【摘要】 旋翼系统是直升机的关键部件,一旦发生动不平衡故障,可能会使直升机大量动部件产生高周疲劳,导致机械故障,甚至引发飞行事故。首先针对双跷跷板结构四旋翼无人直升机旋翼不平衡故障自身振动信号的特点和其小波基函数的特性,从信号重构能力和相关性理论的角度,确定小波分解的最优小波基函数dbN系列;同时,基于最优小波基函数db5和强制阈值降噪的思想对监测的振动信号进行强制降噪;最后,运用小波包分解重构提取表征故障信息的前8阶小波包能量谱特征向量,提取的特征向量具有较好的区分性,为后续的故障诊断模式识别提供数据基础。更多还原

【Abstract】 As key component of a helicopter,once rotor unbalance fault occurs in the rotor system,high cycle fatigue of a large number of moving parts of the helicopter maybe happen,which will cause mechanical default,and even flight accident.Regarding the rotor unbalance fault of 2-seesaw unmanned helicopter,with the basis of signals’ characteristics and wavelet basis function’s features,firstly,the optimal wavelet basis function dbN was determined by signal reconstruction ability and the correlation theory.At the same time,based on the optimal wavelet basis function db5 and the theory of forced threshold denoising,the vibration signal monitored was denoised.At last,the first 8 orders wavelet packet energy spectrum characteristics of fault information which is distinctive,are extracted through wavelet packet decomposition reconstruction.It provided data basis for fault diagnosis of and pattern recognition.更多还原