Synchronous compression transformation order analysis method for rolling bearing fault diagnosis

Abstract

The invention discloses a synchronous compression transformation order analysis method for rolling bearing fault diagnosis. According to the method, firstly, SST is utilized to analyze a variable-speed vibration signal of a bearing to obtain time-frequency distribution of the vibration signal; secondly, an instantaneous frequency ridge of frequency conversion is extracted and subjected to high-order polynomial fitting, a fitted instantaneous frequency curve is obtained, and phase discrimination time marks are solved according to the fitted instantaneous frequency curve; thirdly, equal-angle resampling is performed on the original vibration signal to obtain an angular domain signal; and fourthly, Hilbert envelope demodulation is performed on the angular domain signal, an envelope order spectrum of the angular domain signal is solved, whether the rolling bearing has a fault or not and the fault type are judged by analyzing the envelope order spectrum, a diagnosis result is given, maintenance suggestions are proposed, and therefore normal running of a metro vehicle is guaranteed. Through the synchronous compression transformation order analysis method, instantaneous frequency conversion information contained in the vibration signal can be precisely extracted, order tracking is realized, a specific hardware device is not needed, the installing process is greatly simplified, and thefault monitoring cost is lowered.

Description

technical field [0001] The invention relates to the technical field of subway vehicles, in particular to a synchronous compression transformation order analysis method for fault diagnosis of rolling bearings. Background technique [0002] As an important part of the subway axle box, bearings play a vital role in the smooth operation of the subway. The vibration signals of rolling bearings running at variable speeds contain richer characteristic information than those at constant speeds. In recent years, order ratio analysis has been more and more used in the fault diagnosis of variable speed machinery. Its basic principle is to convert the unsteady time domain signal into a quasi-steady angle domain signal through equal angle resampling. [0003] At present, there are three types of order analysis techniques at home and abroad: hardware-based order tracking using phase detectors, calculated order tracking (COT), and rotating machinery order tracking based on instantaneous f...

AI Technical Summary

Problems solved by technology

The time-frequency resolution of STFT is not high, and it is susceptible to noise interference, which will affect the extraction of instantaneous frequency

WD Due to the existence of cross terms, it is difficult to extract the instantaneous frequency curve

WT cannot improve the aggregation of time and frequency, is susceptible to interference, and the accuracy of the extracted instantaneous frequency curve is not high

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