Deadlock Control in Generalized Petri Nets

This chapter proposes a number of deadlock prevention polices for a class of generalized Petri nets, namely G-systems, which is usually considered to be the most generalized Petri nets that can model Flexible Manufacturing Systems (FMSs) with machining, assembly, and disassembly operations. First, a deadlock prevention policy based on elementary siphons theory is presented, which indicates that structural complexity and behavioral permissiveness can be improved effectively. In order to reduce the computational complexity, a Mixed Integer Programming (MIP)-based deadlock detection approach is proposed, then two deadlock control polices combined with MIP method are introduced. Finally, comparison among deadlock prevention policies reported in this chapter is done in terms of structural complexity, behavioral permissiveness, and computational complexity of the resulting supervisor through a typical case study. Importantly, future research directions related to this area are presented at the end of this chapter.