Origami Pattern Research Articles

Enhancing Strategy of Triboelectric Nanogenerator via Origami Pattern by Harvesting Mechanical Motion and Wind Flow

Triboelectric nanogenerators (TENGs) are promising energy-harvesting devices that generate electricity from mechanical energy. However, the electrical outputs of typical TENGs are limited because of the fundamental mechanism by which TENGs require a certain amount of space for contact-separation motion. Therefore, we developed an origami-based vertical/fluttering hybrid TENG (OVFH-TENG), which is the innovative structure that can generate electricity from both vertical movement and wind flow which is generated by vertical movement. It consists of a vertical TENG and a fluttering TENG where vertical TENGs can generate electricity and wind flow from mechanical input and the fluttering TENGs can generate electricity from the wind flow which is generated by its own operation process. Thus, OVFH-TENG can effectively harvest energy from vertical contact and fluttering motions with a single input. The optimized OVFH-TENG generated a 34.7% higher output than the general contact-separation TENG. Finally, the OVFH-TENG was able to light 180 LEDs, which was not possible with a general contact-separation TENG.

Design Methodology for a 3D Printable Multi‐Degree of Freedom Soft Actuator Using Geometric Origami Patterns

Soft pneumatic actuators (SPAs) have applications in various domains due to their compliance, low cost, and lightweight characteristics. Herein, a geometric origami design for 3‐degree of freedom (DoF) SPAs is presented, which enables manufacturing using 3D printing at one go without any support structure. The proposed method uses a general design parameterization that works for multiple types of cylindrical origami patterns (Kresling, cylindrical Miura, Yoshimura, and Accordion). It is shown that a 3‐DoF pneumatic actuator capable of bending and extension can be constructed by superimposing two cylindrical origami patterns to create a separation of chambers inside of the module. In addition, the design parameters are chosen to reduce the strain during deformation and maximize the output forces of the origami actuator. The actuator is manufactured, and its motion and force profiles are experimentally characterized. The designed origami actuator can bend from to and the length during operation can vary between and of the initial length.

Folding Miura-Ori of Uniform Thickness With One Degree-of-Freedom

Abstract The Miura-ori is an origami pattern with bi-directional folding capable of transforming a large thin sheet into a compact volume with a single degree-of-freedom (DoF). A common Miura-ori pattern consists of identical rigid parallelogram facets that can rotate about the creases without twisting or stretching. However, large gaps along the hinges or uneven surfaces in deployed states are inevitable when thick panels are used. In this paper, the authors add uniform thickness to a Miura-ori tessellation and connect the thick panels by revolute joints on either the top or the bottom facets of the panels for valley creases or mountain creases, respectively. To enable its folding, regular slits are made on some facets not only to remove the excess kinematic constraints but also to accommodate the panel thickness during the folding process. Having made the cuts, we demonstrate that the resultant assembly can fold into a compact package with one DoF. We further notice that although the slits open up during the folding process, they close in the deployed state of the assembly, giving flat and continuous surfaces on both the top and bottom sides. The same method can also be applied to fold the derivatives of the Miura-ori, such as double-corrugated patterns.

Shear and shear-induced normal responses of origami cylinders relate to their structural asymmetries

Origami cylinders have been studied extensively under compression, however, their normal force response under shear deformation is still ill-understood. We experimentally studied the shear-induced normal force of these systems and provided a simple model to predict this response in Yoshimura and Kresling origami cylinders in the range of small deformations. Besides that, the effect of disorder is little understood in those origami patterns. Therefore, we investigate the disorder effect and show it can lead to diverse normal responses perpendicular to shear deformation in crumpled Yoshimura, with slopes of the force perpendicular to torsion that can be positive, zero, or negative depending on the disordered pattern of folds. The disorder leads to an asymmetry concerning the shearing direction, which we quantified via an asymmetry index from the 2D Fast Fourier transform spectrum of the crease pattern images. This asymmetry index is found to be linearly related to the slope of the normal force-torsion relationship.

