Redundant Interferometer Calibration for Multi-Axis Laser Displacement
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Solution Overview
Problem
Current methods for calibrating installation errors in multi-axis laser interferometer systems are complex and require auxiliary sensors, making them inefficient for achieving nanometer or sub-nanometer level accuracy.
Innovation Solution
A method involving a redundant interferometer is introduced, which establishes a coordinate system and uses a three-degree-of-freedom displacement calculating model to calibrate installation errors without additional sensors by measuring displacement at multiple points and solving for installation error angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If other auxiliary sensors are used to calibrate the installation error, then the calibration can be performed, but the calibration process becomes complicated and requires additional sensors
Solution Approach 1:
The laser interferometer system performs self-calibration using its own redundant interferometer as a reference, eliminating the need for external auxiliary sensors. The system uses its measured values from multiple interferometers to calculate and correct installation errors internally, making the calibration process self-contained and simpler
Solution Approach 2:
A redundant interferometer is introduced as an intermediary reference element that provides a known reference axis. This intermediary component enables the calibration process by serving as a baseline for comparing and calculating installation errors of other interferometers without requiring external auxiliary sensors
2Ease of operation
If a redundant interferometer is added to the system, then the calibration process is simplified and no auxiliary sensors are needed, but the system hardware complexity increases
Solution Approach 1:
The redundant interferometer serves multiple functions: it acts as a reference for calibration, provides additional measurement data for error calculation, and enables the system to perform self-diagnosis and correction. This multi-functionality justifies the added hardware by providing comprehensive benefits beyond simple redundancy
Solution Approach 2:
The calibration approach transitions from using external auxiliary sensors (adding complexity in one dimension) to using internal redundant interferometer measurements (adding a measurement dimension). By measuring along multiple axes and using the redundant reference, the system gains additional measurement dimensions that enable simpler calibration algorithms
Data Source
AI summary
Provided is a method for calibrating an error of installation of an interferometer in a multi-axis laser displacement measurement system, including: adding one or more redundant interferometers in a laser interferometer displacement measurement system; then establishing displacement calculating equations containing installation error of the laser interferometer and obtaining redundant measurement information by continuously measuring displacement information of multiple points, wherein the number of the combined displacement calculating equations is equal to the number of unknown quantities; and further solving the equation set to obtain the installation error of the interferometer. With a redundant arrangement of the laser interferometer, self-calibration of the installation error thereof can be achieved. A problem of difficulty in calibration of the installation error of the multi-axis interferometer in industrial application can be solved without assistance of other displacement sensors with higher precision.