Torque Sensing System Researching Based On Fiber Bragg Grating

In this paper, the sensing principle of fiber grating was deeply analyzed, and arange of100Nm fiber grating torque sensor was designed. In order to meet the needsof the fiber Bragg grating torque measurement, a set of test system suitable for fibergrating torque measurement was set up.Two kinds of different shape of elastic structures, axis and spoke structure, weredesigned. The spoke structure was innovatively used in torque measurement aspects,in order to improve the strain sensitivity of the sensor the rectangular spokes oforiginal spokes was innovated，it adopted a new double crescent curved spokes, on thebasis of finite element simulation and with the largest amount of deformation as theobjective function, the size of the elastic components were optimized. Throughrelevant experiments, various static characteristics of this torque sensor wereresearched and analyzed. The main research content is summarized as follows:First, on the basis of grasping the characteristics of various types of fiber gratingsensors, and combined it with existing torque measurement method, it was proposedthat to measure torques with optical fiber grating had broad application prospects, theFBG strain measurement principle was deeply analyzed, the feasibility of applyingFBG into torque measurement was determined.Second, it analyzed the force of the elastic element and established the FBGtorque sensor module. A finite element simulation analysis for the elastic structureswas carried. And the shape and size of elastic structures were determined based on thesimulation results.Third, according to the need of the torque experimental measurement, designed atest system for FBG torque measurement. The key of this design is the pure torqueloading device and the signal processing and displaying system.Fourth, based on the multiple experiments of FBG torque measurement,hysteresis errors, linearity, repeatability errors, temperature sensitivity of FBG torquesensor were calculated; Compared the experimental data of spokes to axis, the strainsensitivity of this new spokes structure was improved nearly2times.