• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.263-268
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• 2001

In this paper, we present a new heuristic algorithm fur buffer allocation in FMS (Flexible Manufacturing System). It is conducted by using a genetic algorithm and simulation. First, we model the system by using a simulation software, \"Arena\". Then, we apply a genetic algorithm to achieve an optimal solution. VBA blocks, which are kinds of add-in functions in Arena, are used to connect Arena with the genetic algorithm. The system being modeled has seven workstations, one loading/unloading station, and three AGVs (Automated Guided Vehicle). Also it contains three products, which each have their own machining order and processing times. We experimented with two kinds of buffer allocation problems with a proposed heuristic algorithm, and we will suggest a simple heuristic approach based on processing times and workloads to validate our proposed algorithm. The first experiment is to find a buffer profile to achieve the maximum throughput using a finite number of buffers. The second experiment is to find the minimum number of buffers to achieve the desired throughput. End of this paper, we compare the result of a proposed algorithm with the result of a simple buffer allocation heuristic based on processing times and workloads. We show that the proposed algorithm increase the throughput by 7.2%.t by 7.2%.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10a
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• pp.241-253
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• 1998

By the rapid expansion of containerization and intermodel transportation in international shipping since the 1970's, the larger containerships have emerged and concentrated their calls at a limitted number of ports. Moreover, large-scale container terminals have been built to accommodate the ever-larger containerships, and the mordernization of terminal facilities and many developments in information technology etc. have been brought out. Thus, unlimited competition has been imposed on every terminal with neighbouring ports in Japan, Singapore, Hongkong and Taiwan etc. The purpose of this study is invested to suggest how the container terminal operators cope with unlimited competition between local or foreign terminals. The results are suggested as follows : First, transshipment cargoes, which the added value is high, is to be induced. Second, the function of storage is given on On-Dock Yard. Third. Berth Pool Operation System is introduced, especially in Gamman Container Terminal and Kwangyang Container Terminal. Fourth, the cargo handling charges is decided by terminal operator.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.4
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• pp.326-333
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• 2001

This paper focuses on a method to connect mobile devices such as mobile robot. Automated Guided Vehicle (AGV) and Unmanned Container Transporter(UCT) to a fieldbus. In this paper, the IEEE 802.11 wireless LAN is used to extend a Profibus network for the mobile devices. In order to integrate these two networks, a gateway is developed using two threads and an internal buffer. Furthermore, a polling algorithm is applied at the gateway in order to satisfy real-time requirements on data communication, Finally, the performance measures such as data latency and throughput are experimentally evaluated on a wirelessly-extended Profibus network. The results shows the feasibility of the wireless extension of Profilbus for various mobile device.

• Journal of the Korea Society of Computer and Information
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• v.8 no.2
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• pp.1-7
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• 2003

This study is a research on character recognition based on image processing, using only color tape to mark guidelines instead of magnetic tape or electric wire used by existing AGV. AGV must follow given courses, and stop recognizing signs such as marks and numbers that indicate destinations. In this study. marks to stop AGV employed blue characters of the same font and size as those of number plates. Yellow driving lines and blue numeric characters were marked in corridors. AGV ran ing the characteristics of colors and detecting lines, and temporarily stopped recognizing numbers of 100％ through DP pattern matching. This study presented the image processing technique and the result of operating AGV.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.05a
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• pp.103-112
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• 2005

자동화 컨테이너 터미널의 생산성을 향상시키기 위해서는 장치장과 안벽 사이를 오가며 컨테이너를 운반하는 무인유도 차량(Automated Guided Vehicle: AGV)들이 효율적으로 주행하여 제 시간에 필요한 위치에 도착함으로써 연계 작업들의 지연을 최소화하여야 한다, 만일 AGV들이 목적지까지 주행하여야 하는 거리가 길거나 주행 중에 다른 AGV들과의 충돌이나 교축을 피하기 위하여 대기하여야 하는 상황이 빈번히 발생하면 주행 효율이 떨어지게 된다, 주행 경로의 길이를 줄이기 위하여 경로들을 보다 유연하게 설정할 수 있게 허용하면 경로들간의 교차 가능성이 높아져 교통 통제가 어려워지고 결과적으로 충돌과 교착이 발생할 가능성은 높아진다. 특히 교착을 사전에 방지하기 위하서는 문제가 발생할 소지가 있는 영역을 미리 파악하여 일부 영역을 다른 AGV들이 점유하지 못하도록 제한하여야 하는데, 이는 자칫 AGV 주행 공간의 활용도를 떨어뜨릴 수 있다. 또한 교착의 파악과 이를 방지하기 위한 제어는 실시간에 이루어져야 하므로 연산 부담이 상당하다. 본 논문에서는 유연한 주행 경로 설정이 가능하며 주행 공간을 효율적으로 활용할 수 있는 주행 경로 표현법과 충돌 방지 방안을 제안한다. 또한 교착 발생 가능성을 사전에 파악하고 회피(avoidance)하는데 소요되는 연산비용을 줄여 실시간 적용 가능성을 높이기 위하여 교착해결(deadlock resolution)에 기반을 둔 AGV 주행 관리 방안을 제시한다. 본 논문에서 제안하는 방안의 효율성을 시뮬레이션을 통하여 검증해 보았다.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.545-554
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• 2005

