基于扰动观测器的高超声速飞行器递阶滑模控制

针对存在扰动、执行机构死区非线性以及系统不确定性的高超声速飞行器巡航飞行纵向通道模型,提出了带有新型非线性扰动观测器的递阶滑模控制器。递阶滑模控制器采用多层终端滑模面的回归结构,能够保证系统跟踪误差在有限时间内收敛到0.将执行机构的死区非线性简化为输入的未知扰动,对于系统中存在的由扰动和不确定性产生的复合扰动,设计了新型非线性扰动观测器,补偿作用避免了通过增大系统增益提高控制系统抗扰动性能,同时观测器可以对死区非线性产生的系统扰动进行观测,消除死区非线性对控制系统的影响。理论证明了观测值误差为渐进收敛。基于Lyapunov理论对带有扰动观测器的综合控制系统进行稳定性证明。理论分析和仿真结果表明,该控制策略对高超声速飞行器具有较好的控制作用。

Recursive Sliding Mode Control for Hypersonic Vehicle Based on Nonlinear Disturbance Observer

A recursive terminal sliding-mode controller (RTSMC) with nonlinear disturbance observer (NDO) is proposed for the longitudinal dynamics model of generic hypersonic flight vehicle in the presence of external disturbances, unknown dead-zone nonlinearity and system uncertainties. RTSMC employs a recursive procedure which contains a set of terminal manifolds to make system tracking error converge to zero in a finite time. The dead-zone nonlinearity of the actuator is simplified as unknown input disturbance. For the compound disturbance generated by the external disturbances and system uncertainties, a novel NDO is developed, which can reduce the conservatism of RTSMC and eliminate the influence of dead-zone nonlinearity on system. The stability of the proposed control strategy is proved by means of Lyapunov theory. Several numerical examples are provided to compare and verify the proposed method.