Low-Patching-Error Fiber Bragg Grating Multi-Dimensional Force Sensor

In order to avoid the difficulties caused by patching-errors in fiber Bragg grating multi-dimensional force sensors, this paper applies equal strength beam structure to a crossbeam elastic element, designs and implements an improved fiber Bragg grating multi-dimensional force sensor and constructs a calibration testing system to load and test the sensor. The results show that the sensitivity change rate of the improved elastic body is significantly better than that of the traditional crossbeam elastic element. The sensitivity change rate in the X or Y directions is only about 11% of the traditional crossbeam, and the z-direction is only about 35% of that of the traditional crossbeam, greatly reducing the requirement for the accuracy of sensitive component patching. The repeatability and the hysteresis of the FBG three-dimensional force sensor are better than 1% of the full scale (200 N). The measurement error of the improved sensor in the X direction is 0.27 N, which is lower than the 0.9 N of the traditional crossbeam sensor. In the Z direction, the measurement error of the improved sensor is 0.62 N, significantly lower than the 5.73 N of the traditional crossbeam. In summary, the measurement accuracy of the FBG three-dimensional force sensor based on the improved elastic element has been significantly improved. The work presented in this article can also be applied to other forms of multi-dimensional force sensors, providing important technical references for the mass production and performance improvement of multi-dimensional force sensors, and has significant engineering implications.