Rolling Bearing Fault Diagnosis Based On Wavelet Packet Energy Spectrum

Rolling bearings are the most common and important general components in all kinds of machinery, whose working condition can directly affect the entire producing System’s efficiency and safety. That’s why research on fault diagnosis for rolling bearings is always the key technology of both domestic and overseas engineering field. By applying wavelet packet energy spectrum and zooming envelope analysis, a new method of rolling bearings fault diagnosis is proposed. First, the vibration signals are decomposed into individual frequency bands by the wavelet packet. The energy of every frequency band is calculated. According to the energy’s change situation, the fault frequency band is discovered. The signals of the fault frequency band are reconstructed and the reconstructed signals are analyzed by applying Hilbert transform. The characteristic frequency of fault signals is extracted. In order to enhance the resolution of envelope signals, a spectrum zooming analysis method based on Chirp Z-Transform (CZT) is used. Through processing and analyzing the practical rolling bearing experimental data, it shows that this method is effective.