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2025 , Vol. 30 >Issue 2: 337 - 351

DOI: https://doi.org/10.1007/s12204-023-2665-0

Automation & Computer Science

New Encoder Based on Grating Eddy-Current with Differential Structure

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  • Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

Accepted date: 2023-01-03

  Online published: 2025-03-21

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Abstract

In response to the shortcomings of the common encoders in the industry, of which the photoelectric encoders have a poor anti-interference ability in harsh industrial environments with water, oil, dust, or strong vibrations and the magnetic encoders are too sensitive to magnetic field density, this paper designs a new differential encoder based on the grating eddy-current measurement principle, abbreviated as differential grating eddy-current encoder (DGECE). The grating eddy-current of DGECE consists of a circular array of trapezoidal reflection conductors and 16 trapezoidal coils with a special structure to form a differential relationship, which are respectively located on the code plate and the readout plate designed by a printed circuit board. The differential structure of DGECE corrects the common mode interference and the amplitude distortion due to the assembly to some extent, possesses a certain anti-interference capability, and greatly simplifies the regularization algorithm of the original data. By means of the corresponding readout circuit and demodulation algorithm, the DGECE can convert the periodic impedance variation of 16 coils into an angular output within the 360◦ cycle. Due to its simple manufacturing process and certain interference immunity, DGECE is easy to be integrated and mass-produced as well as applicable in the industrial spindles, especially in robot joints. This paper presents the measurement principle, implementation methods, and results of the experiment of the DGECE. The experimental results show that the accuracy of the DGECE can reach 0.237% and the measurement standard deviation can reach ±0.14 ◦ within 360 ◦ cycle.

Cite this article

Zhang Zaiyi, Lv Na, Tao Wei, Zhao Hui . New Encoder Based on Grating Eddy-Current with Differential Structure[J]. Journal of Shanghai Jiaotong University(Science), 2025 , 30(2) : 337 -351 . DOI: 10.1007/s12204-023-2665-0

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