Dynamic positioning of ships based on robust fuzzy observer

In this study, the robust fuzzy observer-based control scheme for the dynamic positioning of marine vessels is presented. The proposed controller assumes that the environmental disturbances are unknown but bounded with known upper limit. First, the authors apply the Takagi-Sugeno fuzzy model to approximate the ship model. Using formulated fuzzy model, the robust fuzzy observer is developed to approximate the unknown states. Then, by employing optimal H-infinity disturbance attenuation technique, the effects of the environmental disturbances can be attenuated to least value. Finally, the linear matrix inequality technique is hired for solving the optimal robust problem. Model ship is used for simulation, and results are given to prove the validity of the presented controller.