Design of bionic foldable wing mimicking the hind wings of the C. buqueti bamboo weevil

The bamboo weevil, Cyrtotrachelus buqueti, has excellent flight ability and strong environmental adaptability. When it flies, its fore wings and hind wings are unfolded, whereas when it crawls, its fore wings are closed, and its flexible hind wings are regularly folded under the fore wings. In this paper, the hind wing folding/unfolding pattern of C. buqueti is analyzed and a new bionic foldable wing with rigid–flexible coupling consisting of a link mechanism and a wing membrane is constructed. The movement of the link at the wing base mimics the contraction of a muscle in the thorax that triggers scissor-like motion and the deployment of the veins. Elastic hinges are used to mimic the rotational motion of the wing base and the vein joints. The static/dynamic characteristics of bionic foldable wings are further analyzed, and the LS-DYNA software is used to investigate rigid–flexible coupling dynamics. The elastic deformation of the wing membrane, kinematic characteristics of the linkage mechanism, and modes of the whole system are calculated. Static analysis of the structure reveals that the foldable wing has excellent stiffness characteristics and load-bearing capacity. The bionic foldable wing is constructed using 3D printing technology, and its folding and unfolding performance is tested. Evaluation of its performance shows that the bionic wing has a large fold ratio and can achieve stable folding and unfolding motions. A slightly tighter assembly between the pin and the hinge hole ensures that the wing does not fold back during flapping.

Miniaturization re-establishes symmetry in the wing folding patterns of featherwing beetles

Most microinsects have feather-like bristled wings, a state known as ptiloptery, but featherwing beetles (family Ptiliidae) are unique among winged microinsects in their ability to fold such wings. An asymmetrical wing folding pattern, found also in the phylogenetically related rove beetles (Staphylinidae), was ancestral for Ptiliidae. Using scanning electron, confocal laser scanning, and optical microscopy, high-speed video recording, and 3D reconstruction, we analyze in detail the symmetrical wing folding pattern and the mechanism of the folding and unfolding of the wings in Acrotrichis sericans (Coleoptera: Ptiliidae) and show how some of the smaller featherwing beetles have reverted to strict symmetry in their wing folding. The wings are folded in three phases by bending along four lines (with the help of wing folding patches on the abdominal tergites) and locked under the closed elytra; they unfold passively in two phases, apparently with the help of the elasticity provided by resilin unevenly distributed in the wing and of convexities forming in the cross-sections of the unfolding wing, making it stiffer. The minimum duration of folding is 3.5 s; unfolding is much more rapid (minimum duration lowest recorded in beetles, 0.038 s). The folding ratio of A. sericans is 3.31 (without setae), which is greater than in any beetle in which it has been measured. The symmetrical wing folding pattern found in A. sericans and in all of the smallest ptiliids, in which ptiloptery is especially pronounced, is the only known example of symmetry re-established during miniaturization. This direction of evolution is remarkable because miniaturization is known to result in various asymmetries, while in this case miniaturization was accompanied by reversal to symmetry, probably associated with the evolution of ptiloptery. Our results on the pattern and mechanisms of wing folding and unfolding can be used in robotics for developing miniature biomimetic robots: the mechanisms of wing folding and unfolding in Ptiliidae present a challenge to engineers who currently work at designing ever smaller flying robots and may eventually produce miniature robots with foldable wings.

