Development of a Multi-Layered Electrostatic Film Actuator for an Artificial Muscle

本研究的目的是借由堆叠薄膜状的静电驱动器，发展出一种具有大作用力密度的肌肉状弹性驱动器--静电人工肌肉。静电人工肌肉是由研究人员专门为人工肌肉新开发的感应电荷膜致动器构建的。感应充电膜致动器由具有大量条形电极的定子膜和涂覆有高电阻层的滑动膜组成。本研究针对薄膜驱动器的材料、设计、制作与控制等关键技术进行研究，并开发出人工肌肉原型。本项目取得了以下成果：1.制作了两个感应电荷薄膜驱动器样机。一个具有420微米间距的电极，另一个具有120微米间距的电极。两个执行机构均成功运行。2.采用数值电场分析方法研究了感应电荷驱动器的特性。结果发现，定子上的电极与滑块上的电阻层之间的距离的最佳值为电极间距的1/5。3.利用420 μ m间距和100 μ m间距的薄膜驱动器构建了两个静电人工肌肉原型。通过具有较小节距的电极的人造肌肉获得更好的性能。其力密度和功率密度分别为35 N/kg和1 W/kg。这种力密度与传统的电磁致动器相当。4.提出了微步驱动方法。在常规方法驱动的感应电荷致动器中，在一个驱动序列中滑块的位移等于电极间距。微步驱动将分辨率降低到小于电极间距的1/40。

The goal of the research is to develop an electrostatic artificial muscle, a muscle-like flexible actuator with large force density, by stacking thin, film-shaped electrostatic actuators. The electrostatic artificial muscle is constructed from induction charge film actuators newly developed by the investigators specifically for the artificial muscle. The induction charge film actuator consists of a stator film having a large number of striped electrodes and a slider film coated with a high-resistor layer. In this research project, key technologies for the film actuator such as material, design, fabrication, and control techniques are investigated and prototypes of artificial muscle are developed. The following results are obtained in the project.1. Two prototypes of the induction charge film actuator are fabricated. One has 420mum-pitched electrodes and the other has 120mum-pitched electrodes. Both actuators are successfully operated.2. Characteristic of the induction charge actuator is investigated by means of numerical electric field analysis. As a result, the optimum value for the distance between electrodes on the stator and the resistor layer on the slider is found to be 1/5 of the electrode pitch.3. Two prototypes of the electrostatic artificial muscle are constructed using the film actuators with 420mum-pitched and 100mum-pitched electrodes. Better performance is attained by the artificial muscle with electrodes of the smaller pitch. Its force density and power density are 35N/kg and 1W/kg respectively. This force density is comparable to conventional electromagnetic actuators.4. Micro step driving methods are developed. In the induction charge actuator driven by the normal method, the displacement of the slider in one sequence of drive equals to the electrode pitch. The micro step drive reduces the resolution to be less than 1/40 of the electrode pitch.