Control algorithm for designing anti-ballistic missile terminal guidance law

The problem on control algorithm for designing anti-ballistic missile terminal guidance law is studied. Conventionally the target's acceleration is often assumed to be known or needs to be estimated in real time. Our control algorithm differs from the conventional approach. We consider the relative kinematics equation of the missile and target to be an uncertain nonlinear system with structure perturbation and disturbance. The Lyapunov stability theory is used to derive the robust adaptive variable structure controller for generic multiplex uncertain nonlinear system with structure perturbation and disturbance. The control algorithm can estimate the uncertain boundary of structure perturbation and disturbance on the premise that the stabilization of close-loop system is guaranteed. The control algorithm is applied to design the anti-ballistic missile terminal guidance law. It considers the target's acceleration as the input disturbance and derives the strong robust adaptive guidance law based on zeroing normal speed of LOS (line of sight). The adaptive law can estimate the uncertain boundary of target's maneuvering acceleration. Finally the numerical simulation results indicate that the guidance law exhibits strong robustness properties against disturbances from target's maneuvers. The guidance algorithm is simple and never needs the boundary of the acceleration of target, so it is more convenient for comprehension and practical implementation.