Equilibrium conditions of a rigid object grasped by elastic rolling contacts

Abstract

This work refers to a planar system of two spherical elastic fingertips grasping a rigid polygonal object under rolling contact constraints at equilibrium. A contact motion model is proposed for elastic-rolling fingertips based on previously reported experimental findings on the rolling distance for a variety of soft materials. The equilibrium conditions are derived from the system dynamics and depend on the deformation and on the kind of elastic material with regard to the fingertip's rolling distance characteristics. Equilibrium conditions of the three contacted bodies (elastic fingertips-object) show that in general no-collinear interaction forces act on the object's surface and they correspond to the equilibrium of an "internal object" hold by two point contacts with friction.