A flexible three-axial capacitive tactile sensor with multilayered dielectric for artificial skin applications

In this paper, a new flexible three-axial force sensor was designed and investigated, which was composed of four capacitors, and the mechanism was based on the capacitance change induced by an applying three-axial force. For the configuration of the electrodes, four sensing electrodes and a public electrode were in the same plane, which was based on fringe effect theory. Different from the traditional dielectric layer with single material, this multilayered dielectric consisted of both the air gap and polydimethylsiloxane. The structure of the multilayered dielectric changed under the external/applied force, leading to variation of dielectric constant ε, which caused the capacitance change. Measurement results showed that the full-scale range of detectable force was around 0–10 N for all three axes. The average sensitivities of the force sensor units were 0.0095, 0.0053, and 0.0060 N−1 for the normal, X-axis, and Y-axis shear forces, and more test proved its high potential for application in skin-like sensing field.