• 한국항해항만학회지
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• 제38권5호
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• pp.463-470
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• 2014

본 논문에서는 선박의 예인에 필요한 예인력의 계산과 이를 검증하기 위한 실험 결과에 대해 언급하고 있다. 먼저 예인력의 계산에 있어서는 선박의 마찰저항, 풍압저항, 조파저항을 고려하였다. 아울러 프로펠러가 고착된 상태를 가정하여 프로펠러 저항을 계산하였다. 이와 더불어 예인 시 사용되는 예인삭에 걸리는 부가저항을 노드분석법을 적용하여 계산하였고, 선체 저항과 예인삭에서의 부가저항을 합하여 최종적인 예인저항을 도출하였다. 계산된 결과값의 유효성을 검증하기 위하여 목포해양대학교 실습선 새유달호를 활용하여 해상에서 예인실험을 수행하였고 이론적인 계산 결과와 실험 결과에 대한 비교를 행하였다. 소요 예인력의 이론적인 계산에서 주요한 요소는 예인속력임을 알 수 있었고, 예인속력의 증가에 따라 프로펠러 고착 저항이 저항의 주요한 부분을 차지하는 것을 확인하였다. 실제 실험을 통해서는 선박의 요잉에 의한 저항 증가분을 고려하는 것이 필요하다는 것을 알 수 있었다.

• 한국해양공학회지
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• 제36권1호
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• pp.50-60
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• 2022

The deep ocean engineering basin (DOEB) of the Korea Research Institute of Ship and Ocean Engineering (KRISO) is equipped with an extreme-environment reproduction facility that can analyze the motion characteristics of offshore structures and ships. In recent years, there have been requirements for a wide range of six-degree-of-freedom (6-DOF) motion measurements for performing maneuvering tests and free-running tests of target objects (offshore structures or ships). This study introduces the process of developing a wide-area motion measurement technology by incorporating the auto-tracking technology of the towing carriage system to overcome the existing 6-DOF motion measurement limitation. To realize a wide range of motion measurements, the automatic tracking control system of the towing carriage in the DOEB was designed as a speed control method. To verify the control performance, the characteristics of the towing carriage according to the variation in control gain were analyzed. Finally, a wide range of motions was tested using a model test object (a remotely operated vehicle (ROV)), and the wide-area motion measurement technology was implemented using an automatic tracking control system for a towing carriage.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.943-956
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• 2020

In this study, the motion control problem of the vessel towed by a towing ship (tugboat) is considered. The non-powered towed ship is dragged by the towing ship. Even though the towed ship is equipped with propulsion systems, they cannot be used at low or constant speeds due to safety issues. In narrow canals, rivers, and busy harbor areas especially, where extreme tension is required during towing operation, the course stability of the towed vessel depends on the towing ship. Therefore, the authors propose a new control strategy in which the rudder system of the towed vessel is activated to provide its maneuverability. Based on the leader-follower system configuration, a nonlinear mathematical model is derived and a back-stepping control is designed. By simulation and experiment results with a comparison study, the usefulness and effectiveness of the proposed strategy are validated.

• 한국해양환경ㆍ에너지학회지
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• 제17권4호
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• pp.318-323
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• 2014

해상에서 사고선박을 예인하기 위해서는, 예상되는 바람과 조류 등의 해상상태에서, 선정된 예인선들의 예인력과 예인방향을 이용하여 피예인선의 선속과 방향을 추정하여야 한다. 본 논문에서는 사고선박의 다양한 예인계획에 따른 예인상태 추정 방법을 연구하였다. 기존 전산 프로그램을 사용하여 계산된 피예인선의 정면방향 선속과 저항을 가져오는 방법과, 초기 예인상태에서 선정된 예인선들에 의한 피예인선의 전진방향 선속과 저항을 계산하는 방법, 그리고 안정된 예인상태에서 피예인선의 전진방향 선속과 저항을 계산하는 방법을 제안하였다. 이들 계산 방법은 전산 프로그램으로 구현되었으며, 이 프로그램은 피예인선의 상태를 적절히 추정할 수 있는 유용한 프로그램으로 확인되었다.

