Multi-source and Multi-fault Condition Monitoring Based on Parallel Factor Analysis and Sequential Probability Ratio Test

Abstract

The monitoring of mechanical equipment systems contains an increasing number of complex content, expanding from traditional time and frequency information to three-dimensional data of the time, space and frequency information, and even higher-dimensional data containing subjects , experimental conditions. For high-dimensional data analysis, traditional decomposition methods such as Hilbert Transform, Fast Fourier Transformation and Gabor transformation not only lose the integrity of the data, but also increase the amount of calculation and introduce a lot of redundant information. The phenomenon of feature coupling, aliasing and redundancy between the mechanical multi-source data signals will cause the inaccuracy of the evaluation, diagnosis and prediction of industrial production operation status. The analysis of the three-way tensor composed of channel, frequency and time is called Parallel Factor Analysis (PARAFAC). The properties between the parallel factor analysis results and the input signals are studied through simulation experiments. Parallel factor analysis is used to decompose the third-order tensor composed of channel-time-frequency after continuous wavelet transformation of vibration signal into channel, time and frequency characteristics. Multi-scale parallel factor analysis successfully extracted nonlinear multi-dimensional dynamic fault characteristics by generating the spatial, spectral, time-domain signal loading value and three-dimensional fault characteristic expression. In order to verify the effectiveness of the space, frequency and time domain signal loading values of the fault characteristic factors generated by the centrifugal pump system after parallel factor analysis, the characteristic factors obtained after parallel factor analysis are used as the SPRT test sequence for identification and verification. The results indicate that the method proposed in this article improves the measurement accuracy and intelligence of mechanical fault detection.