Coordinate Measuring Machine Non-Linear Probe Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional coordinate measuring machines fail to accurately correct non-linear errors in probe outputs, leading to inaccuracies in shape coordinate measurements due to non-linear responses from spring structures and probe sensors.
Innovation Solution
A coordinate measuring machine with a restraining unit that prevents translational displacement of the measurement tip, allowing for the acquisition of both linear and non-linear correction elements to generate a correction matrix, which corrects probe outputs by transforming them into the machine coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only first-order coordinate components are corrected using a correction matrix, then the correction process is simple, but non-linear errors in probe output cannot be eliminated
Solution Approach 1:
The patent extends the correction matrix from first-order (linear) coordinate components to include second-order and higher-order (non-linear) coordinate components. This parameter expansion allows the correction system to address non-linear errors while maintaining a systematic matrix-based approach, thus improving measurement precision without completely overwhelming complexity
Solution Approach 2:
The correction process is divided into distinct segments: acquiring probe output at multiple measurement points, calculating both linear and non-linear correction elements separately, and then combining them in a comprehensive correction matrix. This segmentation makes the complex non-linear correction process more manageable and systematic
2Measurement precision
If the measuring probe is moved to multiple measurement points for correction, then correction accuracy improves, but measurement time increases
Solution Approach 1:
The patent acquires probe output at a specific number of measurement points that is sufficient to calculate both linear and non-linear correction elements. Rather than using excessive measurement points that would unnecessarily extend time, the method uses the minimum required points to achieve accurate non-linear correction, balancing precision and efficiency
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A processing device(400) includes: a coordinate acquisition unit (406) that acquires a moving amount M of a measuring probe (300) and a probe output P when the measuring probe (300) is moved by a drive mechanism(220) while restraining a measurement tip(306) by restraining unit (240) ; a matrix generation unit (408) that generates a correction matrix AA including linear correction elements and non-linear correction elements for respectively correcting linear coordinate components and non-linear coordinate components of the probe output P with respect to the moving amount M of the measuring probe (300) on the basis of an output of the coordinate acquisition unit(406); and a probe output correction unit(410) that corrects the probe output P with the correction matrix AA. The coordinate acquisition unit(406) acquires the moving amount M and the probe output P of the measuring probe (300) in each of measurement points in a quantity larger than or equal to the sum of the number of the linear correction elements and the number of the non-linear correction elements. Consequently, a non-linear error of the probe output P supplied from the measuring probe (300) can be corrected, and thus shape coordinates X of an object W to be measured can be obtained with high accuracy.