Feature extraction of mixed faults of intershaft bearing based on homologous information and Hjorth parameters

Abstract

To make correct judgment on the mixed faults of intershaft bearing of aeroplane engine, the paper has proposed a feature option method. This method works by decomposing cross-correlation function (CCF) of homogeneous information from casing with intrinsic time scale decomposition (ITD) for the separation and blending of signals. Furthermore, option of proper rotation components (PRCs) for fault identification is made by abandoning the PRC related with the least Complexity parameter in Hjorth parameters. Moreover, signal is reconstructed based on the autocorrelation function (AF) of residual PRCs. Finally, according to the frequency spectrum of signal reconstructed, fault features corresponding to intershaft bearing are extracted and fault types estimated. The result indicates that the Complexity parameter in Hjorth parameter can be used as an evaluation index to implement the selecting of sensitive fault components. Furthermore, the mixed fault types which come from intershaft bearing of aeroplane engine could be judged correctly.