Adaptive Fuzzy Control of Autonomous Underwater Vehicle via Performance Observer and Disturbance Observer

In this paper, based on disturbance observer (DO), an adaptive fuzzy control design is presented for autonomous underwater vehicle (AUV). The considered nonlinear system contains model uncertainty, external disturbance. Fuzzy logic systems (FLS) with online adaptations are utilized to estimate unknown nonlinear functions. And a fuzzy performance observer is constructed, whose estimation error is used to design a fuzzy disturbance observer (FDO) to estimate the external disturbance. H
∞
control technique is adopted to overcome the effects of the estimation error of external disturbances. Then the stability analysis and tracking performance of the closed-loop system are verified based on the Lyapunov stability theory, such that all the states of the system are uniformly ultimately bounded. Finally, the simulations on an AUV show that the proposed scheme is effective in addressing the tracking control problem of AUV in the presence of model uncertainties and external disturbance.