Nature demonstrates adaptive and extreme shape morphing via unique patterns of movement. Many of them have been explained by monolithic shape-changing mechanisms, such as chemical swelling, skin stretching, origami/kirigami morphing, or geometric eversion, that were successfully mimicked in artificial analogs. However, there still remains an unexplored regime of natural morphing that cannot be reproduced in artificial systems by a “single-mode” morphing mechanism. One example is the “dual-mode” morphing of Eurypharynx pelecanoides (commonly known as the pelican eel), which first unfolds and then inflates its mouth to maximize the probability of engulfing the prey. Here, we introduce pelican eel–inspired dual-morphing architectures that embody quasi-sequential behaviors of origami unfolding and skin stretching in response to fluid pressure. In the proposed system, fluid paths were enclosed and guided by a set of entirely stretchable origami units that imitate the morphing principle of the pelican eel’s stretchable and foldable frames. This geometric and elastomeric design of fluid networks, in which fluid pressure acts in the direction that the whole body deploys first, resulted in a quasi-sequential dual-morphing response. To verify the effectiveness of our design rule, we built an artificial creature mimicking a pelican eel and reproduced biomimetic dual-morphing behavior. By compositing the basic dual-morphing unit cells into conventional origami frames, we demonstrated architectures of soft machines that exhibit deployment-combined adaptive gripping, crawling, and large range of underwater motion. This design principle may provide guidance for designing bioinspired, adaptive, and extreme shape-morphing systems.

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Falling leaves flutter from side to side due to passive and intrinsic fluid-body coupling. Exploiting the dynamics of passive fluttering could lead to fresh perspectives for the locomotion and manipulation of thin, planar objects in fluid environments. Here, we show that the time-varying density distribution within a thin, planar body effectively elicits minimal momentum control to reorient the principal flutter axis and propel itself via directional fluttery motions. We validated the principle by developing a swimming leaf with a soft skin that can modulate local buoyancy distributions for active flutter dynamics. To show generality and field applicability, we demonstrated underwater maneuvering and manipulation of adhesive and oil-skimming sheets for environmental remediation. These findings could inspire future intelligent underwater robots and manipulation schemes.

Soft fluidic actuators produce continuous and life-like motions that are intrinsically safe, but current designs are not yet mature enough to enable large deployment with high force and low-cost fabrication methods. Herein, soft fluidic actuators with two superimposed origami architectures are reported. Driven by a fluid input, the presented dual-origami soft actuators produce quasisequential deployment and bending motion that is guided by unsymmetric unfolding of low-stretchable origami components. The dominance between the deployment and bending can be shifted by varying the unfolding behavior, enabling preprogramming of the motion. The proposed origami-inspired soft actuators are directly fabricated by low-cost fused deposition modeling 3D printing and subjected to heat treatment postprocessing to enhance the fluid sealing performance. Finally, soft gripper applications are presented and they successfully demonstrate gripping tasks where each requires strength, delicacy, precision, and dexterity. The dual-origami approach offers a design guidance for soft robots to embody grow-and-retract motion with a small initial form factor, promising for applications in next-generation soft robotic systems. An interactive preprint version of the article can be found here: https://www.authorea.com/doi/full/10. 22541/au.163698906.68661340.

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