EMD based envelope analysis for bearing faults detection

The envelope analysis technique, used for many years in faults detection of bearing by vibration analysis, is combined with the technique of empirical mode decomposition (EMD), which has been applied to non-stationary and non-linear signal analysis. The method to fault diagnosis of bearing based on EMD and envelope spectrum is presented. The methodology developed in this paper decomposes the original times series data in intrinsic oscillation modes, using the empirical mode decomposition. Then the envelope spectrum is applied to the selected intrinsic mode function (IMF) which stands for the bearing faults. The techniques are demonstrated by the experiments on a machine tool with a ball bearing under simulated crack on the inner race or outer race. The experimental results show that this method based on EMD and envelope spectrum can effectively diagnosis the faults of bearing.