Development of an Embedded Myokinetic Prosthetic Hand Controller.

Francesco Clemente,Valerio Ianniciello,Marta Gherardini,Christian Cipriani

doi:10.3390/s19143137

Francesco Clemente, Valerio Ianniciello + Show 2 more

Open Access

https://doi.org/10.3390/s19143137

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Abstract

The quest for an intuitive and physiologically appropriate human machine interface for the control of dexterous prostheses is far from being completed. In the last decade, much effort has been dedicated to explore innovative control strategies based on the electrical signals generated by the muscles during contraction. In contrast, a novel approach, dubbed myokinetic interface, derives the control signals from the localization of multiple magnetic markers (MMs) directly implanted into the residual muscles of the amputee. Building on this idea, here we present an embedded system based on 32 magnetic field sensors and a real time computation platform. We demonstrate that the platform can simultaneously localize in real-time up to five MMs in an anatomically relevant workspace. The system proved highly linear (R2 = 0.99) and precise (1% repeatability), yet exhibiting short computation times (4 ms) and limited cross talk errors (10% the mean stroke of the magnets). Compared to a previous PC implementation, the system exhibited similar precision and accuracy, while being ~75% faster. These results proved for the first time the viability of using an embedded system for magnet localization. They also suggest that, by using an adequate number of sensors, it is possible to increase the number of simultaneously tracked MMs while introducing delays that are not perceivable by the human operator. This could allow to control more degrees of freedom than those controllable with current technologies.

Highlights

The loss of a limb, e.g., caused by vascular/infectious diseases or trauma, is an event that strongly affects the quality of life under several aspects
The tests with a single magnet using the 3D platform showed that the accuracy of the pose estimation has a non-monotonic trend with respect to the distance between the magnet and the Sensors 2019, 19, x FOR PEER REVIEW
The tests with a single magnet using the 3D platform showed that the accuracy of the pose estimation has a(Figure non-monotonic trend with the distance between the magnet sensors sensors plane

Summary

Introduction

The loss of a limb, e.g., caused by vascular/infectious diseases or trauma, is an event that strongly affects the quality of life under several aspects This event usually limits the person in performing working and daily living activities, having a strong impact on the social life. When independent agonist/antagonist muscle pairs are available each of these can be mapped to a unique function in the prosthesis, implementing the so called direct control [1]. The latter is the most intuitive and robust approach [2], albeit either not possible, due to the lack of accessible independent control sources with surface electrodes or inefficient [3] in the case of multiple functions/DoFs

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