基于跟踪微分器的高超声速飞行器Backstepping控制

针对存在模型参数不确定和外部干扰的高超声速飞行器（HFV）跟踪控制问题，提出一种基于Backstepping方法的抗饱和非线性控制器。将飞行器纵向动力学模型分为速度子系统和航迹倾角子系统，然后针对每个子系统单独设计控制器。设计跟踪微分器获得信号的一阶导数，用以估计系统中的不确定干扰项和避免"微分项膨胀"问题。控制器设计过程考虑了控制量发生饱和的情况。基于Lyapunov理论证明了闭环系统信号的稳定性。与传统高超声速飞行器Backstepping方法相比，所设计的控制器采用待跟踪状态与理想控制指令之间的实际误差作为反馈量，放宽了对系统干扰项的限制，提高了控制器对控制增益变化的适应性，进而提高了闭环系统的跟踪控制性能。对比仿真结果验证了所设计方法的有效性。

Backstepping control for hypersonic flight vehicles based on tracking differentiator

For the problem of tracking control of the Hypersonic Flight Vehicle (HFV) with uncertain model parameters and external disturbances, a Backstepping-based anti-saturation nonlinear controller is proposed. The longitudinal dynamical model of the vehicle is divided into the velocity subsystem and the flight path angle subsystem, and then the controller is designed individually for each subsystem. A tracking differentiator is designed to obtain the first derivative of a signal, which is used to estimate the uncertainties existing in systems and avoid the problem of "explosion of complexity". Occurrence of saturation of control inputs is considered in the design of the controller. The stability of closed-loop system signals is proved based on the Lyapunov theory. In comparison with the conventional Backstepping method applied to HFVs, the proposed method adopts the actual error between the state to be tracked and the desired control command as the feedback variable, relaxes the restriction on system disturbances and improves the adaptability of controller to variation of control gains, which enhances the tracking control performance of the closed-loop system. The comparative simulation results verify the effectiveness of the proposed method.