Abstract
A comfortable man-machine interfaces are required for current advanced systems. Keyboard switches as one of the most frequently used man-machine interfaces should provide comfortable feeling for operation. This paper aims at investigating the relation between reaction force of keyboard switches and human switch operation feeling.
We investigate how each reaction force of switches effects to the touch feeling of keyboard switches via sensory test. We made a switch that is assisted by a servo mechanism and can generate arbitrary reaction force characteristics for the sensory test.
The results of factor analysis for the questionnaire data obtained in the sensory test show that the most substantial factor is the feeling expressed by the words “Clear”, “Smooth”, “Stiff”, and “Clicking”.
Further quantitative relations between the reaction force and feelings are obtained by regression line for the questionnaire data. This quantitative relation provides a sensory guideline for keyboard switch design.
Finally, each feeling described by each word is directly evaluated by reaction forces or vice versa on dual scales. The dual scale for reaction forces and degree of feeling can be directly used for designing comfortable keyboard switch.
