Octopus‐Inspired Adaptable Soft Grippers Based on 4D Printing: Numerical Modeling, Inverse Design, and Experimental Validation

Abstract

Soft grippers based on stimuli‐responsive materials show great promise to perform safe interaction and adaptive functions in unstructured environments. Hence, improving flexibility and designability of the stimuli‐responsive soft grippers for better grasping ability are highly desired. Inspired by the biological structure of octopuses, a class of temperature‐driven polylactic acid grippers is fabricated by 4D printing in this work, which consists of two types of bilayer structures, separately imitating the web and tentacles of an octopus. Compared with the traditional pure‐bending soft grippers, the integrated structure results in a 1.5 times wider reachable area and enhanced flexibility. The complex grasping behaviors are predicted with the 4D printing parameters (i.e., printing paths and printing speeds) using the reduced bilayer plate theory. Moreover, a method for determining the printing parameters of the gripper is provided to realize the desired grasping behavior depending on different objects. The feasibility of the design method is experimentally verified by gasping three distinctive objects, including an egg, a weight, and a Metatron's cube, which is in good agreement with the simulation results. Herein, a promising strategy is provided to achieve the easy‐fabricated, low‐cost, and versatile soft graspers using smart materials.

Soft octopus-inspired suction cups using dielectric elastomer actuators with sensing capabilities

“…Researchers are studying how various mechanisms have evolved in nature, aiming to mimic the adaptability and versatility of biological systems without necessarily replicating their exact structure [1][2][3][4]. Such robots aim to impersonate a variety of functions from the animal and plant kingdom, including the suction capabilities of octopus suction cups [5][6][7], the adhesive properties of gecko feet [8], the movement of octopus tentacles [9][10][11], the grasping mechanism found in bird claws [12], the walking gait of insects [13], or the snapping mechanism of the Venus flytrap [14,15].…”

Variable stiffness soft robotic gripper: design, development, and prospects

“…By controlling the bending motion of the fingers, a line-shaped contact surface is formed with the object, facilitating grasping or manipulation. Unlike the LC mode, the third mode is SC [10,[34][35][36][37][38][39], often employing a large contact surface for enveloping or grasping. In this mode, the contact surface adapts to the object's shape variations in different dimensions, providing extensive coverage.…”