Impact Resilience Measurement of Elastic Materials by using Active Tactile Sensor

This paper proposes an active tactile sensor driven by using piezo-electrical actuator. It consists of a silicon diaphragm having piezoresistive strain sensors for measuring displacement of the diaphragm, and a piezoelectric actuator for driving the sensing element. The proposed active tactile sensor has an advantage in that it can detect the multiple physical values, elasticity and impact resilience of a contact object, by analyzing the obtained step-response waveform. We fabricated the sensor element by using micro-electro-mechanical-systems (MEMS) technologies, and assembled it with a commercially available piezoelectric actuator in hybrid manners to produce the active tactile sensor. The sensor was 15 mm times 15 mm times 20 mm. Six different rubbers of different hardness ranging from A30 to A70 in Shore A, was used to evaluate the elasticity detection function of the sensor, and we confirmed that the output increased linearly with the increase in the rubber hardness (elasticity). We also evaluated two different rubber materials, urethane and damping rubbers, which had different values of impact resilience, and found that step responses of the sensor output were quite different between two (the damping rubber showed overshooting phenomena at the rise). We therefore concluded that the proposed sensor is capable of detecting two values, elasticity and impact resilience, of a contact object