Gearbox Fault Diagnosis Using Two-Dimensional Wavelet Transform

In this paper, a novel technique for denoising gearbox vibration has been proposed. We first convert the vibration signal into a two-dimensional matrix such that each row of the resulting matrix contains exactly one revolution of the gear. This matrix is subsequently denoised using two-dimensional wavelet thresholding method. We apply our proposed method to an experimental data set to investigate the improvement in denoising performance. The experimental data is generated using a test rig on which different damage levels are simulated. The experimental results show that the impulses in the vibration signal can be detected easily from the denoised signal even for slight localized tooth damage. The proposed method is compared to time synchronous averaging and the combination of the time synchronous averaging and the one-dimensional wavelet denoising. The kurtosis value of the denoised signal is used for comparing the denoising performance of these three methods. The comparison study shows that the proposed method outperforms both competing methods, especially in early stages of the fault.