  The complex physics behind electroadhesion-based tactile displays poses an
enormous modeling challenge since not only the fingerpad structure with
multiple nonlinear layers, but also the roughness at the microscopic scale play
a decisive role. To investigate tactile perception, a potential model should
also offer the possibility to extract mechanical stimuli at the sites of the
relevant mechanoreceptors. In this paper, we present a two-scale approach that
involves a finite element model (FEM) at the macroscopic scale and a simple
bearing area model (BAM) that accounts for the measured roughness on the
papillary ridges. Both separate scales couple in an iterative way using the
concept of an equivalent air gap. We show that the electroadhesion-induced
changes in friction and contact area predicted by the proposed model are in
qualitative agreement with recent experimental studies. In a simple example, we
demonstrate that the model can readily be extended by a neural dynamics model
to investigate the tactile perception of electroadhesion.
