Development of artificial skin surface ridges with vibrotactile sensing elements for incipient slip detection

Deals with the development of artificial skin surface ridges for incipient slip detection in pursuit of elucidating the mechanism of static friction sensing. We have two design phases of developing artificial skin with vibrotactile sensing elements incorporated in the skin surface ridges, before we can reach a solution to the optimized shape, size and functions. Phase #1 is to examine dynamic characteristics of the sensing elements following the results from circuit simulation analysis. Phase #2 is to design shapes and sizes of the artificial skin using FE analysis. In the study, we select PVDF film as the transducer of the sensing elements, and verify that the PVDF film transducer connected with an amplifier displayed unique characteristics of stress-rate and stress-jerk sensing functions. The characteristics are separated by a cut-off frequency of approximately 1.2 kHz in the frequency domain. We show by both analyses and experiments that the signal obtained from the transducer circuit with the above cut-off frequency characteristics convey useful information to predict a gross slip through detection of incipient slip.