Wireless tactile sensing element using stress-sensitive resonator

Robots that work with humans require a soft sensor skin to cover the entire body. In this paper, we propose a new method to realize such a skin. By im planting wireless sensing elements in an elastic body, we obtain an elastic and tough sensor skin which is able 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 th e bottom of the skin, The chip is simply composed of three functional parts , a coil for receiving and transmitting electrical power with wireless coup ling, capacitance sensitive to stress, and ceramic resonator to provide hig h-e resonance, The high quality factor brought by the ceramic resonator ena bles us to distinguish a large number of chips, and to sense the stress wit h high accuracy. The structure, the method of wireless signal detection, an d basic experiments of tactile sensing are presented.