提高圆光栅测角系统精度的读数头设计

Read-head design for improving the precision of circular grating angular measuring system

为了有效提高圆光栅测角系统精度,从布置方式及数据处理方式两方面设计了读数头。提出了通过对主光栅刻划误差进行谐波分析来合理布置读数头的方法,经分析采用四均布读数头的布置方式,可以减少主光栅刻划误差82.6%的谐波分量。与传统的模拟量相加数据处理方式相比,数字量相加数据处理方式可以更有效提高测角系统的测角精度和可靠性。分别检测了圆光栅测角系统在单读数头结构和采用数字量相加的四均布读数头结构时的精度,采用单读数头结构时的测角精度为1.15″,采用数字量相加的四均布读数头结构时的测角精度为0.33″。因此相比较单读数头结构和模拟量相加数据处理方式,四均布读数头和数字量相加数据处理方式能更有效的提高圆光栅测角系统的测角精度。

To improve the precision of the circular grating angular measuring system, a read-head is designed from the aspect of position and data processing. For reasonably positioning the read-head, the lithograph error harmonic of main grating is analyzed. The system adopts four average read-heads to decrease 82.6% lithograph error harmonic of main grating. Compared with the simulative addition technology, the digital addition technology can improve the precision and the reliability of system effectively. At last, the precision of the grating angular measuring system is measured in case of using one read-head and four average read-heads. The precision in case of using one readhead is 1.15＂, the precision in case of using four average read-heads and digital addition is 0.33＂. Therefore, the conclusion is that the precision of circular grating system can be improved by using four average read-heads and digital addition technology.