Vacuum pump vibration signal noise reduction method based on EEMD (ensemble empirical mode decomposition) and wavelet threshold

Abstract

The invention discloses a vacuum pump vibration signal noise reduction method based on EEMD (ensemble empirical mode decomposition) and a wavelet threshold; the method comprises the following steps: firstly, an original signal is subjected to EEMD to obtain a plurality of IMF (Intrinsic Mode Function) components and a remainder; secondly, all the IMF components are subjected to calculation of a normalization self-correlation function, and the IMF components are divided into a signal-dominant IMF component and a noise-dominant IMF component according to the characteristic of zero attenuation ofthe self-correlation function; then, the noise-dominant IMF component is subjected to wavelet soft threshold noise reduction processing; finally, the noise-dominant IMF component subjected to waveletsoft threshold processing and the signal-dominant IMF component are subjected to signal reconstruction with the remainder so as to obtain a noise-reduced vacuum pump vibration signal. According to the method in the invention, EEMD is adopted, so that the problems of mode aliasing, end point effect and the like caused by EEMD can be overcome, noise signals in the vacuum pump vibration signals areeffectively removed, more useful signals are well reserved, and the signal-to-noise ratio of the signals is improved.

Description

technical field [0001] The invention relates to vibration signal noise processing technology, in particular to a vacuum pump vibration signal noise reduction method based on EEMD and wavelet threshold. Background technique [0002] In recent years, my country has developed rapidly in the field of aerospace technology, and has successively launched many batches of satellites and space exploration equipment. In order to ensure the smooth operation of spacecraft equipment in complex space environments, ground simulation tests of space environments are required, among which ultra-low temperature and high vacuum are the key requirements for simulation test environments. Vacuum pump is an important equipment for ground space environment simulation, and its failure frequency is high, which will lead to the decline of vacuum pump performance and abnormal noise at low temperature. Therefore, it is necessary to carry out online fault diagnosis on the structure of the vacuum pump to d...

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Problems solved by technology

However, if there are abnormal mutations in the signal, modal aliasing and endpoint effects will occur, which will affect the noise reduction effect

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