Modeling and experimental studies of capacitive pressure sensors with microstructured dielectric layers

Yanmin Zhou,Yafei Wang,Zhipeng Wang,Zhe Yan,Bin He

doi:10.1177/0020294019833071

Yanmin Zhou, Yafei Wang + Show 3 more

Open Access

https://doi.org/10.1177/0020294019833071

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Abstract

Electronic skin (e-skin) has shown great application prospects in many fields due to its multiple advantages. Previous studies have illustrated that the structure with a dielectric layer sandwiched between two electrodes had good pressure-sensing abilities, and microstructures in the dielectric layer could improve the sensitivity. In this paper, we proposed mechanical models of e-skin sensing unit with different microstructures (flat, trapezoidal, half-cylinder, and pyramids) in the dielectric layer. Then, we performed finite element method simulations and experiments to validate the model. Finally, we demonstrated its application as the pressure-sensing unit for human hands, showing its great potentials in sensors of artificial prosthesis or soft robots in the future.

Highlights

Skin is an important media for humans to perceive the environment
Artificial prostheses and data gloves applied to Virtual Reality (VR) systems have been able to mimic certain mechanical and biological properties of the human body[2,3,4] and achieve the sensing ability of the skin to some extent
E-skin, as a new type of sensor based on flexible materials, has the advantages of lightweight, strong environmental adaptability, simple structure, and excellent biocompatibility.[5]. These advantages can be well applied in the design and fabrication of auxiliary sensing system of artificial prosthetics[6] as well as other health care applications.[7]

Summary

Introduction

Skin is an important media for humans to perceive the environment. Its powerful sensing ability can help people to understand the shape, surface features, and contact patterns of the contact objects. By obtaining the capacitances through the parallel-plate capacitance formula C = ere0A/d (where er = 2.7 is the relative dielectric constant of PDMS,[18] e0 = 8.85 3 10212 F/m is the permittivity of free space, and C0 = 10.76 pF is the initial capacitance of the sensing unit without pressure), the pressure–capacitance relationships and pressure– relative capacitance change relationships of e-skin sensing units with different dielectric layer microstructures are shown in Figure 4(b) and (c), respectively. The pyramid microstructure increased the sensitivity of the e-skin sensing unit the most

Findings

Experiments and discussion

Conclusion