Constraint-Aided Conceptual Design

The product development process is concerned, not only with the design of products, but with how these products are manufactured, distributed and serviced. Engineering conceptual design can be de ned as that phase of the product development process during which the designer takes a speci cation for a product to be designed and generates many broad solutions to it. Each of these broad solutions is, generally, referred to as a scheme. Each scheme should be su ciently detailed that the means of performing each function in the design has been xed, as have any critical spatial and structural relationships between the principal components. While it is generally accepted that conceptual design is one of the most critical phases of the product development process, few computer tools exist which provide support to designers working in this stage of product development. The thesis defended in this dissertation is that constraint processing o ers a rich basis for supporting the human designer during engineering conceptual design. A new perspective on the conceptual phase of engineering design is presented, upon which a constraint-based approach to supporting the human designer is developed. This approach is based upon an expressive and general technique for modelling: the design knowledge which a designer can exploit during a design project; the life-cycle environment which the nal product faces; the design speci cation which de nes the set of requirements that the product must satisfy; and the structure of the various schemes that are developed by the designer. A computational reasoning environment based on the notion of constraint ltering is proposed as the basis of an interactive design support tool to assist a human designer working in the conceptual phase of design. Using this interactive design support tool, the designer can be assisted in developing models of proposed schemes which satisfy the various constraints that are imposed on the design. The primary contribution of this research is that it provides a novel approach to supporting the human designer during the conceptual phase of engineering design. The approach presented here not only addresses the issue of modelling and reasoning about the design of products from an abstract set of requirements, but it also demonstrates how life-cycle knowledge can be incorporated into the conceptual design of a product and how alternative schemes can be compared. xii Declaration This dissertation is submitted to University College Cork, in accordance with the requirements for the degree of Doctor of Philosophy in the Faculty of Science. The research and thesis presented in this dissertation are entirely my own work and have not been submitted to any other university or higher education institution, or for any other academic award in this university. Where use has been made of other people's work, it has been fully acknowledged and referenced. Barry Alan O'Sullivan July 1999. xiii Dedication This dissertation is dedicated to my mother, for always being there. xiv Acknowledgements I would like to extend my warmest gratitude to my PhD supervisor, Professor James Bowen, for his help and encouragement while I carried out the research presented in this dissertation. In particular, I would like to thank him for the time he spent helping me to present my research and thesis in the form of this dissertation. I would like to thank my partner in love and life, Linda, for always being there for me while I completed this research. Her love has been a constant source of inspiration to me. I would like to thank Frank Boehme and Chris Dornan for the all the advice on LATEX. Also, I would like to thank my fellow members of the Constraint Processing Group, Alex Ferguson, Peter MacHale, Marc van Dongen and Steve Prestwich, for the many interesting discussions on constraint processing, but in particular, for just being good friends. I would like to thank Maurice O'Brien, Pat Doyle and Mel Conway, of Bourns Electronics Ireland, for their assistance with the industrial case-study that was carried out at their company. I also wish to acknowledge the support of the European Commission and their funding of the \Concurrent Engineering Design Adviser System" (CEDAS) project (Esprit Project 20501) and the Integration in Manufacturing and Beyond (IiMB) Subgroup for Design Coordination (Esprit Working Group 21108). My involvement in these activities was a very valuable source of inspiration for the research that I present here. Finally, I would like to extend my deepest thanks to my family: my mother, Joan; my father, Noel; my brother, Brian; my sister, Carmel; and my brother-in-law to be, Anthony. They are a constant reminder of what is truly important in life. xv Chapter