Virtual guide control for underactuated surface ships

To solve the stabilization problems of underactuated surface ships with nonintegrable acceleration constraint, a novel virtual guide control algorithm is presented. The control method is both descriptive and constructive. By introducing an autonomic virtual system, the nonholonomic stabilization can be transformed into control problems of holonomic and full actuated subsystems. Using decoupling control method and iterative nonlinear sliding mode designing approach integrated with simple increment feedback control laws, a dynamic control strategy is developed to fulfill the underactuated stabilization objectives. Numerical simulation results on a full nonlinear hydrodynamic model of a training ship are presented to validate the effectiveness and robustness of the proposed controller.