To a helicopter , one of the key technologies is how to control the airscrew . so it is very important to simulate aerodynamic loads acting on the helicopter ' s airscrew when the helicopter is flying in the air . it affords datum , which are contributed to the use of new flight vehicle 对于直升机来说，旋翼操纵控制是其关键技术之一，对旋翼进行地面加载试验，模拟旋翼在飞行过程中所受的气动载荷，对于研究和改进直升机飞行控制系统非常重要。
Electro - hydraulic servo loading system ( ehsls ) is an important simulation system in hardware - in - loop flight simulation laboratory , which can simulate aerodynamic loads acting on flight vehicle , such as missiles , planes . it is one of most important devices in the whole flight vehicle simulation system 电液伺服加载系统是半实物仿真实验室中模拟导弹等飞行器在飞行中舵面所受空气动力载荷的重要设备，它是飞行器大回路半实物仿真系统的重要组成部分。
Included three positions system , the helicopter airscrew electro - hydraulic servo loading system has coupling nexus of three positions and three loadings . trough analyzing nexus of the displacement and the force , this paper designs the three channels electro - hydraulic servo loading system basing on the analysis of single channel electro - hydraulic servo loading system . surplus torque , which is produced through position disturbance , is a chief problem facing aerodynamic loading system 直升机旋翼的操控通过三个助力器完成，模拟负载时把旋翼所受空气动力折算到了三个助力器上，由于三个助力器是铰点在一个模拟盘上，所以三通道加载系统与三个助力器位置系统有一定的耦合关系。
In addition , aerodynamic stiffness and aerodynamic damping on the system are already obtained in the condition of fluid - structure interaction . it is known that aerodynamic loads are associated with blade vibration . the systematic eigenvalues are used to judge whether the flutter occurs so as to find the stable operating range of a wind turbine 本文把风力机叶片简化为悬臂梁，对梁截面的二维叶型建模，完整推导了二维叶型的线性运动微分方程和流构耦合条件下系统的气动刚度和气动阻尼，此时气动载荷与结构的位移矢量以及速度矢量是相互耦合的，再利用系统的特征值来判断叶片颤振是否发生，从而获得风机的稳定工作范围。
Using the engineering methods of supersonic and hypersonic flow or local piston theory developed in this paper to compute unsteady aerodynamic loads , and coupling structural equations , the supersonic or hypersonic aeroelasticity with a typical servo system under thermal environment is simulated in time - domain 运用超音速、高超音速气动力工程计算方法和本文发展的当地流活塞理论计算非定常气动力，耦合结构运动方程，实现了热环境中带有伺服机构的气动弹性的时域仿真。
