Elastic Force Models of Hemispherical Soft Fingertip with Geometric and Material Nonlinearities for Fine Soft-fingered Manipulation

Abstract

This study focuses on the derivation of elastic force models of a hemispherical soft fingertip and reveals the existence of a local minimum of elastic potential energy (LMEE) induced by the deformation of the fingertip. The proposed model can be written in a straightforward equation when the geometric nonlinearity of the fingertip is applied in the derivation process, which is suitable for analyzing the stability of robotic handling system with soft fingertips. We also show complete elastic force and potential energy equations by incorporating the material nonlinearity into the derived model. Furthermore, we compare our models with the Hertzian contact theory that is applicable to the practical usage for the strength design of a lot of machines. Finally, we demonstrate the validity of our models by comparing simulation results and experimental results.