基于FPGA的激光多普勒微振动检测及信号处理方法

Laser Doppler Microvibration Detection and Signal Processing Based on FPGA

摘要:

为实现微弱振动信号的实时、高精度解调,提出基于现场可编程逻辑门阵列(FPGA)的激光多普勒微弱振动检测及信号处理方法。采用全光纤结构的光学系统,振动信号处理系统则以FPGA为核心设计。改进相位解缠模块,在增大振动的测量范围同时,使其能适用于简谐振动与复杂振动。通过模拟振动实验验证了改进后相位解缠模块,且当振幅在80μm以内时,测量精度在5‰以内。通过对压电陶瓷实际振动目标测振实验,其频率测量误差在1Hz以内,振幅与频率的测量精度均在1%以内。实验验证了该振动信号处理方案对于扩大振动测量范围与实现高精度目标振动解调的有效性。

Abstract:

In order to realize the real-time and high-precision demodulation of microvibration signal, a method of laser Doppler microvibration detection and signal processing based on FPGA is proposed. The optical system with all-fiber structure is adopted, and the vibration signal processing system is designed with FPGA as the core. The phase unwrapping module is improved to enlarge the measuring range of vibration and make it suitable for simple harmonic vibration and complex vibration. The improved phase unwrapping module is verified by simulated vibration experiments, and when the amplitude is less than 80μm, the measurement accuracy is less than 5‰. Through the vibration measurement experiment of the actual vibration target of piezoelectric ceramics, the frequency measurement error is less than 1Hz, and the measurement accuracy of amplitude and frequency is less than 1%. The experimental results show that the vibration signal processing scheme is effective in expanding the vibration measurement range and realizing high-precision target vibration demodulation.