DEVELOPMENT OF EMG CONTROLLED PROSTHETIC FOREARM USING ULTRASONICMOTORS

在开发一种人工装置时，例如。一个人用来克服残疾的假肢前臂，必须考虑以下几点：（1）它的操作应该简单和方便;（2）它的外观应该与实际肢体相似;（3）它的重量应该轻;（4）它的操作噪音应该可以忽略不计，或几乎可以忽略不计;研制了一种由小型超声波电机驱动的肌电控制的三自由度前臂假肢。它的重量不到700克，大小与成年人的前臂相同。使用直流电机的传统假肢产生运动噪声。因此，如何降低运动噪声是摆在我们面前亟待解决的问题之一。由于我们的假肢前臂使用超声波电机，它不会产生运动噪音。此外，截肢者还可以控制六种运动，e.前臂的旋前和旋后，腕关节的屈曲和伸展，以及抓握和手张开。截肢者与假肢前臂之间的接口是根据截肢者在截肢后仍然保留幻肢运动地图这一事实设计的。它能利用截肢者剩余肌肉的肌电信号从6种运动中识别出截肢者的预期运动，并产生控制假肢的指令信号，使截肢者能按自己的意愿操纵假肢，大大减轻了假肢的控制负荷。

In developing an artificial device, eg. a prosthetic forearm, which is used by a person to overcome disability, the following points have to be considered : (1) its manipulability should be simple and casy ; (2) its appearance should be physically similar to the actual limb ; (3) its weight should be light ; (4) its operating noise should be negligible, or nearly negligible ; and, (5) its power supply should be small and lightweight, In addition, the capability of the prosthctic device to mimic the response of the actual limb with respect to voluntary motor commands and to environmental loads should be addressed.We developed an EMG controlled prosthetic forearm with three degrees of freedom actuated by small size ultrasonic motors. Its weight is less than 700 g and the size is the same as the adult's forearm. The conventional prosthetic arm using DC motors produces a motion noise. So the reduction of the motion noise was one of the big problems to be soleved. Since our prosthetic forearm uses ultrasonic motors, it produces no motion noise. In addtion, the amputee can control six kinds of motions i. e. pronation and supnation of the forarm, flection and extension of the wrist, and grasping and hand-opening. The interface between the amputee and the prosthetic forearm was designed on the basis of the fact that the amputee still preserves the phantom limb motor map after amputation. It can discriminate the amputee's intended motion among six kinds of motions using the EMG signals from the remained muscles and also produce the command signals to control the prosthetic arm. Consequently, the amputee is able to manipulate the prosthetic arm as he intends and hes control load is relieved sharply.