Lu Guan, Fu Shiwen, Zhu Tianyu, Xu Yiming
School of Mechanical Engineering, Nantong University, Nantong 226019, China.
School of Electrical Engineering, Nantong University, Nantong 226019, China.
Sensors (Basel). 2023 Aug 3;23(15):6897. doi: 10.3390/s23156897.
Aiming at the problems of lateral force interference and non-uniform strain of robot fingers in the process of pressure tactile sensing, a flexible tactile sensor with a square hole structure based on fiber Bragg grating (FBG) is proposed in this paper. Firstly, the optimal embedding depth of the FBG in the sensor matrix model was determined by finite element simulation. Secondly, according to the size of the finger knuckle and the simulation analysis based on the pressure tactile sensor element for the robot finger, the square hole structure was designed, and the overall dimensions of the sensing element and size of the square hole were determined. Thirdly, the FBG was embedded in the polydimethylsiloxane (PDMS) elastic matrix to make a sensor model, and the tactile sensor was fabricated. Finally, the FBG pressure tactile sensing system platform was built by using optical fiber sensing technology, and the experiment of the FBG tactile sensor was completed through the sensing system platform. Experimental results show that the tactile sensor designed in this paper has good repeatability and creep resistance. The sensitivity is 8.85 pm/N, and the resolution is 0.2 N. The loading sensitivity based on the robot finger is 27.3 pm/N, the goodness of fit is 0.996, and the average value of interference in the sensing process is 7.63%, which is lower than the solid structure sensor. These results verify that the sensor can effectively reduce the lateral force interference and solve the problem of non-uniform strain and has high fit with fingers, which has a certain application value for the research of robot pressure tactile intelligent perception.
针对机器人手指在压力触觉感知过程中存在的侧向力干扰和应变不均匀问题，本文提出了一种基于光纤布拉格光栅（FBG）的具有方孔结构的柔性触觉传感器。首先，通过有限元模拟确定了FBG在传感器基体模型中的最佳嵌入深度。其次，根据手指关节尺寸并基于机器人手指压力触觉传感器元件进行模拟分析，设计了方孔结构，确定了传感元件的整体尺寸和方孔尺寸。第三，将FBG嵌入聚二甲基硅氧烷（PDMS）弹性基体中制成传感器模型，并制作了触觉传感器。最后，利用光纤传感技术搭建了FBG压力触觉传感系统平台，通过该传感系统平台完成了FBG触觉传感器的实验。实验结果表明，本文设计的触觉传感器具有良好的重复性和抗蠕变性。灵敏度为8.85 pm/N，分辨率为0.2 N。基于机器人手指的加载灵敏度为27.3 pm/N，拟合优度为0.996，传感过程中的干扰平均值为7.63%，低于实心结构传感器。这些结果验证了该传感器能有效降低侧向力干扰，解决应变不均匀问题，与手指具有高度贴合性，对机器人压力触觉智能感知研究具有一定的应用价值。
