Object-oriented Petri nets for modelling and analysis of automated manufacturing systems
Computer-integrated manufacturing systems
This paper presents an Object-oriented Petri Net (OPN) approach to model and analyse the dynamic behaviours of an Automated Manufacturing System (AMS). Both the basic and the complete OPN models are introduced to represent the generic and specific dynamic behaviours of an AMS, respectively. Based on the basic OPN model, we need to construct the Object Communication Net (OCNet) for each physical object, and then employ the theory of invariants to perform the deadlock analysis. For an analysed
... -deadlock basic OPN model, the complete OPN model for a specific AMS may be effectively derived from it by only including those related system constraints (e.g. part routing, resource capacity), since the basic OPN class library is reusable. A conflict ana/ysis approach is then introduced to identify all the conflicting events involved in the complete OPN model, so that the most suitable control/decision strategy for resolving each conflict event may be suggested. Consequently, a rule-based control software may be implemented directly from the specification of the validated complete OPN model by following a number of transformation rules. Copyright @ 1996 Published by Elsevier Science Ltd Kc~words: Ohjcct-oriented method. Petri net. manufacturing control model 23 D'Souza, K A 'A control model for dctccting deadlocks in an automated machining cell'. Computers Ind. t-kg., Vol 26 No I (19Y4) pp 133-139 Peterson, J I, Petri Net Theory and the Modeling of Systems. Prcnticc-Hall, N.l (1981) Jenson, K 'Colourcd Petri nets and the invariant method'.