Soft dielectrics for capacitive sensing in robot skins: Performance of different elastomer types

In a capacitive tactile sensor the dielectric layer plays an important role: both its electrical and mechan-ical properties affect the capacitance variation and the sensor response in terms of sensitivity, since thedeformation ability of the dielectric layer allows for the detection of small pressures, and spatial reso-lution, since the dielectric layer acts as a low-pass spatial filter decreasing the spatial resolution. In thiswork we comparatively evaluate the effect of different elastomers on the performance of a capacitivesensor designed to cover large areas of a robot body. In particular, we compare the sensitivity, the spatialresolution and the durability of the sensor using foams, bulk elastomers and high permittivity composites.