• 대한산업공학회지
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• 제14권1호
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• pp.31-42
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• 1988

This paper studies class-based turnover assignment rule in terms of the expected travel time in automated storage/retrieval systems (AS/RS). With the rack face not necessarily in square in time, travel time models of two and three-class systems are developed, from which class partition values are determined for single command cycle. Also, the effects of the system parameters such as the rack shape factor and the skewness of the ABC curve are evaluated on the travel time through example problems.

• 대한산업공학회지
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• 제22권2호
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• pp.179-188
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• 1996

We study n-class-based storage policy for an automated storage/retrieval system (AS/RS) and derive the closed form expressions of expected travel times under single command cycle. In order to confirm the correctness of the derivations, we consider both discrete and continuous storage racks, and show that the expressions for expected travel times of discrete rack converge to those of continuous one. We also derive the expected travel times when the coordinate locations for storages or retrievals are triangularly distributed and we try to solve class layout problem using the obtained results. Numerical examples are given in case of 3-class-based storage policy.

• 산업기술연구
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• 제14권
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• pp.49-61
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• 1994

This study deals with the automated storage/retrieval systems (AS/RS) where the rack is discrete and the random storage assignment rule is adopted. New storage policies named FNSC (first no-cost zone, second closest-open location) and FNSH (first no-cost zone, second a half side closest-open location) are proposed. Simulation results indicate that performance of FNSH is slightly lower than that of the SCL but it does not need much time to perform. The "stay" strategy of S/R machine is examined as a means of increasing the frequency of dual command.

• 대한안전경영과학회지
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• 제3권3호
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• pp.97-106
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• 2001

This paper considers automated storage and retrieval systems with double shuttle. We developed the expected travel time model based on the first come first served rule. An heuristic procedure by retrieval order sequencing was presented which aimed to improve the operation efficiency laking advantage of ＂No cost zone＂. Through sensitivity study, we evaluated the performance of the double shuttle system working on the four command cycle.

• 산업경영시스템학회지
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• 제20권41호
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• pp.95-102
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• 1997

This paper deals with an order picking system in an automated storage and retrieval system(AS/RS). For the order picking system, two fundamental policies, the batching and the picking policies, must be selected. The batching policy determines the manner in which orders are combined for picking in each trip of picking machine. The picking policy determines the sequence of all items in each group of orders. Most of studies for the batching policy doesn't consider dynamic arrivals and due dates of orders. Therefore, we present an batching policy which considers dynamic arrivals and due dates of orders. The presented batching policy is efficient for the automated storage and retrieval system which is connected with a manufacturing system.

• 산업경영시스템학회지
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• 제16권28호
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• pp.39-47
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• 1993

In this paper, We develop performance evaluation model for Twin fork Automated Storage/Retrieval systems. The system is modeled as a modified bulk service queueing system consisting of one exponential server with limited system capacity. The differance between this model and general bulk service queueing model is the inequality of transition service rate of each stage. The ejective of this model is to provide system characteristics for Twin fork AS/R system design problems, which are the number of customers in system, wait time in system and queue, the system queue size.

• 산업공학
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• 제18권4호
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• pp.431-443
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• 2005

This paper describes a web-based system called DESIGNER for the analysis and design for automated material handling equipment(MHE) applications in manufacturing. DESIGNER models the processes for system integration, economic analysis, performance analysis, and automated storage/retrieval system(AS/RS) design. Based on the information specified by users, the various analysis modules are invoked to meet the needs of the material handling applications. The results of the analyses provide system users with useful data for material handling system design and decision on investment in automated MHE. Example problems are also presented to demonstrate the use of the system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.198-201
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• 1999

An automated storage and retrieval machinery for high rack warehouse systems is developed in order to stack the various kinds of productions. However, according to increase in the rack height, the long lead time should be taken. In stacker crane systems, the variations of the lifting height and the load generate the vibration of lifting machine, and it makes a Position control to be difficult Therefore, the reduction of vibration will be important factor for saving the lead time and the damage of Productions. This paper deals with a position control of stacker crane in automated high rack warehouse system by using a gain-scheduled control algorithm via a LMI method, where the variations of elastic coefficient of the stacker crane's post are considered.

• 산업경영시스템학회지
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• 제34권3호
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• pp.1-7
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• 2011

The stocker system is another name of automated storage and retrieval system (AS/RS) and being popularly used as main material handling tools in Liquid Crystal Display (LCD) and semiconductor fabrication facilities. Recently the use of the stocker system has been extended to transportation from conventional storage and retrieval in LCD fabrication facilities. Toolsets are connected in the ground level of the stocker system and 4~6 stories of the shelves are placed in the upper or lower ground level. As a consequence of the more sophisticated design, move requests imposed on the system greatly increased. For solving this problem, the industry adopted the dual-robot stocker system that two robots are moving along the same guide line in the stocker system. This research develops a closed-form solution to estimate a delivery rate of the dual robot stocker system under given design and operation parameters. Using this stochastic model, industry practitioners could analyze performance levels under given various design parameters, and ultimately the model helps optimizing the design parameters.

• 한국산업정보학회논문지
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• 제4권2호
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• pp.62-72
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• 1999

본 논문에서는 자동창고시스템과 자재취급시스템이 통합된 통합자동생산시스템의 하나인 DIO가공시스템을 고려한다. DIO가공시스템에서는 스태커크레인이 가공물의 저장을 위한 운반은 물론 각 기계 사이의 가공물 운반역할을 담당하게 된다. 이러한 시스템에서 일어날 수 있는 문제로 크게 시스템 설계와 관련된 문제와 시스템운영과 관련된 문제로 구분하고 본 논문에서는 시스템의 운영정책에 관련된 문제만을 다룬다. 시스템의 운영과 관련된 문제로는 가공물투입순서, 가공물의 저장위치, 스태커크레인의 작업배정, 가공물선택 등으로 크게 4가지로 나누어서 고려한다. 각각의 운영정책에 대해서 기존의 연구결과로부터 DIO가공시스템의 특성을 반영하는 몇 가지씩의 운영정책을 대안으로 제시하고 최적의 운영정책 결정을 위한 방법론으로 컴퓨터시뮬레이션과 유전자알고리즘을 통합한 방법론을 제시한다. 또한 실험을 통해서 기존의 연구결과와 비교 검토함으로서 제시된 알고리즘의 우수성을 검증한다.