Integrated controller-observer system for marine surface vessels

摘要

A robust nonlinear controller has been designed to control the surge speed and the heading angle of a marine surface vessel. The control actions are carried out through the propeller and the rudder. Moreover, a nonlinear observer has been devised to accurately estimate the surge speed and the yaw angle and their time derivatives. Both the controller and the observer are designed based on a reduced-order model of the ship. However, their performances have been assessed on a six degree-of-freedom ship model, which accounts for the wave excitation, retardation forces, nonlinear restoring forces, wind and sea-current resistive loads. Furthermore, the model accounts for the physical limitations of both the rudder and the ship propulsion system. The simulation results demonstrate the capability of the integrated controllerobserver system in providing a good tracking characteristic of the ship in spite of significant modeling imprecision and environmental disturbances.