基于MEWT-ASCS的行星齿轮箱微弱故障特征提取

Weak Fault Diagnosis Method of Planetary Gearbox Based on Modified Empirical Wavelet Transform and Adaptive Sparse Coding Shrink Algorithm

针对强噪声背景下行星齿轮箱早期微弱故障难以提取以及经验小波变换对信号频率区间边界划分不恰当以及不能有效确定模态数目的问题,提出了一种基于改进经验小波变换(modified empirical wavelet transform,简称MEWT)和自适应稀疏编码收缩(adaptive sparse coding shrinkage,简称ASCS)的早期微弱故障特征提取方法。根据信号频谱的尺度空间表示,将原始故障信号自适应地分解为一系列的窄频带本征模态分量。利用包络谱峭度(envelope spectrum kurtosis,简称ESK)值选择敏感分量,为了进一步凸显分量中的故障信息,使用ASCS算法对敏感分量进行稀疏降噪处理,从其包络谱中即可提取到清晰的故障特征频率成分。数值仿真和实际数据分析结果表明,本研究方法能够自适应地实现故障信号的模态分解并增强微弱的故障冲击特征。此外,与经验小波变换(empirical wavelet transform,简称EWT),EWT-ASCS和ASCS进行对比,本研究方法可有效提取包含故障信息丰富的分量,经ASCS处理后信号故障特征得到凸显,实现了行星齿轮箱早期微弱故障的准确识别。

Empirical wavelet transform(EWT)is inadequate in the early weak diagnosis fault of planetary gearboxes under strong noise background,mainly due to the improper segmentation of the signal spectrum,which cannot effectively determine the number of modal components. Consequently,an early fault diagnosis method of planetary gearbox is proposed,which combines the modified empirical wavelet transform(MEWT)and adaptive sparse coding shrinkage(ASCS)algorithms. According to the scale space representation of signal frequency spectrum,the original fault signal is adaptively decomposed into a series of narrowband intrinsic mode components. Envelope spectrum kurtosis(ESK)value is used to select the sensitive component. To further highlight fault information,the ASCS algorithm is applied to sparse noise reduction for sensitive component,thus the obvious characteristic frequency information can be extracted from its envelope spectrum. Through the analysis of numerical simulation and actual data,this method can adaptively decompose the planetary gearbox fault signal and enhance weak fault impulse characteristics. In addition,compared with EWT,EWT-ASCS,and ASCS,the proposed method can effectively extract the component that contains abundant fault information,and then the signal fault characteristics are highlighted after ASCS processing,thereby realizing the accurate identification of early weak fault of planetary gearbox.