Electromechanical behavior of soft porous capacitive sensors

Soft tactile sensors are core components for enabling soft robots perception. Their performance can be tuned shaping the electromechanical characteristics of their materials and structure at the microscale. In this work, the behavior of soft capacitive pressure sensors, based on porous dielectric material, is studied by means of 2D FEM simulations. In particular, from the mechanical point of view, it is shown how the apparent Young's modulus decreases with increasing porosity. Then, the variation of initial capacitance and the output characteristics with different level of porosity is discussed, showing that the sensitivity in the simulated structure can improve remarkably, with a tenfold increase for porosity around 30%. Deviations from empirical or simplified analytical expression found in the literature are shown and discussed.