Design and Experimental Research on Small-Structures of Tactile Sensor Array Unit Based on Fiber Bragg Grating

For the problem that the accuracy of the traditional the fiber Bragg grating (FBG) tactile sensor array unit is relatively low, which is caused by the lateral force. In this paper, we focused study on the small-structures of a single node of the array sensing unit, and designed the small-structures that can convert the exerted external force to the fiber axis tensile deformation. After using the finite-element analysis software to simulate and analyze the four kinds of small-structures, two kinds of small-structures were chosen for further research. In order to verify the feasibility of the chosen small-structures, a series of system performance tests were conducted. For the structure containing the arched bridge, the natural frequency is 17 Hz and the sensitivity is 0.38 nm/N. For the structure which contains a small hole and the FBGs locating in bottom position, the natural frequency is about 18 Hz and the sensitivity is 0.29 nm/N. The experimental results match the simulation results to demonstrate the good performance (high sensitivity and good linearity) of both the small-structures. In the performance tests for the FBG tactile sensor array unit based on one kind of the designed small-structure, the average positioning error is 0.057 cm(2) and the average sensing force value error is 0.038 N. The array sensing unit has relatively high accuracy, which is expected to be used in the actual project.