Clemente Francesco, Ianniciello Valerio, Gherardini Marta, Cipriani Christian
The Biorobotics Institute, Scuola Superiore Sant'Anna, 56127 Pisa, Italy.
Department of Excellence in Robotics & AI, Scuola Superiore Sant'Anna, 56127 Pisa, Italy.
Sensors (Basel). 2019 Jul 17;19(14):3137. doi: 10.3390/s19143137.
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 ( = 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.
寻求一种直观且生理上合适的人机界面来控制灵巧假肢的工作远未完成。在过去十年中，人们投入了大量精力来探索基于肌肉收缩时产生的电信号的创新控制策略。相比之下，一种名为肌动接口的新方法是从直接植入截肢者残留肌肉中的多个磁性标记（MM）的定位中获取控制信号。基于这一理念，我们在此展示一种基于32个磁场传感器和实时计算平台的嵌入式系统。我们证明该平台能够在解剖学相关工作空间中实时同时定位多达五个MM。该系统具有高度线性（ = 0.99）和精确性（1%重复性），同时计算时间短（4毫秒）且串扰误差有限（为磁体平均行程的10%）。与之前的个人计算机实现方式相比，该系统具有相似的精度和准确性，同时速度快约75%。这些结果首次证明了使用嵌入式系统进行磁体定位的可行性。它们还表明，通过使用足够数量的传感器，可以增加同时跟踪的MM数量，同时引入人类操作员无法察觉的延迟。这可能允许控制比当前技术可控制的更多自由度。
