Laser Interferometer Spatial Correction for Rotation Center 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 that offset the rotation center of a laser interferometer, leading to reduced precision in spatial accuracy correction.
Innovation Solution
A spatial accuracy correction method and apparatus that divides measurement points into multiple lines, applying unique first and second correction constants for each measurement line to account for changes in the rotation center and stylus offset, allowing for precise correction of positional errors even when the rotation center's position changes due to temperature drift or other factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spatial accuracy correction methods are used with a single correction constant, then the correction process is simple, but accuracy is reduced when the rotation center offsets due to temperature drift or external impacts
Solution Approach 1:
The patent divides measurement points into multiple measurement lines and applies different correction constants to each measurement line. This segmentation allows the system to account for rotation center offsets that occur during measurement, as each measurement line can have its own correction constants calculated independently based on the specific conditions of that line.
Solution Approach 2:
The patent changes the correction parameters by introducing multiple correction constants (first correction constant for measured length values, second correction constant for rotation center coordinates) instead of using a single correction constant. This parameter change enables the system to adapt to temperature drift and external impacts that cause the rotation center to offset.
2Measurement precision
If multiple correction constants are applied for each measurement line, then spatial accuracy correction precision is improved, but the correction process becomes more complex
Solution Approach 1:
The measurement process is segmented into multiple measurement lines, with each line processed independently using its own correction constants. This segmentation reduces the complexity of calculating multiple correction constants for all points at once, as the calculation can be performed line-by-line.
Solution Approach 2:
The patent performs preliminary actions by dividing measurement points into measurement lines before conducting the actual measurement and correction process. This preliminary organization simplifies the subsequent application of correction constants, as the system already has a structured framework for applying corrections line-by-line.
3Productivity
If a single correction constant is used for all measurement points, then the correction process is fast and simple, but errors in measured length values are incorporated into the correction
Solution Approach 1:
By segmenting measurement points into multiple measurement lines, the patent enables parallel processing of correction calculations for different lines. This maintains efficiency while improving precision, as each line's correction constants can be calculated and applied independently without affecting other lines.
Solution Approach 2:
The patent changes from a single correction constant parameter to multiple correction constant parameters (first and second correction constants for each measurement line). This parameter change allows the system to account for variations in measurement conditions across different lines while maintaining efficient correction processing.
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 enables highly accurate spatial accuracy correction by inhibiting the incorporation of errors in the measured length values, resulting in a more precise correction parameter calculation and improved positioning accuracy.
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 method that corrects an error in positioning in a positioning mechanism by using a measurable length value measured by a laser interferometer and a measured value for spatial coordinates measured by the positioning mechanism. The method includes a measurement step in which a retroreflector affixed to a displacer is displaced to a plurality of measurement points, and the measured length value and the measured value at each of the measurement points is acquired; and a parameter calculation step in which a correction parameter is calculated based on the measured value, the measured length value, and the coordinates of a rotation center of the tracking-type laser interferometer. A first correction constant is applied to the measured length value for each measurement line, and a second correction constant different from the first correction constant is applied to the coordinates of the rotation center of the interferometer for each measurement line.