一种改进的MP-WVD滚动轴承信号时频分析方法

针对魏格纳维利分布(WVD)方法直接对轴承振动信号进行分析时存在交叉干扰项的问题,提出一种基于改进匹配追踪(matching pursuit,MP)算法与WVD的滚动轴承信号时频分析方法。首先,根据对轴承振动信号的分析,确定MP算法中字典原子的基函数,并通过相关滤波法确定原子参数,完成字典构造。然后,利用快速傅里叶变换(fast Fourier Transform,FFT)计算信号与字典中原子的互相关谱,替代MP算法中的内积运算,对信号进行稀疏表示,迭代过程中根据残差信号的频谱更新字典中的频率参数。最后,对稀疏表示结果中的原子进行WVD计算,并以原子对应系数为权重将各原子的时频表示线性叠加,完成信号的时频分析。实验结果表明,有效提高了MP算法的计算速度,并且与3种WVD改进算法相比,本文方法时频分析结果的时频聚集程度更高,可以更好地克服WVD方法中的交叉干扰项,为滚动轴承信号的时频分析提供新的解决方法。

Improved MP-WVD time-frequency analysis method for rolling bearing signal

Aiming at the problem of cross interference in the analysis of bearing vibration signals by Wigner-Ville distribution (WVD)method, a time-frequency analysis method based on improved matching pursuit (MP) algorithm and WVD is proposed. Firstly, based onthe analysis of bearing vibration signal, the basis function of dictionary atoms in the MP algorithm is determined, and atomic parametersare determined by correlation filtering method to complete the dictionary construction. Then, fast Fourier transform ( FFT) is used tocalculate the cross-correlation spectrum between the signal and the atoms in the dictionary, and instead of the inner product operation inMP algorithm, the signal has the sparse representation, and the frequency parameters in the dictionary are updated according to thespectrum of the residual signal during the iteration process. Finally, the atoms in the sparse representation results are calculated byWVD, and the time-frequency representation of each atom is linear overlapping with the corresponding atomic coefficient as the weight tocomplete the time-frequency analysis of the signal. The experimental results show that it effectively improves the computing speed of MPalgorithm, and compared with other three improved WVD algorithms, the time-frequency aggregation degree of the time-frequencyanalysis results of this paper method is higher, which can better overcome the cross interference term in the WVD method, and providea new solution for the time-frequency analysis of the rolling bearing signal.