Robust stabilization of underactuated surface vessels with parameter uncertainties

For regulation of an underactuated surface vessel with parameter uncertainties, a simple robust sliding-mode controller is proposed yielding global exponential convergence of the vessel's position and orientation to origin. First, a kinematic controller for surge and yaw velocities is designed guaranteeing global exponential convergence of states to origin despite of parameter uncertainties, then the sliding-mode controller for the true force and torque inputs is derived to ensure that the actual surge and yaw velocities converge to the desired ones in finite time. The proposed control scheme is verified by simulation.