Segment-based approach for real-time reactive rescheduling for automatic manufacturing control

We propose a new segment-based approach for a real-time reactive rescheduling method. The approach is applicable to actual large-scale manufacturing systems, such as fully automated semiconductor wafer fabrication lines. The proposed method can efficiently (in terms of computation time) schedule processing operations at equipment units by dividing a wide scheduling range into small segments and by using a greedy scheduling algorithm. It can also reactivate infeasible schedules without sacrificing the quality of schedules in terms of productivity as much as possible. From the simulation results obtained, we experimentally confirmed that the proposed method reactivates, without significant productivity loss caused by the rescheduling algorithm itself, infeasible schedules faster than a comparative method commonly in use today. Consequently, the proposed method manages to keep schedules at each equipment unit executable in terms of processing performance and schedule quality.