High-power electrostatic levitation linear motor for ultra-clean and vacuum environment

本研究针对真空环境，研制出大功率静电直线悬浮马达。由于静电电机不产生磁场，因此适用于电子显微镜、电子束光刻机等真空环境下的电子束应用，本文首先研制了真空环境下的静电直线电机工作台，并利用该工作台研究了非悬浮静电电机在真空环境下的工作特性。在真空条件下，展开级产生的推力与正常情况下几乎相同。我们开发了一种新型的静电直线编码器，它被嵌入到静电电机中。利用研制的直线编码器，实现了真空条件下的定位控制。其次，研究了静电悬浮电机，将大功率静电电机技术与静电悬浮技术相结合。提出了悬浮电机的几种工作原理，并从理论上揭示了它们的特点。为了验证所提出的原则，我们已经开发了两个自由度的原型，它有一个自由度的推力方向和一个悬浮方向。研制的样机在真空条件下演示了悬浮驱动运动。滑块以200μm的间隙悬浮在定子下方，并以20 mm/s的速度沿推力方向移动。此外，我们进行了定位控制与保持悬浮状态。这些结果验证了所提出的静电悬浮电机的原则。

In this research, we have developed high-power electrostatic linear levitation motor for vacuum condition. Since electrostatic motor does not emit magnetic field it is suitable for EB applications, such as electron microscope and EB lithography system, which are some of the most important applications using vacuum condition.In the first step of the research, we have developed electrostatic linear motor stage specialized for vacuum use, with which characteristics of non-levitation electrostatic motor in vacuum condition was investigated. The developed stage generates almost the same thrust force in vacuum as in the normal condition. We have developed new electrostatic linear encoder which is embedded into the electrostatic motor. Using the developed linear encoder, we perform positioning control in vacuum condition.Next, we have studied electrostatic levitation motor, in which high-power electrostatic motor technology and electrostatic levitation technology are combined. We proposed several principles for levitation motor and revealed their characteristics theoretically. To verify the proposed principles, we have developed two-DOF prototype, which has one degree of freedom for thrust direction and one for levitating direction. The developed prototype demonstrated levitated driving motion in vacuum condition. The slider was levitated under the stator with a gap of 200μm and moved with a speed of 20mm/s in the thrust direction. Also, we performed positioning control with keeping levitated state. These results verify the proposed principles of electrostatic levitation motor.