the coordinate frame of the CMM; measuring (FIGURES 4A through 4C) the position of the CMM in a standard coordinate frame having a standard axis system at each of the predetermined positions to obtain measured calibration data; and processing (FIGURES 4A through 4C) the position signals and the calibration data, and wherein the method is characterized by: said step of processing including the step of correlating (FIGURES 4A through 4C) the position signals and the calibration data to obtain axis correction data for each of said predetermined positions; and storing (108) the axis correction data in a form which can be utilized by the control means during operation of the CMM to compensate the CMM for the entire measuring volume.
Claim 3
Independent Claim
226 words
A system (FIGURE 3) for calibrating a CMM (10) having a measuring volume, the CMM including a probe shaft (22) having three axes of motion (X, Y, Z), a probe supported on the distal end of the probe shaft, devices for providing a position signal in determining the position of the probe for each of the axes of motion in the coordinate frame of the CMM and control means (36) for receiving the position signals and for providing a coordinate measurement signal which identifies the position of the probe, the system comprising at least one calibration device (32) for measuring the position of the CMM in a standard coordinate frame having a standard axis system at a plurality of predetermined positions of the CMM to obtain measured calibration data, the devices generating the position signals in the coordinate frame of the CMM; and data processing means (34) for processing the position signals and the calibration data, the system being characterized by the data processing means including means (FIGURES 4A through 4C) for correlating the position signals and the calibration data to obtain axis correction data for each of said predetermined positions; and storage means (110) for storing the axis correction data in a form which can be utilized by the control means during operation of the CMM to compensate the CMM for the entire measuring volume.
Claim 4
Independent Claim
226 words
A system (FIGURE 3) for calibrating a CMM (10) having a measuring volume, the CMM including a probe shaft (22) having three axes of motion (X, Y, Z), a probe supported on the distal end of the probe shaft, devices for providing a position signal in determining the position of the probe for each of the axes of motion in the coordinate frame of the CMM and control means (36) for receiving the position signals and for providing a coordinate measurement signal which identifies the position of the probe, the system comprising at least one calibration device (32) for measuring the position of the CMM in a standard coordinate frame having a standard axis system at a plurality of predetermined positions of the CMM to obtain measured calibration data, the devices generating the position signals in the coordinate frame of the CMM; and data processing means (34) for processing the position signals and the calibration data, the system being characterized by the data processing means including means (FIGURES 4A through 4C) for correlating the position signals and the calibration data to obtain axis correction data for each of said predetermined positions; and storage means (110) for storing the axis correction data in a form which can be utilized by the control means during operation of the CMM to compensate the CMM for the entire measuring volume.
Claim 5
Dependent Claim
83 words
The invention as claimed in claim 1 or claim 2 wherein said axis correction data include: nine sets of compensated rotation data (48 through 64) representing the amount of angular rotation about each of the axes for each of the axes; squareness data (84, 94, 96) representing the orthogonality of three different pairs of the axes; six sets of normalized straightness data (72 through 82) for said axes; and three sets of scale error data (66, 68, 70) representing errors in the devices.
Claim 6
Dependent Claim
26 words
The method as claimed in claim 1 wherein said step of processing further provides squareness data (84, 94 and 96) representing the orthogonality of the axes.
Claim 7
Dependent Claim
109 words
The method as claimed in claim 1 wherein the method is further characterized by the steps of: (a) installing (FIGURE 5A) an artifact on the CMM in a first position within a plane defined by a first pair of the axes of motion, the artifact having two ends separated by a distance; (b) moving (FIGURE 5A) the artifact to a second position within the plane; (c) moving (86) the probe so that the CMM generates coordinate data representing the positions defined by the ends of the artifact in each of the positions; and (d) repeating steps (a) through (c) for second and third pairs of the axes of motion.
Claim 8
Dependent Claim
56 words
The method as claimed in claim 5 wherein the artifact is a ball bar having first and second ends separated by a fixed distance and wherein step (c) is accomplished by coupling the probe to both ends of the ball bar so that the coordinate data represents positions defined by the ends of the ball bar.
Claim 9
Dependent Claim
32 words
The method as claimed in claim 5 or claim 6 wherein said step of processing includes the step of calculating (90) the squareness for each of the planes from the coordinate data.
Claim 10
Dependent Claim
56 words
The method as claimed in claim 5, 6 or 7, wherein the method is further characterized by the steps of: installing (FIGURE 7A) a second artifact on the CMM at a predetermined location within the measuring volume; and moving (86) the probe so that the CMM generates coordinate data representing the position of the second artifact.
Claim 11
Dependent Claim
36 words
The method as claimed in claim 8 wherein the second artifact comprises a calibration sphere (100) and wherein the step of moving is accomplished by coupling the probe to a plurality of positions on the sphere.
Claim 12
Dependent Claim
24 words
The method as claimed in claim 9 wherein said step of processing includes the step of calculating the calibration coordinates from the coordinate data.
References Cited (Backward Citations)
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