The effect of surface roughness on human stiffness feeling

This study aims to elucidate the effect of surface roughness on feeling of stiffness. In order to clarify the effect of surface roughness, we focus on the fingertip motion during the sensory evaluation of stiffness feeling. In this paper, the pair comparison method was used in sensory evaluation with two kinds of instruction. One is that subjects evaluated stiffness of samples freely. The other is that subjects evaluated them with feeling the surface roughness. During the sensory evaluation, subject's fingertip trajectories and contact force with the samples were measured. From the results of sensory evaluation, it was found that surface roughness obviously affected feeling of stiffness in the case of instruction that subjects evaluated them with feeling the surface roughness.