Rigid-Soft Hybrid Suction Cups for Enhanced Anti-Torque and Energy-Efficient Attachment

In the realm of robotics, suction-based adhesion plays a pivotal role in applications ranging from object transfer to wall-climbing robots. To improve the sealing and attachment stability of suction cups, researchers have employed state-of-the-art techniques, including the use of soft materials with better conformal properties or jamming mechanisms. However, soft materials can cause undesired deformation of the suction cup under load, and the use of jamming mechanisms has limitations in terms of size and weight. This letter introduces a novel Rigid-Soft Hybrid Suction Cup (RSH-SC) designed for enhanced stability and energy-efficient attachment in nonideal conditions (i.e., suction on irregular and inclined surfaces). To emulate the octopus's dexterous suction and the limpet's robust adhesion capabilities, the RSH-SC integrates a rigid shell for better sealing and torque resistance. Notably, compared to a soft suction cup made from Ecoflex 00-50, the RSH-SC's torque deformation resistance is 550 times greater. The RSH-SC's unique structure also allows it to maintain secure attachment without continuous vacuum pressure, thus conserving energy. A crawling robot utilizing RSH-SCs showcased stable movement on ceiling, which can significantly advance the capabilities of soft robots in complex environments, paving the way for broader applications in robotics and automated systems.