Predictor-Based Fixed-Time LOS Path Following Control of Underactuated USV With Unknown Disturbances
Shandan Wang, Mengwei Sun, Yihang Xu, Jian Liu, Changyin Sun
Abstract
This paper investigates the path following problem of underactuated unmanned surface vehicle systems suffering unknown disturbances. A fixed-time predictor is proposed to approximate the sideslip caused by disturbances, by which the prediction error can converge to zero in a fixed time. By selecting appropriate controller parameters, the upper bound of settling time is identified. And it's independent of initial conditions, compared with the finite-time predictor. In addition, a fixed-time line-of-sight (LOS) guidance law and a fixed-time heading controller are proposed. The cascade system composed of the guidance law and heading controller is fixed-time stable. All states of the Unmanned surface vehicles (USV) system can be stabilized globally in a fixed time, and USVs can follow the desired path accurately. Finally, numerical experiments are given to illustrate the effectiveness and feasibility of the proposed algorithm.