Jorgovanovic Nikola, Dosen Strahinja, Djozic Damir J, Krajoski Goran, Farina Dario
Department for Systems, Signals and Control, Faculty of Technical Sciences, University of Novi Sad, Novi Sad, Serbia.
Department of Neurorehabilitation Engineering, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.
Comput Math Methods Med. 2014;2014:120357. doi: 10.1155/2014/120357. Epub 2014 Jan 2.
Closing the control loop by providing somatosensory feedback to the user of a prosthesis is a well-known, long standing challenge in the field of prosthetics. Various approaches have been investigated for feedback restoration, ranging from direct neural stimulation to noninvasive sensory substitution methods. Although there are many studies presenting closed-loop systems, only a few of them objectively evaluated the closed-loop performance, mostly using vibrotactile stimulation. Importantly, the conclusions about the utility of the feedback were partly contradictory. The goal of the current study was to systematically investigate the capability of human subjects to control grasping force in closed loop using electrotactile feedback. We have developed a realistic experimental setup for virtual grasping, which operated in real time, included a set of real life objects, as well as a graphical and dynamical model of the prosthesis. We have used the setup to test 10 healthy, able bodied subjects to investigate the role of training, feedback and feedforward control, robustness of the closed loop, and the ability of the human subjects to generalize the control to previously "unseen" objects. Overall, the outcomes of this study are very optimistic with regard to the benefits of feedback and reveal various, practically relevant, aspects of closed-loop control.
通过向假肢使用者提供体感反馈来闭合控制回路，是假肢领域一个广为人知且长期存在的挑战。人们已经研究了各种用于反馈恢复的方法，从直接神经刺激到非侵入性感觉替代方法。尽管有许多研究提出了闭环系统，但其中只有少数对闭环性能进行了客观评估，大多使用振动触觉刺激。重要的是，关于反馈效用的结论部分相互矛盾。当前研究的目标是系统地研究人类受试者使用电触觉反馈在闭环中控制抓握力的能力。我们开发了一个用于虚拟抓握的逼真实验装置，该装置实时运行，包括一组真实物体以及假肢的图形和动力学模型。我们使用该装置测试了10名健康的、身体健全的受试者，以研究训练、反馈和前馈控制的作用、闭环的鲁棒性以及人类受试者将控制推广到先前“未见”物体的能力。总体而言，这项研究的结果对于反馈的益处非常乐观，并揭示了闭环控制的各种实际相关方面。
