MOSES

Model Oriented Simultaneous Engineering System

Category: Type 1 Model

Comments: MOSES is a research project being carried out by two groups, one at the University of Leeds (in the Department of Mechanical Engineering) and Loughborough University of Technology (in the Department of Manufacturing Engineering).

The project is funded by the UK government (in the form of the EPSRC) and several industrial collaborators and has a full title (i.e. That which appears in EPSRC literature) of:

"Exploiting Product and Manufacturing Models in Simultaneous Engineering"

The project is funded for a 3 year duration and started in May 1992.

Project Aims and Objectives

There are three major objectives:

• To provide a Reference Model for CAE systems based on Product and Manufacturing models.

• To identify the information and procedures necessary to support that part of the simultaneous engineering process concerned with concurrent design for function and design for manufacture, and to define and apply a prototype knowledge and software environment.

• To provide Intermediate and End Of Project demonstrations using industrial case studies.

Product Model

A Product Model is a computer representation of product data. Product data describes a particular product. The computer representation of product data requires a product data model, which defines the form and content of product data, and a product model, which contains data which is specific to the particular product concerned. For example, the fact that products have a colour and a name would be defined in a product data model; "blue car" and "red pen" are examples of product models. Product data is the combination of a product model and the corresponding product data model. The product data model provides the meaning of the content and the product model: for example, the facts that "car" is the name of the product and "red" is its colour.

Manufacturing Model

The term Manufacturing Model has been used to define the information model which describes the manufacturing processes, resources and strategies of a manufacturing firm. This information model aims to provide a consistent source of manufacturing information to both users and applications and is key to the successful CAE support of simultaneous engineering. The Manufacturing Model has been defined and partially implemented by the MOSES research group in order to demonstrate that the manufacturing capability of a particular enterprise can be reliably represented. This Manufacturing Model has four levels based on a de-facto standard (i.e. Factory, Shop, Cell, Station) and has been defined independently from any application. The Manufacturing Model is being implemented in the object oriented database DEC Object/DB.

The Manufacturing Model describes and captures the information about the manufacturing situation of a company in terms of its manufacturing facility and capabilities at different levels of abstraction. As the Manufacturing Model will represent the detailed manufacturing capability of an enterprise, and its current manufacturing status, this model will support the formulation of new and better manufacturing business strategies, will facilitate the development of factory models and will potentially be a useful source of information for real time production control applications.

The representation of structured resources and processes allows us to have reliable representation of the manufacturing facilities and their capabilities in terms of process technology and equipment. In addition to this type of information, there is a need to represent the manufacturing strategies, because the strategies are decisions made on the use and the organization of resources and processes (e.g. constraints imposed on the use of a certain type of resource or process). There are two types of decisions which make possible the formulation of manufacturing strategies: decisions made over time which define the structure, capacity and technology of the facilities, and the day to day decisions which determine how to use the facilities and related processes. In the Manufacturing Model, strategies will represent how the resources and processes are structured and used to support the realization of the manufacturing function in order to achieve the manufacturing objectives of a company.

The MOSES group consider formal methods for the description of system concepts and components to be essential for common understanding between developers and system users. A CAE Reference Model is being researched that is based on the Referenced Model for Open Distributed Processing (RM-ODP) and is set into the context of the CIM-OSA architecture. The RM-ODP provides a framework to support the development of existing and new CAE systems by establishing a generic set of viewpoints: enterprise, information, computation, engineering and technology. To guide the development of the Manufacturing Model within the framework of the RM-ODP, the Booch Object Oriented Methodology has been used. The Booch Methodology concepts can be mapped adequately into the object oriented concepts defined by the ODP reference model at the information and computation viewpoints.

In order to exercise and prove the worth of the Manufacturing Model an application is being developed that will undertake design for manufacture using information from both an evolving product model representation and the manufacturing model. The results of the analysis undertaken by the application are stored in the product model. A structure for such information is being researched as are the effects of undertaking design for manufacture, whilst a design is evolving, on process planning.

The Intermediate Demonstration took place on 1st March 1994 at Leeds. It was shown to:

• The ACME reviewers

• The ACME-selected independent reviewers

• A DTI representative

• The project industrial collaborators

It was designed to show how the various work packages of the project had progressed to date. A primary objective, however, was to demonstrate our work on Harmonization which involved providing an underlying software infra-structure running in a distributed heterogeneous environment as well as an integrated data modeling definition (see Product Model and Manufacturing Model).

A diagram of the demonstration is shown here with grey circles representing the software applications written to demonstrate the various areas of research. This diagram can be interrogated for information by clicking on the relevant bit (eg, clicking on the database rectangle will result in information about the database used). After reading the information, click on the Back button at the bottom of the window to return to this diagram.

The Harmonization work package

Objective

The approach used to integrate models during ISS and presently in STEP involve creating a single integrated model. The logistics of this approach mean that one person must coordinate the entire model. For this reason, as the model grows, the approach loses its viability. We intend to consider more practical approaches to the integration of models. To realize or final demonstration the development of models and applications must be coordinated throughout their life-cycles.

Methodology

Harmonization involves the integration of models and applications. To achieve our final demonstration this harmonization must include their implementation in a single environment.

NOTE}: A single environment may include multiple computer programs and languages on a heterogeneous hardware platform. However, all elements of the environment must be linked in some way. Early in the project thought will be given to the nature of the software environment that is required to support the final demonstration.

Although software engineering issues (the lowest three levels of the ODP reference model) will not be addressed by the research program they will have an impact on its outcome. To realize our final demonstration we will have to address issues of software design.