瞳面干涉激光多普勒测振

Laser Doppler Vibrometry Based on Pupil-Plane Interferometry

提出并实现了一套基于瞳面干涉和小波变换的零差激光测振系统,提高了多普勒信号的质量和信号处理精度。该系统将瞳面干涉技术引入到激光多普勒测振中,克服了像面干涉测振光路中复杂振动引起的探测光斑相对探测器偏移的现象,抑制了漂移引起的多普勒信号被调制的现象。在振动信息提取环节,采用小波脊提取算法提取信号瞬时频率,进而解算得到振动速度。将标准振动台作为振动源,磁电式速度传感器作为测量参考,通过测速与测振实验对系统性能进行验证。实验表明,所设计的系统对振动物体速度的测量与磁电式速度传感器具有一致性,对不同简谐振动参数的测量相对误差均在1.5%以内。

To improve the quality of Doppler signal and signal processing accuracy,a set of homodyne laser vibration measurement system based on pupil-plane interferometry and wavelet transform is proposed and implemented.In this system,pupil-plane interferometry is introduced into the laser Doppler vibrometry,which overcomes the phenomenon that the detection spot drifts relative to the detector caused by the complex vibration of the measured object in optical path for vibration measurement based on image-plane interferometry,and suppresses the modulation of Doppler signal caused by this kind of drift.In the session of vibration information extraction,the instantaneous frequency of signal is extracted by wavelet ridge extraction algorithm,and then the vibration velocity is calculated.With a standard shaker as the vibration source and a magnetoelectric velocity sensor as the reference,the performance of the designed system is verified through the experiments of measuring the velocity and the vibration.Experimental results show that the measurement of the velocity of a vibrating object by the designed system is consistent with the magnetoelectric velocity sensor,and the relative errors of different simple harmonic vibration parameters measured by the designed system are all within 1.5%.