一种基于模糊控制的平稳滑翔再入制导律

针对升力式高超声速飞行器(LHV)再入滑翔过程中的周期性振荡现象，提出了一种基于模糊推理与控制的反馈调节方法以抑制振荡实现平稳滑翔。纵向制导在落点误差预测及指令校正的基础上，在倾侧角外环控制回路增加以高度变化率及空速作为输入的模糊控制器对倾侧角指令进行调节，横侧向制导通过航向角误差走廊约束及倾侧角反转逻辑实现大横程条件下的侧向控制。所提方法不依赖于准平衡滑翔条件(QEGC)，同时避免了参数化反馈控制律中的反馈项参数设计问题，具有较强的自适应能力。LHV制导实例仿真表明，所提方法可有效抑制振荡现象，满足终端约束及再入走廊约束，方法的鲁棒性也通过Monte Carlo仿真得到了验证。 

A reentry steady glide guidance algorithm based on fuzzy control

Considering the periodic oscillation in reentry glide of Lifting Hypersonic Vehicle (LHV), a feedback correction method based on fuzzy logic and fuzzy control is proposed to reduce the oscillation and keep reentry glide trajectory smooth. First, the longitudinal guidance is developed based on the prediction of the landing error and the correction of the guidance command, and a fuzzy controller whose input consists of altitude ratio and airspeed is applied to outer loop of the bank angle control system. Then, the lateral guidance is designed by the course angle error corridor and bank reversal logic, which realizes the lateral controls in large transverse range conditions. This method is independent of Quasi-Equilibrium Glide Condition (QEGC) and the problem of parameters design in parametric feedback law is avoided, which enhances the adaptive ability. Based on LHV model, the numerical simulations show that periodic oscillation is effectively reduced by the fuzzy feedback control law within terminal and reentry corridor constraints. Meanwhile, the Monte Carlo simulation with random dispersions and errors verifies the robustness of the proposed algorithm.