基于改进EMD的旋转机械耦合故障诊断方法研究

Study on Coupling Faults of Rotary Machinery Diagnosis Method Based on Improved EMD

提出一种基于改进EMD的旋转机械耦合故障诊断方法。该方法结合相似极值延拓和加余弦窗函数运算的优点,解决了延拓部分不精确和加窗函数后使原信号发生改变的问题,提高了EMD方法的运算精度。应用该方法对存在裂纹碰摩故障的转子-轴承系统振动信号进行了特征提取,并进行了故障诊断,与单一故障特性相比,诊断出的振动信号既有裂纹引起的高频成分,也有碰摩引起的低频成分,得到的耦合故障特征证明了该方法的有效性。

A method of coupling faults diagnosis on rotary machinery based on improved EMD was proposed. The method which combined advantages of similar extrema extension and cosine win- dow function, solved the problems that continuation parts were not accurate and the original signal changed because of adding window function, and improved the operation precision of EMD method. Vibrating signal feature extraction and fault diagnosis were studied on rotor--bearing system with coupling faults of crack and rub--impact by the method. The vibrating signals from rotor disk of fault system were diagnosed with both high--frequency components due to crack and low--frequency com- ponents due to rub--impact, and the coupling fault features were acquired. It is proved the method is effective.