Flexible Centralized Tri-Axis Force Sensor based on Capacitance and Intrinsic Resistance of Bump Structure

Flexible tactile sensors have been widely applied in robotic interaction tasks. Among various tactile stimuli, multi-axis force sensing is usually significant for slippage detection and complicated manipulation. Researchers have been working on structural design of tri-axis force sensors, while many of them have complex measuring circuits and low angular sensing resolution. This work presents a novel flexible centralized tri-axis force sensor with circular bump structure. Normal force is measured by the central parallel-plates capacitor, both the shear force and angle can be extracted through the intrinsic resistance changes of the circular resistor. By adjusting material resistivity, the angular resolution of shear force can approximately reach 15° or more, which enables the detection of tri-axis force in robotic interaction tasks in the future.