A Novel Force Sensor Based on Optical Fibers Used for Semicircular Flexure Beam Unit

In this article, a novel force sensor is designed based on the optical fiber bending loss theory utilizing a structure with periodically corrugated semicircular flexure beam units. The fiber bending loss theory composed of the pure bending loss and the transition loss is related to the curvature radius according to the theoretical analysis. Both the optical working modes and the mechanical properties of the designed sensor are discussed. The output voltage attenuation of different curvature radii is tested and the curvature radius of 6 mm is selected for further experiment. The actual sensing results are acquired using a commercial force sensor. The result shows that the nonlinear errors of the forward and the reverse force applying process are 11.82% and 17.86%, respectively. The sensitivity is 13 mV/N and the precision is 160 mN. The experiment under different temperatures ensures the temperature-insensitive characteristics of the sensor.