An approach for computing AS/R systems travel times in a class-based storage configuration

Abstract

This study provides an approach to compute the travel time for AS/R systems in a class-based storage environment. A regression analysis is completed in order to define the importance of the key predictors taken into account and to propose a formulation of travel times. The results show the reliability of the model and allow to evaluate the travel time through the identification of a complete list of predictors. The proposed approach supports managers in theex-ante definition of travel times for a warehouse. A correct evaluation of travel times enables a better monitoring of the performance of warehouse operations and can support practitioners in the choice of the configuration not only in terms of kind of cycle, but also from a policy assignment perspective. From a theoretical point of view, this work can be considered as an attempt to refine the existing methods to compute travel times.

AS/R system travel time in class-based storage with different input-output point levels: a proposed formula

“…The present work advances the studies by Schenone et al (2019Schenone et al ( , 2020 by proposing a simulation model, combined with an empirical regression analysis, to calculate the S/R machine travel time. To be more precise, the aim is extending the results obtained by Bozer and White (1984) related to SC and DC cycles under a class-based storage policy.…”

“…The joint application of the class-based storage policy and an appropriate rack design results in a more efficient utilization of warehouse areas characterized by relevant heights. Later on, Schenone et al (2020) enlarge the application fields of the Bozer and White's (1984) formula to class-based storage by developing numerical equations to compute the travel time by taking into account the warehouse shape factor and the turnover of the stored products. Recently, Mirzaei et al (2021) perform a research on the impacts on AS/RS travel time estimation of combining the class-based storage policy with the part-to-picker approach.…”

“…In the present research, simulations are carried out by means of a Microsoft Excel V R macro to calculate the travel time under the assumptions detailed in the third section as well as heterogeneous warehouse conditions. The simulation approach is corroborated based on literature, in particular the contributions by Schenone et al (2019Schenone et al ( , 2020 considering both the Bozer and White's (1984) and the analytical approach. The validation is carried out for the main possible operational warehouse situations, in particular when the I/O point is located on the floor since there are few available works relying on variable I/O point height.…”

Multi-shuttle AS/RS dimensions optimization using a genetic algorithm—case of the multi-aisle configuration

“…Unlike the model proposed by [13], this model is completely continuous. Moreover, [22]suggested a linear regression-based approach for the calculation of the cycle time using class-based storage for a unit-load automated storage/ retrieval system (AS/RS).…”

An exact optimization method based on dominance properties for the design of AS/RSs

“…Dealing with the mobile-rack AS/RS, Guezzen, et al (2013) developed continuous cycle time models and evaluated their accuracy via simulation. By taking an interest in the classical unit-load AS/RS (which is in fact an aisle-captive multi-aisle), Schenone, et al (2018) proposed cycle time models when using dual-shuttle handling machines whereas Schenone, et al (2020) proposed for this same system an approach to compute the travel time in a class-based storage environment. They completed a regression analysis in order to define the importance of the key predictors taken into account.…”