Five-fold sensitivity enhancement in a capacitive tactile sensor by reducing material and structural rigidity

Abstract

© 2019 Elsevier B.V. We significantly enhanced the detection sensitivity of a capacitive tactile sensor (CTS) in this work by lowering the Young's modulus of the elastomer that separated the two electrodes of a capacitor. Compared with a typical CTS, the reduced material and structural rigidity improved the detection sensitivity to the normal force by 19.7%, 50.4%, 147.1%, and 217.6% when the Young's modulus of the elastomer was reduced by 32.8%, 60.8%, 84.2%, and 87.0%, respectively. Although the sensitivity to shear force varied with angle, the enhancement exhibited an increasing trend as Young's modulus of the elastomer was reduced, yielding a maximum average 539.5% sensitivity improvement. In addition to the observed enhancements, the sensitivity to normal and shear force exhibited an exponentiation relationship with the reduction in Young's modulus of the elastomer. Furthermore, the shear angle remained resolvable with the CTS and its accuracy was unaltered, regardless of Young's modulus of the elastomer. Theoretical designs, numerical simulations, experimental verifications, and analytical discussions are presented in this work, which illustrate the effectiveness of the proposed method.