Nonlinear Adaptive Fuzzy State Observer Design for the Dynamic Positioning System of Ships

Abstract

A nonlinear adaptive fuzzy state observer is constructed for the dynamic positioning (DP) system of ships in the presence of unknown time varying disturbance based on the passive observer structural principle and Lyapunov stability theory in this paper. The unknown time varying disturbance is estimated by the fuzzy universal approximation lemma in the proposed observer design. Comparing to the traditional observer, the main advantage of the nonlinear adaptive fuzzy state observer is the ability to adjust the online parameter real-timely and the global exponential stability (GES) is guaranteed. Finally, the simulation research is carried out on a supply ship, which shows that the designed nonlinear adaptive fuzzy state observer has good performances of filtering and state estimation. The effectiveness of the nonlinear adaptive fuzzy state observer for DP system of ships is verified.