Strategy to Operate Cylindrical Interface-Operation Difference According to the Dimension of the Cylinder and That of the Hand

In this article, we study how users determine the way to operate cylindrical interfaces (lever, switch, etc.) according to their dimensions, shape, and the user's hand dimensions. With a target of avoiding control failure, it is important to estimate user's intuitive operation of a given interface from design. Eight subjects were observed operating different cylinders with various height and diameter. The boundary between the tilting operation and other operations was found to be related to an aspect ratio; the ratio of the diameter to the height. The boundary between the sliding operation and rests was determined by a comparison of hand width with cylinder height. The boundary between the pushing and rotating operations was thought to be related to the length of the distal phalanxes of the fingers.