中国激光, 2019, 46 (1): 0104001, 网络出版: 2019-01-27
调频连续波激光测距系统的振动补偿仿真研究 下载: 856次
Simulation of Vibration Compensation in Frequency-Modulated Continuous-Wave Laser Ranging System
测量 四波混频 调频连续波 振动 等光频间隔重采样 measurement four-wave mixing frequency-modulated continuous-wave vibration equispaced-phase resampling
摘要
在双光路调频连续波激光测距过程中, 振动将光程差变化转为拍频信号不需要的相位调制, 并在拍频信号中引入多普勒频移, 导致拍频信号的频谱发生严重展宽和频移, 无法根据拍频频率计算距离值。为解决该问题, 提出一种基于四波混频效应的振动补偿方法, 该方法利用四波混频技术产生与原频率扫描信号扫描方向相反的新频率扫描信号, 通过两个频率扫描信号的测量拍频信号计算距离值。结果表明:当扫描带宽为10 nm, 待测距离为5 m, 待测目标以2 Hz的频率进行行程为100 μm的周期性位移时, 基于四波混频效应的振动补偿方法能有效消除振动对测距的影响, 测量标准差由补偿前的1.062 mm减小为29 μm; 该方法无需测量振动位移便可直接获取消除振动影响的距离值, 极大地简化了系统的硬件部分。
Abstract
In the process of dual-path frequency-modulated continuous-wave laser ranging, the vibration converts the optical-path difference into an unnecessary phase modulation of a beat-frequency signal. In addition, the Doppler shift is introduced into this beat-frequency signal, which results in the serious broadening and frequency shift in the spectrum of beat-frequency signals. Thus the distance cannot be calculated according to the beat-frequency. To solve this problem, we propose a vibration compensation method based on the four-wave mixing effect, in which the four-wave mixing technology is utilized to generate a new frequency-sweeping signal opposite to the sweeping direction of the original frequency-sweeping signal, and the distance value can be calculated according to the measured beat-frequency signal of two frequency-sweeping signals. The results show that when the sweeping bandwidth is 10 nm, the measurement distance is 5 m and the target has a periodic displacement of 100 μm at a frequency of 2 Hz, the influence of vibration on laser ranging can be effectively eliminated with the vibration-compensation method based on the four-wave mixing effect, and the measurement standard deviation is reduced from 1.062 mm before compensation to 29 μm. In this method, the distance value after elimination of vibration influence can be directly obtained without the need of measuring vibration displacement, and the hardware part of the system is greatly simplified.
李雅婷, 张福民, 潘浩, 史春钊, 曲兴华. 调频连续波激光测距系统的振动补偿仿真研究[J]. 中国激光, 2019, 46(1): 0104001. Li Yating, Zhang Fumin, Pan Hao, Shi Chunzhao, Qu Xinghua. Simulation of Vibration Compensation in Frequency-Modulated Continuous-Wave Laser Ranging System[J]. Chinese Journal of Lasers, 2019, 46(1): 0104001.