Richard H. Weston

The complementary use of IDEF and UML modelling approaches

The IDEF and Unified Modelling Language (UML) modelling approaches have become popular in industrial and academic circles. IDEF comprises a suite of graphical modelling techniques designed to formally specify and communicate important aspects of enterprise engineering projects, whereas UML is a modelling language that can be used to generate computer-executable models that encode key aspects of software engineering projects.This paper considers similarities and differences between IDEF and UML modelling approaches. It is observed that the combined development and reuse of IDEF and UML models has the potential to place information technology (IT) systems engineering projects into a wider context of enterprise engineering. An electronics industry case study is described to illustrate this observation. Particularly, this study illustrates how semantic information encoded by different types of IDEF diagramming technique can be re-represented and reused as models expressed in alternative notations. The study illustrates benefits gained from using IDEF as a business front end to UML. Further, it indicates how consistency can be maintained between multiperspective models expressed in terms of general purpose IDEF and UML modelling constructs.

Distributed engineering of manufacturing machines

Abstract The specification and deployment of enterprise modelling and component-based system concepts to facilitate the distributed engineering of automotive manufacturing machines is reported in this paper. The main areas of research reported in the article cover (a) the design and prototype development of new forms of component-based engine assembly and transfer machines (b) life cycle engineering approaches that improve the change capability of component-based automotive machines and (c) the design and implementation of an engineering environment that enables distributed engineering teams to achieve (a) and (b). The concepts, approach and environment have been developed and are being formally assessed with reference to current practice within an ongoing engineering programme. A consortium of leading automotive companies is collaborating on the research project with the aim of producing a new range of engine products that will be used in various makes of vehicle around the globe.

Modelling dynamic value streams in support of process design and evaluation

To remain competitive, most manufacturing enterprises (MEs) need cost-effective and responsive business processes with capability to realise multiple value streams specified by changes in customer needs. Models of MEs can play a critical role in enabling enhanced enterprise process and systems design and change based on analysis of their performance, and ongoing management and control of their operation. Typical models of MEs can provide reusable computational representations of organisational structures, processes, information, resources and related value flows in an enterprise. This paper presents a dynamic modelling approach to value stream mapping which enhances current best practice when reasoning about changing process and resource systems requirements. Here, coherent use of enterprise and simulation modelling techniques were deployed to develop value streams of a case study enterprise which is a make-to-order furniture manufacturing SME. The paper explains how models created during the modelling stages were validated and reused as a basis for informed SME decision making in relation to product realisation strategies and related organisation design and change decisions and actions.

An implementation of the business process modelling approach in the automotive industry

Abstract The development and application of a business process modelling approach to comprehend, formalize, simulate and assess a particular domain within the automotive industry are described in this paper. Within an ongoing project carried out by Loughborough University, the design and implementation of a new generation of component-based machine control systems are being investigated. As part of this project, impacts of business and technical aspects of the new control systems on existing practices are also being examined using enterprise modelling methods and tools. The modelling has been applied to the production and assembly of a machine for a new engine project in the automotive industry. The modelling approach has been based on the CIMOSA modelling architecture and complementary simulation and analysis tools, mainly ithink™ and Excel. The lessons learned from the implementation of the modelling approach and the assessment of the component-based machine control systems are also discussed in this paper. The criteria of this assessment were considered primarily as cost and time, although other factors that ultimately impact on the business processes are also discussed.

Steps towards enterprise-wide integration: a definition of need and first-generation open solutions

Abstract The need is described for an architectural framework which unifies the use of an open systems integrating infrastructure and a modelling framework to enable wider-scope CIM systems to be designed, implemented and maintained. In addition, an industrial case study use of the CIM-BIOSYS integrating infrastructure is reported to highlight the benefits of its use, particularly in terms of the ability to manage and support inherent integration processes in a highly flexible, extendible and maintainable manner.

