Development of an adaptive bionic gripping device based on coaxial shells

This study explores the development of an adaptive bionic gripping device inspired by the anatomical and functional characteristics of the marine polychaete worm Glycera Phyllodocida.This organism's unique ability to evert its jaw structure for prey capture has served as a biological model for designing a novel robotic gripper.The proposed design is based on a series of coaxial elastomeric shells capable of inverting and returning to their original form through pneumatic actuation.The gripper incorporates a guiding cylinder to control the inversion direction, concentric reinforcement ribs to regulate membrane deformation, and a variable wall thickness for enhanced adaptability.The device demonstrates a high level of conformity to objects with diverse geometries and materials.The gripping process is divided into three stages: initial contact, membrane wrapping, and retention, ensuring secure holding with minimal deformation of the target object.Experimental validation has confirmed the effectiveness of the device in handling cylindrical, conical, and spherical samples with diameters ranging from 92% to 116% of the guiding cylinder's diameter.Furthermore, mathematical modeling has been employed to predict gripping forces, membrane behavior under varying internal pressures, and the effect of membrane stiffness and geometry on operational efficiency.Integration of vacuum assistance enhances retention strength, especially for heavier objects, and improves membrane retraction speed.The findings highlight the potential of this bioinspired gripper for use in food processing and packaging industries, where objects of varying sizes and delicate surfaces must be handled with precision and adaptability.Compared to traditional rigid or pneumatic soft grippers, the developed prototype provides a balanced combination of flexibility, structural stability, and control.This research contributes a promising advancement in the field of soft robotics and biomimetic engineering, paving the way for the design of next-generation adaptive manipulators suitable for realworld applications.