Inverse design of flat-foldable thick origami with smooth curved surface

TL;DR

This paper introduces an inverse design method for thick origami that can fold flat while forming smooth curved surfaces, expanding origami's application scope in aerospace and communication systems.

Contribution

It develops a novel inverse design approach that enables flat-foldable thick origami with smooth curved surfaces, including a graph-based configuration enumeration and increased packaging ratio control.

Findings

Successfully designed and fabricated a deployable origami wing

Demonstrated the wing's functionality through flight testing under aerodynamic loads

Showed increased packaging ratio with more cells in the layout

Abstract

Origami as a deployable structure offers the unique advantage of achieving compact stowage via flat-folding while forming a well-defined surface composed of rigid panels upon deployment. However, since origami consists of flat facets, it is inherently limited in forming smooth curved surfaces upon deployment. This limitation restricts its applicability in systems where smooth curved geometries are essential for performance, such as aerospace systems and electromagnetic communication devices. Herein, we propose an inverse design methodology for thick origami that is capable of flat-folding while forming a smooth curved outer surface upon deployment. By establishing flat-foldable constraints that specify the positions of the creases, our method constructs thick origami capable of flat-folding even with panels that include a curved facet. Furthermore, by representing the origami layout as a graph, we enumerate all possible origami configurations and enable flexible design of the internal structure. Analytical results show that the optimized packaging ratio increases as the number of cells in a layout increases, indicating that the proposed design methodology provides controllability over the packaging ratio through the number of cells. Using our proposed design methodology, we fabricated a deployable origami wing and demonstrated its functionality through successful flight testing, in which the wing was subjected to aerodynamic loads. Our work proposes a new strategy for packaging smooth curved surfaces, addressing the packaging challenges encountered in aerospace and electromagnetic communications and thereby providing greater design freedom.