磁悬浮陀螺转子信号的局部均值分解降噪研究

Research on noise reduction of rotor signal of maglev gyroscopebased on local mean decomposition

磁悬浮陀螺转子电流信号对环境变化高度敏感,信号采样过程中不可避免会引入噪声,针对该问题提出一种基于局部均值分解(local mean decomposition,LMD),融合豪斯多夫(Hausdorff)距离与阈值降噪(threshold denoising,TD)的算法以减弱噪声干扰。首先对原始信号进行局部均值分解,得到若干乘积函数(PF)分量和一个余量,然后根据各PF分量与原始信号间的豪斯多夫距离判定噪声、信号分量,再对噪声分量进行阈值处理,最后将阈值处理后的噪声分量、信号分量及余量进行叠加得到重构信号,实现陀螺仪转子电流信号的降噪。仿真实验结果表明,重构信号的信噪比相对于原始信号平均提高了12.86 db,均方根误差平均降低了9.25×10^(-6)A;实测信号降噪结果表明,该降噪算法对四条导线边的滤波增益分别为40.0%、93.5%、30.8%和50.0%。

The rotor current signal of maglev gyro is highly sensitive to environmental changes,therefore,noise will inevitably be introduced in the process of signal sampling.To solve this problem,an algorithm based on local mean decomposition(LMD)and fusion of Hausdorff distance and threshold denoising(TD)is proposed to reduce noise interference.Firstly,the original signal is decomposed into several PF components and a margin.Then,the noise and signal components are determined according to the Hausdorff distance between each pf component and the original signal.Then,the noise component is denoised by threshold.Finally,the noise components,signal components and margin after thresholding are superimposed to obtain the reconstructed signal,so as to realize the reconstruction of the gyroscope rotor current signal Noise reduction.The simulation results show that the signal-to-noise ratio of the reconstructed signal is 12.86 db higher than that of the original signal,and the root mean square error is 9.25×10^(-6)A lower than that of the original signal.The de-noising results of measured signals show that the filtering gains of the de-noising algorithm for four wire sides are 40.0%,93.5%,30.8%and 50.0%respectively.