考虑输入饱和的高超声速飞行器反步法控制

为解决输入饱和、参数不确定和气动弹性影响下的高超声速飞行器控制问题,提出一种基于反步法的非线性鲁棒自适应控制方法.针对高超声速飞行器纵向通道控制问题,将其分解为速度子系统和高度子系统分别进行控制器设计.首先,基于Lyapunov稳定原理设计了参数估计自适应律来处理输入受限情况的速度跟踪控制问题,即使出现推力饱和也能保证系统稳定性;然后,采用自适应反步法对高度子系统进行分层递推设计,通过引入自适应律对不确定参数进行在线实时估计,以提高控制器的鲁棒性,并且实现了高度的稳定跟踪;同时利用微分跟踪器来获取虚拟控制指令导数;采用鸭翼与升降舵联动控制策略,通过选取合适的联动控制增益可以同时消除控制面与升力耦合带来的非最小相位特性和控制输入对一阶弹性模态的激励;最后,基于LaSalle不变集原理证明了闭环控制系统的稳定性.仿真结果表明,所设计的控制器能够有效处理弹性高超声速飞行器的气动参数不确定和控制饱和问题,并且具有良好的闭环跟踪性能.

Adaptive backstepping control of a flexible hypersonic vehicle with input saturations

This paper proposes a robust nonlinear control strategy based on adaptive backstepping method to cope with flight control for an air-breathing hypersonic vehicle with input saturation, parameter uncertainties and flexible effects.For the hypersonic-vehicle longitudinal control problem, the controller is designed separately for the velocity and height subsystems.An adaptation law derived from Lyapunov stability principle is adopted for the design of velocity subsystem controller to deal with engine physical limits, the stability of input saturation system is guaranteed.To improve robustness, a backstepping method with adaptive parameter online estimation is introduced to realize the stable tracking of altitude reference trajectory.By choosing a desirable inter-connect gain, the canard works in conjunction with the elevator to suppress the first-order mode under the excitation of control input and improve non-minimum phase behaviour.The derivatives of virtual control are achieved via a tracking differentiator.Based on the LaSalle-Yoshizawa theorem, the proposed control design is proved to be stable.Simulation results show the effectiveness of the control strategy despite the presence of parameter uncertainty, input saturation and aeroelastic effects.