基于质心寻峰的调频连续波激光干涉位移传感器

Frequency-modulated continuous-wave laser interferometry displacement sensor based on centroid peak-finding

调频连续波激光干涉技术在精密测量领域中应用广泛,针对其高精度位移解调问题,本文将质心法应用于其拍频信号的解调中,提出了一种基于质心寻峰法的相位解调算法并进行实验与分析。提出的算法在对截取的拍频信号进行平滑滤波与分峰截幅等处理基础上,通过质心坐标公式得到拍频信号的质心,质心横坐标即为峰值位置,最后通过相位鉴别算法解调出位移。在仿真中设置信噪比(SNR)为15 dB,算法的相位误差为0.016 rad,位移误差为2.04 nm。搭建调频连续波激光干涉位移测量系统进行实验验证,实验结果表明:当固定距离为44 mm时,位移随机误差标准差为2.18 nm。与常规的过零点检测法进行对比分析,结果表明该算法的测量误差降低了49%,分辨率获得了提高,具有广泛的应用前景。

The frequency-modulated continuous wave laser interferometry is widely used in the field of precision measurement.Aiming at its high-precision displacement demodulation problem,this paper applies the centroid method to the demodulation of its beat signal,proposes a phase demodulation algorithm based on the centroid peak-seeking method,and carries out experiments and analysis.Based on the smooth filtering and peak clipping of the intercepted beat signal,the proposed algorithm obtains the centroid of the beat signal through the centroid coordinate formula.The abscissa of the centroid is the peak position.Finally,the phase discrimination algorithm demodulates the displacement.In the simulation,the SNR is set to 15 dB,the phase error of the algorithm is 0.016 rad,and the displacement error is 2.04 nm.A frequency-modulated continuous wave laser interference displacement measurement system was built for experimental verification.The experimental results show that when the fixed distance is 44 mm,the standard deviation of random displacement error is 2.18 nm.Compared with the conventional zero crossing detection method,the measurement error of the algorithm is reduced by 49%,the resolution is improved,and the algorithm has broad application prospects.