基于VMD-MOMEDA级联特征增强的滚动轴承故障诊断方法研究

Rolling bearing fault diagnosis via cascaded feature enhancement using VMD-MOMEDA

  • 摘要: 针对微弱故障状态下滚动轴承故障特征难以分离与提取的问题,提出一种基于VMD-MOMEDA的级联特征增强方法。以信息熵、包络熵、排列熵与样本熵为独立优化目标,采用金豺优化算法对VMD关键参数(模态数K和惩罚因子Alpha)分别寻优,获得4套最优参数并对同一信号进行4次分解得到IMF集合。为筛选有效分量,构建融合“多熵+峭度”的综合评分指标,在各IMF集合内排序并选取Top-4分量。对所选分量进行二级MOMEDA解卷积增强:首先经MOMEDA-1增强并组内叠加得到熵级融合信号,再对各熵级融合信号进行MOMEDA-2增强,最后对4条熵级增强信号跨熵路径平均融合得到最终增强信号,并通过包络谱提取故障特征频率实现诊断。试验结果表明,该方法可显著增强周期冲击成分、抑制背景噪声,使故障特征频率及其谐波在包络谱中更突出。

     

    Abstract: To address the problem of difficulty in separating and extracting fault characteristics in weak fault conditions of rolling bearings, a cascaded feature enhancement method based on "VMD-MOMEDA" is proposed. With information entropy, envelope entropy, permutation entropy and sample entropy as independent optimization objectives, the golden jackal optimization algorithm is used to optimize the key parameters (K, Alpha) of VMD separately, obtaining four sets of optimal parameters and decomposing the same signal four times to obtain the IMF set. To screen out effective components, a comprehensive scoring index integrating "multiple entropy + kurtosis" is constructed. Within each IMF set, they are sorted and the top-4 components are selected. Subsequently, secondary MOMEDA deconvolution enhancement is performed on the selected components: firstly, the entropy-level fusion signal is obtained by enhancing with MOMEDA-1 and superimposing within the group, then the entropy-level fusion signals are enhanced with MOMEDA-2; finally, the four entropy-level enhanced signals are averaged in a secondary arithmetic operation to obtain the final enhanced signal, and the fault feature frequency and its harmonics are extracted from the envelope spectrum for diagnosis. Experimental results show that this method can significantly enhance the periodic impact components, suppress background noise, and make the fault feature frequency and its harmonics more prominent in the envelope spectrum.

     

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