• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.585-598
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• 2021

The course-keeping stability of a high speed planing boat should be considered at the design stage for its safe operations. The shape of waterjet intake plane is one of important design parameters of a waterjet propelled planing boat. That has significant influences on the stern flow patterns and pressure distributions. In this study, the effects of the waterjet intake shapes of planing boats on the course-keeping stabilities are investigated. Two kinds of designed planing boats have the same dimensions, but there are differences in waterjet intake plane shapes. Captive and free-running model tests, Computational Fluid Dynamics (CFD) analyses are carried out in order to estimate their hydrodynamic performances including course-keeping stabilities. The results show that the flat and wide waterjet intake plane of the initially designed boat makes the course-keeping stability worse. The waterjet intake shape is redesigned to improve the course-keeping stability. The improved performances are confirmed by free-running model tests and full-scale trials.

• 한국해양공학회지
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• 제11권3호
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• pp.100-106
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• 1997

Despite various devices have been developed and applied to stabilize the yaw motion, the superiority of twin skeg over other equi-functioned appendages has been recognized so far. In many cases, these skegs were installed with insufficient study and analysis for design, and this leads to the worse performance of their resistance and course keeping than required. Experimental studies on the effect of various kinds of anti-yawing skegs to the course keeping stability and on the additional resistance caused by them were carried out in the circulating water channel(CWC) at Chosun University(CU). Course keeping stability tests for four different size of skegs, resistance tests for three different shapes of skeg(including deformed skegs) were performed systematically. And the effect of angle of skegs on resistance was studied at the final stage.

• 한국해양공학회지
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• 제13권1호통권31호
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• pp.18-22
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• 1999

One of the problem areas in designing a barge is its resistance and corese stability when it is towed by a tugboat. In this paper, as a part of design of a incinerating vessel, the results of some experimental studies on the effect of various kinds of anti-yawing skegs to the course keeping stability and on the additional resistance caused by them were summarized.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.720-723
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• 2005

Ship motion is a complex controlled process with several hydrodynamic parameters that vary in wide ranges with respect to ship load condition, speed and surrounding conditions (such as wind, current, tide, etc.). Therefore, to effectively control ships in a designed track is always an important task for ship masters. This paper presents an effective adaptive autopilot ships that ensure the optimal accuracy, economy and stability characteristics. The PID control methodology is modified and parameters of a PID controller is designed to satisfy conditions for an optimal objective function that comprised by heading error, resistance and drift during changing course, and loss of surge velocity or fuel consumption. Designing of the controller for course changing process is based on the Model Reference Adaptive System (MRAS) control theory, while as designing of the automatic course keeping process is based on the Self Tuning Regulator (STR) control theory. Simulation (using MATLAB software) in various disturbance conditions shows that in comparison with conventional PID autopilots, the designed autopilot has several notable advantages: higher course turning speed, lower swing of ship bow even in strong waves and winds, high accuracy of course keeping, shorter time of rudder actions smaller times of changing rudder direction.

• 한국해양공학회지
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• 제25권5호
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• pp.27-32
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• 2011

Recently, a ship-shaped barge has been developed to improve the resistance performance, as well as course-keeping capability. However, the stern of the barge is still similar to a box shape, and the vortex generated at the side of the barge creates drag and yaw instability. In order to solve this problem, stern skegs are normally used. The present paper deals with the correlation between the size of the stern skegs and the barge dimensions and hull coefficient. A stern skeg was designed to prevent yaw instability and minimize any additional resistance. The resistance test and course keeping test were performed in the towing tank at Pusan National University. To determine the correlation parameters between the designed stern skeg size and barge dimensions, a parametric study was also performed. Based on the experimental data from five barges, the optimum skeg dimensions were successfully derived. It is expected that the validation of the present study will be carried out by further experiments and computational comparisons in the near future.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.209-211
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• 2006

Auto Steering System is the device for course keeping or course altering to ship's steering system. The purpose of automatic steering system is to keep the ship's course stable with the minimum course and rudder angle. Recently, modern control theories are being used widely in analyzing and designing the ship system. Though P.D type auto pilots are widely used in ships, the stability and the adjusting methods are not clarified. In this paper the authors proposed auto steering system with Hybrid Controller. The things that the actual operators of a steering wheel has acquired through their experience can be logically described by the Lingustic Control Rule. The characteristic of the control system were investigated through the computer simulation results. it was found that the Hybrid control was more efficient than the PD control system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2671-2674
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• 2005

Auto Pilot System is the device for course keeping or course altering to ship's steering system. The purpose of automatic steering system is to keep the ship's course stable with the minimum course and rudder angle. Recently, modem control theories are being used widely in analyzing and designing the ship system. Though P.I.D type auto pilots are widely used in ships, the stability and the adjusting meyhods are not clarified. In this paper the authors proposed auto pilot system with Fuzzy Logic Controller. In the fuzzy control the things that the actual operators of a steering wheel has acquired through their experience can be logically described by the Lingustic Control Rule. The characteristic of the control system were investi gated through the computer simulation results. it was found that the fuzzy logic control was more efficient than the conventional system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.114-117
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• 2005

Auto Steering System is the device for course keeping or course altering to ship's steering system. The Purpose of automatic steering system is to keep the ship's course stable with the minimum course and rudder angle. Recently, modern control theories are being used widely in analyzing and designing the ship system. Though P.D type auto pilots are widely used in ships, the stability and the adjusting methods are not clarified. In this paper the authors proposed auto steering system with Fuzzy Logic Controller. In the fuzzy control the things that the actual operators of a steering wheel has acquired through their experience can be logically described by the Lingustic Control Rule. The characteristic of the control system were investigated through the computer simulation results. it was found that the fuzzy logic control was more efficient than the conventional system.

• 대한조선학회논문집
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• 제47권4호
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• pp.496-507
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• 2010

It is well known that when a high-speed planing craft travels in following seas it experiences long-periodic motions due to low encounter frequency, and it often loses its course keeping stability. Therefore, it is necessary to study the sea-keeping performance and stability of it in the following seas. In this paper, the vertical motions of a planing craft were measured in following regular waves, and the test results were compared with the theoretical results. In the case of the same encounter frequency, non-dimensionalized motion amplitudes become larger as Froude number is higher, and non-dimensionalized motion amplitudes in head waves are larger than those in following waves. The mean values of the motions in following waves are similar to the running attitudes of a craft in calm water at the same Froude number.

• 대한물리의학회지
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• 제3권2호
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• pp.121-125
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• 2008

Purpose : The objective of this study was conducted to find out the treatment of joint problems. Methods : This is a literature study with books, seminar note and international course books. Results : Passive oscillation and distraction movement therapy is only joint mobilization and pain control. In the joint therapy need muscle strengthening, training of eccentrical control and neurophysiological therapy for joint mobility, stability, stability of mobility and skill. Conclusion : Joint therapy is not only joint mobility but also strengthening of soft tissue. Need the neurophysiological therapy those are use of ventromedial motor nucleus and dorsolateral motor nucleus, reciprocal inhibition, eccentrical muscle contraction training, proprioceptors and exteroceptor for structures and functional activities. For the pain control, reduce swelling, keeping GAGs and functional activities need direct and indirect therapy.