Neighborhood equilibrium grasp for multiple objects

Discusses the neighborhood equilibrium grasp for multiple objects. Assuming rolling contact at each contact point, we first define rolling based redundancy which means that the grasped objects have degrees of freedom through the rolling motion even if the finger posture is fixed. For the grasp having rolling based redundancy, we say that there exists the neighborhood equilibrium if the system can be shifted to another equilibrium state close to the original one even when the current equilibrium is broken. We evaluate the robustness of the equilibrium state by utilizing the rotating angle, where the system loses the neighborhood equilibrium. We show several numerical examples to verify our idea