Abstract
Formulation of a mathematical model expressing motion of a pair of robot fingers with hemi-spherical ends grasping a 3-D rigid object with parallel and flat side surfaces is presented. By referring to the fact that human grasp in precision and in a dynamic and stable manner is realized by opposable forces between the thumb and another finger (index or middle finger), a simple control signal is proposed and shown to realize stable grasping in a dynamic sense without using object information or external sensing. Stability of grasping with force/torque balance is analyzed on the basis of a new concept named “stability on a manifold”.
