Designing the technology of express diagnostics of electric train's traction drive by means of fractal analysis

Abstract

EN: The object of this study was the development of technology of the express diagnostics of the traction drives of electric trains. Its base was obtaining, processing and fractal analysis of vibroacoustic signals, which makes it possible to forecast the period of service of this unit in between planned maintenance works. We carried out the research into the failures of equipment of electric trains in operation, which showed that the share of defects in the traction reducers is the most significant and amounts to 41,2 % of the total number of failures in the carriage part. The method of selection of acoustic components (samples) was created, which makes it possible to separate them from the complete vibroacoustic signal. Its characteristic peculiarity is initial link to the time interval, determining final duration, as well as selection of a number of cyclically repeated components with each rotation of the large gear of the traction drive. Based on the wavelet conversion of detailing coefficients with high content of noise components, we used the method of denoising vibroacoustic samples with the help of soft thresholding. As the diagnostic parameter, the fractal Hurst index is proposed. The process of its determining is described and the maximum ranges of its change from the point of view of persistence are found.

UA: Предметом дослідження є розробка технології експрес діагностування тягових передач електропоїздів. У її основу покладені оригінальні підходи щодо фрактального аналізу віброакустичних сигналів. Створено метод виділення акустичних складових (сэмплів), а також очистка їх від шуму. Як діагностичний параметр запропонований фрактальний показник Херста. Визначені діапазони його зміни. Це дозволяє оцінювати технічний стан тягових передач і прогнозувати їх працездатність в експлуатації.