An improved method to solve the end effect of EMD and its application on vibration signal

In order to solve the problem of end effect in empirical mode decomposition (EMD), A new method of data extending based on minimum similarity distance is proposed. Firstly, the formulas of matching distance and waveform similarity coefficient are given, and then according to some matching rules, the extending data series which has the optimality minimum similarity distance compared with the ends are derived from the inner signal. The paper considers two factors synthetically, waveform and amplitude, makes the matching waveform more accord with the nature tendency of the signal, realizes the smooth transition between extending data and original signal. This new method is applied to drill string vibration signal analysis, and simulation results show that this method is effective to restrain the end effect of EMD method.