Tecnalia Serbia Ltd., Belgrade, Serbia.
University of Belgrade - School of Electrical Engineering, Belgrade, Serbia.
Artif Organs. 2022 Oct;46(10):2034-2043. doi: 10.1111/aor.14339. Epub 2022 Jun 28.
Providing real-time haptic feedback is an important, but still not sufficiently explored aspect of the use of supernumerary robotic limbs (SRLs). We present a multi-pad electrode for conveying multi-modal proprioceptive and sensory information from SRL to the user's thigh and propose a method for stimuli calibration.
Within two pilot tests, we investigated return electrode configuration and active electrode discrimination in three healthy subjects to select the appropriate electrode pad topology. Based on the obtained results and anthropometric data from the literature, the electrode was designed to have three branches of 10 pads and two additional pads that can be displaced over/under the electrode branches. The electrode was designed to be connected to the stimulator that allows full multiplexing so that specific branches can serve as a common return electrode. To define the procedure for application of this system, the sensation, localization, and discomfort thresholds applicable for the novel electrode were determined and analyzed in 10 subjects.
The results showed no overlaps between the three thresholds for individual pads, with significantly different average values, suggesting that the selected electrode positioning and design provide a good active range of useful current amplitude. The results of the subsequent analysis suggested that the stimuli intensity level of 200% of the sensation threshold is the most probable value of the localization threshold. Furthermore, this level ensures a low chance (i.e., 0.7%) of reaching the discomfort.
We believe that envisioned electrotactile system could serve as a high bandwidth feedback channel that can be easily set up to provide proprioceptive and sensory feedback from supernumerary limbs.
提供实时触觉反馈是使用冗余机器人肢体（SRL）的一个重要但仍未充分探索的方面。我们提出了一种多垫电极，用于将多模式本体感觉和感觉信息从 SRL 传递到用户的大腿，并提出了一种刺激校准方法。
在两项初步测试中，我们研究了三个健康受试者的返回电极配置和主动电极辨别，以选择合适的电极垫拓扑结构。基于获得的结果和文献中的人体测量数据，设计了具有三个 10 个垫分支和两个额外垫的电极，这些垫可以在电极分支上/下移动。电极设计为连接到允许全复用的刺激器，以便特定分支可以用作公共返回电极。为了定义应用此系统的程序，在 10 个受试者中确定并分析了适用于新型电极的感觉、定位和不适阈值。
结果表明，单个垫的三个阈值之间没有重叠，平均值差异显著，表明所选的电极定位和设计提供了有用电流幅度的良好主动范围。随后的分析结果表明，刺激强度为感觉阈值的 200%是定位阈值最可能的值。此外，此级别可确保不适的可能性（即 0.7%）较低。
我们相信，设想中的电触觉系统可以作为一个高带宽反馈通道，可以轻松设置以提供冗余肢体的本体感觉和感觉反馈。
