The Application Research of Direct Sifting EMD Based on Cubic B-Spline Interpolation Curve and Its Application in Processing Vibrating Signal of Machinery

摘要

In the classical EMD, calculating curve of mean of upper and lower cubic spline envelope curve decomposes original signal. But local mean cannot be substituted by envelope mean for non-linear and non-stationary signal. Otherwise, the method based on envelope mean can result in problem that the extremum overshoot and undershoot. The local mean interpolation curve of signal is directly calculated based on B-spline, which has good local property. This method conquers the shortcoming of classical EMD. The processing result manifests that the EMD based on local mean interpolation curve of B-spline is better than the EMD based on cubic spline by analyzing vibrating signal of rotating machinery. The intrinsic mode functions get by ameliorated EMD accord with real physical meaning of signal.