• Journal of Navigation and Port Research
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• v.47 no.2
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• pp.66-74
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• 2023

With the increase of interest in developing Maritime Autonomous Surface Ships (MASS), an optimal ship route planning is gradually gaining popularity as one of the important subsystems for autonomy of modern marine vessels. In the present paper, an optimal ship route planning model for MASS is proposed using a nonlinear MPC approach together with a nonlinear MMG model. Results drawn from this study demonstrated that the optimization problem for the ship route was successfully solved with satisfaction of the nonlinear dynamics of the ship and all constraints for the state and manipulated variables using the nonlinear MPC approach. Given that a route generation system capable of accounting for nonlinear dynamics of the ship and equality/inequality constraints is essential for achieving fully autonomous navigation at sea, it is expected that this paper will contribute to the field of autonomous vehicles by demonstrating the performance of the proposed optimal ship route planning model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.559-562
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• 1995

In the crane control system, it is reguired that the travelling time of the crane must be reduced as much as possible and the swing must be stoped at the end point. In paper, we present a hybrid control method which include the optimal regulator and velocity pattern controller in order to make high performance of the anti-sway. To implement the control algorithm, the dynamic equation is linearlized at an equilibrium point, so that the liner time invariant state equation can be obtained. In order to experiment the crane control, we consider 1 over 10 of the gantry crane which is used in a port. As a result, the hybrid control method improve efficient anti-sway control more than conventional velocity pattern control. It is expected that the proposed system will make an important contribution to the industrial fields.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.129-137
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• 2006

This paper studies the effects of the swirl for the variation of intake port configuration that is key parameters in the flow field of direct injection diesel engines. In-cylinder flow characteristics is known to have significant effects on air-fuel mixing, combustion, and emissions. To investigate the effects of the swirl flow, various rpm(250, 500, 750) and two different intake port were used. And to evaluate the swirl motion in the flow field visualization engine, steady state flow test was conducted. Helical port intake port and SCV(Swirl Control Valve) were selected as the design parameters to increase the swirl flow and parametric study was performed. In the case of non-SCV, intake flow rate and non-dimensional swirl ratio were higher than those of SCV for the swirl head type. So, we could strengthen the swirl in the flow field with the swirl head type and don't using SCV. From the results of steady state flow test, non-swirl head type has the most good advantage for intake flow rate, and also the flow rate could be increased by using the SCV slightly. The effects of the type of engine head on intake air flow capability are dominant with respect to the existence of the SCV. We could measure the qualitative grade of swirl by capturing the scattering signal of microballoon from ICCD camera in the visualization diesel engine.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.383-384
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• 2010

The control surface on a ship is to control the motion of it in forward and backward states. In this paper, the measured results has been compared with each other to predict the backward flow characteristics of the single rudder's 2-dimensional section at $Re=2.0\times10^4$ using 2-frame grey level cross correlation PIV method especially, The separation region appears at 10 to 20 degrees angle of attack in a forward state. The separation point and boundary layer demonstrate in the same angle of attack compared it with the forward states.

• Journal of Navigation and Port Research
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• v.35 no.2
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• pp.121-130
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• 2011

The localization of vehicle is an important part of an unmanned vehicle control problem. Pseudolite ultrasonic system(PUS) is the method to find an absolute position with a high accuracy by using ultrasonic sensor. And Gyro is the inertial sensor to measure yaw angle of vehicle. PUS can be able to estimate the position of mobile robot precisely, in which errors are not accumulated. And Gyro is a more faster measure method than PUS. In this paper, we suggest a more accuracy method of calculating PUS which is numerical analysis approach named Newtonian method. And also propose the fusion method to increase the accuracy of estimated angle on moving vehicle by using PUS and Gyro integrated system by Kalman filtering. To control the 4WS unmanned vehicle, the trajectory following algorithm is suggested. And the new concept arbitration of goal controller is suggested. This method considers the desirability function of vehicle state. Finally, the performances of Newtonian method and designed controller were verified from the experimental results with the 4WS vehicle scaled 1/10.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.459-464
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• 2008

