A Study on Simple Dynamic Positioning System based on Weather Vaning

摘要

In this study, we investigate the property of simple Weather Vaning Dynamic Positioning system (WV-DP system). This DP system is the combination of feedback control of controllable pitch propeller (CPP) of the main engine and the feedforward control of side thruster. The system has the automatic weather-vaning properties of the heading of the ship but the property of the positioning is depending on the configuration of thruster on the hull. Based on the very simple idea that the “Normal Pendulum (NP)” system is more stable in the control of its orientation than the “Inverted Pendulum (IP)”, we recommend the new configuration NP-type WV-DP system in which the stern of the hull is toward the direction of disturbances. Extensive simulations were carried out using the detailed non-linear mathematical model of the training hipShioji Maruof the Tokyo University of Marine Science and Technology under various conditions. As a result, we can confirm that the control performance of NP-type WV-DP system is improved under many conditions by comparing with IP-type (conventional) WV-DP system.