An object-oriented modelling framework for automated manufacturing system

Abstract

Proposed in the paper is an object-oriented modelling (OOM) framework, called a JR-net modelling framework, for automated manufacturing system (AIMS) design. The proposed modelling framework, which consists of a graphical modelling tool called JR-net (job resource relation-net) and a modelling building procedure, is the same as the current practice of AMS design and is based on the OOM paradigm. In other words, a virtual prototype of AMS is constructed step-by step based on a three-phase modelling approach: static layout modelling (object model); job flow modelling (functional JR-net model); supervisory control modelling (dynamic model). A functional JR-net model is a directed graph in which the standard resources of an AMS become nodes and job transfers among the resources become the arcs of the graph. A complete (dynamic) JR-net model is obtained by specifying supervisory control requirements using tokens in the functional JR-net model. The usefulness of the proposed OOM framework is demonstrated by applying it to the modelling of an AS/RS. Also addressed are implementation issues of JR-net models.