Hierarchical Decision Making in Machine Design

This paper considers team decision making in mechanical engineering design, and in particular for decisions based on hierarchical evaluation criteria. We develop the Analytic Hierarchy Process as appropriate for mechanical design teams, and demonstrate that the method is particularly well suited for design problems that involve hierarchical descriptions such as for precision machine tools. The process begins by generating a hierarchical list of criteria that is used to compare different possible decision solutions. These criteria may include a wide range of factors such as cost, reliability, and ergonomics. A relative weighting technique is then used to determine the overall absolute importance of each criterion, in accordance with its position in the functional hierarchy. The candidate design solutions are then evaluated on their ability to satisfy each criterion. Finally, an overall rating of each possible solutions is calculated from the criteria weights and the solution evaluations. Normalization of entries and mathematical consistency are utilized to minimize spurious effects sometimes encountered in group evolutions. The method is illustrated with an industrial case study.