Self-adaptive noise reduction method based on EMD decomposition and wavelet threshold value

Abstract

The invention relates to a self-adaptive noise reduction method based on empirical mode decomposition and a wavelet threshold. Firstly, EMD (empirical mode decomposition) is carried out on a noisy bearing vibration signal to obtain limited intrinsic mode components imf(t), the step replaces a traditional wavelet decomposition part, and the problem that wavelet basis function types and decomposition layers need to be preset in traditional wavelet decomposition is solved; then a proper threshold value and a threshold value function for the noisy imf(t) are respectively selected for processing, and an estimated f(imf<j,k>(t)) is obtained; and finally, loop iteration is carried out on the estimated f(imf<j,k>(t)) until the RMSE denoising condition is optimal. According to the method, theproblem that the optimal denoising effect is achieved by manually and repeatedly setting the number of decomposition layers during traditional wavelet reconstruction is solved.

Description

technical field [0001] This patent application belongs to the technical field of fault detection of electromechanical equipment bearings, and more specifically relates to a bearing signal noise reduction method based on EMD decomposition (empirical mode decomposition) and adaptive algorithm of wavelet threshold. Background technique [0002] The normal operation of large rotating machinery plays an important role in metal smelting, petrochemical, power system, textile machinery, aerospace and other industries. , rapidity, accuracy requirements are getting higher and higher. For example, in a large-scale thermal power plant, once some important mechanical bearings fail, it will cause certain hidden dangers to the stable operation of the rotating machinery, and even cause a series of catastrophic disasters such as damage to machinery and equipment, personal safety accidents, etc. as a result of. At home and abroad, destructive accidents frequently occur due to failure of rot...

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Problems solved by technology

[0005] The technical problem to be solved in the present invention is to provide an adaptive noise reduction method based on EMD decomposition and wavelet threshold, which can solve the problems of wavelet decomposition layer number selection and wavelet basis function selection, so as to perform noise reduction processing on bearing vibration signals, extract output the required vibration signal

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