Abstract: Flexible grippers,with their ability to conform to various shapes,offer significant advantages over rigid grippers,particularly when handling irregularly shaped or delicate objects. However,traditional flexible grippers often struggle with limited load capacity due to material and structural constraints,making them less effective for certain applications. A novel design for a variable stiffness flexible mechanical finger was introduced,based on the principle of granular body obstruction. This design incorporates a granular interference layer,which significantly enhances the stiffness and load capacity of the finger through active particle interaction.Unlike conventional pneumatic flexible grippers,this design allows for precise control of the finger′s bending by adjusting air pressure,optimizing its fit around irregular objects. Simultaneously,the stiffness of the finger can be fine-tuned by controlling the vacuum pressure within the granular interference layer. As the vacuum pressure increases,the walls of the compartment compress the particles more tightly,resulting in greater stiffness and enhanced load-bearing capacity.This active particle interference approach offers a key advantage over passive systems, the ability to adjust the finger′s stiffness independently of its bending angle. Moreover,as the bending angle increases,the range of stiffness adjustment also expands. Both theoretical analysis and experimental results demonstrate that this variable stiffness flexible finger,utilizing vacuum-controlled granular obstruction,effectively allows for independent control of bending angle and stiffness,enabling the flexible gripper to perform a wider array of robotic grasping tasks.

Key words: flexible gripper, variable stiffness, vacuum particle jamming, fiber reinforcement, decoupled control