Development of Biomimetic Prosthetic Hand

本研究的目的是研制一种由肌电图控制的仿生假手。这只手模仿了人类神经肌肉控制系统的动态特性，并具有辅助的感觉反馈系统。我们开发了一种便携式仿生手控制系统。该系统由肌电信号处理单元、直流电机数字伺服系统和两组蓄电池组成。研制了一种用于仿生手的新型柔性手套。该橡胶手套由高度脱蛋白的天然橡胶制成，具有低变形抗力，在很大程度上不干扰假手的运动。我们开发了两种类型的补充感觉反馈系统，通过振动刺激将施加在假体手指上的力的信息传递给使用者。在一个系统中，采用了最佳振动频率（250Hz）。在这个频率下，使用者能感觉到的刺激幅度最小。其他系统利用次声振动触觉刺激。在一个正常受试者用假手抓取柔软物体的实验中，这些系统的效用得到了证明。我们开发了一种肌电手模拟器，使截肢者可以尝试操作肌电手，并确定适当的控制系统参数。在该模拟器中，假手的运动和使用者上肢的姿势用三维计算机图形实时显示。肌电控制实验表明，该模拟器能够控制假手的手指角度，实现虚拟抓取。

The purpose of this study was to develop a biomimetic prosthetic hand controlled by electromyogram. This hand mimicked dynamic properties of human neuromuscular control system and had a supplementary sensory feedback system.We developed a portable control system of the biomimetic hand. This system consisted of processing units of EMG signals, a digital servo system of DC motor and two sets of battery. A new type of flexible glove for the biomimetic hand was developed. This rubber glove was made of highly deproteinized natural rubber with low deformation resistance and did not disturb a motion of the prosthetic hand to a large extent.We developed two types of supplementary sensory feedback systems, which transmitted information of the force applied to the finger of the prosthesis to its user with vibotactile stimuli. In one system, optimum frequency (250Hz) of vibration was utilized. At this frequency, the amplitude of stimuli that the user could sense was smallest. Other system utilized infrasonic vibrotactile stimuli. Utility of these systems were shown by the experiment where a normal subject was grasping soft objects with the prosthetic hand.We developed a simulator of myoelectric hand with which amputees could try to operate the myoelectric hand and to decide appropriate parameters of the control system. In this simulator, the motion of the prosthetic hand and posture of user's upper extremity were displayd with real-time 3D computer graphics. Myoelectric control experiments showed that the user was able to control finger-angles of prosthetic hand and to grasp the object virtually with this simulator.