An application of guaranteed cost control in offshore steel jacket platforms

The guaranteed cost control (GCC) method with H_∞ disturbance attenuation is investigated for the steel jacket platform system when subjected to nonlinear self-excited hydrodynamic forces. A state feedback controller is designed to ensure the asymptotic stability of the steel jacket platform system. In the presence of self-excited wave forces, the proposed scheme satisfies H_∞ disturbance attenuation level and guarantees cost upper bound. By Lyapunov stability theory and linear matrix inequality (LMI) approach, a sufficient condition is given to ensure the existence of the guaranteed cost controller. Simulation results are presented to demonstrate the effectiveness of the proposed scheme.