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Mathematical Problems in Engineering
Volume 2015 (2015), Article ID 137274, 10 pages
Research Article

Gear Crack Level Classification Based on EMD and EDT

1The Sixth Department, Mechanical Engineering College, No. 97 Heping West Road, Xinhua District, Shijiazhuang, Hebei 050003, China
2Lanzhou Maintenance Centre, No. 27 Fanjiaping Road, Xigu District, Lanzhou, Gansu 730060, China

Received 3 July 2014; Accepted 27 October 2014

Academic Editor: Wenbin Wang

Copyright © 2015 Haiping Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Gears are the most essential parts in rotating machinery. Crack fault is one of damage modes most frequently occurring in gears. So, this paper deals with the problem of different crack levels classification. The proposed method is mainly based on empirical mode decomposition (EMD) and Euclidean distance technique (EDT). First, vibration signal acquired by accelerometer is processed by EMD and intrinsic mode functions (IMFs) are obtained. Then, a correlation coefficient based method is proposed to select the sensitive IMFs which contain main gear fault information. And energy of these IMFs is chosen as the fault feature by comparing with kurtosis and skewness. Finally, Euclidean distances between test sample and four classes trained samples are calculated, and on this basis, fault level classification of the test sample can be made. The proposed approach is tested and validated through a gearbox experiment, in which four crack levels and three kinds of loads are utilized. The results show that the proposed method has high accuracy rates in classifying different crack levels and may be adaptive to different conditions.