Software Patterns for Modelling Discrete-Part Manufacturing Systems Using Objects

A manufacturing system consists of entities that relate to one another through some type of transaction. Entities exhibit specific behaviours. The essential modelling problem is to reproduce the aggregate effect of individual behaviours, typically by representing all the relevant entities, their behaviours, and their transactions. Simulation software provides the means for creating, executing, and observing these representations. While modern simulation languages provide many useful modelling constructs, they suffer from several limitations in modelling manufacturing systems. These include having incomplete or inconsistent mapping of software abstractions to the system being modelled, having limited modules for representing decision-making, and not being able to explicitly accommodate human supervisory control. In this article we discuss the development and application of an object-oriented architecture for manufacturing modelling and simulation. The architecture is derived from an explicit domain analysis of discrete-part manufacturing systems from a material flow perspective, and provides software patterns for representing entities and their interactions. The architecture also supports the development of real-time, interactive simulations of manufacturing systems with a high degree of fidelity, incorporating supervisory control, and it provides software abstractions for representing manufacturing decision-making and control.