Fault diagnosis of rotating machinery based on improved wavelet package transform and SVMs ensemble

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• 作者：Qiao Hu ; Zhengjia He ; Zhousuo Zhang ; Yanyang Zi
• 关键词：Improved wavelet package ; Feature extraction ; Feature selection ; Distance evaluation technique ; Support vector machines ensemble ; Fault diagnosis
• 刊名：Mechanical Systems and Signal Processing
• 出版年：2007
• 出版时间：February 2007
• 年：2007
• 卷：21
• 期：2
• 页码：688-705
• 全文大小：507 K

文摘

This paper presents a novel method for fault diagnosis based on an improved wavelet package transform (IWPT), a distance evaluation technique and the support vector machines (SVMs) ensemble. The method consists of three stages. Firstly, with investigating the feature of impact fault in vibration signals, a biorthogonal wavelet with impact property is constructed via lifting scheme, and the IWPT is carried out to extract salient frequency-band features from raw vibration signals. Then, the faulty features can be detected by envelope spectrum analysis of wavelet package coefficients of the most salient frequency band. Secondly, with the distance evaluation technique, the optimal features are selected from the statistical characteristics of raw signals and wavelet package coefficients, and the energy characteristics of decomposition frequency band. Finally, the optimal features are input into the SVMs ensemble with AdaBoost algorithm to identify the different abnormal cases. The proposed method is applied to the fault diagnosis of rolling element bearings, and testing results show that the SVMs ensemble can reliably separate different fault conditions and identify the severity of incipient faults, which has a better classification performance compared to the single SVMs.