A Soft Robotic Gripper With an Active Palm and Reconfigurable Fingers for Fully Dexterous In-Hand Manipulation

Abstract

This study is focused on developing a new dexterous soft robotic gripper with three fingers and an active palm capable of performing in-hand manipulation purposes. This innovative design meets all the dexterous manipulation requirements without any increase in mechanical complexity. In each finger, the bending position can be modified and controlled by moving a stiff rod inserted inside the center hole of the finger. In this way, the effective length of the manipulation can be changed. As a result, these reconfigurable fingers provide a more accessible workspace than conventional soft grippers. Besides, a large diversity of the finger's shape configurations results in more dexterity and in-hand manipulation capability. Workspace analysis is accomplished to characterize the advantages of the proposed design. The effectiveness of this soft robotic gripper is validated by different in-hand manipulation experimental tests, including rotation, regrasping, and rolling. The results suggest a promising solution to bridge the design gap between hard and soft robots for dexterous manipulation tasks. The hybrid design carries advantages of these two classes, such as reconfigurability, position, and shape control from hard robots, with large degrees of freedom (DOFs), complex deformations, and lightweight from soft robots. Like human manipulation, the palm plays a major role in stable grasping, especially for enhancing the in-hand manipulation capability. Therefore, we also investigate two types of vacuum palms (suction cup and granular particles) to guarantee a wide range of object manipulation tasks that cannot be completely performed by previously suggested soft grippers.