A semi-dynamic time window constrained routeing strategy in an automated guided vehicle system

This study addresses the issue of vehicle route planning in an AGV system. The two salient approaches to route planning—static and dynamic—are briefly discussed. The main thrust of the present work is development and testing of a proposed semi-dynamic time window constrained routeing strategy. Reserved time windows are placed on nodes indicating sequential crossing of nodes by the respective vehicles. Free time windows represent empty time slots available for vehicles to cross the nodes. Similarly, time windows representing the direction of traffic flow are placed on the bidirectional arcs. Based on these time windows, Dijkstra's algorithm is applied to find the least congested fastest routes for vehicles. A simulation study of a bidirectional flow path is then reported. The aim of the simulation experiment is to evaluate the system performance under the proposed routeing strategy vis-à-vis static routeing strategy. The results show that the proposed routeing strategy helps in reducing vehicle blocking time and improving the throughput potential of the system.