Development of a sensor system for collecting tactile information

This paper presents the development of a sensor system for collecting tactile information. An active sensing system using the piezoelectric effect and the pyroelectric effect of a PVDF (Polyvinylidene fluoride) film is proposed. The active sensing is designed with human motions for tactile perception in mind. First, as the pretest, the distinction examination of six fabrics with different textures is carried out through human tactile perception. Next, the proposed sensor system is assembled. The sensor is composed of a PVDF film and a soft rubber. The surface of the sensor can be heated through temperature control. The sensor is attached on the tip of a robot finger driven by a piezoelectric bimorph strip and the root of the finger is mounted on a linear slider. Two kinds of active sensing are introduced. First, the heated sensor is contacted with an object and pyroelectric output signals are collected in order to obtain the information on tactile warmth. Next, the heated sensor is slid over the object and piezoelectric output signals are collected in order to obtain the information on feelings of vibration. Through the discussion about each sensing, three indexes representing features of the collected data are extracted and proposed as the sensor outputs for the evaluation of tactile sensation. The measurement using the sensor system is done on the samples used in the distinction examination. Comparison with the results shows that the sensor system extracts features on feelings of vibration and warmth.