Grasp impedance: examples of finger's targeted impedance

Abstract

Two examples of formulating the targeted impedance of fingers of a mechanical hand are presented. A unified model of targeted impedance, based on the physical equivalence postulate of the closed-loop dynamics behavior of fingers, is used. Based on this postulate, the parameters of the targeted impedance can be selected such that the dynamic behavior of the closed-loop system satisfies specific task requirements. The first example is a formulation of the targeted impedance based on the object desired grasp stiffness properties at the point of interaction with the environment. The second example is a formulation of the targeted impedance for the case where the grasped object has some oscillatory motion, such that the oscillation of the object is minimized about some nominal equilibrium point. A method of obtaining the finger configuration based on the static relationship of the targeted impedance is also presented.<>