New control policies preventing deadlock in automated manufacturing systems

In this paper we propose a hybrid approach to prevent deadlock between parts flowing in manufacturing systems. The approach uses both Petri nets and digraphs to exploit the higher simplicity of digraphs to detect deadlock combined with theoretic results known for Petri nets. The new PN-based prevention policies translate the information obtained from properly defined digraphs into empty siphons of a corresponding PN modeling the same system.