Fault detection of gearbox with vibration signal analysis by a linear combination of adaptive wavelets

In this paper, we propose a novel method for identification of gear crack from the low-frequency modulated vibration signal, based on Hilbert transform and adaptive wavelet transform (AWT). Hilbert transform is used to present the envelope of the modulated vibration signal to show the modulating frequency. AWT is applied to process the modulated vibration signal by Hilbert transform. The proposed AWT can match the vibration signal with the meshing frequency and its harmonics, the coupling frequency, the carrier frequency, and their sidebands by an optimized wavelet. The model-based method by AWT is applied to extract the envelop features from the modulated vibration signal. Both simulated and experimental vibration signals are used to test the proposed method.