Development of an Angstrom Positioning System

据研究负责人报告，扭辊摩擦传动静压轴承型的定位分辨率可达0.2nm。本文提出了一种滚珠轴承扭辊摩擦传动，用以实现超精密机床和测量机的埃定位系统。研制了一套双轴（X轴和Z轴）定位系统，并对各轴的定位性能进行了分析。X-asix采用大尺寸的扭辊摩擦驱动和气动导轨，而Z轴采用小尺寸的扭辊摩擦驱动和交叉辊导轨。X轴的定位精度为0.5nm，证明了即使采用滚珠轴承，扭辊摩擦传动也能实现埃级定位。Z轴的定位分辨率为10 nm，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工作台上并将刀架安装在Z工作台上来执行金刚石车削测试。通过车削加工获得了镜面状的加工表面，因此该双轴定位系统可以看作是一台超精密机床。研究结果表明，滚珠轴承式扭辊摩擦传动可代替滚珠丝杠副，制成超精密定位系统，可作为洁净设备的精密定位系统。

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.