Roller Bearing Defect Identification under Variable Rotating Speed Using Hilbert-Huang Transform and Amplitude Normalization via Hardware Implemented Order-Tracking Technique

• Main Authors: Yu-sheng Lin, 林祐聖
• Other Authors: 吳天堯
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/43778807721053405346

碩士 === 國立中央大學 === 機械工程學系 === 101 === In this study, Hilbert-Huang transform (HHT) is utilized for diagnosing the roller bearing faults, such as outer race defect, inner race defect, roller defect and multi-fault, under variable rotation speed. The vibration signals are first measure through the order tracking technique, so that the vibration signals are detected with identical angle increment and thus the vibration signals are stationary without the factor of variable shaft rotation speed. The envelope signals of the measurements are analyzed by Hilbert-Huang transform approach. The features of the faulted bearings are extracted by investigating the intrinsic mode functions (IMFs) as well as the marginal Hilbert spectra. The extracted features of the faulted bearing are then re-scaled through the amplitude normalization, so that the vibration energy are not affected by the variable rotation speed. Finally, the support vector machine is employed to identify the individual defect of bearing. The same SVM structure is also used to diagnose the occurrence of multi-fault in bearings.