Earwig fan designing: Biomimetic and evolutionary biology applications

Technologies to fold structures into compact shapes are required in multiple engineering applications. Earwigs (Dermaptera) fold their fanlike hind wings in a unique, highly sophisticated manner, granting them the most compact wing storage among all insects. The structural and material composition, in-flight reinforcement mechanisms, and bistable property of earwig wings have been previously studied. However, the geometrical rules required to reproduce their complex crease patterns have remained uncertain. Here we show the method to design an earwig-inspired fan by considering the flat foldability in the origami model, as informed by X-ray microcomputed tomography imaging. As our dedicated designing software shows, the earwig fan can be customized into artificial deployable structures of different sizes and configurations for use in architecture, aerospace, mechanical engineering, and daily use items. Moreover, the proposed method is able to reconstruct the wing-folding mechanism of an ancient earwig relative, the 280-million-year-oldProtelytron permianum. This allows us to propose evolutionary patterns that explain how extant earwigs acquired their wing-folding mechanism and to project hypothetical, extinct transitional forms. Our findings can be used as the basic design guidelines in biomimetic research for harnessing the excellent engineering properties of earwig wings, and demonstrate how a geometrical designing method can reveal morphofunctional evolutionary constraints and predict plausible biological disparity in deep time.

Mini Glider Design and Implementation with Wing-Folding Mechanism

This paper describes a mini unmanned glider’s design, simulation, and manufacturing with a novel wing-folding mechanism. The mini-glider is designed for CanSat competition, which has a theme of a Mars glider concept with atmosphere data acquisition. The aim is to facilitate the transportation of the glider and to land it on the destination point by following strict rules. Having a light and compact design is important since it uses power for the transmission of sensory data only. Dimensions of the glider is produced with a wingspan that is 440 mm and a length of 304 mm. The wings can be stowed in a fixed size container that has a diameter of 125 mm and a height of 310 mm. Its weight is only 144 g and it can increase up to 500 g maximum with a payload. The mechanism, which includes springs and neodymium N48 grade magnets for a wing-folding system, is capable of being ready in 98 ms for gliding after separating from its container. The mini-glider is capable of telemetering, communicating, and conducting other sensory operations autonomously during the flight.

A STUDY OF UNMANNED GLIDER DESIGN, SIMULATION, AND MANUFACTURING

This paper describes a mini unmanned glider's design, simulation, and manufacturing with a wing-folding mechanism. The mini-glider is designed for the CANSAT 2016 competition, which has the theme of a Mars glider concept with atmosphere data acquisition. The aim is to facilitate transportation and to land it to the destination point. Having a light and compact design is important since it is a glider without an engine and it uses power only for the transmission of sensory data. The glider is produced with a wingspan which is 440 mm, and its longitudinal distance is 304 mm. The wings can be packaged in a fixed size container whose dimensions are 125 mm in diameter and 310 mm in height. The glider's weight is only 144 gr, and it can increase up to 500 gr with maximum with payload. The mechanism, which includes springs and neodymium magnets for wing-folding, is capable of being ready in 98 ms for gliding after separation from its container. The mini-glider is capable of telemetry, communications, and other sensory operations autonomously during flight.

Investigation of hindwing folding in ladybird beetles by artificial elytron transplantation and microcomputed tomography

Ladybird beetles are high-mobility insects and explore broad areas by switching between walking and flying. Their excellent wing transformation systems enabling this lifestyle are expected to provide large potential for engineering applications. However, the mechanism behind the folding of their hindwings remains unclear. The reason is that ladybird beetles close the elytra ahead of wing folding, preventing the observation of detailed processes occurring under the elytra. In the present study, artificial transparent elytra were transplanted on living ladybird beetles, thereby enabling us to observe the detailed wing-folding processes. The result revealed that in addition to the abdominal movements mentioned in previous studies, the edge and ventral surface of the elytra, as well as characteristic shaped veins, play important roles in wing folding. The structures of the wing frames enabling this folding process and detailed 3D shape of the hindwing were investigated using microcomputed tomography. The results showed that the tape spring-like elastic frame plays an important role in the wing transformation mechanism. Compared with other beetles, hindwings in ladybird beetles are characterized by two seemingly incompatible properties: (i) the wing rigidity with relatively thick veins and (ii) the compactness in stored shapes with complex crease patterns. The detailed wing-folding process revealed in this study is expected to facilitate understanding of the naturally optimized system in this excellent deployable structure.