新型磁悬浮精密定位平台的研究

New Magnetically Levitated Precision Positioning Stage

针对磁悬浮精密定位平台的运动稳定性问题,设计了一种新型六自由度磁悬浮精密定位平台.该平台采用12个空心电磁线圈做定子、36块永磁体做动子,悬浮部分与驱动部分相互独立,从而很好地解决了由电磁线圈铁心引起的非线性以及悬浮与驱动单元之间的相互耦合问题.采用罗仑兹定律,分析了永磁体长度、线圈电流和悬浮位移对悬浮稳定性的影响,确定了平台的悬浮平衡位置,建立了平台在平衡位置附近的悬浮数学模型,并进行了动态响应仿真研究.研究结果表明,该磁悬浮精密定位平台在悬浮电流为2 A、悬浮高度为0.5 mm时可以稳定悬浮,因此可应用于需要超精密定位和超洁净环境的半导体光刻装置中.

To improve the stability of the magnetic levitation system,a novel scheme of six-degree of freedom magnetically levitated precision positioning stage is designed, where 12 air core electromagnetic coils and 36 permanent magnets are employed as the stator and mover respectively, and the levitation and linear drive parts of the stage are separated, thus the coupling between them is minimized and the nonlinearity due to the ferromagnetism is avoided. Based on Lorentz law, some parameters, including the permanent magnets length, currents and levitation displacement, which may affect the stability, are analyzed to determine the equilibrium position. A mathematical model in levitation direction is established and the dynamic response is simulated. The results show that the stage enable to work stably under the conditions with 2 A current and 0.5 mm levitation height. The stage is especially suitable for semiconductor photolithography requiring ultra precision positioning and super cleanness.