An origami-inspired energy absorber

The design of effective and compact energy absorption systems is key to the survivability and durability of many man-made structures and machines. To this end, this work presents the design, assessment, and implementation of a novel origami-inspired energy absorber that is based on the Kresling origami pattern. The absorber consists of a Kresling origami column positioned between the loading point and an energy dissipation module. By exploiting its unique inherent translation-to-rotation coupling feature, the primary function of the Kresling column is to transmit uniaxial incident loads (shock or impact) into localized rotational energy that can then be dissipated in a viscous fluid chamber. The proposed system has several unique advantages over traditional designs including the ability to (i) dissipate energy associated with both torsional and uniaxial loads, (ii) control the rotational velocity profile to maximize energy dissipation, and (iii) customize the restoring-force behavior of the Kresling column to different applications. Furthermore, the proposed design is more compact since it can realize the same stroke distance of the traditional translational design while being considerably shorter. Through extensive computational modeling, parametric studies, and experimental testing, it is demonstrated that the proposed design can be optimized to absorb all the imparted energy; and out of the absorbed energy, around 40% can be dissipated in the viscous fluid, while the rest is either dissipated by the viscoelasticity of the origami column or stored in it as potential energy.

The Kresling origami spring: a review and assessment

Abstract Structures inspired by the Kresling origami pattern have recently emerged as a foundation for building functional engineering systems with versatile characteristics that target niche applications spanning different technological fields. Their light weight, deployability, modularity, and customizability are a few of the key characteristics that continue to drive their implementation in robotics, aerospace structures, metamaterial and sensor design, switching, actuation, energy harvesting and absorption, and wireless communications, among many other examples. This work aims to perform a systematic review of the literature to assess the potential of the Kresling origami springs as a structural component for engineering design keeping three objectives in mind: (i) facilitating future research by summarizing and categorizing the current literature, (ii) identifying the current shortcomings and voids, and (iii) proposing directions for future research to fill those voids.

Origami‐Patterned Rigidification for Soft Robotic Bifurcation

The fluid‐transportation functions based on the volume‐regulating behavior of the chamber‐like organs inspire the development of artificial organs. Due to the intrinsic compliance of soft robotics for biomimicking purposes and the volume‐regulation capability of the 3D origami patterns, the soft robots with origami patterns show promising potential in such research. However, the folding deformation of the origami facets cannot be straightforwardly implemented as the actuation or the body movement, and the predetermined movements of the pattern limit the appropriate functions for specific applications. In this work, an origami‐patterned rigidification (OPR) method is proposed for applying rigid origami mechanisms (herein, the cuboctahedron origami ball) to the chamber‐like structure of soft robots. The motion of the soft robot is programmed by purposefully rigidified the soft chamber following the pattern. The resultant OPR structures are granted with functions corresponding to the predetermined motion of the pattern, and the expanded movements through the bifurcation brought by the soft–rigid characteristics. The concept, design, and fabrication of the OPR robot are presented. By analyzing the deformation of the soft creases, the kinematic models of the predetermined and expanded degrees of freedom are presented and verified by experiments. The extended functions of two OPR robots are demonstrated.

Packing optimization and design of the deployable parabolic rigid antenna based on origami

This paper introduces a novel approach for optimizing the packing and design of deployable parabolic rigid antenna structures based on origami, tailored to meet specific requirements related to the number of solid-surface blocks and the size of the folded antenna. The study begins by selecting a single-vertex four-crease configuration with one degree of freedom from the origami pattern, guided by mobility analysis, to optimize block arrangement. Subsequently, a planar model is employed to qualitatively examine the impact of geometric parameters on the stowage efficiency of the antenna. Building upon the insights gained from the planar model, an optimization framework for the parabolic rigid deployable antenna structure is established. The objective function of the optimization is the stowage volume, while simultaneously adhering to stiffness, collision, and mobility constraints. The design parameters of the antenna structure are thoroughly analyzed. To mitigate collision risks during folding, design considerations are applied to placement of support nodes, location of rotating axes, and block division, leveraging the optimized parameters. The practicality of the proposed method is successfully demonstrated through the folding of a simulated 3D model and of a physical 3D printed model. These tangible representations show the feasibility of the presented approach, affirming its potential applicability in the optimization and design of deployable parabolic rigid antenna structures.

