A Study of the Underactuated Mechanisms with Compliance

Abstract

In this paper, we introduce a task-based method for designing underactuated gripper mechanisms in which actuators are linked with the joints via elastic elements. The inclusion of elastic elements in the kinematic structure allows better compliance of gripper fingers to the shape of the grasped object because in this case the elastic elements work as convertors of the displacement of the actuators. In the proposed research we focus on the design of multi-joint grippers that contain fewer independent actuators than the joints and the geometry dedicated for specific tasks. In order to minimize the complexity of the gripper mechanism while keeping its efficiency, we analyzed the joint motions of the mechanisms during the execution of each task and investigated the level of participation of each joint for every task. The results of this study can be used for systematic design of underactuated mechanisms and for the synthesis of dedicated underactuated mechanisms that can operate in a low dimensional coordinate space.