High displacement resolution encoder by using triple grating combination interferometer

Hsu, C. S.; Chen, Hang; Tseng, Hsien-Yao; Lan, Shih-Chieh; Lin, Jie

doi:10.1016/j.optlastec.2018.03.005

Cited by 22 publications

(9 citation statements)

References 18 publications

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“…Then, θ represents the rotation angle between two gratings, and W represents the distance between two stripes. The moiré fringe equation after grating overlap can be obtained by this coordinate system [23][24][25][26][27]. The focal length and moiré fringe relationship of a symmetric optical system can be derived by the moiré fringe equation.…”

Section: Moiré Fringe Equationmentioning

confidence: 99%

Research on Focal Length Measurement Scheme of Self-Collimating Optical Instrument Based on Double Grating

Yang

Wang

Shen

et al. 2020

Sensors

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In this paper, we propose a scheme for measuring the focal length of a collimating optical instrument. First, a mathematical model for measuring the focal length of a collimator with double gratings is derived based on the moiré fringe formula and the principles of geometric optics. Mathematical simulation shows that a slight difference in the focal length of two collimators has an important influence on the imaging law of moiré fringes. Our solution has a good resolution ability for focal length differences within 5‰, especially in the small angle range below 4°. Thus, the focal length of collimators can be measured by the amplification of the slight difference. Further, owing to the relative reference measurement, the measurement resolution at the symmetrical position of focal length is poor. Then, in the designed experiment, a corresponding moiré image at different angles is acquired using collimators with known focal length. The experimental results indicate that the root mean square error (RMSE) of the collimator corresponding to grating angles of 2°–4° is better than 4.7‰, indicating an ideal measurement accuracy of the proposed scheme. This work demonstrates that our proposed scheme can achieve an ideal accuracy in the measurement of a symmetrical optical path.

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Section: Moiré Fringe Equationmentioning

confidence: 99%

Research on Focal Length Measurement Scheme of Self-Collimating Optical Instrument Based on Double Grating

Yang

Wang

Shen

et al. 2020

Sensors

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“…Compared with the other two methods, displacement measurement based on the autocollimator principle has important application value, especially in two-dimensional displacement 2 of 11 measurement, which is worth researching. In reality, an interferometer is usually large in size with a high cost in many applications [16]. Moreover, the displacement measurement based on internal-reflection is limited by the measurement range, the geometric accuracy of the reflection prisms, and material inhomogeneity [17].…”

Section: Introductionmentioning

confidence: 99%

A Novel 2D Micro-Displacement Measurement Method Based on the Elliptical Paraboloid

et al. 2019

Applied Sciences

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The micro-displacement measurement system with 2D/3D has become increasingly important in the field of scientific research and technology application. In order to explore the application of an optical surface in micro-displacement measurement, a novel and simple 2D micro-displacement measurement method based on the elliptical paraboloid was designed and subjected to experiment. The measurement system takes advantage of the elliptical paraboloid instead of a plane mirror in the optical structure of an autocollimator which has been ameliorated to adapt to curved surface measurement. Through the displacement of the light spot on the CCD (Charge Coupled Device) detector, the displacement of the target could be measured with a linear correlation coefficient of 0.9999. The accuracy of the system is about ± 0.3 µm in a wide range in two dimensions. The results were in good agreement with the theoretical analysis and indicated the potential applicability of the proposed system in the detection of geometric errors of CNC (Computerized Numerical Control) machine tools.

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“…Displacement measurements are fundamentally important in industrial applications, and the displacement sensors are gaining more important attention in the increasing automated industry [ 1 ]. Kinds of displacement sensors have been proposed, including capacitive displacement sensors [ 2 ], eddy-current sensors [ 3 ], linear variable displacement transformer (LVDTs) [ 4 ], linear optical grating [ 5 ], laser interferometers [ 6 ], and magneto-strictive displacement sensors [ 7 ]. The displacement measurement resolution of these sensors is as high as a nanometer level with hundreds of millimeters, which plays a key role in automation control application.…”

Section: Introductionmentioning

confidence: 99%

Optical Fiber Displacement Sensor Based on Microwave Photonics Interferometry

Dong

Liu

Yang

et al. 2018

Sensors

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An optical fiber displacement sensor based on the microwave photonics interferometric (MWPI) method is proposed and experimented, which provides an ideal solution for large range displacement measurement with high resolution. The sensor used a Michelson microwave photonics interferometer to sense the displacement with one sensing arm and a length-adjusted reference arm. The displacement variation would change the period of the microwave response function of the interferometer. According to the principle that the phase difference in one free spectral range (FSR) of the microwave response function is 360°, the displacement can be retrieved by the microwave response function by means of a vector network analyzer (VNA). A programmable path-switching true time delay line was used in the reference arm to decrease the microwave bandwidth. The measurement results show that the displacement sensing range is larger than 3 m and the measurement resolution is 31 μm. Finally, the measurement stability is tested, and the factors affecting the measurement resolution of this method and the main source of errors are investigated in detail.

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High displacement resolution encoder by using triple grating combination interferometer

Cited by 22 publications

References 18 publications

Research on Focal Length Measurement Scheme of Self-Collimating Optical Instrument Based on Double Grating

Research on Focal Length Measurement Scheme of Self-Collimating Optical Instrument Based on Double Grating

A Novel 2D Micro-Displacement Measurement Method Based on the Elliptical Paraboloid

Optical Fiber Displacement Sensor Based on Microwave Photonics Interferometry

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