Development of an Angstrom Positioning System

头部研究报告表明，扭转辊摩擦驱动静压轴承型的定位分辨率可达0.2nm。为了实现一种适用于超精密机床和测量机的埃定位系统，提出了一种滚珠轴承型扭辊摩擦传动。制作了具有两轴（x轴和z轴）的定位系统，并对各轴的定位性能进行了分析。x轴采用大尺寸的扭辊摩擦传动和气动导轨，z轴采用小尺寸的扭辊摩擦传动和横辊导轨。x轴的定位分辨率为0.5nm，尽管使用滚珠轴承，但证明了扭辊摩擦驱动可以实现埃位定位。z轴的定位分辨率为10nm，与滚珠丝杠的定位分辨率一样小。通过将工作主轴安装在x台上，将工具柱安装在z台上，进行了金刚石车削试验。通过车削加工得到镜面状表面，因此两轴定位系统可以看作是一台超精密机床。研究表明，采用滚珠轴承型扭辊摩擦传动，可以代替滚珠丝杠，在清洁环境下使用超精密定位系统。

It has been reported by the head investigaor that the positioning resolution of the twist-roller friction drive hydrostatic bearing type can be 0.2nm. In the present reearch, a twist-roller friction drive of ball bearing type is proposed for realizing an angstrom positioning system which can be used in ultraprecision machine tools and measuring machines. A positioning system havibg two-axs (X-axis and Z-axis) was made, and the positioning performance of each axis was analyzed. The X-asix employs a large size of twist-roller friction drive and an aeroatatic guideway, while the Z-axis employs a small size of twist-roller friction drive and a cross-roller guideway. The positioning resolution of the X-axis was shown to be 0.5nm, and in spite of the use of ball bearings, it is proved that the twist-roller friction drive can realize the angstrom positioning. The positioning resolution of the Z-axis was 10nm, which is as small as the positioning resolution of the ball screw. A diamond turning test was executed by mounting a work spindle on the X-table and a tool post on the Z-table. A mirror-like surface was obtained by turning, thus the two-axs positioning system can be regarded as an ultra-precision machine tool. The research concludes that the twist-roller friction drive of ball bearing type facilitates the manufacture of an ultraprecision positioning system which can be used in as clean environement, and can take the place of the ball screw.