Pre-allocation and partition of buffers for deadlock control in flexible manufacturing systems

In order to make a live flexible manufacturing system (FMS) in which resources and buffers are shared, Liu et al. used the buffer pre-allocation rule to greatly reduce deadlock states and proposed a buffer partition policy to forbid the remaining deadlock states. They also defined a subclass of Petri nets called resource-shared assembly net with buffers (RSANB) to characterize the rule and policy. Nevertheless, only one resource in the FMSs modeled by RSANB can be used in each step in their policy, so its modeling power is limited. This paper indicates that the buffer pre-allocation rule and buffer partition policy can also be used to prevent deadlocks in FMSs in which multiple resources can be used in each step. Subsequently, an extension of RSANB, called extended resource-shared assembly net with buffers (ERSANB), is defined to show the extended application of this rule and policy. Finally, its application is demonstrated by an FMS example.