Surface-Conforming Modular Jamming Pads for Enhanced Contact and Friction

Abstract

Granular jamming has been widely explored for adaptive robotic grasping, but conventional designs typically rely on single spherical jamming structures that limit contact distribution and modularity. This paper presents a flexure-based robotic gripper integrating modular square-shaped granular jamming pads as distributed adaptive contact interfaces. The design combines structural compliance from paired-Crossed Flexural Hinges (p-CFH) with material compliance from granular jamming, enabling passive surface conformity while improving frictional coupling and pad maintainability. Systematic experiments analyze the influence of pad geometry, granular material, gap distance, pad height, and vacuum pressure on grasp performance. Results show that the proposed square pad achieves 280% higher grip force than a spherical pad, while providing stable jamming behavior with EPDM granules. Compared with silicone pads, the jamming pad produces 30% higher friction and 197% larger contact area under identical loading conditions. Additional experiments further demonstrate robust grasping under varying contact orientations, positional offsets, and fragile objects. These results demonstrate that modular granular-jamming pads can serve as effective distributed contact interfaces for multi-finger robotic grippers.