直线电机气浮精密定位平台设计与控制

Design and control of air bearing precision positioning stage driven by linear motors

为了掌握光刻机工件台的设计和控制技术,建立了双边直线电机驱动的H型气浮精密定位平台,对该精密定位系统的气浮导轨设计方法、双边直线电机同步运动控制等关键技术进行了研究.利用有限元计算方法分析设计了气浮导轨,采用预加载技术提高气浮导轨的承载能力和刚度.实验结果表明:气浮导轨具有较高的承载能力和刚度,X和Y导轨的竖直方向静刚度为276.9N/μm和333.3N/μm.H型工作台的双边直线电机需要高精度的同步运动控制,传统的串、并联同步控制不能满足精度要求,设计了基于同步速度偏差的改进型并联结构同步控制器,采用模糊控制实现PID参数的自适应整定.实验表明:采用改进的控制器将速度同步精度提高了3倍多,适合于具有强机械耦合的多电机同步运动控制.H直线电机气浮定位平台具有承载能力强(40 kg)、精度高(<2μm)的优点,可用于精密工程领域.

In order to master the design and control techniques of the workpiece table in photoetching machine, an H-type air bearing precise positioning stage driven by dual linear motors was established. Some key techniques, including design method of air bearing slider and synchronic-motion control of dual linear motors, were studied. Three air bearing sliders were analyzed and designed by finite element method. Preload technologies were adopted to improve air bearing＇s static performance. The experiment results show that the air-bear- ing sliders have high load capability and stiffness. The static stiffness of X-slider in the vertical direction is 276.9 N/μm and that of Y-slider is 333.3 N/μm. The dual linear motors of H-type stage require high-preci- sion synchro-control. Traditional tandem and parallel synchronous control can＇t fulfill the demand. An improved parallel structure synchronous controller based on velocity synchro-error was proposed, which adaptively tuned the PID parameters by fuzzy controllers. The experiment results show that the synchronous velocity precision is improved more than three times by using the improved synchronous controller, which is suitable for multi-motor synchronization control with strong mechanical coupling. H-type air bearing positioning stage driven by linear motors has high load capability （40kg） and high accuracy （ 〈2 μm） and suits to be used in precision engineering.