Weak fault feature extraction of rolling element bearing based on variational mode extraction and multi-objective information fusion band-pass filter

Hongchao Wang,Zhiwei Li,Wenliao Du,Haiyi Li,Jiale Hu

doi:10.21595/jve.2021.22067

Hongchao Wang, Zhiwei Li + Show 3 more

Open Access

https://doi.org/10.21595/jve.2021.22067

Copy DOI

Abstract

Aiming at solving the difficulty in extracting early weak fault features of rolling element bearing (REB), a feature extraction method by combing variational mode extraction (VME) with multi-objective information fusion band-pass filter (MIFBF) is proposed. This method is based on the advantage of the VME in filtering out the interference signals and the enhancement effect of the MIFBF on the impact characteristic signals. Firstly, VME is used as the signal preprocessing method to filter out the interference noise. Then, the filtered signal is taken as the target signal, and then MIFBF is used to analyze it to obtain the optimal band-pass filter parameters-center Frequency and bandwidth, thereby constructing the optimal band-pass filter. Finally, further filter the target signal based on the constructed optimal band-pass filter and apply envelope demodulation spectral (EDS) analysis on the filtered signal. At last, satisfactory fault feature extraction effect can be achieved. To obtain key parameters of the optimal band-pass filter, this paper proposes a method based on time and frequency domain fusion indexes to balance the extraction of impact characteristics and cyclostationary characteristics while REB failure occurs. Compared with the existed single index based on time domain or frequency domain, better results could be obtained. Effectiveness and superiority of the proposed method are verified through simulation and experiments.

Highlights

envelope demodulation spectral (EDS) is the most commonly used method for fault diagnosis of rolling element bearing (REB)
EDS analysis is applied on the filtered vibration signal and the fault characteristic frequency (FCF) with its harmonics of the faulty REB are extracted
Apply EDS on the filtered signal and the corresponding result is shown on Fig. 5(d), and it can be seen that both the harmonic frequency of the FCF and modulation phenomenon are extracted basing on the last EDS result, which verifies the superiority of the proposed method

Summary

Introduction

EDS is the most commonly used method for fault diagnosis of REB. Normally, a band-pass filter is needed to be constructed to filter the original signal of REB for better effect of EDS. An optimal band pass filter establishment method basing on the fusion index of time and frequency domain for balancing the enhancement of impulsive and cyclostationary characteristics is used to analyze the extracted specific mode. Selection of the basis function has an important influence on the analysis result: the better analysis result could be obtained with the closer the basis function to the shape of the target extraction signal; and vice versa Based on this ideology, Anti-symmetric real Laplace wavelet filter (ARLW) [21] has been proved to be fit for analyzing bearing impulse vibration signal while fault arises, and time-domain and corresponding frequency domain of ARLW could be calculated by the following two equations: ψ(t) ψ(f).

Flow chart of the proposed method

Simulation

Experiment

Conclusions