A Gearbox Fault Identification Method Based on Spectrum Trend and Variational Mode Decomposition

Abstract

The invention discloses a gear case fault recognition method based on spectrum trends and variation mode decomposition. The method includes the steps: firstly, acquiring vibration signals of a targetgear case; secondly, improving a variation mode decomposition method by the aid of a mode based on spectrum trends, and decomposing the vibration signals of the gear case by the improved variation mode decomposition method to obtain mode components of the vibration signals; thirdly, performing demodulation analysis on the acquired mode components to obtain characteristic frequency of each mode signal; finally, comparing the characteristic frequency and gear converting frequency of the gear case, and positioning fault sources of the gear case. According to the method, trend concepts of a time-domain range is introduced into a frequency domain range, a method for improving variation mode decomposition based on the spectrum trends is provided and effectively solves the problem that modal number needs to be preset in variation mode decomposition, center frequency is initialized by the aid of normalized x-coordinates of maximum values of the spectrum trends, and decomposed modes are more reasonable.

Description

technical field [0001] The invention belongs to the technical field of gearbox fault identification, in particular to a gearbox fault identification method based on spectrum trend and variational mode decomposition (VMD), which is a multi-component number estimation based on spectrum trend (Spectrum Trend) And based on the spectrum trend, the variational mode decomposition (Variational Mode Decomposition, VMD) algorithm is improved for the extraction of multi-component signal modes. Background technique [0002] The gearbox vibration signal has the characteristics of complex multi-component and AM-FM. The amplitude demodulation and frequency demodulation methods can avoid the complex sideband analysis in the traditional Fourier spectrum and effectively identify the fault characteristic frequency. However, a prerequisite for effective demodulation analysis of multi-component AM-FM signals is to extract effective modal components. Both wavelet transform (Wavelet Transform, WT)...

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Problems solved by technology

[0004] When the VMD method directly processes the vibration signal of the gearbox, the number of modal components needs to be preset. If the estimated number of components is too large or too small, the decomposition of the vibration signal will be unreasonable and affect the accuracy of fault identification.

In addition, different center frequency initialization methods will also cause different distributions of the decomposed modal components on the frequency spectrum, which will also have an adverse effect on fault identification

These problems also affect the wide application of VMD method in the field of gearbox fault identification

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