A flexible capacitive tactile sensor array with high scanning speed for distributed contact force measurements

This paper presents an 8×8 (=64) capacitive tactile sensor array with integrated four capacitance-digital-converter (CDC) scanning circuit for three-axis force measurement. For the structural design of the sensor array, the upper and lower electrodes generate four capacitors in one sensing unit and decompose the contact force into three-axis force components. To enhance the flexibility, a thinner PDMS bump (0.5 mm) and truncated pyramid dielectric layer with finer dimensions are utilized. To increase the scanning speed, we divide the sensor array into four regions and using four CDC circuits to simultaneously measure the capacitance changes of these regions. The sensor array is mounted onto a hand finger for grasping of a paper cup. Results showed that the sensor array can detect the distributed contact force at high scanning speed, thus could be utilized in robotic grasping applications.