Shape Measurement Error Correction Using Calibration Probes
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Solution Overview
Problem
Conventional shape measurement methods face errors due to the measurement object moving in directions orthogonal to the intended measurement direction, leading to inaccuracies in surface shape estimation.
Innovation Solution
A shape measurement method and device that utilize a calibration process involving rotationally symmetric calibration objects and probes to estimate and correct for movement errors, ensuring accurate surface shape measurement by acquiring and correcting data based on the errors in probe-object distance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measurement object is moved in a first direction for shape measurement, then the surface shape along the first direction can be measured, but the measurement object may also move in a second direction (crossing direction) causing measurement errors
Solution Approach 1:
A calibration measurement object is introduced as an intermediary to estimate and correct measurement errors. The calibration object undergoes the same movement process as the actual measurement object, allowing the system to quantify and compensate for crossing-direction movements through calibration data processing
Solution Approach 2:
The system changes parameters by acquiring measurement data from multiple directions (first direction and second direction) and uses these parameter changes to calculate correction values. The correction values are derived by analyzing how the calibration object's position changes in both directions and applying these corrections to the actual measurement data
2Device complexity
If conventional single-direction measurement is used, then the measurement process is simple, but measurement errors occur due to uncorrected crossing-direction movement
Solution Approach 1:
The measurement process is segmented into multiple components: calibration measurement object acquisition, first direction measurement, second direction measurement, error calculation, and correction application. This segmentation allows each component to be optimized independently while working together to achieve high precision
Solution Approach 2:
The calibration measurement object is measured beforehand to establish correction values before actual shape measurement. This preliminary calibration action allows the system to pre-calculate error compensation parameters that will be applied during subsequent measurements of the actual measurement object
Data Source
AI summary
A shape measurement method includes: acquiring first data of a change of a distance between a first probe and a calibration measurement object and acquiring second data of a change of a distance between a second probe and the calibration measurement object while moving the calibration measurement object in a first direction, the calibration measurement object being rotationally symmetric around an axis parallel to the first direction, the first probe and the second probe being arranged in a second direction orthogonal to the first direction; estimating an error of the movement included in the first data based on the first and second data; acquiring third data of a change of a distance between the first probe and a measurement object while moving the measurement object relative to the first probe in the first direction; and correcting the third data by using the error.