• Journal of Navigation and Port Research
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• v.28 no.7
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• pp.635-640
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• 2004

In this paper, a tracking algorithm for autonomous navigation of automated guided vehicles (AGVs) operating in container terminals is presented. The developed navigation algorithm takes the form of a federated information filter used to detect other AGVs and avoid obstacles using fused information from multiple sensors. Being equivalent to the Kalman filter (KF) algebraically, the information filter is extended to N-sensor distributed dynamic systems. In multi-sensor environments, the information-based filter is easier to decentralize, initialize, and fuse than a KF-based filter. It is proved that the information state and the information matrix of the suggested filter, which are weighted in terms of an information sharing factor, are equal to those of a centralized information filter under the regular conditions. Numerical examples using Monte Carlo simulation are provided to compare the centralized information filter and the proposed one.

• Journal of Korea Multimedia Society
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• v.19 no.3
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• pp.539-547
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• 2016

Automated guided vehicles (AGVs) are widely used in industry. Several types of vision-based AGVs have been studied in order to reduce cost of infrastructure building at floor of workspace and to increase flexibility of changing the navigation path layout. A practical vision-based guideline tracing method is proposed in this paper. A virtual tracing wheel is introduced and adopted in this method, which enables a vision-based AGV to trace a guideline in diverse ways. This method is also useful for preventing damage of the guideline by enforcing the real steering wheel of the AGV not to move on the guideline. Usefulness of the virtual tracing wheel is analyzed through computer simulations. Several navigation tests with a commercial AGV were also performed on a usual guideline layout and we confirmed that the virtual tracing wheel based tracing method could work practically well.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.1
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• pp.121-139
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• 1992

AGVS(Automated Guided Vehicle Systems) in material handling have been used widely since late 1970s. Implementation of an AGVS generally requires substantial study to optimize the design and performance of guide-paths. Traditional mathematical approaches have been used with limited success to analyze AGVS. These approaches, however, do not provide a practical tool for guide-path designers. This paper presents a new approach based on rules in designing and assessing AGV guide-paths to improve the design of a closed-loop layout. A framework for the integrated approach is proposed, problem solving procedures are explained, and a case study is reported to demonstrate the framework. Deletion of seldom used guide-paths, and addition of bypasses to solve the congestion problem, are conducted interactively and iteratively through simulation experiments. To visualize the results, a graphic control program is developed and integrated with the AutoMod/AutoGram simulation package.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1743-1746
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• 2003

Automated Container Terminals have been being developed over the world for many recent years and more and more countries get interested in it because the amount of containers exported or imported is steeply increasing. Existed Container Terminals were not designed to control this kind of heavily many containers. They would face many structural problems soon or later, although they have managed to do well until now. One of the most important things in developing Automated Container Terminal is to develop the equipment able to transfer the awfully many containers. Those are maybe Automated Transfer Cranes, Automated Guided Vehicles, and Automated Quay-Side Cranes. The word "Automated" means the equipment is operated without drivers and those equipments are able to work without taking any break. Through the researches on the existed transfer cranes, authors decided that the structure of existed transfer cranes is not proper to swift and fast transfer and it′s not impossible to handle so many containers in limited time. Therefore authors have been studying on the proper structure of the Automated Container Crane for past several years and a new type of transfer crane has been developed. Design concepts and control methods of a new crane will be introduced in this paper.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.195-197
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• 2009

It is a proven fact with the opening of the Seoul metro line number 1 in 1974 traffic congestion on the roads has decreased and the efficiency of people transportation in general has greatly been enhanced in the downtown and surrounding areas of Seoul. Even today construction of new subway lines are under way and many more are being planned due to the easy access to stations, short waiting and average travel times, compared with personal vehicles, contributing to the efficiency of the public transportation systems that are linking the downtown areas and also the intercity systems in moving passengers during rush hour and times of special event. Since the labour costs of the train operator in any large city based subway system accounts for a major part of the operating costs per kilometer and to ensure cost efficient operations, especially during non-peak hours, it is necessary to implement an unmanned(auto-driven) subway system. In order to implement such a system it is imperative that the on-board and wayside signalling control systems be fully automated as well. Only through proper examination of safety procedures not only by the AUGT(Automated Urban Guided Transport)system but also by ail the international standards organizations involved can safely and stability be ensured.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1112-1118
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• 2004

Automated container terminals have been developed over the world years and many countries are interested in them because the amount of containers exported or imported is rapidly increasing. The conventional container terminals were not designed to handle this kind of heavily many containers. They would face many structural problems soon or later, although they have been managed to do well so far. One of the most important things in automated container terminal is the handing equipments able to transfer many containers efficiently. Those are maybe automated transfer cranes, automatic guided vehicles and automated quay-side cranes. The word 'automated' means the equipment is operated without drivers and those equipments are able to work without any interruption in working schedule. Through the researches on the conventional transfer cranes, we decided that the structure of conventional transfer cranes is not proper in automated container terminal and it is not possible to handle so many container in limited time. Therefore we have been studying on the proper structure of the automated container for past several years and a new type of transfer cranes has been developed. Design concept and control method of the new crane are introduced and experimental results are presented in this paper.his paper.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.23
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• pp.47-55
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• 1991

In automated assembly line, an automatic guided vehicle system(AGVS) represents a mire versatile means of moving materials automatically. In this paper, the vehicles not only provide the transportation medium between workstations but also as mobile workstations. The objective for the developed model is the determination of the appropriate time to control AGV based assembly line in order to minimize production makespan while maximizing the efficient use of vehicles. In this paper, we consider the finished goods of two types which are produced in assembly line. The assembly line is considered with and without queue. Because no buffer are present in case 1. this model seeks to determine the point in time at which vehicles should be launched in the assembly line without experiencing a delay. The case 2 model also seek to determine the vehicle launch times while minimizing production makespan. The assumption in this model is that the maximum queue size cannot exceed 1 at any time.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.111-118
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• 2000

This paper proposes the track layout criterion for the LRT(light rail transit). All criterions established concerning dimension and performance of LRT vehicles that are three types. Types of vehices are AGT(automated guided train) steel wheel. AGT rubber tire and LIM(linear induction motor). Using theoritical approach, adaptation and validity of criterions are verified. Proposed criterions may provide a standard scheme for design and construction of the infrastructure on LRT.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.387-392
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• 2006

In the environment where AGVs(Automated Guided Vehicles) operate concurrently in limited space, collisions. deadlocks, and livelocks which have negative effect on the productivity of AGVs occure more frequently. The accelerated motion of an AGV is also the factor that make the AGV routing more difficult because the accelerated motion makes it difficult to estimate the vehicle's exact travel time. In this study, we propose methods of avoiding collisions, deadlocks, and livelocks using OAR(Occupancy Area Reservation) table, and selecting best route by estimating the travel time of an AGV in accelerated motion. A time-driven simulation validated the effectiveness of the proposed methods.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.5
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• pp.591-595
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• 2010

In this paper, a method that dynamically adapts the traffic flow of automated guided vehicles (AGVs) used in automated container terminals to the changing operational condition is presented. In a container terminal, the AGVs are vulnerable to traffic congestion because a large number of AGVs operate in a limited area. In addition, dynamically changing operational condition requires the traffic flow of AGVs to be continuously adjusted to keep up with the change. The proposed method utilizes a genetic algorithm to optimize the traffic flow. Exploiting the dynamic nature of the problem an approach that reuses the results of the previous search is tried to speed up the convergence of the genetic algorithm. The results of simulation experiments show the efficiency of the proposed method.