The Enfigram: A robust method for extracting repetitive transients in rolling bearing fault diagnosis

Abstract

In the actual industrial production, the collected vibration signal often contains accidental impact or harmonic interference due to the influence of mechanical vibration or human interference. However, the current popular Fast Kurtogram (FK) method cannot accurately extract the frequency band with more fault information when processing the signal with such two-type interference. Therefore, this paper proposes a robust method called Enfigram to improve the drawback. In Enfigram method, a new statistical index is designed to select the optimal modulation frequency-band. Envelope Fourier index (Enfi) uses two Fourier transforms to transfer the interference of accidental pulse in the signal envelope to the origin, so that accidental pulse can be eliminated by low-pass filtering. Moreover, the frequency-band segmentation method based on spectrum trend can adaptively divide the fault information into a frequency band in Enfigram, which ensures the integrity of fault information. Compared with FK, Infogram and other methods, the result shows that Enfigram has better performance.