Design and mechanical properties analysis of a cellular Waterbomb origami structure

Cellular structures are commonly used to design energy-absorbing structures, and origami structures are becoming a prevalent method of cellular structure design. This paper proposes a foldable cellular structure based on the Waterbomb origami pattern. The geometrical configuration of this structure is described. Quasi-static compression tests of the origami tube cell of this cellular structure are conducted, and load-displacement relationship curves are obtained. Numerical simulations are carried out to analyze the effects of aspect ratio, folding angle, thickness and number of layers of origami tubes on initial peak force and specific energy absorption (SEA). Calculation formulas for initial peak force and SEA are obtained by the multiple linear regression method. The degree of influence of each parameter on the mechanical properties of the single-layer tube cell is compared. The results show that the cellular structure exhibits negative stiffness and periodic load-bearing capacity, as well as folding angle has the most significant effect on the load-bearing and energy-absorbing capacity. By adjusting the design parameters, the stiffness, load-bearing capacity and energy absorption capacity of this cellular structure can be adjusted, which shows the programmable mechanical properties of this cellular structure. The foldability and the smooth periodic load-bearing capacity give the structure potential for application as an energy-absorbing structure.

Rigid-flexible coupled origami robots via multimaterial 3D printing

Soft robots have significant advantages in flexibility and adaptability and have potential applications in the field of engineering. Unlike traditional manufacturing methods, three-dimensional (3D) printing provides a fast way to fabricate customized and multi-functional robots. However, the fabrication of soft robots requires multimaterial printers and the high-accuracy multi-step assembly process. Among them, fused deposition modeling (FDM) technology has taken the lead compared to other 3D printing methods due to its ease of use, accuracy, and repeatability. However, the FDM multimaterial printing has not been thoroughly explored. Here, we proposed a rigid and flexible material integrated printing approach based on FDM 3D printing technology and reported a cable-driven flexible pipe robot based on Yoshimura origami crease patterns. The implementations show that the robot can realize four-direction bending effectively by the corresponding drive control, which indicates the feasibility of our design and manufacturing method. The proposed approach paves an effective way to design and fabricate the rigid-flexible robot and other devices in the future.

Origami-Wrapped Structures with Corrugated Unfolded Forms

Stowage schemes based on origami wrapping patterns are useful for the design of various deployable spacecraft structures. These origami patterns allow for the compact stowage of flat sheets of small thickness. Typically, some other structure is needed to stiffen this thin sheet when it is fully deployed and flat. This paper describes a class of thin-shell structures that can be compactly stowed using origami wrapping methods but have a corrugated form when deployed. These structures cannot reach a flat state by design. The persistent corrugations provide stiffness without the need for an external structure, thus leading to overall savings in mass and complexity. The geometrical design of the corrugations is highly tunable. This paper describes a method for generating the form of these folding structures; the method guarantees that the structure can be unstrained both when compactly wrapped and when fully deployed. Test articles are fabricated to demonstrate the concept, and stowage experiments and stiffness experiments are conducted. A structural finite element modeling procedure is described to predict the deployed stiffness of these structures, and the stiffness predictions match the experimental results.

Configuration design and crease topology of origami-inspired spinning space deployable structures

Origami-inspired space deployable structures can be transformed from the folded states into the deployed states in orbit, which satisfied the demands of complex space missions and had been widely used in the space field. It remains to be investigated how the space deployable structures realized a large deployable ratio in the crease design process of origami patterns for the storage space limitation of spacecraft structures. Origami-inspired Regular Polygons Deployable Structures (RPDS) were proposed by designing the origami configurations and analyzing the deployable mechanism from existing space deployable structures, and a novel crease topology with three different approaches was presented in repeating origami modules to enhance the deployable ratio. The topology results indicated that the deployable ratio of RPDS can be increased effectively by shortening the storage height or performing multi-stage deployment, and the flexibility of RPDS can be verified by changing the shape of the central body. The configuration rationality and deployable reliability of RPDS are confirmed by kinematic modeling and numerical simulation. This study provides new insights into extraordinary geometrical and folding properties of origami-inspired deployable structures via configuration design and crease topology, which can be extended to other origami patterns in various origami-inspired applications.

