Modeling Complex System Using T-subnet based Hierarchical Petri Nets

Net compression technologies are widely researched to avoid the problem of state explosion. Current researches of transition refinement and subnet abstraction mainly paid attention to preserve different attributes during the transformation, usually led to very strict conditions for the subnet, so that the application of these technologies was limited. Aiming to provide the same service and interface after transformation as original module while less restricts are given, a kind of transition subnet is put forward to model complex manufacturing system. The concept “standardized interface” is presented; transition subnets are classified into different types, the idea of “normalized subnet” is presented; Engineering Subnet is defined and a live and normalized subnet with finite live loopbacks is proved to be an Engineering Subnet. Because of live loopbacks owned by Engineering Subnets, the same interface and service as the original module are reserved after the transformation between an Engineering Subnet and the corresponding transition, mean while fewer preconditions are required for the Engineering Subnet compared with current researches.