A Soft Robotic Gripper with Variable Grasping Force Based on Jamming Phenomenon

This paper presents a dual-chamber soft robotic gripper based on the jamming principle, capable of adjustable grasping force. The proposed design integrates an inner pneumatic actuation chamber and an outer granular jamming layer, enabling tunable stiffness through vacuum control. This design allows the gripper to adapt its stiffness based on varying vacuum pressure, improving both flexibility and force control. By combining pneumatic actuation with granular jamming, the gripper achieves large-range deformation while maintaining precise control over its mechanical properties. Experiments were conducted to measure the force-displacement characteristics under various negative pressures. Results showed that the gripper's stiffness increased from 0.10 N/mm to 0.32 N/mm as the vacuum pressure increased, demonstrating its ability to adaptively regulate grasping force. The findings confirm that the proposed gripper outperforms traditional soft actuators in flexibility, safety, and adaptability, providing a foundation for future closed-loop control and intelligent manipulation in soft robotics.