Experimental Study of Torque Measurement Based On FBG

This paper discusses a method of torque measurement based on the fiber Bragg grating (FBG) sensor, and introduces the FBG’s application for torque measurement in a rotating shaft with four same planes. With external torsion applied to the shaft, the data obtained by finite element analysis verified the rationality, reliability and strain sensitivity of this design. One end of the shaft is fixed, while the other is connected to a device providing a particular value of torsion with a full scale of 100 Nm. Two parallel gratings FBG1 and FBG2 are bonded on the purposefully machined planes on the shaft symmetrically. Considering the differential-mode wavelength of the dual-grating torsion sensor, the result shows a low temperature sensitivity and a high torsion sensitivity. The sensitivity of the torque measurement system is 14.5 pm/Nm, and has a high linearity and linear correlation.