Research on the Time Drift Stability of Differential Inductive Displacement Sensors with Frequency Output

Xiaolong Lu; Guiyun Tian; Zongwen Wang; Wentao Li; Dehua Yang; Haoran Li; You Wang; Jijun Ni; Yong Zhang

doi:10.3390/s22166234

Sensors (Aug 2022)

Research on the Time Drift Stability of Differential Inductive Displacement Sensors with Frequency Output

Xiaolong Lu,
Guiyun Tian,
Zongwen Wang,
Wentao Li,
Dehua Yang,
Haoran Li,
You Wang,
Jijun Ni,
Yong Zhang

Affiliations

Xiaolong Lu: School of Mechanical Engineering, Sichuan University, Chengdu 610065, China
Guiyun Tian: School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
Zongwen Wang: School of Mechanical Engineering, Sichuan University, Chengdu 610065, China
Wentao Li: School of Mechanical Engineering, Sichuan University, Chengdu 610065, China
Dehua Yang: College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
Haoran Li: School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
You Wang: National Astronomical Observatories, Nanjing Institute of Astronomical Optics and Technology, Chinese Academy of Sciences, Nanjing 210042, China
Jijun Ni: National Astronomical Observatories, Nanjing Institute of Astronomical Optics and Technology, Chinese Academy of Sciences, Nanjing 210042, China
Yong Zhang: National Astronomical Observatories, Nanjing Institute of Astronomical Optics and Technology, Chinese Academy of Sciences, Nanjing 210042, China

DOI: https://doi.org/10.3390/s22166234
Journal volume & issue: Vol. 22, no. 16
p. 6234

Abstract

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An edge displacement sensor is one of the key technologies for building large segmented mirror astronomical optical telescopes. A digital interface is one novel approach for sensor technologies, digital transformation and the Internet of Things (IoT) in particular. Frequency output sensors and inductance-to-digital converter (LDC) demonstrated significant advantages in comparison with conventional sensors with analog-to-digital converter (ADC) interfaces. In order for the differential inductive frequency output displacement (DIFOD) sensor to meet the high-stability requirements of segmented mirror astronomical telescopes, it is important to understand the factors for time drift of the sensor. This paper focuses on the investigation of key factors of sensor structure and material, signal conditioning and interface, and fixtures for time drift to permanently installed applications. First, the measurement principle and probe structural characteristics of the sensor are analyzed. Then, two kinds of signal conditioning and digitalization methods using resonance circuits and LDC chips are implemented and compared. Finally, the time drift stability experiments are performed on the sensors with different signal conditioning methods and fixtures under controlled temperature. Experimental results show that the magnetic shield ring effectively improves the sensitivity and quality factor of the sensors, the time drift stability of the sensor using the signal conditioning based on resonance circuits is better than that of the sensors using LDC chips, and the root mean square (RMS) of the sensor time drift meets the requirement of 0.01 μm/24 h. This study will help further development of high-stability of frequency output sensors and IoT-based systems for scaled-up applications in the future.

Published in Sensors

ISSN: 1424-8220 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Chemical technology
Website: http://www.mdpi.com/journal/sensors

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