Augmented safety guarantee-based area keeping control for an underactuated USV with environmental disturbances

This paper proposes an accurate area keeping control method with augmented safety guarantee for an underactuated unmanned surface vessel (UUSV) with environmental disturbances. It can mediate the safety and the stability during the UUSV area keeping control. Firstly, inspired by the notion of control barrier function (CBF) in general manifolds, an augmented safety guarantee is constructed to deal with the nonlinear safety constraints of the area keeping control for the UUSV. Then, the stability constraints for the UUSV area keeping control are formed by involving a control Lyapunov functions (CLF) and a weather optimal control (WOC) method. Finally, by unifying the augmented safety guarantee and the stability constraints, an accurate area keeping controller is designed through a quadratic program (QP), which can consider the safety problem into the optimal area keeping control of the UUSV under environmental disturbances. Comparing the proposed method to the WOC, simulation results validate the feasibility and the superiority of the proposed method.