Combined buffer pre-allocation and siphon control for deadlock prevention in Petri nets

We study the design of deadlock prevention for a special class of flexible manufacturing systems (FMSs). In such FMSs, each machine has its own input and output buffers and multiple resources can be used in one step. As proved in this paper, by pre-allocating and partitioning all buffers in an FMS, deadlocks can be prevented. To demonstrate this policy, two subclasses of Petri nets, denoted by MRSNB and MRSANB, are defined. Furthermore, on combining buffer pre-allocation and siphon control, two deadlock prevention approaches for such FMSs are proposed. Compared with other reported methods, the two proposed approaches can achieve a satisfactory trade-off among permissiveness, structural simplicity and computational complexity. Several typical FMS examples are used to illustrate the proposed concepts and policies, and to show the advantages over other methods.