气动弹性影响下高超声速飞行器动力学建模与分析

高超声速飞行器通常采用轻质材料和细长升力体设计,导致受控刚体运动频率与结构振动频率趋于接近,给飞行器制导控制系统设计带来了巨大挑战。基于假设模态下建立了考虑变截面效应的高超声速飞行器自由梁结构动力学模型,对比了横截面梁和变截面梁模态振型和频率;考虑变截面效应后,振型变化较大,同时二、三阶模态频率均变小。给出了耦合气动弹性和飞行动力学的高超声速飞行器运动方程。在典型工况下,对比分析了刚体、常截面梁和变截面梁高超声速飞行器的平衡和动态特征,结果说明:变截面梁在平衡状态下附加攻角更大,系统在平衡点处开环不稳定性更大,同时非最小相位行为基本不变。

Modelling and analysis of a hypersonic vehicle with aeroelastic effect

Hypersonic vehicle can be designed into blended lift body by using light-weighted materials, which leads to close frequencies between controlled rigid-body motion and the oscillation of the structure. It brings about a huge challenge in the design of guidance and control system. Based on the assumed mode method, the free-free beam structural dynamics model considering variable cross-section effect was built. After comparing the mode shape and frequencies between cross-section and variable cross-section beam, it is found that the later one had a bigger mode shape change, and the frequency of second and three order both decreased. Given the hypersonic vehicle equations, the static and dynamic characteristics of constant cross-section and variable cross-section beam were analyzed in a typical condition. The results indicate that the variable cross-section beam has a larger appended angle of attack, the system is open-loop unstable, and exhibits non-minimum phase behavior in the trim condition.