Abstract
This paper presents a fast method of evaluating grasp stability when a multi-fingered hand grasps objects. Different from previous methods, we consider approximating the friction cone by using a few ellipsoids. By using this method, the total force/moment set applied to the grasped object can be obtained by a common set of multiple ellipsoids. This method is not conservative but effective since approximated force closure is tested by simply calculating the inequalities of quadratic form. Moreover, by using the ellipsoidal approximation, we propose an easy method of evaluating the grasp stability. We show that the grasp stability can be easily calculated by using simple equations. The effectiveness of the proposed method is verified by several numerical examples where we show that the proposed method has practical accuracy for real applications and evaluates the grasp stability much faster than conventional methods.
