A collaborative CPN−Fuzzy modelling strategy for conflict solution in flexible manufacturing systems

Abstract

The increasing usage of Flexible Manufacturing Systems (FMS) poses new challenges, such as conflict situations in manufacturing processes. Therefore, there is a need to implement modelling and control of FMS in order to prevent or deal with such occurrences. However, modelling and controlling an FMS is itself a complex task due to the many subsystems and elements that comprise an FMS. Moreover, the existing high coupling between these subsystems also makes modelling and control tasks difficult to implement. This paper proposes a modelling strategy of FMS, which the decomposes the system into smaller and cohesive subsystems. In such a strategy, a part of the system should be designed to address interlocking issue, based on Petri Nets (PN) model and, collaboratively, the other part of the system should be designed to address sequencing of operations, based on Fuzzy Logic. It enables to perform more complex calculus to decide issues regarding FMSs, considering, optimisation criteria like makespan and idleness system resources. This strategy was used for modelling a simulated factory with 6 machines, composed by input/output buffers, 3 AGVs (Automated Guided Vehicles), a load/unload station and AGVs park.