Robust H? Control for Sampled-data Dynamic Positioning Ships

Abstract

This study is concerned with the robust H_? sampled-data control problem for dynamic positioning (DP) ships. Using the input delay approach, the ship dynamic positioning (DP) system is converted to a time-varying delay system. Sufficient conditions were then established to make the system exponentially stable with prescribed H_? performance using Lyapunov stability theorems. Then, the H_? sampled-data controller is obtained by means of linear matrix inequalities to guarantee that the DP ships can maintain the desired position, heading and velocities. Simulation result is shown that the proposed method and the designed controller for DP ships are effective in the existence of varying environment disturbance.