Scheduling Cluster Tools with Supervisory Control Theory

The aim of the work presented here is the scheduling of cluster tools, applying a method suited for production processes that have to meet tight time-constraints. In this article, we describe a method for the synthesis of a set of consistent schedules that allow meeting the constraints imposed to the cluster tool. We formulate the problem of verifying temporal constraints in terms of supervisor synthesis problem with a set of specifications within the framework of Supervisory Control Theory (SCT). The method, previously elaborated for the scheduling of repair shipyard operations, has been adapted to cope with cluster tools specificities, i.e. a process that involves short duration operations (the robot moves) as well as long duration operations (the operations on process modules). This method is illustrated on an example of a cluster-tool with multiple constraints.