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

Lookup NU author(s): Professor Gui Yun TianORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


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.

Publication metadata

Author(s): Lu X, Tian G, Wang Z, Li W, Yang D, Li H, Wang Y, Ni J, Zhang Y

Publication type: Article

Publication status: Published

Journal: Sensors

Year: 2022

Volume: 22

Issue: 16

Online publication date: 19/08/2022

Acceptance date: 17/08/2022

Date deposited: 13/09/2022

ISSN (electronic): 1424-8220

Publisher: MDPI


DOI: 10.3390/s22166234

PubMed id: 36015994


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