Towards Humanlike Social Touch for Sociable Robotics and Prosthetics: Comparisons on the Compliance, Conformance and Hysteresis of Synthetic and Human Fingertip Skins

Abstract

The artificial hands for sociable robotics and prosthetics are expected to be touched by other people. Because the skin is the main interface during the contact, a need arises to duplicate humanlike characteristics for artificial skins for safety and social acceptance. Towards the goal of replicating humanlike social touch, this paper compares the skin compliance, conformance and hysteresis of typical robotic and prosthetic skin materials, such as silicone and polyurethane, with the published biomechanical behavior of the human fingertip. The objective was achieved through materials characterization, finite element (FE) modeling and validation experiments. Our initial attempt showed that the selected types of silicone and polyurethane materials did not exhibit the same qualities as the human fingertip skin. However, the methodologies described herein can be used to evaluate other materials, their possible combinations or other fingertip design configurations.

Tribology of Skin: Review and Analysis of Experimental Results for the Friction Coefficient of Human Skin

“…tactile feedback) similar to those of human skin in order to enable the dexterous handling of objects by robotic hands and prostheses [41][42][43][44][45][46]. It is known that friction governs the forces that are applied by the fingers when grasping and manipulating objects [47].…”

Soft dielectrics for capacitive sensing in robot skins: Performance of different elastomer types

“…(1), the dielectric constant, taxel area, the nominal thickness of the dielectric, and its mechanical properties are fundamental design parameters. Much work has been carried out to correlate specific robot tasks with the physical properties characterizing tactile sensors [6][7][8][9][10]. However, the analysis has been mainly focused on identifying materials whose response characteristics resemble at best that of human fingertips [11].…”

Hyperelastic Modeling of Rubber-Like Photopolymers for Additive Manufacturing Processes

“…The purpose is to test the reliability of the proposed constitutive models when designing soft pads for robotic devices such as anthropomorphic hands, prostheses and orthoses Cabibihan et al, 2009;Dollar & Howe, 2006;Tiezzi & Kao, 2006;Xydas & Kao, 1999). It is self evident that the knowledge of the constitutive behavior of the material composing the pads is fundamental in order to achieve the desired performance and to optimize the overall design.…”

“…With regard to solution controls, the element's technology is based on the Selective Reduced Integration Method (also named B method) that helps to prevent volumetric mesh locking that usually occurs in nearly incompressible models, where a purely hydrostatic pressure can be added without changing the displacement history. In such a case, the displacement field is augmented with a hydrostatic pressure field using a mixed (hybrid) formulation named Mixed U/P Formulation (Bhashyam, 2002), that allows to spawn mesh without volumetric incompressibility problems. Meshed models and dimensions are shown in Figs.…”