Effect of Layer Compliance on Frictional Behavior of Soft Robotic Fingers

In this paper, the modeling and design for frictional loads applied by robotic fingertips through soft contact interface are investigated. The dependence of the sustainable friction forces and moments due to the normal load applied on the contact area is studied. A model that considers the dependence of both the contact area and the coefficient of friction on the application of normal load is proposed. Specimens of simplified fingertips, made with different materials and shaped with different thickness of the covering soft layer, are tested in order to validate the proposed model via designed experiments. The results obtained have very important relevance on the design of robotic hands and fingers equipped with soft pads or skins, and can help on the choice of suitable features for the different layers of contact pads or skins