Multi-channel Electro-tactile Feedback System for a Prosthetic Hand

Abstract

Amputees with prosthetic hands often have difficulty holding and manipulating objects due to the absence of the sense of touch. This is especially true with tasks that require some degree of skill and tactile feedback to perform. To provide prosthetic hands with touch sensing and tactile feedback, researchers have been experimenting with various types of force and/or tactile sensors together with various methods for delivering the tactile information to the brain. Although some success has been achieved recently with force sensors and implanted electrodes, these systems are expensive, surgically invasive and can represent an infection risk where cables are attached to nerves through the skin. Also, non-invasive tactile feedback methods involving temperature, vibrations or electro-mechanical force feedbacks, can be somewhat awkward and ineffective due to being cumbersome or unable to deliver appropriate sensations. To address some of these issues we have developed an electro-tactile feedback system for prosthetic hands. Our system is comprised of force sensors that can be placed almost anywhere on a prosthetic hand, and TENS electrodes that can be placed on the wearer’s arm. Our system is inexpensive, multi-channel and easily fitted to existing prosthetic hands. Experimental results are provided that show how this form of tactile feedback can enable a user to feel various objects touched or gripped with a robotic humanoid hand.