PETRI NETS Application In Manufacturing System Operations

Introduction

Concurrent and Distributed systems are mostly difficult to manage, know and raise the possibility of incidence of mistakes. These faults or mistakes crop up fairly frequently and thereby it to be quite essential to devise several mechanisms for ignoring the possibility of such mistakes. One technique of cutting down the cost and duration of the design or implementation process is to employ the formal techniques of Petri net and hence avoiding the mistakes by utilizing a few of its qualitative properties. We know that timing in a Petri net is not deterministic and it is often characterized by a probability distribution function of a random variable and therefore the concept of stochastic net systems was initiated. The usually approach to consider this approach is transition timed firing models. Additionally, Petri nets can be presented also as a queuing network along with a semantically easy and formal way of introducing synchronization between the queues.

A top down modelling approach is followed in Petri nets via expanding the net to comprise detailed explanation of manufacturing cell operations. In this section, this approach is adopted in modelling an FMS. Hence we need several additional units or elements to explain the transformed Petri net. Additionally to basic elements of Petri a net that is, places, directed arcs, transitions, and tokens or inhibitor arcs and abstracted places are comprised to facilitate the complicated systems modelling. A top down modelling approach permits abstraction of detailed levels in a concise presentation. In the Petri net theory, a triangle presents an abstracted place.