Design and Control of a Hydraulic Driven Robotic Gripper

Abstract

The robots with robotic grippers can take the place of human to carry objects and use tools efficiently in different situations. This paper presents a novel hydraulic driven robotic gripper named the WLRG-I (the first generation of Wheel-legged robot gripper) which bears large load and has strong robustness. The WLRG-I is installed on the wheel-legged humanoid robot arm to make the WLR-III (the third generation of Wheel-legged robot) have the capability of grasping daily tools and fulfilling special operation tasks in harsh environments. This paper focuses on the design of gripper transmission structure, kinematics and statics. Firstly, the linkage mechanism is proposed according to the design goal. Then, the kinematics and statics of the gripper are studied, and a structural model is established. In addition, PID controller is used to control the position of the gripper with angle feedback. Finally, position tracking and load experiments are completed to verified the accuracy of the control. The gripper can grasp objects of 20kg with 2.15kg dead weight. To the authors’ best knowledge, robot grippers with such a high load-to-weight ratio are very rare.