A FORMAL PROCESS TO SUPPORT RESOLUTION OF FUNCTIONAL TRADE-OFFS IN COMPLEX PRODUCT DEVELOPMENT

摘要

This paper proposes a method to resolve trade-off problems between functionalities, which hinders unconventional improvement of a product. As products have become increasingly complex, it becomes difficult to grasp the whole aspects of a product. In order to resolve trade-off problems of a complex product, it is required to model the product in an appropriate form and to gather knowledge of experts in each domain. Although there have been several models to tackle with this issue, modelling still poses difficulties due to lack of clear guideline. This paper classified models into three types: function-based, cognition-based and physics-based. Then, their roles and description guidelines are clarified. As a function-based model depicts functionality of a product in a rather simple description, it is employed to specify significant tradeoffs. A cognition-based model depicts the designers' recognition of physical phenomena while a physics-based model rigorously depicts the physical phenomena. A cognition-based model is appropriate for ideation while physics-based model contributes to objectivity of a model. This paper proposes complimentary modelling and use of cognition-based and physics-based models. To support ideation of solution to the trade-offs, TRIZ is applied. The proposed method is demonstrated and validated by the case study of Continuously Variable Transmission.