An effective loading rule for FMS real time scheduling

FMS real time scheduling requires the concurrent solution of both loading and despatching problems. The loading strategy is the most critical and important scheduling decision in an FMS. Presents an effective loading rule (job‐group loading rule), based on experimental observations: a group of jobs, reflecting the ratios of the production mix, is loaded on the input warehouse every time that it is completely empty; all the jobs loaded on the input warehouse have to be accessible for the material handling system. Demonstrates how this job‐group loading works as a dynamic rule for real time scheduling of manufacturing systems, defining a part releasing policy able to guarantee reaching a periodic, steady state production. The capability of the job‐group loading rule has been verified when the FMS characteristics are closest to a real situation. Analyses the effects of the interferences on transport operations, the variability of machining times, the finite capacity of interoperational storage and the stops for preventive maintenance or breakdown. Research results show the capability in FMS management of real time scheduling based on the job‐group loading rule.

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