Development and Characterization of Vertically Stacked Tactile Sensor With Hollow Structure

In this study, a capacitive tactile sensor (CTS) that simultaneously supports high detection sensitivity and high spatial resolution with a hollow dielectric structure is reported. By vertically stacking two capacitors with intentionally misaligned electrodes among the capacitors, not only the normal and shear force but also the shear angle can be detected. A comprehensive fabrication procedure that advanced the existing solutions was developed in addition to its theoretical design and numerical evaluation. Results indicated that the proposed hollow CTS outperformed the referential solid CTS in detection sensitivity for both the normal (on average 31.660 pF/N under 0.5 N) and shear force (at least 5.61 times enhancement under 1.5 N) applications. The results also proved comparable shear angle detection accuracy to previously existing CTS. Additionally, the periodical variation of sensitivity enhancement along the shear angle was found and analyzed for the first time, which provided design guidance for the arrangement of the electrodes in the CTS regardless of its dielectric structure.