Wearable skin vibration sensor using a PVDF film

This paper aims to develop a wearable tactile sensor for measuring skin vibrations using a polyvinylidene fluoride (PVDF) film, which is a polymer piezo material. The sensor is worn on the finger pad where is remote from contact fingertip and detects skin-propagated vibrations when fingertip touches an object. The proposed sensor allows users to touch with bare fingers and to conduct active touch. A transfer function from vibrations applied on the fingertip to the sensor output is expressed by using a finger model, a sensor model, and an electric model of the PVDF film. On the basis of the transfer function, frequency response of the sensor is measured and estimation of vibrations is tested. Furthermore, the sensor output is investigated for three materials with different textures. Results show the validity and availability of the sensor.