Authors: Ardavan Asef-Vaziri, Gilbert Laporte
Addresses: Systems and Operations Management, College of Business and Economics, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330-8245, USA. ' GERAD and Canada Research Chair in Distribution Management, HEC Montreal, 3000, Chemin de la Cote-Sainte-Catherine, Montreal, H3T 2A7, Canada
Abstract: We compare the effectiveness and efficiency of alternative operational dispatching policies that are integrated into the design phase of a circular material handling network for automated material handling vehicles. Exact formulations describe the problem of optimal concurrent design of the unidirectional loop track layout along with the locations of the pickup and drop-off stations. The objective is to minimise the total loaded and empty vehicle trip distances, which is a surrogate for vehicle fleet size. Since first-encounter-first-served cannot be modelled on a loop and station locations which are not yet designed, we approach first-encounter-first-served optimal design through shortest-trip-distance-first. Managerial observations in support of shortest-trip-distance-first are reported. The findings of the optimisation models in the design phase are well supported by the outcomes of the simulation model in the operation phase. We conclude that one should apply shortest-trip-distance-first dispatching when designing the loop and stations and then follow first-encountered-first-served in operating the fleet of the vehicles.
Keywords: operational policies; AMH design; materials handling networks; automated guided vehicles; AGVs; dispatching policies; automated materials handling; concurrent design; simulation.
International Journal of Advanced Operations Management, 2009 Vol.1 No.1, pp.108 - 134
Published online: 18 Jun 2009 *Full-text access for editors Access for subscribers Purchase this article Comment on this article