The ability of underactuated hands to grasp and hold objects

In order to calculate and measure the performance of underactuated hands to pick up and move various objects, two new performance metrics have been defined. These metrics quantify the capability to achieve stable grasp equilibrium of a range of freely moving objects (ability to grasp), and the capability to keep hold of the grasped objects while disturbing forces are applied (ability to hold). The calculations and measurements of these metrics are shown for cable-pulley driven hands.