An Integrated Environment for Computer-Aided Control Engineering

This thesis considers the construction of a system to support the total design cycle for control systems. This encompasses modelling of the plant to be controlled, specification of the final ob­ jectives or performance, design of the required controllers and their implementation in hardware and software. The main contributions of this thesis are : its development of a model for CAD support for controller design, evaluation of the software engineering aspects of CAD development, the development of an architecture to support a control system design through its full design cycle and the implementation of this architecture in a prototype package. The research undertakes a review of general design theory to develop a model for the computeraided controller design process. Current state-of-the-art packages are evaluated against this model, highlighting their shortcomings. Current research to overcome these shortcomings is then reviewed. The software engineering aspects to the design of a CAD package are developed. The char­ acteristics of CAD software are defined. An evaluation of Fortran, Pascal, C, C++, Ada , Lisp and Prologue as suitable languages to implement a CAD package is made. Based on this, Ada was selected as the most suitable, mainly because of its encapsulation of many of the modern software engineering concepts. The architecture for a computer-aided control engineering (CACE) package is designed using an object-oriented design method. This architecture defines the requirements for a complete CACE package including control-oriented data structures and schematic capture of plant models. The details of a prototype package using Ada are given to provide detailed knowledge in the problems of implementing this architecture. Examples using this prototype package are given to demonstrate the potential of a complete implementation of the architecture. Digital Equipment Corporation