Development of the myoelectric prosthetic hand with sensory feedback system using electrotactile stimulation

本研究的目的是开发高可靠性便携式肌电假手及其触觉电刺激的感觉反馈系统。(1)假手控制电路在原有电路的基础上，开发了便携式低功耗假手控制电路。(2)感觉反馈系统作为肌电假手的感觉反馈系统，开发了一种新型人工触觉系统。该系统传输几个单词（口头信息），其中两个能够产生明显运动的通道电触觉刺激应用于前臂。提供了关于抓取物体状态和手指角度的口头信息。为了证明该系统的有效性，我们对一个健康的被试进行了抓握实验。实验表明，受试者在有系统的情况下比没有系统的情况下能更短地掌握物体。(3)人工指尖为了研制用于肌电假手的柔软人工指尖，对指尖的静态力学性能进行了研究。研究了皮肤和组织的应变与应力之间的关系。受试者为4名正常男性和1名正常女性。结果表明，应力随应变的增加呈非线性增加。在此基础上，用两种聚氨酯树脂制备了人工指尖。结果表明，用人工指尖固定的手可以稳定地握住玻璃。

The purpose of this research was to development of the high reliability and portable myoelectric prosthetic hand and its sensory feedback system using electrotactile stimulation.(1) Control circuits for prosthetic handThe portable and low powered electric circuit for prosthetic hand was developed based on the previous version of the circuits.(2) Sensory feedback systemThe novel artificial tactile system was developed as sensory feedback system for the myoelectric prosthetic hand. This system was transmitted a few words (verbal information) in which two channel electrotactile stimulation capable of generating apparent movements was applied to the forearm. The verbal information was provided regarding the state of grasping objects and the finger angle. In order to show the usefulness of this system, we executed grasping experiments with one healthy subject. It was shown that the subject could grasp the object for shorter periods with this system than without system.(3) Artificial fingertipsThe static mechanical properties of the fingertips were investigated in order to develop the soft artificial fingertips for the myoelectric prosthetic hand. The relationships between the strain and stress of the skin and tissue were investigated as the mechanical properties. The subjects were four normal men and one normal woman. It was shown that the stress was increased non-linearly with increasing of the strain. The artificial fingertips based on the obtained properties were made from two kinds of urethane resin. It was shown that the glass could be grasped stably with the hand attached the artificial fingertips.