基于双树复小波变换的转静碰摩响应分析

摘要

The de-noising of rub-impact response signals of a rotor-stator system and its characteristics extraction are key problems of rub fault diagnosis.A piecewise smooth threshold function was constructed for wavelet de-noising,and non-stationary signals were de-noised separately by using Wavelet,Wavelet packets and dual-tree complex wavelet transform(DTCWT).SNR (signal to noise ratio)was taken as an index to evaluate the de-noising effect.The results reveal that the constructed threshold function is highly active in de-noising.As an example,the dynamic response of a single rotor under rub-impact was calculated and decomposed by DTCWT.The simulation and experiment results show that the dynamic response can be exactly derived due to the complementary property between approximate analyticity and sampling interpolation of DTCWT.It is also proved that the proposed method is effective.%针对碰摩故障诊断中转静碰摩响应消噪及特征提取构造分段圆弧平滑阈值函数，利用小波、小波包及双树复小波（Dual-tree Complex Wavelet）分别对非平稳信号降噪处理，以信噪比为指标判断降噪效果。结果表明，构造的阈值函数消噪具有高效性。通过计算单转子局部碰摩动态响应，用双树复小波对位移响应进行特征提取。与小波及小波包相比，双树实小波近似解析性及采样插值具有互补特点，能完整提取动态响应特征，减少信息丢失。并用仿真及转子碰摩实验验证该方法的有效性。