Research on the demodulation method based on the wavelet analysis

Based on wavelet analysis method and Hilbert envelop demodulation, a method for the fault diagnosis of rolling bearings is proposed in this paper. The local Hilbert demodulation and local wavelet transform are introduced respectively. The wavelet transform is used to translate vibration signals into time-scale representation. Then, an envelope signal can be obtained by envelop spectrum analysis of wavelet coefficients of high scales from which the faults in a roller bearing could be diagnosed. Vibration signals measured from roller bearings test rig with outer race faults are analyzed by the proposed method. The results show that the proposed method can diagnose the faults in a roller bearing and fault patterns can be identified.