关键词: 自动小车存取系统, 轨道导引小车系统, 有色赋时Petri网, 有向图, 环路死锁

Abstract: To avoid the cycle-deadlock of the Rail-Guided Vehicles (RGVs) systems in Autonomous Vehicle Storage and Retrieval Systems (AVS/RS), a deadlock control modeling method based on Petri nets and directed graph was proposed. The dynamic model of AVS/RS was constructed by using Colored Timed Petri Nets (CTPN). And by using directed graph tools, the cycle-deadlock was described. To deal with RGVs systems with single rail and two directions, forms of cycle-deadlock were also discussed. Moreover, the necessary and sufficient conditions for RGVs deadlock-free were presented, and the deadlockfree control policies including critical state were also proposed. Finally, a case study was given to validate the effectiveness of the proposed policy.

Key words: autonomous vehicle storage and retrieval systems, rail-guided vehicles systems, colored timed Petri nets, directed graph, cycle-deadlock