Artificial SA-I and RA-I Afferentsfor Tactile Sensing of Ridges and Gratings

For robot touch to converge with the human sense of touch, artificial transduction should involve biologically-plausible population codes analogous to those of natural afferents. Using a biomimetic tactile sensor with 3d-printed skin based on the dermal-epidermal boundary, we propose two novel feature sets to mimic slowly-adapting SA-I and rapidly-adapting RA-I typeI tactile mechanoreceptor function. Their plausibility is tested with three classic experiments from the study of natural touch: impingement on a flat plate to probe adaptation and spatial modulation; stimulation by spatially-complex ridged stimuli to probe single afferent responses; and perception of grating orientation to probe the population response. Our results show a match between artificial and natural afferent responses in their sensitivity to edges and gaps; likewise, the human and robot psychometric functions match for grating orientation. These findings are of benefit to robot manipulation, prosthetics and the neurophysiology of touch. 1 ar X iv :2 10 7. 02 08 4v 2 [ cs .R O ] 1 6 Ju l 2 02 1

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