Hybrid nonfragile intermediate observer-based T-S fuzzy attitude control for flexible spacecraft with input saturation

Abstract

This paper investigates a hybrid nonfragile intermediate observer-based T-S fuzzy attitude control strategy subject to multi-source complex disturbances to achieve integrated attitude stabilization and vibration suppression for the flexible spacecraft. A refined T-S fuzzy model for flexible spacecraft is introduced to represent the nonlinear characteristics in large-angle attitude maneuver. Then a hybrid nonfragile observer with coexisting additive and multiplicative perturbations is designed to estimate state information and disturbance simultaneously. Consequently, based on the closed-loop system, the quadratic stability and robust H∞ performance are proved via the Lyapunov stability analysis with corresponding conditions in terms of linear matrix inequalities (LMIs). It is worth mentioning that different from the limiter directly used in much literature, input saturation is disposed as a disturbance during the proof to satisfy the stability requirements. Finally, numerical simulations of a flexible spacecraft attitude control system are performed which demonstrate the effectiveness and superiority of the proposed control strategy.