Object-oriented methods for the design of automated manufacturing systems
Abstract of thesis entitled
Object-oriented Methods for the Design of Automated Manufacturing Systems
Wong Tak Wah
for the degree of Doctor of Philosophy
at the University of Hong Kong
in January 1998
In recent years, the manufacturing industry has been faced with an upsurge of international competition and also turbulent market conditions. As a result, automated manufacturing systems (AMS) have been employed by many manufacturing enterprises as an effective means to produce a variety of quality products within the shortest possible lead-times, and with minimal re-configuration efforts. The objective of the present research, therefore, is to develop methodologies to generate object-oriented system design specifications in the design of AMS. Indeed, the specification stage is the crux of system development, for ensuring a precise description of system design requirements, so as to avoid huge financial losses arising from problems in the design and development processes.
In this research, an object-oriented system specification methodology is proposed as an alternative to the conventional system design specification approaches for AMS, with a view to generating a complete and precise system design specification. This methodology consists mainly of a conceptual model of a manufacturing system, a specification framework, and a specification procedure, and can capture the requirements in the structural, informational, and behavioural aspects of an AMS within an integrated framework. The four modelling techniques used in the methodology, namely, the object diagram, the rule-based representation method, the action rule diagram, and the event flow diagram, can help to extend the capability of the conventional object-oriented approach in specifying an AMS. The result is the
introduction of three improvements. Firstly, the behavioural specification of an AMS can provide an integrated view of the system in terms of processes, to allow integration problems in design to be detected at an early stage. Secondly, the control policies incorporated into the informational specification can generate a more complete system design specification to satisfy the system control requirements, thus facilitating the design of control subsystems. Thirdly, the clear distinction between the structural and the informational specifications of an AMS facilitates the modification and reuse of system design specifications.
Another major concern of this research is the development of an object-oriented prototyping method to ease the verification of the system design specification against its original customer requirement specification. Considerable emphasis is placed on representing explicitly the semantic information of the system design specification, to establish a direct correspondence between the prototype and the system design specification. An extended frame-based representation method is proposed and used in the development of an object-oriented prototyping tool to realise this direct correspondence. The resulting prototyping tool can support the streamlining of the prototype creation, verification, and design modification processes. In addition, the design changes suggested at this prototyping stage can be incorporated easily into the system design specification.
The proposed object-oriented system specification and prototyping methods are applied to generate the system design specification of an FMS, with special emphasis on capturing the system control requirements. The results of this case study show that the proposed object-oriented specification and prototyping methods indeed provide a convenient means to generate a comprehensive system design specification conforming to the original system requirements of customers, and to cope with changes in system requirements both during the design and the subsequent redesign stages.
School:The University of Hong Kong
School Location:China - Hong Kong SAR
Source Type:Master's Thesis
Keywords:computer integrated manufacturing systems design and construction object oriented programming science
Date of Publication:01/01/1998