Decentralized robust H_∞ controller design for bank-to-turn missile with coordinate loop

Because of the high angle of attack and rapid roll movement of bank-to-turn (BTT) missile, the nonlinear kinematic coupling between three channels can not be ignored. For this problem, an coordinated robust H_∞ controller based on decentralized control theory is proposed. According to the expected dynamic characteristics of the system, a reference model is designed for each subsystem. Coordinate loops are induced to slake the main nonlinear coupling, and the uncompensated coupling is assumed to satisfy a quadratic constraint. Based on the robust control theory and the precondition that the coupling is quadratic bounded, controllers are designed to guarantee the asymptotic stability of the overall system, and the H_∞ norm of the generalized system is minimized. The sufficient condition of the controller's existence is generalized to the optimization of a linear matrix inequality. Simulation shows the validity of the proposed control scheme.