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A Two-Dimensional Precision Level for Real-Time Measurement Based on Zoom Fast Fourier Transform
Haijin Fu1,2, Zheng Wang1,2, Xionglei Lin1,2
1Ultra-Precision Optoelectronic Instrument Engineering Center, School of Instrument Science and Engineering, Harbin Institute of Technology, Harbin 150080, China.
Micromachines
|November 25, 2023
Summary
This study introduces a novel two-dimensional precision level utilizing a zoom fast Fourier transform (FFT) algorithm for high-resolution, real-time angle measurement. The method significantly enhances angle resolution and accuracy, outperforming commercial autocollimators.
Area of Science:
- Metrology
- Optical Engineering
- Signal Processing
Background:
- Traditional angle measurement systems face limitations in achieving both high resolution and real-time measurement capabilities.
- Existing methods struggle to balance the trade-off between measurement speed and angular precision.
- The need for advanced metrology tools in precision engineering necessitates innovative solutions.
Purpose of the Study:
- To develop a two-dimensional precision level capable of real-time, high-resolution angle measurement.
- To address the inherent contradiction between high resolution and high measurement speed in angle measurement systems.
- To enhance the angle resolution and accuracy of precision leveling instruments.
Main Methods:
- Implementation of a zoom fast Fourier transform (FFT)-based decoupling algorithm integrated into a field-programmable gate array (FPGA).
- Utilization of a silicone-oil surface as the angle-sensitive interface, combined with homodyne interference principles.
- Analysis of interference fringe frequency to determine angle variations and improve frequency resolution.
Main Results:
- The proposed zoom FFT algorithm significantly enhances the frequency resolution of interference fringes, improving angle resolution.
- Real-time angle measurement was achieved by transplanting the angle decoupling process onto the FPGA board.
- Prototype testing demonstrated an improvement in angle resolution from 9 arcsec to approximately 0.1 arcsec, with repeatability of ±0.2 arcsec and accuracy of ±0.6 arcsec.
Conclusions:
- The zoom FFT-based decoupling algorithm effectively overcomes the resolution-speed trade-off in angle measurement.
- The developed two-dimensional precision level offers superior angle resolution and accuracy compared to existing methods.
- The system's real-time measurement capability and high precision validate its effectiveness for advanced metrology applications.
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