一种对极数互质的高精度绝对式角位移传感器

A high precision absolute angular displacement sensor with a coprime number of measurement periods

提出了一种对极数互质的高精度绝对式时栅角位移传感器。在N对极的单圈增量电场式时栅角位移传感器的基础上增加一个M对极的传感器,实现组合测量,其中,2个增量式传感器对极数N和M为互质数,对极数多的作为精测部分,保证传感器的测量精度;对极数少的作为粗测部分,利用2个增量式传感器输出行波相位差和空间角度对应关系实现传感器的绝对角位移测量。采用差动感应电极结构消除共模干扰以保证测量精度,这种对极数互质组合测量传感器既能够较容易实现绝对定位,又能够保证传感器的高精度。采用印制电路板技术制造了外径154 mm、内径100 mm、厚度2 mm的传感器样机,搭建了实验平台进行测试,测试结果表明:该传感器的整周测量范围原始精度可达±1.8″。

This paper proposes a high precision absolute time-grating angular displacement sensor with a coprime number of measurement periods.An incremental sensor with M measurement periods is added on the basis of a time-grating angular displacement sensor in the single-ring incremental electric field with N measurement periods so as to achieve combination measurement,among which two period numbers N and M of the incremental sensor are coprime numbers.The one with more measurement periods is used as the precision measurement component to improve the measurement accuracy,the one with fewer measurement periods is used as the rough measurement component,and the absolute angular displacement of the sensor is measured by using the corresponding relationship between the phase difference of the output traveling wave and the spatial angle of the two incremental sensors.The measurement accuracy is ensured by adopting a differential induction electrode structure to eliminate common-mode interference.This sensor with combined coprime numbers of measurement periods can not only easily realize absolute positioning,but also ensure a high accuracy of the sensor.A sensor prototype with an outer diameter of 154 mm,an inner diameter of 100 mm and a thickness of 2 mm is manufactured through the printed circuit board technology.The experimental platform of the sensor is built,and the prototype is tested.The test results show that the original accuracy of the sensor can reach±1.8 in the whole circumference measurement range.