Grasp Stiffness Matrix for Soft Finger Contact Model in Robotic Applications

Abstract

Abstract This paper proposes a practical and analytical model for soft finger grasp. It presents a contact stiffness matrix by applying congruence transformation and mapping stiffnesses from a line spring model onto translational and rotational stiffnesses. The contact that is realised in this paper is in the form of a patch contact with evenly distributed finite number of equivalent point contacts. An analytical approach is hence proposed based on line springs and screw representation of the frictional elastic point contacts that provides a direct correlation between the equivalent point contact and soft finger contact of a rigid object and gives a procedure to complete the analysis. The grasp achieved with the analysis provides both translational and rotational restraint. The approach and its use for finite manipulation are supported by a case study.