Construction of redundant lifting scheme multi-wavelet packets and its application

Key words:  lifting scheme multi-wavelet packets  redundant algorithm  singular value decomposition  fault diagnosis

Abstract:

Aiming at the extraction of weak period impact components buried in original signal, a novel method to combine redundant lifting scheme multi-wavelet packets(RLSMWP) and sliding window singular value decomposition(SWSVD) was developed. Original signal was pre-filtered by redundant Haar preprocessing with five approximation order, and vector signal was calculated. The vector approximation signal was calculated by redundant updater and rescaled and decomposed furthermore.The redundant lifting scheme multi-wavelet packet transform was realized. Every output channel signal on the last level was denoised using SWSVD, then signal was reconstructed using reconstruction algorithm. The results show that the noise reduction effect is good using RLSMWP-SWSVD method, and the weak fault signal of a valve was extracted from the strong vibration background. Compared with the traditional multi-wavelet construction algorithm, the new method achieves prefiltering, multi-wavelet decomposition, multi-wavelet reconstruction and post-processing in the time domain. The new method is characterized by simple calculation and high computing speed. It can save memory and can be completely reconstructed.