A soft bioinspired suction cup with tunable adhesion force using shape memory alloy

Suction cups has been widely utilized to grasp objects, but they typically encounter challenges with sealing failure and non-adjustable adhesion force. In this study, a bioinspired suction cup integrated with an shape memory alloy actuated module was proposed to solve these problems. The actuating performance under different input current was firstly investigated to ensure the effectiveness of the module. Then, inspired by the surface structures of the tree frog’s toe pad, the synthetic bioinspired suction cups with hexagonal microstructures at the rims were designed. The regular cup with soft and smooth rim was also fabricated for comparison study. Furthermore, the adhesion performance and surface adaptability of different two cups were studied in both dry and water conditions on substrates with various roughness levels. The results indicated that the proposed active bioinspired suction cup exhibited higher pull-off strength and better sealing on less rough substrates. The proposed bioinspired suction cup possessed the advantages of compactness and lightweight, thus demonstrating potential for integration into arrayed suction grippers.