Mechanical fault diagnosis based on all-phase FFT parameters estimation

To improve the accuracy of mechanical fault diagnosis, all-phase FFT (apFFT) is introduced to estimate individual harmonics´ frequency, amplitude and phase of fault signal. Combining with synthesized FFT/apFFT correcting method of phase difference, the frequency and amplitude estimation can be obtained by utilizing these two spectral analysis results at the position of peak spectral line. Moreover, due to apFFT´s property of phase invariance, the phase value at main spectral position can be directly taken as the original phase without any correcting operations, thus, waveform reconstruction is realized. Simulation experiment proves that fault information can be intuitively reflected by the quality of reconstructed waveform, and the corresponding type of mechanical fault based on parameters estimation can be identified.