• Industrial Engineering and Management Systems
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• 제6권2호
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• pp.125-135
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• 2007

An automated guided vehicle (AGV) system is a group of collaborating unmanned vehicles which is commonly used for transporting materials within manufacturing, warehousing, or distribution systems. The performance of an AGV system depends on the dispatching rules used to assign vehicles to pickup requests, the vehicle routing protocols, and the home location of idle vehicles, which are called dwell points. In manufacturing and distribution environments which emphasize just-in-time principles, performance measures for material handling are based on response times for pickup requests and equipment utilization. In an AGV system, the response time for a pickup request is the time that it takes for the vehicle to travel from its dwell point to the pickup station. In this article, an exact dynamic programming algorithm for selecting dwell points in a tandem-loop multiple-vehicle AGV system is presented. The objective of the model is to minimize the maximum response time for all pickup requests in a given shift. The recursive algorithm considers time restrictions on the availability of vehicles during the shift.

• 산업경영시스템학회지
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• 제28권1호
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• pp.55-63
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• 2005

This paper is to analyze the travel distance and the transport size of the vehicle when the AGV carries multiple-load in the tandem automated guided vehicle systems. The size of multiple-load represents the number of load that the AGV can carry simultaneously. The AGV can carry simultaneously multiple-load that load types are different. The transport system of the manufacturing system is a tandem configuration automated guided vehicle system, which is based on the partitioning of all the stations into several non-overlapping single closed loops. Each loop divided has only one vehicle traveling unidirectionally around it. The AGV of each loop has to have sufficient transport capacity that can carry all loads for given unit time. In this paper, the average loaded travel distance and the size of feasible multiple-load of the vehicle are analyzed. A numerical example is shown.

• 산업경영시스템학회지
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• 제44권4호
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• pp.145-153
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• 2021

Automated Guided Vehicle (AGV) is commonly used in manufacturing plant, warehouse, distribution center, and terminal. AGV is self-driven vehicle used to transport material between workstations in the shop floor without the help of an operator, and AGV includes a material transfer system located on the top and driving system at the bottom to move the vehicle as desired. For navigation, AGV mostly uses lane paths, signal paths or signal beacons. Various predominant sensors are also used in the AGV. However, in the conventional AGV, there is a problem of not turning or damaging nearby objects or AGV in a narrow space. In this paper, a new driving system is proposed to move the vehicle in a narrow space. In the proposed driving system, two sets of the combined steering-drive unit are adopted to solve the above problem. A prototype of AGV with the new driving system is developed for the comparative analysis with the conventional AGV. In addition, the experimental result shows the improved performance of the new driving system in the maximum speed, braking distance and positioning precision tests.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.306-306
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• 2000

This paper analyze the dynamic characteristics of Automated Guided Vehicle(AGV) which is being developed as a part of automation in port through DADS, one of the multi-dynamic analysis program, Previous evaluation of a vehicle is carried out through the continuous driving test of a real vehicle, however this method raise the loss of finance and time. If it is possible to analyze the dynamic characteristics of vehicle before construction completely we can compensate the loss of money and time during constructing. AGV contained containers is very heavy and its center of gravity can be easily changed with the disturbance from road or cornering. It makes AGV unsatisfied, therefore we evaluate the handling characteristics and stability of the full vehicle model. This paper contribute to establish the foundation of the development of a new system like a AGV which have a special structure.

• 한국경영과학회지
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• 제23권2호
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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.

• 한국시뮬레이션학회논문지
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• 제6권1호
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• pp.41-52
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• 1997

It is essential to construct an efficient material flow system for the successful introduction of automated manufacturing systems. Automated Guided Vehicle System (AGVS) plays a significant role more and more in modern manufacturing environments, because of the flexibility and the precision they offer. However, as the size and the complexity of systems increase, the problems of dispatching, routing and scheduling of AGVs become complicated due to their independent and asynchronous demands. In this paper, we review relevant papers, and provide a new and more efficient method for dispatching AGV, named MEVTT (Minimum Empty Vehicle Travel Time) and demonstrate its performance and efficiency using simulation.

