针对传统的电容式触觉传感器因存在信号耦合测量, 导致切向灵敏度远低于法向灵敏度的问题, 基于多层电容结构, 设计了一种三轴力解耦测量的高灵敏触觉传感器。传感器分为切向和法向测量单元, 切向测量单元采用对称分布的差分式指状结构保证切向高灵敏测量, 并结合超薄弹性硅胶介质, 提高切向介质层有效压缩刚度,以抑制法向信号的耦合干扰; 法向测量单元的介质层采用一种弹性稀疏网状微结构, 用于法向高灵敏测量, 并通过拓展法向接地极消除切向信号的耦合干扰。在对电容结构参数化设计的基础上, 完成触觉传感器的制备,并搭建三轴力测试系统进行测试。结果显示, 传感器的切向X, Y以及法向的测量灵敏度为0.206 pF/N, 0.251 pF/N, 0.148 pF/N; 切向X-Y以及切向-法向之间的最大静态耦合比分别为7.636%, 1.051%。本传感器实现了三轴力的解耦测量及切向、法向相同量级的高灵敏特性。

Traditional capacitive tactile sensors have much lower sensitivity in the direction of shear force than in that in the normal direction owing to the existence of coupling measurement of signals. To resolve this issue, a highly sensitive tactile sensor, with triaxial force decoupling measurements was designed based on multilayer capacitor structure. The sensor comprised of measuring units for both the shear force and normal directions. The measuring unit for the shear force direction adopted differential finger elements with symmetric distribution to achieve highly sensitive measurements. The structure of an ultra-thin elastic silicone dielectric was adopted to improve the effective compression stiffness of the shear dielectric layer, thereby restraining the coupling interference from the normal direction. The measuring unit for the normal direction useed a sparse of elastic mesh microstructure as the dielectric to achieve highly sensitive measurements. The coupling interference from the direction of the shear force was restrained by extending the normal grounding electrode. The tactile sensor was manufactured based on the parametric design of the capacitor structure. Furthermore, a triaxial force system was built to test the sensor. The test results show that the sensitivity in the shear X and Y and normal directions are 0.206 pF/N, 0.251 pF/N, and 0.148 pF/N, respectively. Additionally, the maximum static coupling ratios between the shear X and Y directions and that between the shear and normal directions are 7.636% and 1.051%, respectively. The proposed sensor achieves decoupling measurement of the triaxial force and maintains the same level of high sensitivity in the shear force and normal directions.