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A SOAR-based computational model of mechanical design Public Deposited

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  • Considerable progress ha been made in Computer-Aided Design (CAD) techniques to assist Mechanical Engineers in the detail design stages and adaptive redesign tasks. Currently, CAD tools support the designer in system layouts, sizing of components, drafting, analytical calculations, generating NC machining data and even motion or energy simulations. However, the more critical tasks of conceptual and early layout design have not been facilitated by these computer tools. The primary reason for this is the lack of understanding of the mechanical design process and what actually goes on in the designers' mind in these stages. An empirical approach to studying the mental processes of designers, using protocol analysis, was recently undertaken by Ullman, Stauffer, and Dietterich. The work described in this paper attempts to translate some results of that study of mechanical engineering designers to a more formal and detailed level by building a computational model of the design process. The main contribution of the present work is a control structure for the design model proposed by the protocol study. A computational model of Design, even at an incomplete level, can take us closer to an understanding of the Design Process. For the construction of such a model, it is required to formalize the knowledge involved, the processes, and their interconnections. Like any expert system knowledge base, the pieces of domain knowledge (separate from the control knowledge) used in design have to be identified. The difficulties in building such a model can help to bring forth the deficiencies in the protocol analysis method and suggest improvements. The model can serve as a basis for testing representation techniques for the design knowledge and assessing their adequacy. Similarly, appropriate software architectures needed for incorporating the control strategy of the design process can be studied or developed. The control structure of design, used for the computer model can be refined with further empirical studies. It could be used as a basis to verify and represent future protocol analyses and other design methodology studies. Once a competent theory of design methodology is developed, computer algorithms and other tools can be formulated to support the routine parts of conceptual design. There could be better integration of CAD systems and design knowledge. CAD systems could be made more productive by understanding the intentions of the designer, detecting errors, suggesting alternatives, and answering design queries. Progress made towards such a formal model may also have potential applications in other fields of Engineering.
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