Vibration signal analysis of a rotor-bearing system through wavelet transform and empirical mode decomposition

Abstract

Vibration analysis is widely used for the monitoring of the health of rotating machinery. There are different methods to interpret the vibration signals like time-domain analysis and frequency domain analysis, where the conventional Fast Fourier Transform (FFT) method is applied. FFT has been used successfully to extract stationary parameters from the frequency domain data. Complex machines normally consist of many parts and their vibration response contains many non-stationary signals and nonlinear signals. The objective of this research is to explore the feasibility of utilizing the wavelet transform (WT) and empirical mode decomposition (EMD) to efficiently decompose the sophisticated vibration signals of a rotor-bearing system into a finite number of intrinsic mode functions so that the fault characteristics of the rotor-bearing system can be analysed. A test rig of a rotor-bearing system was used to perform the experiments, and the vibration signals were recorded through NI-DAQ system. Vibration signals received from the test rig were analyzed using MATLAB software to present the useful information. The analysis result showed that the proposed approach is capable of diagnosing the faults of the rotor-bearing system.