【作者】 秦昌茂；

【导师】 齐乃明；

【作者基本信息】 哈尔滨工业大学 ， 航空宇航科学与技术， 2011， 博士

【摘要】 随着高超声速技术的发展,对飞行器再入飞行控制系统提出了越来越高的要求。高超声速飞行器再入飞行过程中,动力学模型表现为具有大不确定性、强耦合的非线性系统,且飞行器在大气层内仅依靠气动力进行控制,控制能力有限,外界干扰对于弹体的影响也不能忽视,这使得高超声速飞行器再入飞行控制系统设计成为高超声速技术领域中的难题之一。本文主要针对高超声速飞行器再入飞行的高精度、强稳定控制问题开展研究。首先,选择空天飞行器(ASV)作为研究对象,建立和完善高超声速再入飞行条件下的飞行器的六自由度动力学及运动学方程。耦合特性分析表明了该模型能够反映高超声速再入飞行器是一类具有强耦合、快速时变的非线性系统,可以满足高超声速飞行器再入飞行控制系统等问题的理论研究和仿真验证需要。其次,针对具有大不确定性和复杂非线性等特性的高超声速飞行器姿态控制系统,并且考虑到再入飞行过程中飞行器所受的外界干扰等影响,本文结合自抗扰控制技术设计了再入自抗扰姿态控制器。通过构造qin函数实现了连续光滑扩张状态观测器的设计,减弱了传统扩张状态观测器应用过程中的高频颤振现象。将外干扰、模型不确定、通道间耦合及气动参数摄动影响作为“总和干扰”来获取干扰实时作用量,并通过改进的连续光滑扩张状态观测器进行实时动态反馈补偿,实现了系统的线性化。采用非线性反馈控制律来抑制补偿残差,提高了控制性能。进一步利用Lyapunov方法证明了该控制器的稳定性,为控制器参数选择提供了理论基础,通过仿真验证表明该控制器的有效性及鲁棒性。针对自抗扰控制器中采用非线性反馈控制律调参较困难的问题,采用分数阶PID控制律可以寻优整定参数,能获得更好的控制品质,较适用于单输入单输出系统。因此,针对单输入单输出系统,本文设计了自抗扰分数阶PID控制律。提出了最优Oustaloup数字算法实现分数阶微积分并建立分数阶PID控制器模型,结合连续光滑扩张状态观测器设计了自抗扰分数阶PID控制器。随后,利用自抗扰分数阶PID控制方法,研究了高超声速飞行条件下的飞行器再入滑翔段制导轨迹跟踪问题。结合再入飞行约束条件,建立了飞行器的阻力加速度—速度剖面再入走廊,选择适当的阻力加速度信号作为飞行器的参考轨迹,设计了飞行器再入制导轨迹跟踪控制系统。通过鲁棒性能量度分析表明分数阶PID具有更强的鲁棒性能,仿真结果表明了飞行器制导控制系统的有效性。针对分数阶系统建模采用阶次最大公因数法将导致模型阶次显著增加的问题,本文结合分数阶微积分算子的叠加原理,提出了变阶次状态空间建模方法。将分数阶系统推广到状态空间领域,实现了最小阶状态空间转换。对于各阶次均小于1的变阶次状态空间实现的分数阶系统,提出了变阶次分数阶系统的稳定性判定定理。分数阶系统变阶次状态空间建模及稳定理论有利于整数阶状态空间理论在分数阶系统中的推广应用。最后,结合分数阶系统变阶次状态空间建模理论,将分数阶微积分引入到高超声速飞行器下压段末导引律设计中,提出了再入下压段分数阶导引律,并结合最优控制理论得到导引律参数。仿真结果表明,相对于传统最优导引律,分数阶导引律提高了制导精度,对导引系数变化不敏感,同时由于分数阶微积分的引入,对下压初始点的参数偏差有良好的修正能力和较强的鲁棒性。更多还原

【Abstract】 As the development of hypersonic speed technology, the flight control system of reentry vehicle is made more and more high demand. In the reentry process of hypersonic vehicle, its dynamic model appears to a big uncertainty and strong coupling nonlinear systems, and control ability of the aircraft flying within the earth’s atmosphere is controlled only by aerodynamic con is limited. Furthermore, the external interference to the projectile also cannot be ignored. All these factors make the design of reentry control system of hypersonic vehicle becoming one of the challenges in the hypersonic technology field. This article mainly aims at the study of high precision and strong stable flight control of hypersonic vehicle.First, The paper choose aerospace vehicle (ASV) as the research object, and then establish and perfect the six-degree of freedom dynamics and kinematics equations at the condition of the hypersonic reentry. The analysis of the coupling character shows that this model can reflect hypersonic reentry vehicle is a kind of strong coupling, rapid time-varying nonlinear system, and also satisfy the demands of theoretical study and simulation validation of the flight control system of hypersonic vehicle.Secondly, for the hypersonic vehicle attitude control system of a large uncertainties and complex nonlinear characteristics of, also considering the external disturbance influence to the aircraft during the reentry process. Combining with the technology of auto-disturbance-rejection control, this paper designs an auto-disturbances-rejection gesture controller. We design the extended and smooth state observer by constructing Qin function, The high frequency vibration phenomenon in the process of its traditional application is also weakened. We make the outside interference, uncertain model, coupling channel and pneumatic parameter perturbation influence as a "total interference" to get the value of the real-time interference. Through the improvement of extended and smooth state observer, it realize the real-time dynamic feedback compensation and the linearization of the system. By using nonlinear feedback control law to curb compensation residual, the control performance is improved. Moreover, we show the controller’s stability using Lyapunov function, and provide basic theory to the selection of controller parameter. Through the simulation results, show the controller is of validity and robustness.Auto-disturbances-rejection controller using nonlinear feedback control law is difficult to get parameters , by using nonlinear PID control law can seek virtues and operate values, also obtain better control quality , thus it is more suitable for single input and single output system. Therefore, this paper puts forward Oustaloup digital algorithm to realize the optimal fractional calculus and establish fractional PID controller model, and design auto-disturbances-rejection fractional order PID controller basing on the extended state observer.Then, using auto-disturbances-rejection fractional PID control method, we study trajectory tracking matters in the reentry gliding process of the aircraft at the hypersonic flight conditions. Basing on the flight constraints, the aircraft resistance acceleration - velocity profile reentry corridor is made. By selecting the appropriate resistance acceleration signal as aircraft reference trajectory, we design the reentry guidance trajectory tracking control system of the aircraft. Through the analysis of the performance measure of the robust energy indicates that fractional order PID has stronger robustness. Simulation results show the validity of the vehicle guidance control system.To solve the fractional order system modeling will lead to obvious increase of the model order. So, in this paper, we put forward a changing order times state space modeling method, make the fractional systems extend to the state space area, realize the minimum order state space conversion basing on the superposition principle of fractional order operator. For whose order times are less than 1 variable order state space achieving fractional order systems, A changing order fractional order system’s stability criterion theorem is put forward. Fractional order system’s changing order state space modeling and stability theory is beneficial for the extended application of integer order state space theory in the fractional order systems.Finally, the fractional calculus will be introduced to the guidance law design of the hypersonic vehicle press section and puts forward a fractional guidance law of the reentry press section basing on the fractional order system’s changing order state space model,select parameters of fractional guidance law with optimal control. Through the analysis results, compared with the traditional proportional guidance law, fractional guidance law raised the guidance accuracy, is not sensitive to guide coefficient change. At the same time, because of the introduction of fractional calculus, it has strong robustness and a good correction ability to the deviation parameters of the reentry points.更多还原