In this paper, we present the model-based fuzzy controller for container cranes which effectively performs set-point tracking control of trolley and anti-swaying control under system parameter and disturbance changes. The first part of this paper focuses on the development of Takagi-Sugeno (T-S) fuzzy modeling in a nonlinear container crane system. Parameters of the membership functions are adjusted by a RCGA to have same dynamic characteristics with nonlinear model of a container crane. In the second part, we present a design methodology of the model-based fuzzy controller. Sub-controllers are designed using LQ control theory for each subsystem in fuzzy model and then the proposed controller is performed with the combination of these sub-controllers by fuzzy IF-THEN rules. In the results of simulation, the fuzzy model showed almost similar dynamic characteristics compared to the outputs of the nonlinear container crane model. Also, the model-based fuzzy controller showed not only the fast settling time for the change in parameter and disturbance, but also stable and robust control performances without any steady-state error.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.366-374
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• 2013

Maritime transportation circumstance is changing rapidly in accordance with the increase of cargo volume between countries and increase of marine leisure activities by improvement of quality of life. And the circumstance for ship operation is also changing due to aging of seafarers and increasing of foreign seafarers. To cope with such changes in maritime environment well, it requires higher safety management skills from shipping companies, the main subject in charge of the safety matter. In this paper, we analyzed domestic and foreign similar system, and then applied imitation strategies for introduction of an unific evaluation and management system that was consist of marine accidents, port state control, ISM Code and so on from shipping companies. We defined that the imitation industry and system are converted accident ration of construction industry and traffic safety excellence company of road transportation, and then extracted relevant law, evaluation index, incentive system as a imitation subject. We also proposed scheme that introduction of basis law, and evaluation tool with marine accidents ratio, port state control & ism code result, and incentives such as immunity of safety inspection or reduction of commission for introduction of company's safety management level evaluation system. Finally, we proposed the imitation timing and plan in stages for system's sustainable development through the prompt introduction and continuous enforcement.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.671-676
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• 2014

Based on the data of PSC information management system of MOF(Ministry of oceans and fisheries) and APCIS(Asia-Pacific Computerized Information System) of Tokyo-MOU information system, the result of the evaluation on the reality of PSC was done, and base on 2009, it showed a trend of decrease in every DFR(Deficiency Rate) and DTR(Detention Rate). But for vessels built for more than 30 years, flags of convenience vessels, RO-RO ferry and general cargo vessel, small size vessels with gross tonnage less than 1,000 ton showed a high DFR and DTR. Each harbours is classified by the total harbours' average DFR which was 82.5 % and the average DTR was 5.1 %, excluding the Jeju harbour, showing a hugh deviation for classification of each harbour. Classification of each harbour has to be inspected by PSC and it showed a great unbalance of the number of vessels for each territory for inspection. the biggest problem with our country's PSC, where it was pointed out by the PSCO was lack of workers and independent inspection by just one worker. To strength the substantiality of the inspection of our country is to have concentrated inspection on the high risk cautious vessels, forming a human network each classified by four different sectors of the area, recalculating the amount of assignment of inspection classified by each harbour and securing workforce the PSCO improvements are necessary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.18-26
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• 2019

The Maritime Labour Convention, 2006, (MLC) aimed to ensure decent working conditions for seafarers and entered into force on August 20, 2013. It was considered as the fourth pillar in the maritime sector. This paper evaluates how the MLC has been implemented in the field and what issues were addressed in the shipping industry. To achieve this, statistical analysis was conducted using inspection data of Port State Control (PSC) carried out by the Paris MOU and the Tokyo MOU during 2010-2012 and 2014-2016 for deficiencies under the MLC and International Labour Organization (ILO) No. 147 Convention. This study compared pre-2013 and post-2013 deficiency data according to ship's age, size (gross tonnage) and type. The results showed that, although the deficiencies reported by the Tokyo MOU during 2014-2016 were nearly double those from 2010-2012, the deficiency share against total deficiencies for the Tokyo MOU remained two thirds of those for the Paris MOU. This study suggests that the Tokyo MOU should strengthen its inspection efforts on MLC and ILO should provide clear references, such as guidelines and a unified interpretation for national discretions under the MLC for the purpose of harmonized PSC inspections. Additionally, it would be desirable to consolidate the deficiency coding system for the MLC by deleting the codes for the ILO No. 147 Convention, which was incorporated into the MLC. It would also be beneficial to add new deficiency codes for social security, including seafarers' leave and repatriation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.97-101
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• 2011

Quad band p-HEMT SP6T switch for handset applications was developed. To achieve the low insertion loss and high isolation, trade-off between "On" state and "Off" state was considered by optimization of unit cell. Especially, in case isolation between transmit port and receive port, it was achieved by large capacitors and miniaturization of chip size was achieved by common voltage control and ground using back via process. Designed SP6T switch has size of $950um{\times}100um$ and take into consideration the gate recess error, excellent loss and isolation was confirmed in operating frequency.