Wing Folding Mechanism Research Articles

Multi-Level Switching Control Scheme for Folding Wing VTOL UAV Based on Dynamic Allocation

A folding wing vertical take-off and landing (VTOL) UAV is capable of transitioning between quadrotor and fixed-wing modes, but significant alterations occur in its dynamics model and maneuvering mode during the transformation process, thereby imposing greater demands on the adaptability of its control system. In this paper, a multi-level switching control scheme based on dynamic allocation is proposed for the deformation stage. Firstly, according to the physical characteristics of the wing folding mechanism, a dynamic model is established. The influence of the incoming flow on the rotors is considered, and the dynamic coupling characteristics in its transition process are analyzed. Secondly, by inverting the changes in rotor position and axial direction, a dynamic allocation algorithm for the rotors is designed. Then, the quadrotor controller and the fixed-wing controller are switched and mixed in multiple loops to form a multi-level switching control scheme. Finally, the simulation results show that the designed multi-level switching control scheme is effective and robust in forward and backward deformation processes, and its anti-interference ability is stronger compared with that of the control scheme without dynamic allocation.

Design and Flight Test of a Tube-Launched Unmanned Aerial Vehicle

Unmanned aerial vehicles (UAVs) have already proven valuable for intelligence, search, and reconnaissance missions; however, their integration into manned aircraft to augment existing capabilities is still an emerging field. This paper describes the design of an aircraft that fits inside a G-sized sonobuoy canister, deploys from a manned aircraft in-flight, and flies for up to 111 km and 83 min while providing telemetry to a remote operator. While UAVs with similar performance requirements exist, most were designed to fit in larger canisters. Multiple UAVs can be deployed in the air to expand the search capabilities of manned aircraft, ultimately allowing a larger search area per cost compared to manned aircraft alone. Individual performance characteristics of the aircraft such as aerodynamics, weight, propulsion, and stability were developed in the preliminary design phase based on given performance requirements. The performance of the aircraft was assessed using analytical and empirical methods. Wing folding mechanisms were prototyped for use on the production aircraft for flight testing. Propulsion, aerodynamic, and structural capabilities were validated separately using experimental methods. The folding mechanisms used in this UAV allow it to achieve the benefits of a longer wingspan while remaining compact and easy to deploy.

Origin of the propatagium in non-avian dinosaurs

Avian wings as organs for aerial locomotion are furnished with a highly specialized musculoskeletal system compared with the forelimbs of other tetrapod vertebrates. Among the specializations, the propatagium, which accompanies a skeletal muscle spanning between the shoulder and wrist on the leading edge of the wing, represents an evolutionary novelty established at a certain point in the lineage toward crown birds. However, because of the rarity of soft-tissue preservation in the fossil record, the evolutionary origin of the avian propatagium has remained elusive. Here we focus on articulated skeletons in the fossil record to show that angles of elbow joints in fossils are indicators of the propatagium in extant lineages of diapsids (crown birds and non-dinosaurian diapsids), and then use this relationship to narrow down the phylogenetic position acquiring the propatagium to the common ancestor of maniraptorans. Our analyses support the hypothesis that the preserved propatagium-like soft tissues in non-avian theropod dinosaurs (oviraptorosaurian Caudipteryx and dromaeosaurian Microraptor) are homologous with the avian propatagium, and indicate that all maniraptoran dinosaurs likely possessed the propatagium even before the origin of flight. On the other hand, the preserved angles of wrist joints in non-avian theropods are significantly greater than those in birds, suggesting that the avian interlocking wing-folding mechanism involving the ulna and radius had not fully evolved in non-avian theropods. Our study underscores that the avian wing was acquired through modifications of preexisting structures including the feather and propatagium.

Modeling and Design Optimization of a New Piezoelectric Inchworm Actuator with Screw Clamping Mechanisms.

A new piezoelectric inchworm actuator with screw clamping mechanisms has been developed recently for the wing folding mechanism of a small unmanned aircraft where the actuator power density is a great concern. Considering that the prototype actuator was designed just with engineering intuition and the performance optimization through experimental developments would take a vast amount of cost and time, a mathematical model was developed to investigate the actuator's critical design parameters and optimize its presently undesirable performance. Based on the lumped parameter method reported previously, and taking full account of the detailed modeling of the complex actuator housing and the actual nonlinear behaviors from the high-force contact and friction occurring at the screw-nut interface, as well as the output performance of the main drive elements including the piezoelectric stack and hollow ultrasonic motors (HUSMs), this model was built and then was experimentally verified for its accuracy and availability. Finally, nine design parameters were studied for their individual effect on the actuator's output using the proposed model. The simulation results indicate that the performance can be considerably improved by performing a slight modification to the prototype, and the dynamic modeling and parameter optimization methods used in this study can also serve as a useful reference for the design of similar piezoelectric inchworm actuators with intermittent clamping behaviors.

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-old Protelytron 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.

