A Novel Flexible Centralized Force Sensor Based on Tri‐Axis Force Refactoring Method for Arbitrary Force Components Measurement

Abstract

Flexible force sensors have been widely applied in robotics for object exploring, remote controlling, and human–machine interactions. The tri‐axis force sensors for accurate measurement of normal and shear forces are generally in urgent demand. Most tri‐axis force sensors rely on signal analyzation between multiple elements to achieve force components, which may need numerous leading wires and limit the force angular sensing performance. Herein, a novel flexible centralized force sensor is developed based on a novel tri‐axis force refactoring method. Normal force is detected by the central parallel‐plates capacitor, and both the angle and amplitude of shear force can be extracted through the resistance changes. The normal force performance is characterized with a sensitivity of 0.057 N−1 and a detection range of 0–12 N, and the effective detection range of shear force is about 0.5–0.67 N. The minimum distinguished shear angle difference is about 7.3°, which can be further improved by increasing the sensing material's resistivity. Then, robotic grasping tests are performed and show that the sensor can accurately measure the normal and shear forces and applied shear force angle, which indicates its promising applications in potential robotic manipulation and interactions.