Two Degrees of Freedom of EMG-Based Proportional Control in a Hand-Wrist Prosthes

摘要：每年约有18，496人经历上肢截肢 在美国，大多数截肢都是经桡动脉或更远端的。现有商业 假体装置仅允许这样的用户一次控制一个装置（例如，之间进行选择 手致动和手腕致动），通常经由基于EMG的输入。然后用户切换 设备之间的顺序。据悉，直接控制两个关节的是错误的--两个 比例控制的自由度-是最大的理想假体改进 这些用户的描述。 最近的几项研究进展表明， 7-128个电极与手指或手指中的2-5个自由度之间的关联 手腕。然而，高通道电极系统的使用在近期内将是不实际的。 在大多数商业系统中。其他研究系统采用多功能模式 识别，以便截肢者可以在有限的一组预编程多关节 动作虽然有用，但所有功能仍然仅由一个自由度组成。 一次移动。但是，如果两个自由度的独立，比例控制可以 由少至四个常规电极提供，现有的假体硬件可以 立即使用该技术。这将大大改善功能。 因此，我们提出了一个基于EMG的假肢控制器的演示， 在前臂上应用四个传统的电极，并提供两个独立的，成比例的 自由度。我们建议通过对10个肌电部队任务的技术演示 健康受试者和5例单侧经桡截肢者，其中EMG与关节相关 扭矩/力。对于截肢者，在力镜像期间，将从健全肢体测量力 任务因为我们提出的方法的四个电极的最佳位置不是 先验已知，我们将在实验数据收集期间应用多达16个电极，然后 在离线处理期间减少到四个电极。对于两个自由度，我们 将研究收缩的三个维度：腕关节屈曲-伸展、尺桡骨偏斜 和旋前旋后。离线分析将确定收缩的哪两个维度 为假体中的两个自由度提供最可分离的控制信号。

SUMMARY: Upper limb amputation is experienced by approximately 18,496 persons annually in the U.S., with most of these amputations transradial or more distal. Existing commercial prosthesis devices only allow such users to control one device at a time (e.g., choose between hand actuation and wrist actuation), commonly via EMG-based inputs. Users then switch between devices sequentially. It is reported that direct control of two joints simultaneously-two degrees of freedom of proportional control-is the greatest desired prosthesis improvement described by these users. Several recent research advancements have demonstrated independent, proportional association between 7-128 electrodes and 2-5 degrees of freedom in the fingers or in the hand-wrist. However, the use of high-channel electrode systems will not be practical in the near future in most commercial systems. Other research systems apply multifunction pattern recognition so that amputees can select between a limited set of pre-programmed multi-joint movements. While useful, all functions are still only comprised of one degree of freedom of movement at a time. But, if two degrees of freedom of independent, proportional control could be provided by as few as four conventional electrodes, existing prosthesis hardware could immediately implement the technique. Substantial improvement in function would result. Therefore, we propose the demonstration of an EMG-based prosthesis controller that applies four conventional electrodes on the forearm and provides two independent, proportional degrees of freedom. We propose demonstration of the technique via an EMG-force task on ten able-bodied subjects and five unilateral transradial amputees in which EMG is related to joint torque/force. For amputees, force will be measured from the sound limb during a force mirroring task. Because the best locations of the four electrodes for our proposed approach are not known a priori, we will apply up to 16 electrodes during experimental data collection and then reduce down to four electrodes during offline processing. For the two degrees of freedom, we will investigate three dimensions of contraction: wrist flexion-extension, ulnar-radial deviation and pronation-supination. Offline analysis will determine which two dimensions of contraction provide the most separable control signals for two degrees of freedom in a prosthesis.