带攻击角度约束的自适应终端滑模导引律

针对某些导弹在对目标进行打击时需要满足零脱靶量和攻击角度约束的要求，首先基于终端滑模控制和有限时间控制理论，改进了一种快速收敛的非奇异终端滑模函数，用于设计滑模面，结合自适应指数趋近律，提出了一种自适应非奇异终端滑模控制方法，解决了传统终端滑模控制中存在的奇异问题，并使状态变量在有限时间内快速收敛到平衡点。然后将所提方法用于导引律的设计，提出了一种带攻击角度约束的自适应非奇异和有限时间收敛导引律，实现了导弹对脱靶量和攻击角度约束的要求；采用有限时间控制理论对该导引律的收敛特性进行了分析，证明了制导系统状态的全局有限时间快速收敛特性。与传统的非奇异终端滑模导引律相比，本文所提导引律能够在更短的时间内以更小的脱靶量和更高精度的攻击角度对目标实施打击。最后进行了大量的对比仿真实验，仿真结果验证了所提导引律的有效性。 

Adaptive terminal sliding mode guidance law with impact angle constraint

Aimed at the requirement of zero miss-distance and terminal impact angle constraint for some missiles attacking the targets, an adaptive nonsingular terminal sliding mode control algorithm based on the theories of terminal sliding mode control and finite-time control is proposed first. The algorithm avoids the singularity of terminal sliding mode control, and makes the state variables achieve the equilibrium point by improving a fast nonsingular terminal sliding mode function to construct the sliding mode surface, and employing an adaptive exponential reaching law. Then the algorithm is utilized to design the guidance law, and an adaptive nonsingular and finite-time convergent guidance law with impact angle constraint is proposed. Realizing the requirement of miss distance and attack angle of the missiles. Finite-time control theory is used to analyze the convergence of the guidance law, and proves the fast and finite-time convergence of guidance system states during the whole process. Compared with conventional nonsingular terminal sliding mode guidance law, the designed guidance law can attack the targets with less miss-distance and higher precision of expected impact angle in a shorter time. A large number of simulation experiments verify the validity of the proposed law.