Reaearch and fabrication of FBG displacement sensor with pressure rod
Based on mechanism of transmission between elastic strain of optical fiber and axial deformation of cylindrically helical compression spring,a fiber Bragg grating(FBG)displacement sensor with pressure rod is proposed.The relationship formula between wavelength shift and the free end displacement of compression spring is derived.Strain transfer packaging with FBG clamps at both ends,and the elastic conversion structure is composed of compression spring,spring tube and tightening device.The sensor prototype is fabricated by using spring elements with wire diameter of 0.6 mm,pitch diameter of 6 mm and effective number of coils of 14.The static performance and temperature response characteristics are studied by calibration test.Test results show that within the range of 15 mm,the displacement sensitivity of the sensor is 451.36pm/mm,the linearity is 0.69％,the repeatability is 1.54％,and the hysteresis is 1.13％.The temperature sensitivity of the strain grating and temperature compensation grating are 10.15pm/℃ and 19.18 pm/℃,respectively;and the errors are 1.39％and 1.50％,respectively,which shows good temperature compensation effect.
万方数据
维普
