A high-sensitivity temperature-compensated fiber grating acceleration sensor

Abstract

The invention provides a high-sensitivity temperature compensation type fiber Bragg grating acceleration sensor, which comprises a cubic shell (1), a double-arched elastic structure beam (2) fixed ona shell panel, and double fiber Bragg gratings, i.e., a 1# fiber Bragg grating (5) and a 2# fiber Bragg grating (6) fixed on the double-arched elastic structure beam, wherein the middle of the double-arched elastic structure beam (2) is provided with a vertical beam (22); one side of the shell (1) is fixedly provided with rigid sliding rods (8) and a damper (10); a mass block (9) is positioned onthe rigid sliding rods (8) and is connected with the damper (10); and one end of a prestressed spring (7) is fixed on the vertical beam (22), and the other end of the prestressed spring (7) is fixed on one side of the mass block (9). By use of the sensor, the double-arched elastic structure beam is used for fixing double fiber Bragg gratings below the arched beam, so that the sensitivity of the fiber Bragg grating acceleration sensor is greatly improved, tail fibers on two ends of the sensor are both free ends so as to be connected with other fiber Bragg grating sensors in series, and a sensing array or network can be formed to realize distributed sensing.

Description

technical field [0001] The invention relates to a high-sensitivity temperature self-compensating optical fiber grating acceleration sensor, which belongs to the field of optical fiber sensing. Background technique [0002] The measurement of acceleration plays an important role in structural health monitoring of machinery, aviation, ships, etc., as well as in inertial navigation and guidance systems. At present, there are various methods of measuring acceleration, which can be mainly divided into three types: electrical, mechanical and optical. Among them, the electrical acceleration sensor has the advantages of high sensitivity, wide frequency range, dynamic range and linear range, and is convenient for analysis and telemetry, but it is easily affected by electromagnetic interference and harsh environments such as high temperature and high pressure. The mechanical acceleration sensor has strong anti-interference ability, but its frequency range, dynamic range and linear ra...

AI Technical Summary

Problems solved by technology

This solution generally glues the fiber grating on the structural beam directly. On the one hand, it is easy to cause the wavelength of the fiber grating to chirp, and on the other hand, the flexibility of the structural beam does not change much, resulting in low sensitivity of the sensor.

In addition, the fiber grating itself is not only sensitive to stress, but also very sensitive to changes in the external temperature. Most of the solutions that only package the fiber grating on the structural beam do not consider the temperature sensitivity of the fiber grating, resulting in temperature cross-sensitive measurement results. question

In CN108982916A, Li Jianzhi and others have designed a high-sensitivity fiber grating acceleration sensor, which connects the fiber grating to the rigid beam hinged by the rotating shaft and the substrate. Although this scheme improves the sensitivity, the swing range of the rigid beam cannot be too large, so that the sensor The dynamic range is small, the optical fiber is easy to break, and there is no temperature compensation unit, so the measurement error is large

People such as Xiong Yanling in CN202975044U have designed a kind of fiber grating acceleration sensor with self-warming compensation function, and it adopts a diamond beam and vibrating beam to form bimetallic structure, eliminates the temperature drift of fiber grating acceleration sensor by bimetal thermal expansion coefficient difference, but diamond shape The thermal expansion coefficient of the beam and vibrating beam is difficult to grasp, and the temperature drift of the fiber grating cannot be completely eliminated. At the same time, this structure makes the dynamic range of the fiber grating small and the sensitivity is reduced

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