Valiollah Ghaffari

In this thesis, nonlinear trajectory control of an autonomous sailboat using a fuzzy predictive control method is presented. The development of marine robots has attracted the attention of the control community in the past decades, as the nonlinearity of the model, unmodeled or roughly estimated hydrodynamics, parametric model uncertainty, and unmeasured disturbances make it a challenging problem. First, the system model is linearized for several operating points and predictive control of the model is designed for the system. Then, fuzzy logic is used for the interval between these operating points. Model predictive control has advantages over other control methods, such as the ability to consider system constraints and easy implementation in digital systems. This research presents a new control method for autonomous sailing boats that includes both direction control and speed control by adjusting the angles of the rudder and sail. This method facilitates the development of a nonlinear model, which is essentially a collection of a number of quasi-linear models that are regulated by fuzzy logic. The highly nonlinear model of an autonomous sailboat was defined and modeled in Matlab software, and then simulated in the Simulink environment, and the results were presented.