A novel low-cost capacitive tactile sensor

A novel capacitive tactile sensor with slip detection capabilities is reported in this paper. The proposed sensor consists of a conductive layer, an insulating layer and a silicone dome structure. This design is easy to construct and can be realized using less expensive components compared to previously reported capacitive tactile sensors. Each sensing unit in the conductive layer consists of four electrodes. Application of external force leads to deformation of silicone layer which leads to change in capacitance of electrodes. This change in capacitance from each electrode to nearby ground surface of the conductive layer is measured to compute the force and detect the slip. The relationship between capacitance and force is modeled using a polynomial function of suitable order which is then used to estimate the force applied. Finite element analysis was used to study the behavior of the proposed sensor. A prototype sensor was fabricated and tested, which was found to detect slip and estimate the force with good accuracy and excellent repeatability. The prototype´s characteristics are well in agreement with the simulation results.