A 3-DIMENSIONAL CRITERION FOR THE DETERMINATION OF OPTIMAL GRIP POINTS

Multifingered grasping has aroused remarkable interest because it make s possible the manipulation of objects of different shapes and sizes. However, manipulating and picking up objects in unstructured environme nts requires accurate contact-point selection. Generally, such process es are subject to external forces which are difficult to predict and m ay change during task execution. In this paper, an optimization criter ion is proposed which is meant to select the optimal grip points in a three-dimensional problem for any number of contact points. This metho d may be applied to three-dimensional objects of any shape (curved or polygonal) and does not require that the external forces acting on the object be known. A grasp quality index is presented which has been ob tained by minimizing the grasping forces required to balance a general ized external disturbance. The optimization criterion has led to the f ormulation of a single optimization problem with non-linear constraint s. Finally, the paper presents the results obtained in searches for th e optimal grip points on some two- and three-dimensional object. Copyr ight (C) 1996 Elsevier Science Ltd.