Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Tsinghua-Berkerley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China.
Sensors (Basel). 2023 Apr 15;23(8):4022. doi: 10.3390/s23084022.
A compact and high-precision three-degrees-of-freedom (DOF; X, Y, and Z directions) grating encoder based on the quadrangular frustum pyramid (QFP) prisms is proposed in this paper to solve the insufficient installation space problem of the reading head of the multi-DOF in high-precision displacement measurement applications. The encoder is based on the grating diffraction and interference principle, and a three-DOF measurement platform is built through the self-collimation function of the miniaturized QFP prism. The overall size of the reading head is 12.3 × 7.7 × 3 cm and has the potential for further miniaturization. The test results show that three-DOF measurements can be realized simultaneously in the range of X-250, Y-200, and Z-100 μm due to the limitations of the measurement grating size. The measurement accuracy of the main displacement is below 500 nm on average; the minimum and maximum errors are 0.0708% and 2.8422%, respectively. This design will help further popularize the research and applications of multi-DOF grating encoders in high-precision measurements.
本文提出了一种基于四角棱台（QFP）棱镜的紧凑、高精度的三自由度（X、Y 和 Z 方向）光栅编码器，以解决多自由度读数头在高精度位移测量应用中的安装空间不足问题。该编码器基于光栅衍射和干涉原理，通过小型化 QFP 棱镜的自准直功能构建了一个三自由度测量平台。读数头的整体尺寸为 12.3×7.7×3cm，具有进一步小型化的潜力。测试结果表明，由于测量光栅尺寸的限制，在 X-250、Y-200 和 Z-100μm 的范围内可以实现三自由度测量。主要位移的测量精度平均低于 500nm；最小和最大误差分别为 0.0708%和 2.8422%。该设计将有助于进一步推广多自由度光栅编码器在高精度测量中的研究和应用。
