Modeling and Analysis of an On-Line FMS Scheduler Using Colored Petri Nets
Ali A. Al-Titinchi, Kasim Mousa Al-Aubidy · 2004
An interactive hierarchical model based on colored Petri net (CPN) for generalflexible manufacturing system (FMS) scheduler is presented in this paper. The proposed model is partitioned into two levels to face the complexity of the manufacturing systems. The first level (cell-level) supervises the jobs scheduling between cells. The second level (machine-level) supervises the scheduling of the manufacturing jobs between machines inside the active cells. The goal of the scheduler model is to interpret the output of the manufacturing route planner into graphical representation and to achieve the sequencing, dispatching and monitoring the real time execution of these manufacturing plans. Also, the proposed CPN model generates feedback status to monitor the abnormal conditions. Sub CPN priority structures are embedded in the main model to control the election from the competitive jobs to use the limited resources in the system. The hierarchy organization will enhance the real time response of the sequencing and monitoring capabilities. The designed scheduler has been evaluated for different case studies and the achieved results are very encouraging.