An absolute grating ruler test platform and its test method

Abstract

The invention relates to a test platform for an absolute grating ruler. The test platform for the absolute grating ruler comprises a complementary metal oxide semiconductor (COMS) sensor, an optical focusing mirror, a COMS eye lens, a collimated light source, a grating ruler supporter, a double-grating-strip grating ruler, a grating ruler supporter, a mobile platform, a linear slide rail, a linear propulsion system, a stepping motor and a base, wherein a linear movement system is composed of the stepping motor, the linear propulsion system and the linear slide rail, and a sampling system of image processing is composed of the COMS sensor, the optical focusing mirror, the COMS eye lens, the collimated light source and the double-grating-strip grating ruler. According to the test platform and the test method for the absolute grating ruler, accuracy and reliability of encoding measurement are improved, so that accurate positioning can be achieved. The test platform for the absolute grating ruler has the advantages of high accuracy, high controllability and high reliability. The invention aims at providing a method for the absolute grating ruler of double encoding strips with optical amplification. In addition, through reasonable and reliable image analysis and closed-loop control, mobility, reliability and accuracy of the grating ruler are enabled to be greatly improved.

Description

technical field [0001] The invention relates to an absolute grating ruler testing platform and a testing method thereof, and belongs to the innovative technology of the absolute grating ruler testing platform and the testing method thereof. Background technique [0002] The principle of the grating scale is based on the Moiré fringes produced by the grating scale interference or diffraction. British physicist L.Rayleigh first proposed the engineering value of this pattern in 1874. The measurement principle of grating ruler can be divided into image principle and interference principle. The grating ruler based on the image principle generally has a large grating pitch, ranging from 100 μm to 20 μm, which is much larger than the wavelength of the light wave of the light source. When the two gratings move relative to each other, a low-frequency beat phenomenon is generated to form moiré fringes. The resolution of this grating scale is at the micron level and submicron level. ...

AI Technical Summary

Problems solved by technology

The design method of 4 frequency doubling technology has been developed so far. Although it is quite mature, there are some shortcomings, such as complicated principles, complicated circuit design, and relatively high requirements.

[0005] Due to the complexity of the absolute position grating encoding and the complexity of the closed-loop control algorithm, the fully closed-loop double-coded bar-coded grating ruler has not been developed on a large scale in China.

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