There is urgent demand for new absolute Linear Displacement Measurement (LDM) technology with high resolution and high precision, during the development of high-end numerical control technology. In previous research, we found that displacement measurement based on the image processing method performs well, however, the volume increases when using an imaging lens, and the system is susceptible to factors such as virtual focus. In this paper, the lensless LDM image optical path is established based on grating projection imaging, then the absolute grating coding method is operated based on M−sequence pseudo-random coding. A linear displacement subdivision algorithm is then deployed based on the digital image recognition algorithm. An LDM device with a measuring range of 250 mm was designed to test the performance of the proposed method. The device shows a measurement resolution of 1 nm and measurement accuracy of 1.76 μm in the range of 250 mm. This work lays a foundation for further research on high performance LDM technology.

在高端数控技术的发展过程中，迫切需要具有高分辨率和高精度的新型绝对线性位移测量（LDM）技术。在以往的研究中，我们发现基于图像处理方法的位移测量表现良好，但使用成像镜头时体积增加，系统容易受到虚焦等因素的影响。本文在光栅投影成像的基础上建立无透镜LDM图像光路，然后采用基于M-序列伪随机编码的绝对光栅编码方法。然后基于数字图像识别算法部署线性位移细分算法。测量范围为 250 mm的 LDM 设备 旨在测试所提出方法的性能。该器件示出了1:1的测量分辨率 纳米和1.76μ测量精度米中的250的范围内 毫米。这项工作为进一步研究高性能 LDM 技术奠定了基础。