Passive wireless sensing element for sensitive skin

In this paper, we propose a method to realize flexible sensor skins integrated onto robot surfaces. By implanting wireless sensing elements in an elastic body, we obtain an elastic and tough sensitive skin which allows to be shaped freely. The element is a passive resonator chip whose resonant frequency reflects the stress around the chip. The resonant frequency is read out by a ground coil located at the bottom of the skin. The chip is simply composed of three functional parts, a coil for receiving and transmitting electrical power with wireless coupling, capacitance sensitive to stress, and ceramic resonator to provide high-Q resonance. The high quality factor brought by ceramic resonator enables us to distinguish a large number of chips, and to sense the stress with high accuracy. The structure, the method of wireless signal detection, and basic experiments of tactile sensing are presented