ROBUST PERFORMANCE IN DYNAMIC POSITIONING SYSTEMS

Robust performance of dynamic positioning of surface vessels is consid ered. The structured singular value, mu, is used as a robustness measu re. A tight uncertainty description of the wave disturbance model and performance weight matrices based on physical insight is presented. Tw o controllers are analysed: a decentralized PD controller with notch f ilters and an LQG based controller. Performance of the control systems is shown to be sensitive with respect to changes in the dominating wa ve frequency, omega(0).