• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.1-7
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• 2003

When a ship is course-keeping in the open seas, autopilot system is adapted. The design of autopilot system is very important for improvement of ship′s element research. Automatic steering system consists of autopilot device, power unit, steering gear, magnetic or gyro compass and ship dynamics. In order to evaluate automatic steering system of ships in open seas. we need to know the characteristics of each component of the system, and also to know the characteristics of disturbance to ship dynamics. In this paper, I provide evaluation method of autopilot navigation system of the fishing ship. Prediction method based on the principle of linear superposition is introduced for irregular disturbance. For the evaluation of automatic steering system of a ship, "performance index" is introduced from the viewpoint of energy saving and calculation method is frequency response analysis. Finally, I carried out calculation of sensitivity of control constants of autopilot with various conditions of ocean environments.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.990-995
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• 2010

We consider a problem of intelligent Integration Information system for research ship, and propose a design as one effective solution of the problem. The goals of the proposed design and system are as follows: management of engine, management of ship, researcher's work, education, training, manage schedule of the project, and thus to manage the whole life cycle of the research ship project. These goals are basically to facilitate and implement innovation- and enhancement-related activities which intelligent Integration Information system is fundamentally pursuing.

• Journal of Hydrospace Technology
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• v.1 no.1
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• pp.41-56
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• 1995

Flew control devices, such as flow liners, are frequently introduced in a cavitation tunnel in order to reduce the tunnel blockage effect, when a three-dimensional wake distribution is simulated using a complete ship model or a dummy model. In order to estimate the tunnel wall effect and to evaluate the effect of flow liners on the simulated wake distribution, a surface panel method is adopted for the calculation of the flow around a ship model and flow liners installed in a rectangular test section off cavitation tunnel. Calculation results on the Sydney Express ship model show that the tunnel wall effect on the hull surface pressure distribution is negligible for less than 5% blockage and can be appreciable for more than 20% blockage. The flow liners accelerate the flow near the afterbody of the ship model, so that the pressure gradient there becomes more favorable and accordingly the boundary layer thickness would be reduced. Since the resulting wake distribution is assumed to resemble the full scale wake, flow liners can also be used to simulate an estimated full scale wake without modifying the ship model. Boundary taper calculation should be incorporated in order to correlate the calculated wake distribution with the measured one.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.185-192
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• 2016

Low operational cost and high efficiency is absolute requirements in the mass production of the ship engine. Increasing the performance of the fuel injection system in the diesel engine is one kind of solution to improve the efficiency. Modern diesel engines are using electronic control module as the main controller in the fuel injection control system, however the mechanical system still involved in the modern control system. In modern ship engine, a control valve was used in injection fuel to regulate the flow of the fuel. High pressure and friction are intensively occur within this part, therefore high wear resist and low friction coefficient material including fine lubricating are needed. This study is to figure out the wear resist material and proper lubricant in the control valve fuel injection. The experiment has been tested using pin on disk in several treatments those are used various lubricants and non-lubricant condition. Two kinds of lubricant were used in this experiment such as INDERIN AW-32 and paraffin oil. INDERIN AW-32 has a better result compared to non-lubricant condition, which are 20% performance increases than non-lubricant condition. SCM 440 was providing small friction coefficient in the lower velocity. The friction coefficient was constantly maintains at 0.1 m/s of velocity or above respectively with the increment of the loads. Using INDERIN AW-32 and paraffin oil the lowest friction coefficient occurred at the lower load, and increases side by side with the increment of loads.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.150-153
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• 1995

In this paper the attitude control system is developed for longitudinal motion of Foil-Catamaran in regular waves with all-movable foils which attached to fore and after part of the ship and verified the system by theoretical calculation and model-tests. The linearized equations of motion of the ship is employed to apply the linear control theories, the PID control and the LQR. The strip method was used to calculate hydrodynamic coefficients and wave exciting forces of the demi hull, and unsteady hydrodynamic forces of foils are considered by using the result of Wu(1972). About 40-60% of motions is reduced in experiments. The control system described in this paper is able to extended to 6-DOF motions or control in irregular wave with trivial modification. And it is applicable to hull shape development for better seakeeping performance and to determine the size and the position of hydrofoils for the attitude control.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.444-449
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• 2001

