Turret 계류된 FSRU의 선수각 유지 제어에 관한 연구

Abstract

Floating storage and re-gasification unit (FSRU) is a new concept for floating offshore gas supplying plant units. FSRU has some benefits compared to onshore re-gasification plants like small environmental impact on seashore, high securities on neighborhood residence area and low initial cost. A turret moored FSRU concept was considered. It is well known that turret moored vessels tend to have fish tailing (or slewing) motion. This fish tailing motion may cause a considerable decrease in working time during re- gasification and gas loading process because of excessive roll motion, sloshing in the LNG containment tank, possible collision between FSRU and LNGC and also discomfort for the crew. In order to deal with these problems, a heading control system for turret moored FSRU is developed in this study. The heading control system is composed of motion estimator, controller and thruster system. Three azimuth thrusters are equipped on aft part of the vessel. In this study, Kalman filtering technique is applied, a PD controller and RMA (Resolved Motion and Acceleration) controller are used as a heading control algorithm for FSRU. And modified I controller is introduced to suppress steady state errors. An experimental study on heading control of FSRU was conducted in ocean engineering basin of KORDI.