Robust stabilization of ship roll by convex optimization

For ship roll stabilization, this paper presents a nonlinear robust controller design method using the sum of squares (SOS) technique combined with the dual of Lyapunov´s stability theorem. Varying ship speed and initial metacentric height are seen as uncertainties, sea waves are regarded as external perturbations, and then the robust nonlinear controller is also designed based on the suggested method. Simulations are performed by taking container ship model as an example. It is shown that it makes the designed system guarantee the performance of robustness with respect to the uncertainties and perturbations.