高超声速飞行器气动弹性建模与鲁棒变增益控制

发布时间：2018-08-21 08:55

【摘要】：高超声速飞行器由于其在民用和军事领域都具有广阔的应用前景,得到了世界各军事强国的广泛重视,成为目前航空航天飞行技术的主要研究方向。高马赫数使得高超声速飞行器相对比常规飞行器具有了巨大的优势,同时也带来了许多技术挑战。只从控制科学角度来看,这些挑战主要包括气动／弹性／控制系统之间的耦合、机体／发动机之间的耦合、大跨度飞行导致的系统参数剧烈变化、控制舵面效率低下以及闭环系统始终处于近乎临界稳定状态等。本文以高超声速飞行器气动弹性问题为研究核心,针对当前气动弹性分析与面向控制的模型方面存在的问题,按照分析问题、建立模型、间题的提出、控制方法、控制器设计与综合的研究思路,分析了高超声速飞行器所受的气动力和弹性形变以及二者之间的关系,通过引入全新变量建立了飞行器的非线性运动模型,并且针对不确定性和参数变化问题分别给出了相应的控制算法,给出了完整的控制器设计与综合方法,保证飞行器在巡航和大跨度飞行过程中的姿态稳定。分析了X-43A构型的高超声速飞行器在高超声速流中机体表面的气流分区特性,给出了机体各表面气流特性与高度、速度以及攻角的关系；使用当地流活塞理论分析机体各表面和舵面上下表面的非定常气动力,给出了飞行器飞行中受到的合力和合力矩,为后续的分析气动与弹性的关系、建立高超声速飞行器以及飞行控制系统设计等工作建立了基础。分析了高超声速飞行器的自由振动和静态弹性形变,给出了飞行器在机体各表面气动力的作用下机体前端的挠曲线方程；根据气动和弹性之间的本质联系,提出了诱发攻角的概念,诱发攻角的动态具有简洁的表现形式并且可以同时描述非定常气动力和弹性形变的特性与联系；利用Lagrange方程建立了高超声速飞行器的飞行动力学方程,通过分析诱发攻角与刚体运动各变量的关系,对刚体模型进行修正,给出了包含气动弹性信息的高超声速飞行器非线性运动方程。所给出的高超声速飞行器气动弹性模型是后续工作中控制系统设计的基础。针对高超声速飞行器具有模型不确定性和参数不确定性、阵风干扰和大跨度机动飞行导致的系统参数剧烈变化等问题,在LPV系统框架内,将问题归结为标准的H∞问题,根据多胞LPV系统的特性,应用仿射参数依赖的Lyapunov方法,给出了LPV鲁棒变增益控制器算法；利用混合灵敏度思想,给出鲁棒变增益控制器的综合方法。随后将高度和速度作为调度变量,建立了LPV系统模型,并将模型转换为多胞LPV系统的形式。通过选择合适的加权函数和求解LMI问题综合得到了H∞鲁棒变增益控制器。应用得到的控制器解决高超声速飞行器巡航阶段和机动飞行阶段的姿态稳定问题,仿真结果表明控制器可以有效地保证干扰和不确定性存在条件下系统的稳定性；作为对比,给出了基于LTI系统设计的单点控制器在相应飞行条件下控制效果,对比结果表明在机动飞行时,LPV鲁棒变增益控制器具有更好的性能。根据高超声速飞行器的飞行任务需求,设计轨迹跟踪控制系统。根据频带分离原理,将被控对象分为高频回路和低频回路,采用多回路控制结构,分别综合得到了LPV姿态稳定控制器和轨迹跟踪控制器。将所获得控制器分别用于跟踪通用的周期衰减飞行轨迹和X43-A爬升测试飞行轨迹,仿真结果表明控制器可以有效地保证飞行器跟踪给定的轨迹指令。
[Abstract]:Hypersonic vehicles have been paid much attention by the world's military powers because of their broad application prospects in civil and military fields, and become the main research direction of aerospace flight technology. From the point of view of control science, these challenges mainly include the coupling between aerodynamic/elastic/control systems, the coupling between airframe and engine, the drastic change of system parameters caused by long-span flight, the inefficiency of control rudder surface and the near-critical stability of closed-loop systems. Aiming at the problems of aeroelastic analysis and control-oriented model of hypersonic vehicle, this paper analyzes the aerodynamic force and elastic deformation of hypersonic vehicle and the second one, according to the analysis problem, establishes the model, puts forward the problem, puts forward the control method, designs and synthesizes the controller. The nonlinear motion model of the aircraft is established by introducing new variables. The corresponding control algorithms are given for uncertainties and parameter variations respectively. A complete controller design and synthesis method is given to ensure the attitude stability of the aircraft during cruising and long-span flight. The airflow zoning characteristics of hypersonic vehicle in hypersonic flow are given, and the relationship between airflow characteristics and altitude, velocity and angle of attack is given. The resultant moments provide the basis for the subsequent analysis of the relationship between aerodynamics and elasticity, the establishment of hypersonic vehicle and the design of flight control system. Essential relationship between aerodynamics and elasticity is presented, and the concept of induced attack angle is proposed. The dynamic characteristics of induced attack angle have a concise form and can describe the characteristics and relations of unsteady aerodynamics and elastic deformation simultaneously. The nonlinear equations of motion of hypersonic vehicle with aeroelastic information are given by modifying the rigid body model. The aeroelastic model of hypersonic vehicle is the basis of control system design in the following work. In the framework of LPV system, the problem is reduced to a standard H problem. According to the characteristics of multi-cell LPV system, the algorithm of LPV robust variable gain controller is given by using affine parameter-dependent Lyapunov method. Secondly, the model of LPV system is established by taking altitude and speed as scheduling variables, and the model is transformed into a multi-cell LPV system. The H_ robust variable gain controller is synthesized by choosing suitable weighting function and solving LMI problem. The simulation results show that the controller can effectively guarantee the stability of the system in the presence of disturbances and uncertainties. As a comparison, the control effect of the single-point controller based on the LTI system under the corresponding flight conditions is given. The comparison results show that the controller can effectively guarantee the stability of the system in the presence of disturbances and uncertainties. According to the mission requirements of hypersonic vehicle, a trajectory tracking control system is designed. According to the principle of frequency band separation, the controlled object is divided into high-frequency loop and low-frequency loop. The LPV attitude stabilization controller and trajectory tracking controller are synthesized by using multi-loop control structure. The obtained controllers are used to track the general periodic attenuated flight trajectory and the X43-A climbing test flight trajectory respectively. The simulation results show that the controller can effectively guarantee the aircraft to track the given trajectory instructions.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：V211.47;V249.1

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