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Contact mechanics for soft robotic fingers: modeling and experimentation

Published online by Cambridge University Press:  31 October 2012

Sadeq H. Bakhy
Affiliation:
Department of Machines and Equipments Engineering, University of Technology, Baghdad, Iraq
Shaker S. Hassan
Affiliation:
Department of Machines and Equipments Engineering, University of Technology, Baghdad, Iraq
Somer M. Nacy*
Affiliation:
Department of Manufacturing Operations Engineering, Al-Khwarizmi College of Engineering, Baghdad, Iraq
K. Dermitzakis
Affiliation:
Artificial Intelligence Laboratory, Department of Informatics, University of Zurich, Zurich, Switzerland
Alejandro Hernandez Arieta
Affiliation:
Artificial Intelligence Laboratory, Department of Informatics, University of Zurich, Zurich, Switzerland
*
*Corresponding author. E-mail: somernacy@gmail.com

Summary

Human fingers possess mechanical characteristics, which enable them to manipulate objects. In robotics, the study of soft fingertip materials for manipulation has been going on for a while; however, almost all previous researches have been carried on hemispherical shapes whereas this study concentrates on the use of hemicylindrical shapes. These shapes were found to be more resistant to elastic deformations for the same materials. The purpose of this work is to generate a modified nonlinear contact-mechanics theory for modeling soft fingertips, which is proposed as a power-law equation. The contact area of a hemicylindrical soft fingertip is proportional to the normal force raised to the power of γcy, which ranges from 0 to 1/2. Subsuming the Timoshenko and Goodier (S. P. Timoshenko and J. N. Goodier, Theory of Elasticity, 3rd ed. (McGraw-Hill, New York, 1970) pp. 414–420) linear contact theory for cylinders confirms the proposed power equation. We applied a weighted least-squares curve fitting to analyze the experimental data for different types of silicone (RTV 23, RTV 1701, and RTV 240). Our experimental results supported the proposed theoretical prediction. Results for human fingers and hemispherical soft fingers were also compared.

Type
Articles
Copyright
Copyright © Cambridge University Press 2012 

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