风洞虚拟飞行模型机与原型机动力学特性分析

在低速风洞虚拟飞行试验系统中，采用三自由度（3-DOF）球铰支撑动力学相似缩比飞机模型，在气动力矩作用下试验模型可绕质心自由转动。这种带约束的运动与具有六自由度（6-DOF）的真实大气飞行存在差别，鉴于此，对各影响因素逐个剖离并进行了数值模拟和对比分析。结果表明：位移约束使两者间的动力学特性产生较明显的差异，缩比的影响符合相似准则规律，机构摩擦、模型重心与支撑点不重合影响较小，常值干扰力矩对模型的初始响应有一定影响。对比分析结果可以用于指导风洞虚拟飞行试验的开展，并有助于完善风洞虚拟飞行试验技术及其拓展应用。

Analysis of dynamic characteristics between prototype aircraft and scaled-model of virtual flight test in wind tunnel

This paper presents a virtual flight testing system in low speed wind tunnel, which has a 3-degree-of-freedom (3-DOF) gimbal mechanism to connect a dynamically-scaled wind tunnel model supported by a vertical strut. The model can freely rotate around the center of gravity due to the aerodynamic moments. Obviously the constrained motion is different from the real 6-DOF free flight in the air. So the influencing factors which contribute to the dynamic characteristics' differences between the prototype aircraft and scaled-model are individually compared and investigated through flight dynamics simulation. The results demonstrate that the constrained translational movement has a significant impact on the dynamic characteristics while the dynamic response of the scaled-model and full-scale aircraft meets the similarity law; both the 3-DOF bearing friction and the non-coincidence between center of gravity and center of gimbal has small influence; the constant moment disturbance has some impact on the initial response. The comparison and analysis can provide a guide for the virtual flight test in wind tunnel, and are also helpful for the improvement and application of the wind tunnel testing technique.