减速器振动信号的经验模态分解

时域同步平均是直升机减速器诊断技术的基础,目前这种方法依赖于转速传感器提供相位同步信号。探讨了应用经验模态分解代替时域同步平均分析减速器振动信号的方法。构建了一个减速器振动信号模型,提取了故障特征信号。对经验模态分解过程进行了理论推导,证明经验模态分解可以分离出故障特征信号,给出了信号分离的充分条件。将这种方法应用于直升机减速器的两种故障(点蚀和裂纹)振动数据,结果表明经验模态分解正确地分离出了故障特征信号,信号特征更为显著。

Research on Empirical Mode Decomposition of Gearbox Vibration Signal

Time synchronous averaging of vibration data is a fundament technique for helicopter gearbox diagnosis.Currently,this technique relies on hardware tachometer to give phase synchronous information. Empirical Mode Decomposition (EMD) is introduced to replace time synchronous averaging of gearbox vibration signal. A simple model of gearbox vibration signal is established and the characteristic vibration signals are extrated.The process of EMD is theoretical expressed under this condition, from which it is proved that different characteristic signals could be separated under a sufficient condition. The method is validated by experimental vibration data from recordings of a helicopter intermediate gearbox with fatigue pitting or cracking. The results show that EMD separates exactly the characteristic signals, which are more reliable in diagnosis of gear faults.