跨大气层飞行器气动伺服弹性稳定性分析方法研究

跨大气层飞行器通常采用翼身组合体外形,机体结构柔性大,飞行控制系统通道之间交联耦合且通频带宽、再入扰动因素复杂、气动加热严重,上述因素可能导致气动伺服弹性或热气动伺服弹性问题。考虑外界干扰不确定性、飞行器模型摄动和控制通道耦合等因素,跨大气层飞行器需进行多通道交联耦合气动伺服弹性鲁棒稳定性分析。通过弹性飞行器动力学建模、非定常气动力拟合、伺服系统和飞行控制系统建模,建立了气动伺服弹性系统的闭环模型。在此基础上对Nyquist方法、最小奇异值法以及结构奇异值μ方法等气动伺服弹性稳定性分析方法进行了分析与讨论,得出相关结论。

Research on Methodology of Aeroservo-elastic Stability Analysis for Trans-atmospheric Vehicle

Using wing-body configuration and big lifting surface and control surface, trans-atmospheric vehicle usually has low overall structure stiffness and wide-band multi-way cross-linked flight control system, and must withstand complex flight environment and serve aerodynamic heating during reentry. Factors above may easily induce aeroservo-elastic stability problems. Due to external disturbance, vehicle model perturbation and coupling of control channels, robustic aeroservo-elastic stability analysis must be applied to trans-atmospheric vehicle. In this paper, motion equations of flexible flight vehicle are deduced by using Lagrangian method considering coupling between rigid-body modes and elastic vibration modes. State-space model of closed-loop aeroservo-elastic system is established based on rational function approximation of unsteady aerodynamics and modeling of servosystem and flight control system. Furthermore, nyquist criteria, the minimal singular value theory and the structured singular value analysis are studied for aeroservo-elastic stability analysis, and some conclusions are drawn consequently.