Hand–Object Interaction Modeling for Precision Grasp by Multi-fingered Hands

This paper presents modeling of interaction between a multi-fingered hand and object in precision grasp. The analysis is useful in planning of precision grasps with dexterous multi-fingered hand and can be extended to the study of precision manipulation by robotic hands. We develop the grasp matrix given the coordinates of the contact points and normal direction at the contact points. The grasp matrix computes the resultant force on the object given the contact forces. We also develop the hand Jacobian for the multi-fingered hand that maps the joint torques to the fingertip forces. We present the modeling for a three-fingered hand and an arbitrarily shaped object. We present the condition for force closure and the method to evaluate it for grasping by a multi-fingered hand. We also present the additional conditions required for grasp by underactuated hand. This work extends our previous work in which we considered grasping of cylindrical objects. We extend the work to arbitrarily shaped objects in the present work.