Nonlinear sampled-data stabilization of dynamically positioned ships by reduced order observer-based controllers

Nonlinear sampled-data stabilization of dynamically positioned ships is considered using the nonlinear sampled-data control theory based on the Euler approximate model. First reduced order observers for the Euler approximate model of ships are designed. Then combining the designed observers and semiglobally practically asymptotically (SPA) stabilizing state feedback laws, reduced order observer-based SPA stabilizing output feedback controllers are derived. A numerical example is given to illustrate the design method.