Envelope analysis method based on variational-mode decomposition filter

Abstract

The invention discloses an envelope analysis method based on variational-mode decomposition filter. According to the method, an original signal is decomposed by using a variational-mode decomposition method; a noise component and a trend term in a decomposition result are eliminated by using data rearrangement and replacement; a signal after first-time filtering is analyzed by using a spectral kurtosis method to obtain a center frequency and a bandwidth of an optimal filter; second-time filtering is carried out on the signal after the first-time filtering by using the filter; an envelop analysis is carried out on the signal after the second-time filtering by using a rational spline iterative smoothing envelope analysis method; and then a fault type of a rotary machine is determined according to an envelope spectrum. According to the invention, the method is suitable for processing a rotary mechanical fault signal with complicated processing; and a fault type of a rotary machine can be determined accurately. Moreover, the method having high noise immunity and robustness is suitable for engineering application.

Description

technical field [0001] The invention relates to the field of state monitoring and fault diagnosis of rotating machinery, in particular to an envelope analysis method based on variational mode decomposition filtering. Background technique [0002] Envelope analysis technique is widely used in fault diagnosis of gears and rolling bearings. The existing envelope analysis technology has the following three defects: ① The existing envelope analysis technology either directly analyzes the original signal, or only analyzes the original signal after simple filtering, so the existing method It is easily disturbed by noise, trend and other components, resulting in low analysis accuracy of the existing technology; ②The existing envelope analysis technology is based on the Hilbert transform, and the Hilbert transform requires that the signal to be analyzed must be a single component Narrowband signals, otherwise the frequency modulation part of the signal will pollute the amplitude env...

AI Technical Summary

Problems solved by technology

The existing envelope analysis technology has the following three defects: ① The existing envelope analysis technology either directly analyzes the original signal, or only analyzes the original signal after simple filtering, so the existing method It is easily disturbed by noise, trend and other components, resulting in low analysis accuracy of the existing technology; ②The existing envelope analysis technology is based on the Hilbert transform, and the Hilbert transform requires that the signal to be analyzed must be a single component Narrowband signals, otherwise the frequency modulation part of the signal will pollute the amplitude envelope analysis results of the signal, but the current signals to be analyzed do not strictly meet the conditions of single component and narrowband, which will lead to the existing technology is easy to The problem of misjudgment occurs; ③ The envelope spectrum obtained by traditional methods has endpoint effects

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