Hierarchical Scheduling of Flexible Manufacturing Systems

Abstract Flexible manufacturing systems (FMS) play an important role in the automation of discrete part manufacturing. Moreover, they are an essential element in the concept of the computer-integrated manufacturing, which is considered to be crucial for the further industrial development. However, the efficiency of a working FMS depends strongly on the quality of the control system. It is well known that the scheduling problem for job shops - the most general production system - is NP-hard, even for simple cases. Therefore, the control problem is usually decomposed into a hierarchical structure according to different time horizons and different objective functions, respectively. In the paper the different mathematical problems and the corresponding algorithms are presented. Finally, we describe a workstation in order to control flexible manufacturing systems, which contains the developed algorithms.