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Journal of Sensors
Volume 2018, Article ID 1342593, 11 pages
https://doi.org/10.1155/2018/1342593
Research Article

Analysis and Design of an Effective Light Interference Methane Sensor Based on Three-Dimensional Optical Path Model

Teng Long,1,2 En Li,1,2 Lei Yang,1,2 Junfeng Fan,1,2 and Zize Liang1,2

1The State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, 95 Zhongguancun East Road, Beijing 100190, China
2University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China

Correspondence should be addressed to En Li; nc.ca.ai@il.ne

Received 12 December 2017; Revised 24 May 2018; Accepted 4 June 2018; Published 10 July 2018

Academic Editor: María del Carmen Horrillo

Copyright © 2018 Teng Long et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

As an important environmental monitoring equipment, the existing methane sensors or the traditional interferometer-based methane detectors have some drawbacks, such as low accuracy, large size, and complex calibration operations. Moreover, the optical path model and analysis method for the light interference methane sensor are not practical. In this paper, an effective light interference methane sensor is proposed based on a three-dimensional optical path model with point light source. Based on this model, the interference optical system is studied to illustrate the cause of the interference fringes. Furthermore, the influencing factors of the light intensity distribution are analyzed and an adjustment method for the interference fringes is proposed, which helps to simplify the assembling and calibrating operations. In order to improve the measurement accuracy, a temperature drift compensation method which includes a mapping table, a steady-state compensator, and a dynamic compensator is proposed. The mapping table is established between the output voltages of photoelectric detector, and the methane concentration, the steady-state compensator, and the dynamic compensator are proposed to eliminate the temperature drift. Finally, an experimental device for the light interference methane sensor is constructed to validate the interference fringe adjustment method and the temperature drift compensation method.