Sliding mode trajectory tracking control of underactuated surface vessels

Aiming at the model parameters uncertainties in the trajectory tracking control of a 3 degrees of freedom (3DOF) underactuated surface vessel, a new nonlinear sliding mode control law is presented. According to the properties of underactuated surface vessels, the sway direction is not actuated, and for manoeuvring the vessel of 3DOF in surge, sway, and yaw directions, the sliding mode based controller is designed by introducing two sliding surfaces, one is the first order surface by surge following errors, the other is the second order surface by sway following errors. The efficacy of the tracking controller is explained through numerical simulations.