A temperature-independent force transducer using one optical fiber with multiple Bragg gratings

Abstract

Typical electrical or piezoelectric force sensors may fail in the industrial applications with strong electromagnetic interference (EMI). To address this issue, this paper develops a new temperature-independent force transducer based on theories of elastic cantilever beam and Bragg wavelength shift in fiber Bragg gratings. The detailed design of the structure and theoretical analysis are given to introduce the measurement principle of the transducer and temperature compensation of fiber Bragg gratings (FBG). Extensive experiments have been conducted to evaluate the performance of the developed force transducer. Experimental results demonstrate that the developed FBG force transducer has a force sensitivity 84.43 pm/kN within a measured range from 0 to 50 kN, which is consistent with the theoretical sensitivity 87.77 pm/kN. Moreover, experimentally the transducer also achieves good linearity, repeatability and temperature independency. The developed force transducer can assist in monitoring the states of heavy-duty machines in the harsh industrial environment.