Adaptive Hierarchical Origami Metastructures (2311.18055v1)

Abstract: Shape-morphing capabilities are crucial for enabling multifunctionality in both biological and artificial systems. Various strategies for shape morphing have been proposed for applications in metamaterials and robotics. However, few of these approaches have achieved the ability to seamlessly transform into a multitude of volumetric shapes post-fabrication using a relatively simple actuation and control mechanism. Taking inspiration from thick origami and hierarchies in nature, we present a new hierarchical construction method based on polyhedrons to create an extensive library of compact origami metastructures. We show that a single hierarchical origami structure can autonomously adapt to over 103 versatile architectural configurations, achieved with the utilization of fewer than 3 actuation degrees of freedom and employing simple transition kinematics. We uncover the fundamental principles governing theses shape transformation through theoretical models. Furthermore, we also demonstrate the wide-ranging potential applications of these transformable hierarchical structures. These include their uses as untethered and autonomous robotic transformers capable of various gait-shifting and multidirectional locomotion, as well as rapidly self-deployable and self-reconfigurable architecture, exemplifying its scalability up to the meter scale. Lastly, we introduce the concept of multitask reconfigurable and deployable space robots and habitats, showcasing the adaptability and versatility of these metastructures.

• The paper introduces a hierarchical design that enables more than ten distinct configurations using just three active degrees of freedom.
• A customized simulation environment validated the simple, stepwise kinematics of local shape transitions.
• The design offers practical applications in robotics, scalable architecture, and space exploration through its modular reconfigurability.

Introduction

The advent of shape-morphing structures has opened up a new dimension of possibilities for multifunctional systems in diverse fields such as architecture, robotics, and aerospace. Biological systems, like the mimic octopus, offer examples of versatile shape adaptation, transforming into multiple shapes for survival. Meanwhile, the field of artificial systems has seen several strategies for shape morphing emerge. Despite progress, a key challenge remains in finding the balance between the versatility of shape morphing and the simplicity of actuation and control, particularly in systems with a high number of degrees of freedom (DOFs).

Hierarchical Shape-Morphing Structures

To address this challenge, a novel approach is presented that draws inspiration from the principles of thick origami and hierarchic designs observed in nature. Researchers have developed a construction method based on hierarchical architecture and polyhedron-based structures. The resulting origami metastructures feature compact closed-loop linkages at varying hierarchical levels, which, although complex, require as few as three active DOFs to transition through over ten distinct configurations. This efficiency is achieved through the introduction of geometric constraints intrinsic to the hierarchical design, which reduce the number of active reconfiguration DOFs. The versatility of these metastructures is enhanced by a vast library of potential shapes and configurations, enabling multifunctional capabilities with simple operational control.

Simple Transition Kinematics and Applications

The reconfiguration paths of these structures can be characterized by simple kinematics, defined by local and stepwise transitions between different shapes. This simplicity in actuation is evidenced by the structure's ability to morph into a variety of intricate architectural forms with minimal active DOFs. The structural configurations were examined through a customized software simulation environment, validating the theoretical model and enabling systematic studies of the reconfiguration process. The researchers envision a wide array of promising applications, from untethered and autonomously adaptable robotics that can exhibit various gaits and directional changes to scalable architectural designs suited for emergency shelters.

Future Potential and Space Applications

Looking forward, the proposed design strategy unveils exciting opportunities in the domain of space exploration. The hierarchical metastructures' adaptability, modularity, scalability, and ease of deployment make them suitable candidates for reconfigurable space robots and habitats. Such applications would benefit from the absence of gravity-related constraints, potentially simplifying the actuation mechanisms even further. These robotically assembled and disassembled structures could perform multiple tasks, from collision avoidance to architectural construction and energy harvesting, potentially leading to novel implementations within the space environment.