LBH gripper: Linkage-belt based hybrid adaptive gripper design for dish collecting robots

Abstract

Recent developments in robot technology have led to the expansion of robot automation in various service fields. In this study, we developed a gripper for a plate retrieval robot for restaurant environments. Plate retrieval grippers are challenged by the variety of types and sizes of plates to be collected. Therefore, a gripper that can adapt to a variety of plate shapes and sizes is needed. To address these issues, we propose a Linkage-Belt Hybrid (LBH) gripper that combines a linkage structure and a soft gripper. The design of the LBH gripper was verified through structural analysis through simulation, and its performance was experimentally evaluated. Results show that the LBH gripper outperforms traditional bar-type, linkage-adaptive, and soft grippers. In an experiment involving randomly grasping 23 objects, the LBH gripper demonstrated the ability to grasp the highest number of objects, with only two objects experiencing a 30% failure rate. Additionally, the gripper's payload is verified to be 10kg for bowls and 6kg for plates. In the safe release test, it was confirmed that it showed a significantly lower impact amount compared to the bar-type gripper. In addition, by operating the manipulator after gripping the dish, the gripping stability and the possibility of performing non-grabbing movements were confirmed, confirming that the LBH Gripper is suitable for the target dish collection task. These findings pave the way for the development of new connected belt hybrid grippers capable of gripping a variety of objects.