• Journal of the military operations research society of Korea
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• v.17 no.2
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• pp.90-99
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• 1991

In this paper a dispatching rule, $D^{*}$, for AGV operations in automated manufacturing system is proposed to improve the performance measures. And the algorithm is compared with existing heuristic rules via simulation to evaluate its capabilities. It is shown that the proposed rule enhances mean flow time, makespan and throughput, and avoids the locking phenominon which can be fatal to the operation of automated manufacturing systems.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.67-81
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• 1998

An Automated Guided Vehicle System (AGVS) with a unidirectional loop guide path is modeled as a discrete-time stationary Markov chain. It is discussed how to estimate the mean response time, the utilization, and the cycle time of AGV for a delivery order. Three common operation strategies for idle vehicles - central zone positioning rule, circulatory loop positioning rule and point of release positioning rule - are analyzed. These different operation strategies are compared with each other based on the performance measures.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.509-512
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• 2000

AGV 는 자동화된 생산 시스템에 없어서는 안 되는 중요한 요소로 자리잡았다. 하지만 생산 시스템의 규모가 커짐에 따라 설계와 운영에 있어 많은 어려움이 생겼고, 이를 극복하기 위해서 새로운 형태의 AGV시스템이 제시되고 있다. 이중 대표적인 것이 Tandem AGV 시스템이다. Tandem AGV 시스템은 전체 시스템을 몇 개의 지역으로 분할하고, 하나의 지역에 한대의 차량을 할당하는 방식으로 운영의 효율성을 꾀하고 있다. 본 연구에서는 Multi-load AGV 를 사용하는 Tandem AGV 시스템을 설계하기 위한 효율적인 방법론을 제시하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.180.4-180
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• 2001

This paper describes a vision-based line-tracking system for AGV and steering control scheme. For detect the guideline quickly and exactly, We use four line-points which complement and predict each other. This low-cost line-tracking system is efficiently using PC-based real-time vision processing, Steering control is studied through an steering controller with guide-line angle and line-point error. This method is tested via a typical AGV with a single camera in laboratory environment.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.36-42
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• 2001

This paper presents the operational planning systems of automated container terminals. The proposed system is composed of berth allocation module, yard planning module, resource allocation module, sequencing module, and simulation module. All the sub-modules except resource allocation module are built into integrated simulation model using simulation package AutoMod. Simulation experiments are performed according to the number of AGVs and AGV allocation policies.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.855-860
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• 2006

In the environment where multiple 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 one of the factors 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 set of time-driven simulation works validated the effectiveness of the proposed methods.

• Structural Engineering and Mechanics
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• v.45 no.4
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• pp.543-568
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• 2013

This study explores the floor micro-vibrations induced by the automated guided vehicles (AGVs) in liquid-crystal-display (LCD) factories. The relationships between moving loads and both the vehicle weights and speeds were constructed by a modified Kanai-Tajimi (MKT) power spectral density (PSD) function whose best-fitting parameters were obtained through a regression analysis by using experimental acceleration responses of a small-scale three-span continuous beam model obtained in the laboratory. The AGV induced floor micro-vibrations under various AGV weights and speeds were then assessed by the proposed regressional MKT model. Simulation results indicate that the maximum floor micro-vibrations of the target LCD factory fall within the VC-B and VC-C levels when AGV moves at a lower speed of 1.0 m/s, while they may exceed the acceptable VC-B level when AGV moves at a higher speed of 1.5 m/s. The simulated floor micro-vibration levels are comparable to those of typical LCD factories induced by AGVs moving normally at a speed between 1.0 m/s and 2.0 m/s. Therefore, the numerical algorithm that integrates a simplified sub-structural multi-span continuous beam model and a proposed regressional MKT moving force model can provide a satisfactory prediction of AGV-induced floor micro-vibrations in LCD factories, if proper parameters of the MKT moving force model are adopted.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.41-46
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• 2020

The start of the Fourth Industrial Revolution has brought about various changes in the domestic industry in general, and smart factories have spread to companies in the fields of production, manufacturing and logistics, and they are using automation equipment. Especially in the field of logistics automation, AGVs are widely used, and most of them use the line guidance system, which is the traditional AGV drive system. In addition, the demand for AGV system developers, system operators and managers, and maintenance personnel is increasing, and the installation of systems for education is expensive and requires a large space to utilize. It is a situation where systematic education is difficult. In this paper, we propose a virtual simulation-based AGV distance education model for smooth practice of trainees. The proposed model consisted of a model that can drive the AGV by analyzing video information, instead of the line guidance method that is the conventional technology. As a result of self-diagnosis evaluation, it was confirmed that the experimental group through online education had an average satisfaction level of 0.65 higher than the control group using existing equipment, and that it could be used in an online education environment.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.133-142
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• 2008

AGV systems are widely used to increase the flexibility and the efficiency of the material handling systems. AGV systems are one of critical factors which determine the overall performance of the manufacturing systems. To this end, the optimal design for AGV systems is essential. Commercial simulation software is often used as an analysis tool during the design of AGV systems, however a series of procedures are desirable to simplify the analysis processes. In this paper, we present and develop the architecture for unidirectional AGV systems simulator which is able to consider approximate optimal unidirectional flow path and various operational parameters. The designed AGV systems simulator is based on JAVA, and it is developed to support designing approximate optimal unidirectional network by using Tabu search method. In addition, it enables users to design and evaluate AGV systems and to analyze alternative solutions easily. Simulation engine is consists of layout designer, AGV operation plan designer, and integrated AGVS layout designer. Users enter their system design/operation information into input window, then the entered information is automatically utilized for modeling and simulating AGV systems in simulation engine. By this series of procedures, users can get the feed back quickly.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.837-844
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• 2008

In an automated container terminal, various factors affect the operation of container handling equipment such as quay cranes and AGVs, and thus calculating the exact operation time is nearly infeasible. This uncertainty makes it difficult to dispatch AGVs well. In this paper, we propose a simulation-based AGV dispatching algorithm When dispatching an AGV to an operation, the proposed algorithm conducts multiple stochastic simulation for the succeeding AGV operations for the predetermined period to collect stochastic samples of the result of the dispatching. In the stochastic simulation, the uncertainty of crane operations is represented as a simple probability distribution and the operation time of a crane is determined according to this. A dispatching option is evaluated by the total delay time of quay cranes which is estimated by averaging the quay crane delay of each simulation In order to collect a sufficient number of samples that guarantee the credibility of the evaluation, we devised a high-speed simulator that simulates AGV operation The effectiveness of the proposed algorithm is validated by simulation experiments.