A flexible capacitive tactile sensor for robot skin

This paper presents a flexible capacitive sensor array which can be attached on robot arm for tactile force measurement. We designed and fabricated three types of sensor array in different dimensions. The sensor array with 4×4 tactile units is made of copper and PDMS based on PET substrate. The static characteristics are performed and it is found that the sensor array with 3×3 mm
²
unit size is the optimal one among these three types. The sensitivity of the optimal sensing unit is 0.84%/N in a force range of 0-3.7 N. In order to achieve the controlling of robot motion, we developed a capacitance detection circuit to transfer the capacitance change to voltage variation. Furthermore, a tactile feedback and signal acquisition system is built up for the application of robotic obstacle avoidance.