Petri-Net Based Modeling and Scheduling of a Flexible Manufacturing System

In this paper, a timed place Petri-net (TPPN) mode l for fEezible manufacturing systems with the components of machines, limited buffers, robots and the material handling systems, Automated Guided Vehicles (AGV’s} is constructed. Since a firing sequence of the TPPN from the initial marking t o the final marking can be seen as a schedule of the modeled FMS, b y using an A’ based search algorithm, namely, LimitedEzpansion A algorithm, a near optimal schedule of the part processing can be obtained using reasonable computing time and memory requirement. For large volume of parts, we also propose an adaptive scheduling approach to generate a near-optimal schedule in an economical computing time. In order t o show the eflectiveness of the proposed method, a prototype FMS in Automation Lab. of Department of Mechanical Engineering, National Taiwan University, is used as a target system for implementation.