Adaptive Fuzzy Hybrid Optimal Event‐Triggered Output‐Feedback Control for an Unmanned Surface Vehicle System

ABSTRACT This paper investigates an adaptive fuzzy hybrid optimal event‐triggered output‐feedback control strategy for an unmanned surface vehicle (USV) subject to external disturbances. To estimate the unmeasurable velocities of the USV system and reduce the number of actuator updates, a fuzzy state estimator is designed and two event‐triggered mechanisms are established. Subsequently, a novel adaptive fuzzy hybrid optimal event‐triggered output‐feedback control scheme is proposed, which consists of a feed‐forward adaptive fuzzy controller and an optimal error feedback controller. The former is designed using a recursive backstepping design, while the latter is formulated within the adaptive dynamic programming (ADP) framework. It is shown that the designed hybrid optimal control scheme ensures that all variables in the USV system are uniformly ultimately bounded (UUB) while achieving optimal control performance. Simulation results are given to verify the effectiveness of the developed fuzzy hybrid optimal control scheme.