Evaluation of Sensitivity of Capacitive Tactile Sensors with Different Materials

It is important to adjust the gripping force based on tactile data for ensuring successful and safe gripping in a robot's grasping process. This research aims to evaluate the performance of capacitive tactile sensors developed by Beijing Tashan Technology Co. Ltd., which have potential to be used for robot-assisted electrical capacitance tomography (ECT). There are two types of sensor structures: TS-E-1 with a multi-sensing correlation array and TS-E-2 with a multi-sensing independent array. These sensors are designed for use in robotic grippers and hands and capable for measuring three-dimensional (3D) force. The analysis in this work is focused on how the sensors perform when they come into contact with different materials, including metal, cotton, plastic, aluminium, rubber and clay. The experiment aims to identify the self-capacitance of 3D force. The percentage change in capacitance in response to the applied normal force is measured and analysed to figure out the sensitivity of each sensor with different materials and force ranges. From the experimental results, it can be seen that the sensitivity of the two sensors changes dramatically with different materials and in different measurement range, from 8.97%/N to 108.31%/N. The obtained data would help application of the sensors in robot grippers to handle various objects of different materials.