A Diaphragm-Type Highly Sensitive Fiber Bragg Grating Force Transducer With Temperature Compensation

This paper presents a novel diaphragm-type fiber Bragg grating (FBG) force transducer with a high sensitivity through combining the axial property of the optical fiber and the transverse property of a circular diaphragm. The theoretical model of the presented sensor was derived, and its sensing characteristics were analyzed by numerical simulation and finite element analysis. A specimen of this type of sensor was manufactured with a 0.6mm-thickness diaphragm and a 0.1-ratio of the radius of the hard core and the outer radius of the diaphragm. Experiments were conducted to show that its experimental force sensitivity 441.84 pm/N was consistent with the theoretical value 422.4 pm/N within a working range of 0~4.9 N, which verified the effectiveness of the proposed theoretical model. Moreover, experimentally the designed transducer provided a broad flat frequency range from 0 to 200 Hz and a dynamic resolution of 0.15 mN·(Hz
^-0.5
). The temperature cross-sensitivity of this sensor was suppressed effectively in the range of 16.7 °C~53.6 °C after implementing the temperature compensation. Compared with the existing FBG force sensors, the proposed sensor provided higher and more easily adjustable sensitivity.