High-Resolution Angular Displacement Technology Based on Varying Moiré Figure Phase Positions

Abstract

Angular displacement measurement is a popular research subject. The grating of traditional angular measurement devices uses multi-circle code and is difficult to miniaturize. This paper proposes a novel angular displacement technology based on varying moire figure phase positions which allows for reduced volume and high-resolution angle measurements in small-size gratings. First, a moire figure phase model is established and the calculation arithmetic is written. Second, the proposed arithmetic based on differences in moire figure phase positions is completed accordingly. At last, a test device was fabricated based on the proposed theory with a total diameter of 35 mm and grating diameter of 25 mm. These tests show that angular displacement method based on differences of moire figure phase positions can achieve a high resolution measurement when the diameter of calibration grating is small. We hope the results of this paper provide a workable theoretical foundation for future photographic encoders.