Geometric mechanics of hybrid origami assemblies combining developable and non-developable patterns

Origami provides a method to transform a flat surface into complex three-dimensional geometries, which has applications in deployable structures, meta-materials, robotics and beyond. The Miura-ori and the eggbox are two fundamental planar origami patterns. Both patterns have been studied closely, and have become the basis for many engineering applications and derivative origami patterns. Here, we study the hybrid structure formed by combining unit cells of the Miura-ori and eggbox patterns. We find the compatibility constraints required to form the hybrid structure and derive properties of its kinematics such as self-locking and Poisson’s ratio. We then compare the aforementioned properties of the Miura-eggbox hybrid with those of the morph pattern, another generalization of the Miura-ori and eggbox patterns. In addition, we study the structure formed by combining all three unit cells of the Miura-ori, eggbox and morph. Our results show that such patterns have tunable self-locking states and Poisson’s ratio beyond their constituent components. Hybrid patterns formed by combining different origami patterns are an avenue to derive more functionality from simple constituents for engineering applications.

Origami-Based Haptic Syringe for Local Anesthesia Simulator.

Although medical simulators have benefited from the use of haptics and virtual reality (VR) for decades, the former has become the bottleneck in producing a low-cost, compact, and accurate training experience. This is particularly the case for the inferior alveolar nerve block (IANB) procedure in dentistry, which is one of the most difficult motor skills to acquire. As existing works are still oversimplified or overcomplicated for practical deployment, we introduce an origami-based haptic syringe interface for IANB local anesthesia training. By harnessing the versatile mechanical tunability of the Kresling origami pattern, our interface simulated the tactile experience of the plunger while injecting the anesthetic solution. We present the design, development, and characterization process, as well as a preliminary usability study. The force profile generated by the syringe interface is perceptually similar with that of the Carpule syringe. The usability study suggests that the haptic syringe significantly improves the IANB training simulation and its potential to be utilized in several other medical training/simulation applications.

Variable Stiffness Fibers Enabled Universal and Programmable Re-Foldability Strategy for Modular Soft Robotics.

Origami is a rich source of inspiration for creating soft actuators with complex deformations. However, implementing the re-foldability of origami on soft actuators remains a significant challenge. Herein, a universal and programmable re-foldability strategy is reported to integrate multiple origami patterns into a single soft origami actuator, thereby enabling multimode morphing capability. This strategy can selectively activate and deactivate origami creases through variable stiffness fibers. The utilization of these fibers enables the programmability of crease pattern quantity and types within a single actuator, which expands the morphing modes and deformation ranges without increasing their physical size and chamber number. The universality of this approach is demonstrated by developing a series of re-foldable soft origami actuators. Moreover, these soft origami actuators are utilized to construct a bidirectional crawling robot and a multimode soft gripper capable of adapting to object size, grasping orientation, and placing orientation. This work represents a significant step forward in the design of multifunctional soft actuators and holds great potential for the advancement of agile and versatile soft robots.

Kinematic Solutions and Bifurcation Analysis of Single Vertex Origami Pattern

The bifurcation behavior of deployable structures has received significant attention from different fields. Apart from pin-jointed structures, origami, as a thriving inspiration for valuable and practical deployable structures, develops singular configurations along its kinematic paths. The kinematic behaviors of single vertex origami patterns are studied in this work. General four-crease patterns and symmetric six-crease patterns are thoroughly investigated based on the analytical solutions obtained by constraint equations. Moreover, the corresponding motion paths are described to discuss the bifurcation behavior. A comparative analysis of kinematic behaviors with the different actuating coordinates is performed. Three types of bifurcation are analyzed, concluding that three different motion paths cannot occur at the same time. The research findings of the present work can contribute to the development of novel deployable structures and mechanical systems.

