Development of a wireless character-Input interface controlled by Laplacian electromyographic activity

我们结合一个小型的无线电极单元，一个肌电图（EMG）点击转换电路和字符输入软件，开发了一个无线字符输入接口。评价该接口的实验表明，通过收缩（a）脸颊的咬肌，（B）颈部的肌，（c）右前臂的胫前肌，或（d）右前臂的尺侧腕屈肌，可以稳定地输入所需的字符。我们还证实，平均积分肌电信号（IEMG）在字符输入任务中显着下降时，拉普拉斯肌电作为输入信号的接口，与传统的肌电时得到的IEMG相比，在7个8个科目。该接口可利用人体多个部位进行拉普拉斯肌电图测量，降低了这些部位肌肉继发性残疾的风险，适用于肢体残疾人。提出了一种通过在电极与被测者皮肤之间插入薄布来检测表面肌电图的方法。该方法是基于电容耦合，涉及电极，布，和皮肤。组装并评估了使用该方法的试验装置，以探索该方法的可行性。实验结果表明，用这种方法获得的表面肌电信号与传统方法获得的表面肌电信号具有可比性和同步性，但其幅度和信噪比有所降低。由于所提出的方法消除了由于传统的电极到皮肤的耦合的不适，它显示出用于人机接口，如人类自适应机电一体化（HAM）的承诺。

We have developed a wireless character-input interface by combining a compact wireless electrode unit, an electromyogram (EMG)-click converter circuit and character-input software. Experiments for evaluation of the interface showed that characters could be input stably as desired by contraction of (a) the masseter muscle of the cheek, (b) the trapezius muscle of the neck, (c) the anterior tibial muscle of the right crus, or (d) the flexor carpi ulnaris muscle of the right forearm. We also confirmed that the mean integrated EMG signal (IEMG) during the character-input task was significantly decreased in seven of eight subjects when the Laplacian EMG was used as the input signal of the interface, compared with the IEMG obtained when the conventional EMG was used. The developed interface appears applicable to persons with physical disabilities, because it can utilize many sites for the Laplacian EMG measurement, hence reducing the risk of secondary disability of the muscles at these sites.A method has been proposed for sensing the surface electromyogram (sEMG) through thin cloth inserted between the electrodes and the skin of the subject. The method is based on capacitive coupling involving the electrodes, the cloth, and the skin. A pilot device using this method was assembled and evaluated to explore the feasibility of this approach. The experimental results showed that the sEMG obtained in this way was comparable and synchronized with the conventionally obtained sEMG, although its amplitude and S/N were reduced. Since the proposed method eliminates discomfort due to conventional electrode-to-skin coupling, it shows promise for use in human-machine interfaces such as Human Adaptive Mechatronics (HAM).