Passive velocity field control (PVFC) was previously developed for fully mechanical systems, in which the motion task was specified by behaviors in terms of a velocity field and the closed-loop was passive with respect to the supply rate given by the environment input. However, the PVFC was only applied to a single manipulator. The proposed control law was derived geometrically and the geometric and robustness properties of the closed-loop system were also analyzed. In this paper, we propose a virtual passivity-based algorithm to apply decentralized control to multiple 3­wheeled mobile robotic systems whose subsystems are under nonholonomic constraints and convey a common rigid object in a horizontal plain. Moreover, it is shown that multiple robot systems ensure stability and the velocities of augmented systems converge to a scaled multiple of each desired velocity field for cooperative mobile robot systems. Finally, the application of proposed virtual passivity-based decentralized algorithm via system augmentation is applied to trace a circle and the simulation results is presented in order to show effectiveness for the decentralized control algorithm proposed in this research.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.6
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• pp.515-525
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• 2022

The wireless power transfer (WPT) charging system for AGV depends highly on the coupling conditions due to air gap variation. To attain stable output power with high transfer efficiency under various coupling conditions, a single-stage, DC-DC converter that operates with robustness to changes in air gaps is proposed for the WPT system. The proposed converter is capable of soft switching under the set input voltage (V_in: 380 V_DC), load conditions (0-1 kW), and air gap changes (30-70 mm). In addition, a wide output voltage range (Vo: 39-54 V_DC) can be controlled by varying the link voltage due to the phase control at a fixed switching frequency. Experimental results are verified using a prototype of a 1 kW wireless power charging system.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.112-120
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• 2021

Recently, the number of consumers using digital online distribution platforms is increasing. This caused the rapid growth of the e-commerce market and increased delivery volume in urban areas. The logistics system, designed ar006Fund the city center to handle the delivery volume, operates a delivery system from the outskirts of the city to the urban area using cargo trucks. This maintains an ecosystem of high-cost and inefficient structures that increase social costs such as road traffic congestion and environmental problems. To solve this problem, research is being conducted worldwide to establish a high-efficiency urban joint logistics system using urban railway facilities and underground space infrastructure existing in existing cities. The joint logistics system begins with linking unmanned delivery automation services that link terminal delivery such as cargo classification and stacking, infrastructure construction that performs cargo transfer function by separating from passengers such as using cargo platform. To this end, it is necessary to apply the device to the vertical and horizontal transportation machine supporting the vertical transfer in the flat space of the joint logistics terminal, which is the base technology for transporting cargo using the transfer robot to the destination designated as a freight-only urban railway vehicle. Therefore, this paper aims to derive holistic viewpoints needs for design requirements for vertical and vertical transportation machines and freight transportation standard containers, which are underground railway logistics transport devices to be constructed by urban logistics ecosystem changes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.311-316
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• 2004

LMTT (Linear Motor-based Transfer Technology) is a horizontal transfer system for the yard automation. which has been proposed to take the place qf AGV (Automated Guided Vehicle) in the maritime container terminal. the system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle mr. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research structural optimization for a mover of shuttle mr is performed to minimize the weight satisfying design criteria the objective function is set up as weight. On the contrary, design variable is considered as transverse, longitudinal and wheel beam's thickness and shape variable determining the dimension toward high direction and the constraints are the stresses.

• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.541-548
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• 2004

In the maritime container terminal. LMCTS (Linear Motor-based Container Transfer System) is horizontal transfer system for the yard automation, which In., been proposed to take the place of AGV (Automated Guided Vehicle). The system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that is consists of stator modules on the rail and shuttle car (mover). Because of large variant of mover's weight by loading and unloading containers, the difference of each characteristic of stator modules, and a stator module's trouble etc. LMCTS is considered as that the system is changed its model suddenly and variously. In this paper, we will introduce the softcomputing method of a multi-step prediction control for LMCTS using DR- FNN (Dynamically-constructed Recurrent Fuzzy Neural Network). The proposed control system is used two networks for multi step prediction Consequently, the system has an ability to adapt for external disturbance, detent force, force ripple, and sudden changes by loading and unloading the container.