H-infinity mixed sensitivity design for sampled-data system of endoatmospheric interceptors

The overload tracking control system of an endoatmospheric interceptor is designed, in which the interceptor's attitude is controlled by the combination of lateral jet thrusters and aerodynamic surfaces. The elevators' and the interceptor' motions are viewed as continuous variables, while the lateral thrust provided by impulse thrusters is treated as a discrete control variable. Then, based on the hybrid control concept, the whole system can be regarded as a sampled-data system after the elevators' controllers have been designed. Then control methods for sampled-data system can be used to the system synthesis and design. The H-infinity mixed sensitivity method for sampled-data systems is employed to design a discrete controller for the lateral thrust to achieve fast response of angle-of-attack for overload tracking. Numerical simulation shows the effectiveness of the proposed approach.