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This paper introduces a general method for predicting the stability of grasps obtained by articulated mechanical hands. Two contact models are considered: point contact with friction, and a distributed form called the "soft finger contact". The method is applicable to a large class of statically indeterminate, as well as determinate, cases. Results from several examples are included.

A method is introduced for locating stable grasps with articulated mechanical hands. A metric called the grasp goal function represents the `distance' to an unstable grasp for a given position, external load, and set of joint torques of the gripper. The process of locating a stable grasp is treated as an optimization problem for which the most stable grasp is found by maximizing the grasp goal function. Physical constraints, such as torque or motion limitations, are accounted for by the incorporation of potential functions in the objective function. Two-dimensional and three-dimensional simulations were undertaken for which objects were represented as polygons/polyhedral and gripper elements as ellipses/ellipsoids.