• Opto-Electronic Engineering
  • Vol. 44, Issue 8, 842 (2017)
Yanjun Zhang1、2, Yinan Zhang1, Xinghu Fu1、2, and Huimin Wang1
Author Affiliations
  • 1School of Information Science and Engineering, Yanshan University, Qinhuangdao 066004, China
  • 2The Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province, Yanshan University, Qinhuangdao 066004, China
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    DOI: Cite this Article
    Yanjun Zhang, Yinan Zhang, Xinghu Fu, Huimin Wang. Fiber Bragg grating torque sensor with the adjustable range spoke structure[J]. Opto-Electronic Engineering, 2017, 44(8): 842 Copy Citation Text show less

    Abstract

    The torque parameters of the mechanical equipment can reflect the performance of the rotating power mechanical system and provide scientific data for the parts to be measured. Compared with the electric and magnetic torque sensors, FBG sensors have many advantages such as high temperature resistance, radiation resistance, safety and reliability. Using the spoke structure as the elastic element, an adjustable range FBG torque sensor is designed. The FBG torque sensor mainly consists of an inner wheel hub, an outer wheel hub, four elastic plates, a coupling and FBG. Two FBGs with different central wavelengths are symmetrically bonded on the upper and lower surfaces of the elas-tic plate parallel to the axial direction, respectively, as sensing elements and reference elements. In the packaging process, by applying slight adjustable pre-stressing on both sides of the FBG, it can effectively prevent the contrac-tion of FBG in the curing process, as well as the chirp of FBG reflection spectrum and nonlinear distortion of center wavelength. When the torsion force is applied to the hub, two FBGs are subjected to tension and pressure respectively, leading to the center wavelength of the grating moving to opposite directions. By calibrating the relationship between the torque values and the central wavelength difference between the two reflecting elements, the influence of ambi-ent temperature can be eliminated, and the self compensation function of temperature can be realized. The angle between adjacent elastic plates is 90o, the elastic plate is connected with the inner wheel hub and the outer wheel hub by a bayonet, and is fixed by bolts. At the same time, a new type of elastic plate with double grooves is designed on the basis of strip elastic plate, and the range of the sensor is adjusted by replacing the elastic plate without changing the overall structure of the torque sensor. The inner wheel hub is connected with the coupling, thereby improving the practicability and the versatility of the sensor. The torque sensing model of fiber grating is established and the dimen-sion of spoke structure is optimized by using the finite element simulation software. The finite element simulation and experimental results show that the strain of the elastic element has a linear relationship with the central wave-length difference of two fiber gratings. When the range is 80 Nm, the average sensitivity of the sensor is 27.1 pm/Nm, the correlation coefficient is 0.997, the repeat ability error is 3.23% FS, and the hysteresis error is 1.03% FS.
    Yanjun Zhang, Yinan Zhang, Xinghu Fu, Huimin Wang. Fiber Bragg grating torque sensor with the adjustable range spoke structure[J]. Opto-Electronic Engineering, 2017, 44(8): 842
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