Vertically stacked capacitive tactile sensor with more than quadrupled spatial resolution enhancement from planar arrangement

In this study, the spatial resolution of a capacitive tactile sensor was enhanced more than fourfold without sacrificing the sensitivity and functionality of the sensor, compared with conventional sensors with a planar capacitance arrangement. Through the vertical stacking of two capacitors with a shared electrode, the spatial resolution was at least doubled in both x- and y-directions, and the overall density of the sensing unit was more than quadrupled for arbitrary application sizes. In addition to shear angle detection, sensing demonstrations were performed on the normal and shear forces with theoretical designs, numerical evaluations, and empirical examinations. The proposed capacitive tactile sensor has a simplified manufacturing process and an efficient detection method realized by the shared electrode, in addition to the enhanced spatial resolution. This novel design can be applied to automatic robots for grasping tiny objects because the spatial resolution can be enhanced by simply replacing the four capacitors in a conventional planar arrangement with two vertically stacked capacitors as a universal solution.