Simple Fabrication of Highly Sensitive Tactile Sensing Array Inlaid an Enhanced Porous Dielectric Layer for Robotic Manipulation

Abstract

Highly sensitive flexible tactile sensors with synergistic normal and shear force perception are urgently required for possible grasping, lifting, and other in-hand manipulations of robotic hands. Here, a capacitive 3-D force tactile sensing array inlaid an enhanced porous dielectric layer was presented. The micropores were formed through vacuum-assisted infiltration of polydimethylsiloxane (PDMS) solution applying perfluorotributylamine (C12F27N) as sacrificial solvent, meanwhile, using sugar particles mixed up with PDMS-C12F27N emulsion to create extra macropores. The surface of the sensing array consisted of numbers of pen-cap-like bumps for reliable traction of objects. When normal or shear forces were applied on the surface, the contacted bumps were compressed or declined. The deflections of bumps resulted in possible capacitance variations, which were corresponded to the applied normal and shear forces. Compared with capacitive sensors inlaid an unpatterned solid dielectric layer, the developed sensing array experimentally displayed a high elasticity, a large sensing pressure range (over 250 kPa for normal pressure and over 60 kPa for shear pressures), a high sensitivity (1.63%/kPa and 1.61%/kPa for normal and shear pressure, respectively), a good repeatability, and a good structural stability and durability. Finger attached tests validated the proposed tactile sensing array having great potential for all kinds of robotics and prosthetic hand applications.