INTEGRATED TRAJECTORY PLANNING AND TRACKING CONTROL OF UNDERACTUATED SURFACE VESSELS

A novel nonlinear trajectory tracking controller for underactuated unmanned surface vessels is presented. A comprehensive planar model of the vessel with two control inputs is considered such that the system is represented by the equations of motion comprised of two double integrators subject to a second-order nonholonomic constraint. Given a target trajectory, a transitional desired trajectory is generated that uniformly satisfies the nonholonomic constraint and actuator saturation constraints. The system error dynamics is then modeled using the equations of motion and the transitional desired trajectory. A finite time sliding mode control law is developed to stabilize the yaw rotation which is robust to model uncertainties and disturbances. Consequently, the resulting reduced-order system is asymptotically stabilized via the surge force. Examples are presented and demonstrate that the approach provides trajectories and tracking control inputs which are suitable for real world applications.