关键词: 位移测量；光栅；图像处理；李萨如图；交流伺服

Abstract:

A new method was put forward to get movement displacement directly when applying standard reticle to AC servo driving control system to carry on high precise orientation for a very small object. Adjusting the optical path until grating reticle image can be collected clearly by CCD. After analyzing and processing the grating reticle image collected by CCD, the mapping coefficient can be accurately calculated from grid size to pixels. Comparing the fore-and-aft two grating reticle images after the worktable moved. Adopting phase difference ratio arithmetic based on Lissajous figures,the phase difference of two images will be figured out. The displacement of the worktable can be further calculated by the mapping coefficient. The experimental result shows that this method can easily implement sub-pixel measurement in micro-electronics manufacture quickly.

Key words: displacement measurement；grating；image processing；Lissajous figure；AC servo