A universal design method that considers variability in user requirements: A case study of mechanical pencil design

Abstract

The concept of universal design (UD) has received significant attention from researchers, but it remains difficult for UD designers to reflect the diversity of the users in the product. Previously, we proposed a set-based UD method that considered the diversity of a user’s physical characteristics; however, this method did not take into account the requirements of a diverse set of users. Therefore, the present study proposes a new UD concept that quantitatively incorporates the diverse requirements of various users. Exploiting the concept of an evaluation grid and a set-based design method, this paper explains the procedure of our UD method from the determination of user requirements and design variables to the derivation of design solutions satisfying all users. We choose the problem of designing a mechanical pencil as a case study for our proposed method. Pair-comparison tests of mechanical pencils are conducted, and an evaluation structure diagram for a mechanical pencil is constructed on the basis of the results of this experiment. The importance of the design variables is calculated quantitatively based on the evaluation structure diagram, and the key design variables are determined. After the classification of users, we derive the design-ranged solutions for each group of users and the common design-ranged solutions for all users. Our proposed method successfully derives five types of mechanical pencils that together satisfy all users belonging to various user groups.