• 해양환경안전학회지
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• 제19권6호
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• pp.637-642
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• 2013

본 연구는 피예인선의 거동을 결정짓는 예인선의 힘과 작용지점의 해석에 대해 언급하고 있다. 예인대상선박의 간략화된 동역학방정식을 바탕으로 선형화기법을 적용하여 목적으로 하는 피예인선의 자세와 위치를 달성하기 위한 예인력과 예인력이 가해져야 하는 지점을 도출하였다. 이를 위해 LQR제어기법을 적용하였으며, 수치적인 시뮬레이션을 수행하였다. 리카치방정식을 이용하여 피예인선의 자세제어를 위한 제어기 이득과 자세제어에 필요한 무게중심에서의 힘을 도출하였고, 도출한 힘과 예인지점의 역학적인 관계는 의사역행렬을 이용하여 구하였다. 이러한 해석기법을 바탕으로 피예인선을 초기위치로부터 목표위치로 예인할 때 예인지점 및 예인방식에 따른 예인력을 구할 수 있었다. 최종적으로 선박을 예인하기 위한 예인력은 예인지점과 방향에 밀접하게 연관되어 있는 것을 확인할 수 있었고 이러한 연구결과는 사고선박의 구난작업 시 예인선의 배치에도 적용이 가능할 것이다.

• 한국해양공학회지
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• 제33권5호
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• pp.462-469
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• 2019

In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessels, such as barge ships, are used for several purposes. Generally, these vessels have no power propulsion system and are towed using ropes and towing vessel (tugboats). The basic mathematical model of the towed vessel in which three active rudders are attached was introduced from a previous study. Owing to the dependency of the motions of the towed vessel to the towing ship, a method is suggested to cope with the undesirable disturbance and improve the tracking performance. For the simulation study, a model of the towed vessel with a towing ship is made, and necessary physical parameters are identified from the experiment. For the defined and linearized model, a control system is designed, and the control performance is also evaluated. A simulation study is conducted and the effectiveness of the proposed control strategy is verified.

• 대한조선학회논문집
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• 제51권5호
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• pp.349-355
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• 2014

The resistance test of a high speed craft such as planing ship is performed with a high speed towing carriage instead of ordinary towing carriage because of the speed limitation. In the resistance test using high speed towing carriage, the model ship is fixed to the carriage to restrain the running attitude for enough measuring time. Such method is called fixed model test method. In the fixed model test method, to get the appropriate running attitude, the model test is iteratively repeated until the trim moment and lift force are close to zero. In this research, trim free model test method is investigated to reduce the number of iteration. And, the limitation of towing speed range in the trim free model test method is investigated.

• 수산해양기술연구
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• 제59권4호
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• pp.344-353
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• 2023

In the actual sea, the additional resistance due to external force such as wind, current and wave is accompanied, and the required power is added in response to these resistance. Especially when the ship is sailing at low speed, the effects of wind and current have a great impact on the safe control of the ship. Likewise, it is thought that the effects of wind and current have a great impact on the trawl ship control since the towing speed of a bottom trawl ship is a low speed of 3 to 4 knots. If the reduce of ship speed and the increase of engine power due to the influence of wind and current can be identified, the safe towing power can be calculated based on a given engine output. Thus, the appropriate size of a fishing gear can be determined. In this study, a total of 20 trawl operations were conducted for seasonal maritime research in the same research area according to the operation mode of propeller. Based on navigation data, trawl fishing data, and engine performance data acquired during the towing fishing gear, and data of ship speed, hull resistance, fishing gear resistance, wind force and current force according to an incidence angle were estimated. The overall power for these loads was calculated and compared with the measured engine power, and the effects of wind force and current force on the engine power were investigated.

• 수산해양기술연구
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• 제56권3호
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• pp.238-245
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• 2020

In this study, a motion control problem for the vessel towed by towing ship on the sea is considered. The towed vessel does not have self-control capabilities such that its course stability totally depends on the towing ship. Especially, in the narrow canal, river and congested harbor area, extreme tension is required during the towing operation. The authors, therefore, propose a new control system design method in which the rudder is activated to provide its maneuverability. Based on the leader following system configuration, a nonlinear mathematical model is derived and a backstepping control is designed. By experiment results with nonlinear control framework, the usefulness and effectiveness of the proposed strategy are presented.

• 수산해양기술연구
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• 제41권3호
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• pp.227-233
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• 2005

In order to estimate the effective horse power(EHP) in towing net of a bottom trawl ship, the ship's resistance was calculated by using a series data of Yamagata and Wigley formula. Also the effective horse power for a ship(EHPs) was estimated versus the ship speed in sailing and the propulsive efficiency was calculated with the brake horse power and the effective horse power. Then the effective horse power for a ship and a trawl net were estimated in the application of the propulsive efficiency in towing net. The total effective horse power($EHP_T$) was average 187.6kW and the effective horse power for a 1.awl net($EHP_n$) was average 176.7kW at a smooth sea state in towing net. The ratio of $EHP_n$ to $EHP_T$ was about 94.0% and the value was higher slightly than was already informed at a smooth sea state. The power for keeping up a townet speed was required more about 20% of a maximum continuous power at a rather rough sea state than a smooth sea state. In the future, if the residual resistance is considered with a sea state, $EHP_n$ will be estimated more correctly Also the data of EHP estimated by this method will be used as the basic data to design a trawl net.