Energy-Efficient Scheduling of Flexible Manufacturing Systems Based on Petri Net

Flexible manufacturing systems (FMSs) are expected to provide flexibility and efficiency to satisfy the needs of high-variety production of low-volumes. On the other hand, in the current global market competition and energy crisis, reducing energy consumption while maintaining high and flexible productivity is a big challenge for the manufacturing industry. In this paper, a framework for FMS energy-efficient scheduling is proposed. A specific type of petri net model i.e., timed & energy transition petri net (TETPN), is developed for modelling the dynamic production process of FMSs. A TETPN enables model both time and energy characteristics of production operations during manufacturing. A step-wise heuristic algorithm based on hybrid beam search is modified for generating the reachability graph of TETPN. Then an energy-efficient schedule is obtained using the proposed framework. A study case of an FMS producing different types of products is adopted to illustrate the proposed methodology. The results show the efficiency of energy-efficient scheduling of FMSs can, indeed, be achieved.