Artificial SA-I and RA-I afferents for tactile sensing of ridges and gratings

Nicholas Pestell, Thom Griffith, Nathan F Lepora

Research output: Contribution to journalArticle (Academic Journal)peer-review

15 Citations (Scopus)


For robot touch to reach the capabilities of human touch, artificial tactile sensors may require transduction principles like those of natural tactile afferents. Here we propose that a biomimetic tactile sensor (the TacTip) could provide suitable artificial analogues of the tactile skin dynamics, afferent responses and population encoding. Our three-dimensionally printed sensor skin is based on the physiology of the dermal-epidermal interface with an underlying mesh of biomimetic intermediate ridges and dermal papillae, comprising inner pins tipped with markers. Slowly adapting SA-I activity is modelled by marker displacements and rapidly adapting RA-I activity by marker speeds. We test the biological plausibility of these artificial population codes with three classic experiments used for natural touch: (1a) responses to normal pressure to test adaptation of single afferents and spatial modulation across the population; (1b) responses to bars, edges and gratings to compare with measurements from monkey primary afferents; and (2) discrimination of grating orientation to compare with human perceptual performance. Our results show a match between artificial and natural touch at single afferent, population and perceptual levels. As expected, natural skin is more sensitive, which raises a challenge to fabricate a biomimetic fingertip that demonstrates human sensitivity using the transduction principles of human touch.

Original languageEnglish
Article number20210822
Pages (from-to)20210822
JournalJournal of the Royal Society Interface
Issue number189
Publication statusPublished - 1 Apr 2022

Bibliographical note

Funding Information:
This research was funded by a Leverhulme Research Leadership Award on ‘A biomimetic forebrain for robot touch’ (RL-2016-39) and an EPSRC DTP PhD Scholarship for N.P. Acknowledgements

Publisher Copyright:
© 2022 The Author(s) Published by the Royal Society. All rights reserved.

Structured keywords

  • Engineering Mathematics Research Group


  • Biomimetics
  • Fingers/physiology
  • Mechanoreceptors/physiology
  • Touch/physiology
  • Touch Perception


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