双电机单元光纤定位机构

Optical fiber positioning unit with two electromotors

通过对天文观测中光纤定位典型方法的分析,结合工程的特点和工作要求,提出了在焦面上进行分区,并且在单元区域内做直线运动和旋转运动的双电机单元光纤定位机构的方法。该方法能到达区域内的任意一点,进而多个单元机构可以到达整个焦面上的任意位置,完成定位光纤的目的。对这一结构进行了原理分析和精度、定位时间的计算,能够满足工程使用要求。用7根单元机构模拟了4000根单元的相互关系,结果表明,机构的重复性误差和目标点定位误差的均方根值的最大值是22.17μm和30.71μm,能够满足望远镜快速、准确的定位要求。

In the LAMOST (Large Area Multi-Object Fiber Spectroscope Telescope) project, 4 000 optical fibers are mounted on a focal plane of 1.75 m in diameter, the position precision is less than 40 microns, and the positioning time is less than 30 minutes. By analyzing the typical method of positioning optical fibers for astronomic observation and taking into consideration the structural characteristics and the operating requirements of LAMOST, a new plan has been brought forward for positioning of optical fibers in a local plane divided into many unit zones. The unit turns round through 360°, and the locomotive block moves in a linear guide in every unit zone. So the optical fiber can reach everywhere in the focal plane. Experiment results show that the standard deviation of repeat error and positioning error are 22.17 μm and 30.71 μm rms, respectively, and the positioning precision of this system can meet the demand.