Flexible manufacturing system structural control and the Neighborhood Policy,part 1. Correctness and scalability

IIE Transactions - Structural Control Policies (SCPs) are real-time flexible manufacturing system (FMS) operating policies that guarantee deadlock-free operation. SCPs must be correct and scalable....     

Flexible manufacturing system structural control and the Neighborhood Policy,part 2. Generalization,optimization, and efficiency

In the first of this pair of papers, the Neighborhood Policy was shown to be a correct and scalable Structural Control Policy (SCP). Operating constraints that guarantee deadlock-free flexible manufacturing system (FMS) operation are generated based on machine capacity. For some systems these constraints appear to be quite conservative. This paper generalizes the Neighborhood Policy so that many different SCPs can be generated for the same FMS configuration. A method of finding permissive neighborhood systems is then developed. Finally, SCP efficiency is defined and investigated for Capacity-Based and Optimal Neighborhood Policies.     

Celeritas: a coloured Petri net approach to simulation and control of flexible manufacturing systems

In many areas of computerization today, the capabilities of hardware systems far exceed the sophistication of software systems needed for optimum control. This research is an attempt to advance software control capabilities of flexible manufacturing systems (FMSs). To this end, an FMS controller architecture, called Celeritas, has been designed and a software system conforming to this architecture has been designed and implemented. Celeritas is a generic, data-configurable FMS controller designed using the coloured Petri nets (CP-nets) modelling paradigm augmented with decision support software to provide both FMS simulation and control. Formalisms of the CP-net paradigm provide straightforward representation of both the inherent concurrency and resource conflicts present in such a complex system. Augmentations provide user-defined routines for real-time interfaces to this information which is utilized to provide resource arbitration services among jobs competing for scarce resources and overall job scheduling.