Wigner-Ville分布复小波相似性评价及应用

针对常规特征量对轴承早期故障不敏感问题,基于不同状态下振动信号时频分布的结构差异,融合WignerVille时频分析和复小波变换的优点,提出了基于复小波变换的Wigner-Ville时频分布相似性评价指数(WignerVille distribution-complex wavelet structural similarity,简称WVD-CWSS),实现时频分布相似性的定量评价,并用于轴承早期状态评估。首先,对振动信号进行Wigner-Ville时频分布;其次,进行复小波变换,获取不同状态下的二维时频分布结构相似性复小波指数;最后,对滚动轴承全寿命试验数据进行了对比试验。结果表明,所提取的WVDCWSS特征对滚动轴承的早期损伤更敏感。

Complex Wavelet Structural Similarity Evaluation of Wigner-Ville Distribution and Bearing Early Condition Assessment

The conventional features are not sensitive to the early fault of bearing. Therefore, in this paper a method combining the advantages of Wigner-Ville time-frequency analysis and complex wavelet transform (CWT) is proposed based on the structural difference of time-frequency distribution in different states. Structural similarity index Wigner-Ville distribution-complex wavelet structural similarity (WVD-CWSS) is calculated by the method, which can be employed to quantitatively evaluate the similarity of time frequency distributions in different states. The proposed method is applied on the early damage assessment of bearing. Firstly, the original vibration signal is transformed to Wigner-Ville distribution by using Wigner-Ville time-frequency transform. Secondly, the complex wavelet transform is performed on the Wigner-Ville time-frequency distributions. Finally, the complex wavelet structural similarity index of the two-dimensional distribution structure is calculated. The results for the full lifetime vibration datasets of rolling bearing indicate that the feature extracted in this paper can detect the early damage of the rolling bearing easier than conventional features.