EXPERIMENTAL VALIDATION OF AN OPTIMIZATION FORMULATION OF THE HUMAN GRASPING QUALITY SENSE

An experimental procedure that evaluates the quality of a grasp is dev eloped. In this procedure human subjects grasp a rigid object that is subjected to an external load. Three formulations that capture the sen se of grasping quality through the energy level stored in the gripper, maximum value of the applied finger forces, and through the distribut ion of the grasping forces are considered. The applied finger forces a re measured and the quality values of the grasp based on these three d ifferent formulations are computed. These grasping quality values are compared with numerical human assessments, that are obtained via a psy chophysical magnitude estimation method. We derive an augmented weight ed functional that combines these three formulations, and show that it exhibits a high correlation with human quality assessment. Our result s demonstrate that the most dominant mechanism that characterizes the quality of a rigid body grasp is the uniformity level of the contact f orces. (C) 1997 John Wiley & Sons, Inc.