基于自制光栅生成莫尔条纹的微小位移测量装置研究

Research on a Micro-Displacement Measurement Device Generating Moire Fringes Based on a Self-Fabricated Grating

摘要: 针对传统精密光栅制备工艺复杂、成本高昂的问题，本研究基于两组周期性光栅几何叠加产生莫尔条纹的挡光效应机理，利用其显著的位移放大特性，研制了一种利用自制低成本光栅的微小位移测量装置。通过高分辨率菲林胶片打印技术制备亚毫米级直线光栅，并结合XYZR四轴位移平台与USB摄像头模组构建硬件系统。配合Python-OpenCV开发的数字刻线辅助系统，在实时视频流上叠加20等分虚拟标尺，通过计算机辅助目视测量显著提升了读数分辨率。实验数据表明：在光栅常数为0.7 mm、打印精度不低于4000 dpi的条件下，测量相对误差低至0.28%。系统参数分析证实，莫尔条纹的测量特性仅取决于光栅常数，与栅线宽度的分配比例无关。该研究为高精度非接触位移测量提供了一种简便、实用的低成本技术途径。

Abstract: Addressing the complex manufacturing processes and high costs associated with traditional precision gratings, this study leverages the light-blocking effect mechanism of Moire fringes generated by the geometric superposition of two sets of periodic gratings. Utilizing their significant displacement amplification characteristics, we developed a micro-displacement measurement device employing a low-cost, self-fabricated grating. Submillimeter-scale linear gratings were fabricated using high-resolution film printing technology. The hardware system was constructed by integrating an XYZR four-axis displacement stage with a USB camera module. A computer-assisted visual measurement system was developed using Python and OpenCV. By overlaying a calibrated digital reticle on the live video feed, a 20-segment subdivision method was implemented, which significantly enhanced the measurement resolution of the system. Experimental data demonstrate that under conditions of a grating constant of 0.7 mm and a printing precision of no less than 4000 dpi, the relative measurement error is as low as 0.28%. System parameter analysis confirms that the measurement characteristics of Moire fringes depend solely on the grating constant and are independent of the distribution ratio of grating line widths. This research provides a simple, practical, and low-cost technical approach for high-precision non-contact displacement measurement.