基于二阶滑模的再入飞行器末制导律研究

Research on Terminal Guidance for Re-Entry Vehicle Based on Second-Order Sliding Mode Control

针对再入飞行过程中飞行器末制导启动后制导系统存在的模型不确定性因素以及气动环境复杂等鲁棒制导问题,结合落点角约束条件,提出一种基于二阶滑模的鲁棒末制导律设计方法。基于二阶滑模控制的思想,设计有限时间收敛的二阶滑模末制导律;为了消除有界的内外扰影响同时削弱抖振效果,引入超螺旋算法设计有限时间收敛的连续二阶滑模末制导律。飞行器在该末制导律导引下,弹目视线角速率及落角约束快速收敛,从而保证飞行器有很高的命中精度。基于Lyapunov定理的稳定性理论证明及仿真结果均表明了该末制导方案的有效性。

A new robust terminal guidance law based on second-order sliding mode control is proposed for the problems existing in vehicle re-entry phase after starting of terminal guidance system,such as model uncertainty,complex aerodynamic conditions and constraint conditions for falling angle.Based on second-order variable structure control theory,a terminal guidance law with finite convergence time is designed;meanwhile,in order to weakening the influence of disturbance and chattering,a super-spiral algorithm is introduced for designing the second-order sliding mode terminal guidance law with finite convergence time and continuous control effect.Controlled by this guidance law,the angular rate of line-of-sight（LOS） and constraint conditions for falling angle can converge quickly,thus ensuring higher guidance accuracy.Theoretic proof of stability based on Lyapunov theorem and simulation results show that the proposed guidance law is effective.