Disturbance-observer-based guaranteed cost fuzzy control for airbreathing hypersonic vehicles

This paper addresses the problem of disturbance-observer-based guaranteed cost fuzzy control (GCFC) for the longitudinal dynamics of a generic airbreathing hypersonic vehicle (AHV). Firstly, a Takagi-Sugeno (T-S) fuzzy linear model is employed to approximate the nonlinear dynamics of AHV and the unknown external disturbance is supposed to be generated by an exogenous linear system, respectively. Subsequently, a disturbance observer is proposed to estimate the unknown disturbance and an augmented fuzzy system is constructed by integrating the dynamics of AHV and the disturbance estimation error. Then, a suboptimal GCFC design is developed by means of the linear matrix inequalities (LMIs), which can guarantee that the closed-loop augmented system is asymptotically stable but also provide an optimized upper bound on the quadratic cost function for the AHV. Finally, simulation results demonstrate the effectiveness of the proposed fuzzy controller.