NMD, spectral kurtosis and smoothness iteration envelope analysis method for rolling bearing

Abstract

The invention provides an NMD, spectral kurtosis and smoothness iteration envelope analysis method for a rolling bearing. The method comprises the steps that a non-linear mode decomposition method is used to decompose an original signal; data rearrangement and substitution operation are used to eliminate noise component and trend term in a decomposition result; a spectral kurtosis method is used to analyze the signal after the first time of filtering to acquire the center frequency and bandwidth of an optimal filter; the filter is used to filter the signal after the first time of filtering again; a smoothness iteration envelope analysis method is used to carry out envelope analysis on the signal after the second time of filtering; and finally the fault type of the rolling bearing is determined according to the envelope spectrum. The method provided by the invention is suitable for dealing with complex rolling bearing fault signals, can accurately determine the fault type of the rolling bearing, has good noise resistance and robustness, and is convenient 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 NMD, spectrum kurtosis and smooth iterative envelope analysis method of a rolling bearing. 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 th...

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; ③The envelope spectrum obtained by traditional methods has endpoint effects

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