A Two-DoF Jamming Gripper for Universal Grasping and Screwing Operation

This paper proposes a two- DoF universal gripper to realize grasping and screwing operations. The working principle is based on a jamming effect of granular materials. The gripper's core component is a silicon cup cast from a 3D-printed mold and filled with foamed polypropylene beads. Its grasping motion is driven by a linear actuator, reducing the system weight and making the gripper easier to implement than pneumatic or hydraulic structures. Besides, a rotation function is integrated into the gripper, allowing it to fulfill screwing operations. The models of the gripper's holding force are presented in this paper, and the multi-modal grasping capabilities are analyzed. A physical gripper is manufactured and tested in several grasping and screwing experiments to evaluate the proposed gripper. The results indicate that the design is effective and the gripper is versatile.