Manipulation of a circular object by a pair of multi-DOF robotic fingers

This paper aims to formulate a dynamic model of a pair of dual multi-DOF robotic ringers with rigid tips grasping a circular-shaped object and proposes a new control framework for dexterous manipulation. Firstly, based on the Lagrange method and Hamilton's principle, a dynamic model of the general object-fingers setup has been described as a system of algebraic differential equations composed of ordinary differential equations governing dynamics of the fingers and the object and a set of algebraic constraints governing rigid contacts between two ringer-tips and object's surfaces. Secondly, a control algorithm for stable grasping of the object by the pair of ringers has been proposed. Thirdly, another control signal for desired orientation and position of the grasped object has been proposed and asymptotic convergence of the closed dynamics to the desired orientation and position has been analysed. The principle of linear superposition of control signals has been applied to ensure stale grasping while control desired motion. Numerical simulation results have reconfirmed the effectiveness of the proposed control law.