There have been many accidents of passenger ships on the sea and they have caused a big loss of human lives. Maritime Safety Committee(MSC) of International Maritime Organization(IMO) made evacuation analysis of Ro-Ro passenger ships mandatory in order to save as many lives as possible at the time of accident. But this is a temporary regulation and HSC/IMO ties to introduce a performance-based regulation to improve the effect of regulation. Simulation-based evacuation analysis is the basis of performance-based regulation. In this paper, we performed a simulation-based evacuation analysis on a passenger ship, which is usually used in the plying between land and islands in Korea, with EXODUS system. Through inspecting the results from this analysis in more detail, we can make a proposal to improve the safety of passenger ship. Finally we describe the features of IMEX(Intelligent Model for Extrication Simulation), a new evacuation model being developed in KRISO.

• Journal of the Korean Institute of Navigation
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• v.25 no.1
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• pp.33-44
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• 2001

Tankers have somewhat different shapes in construction and working condition compared with normal merchant ship. If an accident occurs, normal merchant ship's damages will mostly be confined to ship and cargo, but those of tankers will result in oil spills and catastrophic loss beyond our imagination. So, first we must understand risk factors, pre-loss control and post-loss control, legal regulations about its indemnification and marine insurance for oil tanker operation. When unexpected accidents happen, despite pre-loss control, it is possible to cover those kinds of losses by insurance. To control these losses, however, it is important to establish compensation for oil pollution and arrange for oil pollution preventing system. In spite of these oil pollution preventing systems, we have rarely seen that pollution from oil tankers could be solved. So this paper was studied more fundamental and overall control measures for the risk management of oil tanker operation.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.380-387
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• 2011

In this paper, we considered the authoritative representation of Command and Fire Control System(CFCS) for the surface ship that was the engineering level model to develop system specifications and to analyze operational concepts on the concept design phase and to analyze military requirements, effectiveness and performance for the system. The engineering level model of CFCS can be used in simulation independently of the surface ship's type, and also it takes reuse, interoperability, and extension into consideration. The detailed sub-models, internal and external data interface, data flow among each sub-model, sensor and weapon models about the engineering level model of CFCS was defined. It was verified via engineering level simulations according to the V&V process.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.3
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• pp.199-210
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• 2012

The recent researches on the automatic berthing control problems have used various kinds of tools as a control method such as expert system, fuzzy logic controllers and artificial neural network (ANN). Among them, ANN has proved to be one of the most effective and attractive options. In a marine context, the berthing maneuver is a complicated procedure in which both human experience and intensive control operations are involved. Nowadays, in most cases of berthing operation, auxiliary devices are used to make the schedule safer and faster but none of above researches has taken into account. In this study, ANN is applied to design the controllers for automatic ship berthing using assistant devices such as bow thruster and tug. Using back-propagation algorithm, we trained ANN with set of teaching data to get a minimal error between output values and desired values of four control outputs including rudder, propeller revolution, bow thruster and tug. Then, computer simulations of automatic berthing were carried out to verify the effectiveness of the system. The results of the simulations showed good performance for the proposed berthing control system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.38-46
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• 2021

In the era of the 4th Industrial Revolution, the interest in autonomous ship technology is increasing as high-tech technologies are being increasingly utilized throughout the industry. Therefore, we conducted a basic study on autonomous ships. In particular, a passenger ship model was produced and an autonomous navigation system was established by applying the ardupilot used for drones. The possibility of automatic control of the autonomous ship operations was confirmed by executing various voyage plans using the built model ship. In the performance test for maintaining the course the model ship could not follow the designated course straight and sailed up to 5.4 m away from the course while navigating in a zigzag (S-shape); however, after the parameters were modified, the deviation distance was reduced to a maximum of 1.8 m. In the turning performance test, the maximum diameter of the turning sphere was found to be approximately 9.3 m, but no significant change could be confirmed even after the parameters were modified. However, the results of our tests on slowing down the ship before arriving at the WP confirmed that the diameter of the turning sphere was reduced to a maximum of approximately 3.2 m. In order to evaluate the stopping performance, the last scheduled stopping position of all experiments was compared with the actual stopping position of the model ship and it was confirmed that the model ship stopped at a point at least 0.4 m and a maximum of 6.2 m away from the stopping position. In the future, improvement of course stability, turning performance, and stopping performance is required through modification and supplementation of various parameters. Moreover, a study on automatic berthing of the model ship through automatic control is planned.