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Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this paper is to validate travel time models for single cycle displacements of S/R machine in multi aisle automated storage and retrieval system (AS/RS) by using experimental computer simulation. The models under consideration take into account class based storage. We use ARENA 12 software for the simulation modeling. By simulation, we emulate the real functioning of the system. Therefore, we assume that the results from the ARENA simulation are equivalent to the onsite experimentation. Simulation results present a comparative study carried between a class-based storage and purely random storage. [ABSTRACT FROM AUTHOR]

In this paper, the aim is to determine the optimal dimensions of a flow rack automated storage and retrieval system (AS/RS) using a single machine for storage and retrieval operations. These optimal dimensions are evaluated for minimum expected travel times of the storage and retrieval machine. An enumeration technique is used on a large range of system configurations going from 100 to 20,000 storage segments. Initially, optimization is carried out on six travel time expressions dealing with single and dual cycle travel times considering two dwell point positions. The results are then studied to investigate the influence of travel time expressions on both optimal dimensions and the shape factor of the system rack. Secondly, a new generalized mathematical model was developed by introducing an occurrence proportion parameter, relative to dual cycles, in order to determine the influence of the system functioning (proportion of dual cycles and load rate) on optimal dimensions. [ABSTRACT FROM AUTHOR]

• AS/RSs are industrial equipment used to automate activities related to warehousing. • The AS/RS dimensions optimization for minimum cycle time problem is addressed. • The faced time/precision dilemma (during AS/RSs design optimization) is highlighted. • Mathematical properties are identified by studying cycle time models. • A fast exact resolution method is set up using the demonstrated dominance properties. • The loss in precision of the commonly used fast approximate methods is shown. Optimizing the design of storage systems is of crucial importance for operational excellence. The aim of this paper is to explore the optimization of the design for automated storage systems. In this latter, we are interested in three different systems. First, we highlight the different methods used to deal with this problem and point out their limits. Thereafter, we present the different corresponding cycle times models. Then, we identify and demonstrate several mathematical properties, which we use as dominance properties to implement an efficient resolution algorithm. Our algorithm greatly surpasses the existing optimization methods used for the design optimization problems. The proposed approach allows us to obtain the optimal solution ten times faster than the commonly used methods, as illustrated by a comparative numerical study. [ABSTRACT FROM AUTHOR]