Applied Sciences (Nov 2021)

LADRC-Based Magnetic Field Measurement Method for a Nuclear Magnetic Resonance Rotation Sensor

  • Xinghua Zhao,
  • Zhanchao Liu,
  • Xinda Song,
  • Jianli Li,
  • Yibo Shao

DOI
https://doi.org/10.3390/app112110458
Journal volume & issue
Vol. 11, no. 21
p. 10458

Abstract

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Magnetic field measurement is fundamental to nuclear magnetic resonance rotation sensors (NMRRS). A phase-locked loop (PLL)-based measurement with two nuclear isotopes is commonly applied to observe the magnetic field. However, the phase-loop and frequency-loop of the nuclear isotopes cannot be optimized simultaneously by a PLL-based method. In this paper, an approach based on a linear active disturbance rejection controller (LADRC) is proposed for synchronous phase-loop control of the two nuclear isotopes. Meanwhile, the frequencies of the nuclear isotopes are observed by linear extended state observers (LESOs). The phase and frequency loops can be decoupled and optimized with the proposed method. An experimental NMRRS prototype used for verification is built. The effectiveness and the feasibility of the proposed method are validated with the experimental results.

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