基于VMD的调制谱强度分布在齿轮故障诊断中的应用研究

GEAR FAULT DIAGNOSIS BASED ON THE VMD AND MODULATION SPECTRUM INTENSITY DISTRIBUTION

变分模态分解(Variational mode decomposition, VMD)是一种具有良好带通滤波特性的信号处理方法,它能够非递归地将实信号分解成一定数量在时域中具有准正交和稀疏特性的有限带宽模态分量。考虑到VMD分解多模态信号时的优势,为了弥补调制强度分布(Modulation intensity distribution, MID)分析多谐波调制信号时的不足,研究将VMD作为调制强度分布的前处理,提出了一种基于VMD的调制强度分布的齿轮故障诊断方法,并通过数值仿真和实验分析验证了该方法的有效性。

VMD has better band-pass filtering characteristic, which can non-recursively decomposition a real-valued multi-composition signal into a discrete number of quasi-orthogonal band-limited sub-signals with specific sparsity properties in the spectral. Modulation intensity distribution(MID) combined with VMD is applied to detect second-order cyclostationary components in gear fault diagnosis. Impulsive signatures generally represent the transients in the signals and are often caused by local defect in the gear of rotating machinery. Detecting these signatures is vital for mechanical signal processing and fault diagnosis. The impulsive signatures can be successfully extracted using VMD, meanwhile, Signal-noise can be separated to some extent. It is very useful tool to MID detects modulation components. However, when the analyzed signal contains multiple modulations usually mixed with other harmonic components, visual examination of the spectrum may not be accurate for identification of all carriers together with their modulation signals. Considering the shortcomings of MID in the analysis of multi-harmonic modulation signals, VMD is used as the signal preprocessing before MID analysis. Results of simulation and the experimental analysis have demonstrated the effectiveness of the method.