Polymer tactile sensing array with a unit cell of multiple capacitors for three-axis contact force image construction

In this work, we have implemented a three-axis capacitive tactile sensor using PDMS as a base material. The sensor measures the deformation of PDMS membrane by contact force applied to each cell. In each tactile cell there are four capacitors to decompose the contact force into normal and shear components. In order to measure the shear force, a large bump and a pillar structure have been implemented at the center of the tactile cell structure. The sensor has been realized in an 8 x 8 array of tactile cells and each tactile cell shows respective responses in all three directions. The full scale range of detectable force has been measured less than 10 mN.