拼接式钢带光栅编码器测角误差分析与修正

针对望远镜对高精度测角技术的要求，分析了机械安装偏心、加工椭圆度误差、轴系晃动等对新型拼接式钢带光栅编码器测角的影响，并制定了相位差为90°的4读数头软件细分测角方案。在机械安装偏心为10μm、加工椭圆度为2μm、轴系晃动为0.6″的实验平台上进行了逆时针和顺时针测角实验，两组实验测角误差RMS值分别为0.393″和0.488″。实验表明：该测角方案能消除机械安装偏心、加工椭圆度误差等对测角数据的影响，实现了亚角秒级测角。

Error analysis and correction of scale tape grating encoder

To satisfy rigid performance specifications of goniometry for a telescope , this paper analyzes the im-pacts of the mechanical installation eccentric , roundness error and the shafting sloshing on angle measurements by an encoder with a scale tape grating , and develops a software subdivision angle measurement program based on 4 reading heads and 90°phase difference.The counterclockwise and clockwise angle measuring experi-ments are performed on a experimental platform with a mechanical installation eccentric of 10 μm, roundness error of 2 μm and shafting sloshing of 0.6″.The measuring angle error RMS values from two sets of experi-ments are 0.393″, 0.488″, respectively.The experiments prove that the program can eliminate the angular measurement errors caused by the mechanical installation eccentric , machining roundness error and the shaft-ing sloshing.It achieves arcsecond angle measurements .