Spatial Accuracy Correction for Positioners Under Temperature Drift
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Solution Overview
Problem
Conventional spatial accuracy correction methods in positioning mechanisms, such as coordinate measuring machines, fail to accurately correct for errors caused by temperature drift and external impacts, leading to reduced precision in positioning due to incorporated positional offsets in measured length values.
Innovation Solution
A spatial accuracy correction method that involves repeated measurements at specific measurement points, with the option to re-measure all points if a predetermined threshold of error is exceeded, using a tracking-type laser interferometer and a control device to adjust the position of a retroreflector and calculate correction parameters with different constants for each measurement line, thereby accounting for positional offsets and temperature drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spatial accuracy correction methods are used, then the correction process is simple and quick, but the accuracy is reduced due to temperature drift and external impacts causing positional offsets
Solution Approach 1:
The patent applies preliminary action by performing repeated measurements at specific measurement points before final correction parameter calculation. The system measures positional offsets at multiple points, identifies points exceeding threshold values, and uses these preliminary measurements to determine whether re-measurement of all points is necessary. This preliminary detection and selection process ensures that temperature drift and external impact effects are accounted for before final correction, improving reliability without sacrificing too much time.
Solution Approach 2:
The patent implements feedback by continuously monitoring measurement results and comparing them against threshold values. When positional offset measurements exceed predetermined thresholds, the system triggers re-measurement of all measurement points. This feedback loop ensures that correction parameters are only finalized when measurement stability is confirmed, preventing propagation of errors caused by temperature drift or external impacts, thereby improving both accuracy and reliability.
2Measurement precision
If repeated measurements and re-measurement protocols are implemented, then measurement precision and reliability are improved, but measurement time and process complexity increase
Solution Approach 1:
The patent applies local quality by focusing repeated measurements only at specific measurement points where positional offsets exceed predetermined threshold values, rather than uniformly repeating measurements at all points. The system identifies problematic local areas (measurement points with large offsets) and directs additional measurement resources there, while points within acceptable ranges proceed to correction parameter calculation. This localized approach maintains high measurement precision where needed while minimizing unnecessary time consumption at already-acceptable points.
Solution Approach 2:
The patent implements partial action by conditionally performing re-measurement of all measurement points only when necessary (when threshold values are exceeded), rather than always performing complete re-measurement sequences. The system selectively applies the full re-measurement protocol based on actual measurement conditions, performing partial correction processes when measurement stability is sufficient and complete re-measurement only when required. This reduces average measurement time while maintaining precision through targeted repeated measurements at critical points.
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 allows for high-accuracy correction parameters to be calculated, ensuring precise spatial accuracy by identifying and mitigating errors caused by temperature drift and external impacts, thereby improving the overall correction process.
Implementation Method 1
a laser interferometer having a reference point and measuring a distance from the reference point to the retroreflector
Data Source
AI summary
A spatial accuracy correction apparatus performs a spatial accuracy correction of a positioner displacing a displacer to a predetermined set of spatial coordinates using a measurable length value measured by an interferometer and a measurable value of the set of spatial coordinates of the displacement body that is measured by the positioner. The measured length value and the measured value for each measurement point are acquired by displacing the displacement body to a plurality of measurement points in order, one or more repeated measurements are conducted for at least one of the plurality of measurement points being measured after conducting measurement of the measured length value and the measured value for each of the plurality of measurement points, and the plurality of points are measured again when a repeat error of the measured length value is equal to or greater than a threshold value.