Rolling bearing fault feature extraction method based on signal sparse representation theory

Abstract

The invention discloses a rolling bearing fault feature extraction method based on the signal sparse representation theory, and the method comprises the following steps: constructing an over-complete dictionary representing local damages of a rolling bearing through employing a multi-stage inherent frequency unit impulse response function; recognizing the multi-stage inherent frequency and damping ratio of the rolling bearing and a sensor system from a vibration response signal through a related filtering method, and obtaining an optimized dictionary; solving a sparse coefficient through employing a matching tracking algorithm, and improving the solving speed and precision through reasonable segmentation; reconstructing an impact response signal of each segment, and obtaining the sparse representation of a fault feature signal; carrying out time domain index statistic characteristic analysis of time intervals of adjacent impact response components in a sparse signal, and diagnosing the type of a fault through combining a mean value and a mean square deviation value. The method has the advantages of an analytical method and an adaptive method, improves the precision of waveform features, and can iron out the defects that a conventional method based on Fourier transform is not suitable for rotating speed fluctuation.

Description

technical field [0001] The invention relates to the fields of rotating machinery and signal processing, in particular to a rolling bearing fault feature extraction method based on signal sparse representation theory. Background technique [0002] Rolling bearings are important components supporting rotating machinery, and their functional failure is one of the important factors leading to machine downtime. Assembly errors, distributed faults and local faults will cause abnormal vibration response signals of rolling bearings. When any component (outer ring, inner ring, rolling element and cage) of the rolling bearing has local damage (pitting, spalling, cracks, etc.) on the surface, a transient impact force will be generated when the damaged surface contacts other surfaces, which can Exciting natural frequencies including bearing elements, transducers and associated structures produces a shock response signal with resonance modulation characteristics. Through the sensor ins...

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Problems solved by technology

The above literatures only used the first-order natural frequency when constructing a complete dictionary, which cannot accurately describe the waveform characteristics of the impulse response

[0006] (2) When there is local damage to the inner ring and the rolling element, the damage position will perform a periodic motion that is the same as or related to the rotation cycle of the shaft, and periodically pass through the load zone of the bearing. At the same time, the impact force is in the sensor coordinate system The size of the projection also changes periodically, making the shock response at different times have amplitude modulation phenomenon

In the non-loaded region, the magnitude of the impact force is small, and may even be zero, resulting in some loss of shock vibration response

[0007] (3) Affected by speed fluctuations and sliding of rolling elements, there will be a certain random error in the time interval between the front and rear shock responses, which makes the response signal non-stationary, which limits the application of envelope analysis to a certain extent

However, most of the existing literature is based on the assumption of pure rolling

[0008] (4) For the rolling bearing in the gearbox, the meshing frequency component of the normal gear will be coupled with the impact response generated by the local damage of the bearing, which will reduce the signal-to-noise ratio of the fault characteristic component, and will increase the difficulty of constructing an over-complete dictionary and the sparse coefficient solution the accuracy of

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