Embedded Electrotactile Feedback System for Hand Prostheses using Matrix Electrode and Electronic Skin

As the technology moves towards more human-like bionic limbs it is necessary to develop a feedback system that provides active touch feedback to a user of a prosthetic hand. Most of the contemporary sensory substitution methods comprise simple position and force sensors combined with few discrete stimulation units,and hence they are characterized with a limited information bandwidth. The present study describes a novel system for tactile feedback integrating advanced distributed sensing (electronic skin) and stimulation (matrix electrodes). The system comprises a flexible sensing array (16 sensors) integrated on the index finger of a Michelangelo prosthetic hand mockup,embedded interface electronics and multichannel stimulator connected to a flexible matrix electrode (24 pads). To demonstrate the feasibility,the system was tested in six able-bodied subjects who were asked to recognize static patterns (contact position) with two different spatial resolutions and dynamic movement patterns (i.e.,sliding along and/or across the finger) presented on the electronic skin. The experiments demonstrated that the system successfully translated the mechanical interaction into electrotactile profiles,which the subjects could recognize with good performance (Static patterns: 91 4% and 5810% for low and high spatial resolution,respectively,and 943% for sliding touch). These results demonstrate that the developed system is an important step towards a new generation of tactile feedback interfaces that can provide high-bandwidth interfacing between the user and his/her bionic limb. Such systems would allow mimicking spatially distributed natural feedback,thereby facilitating the control and embodiment of the artificial device into the user body scheme.