Rotor crack fault diagnosis method based on variational modal decomposition and gray co-occurrence matrix

Abstract

The invention provides a rotor crack fault diagnosis method based on variational modal decomposition and a gray co-occurrence matrix, and belongs to the field of crack fault diagnosis. The method comprises the following steps of collecting a vibration signal; performing variational modal decomposition on the collected signal; generating a symmetric polar coordinate image for each IMF component; converting the symmetric polar coordinate images into gray images; generating the gray co-occurrence matrix by the gray images, and extracting image texture features to serve as feature parameters; selecting a feature statistics entropy of the gray co-occurrence matrix; obtaining the ith IMF component of a certain working condition; calculating average entropies of samples in corresponding states infour directions; collecting a plurality of to-be-diagnosed samples, and extracting eigenvectors; calculating Mahalanobis distances; and comparing values of d1 and d2 of to-be-detected samples, wherein the to-be-detected samples with the relatively short comprehensive distances are the states corresponding to the to-be-diagnosed samples. According to the method, the deficiency that the gray co-occurrence matrix is merely adopted for processing a rotor crack fault signal is overcome, so that the rotor crack fault diagnosis can be well completed.

Description

【Technical field】 [0001] The invention relates to the field of fault diagnosis of rotating machinery, in particular to a method for fault diagnosis of rotor cracks based on variational mode decomposition and gray level co-occurrence matrix. 【Background technique】 [0002] With the accelerated pace of industrialization, the application of rotating machinery is becoming more and more extensive. Such mechanical equipment, such as aerospace engines, wind turbines, rocket engines, etc., play an important role in aviation, energy, transportation, petrochemical and other industrial fields. [0003] For defects in the rotor processing process or the material itself, the presence or absence of cracks can be reliably detected by ultrasonic technology before the rotor is installed and the official work is completed. The rotor, the core component of rotating machinery, often suffers from stress concentration due to the influence of rapidly changing thermal and mechanical stresses under...

AI Technical Summary

Problems solved by technology

Empirical mode decomposition has no mathematical theory basis, and the algorithm uses recursive screening to decompose successively, which cannot reverse error correction, and there is modal aliasing phenomenon

The iterative calculation of local mean decomposition is large, and it is easy to produce endpoint effects

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