Torsional Stiffnesses of the Soft Contact of a Soft-Robotic-Finger

This paper investigates the equivalent contour representation of the soft contact, proposes torsional stiffness coefficients relating the contact contour to a soft-robotic-finger contact and develops the finite elastic elements of the soft finger. The contact is modeled between a grasped object and a soft fingertip as a number of contours with a set of equivalent elastic contact points arranged on each contour. The stiffness matrix model is presented and related to the torsional stiffness coefficients. The paper further reveals the effect of the robotic finger stiffness on the stiffness coefficients by modeling the finger with a finite number of elastic elements arranged serially. The couples which arise from the elastic elements give translational and torsional stiffness characteristics of the soft contact. This presents a way of measuring soft contact stiffness. In particular, the torsional stiffness is investigated with its variance with the contours. A case study is presented at the end.