Disturbance Observer-Based Path Following Control of Unmanned Surface Vessel with Control Input Saturation and Unknown Disturbance

This study proposes a nonlinear disturbance observer-based path following control scheme for unmanned surface vessel (USV) in the presence of input saturation and unknown external disturbance. The dynamic surface control (DSC) framework is augmented by a robust adaptive radial basis function neural network (RBFNN) and a nonlinear disturbance observer (NDO). The control strategy can avoid the differential explosion problem inherent from traditional backstepping approach. The boundary value of the estimated disturbances that are presented in a number of existing disturbance observers is relaxed.