In: 1: International Journal of Production Research, Vol. 42, No. 9, pages 1787-1814. May 2004.
Abstract: Automated Guided Vehicle Systems (AGVSs) are material handling devices representing an efficient and flexible option for products management in Automated Manufacturing Systems. In AGVSs vehicles follow a guide-path while controlled by a computer that assigns route, tasks, velocity, etc. Moreover, the design of AGVSs has to take into account some management problems such as collisions and deadlocks. This paper presents a novel control strategy to avoid deadlock and collisions in zone controlled AGVSs. In particular, the control scheme manages the assignments of new paths to vehicles and their acquisition of the next zone. Moreover, we propose the use of Coloured Petri Nets (CPNs) to model the dynamics of AGVSs and implement the control strategy stemming from the knowledge of the system state. Additionally, extending the CPN model with a time concept allows investigation of the system performance. Several simulations of an AGVS with varying fleet size while measuri! ng appropriate performance indices show the effectiveness of the proposed control strategy compared to an alternative policy previously presented by one of the authors.
Keywords: Automated guided vehicle systems; Coloured Petri nets; modeling; deadlock; control.
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