AN FMS SCHEDULING AND CONTROL DECISION-SUPPORT SYSTEM BASED ON GENERALIZED STOCHASTIC PETRI NETS

This paper presents an FMS scheduling and control DSS (decision suppor t system) using generalised stochastic Petri nets (GSPNs) for model re presentation and analysis. The function of the DSS is to assist the FM S operator to search for suitable control strategies that will achieve efficient performance. It can also be called upon in the event of unf oreseen changes in production requirements, component failures, or oth er related contingencies. The GSPN modelling approach is employed beca use GSPNs can characterise random processing times, machine breakdown and repair rates. The GSPN employed in the proposed DSS also incorpora tes dispatching control at conflicting immediate transitions and can b e used to determine various performance measures pertaining to schedul ing and control. An application example of the DSS for the processing of two part types in a three-machine FMS is also described.