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.

Human-friendly robots of new generation will require sensor skin that is soft and covering the whole body. But it would be very difficult to fabricate it with the traditional technology, because placement and wiring of a vast amount of sensor elements on the 3-dimensionally configured robot surface is laborious. We propose a novel method to fabricate such a sensor skin. The skin contains sensor chips which receive the electrical power and transmit the tactile signal without wires. The skin is configured in an arbitrary shape easily, and it is elastic and tough because each sensing element does not need any fragile wires. The principle and the experimental results are described.