A virtual factory based approach to on-line simulation and scheduling for an FMS and a case study

The recent years have witnessed a revolution in computing capabilities. At the same time, modern manufacturing systems are becoming increasingly compl ex and capital-intensive. Here, we propose a virtual factory wherein an eff icient prototyping testbed will be provided. It will be possible to develop detailed models to support system design and operation, to test different system configurations. Besides, It will be possible to manipulate all syste m features which impact performance, and to see the results of these manipu lations, all without disrupting the actual system. This paper is one among very few that tries to represent the virtual factory in an analytic form so that many existing mathematical analyses can be applied. New pseudo resour ces can be added to form a new virtual environment, and control policy desi gned by engineers will be evaluated before being issued. Since a state-tran sition sequence of the virtual factory from the initial state to the final state can be seen as a schedule of the modeled system. An effective schedul e of the processing can be obtained by using an A\ast based search algorith m, namely, Limited-Expansion A algorithm.