Abstract
In this paper, a path-following control (PFC) problem of an underactuated surface vehicle (USV) is scrutinized based on an interval type-3 fuzzy logic system (IT3FLS). The suggested method is able to tackle the main limitations of the singleton fuzzy controller in terms of the approximation ability for uncertainties and exogenous disturbances of a complex nonlinear USV. Since a novel structure is employed for the FLS, the control policy is capable of ensuring robust performance against uncertainties with a wide range of variations and higher volumes of complex disturbances. Moreover, surge-guided line-of-sight (SGLOS) and auxiliary dynamics are utilized to design surge and heading control policies, adjusting the velocity of a vehicle and its position at each moment respective to the predefined path. Predictive compensators are designed to enhance the robustness by reducing the approximation error signals while the stability analysis of both tracking and approximation error signals are investigated based on the Lyapunov approach and Barbalat's lemma. Finally, simulation results demonstrate the effectiveness of the suggested improved fuzzy-based control strategy to solve a PFC problem.