Method for eliciting tactile sensation using vibrating stimuli in tangential direction : Effect of frequency , amplitude and wavelength of vibrating stimuli on roughness perception

As a basis for eliciting tactile sensation evoked by sliding finger on surface of objects, the effects of frequency, amplitude, wavelength and waveform of vibrating stimuli on human’s roughness perception are investigated in this study. First, a prototype of tactile display device that can stimulate surface of finger in tangential direction is developed. By the psychophysical experiment with the device, it is confirmed that the sense of roughness mainly depends on amplitude and frequency of the wavy vibratory stimulus. Secondly, the effect of wavelength is investigated by use of finite element (FE) analysis. A FE model of fingertip that is precisely designed by the real human finger is used. In series of analyses, firstly dynamic contact analyses when finger slides on various uneven surfaces are performed and the strain energy histories at positions of mechanoreceptors that are mostly correlated to roughness perception are obtained. Next, wavy vibratory stimuli are applied on surface of the finger model with various wavelengths. Strain energy histories are obtained as well, and the results are compared with ones obtained by sliding on uneven surface. From comparison of results, it is clarified that there is a certain wavelength that can stimulate each kind of mechanoreceptors most effectively.