Optimal Control of Dynamic Positioned Vessel Using Kalman Filtering Techniques

J. Ocean Eng. Technol. 1988;2(2):37-45.

Lee Pan-Muk,Lee Sang-Mu,Hong Sa-Yeong

칼만필터를 이용한 부유체운동의 최적제어

이판묵,이상무,홍사영

한국기계연구원 대덕선박분소 해양기술실,한국기계연구원 대덕선박분소 해양기술실,한국기계연구원 대덕선박분소 해양기술실

Keywords: Dynamic Positioning System, Kalman Filter, Optimal Control, LQG Controller, Shaping Filter, Motion Estimate

핵심용어: 자동위치확보장치, 칼만필터, 최적제어, LQG 제어기, 형상필터, 운동추정

Abstract

A dynamically positioned vessel must be capable of maintaining a specified position and direction by controlling the thruster devices. The motions of a vessel are often assuned to tne sum of low frequency(LF)motions and high frequency(HF)motions. The former is mainly due to wind, current and second order wave forces, while the latter is mainly due to first order wave forces. In order to avoid the high frequency thruser modulation, the control system must include filters to estimate the low frequency motions from the measured motion signals, This paper presents a control system based on Kalman filtering technique and optimal control tyeory. Using the combined kalmam filter, LF motion estimates and HF ones are achieved from the motion measurement of the vessel. The estimated low frequency motions are used as inputs to the dynamic positioning system. The thruster modulation is minimized using the optimal control theory; Linear Quadratic Gaussian(LQG)controller. The performances of the Kalman filter and the dynamic positioned vessel are investigated by computer simulation.