Abstract

In underwater salvage operations, robotic grippers with high sensitivity and stable clamping performance significantly enhance retrieval efficiency while ensuring the integrity of target objects. Octopuses can accurately perceive information of grasped objects through their arms and dorsal membranes, utilizing suction cups for precise object capture. Inspired by these sensing and grasping mechanisms, this paper proposes a bionic underwater octopus tactile gripper (UOTG) based on the triboelectric nanogenerator. The UOTG mainly features a network of suction cup-like structures and embedded triboelectric sensors, which enable it to sense external stimuli in underwater low-visibility and noisy environments. Its fully soft structure facilitates adaptation to varying object shapes and sizes. The triboelectric sensor array generates electrical signals through contact-separation effects, providing tactile information regarding the pressure and deformation of objects being grasped. Notably, the incorporation of MXene, a novel functional material, into the sensing unit of UOTG significantly enhances charge transfer efficiency and sensor sensitivity while ensuring stable tactile perception performance in complex underwater environments. The UOTG demonstrates a linear sensitivity to grasping force and is capable of detecting object detachment, estimating object volume, and identifying object shape and hardness. Experimental results reveal recognition accuracies of 98.3 % and 98.0 % for object shape and hardness, respectively. These findings demonstrate that the UOTG enhances underwater sensing capabilities and holds great potential for applications in underwater grasping and salvage operations.