握速可调式肌电假手的系统研究

针对假手无法根据使用者的意愿来控制其握合速度的问题，设计了一种握速可调的智能肌电假手。在该肌电假手系统中，电极引入的表面肌电信号，放大150倍后，在频域进行信号处理。经过阈值和等值计算，最终输出控制信号到驱动电路对假手的直流微电机进行控制。10名受试者参加了抓握试验，每人重复5次，记录输入肌电信号强度为500、1 000、1 500 mV时的输出电流、输出电压和握力等值，并拟合假手输出电压、输出电流、握力与输入肌电信号大小的曲线。拟合结果表明，假手速度与输出电压成正相关，在带有负载且不过载时，握力随着输出电流增大而增大。本假手系统具有稳定性，同时和假手握速可通过检测到的肌电信号强弱进行调节，提高了假手的灵活性。

A Control System for the Myoelectric Prosthetic Hand with Adjustable Grip Speed

In this study,an intelligent electromyography prosthetic hand with adjustable grip speed was developed. In this system, the surface electromyography signals (sEMG) acquierd by surface electrodes was preliminarily amplified about 150 times and processed using frequency domain analysis method. Through threshold and the equivalent calculation, the control signal was input into the driving circuit of DC micro motor for the prosthetic hand. 10 volunteers attended the gripping experiments and each experiment was repeated five times. Under the condition that the amplitudes of sEMG were 500, 1 000and 1 500 mV, the mean and standard deviation of the signals, including output voltage, output current and grip strength, were recorded. The relations among output voltage, output current, grip strength and sEMG ampltude were obtained by fitting analysis. The results indicated that the prosthetic hand speed positively corelated with the output voltage. with load but not overload， grip strength increased with the increasing output current. The results proved the stability of the developed system. And the grasping speed of the system can be adjusted as well. The system with adjustable grip speed improves the flexibility of the prosthet hand.