Long-range real-time position detection for 2D planar electric motorized stage based on machine vision

This paper proposes an accurate and rapid position measurement method for 2D planar macro-motion stages. Firstly, integrating two sets of orthogonally configured 1D line scan cameras and measurement stripes, a position measurement system for the planar electric motorized stage is constructed to realize real-time image acquisition during mover movement. Secondly, based on information entropy theory, the blackand-white line-width difference of the measurement stripes is maximized to enhance the position matching accuracy. Finally, a coarse and fine step-by-step matching long-range real-time position detection method for two-dimensional planar based on sum of absolute differences (SAD) is proposed. The experimental results show that the linearity of the measurement system is 0.043%@40 mm and 0.045%@40 mm in the X- axis and Y -axis, respectively, which verifies the feasibility of the proposed planar 2D real-time visual long-range position measurement method.