基于短时傅里叶变换的飞行器故障振动信号分析

目的对某飞行器出现故障时的振动信号进行分析,为故障定位提供依据。方法将短时傅里叶变换方法应用于飞行振动信号分析,通过计算故障振动信号和正常振动信号的短时傅立叶变换谱,获取两者之间的不同时频特征。通过分析包括发动机工作、外部气动激励、设备工作、电气干扰在内的各种影响因素的时频变化特征,与故障振动信号的时频特征对比,为故障定位提供依据。结果故障振动信号的时频特征表现为飞行中期突发出现的某一频率的倍频振动响应,且振动频率随时间增加逐渐增大,分析表明只有发动机异常工作才具有此特征。结论短时傅里叶变换可以有效地获取飞行振动信号的时频特征,可以更深入地了解不同振动影响因素的时频特征,为飞行故障定位分析提供了新途径。

Fault Vibration Signal Analysis of Air Vehicle Flying Based on STFT

This paper analyzes the vibration signal of an aircraft in case of fault,and provides the basis for fault location.The STFT(Short Time Fourier Transform)method is applied to the analysis of flight vibration signals.By calculating the STFT spectrum of fault vibration signals and normal vibration signals,the different time-frequency characteristics between them are obtained.By analyzing the time-frequency characteristics of various influencing factors including engine operation,external pneumatic excitation,equipment operation and electrical interference,and comparing with the time-frequency characteristics of fault vibration signals,the basis for fault location is provided.The time-frequency characteristic of the fault vibration signal is the frequency doubled vibration response of a sudden frequency in the middle of flight,and the vibration frequency increases gradually with the increase of time.The analysis shows that only the abnormal operation of the engine has this characteristic.STFT can effectively obtain the time-frequency characteristics of flight vibration signals,and can better understand the time-frequency characteristics of different vibration influencing factors,which provides a new way for flight fault location analysis.