Development of artificial muscle having characteristics of human skeletal muscle

我们已经开发出由螺旋冷却形状记忆合金（SMA）丝制成的人造肌肉。为了减少金属疲劳，提高过渡力，采用扩散法制备了该SMA。该SMA对人工肌肉的转变温度为75ºC（Af点）。作为对SMA肌肉控制的可行性研究，我们建立了采用复杂的前臂和手部复制骨骼系统的假手动力学模型。机器人的万向关节被用作连接每个骨骼的关节。用一根不锈钢绳作为人造肌腱，将其固定在人体每块肌肉肌腱最初插入的骨头的指定点上。为了对每一块SMA肌肉施加电流，使用了我们开发的多通道功能电刺激（FES）系统。当前应用于SMA肌肉的模式是根据正常志愿者的手部运动记录的肌电图数据创建的。利用该系统在人工动态手模型中实现了圆柱形抓握和键握等手部运动。然后我们开发了一个肌肉单位通过一个地狱冷SMA钢丝。该丝直径0.1mm, D/ D =5。卷取次数为100。该肌肉单元在63cc时的过渡力（收缩力）为6kg /cm2。这一数值几乎与人类骨骼肌在最大收缩时的数值相同。用上述FES系统连接肌肉单元，制成兔肘关节的激动-拮抗剂系统。实验发现，该系统基本控制肘关节的屈伸。

We have developed artificial muscles made of helically colled shape memory alloy (SMA) wires. this SMA was made by diffusion method in order to reduce metal fatigue and to increase force of during transition. The transition temperature of this SMA for the artificial muscle was 75ﾟC(Af point). As feasible study of control of the SMA muscle, we made a dynamic model of the artificial hand where sophisticated duplicated skeleton system of the forarm and hand was used. Universal joints for robotics were used as joints for connecting each bone. A stainless steel rope was used as an artificial tendon and attached to the prescribed point of the bone where the tendon of each muscle is originally inserted in human. For applying current to each SMA muscle, a multichannel functional electrical stimulation (FES) system which we developed was used. Patterns of current application to SMA muscles were created from EMG data during hand motion recorded from normal volunteers. By using this system, hand motions such as cylindrical grasp and key grip were achieved in the artificial dynamic hand model.Then we have developed a muscle unit by a hellically colled SMA wire. Diameter of this wire was 0.1mm and D/d=5. Number of coiling was 100. Force of transition (contractile force) of this muscle unit was 6 kg/cm2 at 63ﾟC. This value was almost the same as that of human skeletal muscle during maximum contraction. An agonistantagonist system acting to the rabbit elbow joint with the above mentioned FES system was made by connecting the muscle units. It was found that flextion and extension of the elbow was basically controlled by this system.