AbstractIn this paper conserved nets, which are a subclass of Petri nets, are proposed to facilitate the modelling, analysis, and simulation of flexible manufacturing systems (FMS). Conserved nets ensure that a Petri net model has the property of conservativeness. FVom the structural characteristics of conserved nets, liveness conditions are easily obtained. Although hardware components of FMS are modelled using conserved nets, real-time decision systems are separately modelled from the analysis results of the conserved Petri net model. The modelling and simulation procedure is demonstrated with an example machine centre.