Three dimensional impact angle constrained integrated guidance and control for missiles with input saturation and actuator failure

A three dimensional integrated guidance and control law with impact angle constraint is developed, using the dynamic surface control and extended state observer techniques, for the bank to turn (BTT) missile attacking a ground fixed target in the presence of input saturation and actuator failure. Firstly, a novel three dimensional integrated guidance and control model based on Coriolis theorem is built without assuming the angle between line of sight and missile velocity is small or almost constant. Then, to analyze the effect of input saturation on missile's integrated guidance and control system, a smooth tangent function, a Nussbaum function, and an auxiliary system are introduced. The actuator failure, modeling error, and aerodynamic parameters perturbation are viewed as the lumped system uncertainty. Three extended state observers are designed to estimate uncertainty. With the signal generated by the auxiliary system and uncertainty estimate from extended state observer, a robust controller is designed using dynamic surface control technique to track the desired impact angle. The stability of system is proved using Lyapunov theory. Numerical simulations are implemented to demonstrate the effectiveness and robustness of the integrated guidance and control law.