Influence of skin hydration on fingertip mechanical response and tactile perception

Details

Supervisors

Delhaye, Benoit

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

enTouch is one of the most fundamental components of daily life, allowing meaningful interactions with our environment through tactile feedback. Tactile perception has been widely studied due to its complexity and importance. It covers the ability to detect edges, surfaces, roughness, smoothness, and much more. This thesis focuses on the tactile perception of microscale features. While previous studies have shown that humans can detect microscale features under controlled conditions, the roles of contact force, skin hydration, and local skin deformation have not been fully explored in controlled passive-touch settings. To adress this, 21 healthy participants took part in a passive tactile detection experiment using a two-alternative forced-choice (2AFC) method. The study explored detection limits for microscale features using passive single-contact events, the effect of glycerine induced hydration on detection, and the relationship between local fingerpad deformation patterns and detection outcome using digital image correlation (DIC) analysis. Results confirmed that humans can detect microscale features under passive contact, though detection thresholds were slightly higher than expected. Glycerine application increased fingertip friction but did not affect hydration nor detection. However, imaging, revealed more pronounced skin deformations around microscale features under high hydration levels tending to confirm the link between skin mechanical behavior and moisture.