Calibration Method of Grating Moiré Signal Subdivision Error Based on Laser Interference Principle

Abstract

The invention discloses a grating Moire signal subdivision error calibration method and solves the problem in the prior art that the existing subdivision error calibration is incomplete. According tothe invention, an initial displacement l0 is measured by a laser interferometer, and a grating is controlled to march at a step pitch of h. meanwhile, a displacement X corresponding to a subdivision value is set. A displacement measurement result li of a laser interferometer at the jump moment of each subdivision value of an n-rate subdivision circuit within one displacement of the grating is recorded. After that, the difference value li-l0 of the displacement measurement result of the laser interferometer is adopted as a reference value to be compared with the measurement value iX of the subdivision displacement of the grating, so that the displacement deviation delta i of each subdivision value is obtained. The displacement deviation of each subdivision value within one pitch is subjected to data processing, and then a subdivision error is obtained. The measurement is repeated, and then the average value of a plurality of groups of measurement values is adopted as the subdivision error of a grating moire signal. The method is short in calibration time, simple in data processing and high in testing efficiency.

Description

technical field [0001] The invention relates to the technical field of grating moiré fringe subdivision, in particular to a method for calibrating the subdivision error of grating moiré signals. Background technique [0002] Grating measurement technology has always been an important part of the measurement field. The signal processing method of subdividing the grating moiré signal to improve the measurement resolution and accuracy is widely used in the field of high-precision measurement. The errors introduced by grating moiré signal interpolation during grating measurement need to be evaluated. [0003] At present, domestic calibration methods for subdivision errors are not perfect, and most studies only consider part of the errors caused by the non-standard output signal of the grating, but do not include the errors introduced by the subdivision algorithm and the realization of the subdivision function. For example, in the invention patent "Detection Device for Subdivis...

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