An Adaptive Line-of-Sight Guidance Law for Trajectory Tracking of USV with LADRC

This article proposes an trajectory tracking control strategy for underactuated unmanned surface vessels (USVs) by combining an improved line-of-sight (LOS) guidance law and an adaptive disturbance rejection control (ADRC) approach considering unknown model parameters and time-varying external disturbances. In terms of kinematics, to eliminate the influence of wind, waves, and ocean currents, the proposed guidance law compensates for sideslip angle by means of adaptive control and is proved to be globally k-exponentially stable. With respect to kinetics, this study develops separate longitudinal velocity and heading angle controllers for USVs without requiring prior knowledge of the vessel's characteristics. These controllers are designed using the linear adaptive disturbance rejection control (LADRC) approach, which minimizes the number of parameters that need adjustment. The resulting composite trajectory tracking controller exhibits a concise form that facilitates practical implementation. Finally, the effectiveness of the proposed control strategy is verified by simulation.