Abstract:

In the course of asphere contact-type measurement,the pneumatic control probe with aerostatic bearing was adopted to decrease the pressure where measuring probe acted on measured surface and the frictional force of the probe in the motion.A pneumatic control probe was designed herein for ultra-precision asphere measurement,the size of the square aerostatic bearing was calcuated by engineering algorithm,and three kinds of bearing model with different throttle orifices were established.At the same time,the finite element models for the internal air flow in the three bearing and the probe on the working status  were established respectively.The pressure distribution,pressure intensity and air flow rate of the above flow model were simulated by using Fluent fluid calculation software,and the probe static performance was also forecasted.The results show that the stiffness of the probe can reach 1.77MN/m,the magnitude of contact force between the probe and measured surface can be controlled in 0.1~7mN,the maximum consumed air flow can reach 3.6m3/h,and it meets the design requirements of the probe.

Key words: asphere, pneumatic control probe, aerostatic bearing, air space, simulation

摘要：

非球面接触式测量过程中，采用空气静压轴承的气浮式测头，可以减小测量探针对被测表面的压力和测头移动过程中所受的摩擦力。设计了一种非球面超精密气浮式测头，采用工程算法对其方形空气静压轴承进行了尺寸设计，建立了三种采用不同节流孔形式的轴承设计模型，同时分别对这三个轴承工作时内部的气流以及整个测头内部的气流建立了有限元模型，并采用Fluent流体计算软件对以上气流模型的气压分布、压强以及流量进行了仿真计算，预测了测头的静态性能。结果表明,测头刚度可达1.77MN/m,测头与被测表面之间的接触力可控制在0.1~7mN之间,所消耗空气流量最多为3.6m3/h，满足测头设计要求。

关键词: 非球面, 气浮式测头, 空气静压轴承, 气腔, 仿真