时栅位移传感器的绝对式实现方法主要采用单对极+多对极和多对极差一对极组合两种形式实现。对于两层传感器结构的单对极+多对极的组合形式,由于极对数相差较多、分辨力差别较大,不利于实现高精度。对于差一对极的组合方式,由于极对数较多,在传感器原始加工精度较差时,会产生位置解算困难、甚至无法正确解算的情况。为解决上述问题,提出对极数呈互质关系的两层传感器结构的新组合模式。该模式可实现自校正,有效提高产品精度。通过试验验证了该方法的可行性,获取的传感器精度为-4.5″-3.9″。
At present, the absolute measurement method for time-grating displacement sensors mainly adopts two methods. One way, the combination of single and multiple pole pairs in a two-layer sensor structure, features a great pole- pair number difference,leading to a great resolution difference and going against achieving high precision. The other way, the combination of multiple pole pairs with the pole pair number in one set one less than that in the other one, can cause difficulties in resolving positions and even incorrect calculations due to the sensor' s poor manufacturing precision and a considerable pole-pair number in it. In order to solve these problems ,a new method using a two-layer sensor structure with cop-rime pole pair numbers is proposed. This method can implement self-calibration to effectively improve product precision. Finally, the feasibility of the method is verified by experiment, and the precision of the sensor is obtained to be -4.5" -3.9".