Digital servo motion control of air motors

Aspects of the operating characteristics of pneumatic systems are given and control methods for pneumatic servo motors are described. Both analytical and experimental approaches are considered. The results show that digital-controlled air motors have the potential of providing an alternative solution to their electric and hydraulic motor counterparts. Air servo motors, through inherent low cost, good power-to-weight ratio and intrinsically safe operation, can thus be utilized to control industrial machines in certain application areas.

Computer Controlled Pneumatic Servo Drives

This paper describes how microprocessor-based controls can be used to produce low cost pneumatic servo drives which could find wide application in manufacturing industries. The approach incorporates digital compensation for system non-linearities so that, when positioning loads in a ‘point to point’ mode, it is possible to achieve a significant improvement in both the static and dynamic performance of the drive. For the compensation algorithms implemented a theoretical foundation is presented based on a linearized model of pneumatic drives. The paper also describes how microprocessor-based hardware and software have been constructed to evaluate performance criteria. This test facility has allowed the software implementation of the compensation algorithms to be refined so that satisfactory performance can be achieved with both translational and rotational drives utilizing various forms of transmission. The test facility has also allowed various control system elements to be evaluated so that pneumatic drives suitable for industrial application, can be specified.

On modelling reusable components of change-capable manufacturing systems

Abstract New modelling constructs are defined to enable human, machine, and IT resource systems to be described coherently and explicitly as ‘reusable’, ‘change-capable’ ‘components’ of manufacturing enterprises. These components are referred to as ‘dynamic producer units’ or DPUs. DPU characterization is designed to facilitate: graphical representation of resource systems; explicit specification of resource systems; and implementation description of resource systems that can be computer executed within simulation modelling environments. Also described is a methodological use of the DPU modelling constructs, which shows how they can complement the use of ISO enterprise modelling and proprietary (discrete event and continuous) simulation software. By so doing, the modelling of responsive production systems is enabled, where such systems comprise user defined configurations of process networks, resource systems, and time-dependent flows of units of work. This modelling method enables decomposition and semantically rich representation of complex systems composed from interoperating DPUs that can be computer exercised within specific organizational contexts. This paper introduces the DPU and illustrates its systematic application when designing responsive production systems.

An approach to modelling dependencies linking engineering processes

Abstract A multiperspective modelling method is described that was developed and used to support an international consortium of businesses concerned with realizing automobile engine production on a global scale. The modelling method provides a capability of documenting, communicating and analysing various dependent aspects of multiple threads of engineering activities. Commercially available and specially developed computer modelling tools have been deployed to operationalize the method, and thereby to facilitate the design of dependent activity flows, the resourcing of activity flows by suitable human and technical systems and the control and management of workflows. The paper outlines requirements of the method, with reference to properties of engineering processes that needed to be modelled. A prime focus of attention was on engineering a new generation of component-based manufacturing lines suitable for the ‘mass customization’ of automotive engine products in production plants around the globe. Key features of the modelling framework are described, as are the stages of modelling and the associated use of proprietary modelling tools. Also provided are examples of models generated when using the method and tools.

The enhanced use of enterprise and simulation modellingtechniques to support factory changeability

Bearing in mind that activity requirements of manufacturing enterprises (MEs) can usefully be described as a network of dependent processes, the current paper identifies complementary properties of state-of-the-art enterprise modelling and simulation modelling techniques. It is observed that, when these techniques are used in a coherent fashion, they have potential to create semantically rich models of process networks that can be computer-executed so as to replicate and/or predict organizational behaviours. The current paper describes an outline of how a particular choice of well-proved enterprise modelling and simulation modelling techniques can be used in an integrated fashion. Also described are interim research findings when using such an integrated modelling approach in a case study furniture making company. For key segments of business processes currently deployed by the case study company, the outcome has been new qualitative and quantitative understandings about (a) alternative ways of organizing multi-product flows through a constrained (in situ) set of human and technical resources and (b) potential performance enhancements that could be achieved in process segments by purchasing, commissioning and deploying alternative systems of human and technical resources. Research groundwork is now in place to support the case study company as in the future it makes (a) medium-to-long term investment decisions about new manufacturing control strategies and the purchase of new resource systems and (b) short-to-medium term production planning and control decisions.