Abstract
It is important to evaluate the mechanical characteristics of the fingertip, which is one of the factors affecting the tactile sensation. In this paper, to elucidate the relationship between perception characteristics of the roughness feeling and mechanical characteristics of the fingertip with different moisture conditions, we first set three conditions of fingertip moisture content: standard, wet, and dry. Next, the average thickness and Young's modulus of the stratum corneum were measured by fingertip mechanical characteristics measurement system using an optical coherence tomography (OCT). The stratum corneum thickness of the fingertip is detected from tomographic images. Young's modulus of the stratum corneum of the fingertip was calculated from the pressing force measured by load cell, stratum corneum thickness detected from the tomographic image, and the contact area between the finger and glass plate. Finally, vibration amplitude detection thresholds were measured under each moisture condition using a vibration presentation device. Six different vibration frequencies were used for the vibration amplitude detection threshold measurement. As a result, it was clarified that the thickness of the stratum corneum increased and Young's modulus decreased when the moisture content of the fingertip decreased. It was also confirmed that the threshold for detecting high-frequency vibration was lowered as the moisture content of the fingertips changed.
