一类高超声速飞行器自适应容错控制器设计

Hypersonic aircraft adapative fault-tolerant controller design

高超声速飞行器控制系统具有非常突出的强耦合、强非线性、时变的力学特性,在其研究与设计过程中,需要处理高速飞行带来的弹性形变、多输入多输出、气动参数不确定以及高温高热等原因导致的各种传感器故障和部分作动器故障等一系列问题,因此该类飞行器控制系统的研究与设计面临着传统飞行器控制系统研究所未有的困难和挑战.针对高超声速飞行器飞行过程中遇到的部分作动器故障问题,本文提出了非线性观测器与控制器一体化设计的高超声速飞行器自适应反演容错控制方法.首先将飞行器作动器故障模型转换为一类状态不能完全测量,且具有未知参数和未知控制增益的SISO输出反馈非线性最小相位系统,然后,基于改进的K-滤波器理论对状态向量进行重构,在系统只有输出可以测量的情况下,设计了一种新型观测器,确定出收敛的状态向量,设计出强自适应能力的控制器,保证了系统所有信号的有界性.在自适应反演设计时,采用动态面设计方法,引入一阶滤波器,得到虚拟控制量的微分,消除传统反演设计中的"项数膨胀"问题,用Lyapunov稳定性定理保证误差一致有界.仿真实验验证了该算法的有效性.最后以高超声速飞行器纵向通道为例,验证了上述理论.

The hypersonic aircraft control system design must deal with the extra prominent dynamics charac- teristics： highly coupled, strongly nonlinear, time variationM and so on. Thus, during the course of control system study and design for the hypersonic aircraft, the following factors must be considered： plant elastic deformation, multi-inputs multi-outputs, uncertain aerodynamatic parameters, sensors and actuator failures, which is differ from the traditional aircrafts control system design. To solve the failure problem of the actuator in the course of the hypersonic aircraft flight, one kind of adaptive backstepping fault-tolerant control method based on the observer and controller designed synthetically is brought up. At first, we develop the research model based on a SISO output feedback nonlinear unobservered minimum phase system under the condition of single channel actuator failure of the hypersonic aircraft, then adopt K-filter to reconstruct state vectors. When only the output is measureable, the dissertation designs one new observer to estimate convergence state vector and design the adaptive control law to guarantee the system boundedness. In the course of adaptive backstepping design, the dissertation employes the dynamic surface control strategy to eliminate the explosion of terms by introducing a series of first order filters to obtain the differentiation of the virtual control inputs. Lyapunov stability theorem guarantees the error uniformly bound. Both theory analysis and simulation verification show the simplicity and effectiveness of this method. At last the pitch channel of hypersonic aircraft is studied as an example to validate the above theory.