Cycle-deadlock control of RGVs in autonomous vehicle storage and retrieval systems
Jian Lan Luo · Computer Integrated Manufacturing Systems · 2008
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.