用于假手指尖的光纤光栅触觉力传感器研究

针对现有假手触觉测量常用的薄膜压力传感器精度不佳、线性度差、迟滞性高等问题,研究了一种可安装于假手指尖的光纤布拉格光栅触觉力传感器。首先,通过传感单元的微小化结构设计,可以将施加的外力转化为光纤承受的轴向力;进而,通过有限元对传感器结构参数进行优化,提高了光纤光栅对于压力的灵敏度;然后,围绕假手指尖应用的需求,制作了这种光纤布拉格光栅触觉力传感器;最后,对该传感器进行了性能标定、对比分析和应用抓取3个实验分析,实验结果表明:该传感器压力灵敏度为0.103 8 nm/N,线性度R~2为0.998,重复性误差为1.32%和迟滞性误差为2.19%;与现有的薄膜压力传感器对比,该传感器的线性度和重复度都更高,迟滞性更低。

Research on the tactile force sensor of prosthetic hand finger based on fiber Bragg grating

The thin-film pressure sensor in prosthetic tactile measurement has problems of low accuracy, poor linearity and high hysteresis. To address these issues, a tactile sensor based on the fiber Bragg grating (FBG) is studied. It can be easily installed on the fingertip. Firstly, a sensing unit is designed to convert the external force into an axial one needed by the FBG. Secondly, the finite element simulation is utilized to optimize the structure of the sensing unit. In this way, the sensitivity of pressure measurement is improved. Finally, the FBG tactile sensor is prepared and stuck to the prosthetic fingertip. Experiments on performance calibration, comparative analysis, and grasping application are carried out. Results show, for the FBG tactile sensor, the sensitivity is 0. 103 8 nm/ N, the linearity R 2 is 0. 998, the repeatability error is 1. 32% , and the hysteresis error is 2. 19% . Compared with the thin-film pressure sensor, the designed FBG sensor has advantages of linearity, stable repeatability, and hysteresis.