Application of cyclo-non-stationary indicators for bearing health monitoring under varying operating conditions

摘要

During the last decades, an emerging interest has been reported on modelling rotating machinery signals as cyclostationary. Several tools, such as the Spectral Correlation Density (SCD) and the Cyclic Modulation Spectrum (CMS) have been proposed, assuming constant or almost constant rotating speed. To overcome this limitation, generalizations of SCD and CMS have been proposed that display cyclic Order versus Frequency. The goal of this paper is to propose a novel approach for the analysis of "cyclo-non-stationary" signals based on the generalization of indicators of cyclostationarity in order to cover the speed varying conditions, introducing a new speed-dependent angle averaging operator. The proposed Indicators of Cyclo-Non-Stationarity (ICNS) summarize the information at various statistical orders and at lower computational cost compared to the Order-Frequency SCD or CMS. The effectiveness of ICNS is investigated on a synthesized CNS signal and on acceleration signals captured on a damaged bearing operating under speed varying conditions.