Track-keeping observer-based robust adaptive control of an unmanned surface vessel by applying a 4-DOF maneuvering model

Abstract

Abstract The present study addresses the speed and steering controller design for the maneuvering motions of an unmanned surface vessel (USV). Based on a 4-DOF nonlinear mathematical model for the maneuvering motions of the proposed USV with multi-inputs and multi-outputs, an adaptive sliding mode controller based on Lyapunov analysis is designed to follow the desired velocity and to estimate unknown parameters for the separated surge motion. In addition, for the steering motion control, an augmented model including the heading motion and output tracking error integral is presented. In accordance with the proposed model, an observer-based model reference adaptive controller is developed, leading to a convex optimization problem subject to matrix inequalities. The reference heading angle is extracted from an adaptive line-of-sight (LOS) guidance algorithm based on waypoints. Finally, the simulation results of tracking several maneuvering motion paths indicate the efficiency of the proposed approach is satisfactory and superior compared with PID controller.