Development of Artificial Finger Skin with Static Friction Sensation Imitating Human Finger Using PVDF Film

Th eg oal of our study is development of a sensor which has static friction sensation using paired pieces of PVDF film strips. In order to develop the sensor, we recall that the sensing function is supposed to be attained through incipient slip detection. First is designed the artificial finger whose characteristics are associated with those of a human finger with respect to the shape and a part of the sensing functions enabling the incipient slip detection: The finger skin has ridges on the surface in each of which a pair of artificial FAI receptors are embedded. The design process of two phases is also shown to secure useful information without any plastic deformation of the film strips. Design phase � 1i s to design the characteristics of a FAI receptor. As the transducer for the FAI receptors, we choose PVDF fil ms heets which have a dynamic stress rate characteristic. Design phase � 2i nvolves determination of the shape and size of the artificial finger skin, and the location of the transducers in a ridge. Signals from the transducers are analyzed concerning where the best position for each of the transducers is to utilize the information acquired from the transducers in the future process. We analyze the stress in the finger skin when incipient slip occurs at the surface. The experimental results reveal that the differential output voltage signal from a pair of artificial FAI receptors embedded in a ridge captures low-frequency vibration to generate a predictive signal which warns incipient slip of the ridge. The results also show, that high-frequency vibratory signal itself cannot be detected using the artificial FAI receptors and suggests a need of artificial FAII receptors in static friction sensory information processing.