基于DTCWPT和奇异值差分谱的万向轴动不平衡检测方法研究

针对万向轴动不平衡振动信号复杂、提取故障特征难度大等问题,提出了基于双树复小波包(Dual Tree Complex Wavelet Packet Transform,DTCWPT)和奇异值差分谱的动不平衡检测方法。首先采用DTCWPT将万向轴振动信号分解为不同频段的分量,对包含万向轴特征信号的频段构造Hankel矩阵;然后计算奇异值差分谱,以差分谱前五个最大突变点确定奇异值重构个数进行重构;最后求傅里叶谱提取万向轴特征频率幅值。通过线路试验数据对该方法进行验证并分析动不平衡值和万向轴转动频率幅值、运行速度间的关系,结果表明:该方法能够有效凸显万向轴动不平衡特征频率,提高谱线清晰度。转频幅值与动不平衡值呈正相关,动不平衡值增大,转频幅值增大;动不平衡值一致,万向轴转频幅值随运行速度增加而增大。

Research on the Detection Method of the Dynamic Imbalance of Cardan Shaft Based on DTCWPT and Singular Value Difference Spectrum

For the complex of the vibration signal in cardan shaft with dynamic imbalance and the difficulty to extract the fault feature, a new method was proposed based on dual-tree complex wavelet packet transform (DTCWPT)and singular value difference spectrum. Firstly, the vibration signal was decomposed through DTCWPT to get the different frequency band components. A Hankel matrix was constructed of the component which contains the cardan shaft characteristic signal. Secondly, to calculate the difference spectrum through single value difference. With the top five catastrophe values of the difference spectrum to determine the key singular values and reconstruct the vibration signal. Finally, the fourier spectrum of the reconstructed signal was applied to extract the amplitude of characteristic frequency. The method was verified by test data, and using the method to analysis the correlation of dynamic imbalance of cardan shaft with high-speed train running speed and the amplitude of characteristic frequency. The results show that themethodcan highlight the dynamic imbalance characteristics of cardan shaft and improve the spectral lines of clarity. Dynamic imbalance value is positively related to the amplitude of characteristic frequency. With the dynamic imbalance value increases, the amplitude increases. And the dynamic imbalance value remains unchanged, the amplitude of rotational frequency is increased with the raise of running speed.