Coordinate Measuring Probe Elasticity Compensation
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Solution Overview
Problem
Existing coordinate measuring machines face accuracy issues when determining the coordinates of a workpiece due to the neglect of the elastic properties of the probe, particularly when the measuring force does not pass through the center of the probe ball, leading to significant errors, especially with non-isotropic stylus flexibility.
Innovation Solution
The method involves accounting for the elastic properties of the probe during calibration and operation by using compliance matrices to determine the directional dependency of the probe's flexibility, allowing for precise control of the probing force and direction, and adjusting the flexibility ellipsoid to minimize slipping during measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the elastic properties of the probe are neglected to simplify the measurement process, then the device complexity is reduced, but the measurement precision deteriorates due to significant errors when the measuring force does not pass through the center of the probe ball
Solution Approach 1:
The compliance matrix is determined in advance during calibration before actual measurement. This preliminary determination of elastic properties allows the system to compensate for probe deflection during measurement without adding complexity to the measurement process itself
Solution Approach 2:
The system transforms physical elastic properties into a mathematical compliance matrix that characterizes the probe's flexibility. By changing the representation of elastic properties from physical parameters to mathematical parameters, the system can accurately model probe behavior without increasing measurement complexity
2Productivity
If the probe's flexibility is not considered to reduce calculation overhead, then the productivity is improved, but the manufacturing precision deteriorates due to errors in coordinate determination
Solution Approach 1:
The compliance matrix is pre-determined during calibration, so that during actual measurement, the system can directly apply this matrix to compensate for elastic deflection without performing complex real-time calculations, thus maintaining both speed and accuracy
3Ease of operation
If the measuring force is applied without considering directional dependency to simplify operation, then the ease of operation is improved, but the measurement precision deteriorates due to non-isotropic stylus flexibility
Solution Approach 1:
The system automatically determines the optimal probing direction based on the compliance matrix without requiring manual intervention. The operator simply needs to position the probe near the measurement point, and the system self-adjusts the approach direction to account for anisotropic flexibility, maintaining both ease of operation and measurement precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of coordinate determination by considering the probe's elastic properties, reducing errors and maintaining contact with the workpiece surface, even when the measuring force does not pass through the probe's center, thereby improving measurement precision and reliability.
Implementation Method 1
the stylus is deflected relative to a mounting of the probe head when probing the surface
Data Source
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AI summary
The invention relates to measuring a work piece (52), wherein at least one point (53) of a surface of the work piece (52) is sampled by a feeler (11), wherein the feeler (11) exerts a probing force (f') on the surface (51) and the feeler (11) is deflected relative to a mounting of the feeler (11). On the basis of the deflection (vector a), a position of the point (53) of the surface is determined. A directional dependence of a flexibility of the feeler (11) is determined and/or is known. The feeler (11) and the work piece (52) are positioned and/or oriented relative to each other, while taking into consideration the directional dependence, such that during sampling of the point (53) of the surface (51) unintentional slipping of the feeler (11) on the surface (51) does not occur, or occurs only with low probability, or an unintentional deviation of the feeler (11) from an intended path on the surface (51) does not occur, or occurs only with low probability.