基于Lyapunov指数能谱分布的转子-机匣系统故障诊断研究

FAULT DIAGNOSIS RESEARCH WITH REGARD TO ROTOR-CASE SYSTEM BASED ON LYAPUNOV EXPONENT ENERGY SPECTRUM

提出了基于Lyapunov指数能谱分布的航空发动机转子-机匣系统故障诊断新方法。基于相空间重构,在优选重构参数的基础上,计算得到了某型航空发动机不同故障状态下机匣实测振动信号时间序列的Lyapunov指数谱;提出并定义了Lyapunov指数能、Lyapunov指数能谱、Lyapunov指数能谱分布的概念,获得了某型航空发动机在不同故障状态下的机匣实测振动信号时间序列的Lyapunov指数能谱及其分布,并基于此Lyapunov指数能谱分布对航空发动机转子-机匣系统进行了故障诊断和状态识别。研究结果表明:航空发动机机匣振动时间序列在不同状态下具有不同的Lya-punov指数能谱及其分布,即可以Lyapunov指数能谱及其分布作为识别其状态的特征量,为航空发动机转子-机匣系统的故障诊断和状态监控提供了新的可靠的方法。

A new method for fault diagnosis of aero engine rotor-case system was proposed based on the Lyapunov exponent energy spectrum distribution. By virtue of the reconstruction of phase space and the optimization of reconstruction parameters such as the embedding dimension and the interval of delay time, the Lyapunov exponent spectrum of the experimental vibration time series of aero engine rotor-case system was calculated, which was measured on the aero engine pedestal at different working states or fault states. The concepts and the algorithms for the Lyapunov exponent energy, its spectrum and its spectrum distribution were defined and presented, then the spectrum distributions under different fault conditions were obtained, and accordingly, the fault conditions of the aero engine rotor-case system were detected. Research shows that the Lyapunov exponent energy spectrum distribution of the vibration time series of aero engine rotor-case system varies with the fault condition of the aero engine, that is to say it can be used as the characteristic measure for aero engine's fault diagnosis. The method offers a new reliable means for aero engine's fault diagnosis, condition monitoring and control.