An Ultraprecision Aerostatic Guideway Controlled by Active Inherent Restrictors

提出了一种提高超精密定位系统中气体静压导轨性能的主动控制方法。所提出的方法采用了主动固有限制器（空气）来控制气动压力的导轨。作者发明的AIR是由一个带有通孔的压电致动器组成的，当致动器嵌入到要控制的导轨中时，通孔的一端足够小以起到夹持器的作用。六个AIR被整合到由空气静压导轨引导的工作台中;四个AIR用于补偿垂直位移，两个用于水平位移。微型计算机根据传感器检测到的工作台位移，改变压电作动器的长度，控制空气流量计的节流面积，补偿工作台的位移。在垂直方向和水平方向上，导轨的刚度可以无限大，工作台的直线度可以达到20 nm左右，而不出现气锤。还示出了AIR对金刚石调谐的效果;安装在由AIR控制的工作台上的铝合金被调谐，并且可以改善加工表面的粗糙度。

An active control method for improving the performance of an aerostatic guideway used in an ultraprecision positioning system is proposed. The proposed method employs an Active Inherent Restrictor (AIR) to control pneumatic pressure onthe guideway. The AIR invented by the authors consists of a piezoelectric actuator having a through hole, one end of which is small enough to function as an orificewhen the actuator is embedded in the guideway to be controlled. Six AIRs are incorporated into the table guided by the aerostatic guideway ; four AIRs for compensating the vertical displacement, and two for the horizontal displacement. According to the table displacements detected by sensors, amicro computer changes the length of the piezoelectric actuators for controlling the orifice area of the AIRs, and for compensating the displacements. In both vertical and horizontal directions, it was provedthat the stifness of the guideway can be infinite, and the straightness of motion of the table can beabout 20nm, while the pneumatic hammer did not occur. The effect of the AIR on diamond tuning is also shown ; an aluminum alloy mounted on the table controlled by the AIR was tuned, and the roughness on the machined surface can be improved.