Grasping Fingers PDF Download

Excerpt from On the Stability of Grasping: Three Fingers and a Planar Polygon The problem of grasp planning is often approached with tacit assumptions that the object to be grasped is perfectly known, and that the end-effector or hand can be positioned with perfect control of force and location of every element in contact with the object. In many robotic applications, however, only a rough idea of object shape and location may be available, e. G. Provided by a vision system. It is shown in this paper that uncertain information can be sufficient to ensure successful grasping because an object tends to move towards a more stable configuration under certain grasping conditions. This behavior can be exploited in procedures for initial object acquisition or for pick-and-place operations, since the identity and/or orientation of the grasped object can be sensed after acquisition and subsequent robot motion appropriately adjusted. In this paper issues involved in the stable approach to a grasp are investigated theoretically. The problem is solved entirely for a triangle constrained to move in a plane in contact with two fixed point fingers when the effects of mass and friction are ignored. The motion of the triangle is given as well as a description of paths which the moving finger may follow which result in an equilibrium grip. The grasping process is found to be quite stable, and remains stable more generally: cases are considered in which fingers are not points, mass and friction are present, and more general objects are grasped. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.