Approximating complex 3D curves using origami spring structures

Origami provides a versatile platform for creating intricate three-dimensional (3D) reconfigurable structures through folding techniques. However, the applications of origami patterns are restricted due to limited deformation modes and complex actuation. Here we explore origami spring structures as a solution to address these limitations by approximating complex 3D curves with an underactuated scheme. By doing so, we showcase the reconfigurability and versatility of origami springs while tackling control complexity. Through the introduction of virtual creases, we simplify non-rigid deformations and enable accurate descriptions of their 3D configurations. Furthermore, we develop inverse kinematics optimization algorithms to determine optimal configurations closely approximating given 3D curves with full actuation and underactuated situations. Experimental realization of various 3D curves demonstrates the feasibility and effectiveness of our proposed approach. This research could find practical utility in soft robotics, flexible mechanisms, and deployable structures.

Optimization of the octagonal origami tube energy absorption using the artificial neural network and heuristic method

This article presents a hybrid optimization approach for improving the crashworthiness characteristics of thin-walled metallic tubes using a unique multilayered origami pattern. In the quasi-static axial loading condition, a total of 120 thin-walled tube samples were simulated using the full factorial design method to assess the impact of geometric parameters on their crashworthiness behavior, including the dihedral angle, module number, and outer layer height. Additionally, based on the input parameters, an artificial neural network was implemented to estimate the mechanical response of the tubes. Then, to determine the ideal design parameters, a hybrid multi-objective optimization approach was used. The Technique for Order of Preference by Similarity to Ideal Solution technique was utilized to extract the optimal design to balance the objectives of energy absorption and initial peak force. The specific energy absorption of the optimal tube was discovered to be 68% higher than that of the base tube. The simulation results demonstrate that the proposed multilayered origami pattern provides a unique structure that improves the crashworthiness properties of the thin-walled metallic tubes.

Modular self-lock origami: Design, modeling, and simulation to improve the performance of a rotational joint

Origami structures have been widely explored in robotics due to their many potential advantages. Origami robots can be very compact, as well as cheap and efficient to produce. In particular, they can be constructed in a flat format using modern manufacturing techniques. Rotational motion is essential for robotics, and a variety of origami rotational joints have been proposed in the literature. However, few of these are even approximately flat-foldable. One potential enabler of flat origami rotational joints is the inclusion of lightweight pneumatic pouches which actuate the origami’s folds; however, pouch actuators only enable a relatively small amount of rotational displacement. The previously proposed four-vertex origami is a flat-foldable structure that provides an angular multiplier for a pouch actuator, but suffers from a degenerate state. This paper presents a novel rigid origami, the self-lock origami, which eliminates this degeneracy by slightly relaxing the assumption of flat-foldability. It includes the earwig wing-inspired origami pattern with inextensible and flexible components. This joint is analyzed in terms of a trade-off between the angular multiplier and the mechanical advantage. Furthermore, the self-lock origami is a modular joint that can be connected to similar or different joints to produce complex movements for various applications; three different manipulator designs are introduced as a proof of concept.

Fabrication of Origami Soft Gripper Using On-Fabric 3D Printing

In this work, we have presented a soft encapsulating gripper for gentle grasps. This was enabled by a series of soft origami patterns, such as the Yoshimura pattern, which was directly printed on fabric. The proposed gripper features a deformable body that enables safe interaction with its surroundings, gentle grasps of delicate and fragile objects, and encapsulated structures allowing for noninvasive enclosing. The gripper was fabricated by a direct 3D printing of soft materials on fabric. This allowed for the stiffness adjustment of gripper components and a simple fabrication process. We evaluated the grasping performance of the proposed gripper with several delicate and ultra-gentle objects. It was concluded that the proposed gripper could manipulate delicate objects from fruits to silicone jellyfishes and, therefore, have considerable potential for use as improved soft encapsulating grippers in agriculture and engineering fields.