3D Variable Structure Guidance Law Based on Adaptive Model-following Control with Impact Angular Constraints

Abstract

This paper proposes a new three-dimensional (3D) guidance law for the impact angles control, using the variable structure control theory. In order to study the problem of the precision guidance, the three-dimensional terminal motion of air-crafts is divided into the motion in the vertical plane and the bank plane. Then the decoupling control of the guidance law is designed independently. After the linear optimal guidance laws are designed with terminal multi-constraint conditions of miss-distance, impact trajectory inclination angle and impact trajectory rotation angle, we let the linear optimal model act as the referenced model and take the linear optimal input as the reality system's referenced input. According the model matching condition, the guidance parameters are updated by variable structure laws to ensure high precision in the impact angle conditions. Some simulations of the characteristic trajectory are performed. The simulation's results show the variable structure guidance law based on adaptive model-following control is not only satisfied with the need of precision guidance and impact angular constraints, but also have excellent trajectory in terminal guidance.