Impact of humidity on the biomechanical properties of the finger's skin

The manipulation of objects is everywhere present in our daily life. Taking the environment into account, our finger’s humidity impact such movements. However, the mechanisms underlying our ability to perform the most optimal movements under such conditions are complex. The objective of this work is to calibrate a new moisture evaluator and to focus on the impact of humidity on the main biomechanical properties of the fingerpad such as friction, contact area, and deformations. Three different initial humidity conditions allowed us to observe the interaction between the moisture level and the normal force, friction, contact area, and deformations. Using the calibrated results from the MeV2 probe, a maximization of friction results from a medium humidity level and a medium contact areas ratio. The normal force also plays an important role during static and dynamic contact, as well as the occlusion phenomenon, increasing the moisture content of the fingerpad. Such results bring a new dimension to the previous research taking online values from the MeV2, which suggests avenues for reflection on the study of object manipulation.