In this article, a sliding mode control–based nonlinear guidance scheme for controlling both impact angle and impact time simultaneously is proposed. The problem of impact angle control is first transformed to that of controlling line-of-sight angle and its rate, while the requirement of impact time is achieved by tracking the desired time-to-go. The chosen time-to-go estimate accounts for the curvature required to meet the impact angle requirements toward the target interception. In order to satisfy both of these terminal constraints, the sliding surface is defined as a combination of impact time error and the variable pertaining to the errors in line-of-sight angle and its rate, with appropriate gains assigned to them. The interceptor first performs necessary maneuvers to meet the impact time requirements and then steers its course to achieve the target interception at a desired impact angle. The guidance law is initially derived using nonlinear engagement kinematics against stationary targets and then extended to cater to constant velocity targets using the concept of predicted interception point. Numerical simulations are performed to validate the efficacy of the proposed guidance scheme for various initial engagement geometries. The performance of the proposed guidance scheme is also compared with those of the existing guidance laws and shown to be superior.

在本文中，提出了一种基于滑模控制的非线性制导方案，用于同时控制撞击角度和撞击时间。撞击角控制问题首先转化为控制视线角度及其速率的问题，而撞击时间的要求则是通过跟踪所需的剩余时间来实现的。所选的剩余时间估计考虑了满足对目标拦截的撞击角度要求所需的曲率。为了满足这两个终端约束，滑动表面被定义为撞击时间误差和与视线角度误差及其速率相关的变量的组合，并为其分配适当的增益。拦截器首先执行必要的机动以满足撞击时间要求，然后转向以所需的撞击角度实现目标拦截。制导律最初是使用针对静止目标的非线性交战运动学推导出来的，然后使用预测拦截点的概念扩展到迎合等速目标。进行数值模拟以验证所提出的制导方案对各种初始接合几何形状的有效性。所提出的指导方案的性能也与现有指导法的性能进行了比较，并显示出优越性。制导律最初是使用针对静止目标的非线性交战运动学推导出来的，然后使用预测拦截点的概念扩展到迎合等速目标。进行数值模拟以验证所提出的制导方案对各种初始接合几何形状的有效性。所提出的指导方案的性能也与现有指导法的性能进行了比较，并显示出优越性。制导律最初是使用针对静止目标的非线性交战运动学推导出来的，然后使用预测拦截点的概念扩展到迎合等速目标。进行数值模拟以验证所提出的制导方案对各种初始接合几何形状的有效性。所提出的指导方案的性能也与现有指导法的性能进行了比较，并显示出优越性。