Multifunction ActiveAerostatic Coupling for Ultraprecision Positioning System

为提高超精密定位系统的性能，提出了一种多功能有源气动耦合装置。这种空气静压联轴器的特点是有一个主动的空气静压推力轴承，采用该联轴器的定位系统具有以下功能：(1)从驱动机构中隔离振动：驱动机构的横向振动产生数微米量级的工作台振动。通过采用空气静力联轴器，隔离了驱动机构的振动，将工作台的振动降低到纳米量级。(2)提高了推力刚度：空气静力联轴器的使用有效地提高了工作台的运动精度，但进给驱动装置的推力刚度有所降低。通过对联轴器中气体静压推力轴承的主动控制，实现了无限大的推力刚度。在10赫兹的频率范围内，主动控制对动态推力刚度的影响也是显而易见的。(3)超精密定位：主动气动联轴器具有高分辨率短行程定位功能。阶跃定位实验表明，有源空气静力偶合器的定位分辨率至少达到50 pm。该联轴器还以μrad的顺序控制工作台的微旋转。这些功能对提高超精密机床、超精密测量机、大规模集成电路步进机等纳米技术领域的超精密定位系统的定位性能具有重要意义。

A multifunction active aerostatic coupling is proposed for improving the performance of ultraprecision positioning system. This aerostatic coupling is characterized to have an active aerostatic thrust bearing and the positioning system employing the coupling has following functions:(1) Isolation of vibration from the driving mechanism : Lateral vibration of the driving mechanism generates the table vibration in the order of several micrometers. By using the aerostatic coupling, the vibration of the driving mechanism is isolated and the table vibration is reduced to the nanometer order.(2) Improvement of thrust stiffness : The use of the aerostatic coupling is effective for improving the accuracy of the table motion, however, there occurs some decrease in the thrust stiffness of the feed drive device. Active control of the aerostatic thrust bearing in the coupling realizes the infinite thrust stiffness. The effect of the active control on the dynamic thrust stiffness can also be seen to the frequency of 10Hz.(3) Ultraprecision positioning: The active aerostatic coupling has the function of short-stroke positioning with high-resolution. The experiment of step positioning shows that the positioning resolution of the active aerostatic coupling is 50pm at least. The coupling also controls the micro rotation of the table in the order of μrad. These functions are effective for improving the positioning performance of the ultraprecision positioning system used in the several fields of nanotechnology, such as ultraprecision machine tool, ultraprecision measuring machine, and stepper for LSI.