【作者】 王倩；

【导师】 艾剑良；

【作者基本信息】 复旦大学 ， 流体力学， 2011， 博士

【摘要】 高超声速飞行器已经成为世界航空航天领域一个极其重要的发展方向,其中高超声速飞行器的控制技术是高超声速飞行器研究的重点及难点,也是世界各国研究的热点。与常规飞行器相比,高超声速飞行器采用的是机身/发动机一体化技术,从而使得高超声速飞行器的推进系统与结构动态之间存在强耦合,其模型呈现出高度的非线性特征,并且模型还存在有大量的不确定气动参数。此外,高超声速飞行器在大马赫数和高海拔的条件下飞行,外界扰动和未知因素的扰动十分显著,从而影响了飞行的稳定性。这些因素给高超声速飞行器模型的确定和控制系统的设计带来了前所未有的挑战。本文以国外已公开的通用高超声速飞行器纵向模型为研究对象,进行相关的控制方法研究。为了掌握高超声速飞行器复杂的气动特性,首先进行了高超声速飞行器全状态非线性六自由度建模,建立了研究对象的被控数学模型,并分析了发动机模型。然后结合某一高超声速飞行器(Winged-cone)的外形设计,采用数值模拟的方法,计算出高超声速飞行器在不同飞行条件下的气动参数。在此基础上,研究了高超声速飞行器的气动特性。并对高超声速飞行器全状态运动方程进行解耦分析,得到了高超声速飞行器纵向运动方程,对其进行特征值分析和动态响应分析,从而更加深入的了解了高超声速飞行器不同于常规飞行器的气动特性和飞行特点,也为接下来控制系统的设计提供了适当的控制平台。针对高超声速飞行器强耦合非线性的纵向模型,采用反馈线性化方法将高超声速飞行器纵向模型进行输入/输出精确线性化,然后以此为基础,设计出以二次型最优控制器作为辅助控制器的动态逆控制系统,该系统不仅能够解除高超声速飞行器纵向模型输入/输出之间的强耦合,还可以保证高超声速飞行器对指令信号跟踪的精确性和飞行过程的稳定性。并结合Matlab的仿真工具Simulink,对所设计的控制系统进行仿真,验证了高超声速飞行器动态逆控制系统良好的控制性能。关于高超声速飞行器不确定性因素的影响,且不确定性与控制输入处在同一通道内,采用滑模控制技术来设计高超声速飞行器飞行控制系统,解决了高超声速飞行器在实际飞行过程中,因模型的不确定性因素所产生的控制问题,提高了控制系统的鲁棒性能；并且设计出了一个非线性滑模观测器来估计攻角及航迹倾角等难以测量的状态,从而满足了所设计的滑模控制系统需全状态反馈的要求,仿真验证了高超声速飞行器滑模观测器的鲁棒性。对于高超声速飞行器不确定因素不能直接被控制作用所抵消的控制问题,即不确定因素与控制输入不处在同一通道内,采用动态面控制方法来设计高超声速飞行器飞行控制系统。该控制系统可以抑制飞行过程中因参数和结构变化所引起的不确定性的扰动,扩大了控制系统的适用范围,可以满足高超声速飞行器在更为复杂的环境下飞行的控制要求。仿真验证了该方法的有效性。综上所述,本文对高超声速飞行器飞行控制方法进行了深入的研究。针对其不稳定的、严重非线性的、输入输出强耦合的数学模型以及结构和参数不确定性等特点,对控制方法进行了详细的研究讨论,并通过仿真验证了所采用的各种控制方法的有效性,得出了有益的结论。更多还原

【Abstract】 The hypersonic vehicles have become a very important direction in the fields of aeronautics and astronautics around the world. And the flight control technology of the hypersonic vehicles is a main and difficult point, besides it is a hotspot in the research of all the countries. Compared with general vehicles, the hypersonic vehicles adopt the engine-airframe integration technology, which results in strong coupling between propulsion system and structural dynamics, and brings highly nonlinear characteristics to the hypersonic vehicle models, in which there are also many uncertain aerodynamic parameters. Furthermore, the hypersonic vehicles are flying in the conditions of high altitudes and Mach numbers, the perturbations from the environment and uncertainties are obvious, so the flight stability of the hypersonic vehicles is influenced. All the factors mentioned have brought great challenges to the model confirming and control system designing of the hypersonic vehicles. In this paper, the related control research is carried out based on the generic hypersonic vehicle longitudinal model published overseas.In order to grasp the hypersonic vehicles’complex aerodynamic characteristics, firstly, the full-state, nonlinear and 6-freedom motion differential equations of the hypersonic vehicle model are established. And the engine model is analyzed.Secondly, the numerical method is adopted to estimate aerodynamic coefficients of the hypersonic vehicles in different flight conditions. By analyzing the results, the aerodynamic characteristics are understood. And the longitudinal dynamics equations are obtained by decoupling analysis. Eigenvalue and dynamic response of the longitudinal dynamics equations are studied to deeply know the particularities of the hypersonic vehicles. And it is possible to provide an appropriate control object to flight control system designing for the hypersonic vehicle.For the strong coupled and highly nonlinear hypersonic vehicle longitudinal model, feedback linearization method is utilized to make the longitudinal model output/input exact linearization. And based on it, the dynamic inversion control system is designed combining with the linear quadratic controller. The control system designed not only can decouple the output and input of the longitudinal model, but also can ensure the veracity of commands tracking and flight stability. Numerical simulation is done via MATLAB/SIMULINK to verify the good performance of control system designed. For the hypersonic vehicle uncertainties, sliding model control technology is used to design flight control system of the hypersonic vehicle. And it solves the control problems brought by the imprecise mathematical model, enhances the robust performance of the control system. Numerical simulation is done to verify the robust and control performance of the sliding mode control system designed. Also a sliding mode observer is designed to estimate difficultly measured states, which can satisfy the full-state feedback requested by sliding mode control system. Numerical simulation is done to verify the robust performance of the hypersonic vehicle sliding mode observer designed.For the hypersonic vehicle uncertainties, which are not counteracted by control effects, the dynamic surface control method is adopted. It can restrain the uncertain perturbations brought by the changes of parameters and structure. It enlarges the applied range of control system, and it can satisfy control request when the flight condition is more complex. Numerical simulation is done to verify the availability of the control system designed.Above all, the flight control methods of the hypersonic vehicles are deeply studied in this paper. For unstable, highly nonlinear and strong coupled mathematic model and structural and parameters uncertainties, the control methods are detailed discussed. Numerical simulations show the validity of every control method, and useful results are found.更多还原