A System for Electrotactile Feedback Using Electronic Skin and Flexible Matrix Electrodes: Experimental Evaluation

Abstract

Abstract-Myoelectric prostheses are successfully controlled using muscle electrical activity, thereby restoring lost motor functions. However, the somatosensory feedback from the prosthesis to the user is still missing. The sensory substitution methods described in the literature comprise mostly simple position and force sensors combined with discrete stimulation units. The present study describes a novel system for sophisticated electrotactile feedback integrating advanced distributed sensing (electronic skin) and stimulation (matrix electrodes). The system was tested in eight healthy subjects who were asked to recognize the shape, trajectory and direction of a set of dynamic movement patterns (single lines, geometrical objects, letters) presented on the electronic skin. The experiments demonstrated that the system successfully translated the mechanical interaction into the moving electrotactile profiles, which the subjects could recognize with a good performance (shape recognition: 86±8% lines, 73±13% geometries, 72±12% letters). In particular, the subjects could identify the movement direction with a high confidence. These results are in accordance with previous studies investigating the recognition of moving stimuli in human subjects. This is an important development towards closed-loop prostheses providing comprehensive and sophisticated tactile feedback to the user, facilitating the control and the embodiment of the artificial device into the user body scheme.

Robotic interfaces for cognitive psychology and embodiment research: A research roadmap

“…Due to these reasons, high-density surface electromyography (HD-sEMG) as well as tactile sensing have already been investigated out in academic environments (Ison, Vujaklija, Whitsell, Farina, & Artemiadis, 2016;Radmand, Scheme, & Englehart, 2016;Nissler, Connan, Nowak, & Castellini, 2017). In addition, electrocutaneous (Franceschi et al, 2017) feedback with high spatial resolution and biomimetic coding techniques for natural feedback are (Valle et al, 2018) being explored. What is missing so far, we believe, is a tighter integration of the approaches serving the efferent and afferent channels, which might lead to unprecedented results.…”

Soft human–machine interfaces: design, sensing and stimulation

“…Integrating distributed sensing (E-skin) and stimulation (matrix electrodes), an electrotactile feedback system was proposed in Ref. [160] that helped user subjected to recognize dynamic movement patterns. It embodies closed-loop artificial devices into the user body scheme.…”

Ionic Gels and Their Applications in Stretchable Electronics

“…The rapid advancement of stretchable electronics facilitates the integration of stretchable devices into complex systems, such as electronic skins (E‐skin), wearable electronics, soft robotics, and implantable devices. In particular, E‐skin, which replicates the sensory capabilities and mechanical stretchability of human skin, has attracted great academic interest in the last decade .…”