抄録
When a ship is required to maintain the specified position with high accuracy under influence of external disturbances, dynamic positioning system (DPS) is often used. The linear quadratic (LQ) optimal regulator theory is mainly applied to design control system of DPS. However, it is very complicated and difficult to select suitable weighting matrices in the performance index manually to obtain optimal control input. So, recently the inverse linear quadratic (ILQ) optimal servo theory has been proposed. In this method, it is able to design a control system which has no interaction among the state variables, and it is also able to express the optimal feedback gain in terms of the system matrices and the design parameters. In this paper, we applied the ILQ optimal servo theory to design the control system of DPS for a self-propulsive barge considering effects of heaving, rolling and pitching motion. In ILQ optimal servo theory, time constant T_i as the design parameters have much influence on the performance of the control system. From the numerical simulations, it is found that T_i should be selected as small as possible according to intensity of external disturbances, considering performance of the thruster.
