Yoshihiro Yao

A new approach on CPS-based scheduling and WIP control in process industries

The cyber-physical system (CPS) concept is now attracting attention in systems engineering. We attempt to apply CPS to a fully automated factory management and control in processes such as semiconductor fabrication. We propose a novel structure, designated as a real-virtual integrated system, based on the CPS concept, and construct manufacturing scheduling and WIP control. It is designed to follow current dynamic changes and large future fluctuations at production sites simultaneously by executing dynamic scheduling of the real system and by simulation of the virtual system interactively. The effectiveness of the proposed scheduling method can be examined more accurately for possible adaptation to a shop floor.

A study on automated scheduling methodology for machining job shop

In this study, scheduling method using a combination of auction-type real-time scheduling and simulation is proposed in order to automate the scheduling for machining job shop. The control mechanism which is essential for executing real-time scheduling and simulation simultaneously has been developed and implemented. The auction algorithm for the real-time scheduling which improves the delay of delivery date and amount of setup time at the same time is investigated. Also the method of simulation during the real-time scheduling which can predict the changing situation of the shop and automatically take countermeasures by adjusting the scheduling precondition is discussed. It is clarified that the proposed system has the ability to automate machining job shop scheduling.