On reference modelling of integrated manufacturing systems using OOA

Abstract

This work advocates the use of Object Orientation as basis of a methodology for creating reference models of manufacturing systems. Work on reference modelling of manufacturing systems integration is reviewed first. Then this work's own standpoint on reference modelling is outlined with definition of the main concepts. Reference models are distinguished from actual-implementation models through the need for generalisation, abstraction and expansion ability. Coad and Yourdon's Object Oriented Analysis is used to demonstrate reference modelling of structural, transformation and procedural aspects of a batchprocessing shop-floor system, explaining how manufacturing systems entities are mapped to OOA entities. The main concepts introduced along with discussion of relevant examples are a phenomenological View, application-related Views, abstraction hierarchy of objects and expansion ability of the model to advance from abstract to environment-specific reference models. Modular instancing of entities is also discussed in the context of further work. KeywordsSystem Analysis, Manufacturing Systems, Shop-floor, Coad-Yourdon's OOA. INTRODUCTIONManufacturing system integration typically addresses many subsystems performing complex sequences of actions, which possibly run concurrently. Cross-area integration in manufacturing systems refers to the specification of common goals, outputs from one area forming inputs to other areas, crossarea consultation between functions, and repercussions of parameter changes in one area onto other areas (Burbidge, 1987 In an effort to design and implement integrated manufacturing systems the concept of reference models has been explicitly or implicitly recognised to be of fundamental importance (Biemans, 1991), (Jochern, 1989), In general, the term 'reference model' describes an 'ideal' or 'target' configuration of a manufacturing system or of parts of it and therefore it has a 'prescription' or 'recipe' connotation. A reference architecture by contrast defines a modelling methodology (rules referring both to the modelled domain and to the modelling task and structures, possibly including a modelling language) (Aguiar, 1995). Another term which is often used in literature as equivalent to a reference model ofa high level of abstraction is 'generic model', e.g. in a production control context (Filip, 1993).According to one classification, there are four main types of use of reference models for manufacturing systems: Benchmarking, Diagnosis, Design, Evaluation (Bohrns, 1993).A CIM Reference model in the context of process industries is given in (McCarthy, 1990). It consists of a number of sub-models, namely organisational, control strategy, information flow and network connectivity used to derive the functions needed in a plant information systemIn designing automated production control systems, system aspects captured by a reference model are categorised as behavioural, information and functional (Lhoste, 1993). A 'diachronic' system life cycle is advocated, using the equivalent of ...

Teaching Manufacturing Systems Integration through Data Modelling and Network Exchange Simulation

“…The term 'reference' characterises the fact that commonly agreed data have to be defined for communication among the six main functions of a manufacturing system [15]. These data may have to be mapped to actual data used by the functions of a real-world manufacturing system.…”