A Rotational Tri-fingered Gripper for stable Adaptable Grasping

Abstract

Conventionally, researchers focus on the structure of robotic fingers to enhance robotic grasping. In this study, we present a method to improve the performance of robotic end effector by adding one rotating DOF at the base of each robotic finger. Various type of existed robotic finger can conveniently use this rotating base through a simple connector. With those rotating DOFs, each finger can rotate individually around the concentric gear palm. As a result, the grasping volume of robotic end effector is extremely enlarged compared to those fixed finger base counterpart. Rotating each robotic finger to the desired position helps the end effector taking an adaptive grasping manner to various objects. This dramatically enlarges the grasping adaptability without any change of the robotic finger structure. If rotating all fingers simultaneously, the robotic end effector can provide a redundant DOF for manipulator. The extra DOF function as a rotating wrist helps the robotic end effector keep grasping stable in space and provides more trajectory solution for manipulator. The design concept and function realization of rotating DOF are discussed in the paper. The proposed rotation actuation and control are presented. Dedicated experiments are induced to validate our proposed mechanism. The grasping performance of a prototype rotational tri-fingered gripper with cable driven underactuated fingers is presented, which prove the rotating DOF at the finger base brings larger working space and better-grasping adaptability