采用多桨叶坐标转换和复数坐标 变换等方法，研究了变距/摆振耦合对直升 机空中共振的影响；推导出完全引入变距/ 摆振耦合的直升机空中共振分析公式，建立 了相应的分析模型和计算程序。利用系统的 特征值研究了直升机空中共振的动不稳定性， 得出变距/摆振耦合对直升机空中共振的影响 ；通过系统的特征向量与各自由度之间的相互 作用（能量关系）的研究，揭示了空中共振机理 ，以某型直升机为例进行了计算分析。研究表明 ：正的变距/摆振耦合可以抑制旋翼/机体耦合 系统的动不稳定性，在同时存在挥舞/摆振耦合 和正的变距/摆振耦合时，直升机的旋翼/机体 耦合系统为绝对稳定。

The influence of pitch/lag coupling on helicopter air resonance is investigated by the methods of multi- blade coordinates transformation and complex coordinates transfer in this paper.  First,  helicopter air resonance equations of motion considering pitch/lag coupling is derived,  related analysis model and calculation programs are built to study the effect of pitch/lag coupling on helicopter air resonance through the eigenvalue of the system.  Second,  through the eigenvector and the analysis of the approximate expression of mutual excitation of different degrees of freedom,  the explanations of the helicopter air resonance considering pitch/lag coupling are explicated.  The results indicated that the positive pitch/lag coupling can restrain the instability of helicopter rotor/body coupling system and the system becomes strongly stabilized in the case of considering flap/lag structure coupling and pitch/lag coupling together.