Iterative Deadlock Control Policies In Petri Nets

Iterative deadlock control is a kind of methods to address deadlock prevention ofPetri nets. Control places are added for uncontrolled siphons until the controlled net hasno emptiable siphon or dead state. In the Iterative processes, control places usuallyresult the controlled net being a generalized Petri net. In fat, adding control place canonly prevent a siphon becoming empty in a PT-ordinary net. Thus, it is particularlyimportant to develop a deadlock control policy for a generalized Petri net.This thesis focuses on deadlock prevention in Petri nets. Firstly, four availablepolicies of siphon-based iterative deadlock control are analyzed and examined. Thesealgorithms, based on covering set of uncontrolled minimal siphons, combine markingswith minimal siphons. This makes the controlled Petri net can be usually controlledoptimally. Next, based on MESP-ISC, the last one of the above mentioned policies,three deadlock control policies are developed, by which a generalized Petri net can becontrolled. In the developed deadlock control policies, many problems are involved,transformation from a generalized Petri net to an ordinary one, back-transformationfrom a controlled Petri net to the original Petri net, covering set of uncontrolled minimalsiphons, deadlock generation problem, removing redundant control places, etc. Integerlinear programming is widely used for the solution of the above problems.