Tactile sensing based on acoustic resonance tensor cell

We propose a new tactile sensing element, the acoustic resonant tensor cell. The structure is a spherical cavity in an elastic tactile sensor body with two fine ultrasound paths extended respectively to an ultrasonic transmitter and receiver which are placed at the bottom of the elastomer. The acoustic resonant frequency of the air in the cavity has an explicit relation with the principal stresses around it, which is easily detected by the ultrasonic transducers. The sensor is simple and elastic. The single structure obtains useful multi-dimensional tactile features. The principle of the device and experimental results are described.