高空长航时无人飞机多采用大展弦比布局，存在结构几何非线性，其气动弹性问题是一个飞行动力学、结构动力学与空气动力学耦合问题，需要把气动弹性分析和飞行动力学分析统一起来进行整体分析。本文针对这一问题进行研究，提出了一种非线性气动弹性和飞行力学耦合分析的多体动力学方法，主要内容包括：1. 基于多体动力学提出了柔性飞机气动弹性系统建模的方法，该方法利用多体动力学方法描述柔性飞机系统，利用片条理论与ONERA气动力模型相结合的方法来描述气动力，并利用反馈控制考虑飞行控制和颤振系统，综合多体动力学方程、ONERA方程以及控制状态方程，得到气动弹性系统控制方程，为非线性气动弹性和飞行力学的统一分析提供了一种途径。该方法把飞行动力学与控制问题和气动弹性问题放在一个框架下，研究飞机在飞行过程中的气动弹性行为，能描述飞机中的复杂约束，抓住飞机这一复杂系统的真实物理机制。2. 提出了通过施加姿态和推力控制进行柔性飞机配平的动力松弛方法，该方法可以直接通过多体动力学时域求解获得柔性飞机配平条件。然后，从气动弹性系统控制方程出发，推导了基于平衡位置附近的线性扰动方程，并通过特征值求解进行气动弹性稳定性分析。利用该方法可以判断颤振临界速度，并可以在超出颤振边界情况下通过求解模态阻尼识别出结构失稳模态。3. 利用所提出的方法对悬臂机翼模型进行了气动弹性分析，通过在平衡位置的稳定性分析，确定颤振临界速度，并求解了系统的极限环响应，通过识别系统的模态阻尼确定失稳模态，并研究了折叠铰间隙对折叠翼气动弹性特性的影响。4. 把所提出的方法用于整机模型的气动弹性分析，基于刚化飞机模型设计了柔性飞机的飞行控制律，求解了极限环响应，通过上述数值仿真发现，柔性飞机首先进入含机身滚转的反对称颤振模式，并找到利用姿态和颤振协同控制抑制反对称模式主导的颤振的方法。由于多体动力学方法在描述大位移大转动问题上具有优势，容易实现对柔性飞机飞行机动的仿真与控制。选取包括盘旋、筋斗、俯冲-筋斗-跃升、尾冲等机动，对柔性飞机的气动弹性行为进行了研究。

High-Altitude Long-Endurance (HALE) unmanned aircraft is usually given large aspect ratio in design, which contains structure geometrical nonlinearity. The aeroelasticity of its wing is a coupling problem of flight dynamics and structural dynamics of aircraft, which need to be studied by considering nonlinear aeroelasticity and flight dynamic behavior integrally. To solve this problem, the main work of this dissertation is summarized as follows:1. An modeling approach of aeroelastic system of aircraft is presented based on multibody dynamics. The aircraft is modeled as a multibody system considering the flexibility of wings. The ONERA aerodynamic stall model is used to evaluate the aerodynamic forces by combining the strip theory. Feedback controls are embedded into the aircraft model. The governing dynamic equations of aircraft are established by combining multibody dynamic equation, ONERA equation, and state equation of feedback control. The numerical integrate scheme is given for solving the governing equation based on backward differentiation formulas. The aeroelasticity, flight dynamics and control are considered under one theoretical framework in this approach, through which the aeroelastic behavior of aircraft in flight can be studied, and the mechanism such as joints or gaps can be easily included and analyzed to capture the nature of such complex structure as aircraft.2. A trimming method in the manner of dynamic relaxation is presented under the attitude and throttle controls, by which the trim condition can be obtained by solving the governing dynamic equations in time domain. Around the trim state, the perturbation equations are derived for analyzing the stability of aeroelastic system, in which the flutter critical velocity can be determined and the unstable mode of system can be identified by solving the modal damping.3. Using the presented method, the aeroelastic characteristic of the wing model is studied by this approach. By analyzing the stability at the trim state of system, flutter critical velocity can be determined. Beyond the flutter boundary, the limit cycle oscillations response is solved. The unstable mode of system can be identified by solving the modal damping. The impact of hinges with gap on the aeroelasticity of the folding wing model is studied.4. Through the proposed approach, the aeroelastic behavior of the whole aircraft is studied under the attitude control and throttle control. The limit cycle oscillations response is solved, then the coupling dynamic behavior of flutter and flight of the flexible aircraft is studied, in which the interesting aspect of the anti-symmetric flutter mode involving the roll motion of the fuselage is found, and finally, the joint control of flutter and attitude is used to suppress the limit cycle response and to stabilize the attitude of aircraft. Because multibody dynamics has advantages in modeling of flexible bodies that undergo large displacements and large rotations, it is convenient to realize the simulation and control of the flight maneuvers of flexible aircraft. This approach is utilized to study the aeroelastic behavior of aircraft in the flight maneuvers such as circling, loop, dive-loop-climb, and tail-slide.