Path Following Control With Sideslip Reduction for Underactuated Unmanned Surface Vehicles

For underactuated unmanned surface vehicles (USVs), the uncontrollable nonzero sway velocity leads to the sideslip phenomenon, bringing difficulties in tasks with high attitude requirements. This article proposes a path following control algorithm for underactuated USVs, which can reduce the sideslip angle on a curved path. A novel path following approach by controlling two points on the USV is developed, one of which is used for guaranteeing position error convergence, and the other is used for an optimization problem to reduce the sideslip angle. In order to reduce the influence of the sway velocity on the curved path, a surge speed regulator is designed to adjust the desired surge speed according to the curvature of the desired path at the current position. Numerical simulations and experiments are carried out, and the results show that the sideslip angle is significantly reduced while the position error exponentially converges to zero.