• 산업경영시스템학회지
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• 제45권3호
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• pp.40-48
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• 2022

An automated material handling system (AMHS) has been emerging as an important factor in the semiconductor wafer manufacturing industry. In general, an automated guided vehicle (AGV) in the Fab's AMHS travels hundreds of miles on guided paths to transport a lot through hundreds of operations. The AMHS aims to transfer wafers while ensuring a short delivery time and high operational reliability. Many linear and analytic approaches have evaluated and improved the performance of the AMHS under a deterministic environment. However, the analytic approaches cannot consider a non-linear, non-convex, and black-box performance measurement of the AMHS owing to the AMHS's complexity and uncertainty. Unexpected vehicle congestion increases the delivery time and deteriorates the Fab's production efficiency. In this study, we propose a Q-Learning based dynamic routing algorithm considering vehicle congestion to reduce the delivery time. The proposed algorithm captures time-variant vehicle traffic and decreases vehicle congestion. Through simulation experiments, we confirm that the proposed algorithm finds an efficient path for the vehicles compared to benchmark algorithms with a reduced mean and decreased standard deviation of the delivery time in the Fab's AMHS.

• 한국지능시스템학회논문지
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• 제17권5호
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• pp.654-659
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• 2007

본 논문에서는 AGVS(Automated Guided Vehicle System)가 여러 복잡한 작업 환경 또는 작업 환경 변경 시 좀 더 유연하게 운용될 수 있도록 작업환경 내에서 AGVS에 필요한 작업공간요소를 분류하고 이들을 모델링하는 방법을 제안한다. 또한, 그래프 탐색 방법인 A* 알고리즘을 이용하여 AGV의 최단 경로 탐색 알고리즘을 본 논문의 작업환경 요소로서 재 표현한다. 생성된 최단 경로와 본 논문에서 가정한 AGV의 속도 테이블을 이용하여 운행 중인 AGV의 경로 점유 시간 알고리즘을 제안한다. 마지막으로 간단한 시뮬레이션을 통하여 제안한 방법의 적용 가능성을 증명한다.

• 한국산학기술학회논문지
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• 제12권12호
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• pp.5622-5632
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• 2011

이 논문은 Automated Guided Vehicle(AGV)를 이용하여 운영되는 통합물류시스템의 시뮬레이션 실험설계와 분석에 관한 방법을 제시한다. 물류창고의 AGVs(Automated Guided Vehicle system) 성능을 최대로 운영하기 위해선 많은 변수들이 고려되어져야 하는데 대표적 중요 요인에는 차량 대수, 속도, 운행규칙, 부품 타입, 스케줄링, 버퍼 사이즈 등이 있다. 우리는 이 논문에서 다양한 중요요인들 중 (1)처리량 최대화, (2)차량 이용률 최대화 (3)차량 혼잡 최소화, (4)Automated Storage and Retrieval System(ASRS) 이용률 최대화를 고려하기 위해 직교배열(Orthogonal Array)로 실험계획을 수립하였고 이를 이용한 시뮬레이션 기반 분석과 진화전략(Evolution Strategy : ES)를 이용한 최적화를 각각 수행했다. 그 결과 ES에 비해 직교배열이 실험 시간과 회수를 절약하였고 두 결과에 대한 유효성 검사 또한 큰 차이를 나타내지 않았다. 따라서 본 논문에서 제시한 방법을 이용한 분석 방법은 시간, 회수 그리고 실험의 정확성에 대한 분석의 효율성을 증대시킬 것으로 예상되며 통합 물류 시스템 이외의 시스템에도 적용이 가능 할 것으로 생각된다.

• 산업경영시스템학회지
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• 제22권52호
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• pp.117-139
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• 1999

This paper is concerned about the hybrid tandem configuration as the design of the automated guided vehicle system(AGVs). The hybrid tandem configuration is that the manufacturing system is divided into several non-overlapping zones, workstations of each zone are linked by network configuration including loop. That is, the manufacturing system is divided into several non-overlapping small size networks, and at most two automated guided vehicles can be available in each network. The transit point is located at proper point between adjacent networks. The parts are transported to workstations in other network through the transit points. One of the objective functions in dividing into the hybrid tandem configuration is to minimize the maximum travel time of the divided networks, and other is to minimize the total travel distance of parts moved to workstations in other networks for the next processing. The model formulation is presented, and a numerical example is shown. Also, the performances of system for the hybrid tandem, tandem and network configuration are compared through the simulation. The results of this research will contribute to the development of material handling systems in the manufacturing system. Also, it will be applied in determining the transportation area of transportation vehicles and the number and size of the transportation fleet in the transportation problem of logistics management.