• Bulletin of the Society of Naval Architects of Korea
• /
• v.21 no.3
• /
• pp.35-42
• /
• 1984

In this paper, the lateral motions of a ship in the time domain are treated by applying the Impulse Response Function Technique. The acceleration, and displacement of a ship in the time domain are needed for the purpose of such automatic controls as the fire control system and the auto-pilot of ocean-going vessels, etc. The response Amplitude Operators of a ship are calculated by the Strip Method of Salvesen-Tuck-Faltinsen, and the Pierson-Moskowitz Spectrum multiplied by spreading function is used to represent the short crested ocean waves. The ocean wave elevations in the time domain are simulated according to the Method of Borgman. Finally the rudder effect is considered by simply adding the force and moment due to the rudder to the wave exciting force. And the results of lateral motions with and without rudder are shown.

• Journal of Navigation and Port Research
• /
• v.46 no.5
• /
• pp.400-408
• /
• 2022

Maritime transportation is one of the most complicated and hazardous business fileds. Maritime accidents still occur despite several precautions since maritime is exposed to natural factors more than any other industries. In this harsh environment as a part of their job, marine pilots often embark/disembark to/ from vessels and confront life-endangering personal accidents. In the maritime field, several risk assessments are applied. However, all of them could not evaluate occupational accident risk for maritime pilot specifically. This paper performs specific risk analysis using the bow-tie method based on past accident records. This paper aims to qualify root causes and quantify root causes by importance level according to occurrence probability. As a result of analysis, occupational accident occurrence probability is found to be 14%, indicating that accident occurrence rate is significantly high. Hence, the probability of root causes triggering accidents and accident occurrence probability can be ascertained so that preventive measurements can be implemented. Besides theoretical achievement, this paper provides safety awareness to marine pilots, Marine Pilot Organizations, and ship crew who play a key role during marine pilots' transfer.

• Journal of Hydrospace Technology
• /
• v.1 no.1
• /
• pp.75-88
• /
• 1995

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship's direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dimension in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.

• Journal of Welding and Joining
• /
• v.14 no.6
• /
• pp.119-130
• /
• 1996

Welding is one of the important technologies in shipbuilding industry. Automation and productivity promotion of welding contribute to the cost saving of ship production. The quality and productivity of welding are dependent on the quality and suitability of technical information supplied by engineering parts. This paper describes the research results of welding information system for ship. The system can be used for the development of CIMS for shipbuilding. For this work, the welding information related to the ship Production were analyzed in detail. Object-oriented technique is applied to represent the complex and various welding information. To process the extend amount of the welding information of ship, database system was constructed. A pilot system for the bulk carrier ship was developed and can be used with ease by programming of event-driven method and implementaion of graphical user interlace.

• Journal of Navigation and Port Research
• /
• v.47 no.2
• /
• pp.75-84
• /
• 2023

Ships need to ensure safety during their navigation, which makes route determination highly important. It must be accompanied by a route following controller that can accurately follow the route. This study proposes a method for automatically generating the ship route based on deep reinforcement learning algorithm and following it using a route following controller. To generate a ship route, under keel clearance was applied to secure the ship's safety and navigation chart information was used to apply ship navigation related regulations. For the experiment, a target ship with a draft of 8.23 m was designated. The target route in this study was to depart from Busan port and arrive at the pilot boarding place of the Ulsan port. As a route following controller, a velocity type fuzzy P ID controller that could compensate for the limitation of a linear controller was applied. As a result of using the deep Q network, a route with a total distance of 62.22 km and 81 waypoints was generated. To simplify the route, the Douglas-Peucker algorithm was introduced to reduce the total distance to 55.67 m and the number of way points to 3. After that, an experiment was conducted to follow the path generated by the target ship. Experiment results revealed that the velocity type fuzzy P ID controller had less overshoot and fast settling time. In addition, it had the advantage of reducing the energy loss of the ship because the change in rudder angle was smooth. This study can be used as a basic study of route automatic generation. It suggests a method of combining ship route generation with the route following control.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.6 no.1
• /
• pp.1-9
• /
• 2000

The paper describes system design of next-generation Ship Simulator using Virtual Reality (VRSS), well known as human-computer interaction. VRSS system is required to have special condition that comprises multiple user participants such as captain, officer, pilot, and quartermaster. To cope with that condition, core technologies were explored and proposed multi-networking system with broker server. The evaluation of the proposed system was done with PC-based immersion-type VR device, constituted with HMD (Head Mounted Display), Head Tracking Sensor, Puck, Headphone, and Microphone. Using the VR device, assessment test was carried out in a virtual bridge with 3D objects, which are created by VRML (Virtual Reality Model Language) program. As results of tests, it is shown that the cybernetic 3D objects were act as if real things in a real ship's bridge. Therefore, interesting interaction with participants can be obtained in the system, Thus, we found that the proposed system architecture can be applicable to VRSS system construction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2019.11a
• /
• pp.107-108
• /
• 2019

In the past, regional pilot service is provided by individual pilots directly on board each ship, but it will be difficult to provide this type of service in the near future when autonomous vessels are activated. This can be seen as the need for automation and intelligence of pilot service and provision of remote control system. In this paper, we propose a method, system, and service target that can carry out the electronic pilot service through the intelligence aids to navigation for smart port operation.

• Journal of the Society of Naval Architects of Korea
• /
• v.30 no.4
• /
• pp.8-16
• /
• 1993

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dim in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.

• Proceedings of KOSOMES biannual meeting
• /
• 2004.05b
• /
• pp.107-112
• /
• 2004

In order to improve the safety r! ship berthing and the efficiency r! berth operation in the harbour, the berthing energy acting on a ship in berthing maneuver need to be estimated properly. The berthing energy is used as one q the criteria to determine the maximum permissible load of fender as well as important factors to establish the berthing speed and the required power r! tug-beat for pilot and ship operator. In this study, some problems r! present the method of berthing energy are discussed on the basis of the hydrodynamic aspects. Then, series calculations of berthing energy are carried out considering the effect of water depth on added mass and the ship shape for container series from 1,600TEU to 12,000TEU.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.2 no.1
• /
• pp.90-101
• /
• 1999

This paper is concerned with the design of automatic ship maneuvering system including automatic path tracking controller and automatic berthing controller. The optimal control technique is employed to design the automatic path tracking controller, which is based on the linearized equations of ship motion. The numerical example shows that the automatic path tracking controller is capable of tracking the line between way points which are determined by pilot a priori. The decentralized control technique is employed to design the automatic berthing controller. In addition to the automatic path tracking controller, the fuzzy logic controller is used to control the forward speed. The numerical example shows that the automatic berthing controller can be successfully implemented.