Traffic Management of Multi-AGV Systems by Improved Dynamic Resource Reservation

Abstract

Automated guided vehicles (AGVs) are widely used for material handling in warehouses and automated production lines due to their high efficiency and low failure rate with respect to human operated load carriers. However, AGVs usually interact with each other because of the restricted capacity of the layout, and conflicts arise. Although many traffic scheduling algorithms have been proposed to address the AGV fleet control problem, most of them are inefficient for collision and deadlock avoidance in dynamic environments. This paper proposes an improved dynamic resource reservation (IDRR) based method which renders time-efficient task completion and deadlock-free movements of multiple AGVs in a manufacturing system. Unlike traditional approaches, most of which adopt a dynamic single agent reservation of the shared resource points and/or force path deviations, IDRR exploits dynamic multiple reservations of shared resource points. This is combined with a conflict detection and resolution method that accommodates the AGV motions when they meet at a resource point. Extensive, realistic simulation results demonstrate the feasibility and efficiency of the proposed collision and deadlock prevention method in productivity, travelled distance, and time completion of the assigned tasks. The proposal can be implemented on both central and local controllers.

Keywords

• Multi-AGV systems
• collision and deadlock avoidance
• dynamic resource reservation
• traffic control