In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessel looks like the barge ship, which is used for many purposes. In these vessels, basically, the power propulsion system is not installed but just towed by a towing vessel such as tugboats with ropes and wires. It means that the motions of towed vessel are basically dependent on the tracking route of towing boat. Therefore, in some cases, undesirable and unpredictable motions may be made by environmental factors such as wave, wind attack and so on. As a result, a collision accident with others may occur during maneuvering situation. Based on these facts, the authors try to encourage the steering performance of the towed vessel by using controllable rudders without any propulsion system. In this study, especially, a controllable vessel with three rudders is considered, and a mathematical model is induced for the future study. The model is described as surge, sway motion and inertia moment by following the general representation method for the surface ship.

서 론
 재료 및 방법
  제어대상의 포괄적 표현
  러더운동으로 발생하는 힘의 해석
  선형화 및 선형모델
 결과 및 고찰
 References

• 트란덕권(부경대학교 대학원 기계시스템공학과) | Duc-Quan TRAN (Department of Mechanical System Engineering, the Graduate School, Pukyong National University)
• 이동훈(부경대학교 대학원 기계시스템공학과) | Dong-Hun LEE (Department of Mechanical System Engineering, the Graduate School, Pukyong National University)
• 김태완(부경대학교 대학원 기계시스템공학과) | Tae-Wan KIM (Department of Mechanical System Engineering, the Graduate School, Pukyong National University)
• 김영복(부경대학교 기계시스템공학과) | Young-Bok KIM (Department of Mechanical System Engineering, Pukyong National University)
• 박환철(부경대학교 실습선) | Hwan-Cheol PARK (Training Ship Kaya, Pukyong National University) Corresponding author