A Multifunctional Tactile Sensor Based on PVDF Films for Identification of Materials

A new multifunctional tactile sensor based on polyvinylidene fluoride (PVDF) films has been developed for material identification. In the sensor, the voltages induced by the electrostatic and piezoelectric effects (contact voltages) at the contact between the sensor and a sample are measured by a PVDF film. The voltage induced by the electrostatic effect is measured by the front electrode of a PVDF film when the back electrode is grounded. The voltage induced by the piezoelectric effect is measured by the back electrode of the PVDF film when the front electrode is grounded. In addition, the electrical properties (capacitance) of the sample are measured by electrodes on the front of two PVDF films. The multifunctional tactile sensor can therefore be used to simultaneously determine several parameters of a sample material. The sensor was used to identify ten material samples including acrylic, glass, polytetrafluoroethylene (PTFE), aluminum, and three kinds of both sponge and gel. The contact voltages of the sample materials were measured, and the hardness of each sample was determined. The results suggest that the sensor shows promise for tactile sensing applications although there are still some problems that require addressing.