Path-Following for the Dynamic Model of a Marine Surface Vessel without Closed-Loop Control of the Surge Speed

The paper presents a novel path-following solution for the dynamic model of an underactuated marine surface vessel. The proposed solution does not require closed loop control of the surge speed, but rather only of the yaw rate. In particular, the velocity of a virtual target on the path and a reference angular velocity for the vessel are computed such that if the vessel and the target had such velocities the path-following problem would be asymptotically solved at kinematic level. Then, applying feedback linearization to the dynamic model of the surface vessel, a yaw torque command is computed in order to steer the vessels total velocity on the desired reference value. The resulting control law for the yaw degree of freedom results in nonlinear terms (from feedback linearization) and PI terms. Numerical simulations are provided to validate the proposed approach. ©IFAC 2010.