Flexible Manufacturing System Modeling: A Petrinet Based Survey Approach

Flexible manufacturing system (FMS) is the one, which can be changed or adapted quickly to manufacture different components or products at different volumes of product. Flexible manufacturing system includes – a set of flexible machines, an automatic transport system and a sophisticated database with decision support system, to decide at each instant what is to be done on which machine. The objective of Flexible manufacturing system is to provide both machine flexibility and routing flexibility. In large flexible manufacturing system there are number of independent subsystems, and essential element of integration is through computer based system. Also, a detailed planning for successful coordination of complex subsystems highlights the importance of modeling of FMS. Petrinets are a set of nodes, arcs and well known for their modeling potential. These systems have significant ability to implement optimization techniques and are mainly used for modeling manufacturing plants as discrete event systems. In petrinet the two types of nodes are places and transitions, which represent the state of the system and the occurrence of events, respectively. In manufacturing systems, places would represent operations like process, transportation, reparation and transitions signifies events, such as termination of a job processing or a machine breakdown. Arcs are directed, and connect transitions with places. Tokens exist in places and represent the truth of the condition related with such a place. The firing process induces a token’s flow among places. when a transition fires, tokens from all its input places are removed and put into the transition output places. A transition can only be fired if it has sufficient tokens at its input places. The main objective of this study is to carry out a detailed survey of Petrinet based modeling approaches to flexible manufacturing system. 742 Jacob John and M B Kiran