An adjustable gripper as a reconfigurable robot with a parallel structure

Abstract

In this paper, we propose a robot system, which combines a parallel manipulator with an adjustable gripper. The robot is able to grasp objects with different sizes and shapes without using an additional gripper. It consists of several fingers with contact elements which can be moved independently from each other to grasp the object. After grasping, adhesion forces, provided, e.g. by an electromagnet or a vacuum cup, ensure that the fingertips remain connected to the object to be manipulated. The resulting closed-loop mechanism, formed by the fingers of the robot and the object, features a kinematic structure similar to that of parallel manipulators. The Robot is now able to achieve manipulation of objects with six degrees of freedom by actuating exactly six joints. Such a parallel robot – gripper combination has many advantages over existing industrial grippers, often used for simple gripping tasks, existing mechanical hands with costly control architecture and parallel manipulators with fixed kinematic parameters.