2018 Volume 15 Issue 17 Pages 20180694
This paper proposed and studied a simple and novel displacement sensor that stretching two fiber Bragg gratings (FBGs) directly with a developed lever structure. The sensing principle was presented, and the corresponding theoretical model was derived and validated. Experimental results show that this design has an excellent displacement sensitivity of 23.654 pm/µm and a high resolution of 42 nm within a range of 0∼300 µm. The resonant frequency and dynamic working bandwidth of the sensor are 115 Hz and 0∼50 Hz respectively, which were obtained through finite element method (FEM) and modal testing experiment. The difference method was utilized to decouple temperature sensitivity of the FBGs, and the experimental results indicate that the designed sensor shows good temperature independence. This sensor can be utilized for micro-amplitude displacement measurement in harsh industry environment.
