跪式起落架直升机地面平衡特性分析

Analysis of Ground Balancing Characteristics of Kneeling Landing Gear Helicopter

针对跪式起落架特殊的结构形式及其在地面载荷下呈现"下跪"姿态的运动特点,考虑缓冲支柱及轮胎的非线性特性及跪式起落架的非线性运动,对跪式起落架直升机地面平衡状态进行建模分析。首先,对跪式起落架进行力学分析,建立跪式起落架及全机纵向平衡方程;然后,通过调用Matlab中的Fsolve命令对建立的非线性方程组进行求解,得到了不同载重和不同拉力系数下,受重心运动、机体绕重心转动及桨盘倾斜角变化等多种非线性因素耦合影响的跪式起落架运动规律。跪式起落架直升机地面平衡特性的计算,对进一步计算跪式起落架直升机机体模态特性和"地面共振"分析具有十分重要的意义。

In light of the special structure of the kneeling landing gear and the movement characteristics of“kneeling posture”under the ground load,considering the nonlinearity of the buffer,tire and the kneeling landing gear motion,the ground balancing state of the kneeling landing gear helicopter was modeled and analyzed.Frist,the kneeling landing gear was analyzed with mechanics,the longitudinal balance equations of the kneeling landing gear and the whole helicopter was built.Then,the nonlinear equations were solved by invoking Fsolve command in Matlab and the motion rules of kneeling landing gear under different load and different rotor thrust coefficient were obtained,which was influenced by many nonlinear factors such as the motion of the center of gravity,the rotation of the body around the center of gravity and the change of the angle of rotor disk.