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Practical utility of a wearable skin vibration sensor using a PVDF film

We have developed a wearable skin vibration sensor using a polyvinylidene fluoride (PVDF) film. The sensor is attached to the finger pad between distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints and users can touch an object with the bare finger. It detects the skin-propagated vibration. In previous reports, we demonstrated that the sensor output well describes tactile information. This paper investigates the practical utility of the sensor. First, an experiment on tangential vibration is conducted and results show that the sensor can respond to the tangential vibration given to the fingertip at a similar level as the normal vibration. Then, the influence of wearing tension and contact force on the sensor output is investigated. Experimental results show that the wearing tension does not largely influence the sensor output within natural tensions, and that the intensity and the peak frequency in the gain of the sensor output tend to increase with the increase of the contact force. In particular, the intensity of the sensor output is different between contact forces of 0.25 and 0.5 N.