Convolutional neural network-based hidden Markov models for rolling element bearing fault identification

2018 ◽  
Vol 144 ◽  
pp. 65-76 ◽  
Author(s):  
Shuhui Wang ◽  
Jiawei Xiang ◽  
Yongteng Zhong ◽  
Yuqing Zhou
Author(s):  
W B Xiao ◽  
J Chen ◽  
G M Dong ◽  
Y Zhou ◽  
Z Y Wang

This paper presents a novel multichannel fusion approach based on coupled hidden Markov models (CHMMs) for rolling element bearing fault diagnosis. Different from a hidden Markov model (HMM), a CHMM contains multiple state sequences and observation sequences, and hence has powerful potential for multichannel fusion. In this study, a two-chain CHMM is employed to integrate the two-channel vibration signals collected from bearings, i.e. the horizontal and vertical vibration signals. Efficient probabilistic inference and parameter estimation algorithms are developed for the model. An experiment was carried out to validate the proposed approach. Normalized wavelet packet energy and wavelet packet energy entropy are extracted as features for classification respectively. Then, the results of the proposed approach are compared with those of the currently used approach based on HMMs and one-channel signals. The results show that the proposed approach is feasible and effective to improve the classification rate.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yanli Yang ◽  
Peiying Fu

A method based on wavelet and deep neural network for rolling-element bearing fault data automatic clustering is proposed. The method can achieve intelligent signal classification without human knowledge. The time-domain vibration signals are decomposed by wavelet packet transform (WPT) to obtain eigenvectors that characterize fault types. By using the eigenvectors, a dataset in which samples are labeled randomly is configured. The dataset is roughly classified by the distance-based clustering method. A fine classification process based on deep neural network is followed to achieve accurate classification. The entire process is automatically completed, which can effectively overcome the shortcomings such as low work efficiency, high implementation cost, and large classification error caused by individual participation. The proposed method is tested with the bearing data provided by the Case Western Reserve University (CWRU) Bearing Data Center. The testing results show that the proposed method has good performance in automatic clustering of rolling-element bearings fault data.


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