Stiffness analysis of multi-fingered robot hands

Although additional stiffness induced from configuration change is an important issue, in the case of multi-fingered hand, there are very few discussions about this problem especially, at the joint stiffness level. In order to analyze and control the multi-fingered robot hands this problem should be considered because it may cause the instability of a grasp. In this paper the stiffness of a grasp was analyzed based on the Generalized Virtual Stiffness Model. Considering that the normal and lateral stiffness of the finger usually are not decoupled due to kinematics and mechanical design, GVS is formulated as coupled virtual springs. We related GVS to the effective fingertip stiffness including the additional stiffness at the joint space. Based on the grasp stiffness formulation, simulations were carried out especially in the viewpoint of the grasp stability.