Bio-inspired wing-folding mechanism of micro air vehicle (MAV)

Over the past few years, many researchers have shown an interest in micro air vehicle (MAV), since it can be used for rescue mission and investigation of danger zone which is difficult for human being to enter. In recent years, many researchers try to develop high-performance MAVs, but a little attention has been given to the wing-folding mechanism of wings. When the bird and the flying insects land, they usually fold their wings. If they do not fold their wings, their movement area is limited. In this paper, we focused on the artificial wing-folding mechanism. We designed a new artificial wing that has link mechanism. With the wing-folding mechanism, the wing span was reduced to 15%. In addition, we set feathers separately on the end of wings like those of real birds. The wings make thrust force by the change of the shape of the feathers. However, the wings could not produce enough lift force to lift it. Therefore, we have come to the conclusion that it is necessary to optimize the wings design to get stronger lift force by flapping.

Reinvestigation of <i>Protelytron permianum</i> (Insecta; Early Permian; USA) as an example for applying reflectance transformation imaging to insect imprint fossils

Abstract. We reinvestigated the holotype of Protelytron permianum, one of the earliest putative stem-dermapteran (i.e. stem-earwig). We recurred to reflectance transformation imaging (RTI) to deliver exhaustive and interactive photographic data. We were able to ascertain the occurrence of broadenings located along veins of the hind wing vannus and forming an arc, as well as a series of radiating folds, alternatively concave and convex. Such an organization is diagnostic of Dermaptera, in which it is indicative of hind wing folding mechanisms, particularly elaborated in these insects. We provide a foldable, paper model of the hind wing. Based on the case presented herein we anticipate that RTI process will be a major upheaval in the documentation of fossil insects preserved as imprints.

Analysis of the Wing Mechanism Movement Parameters of Selected Beetle Species (Coleoptera)

This study presents a structural and functional analysis of the wing bending and folding mechanism of a selected beetle species. Insect motility studies, with regard to the anatomical structure, were performed. The main inner wing structures were highlighted and their mechanical properties and functions were determined. The structure parameters as mechanisms bodies that allow wings of various beetle species to bend and fold were defined.

J1910104 甲虫の翅に見られる弾性展開とその折り畳みメカニズム

This study focuses on a group of beetles that have unfolding-stable-type wings and aims to reveal their wing-folding/unfolding mechanisms. These beetle use their wing elasticity for deployment and can therefore quickly take off. First, on the basis of the reports of entomologists, the authors desrcibe the factors related to the actuation of insect wing folding and unfolding. Then, the detailed motions involved in take-off and wing storing in ladybird beetles and rove beetles are observed by a high-speed camera. The analysis of these movies reveals the detailed processes of wing-unfolding and folding in these two species. Intrinsic elasticity plays a major role in wing development in both species. In the case of wing storing, a ladybird beetle folds its hindwings into a symmetric pattern using a simple up-down movement of the abdomen, whereas rove beetles also use their abdomens for wing-folding, but their movements are more complex, and the crease patterns are asymmetric. Finally, the characteristics of each wing-folding mechanism are summarized and the potential for engineering applications are discussed. Wing-folding/unfolding mechanisms in these insects have various unique capabilities which will provide new possibilities for designing deployable structures.

Functional and Structural Analysis of Wing Folding Mechanism Based on Cockchafer (Melolontha Melolontha)

Abstract Insects are among nature’s most nimble flyers. In this paper we present the functional and structural analysis of wing joint mechanism. Detailed action of the axillary plates and their mutual interaction was also described. Because of the small dimensions of the wing joint elements and the limited resolution of the light microscope, the authors used a scanning electron microscope. Based upon the knowledge of working principles of beetle flight apparatus a wing joint mechanism kinematics model has been developed.

Folding wings like a cockroach: a review of transverse wing folding ensign wasps (Hymenoptera: Evaniidae: Afrevania and Trissevania).

We revise two relatively rare ensign wasp genera, whose species are restricted to Sub-Saharan Africa: Afrevania and Trissevania. Afrevania longipetiolata sp. nov., Trissevania heatherae sp. nov., T. hugoi sp. nov., T. mrimaensis sp. nov. and T. slideri sp. nov. are described, males and females of T. anemotis and Afrevania leroyi are redescribed, and an identification key for Trissevaniini is provided. We argue that Trissevania mrimaensis sp. nov. and T. heatherae sp. nov. populations are vulnerable, given their limited distributions and threats from mining activities in Kenya. We hypothesize that these taxa together comprise a monophyletic lineage, Trissevaniini, tr. nov., the members of which share the ability to fold their fore wings along two intersecting fold lines. Although wing folding of this type has been described for the hind wing of some insects four-plane wing folding of the fore wing has never been documented. The wing folding mechanism and the pattern of wing folds of Trissevaniini is shared only with some cockroach species (Blattodea). It is an interesting coincidence that all evaniids are predators of cockroach eggs. The major wing fold lines of Trissevaniini likely are not homologous to any known longitudinal anatomical structures on the wings of other Evaniidae. Members of the new tribe share the presence of a coupling mechanism between the fore wing and the mesosoma that is composed of a setal patch on the mesosoma and the retinaculum of the fore wing. While the setal patch is an evolutionary novelty, the retinaculum, which originally evolved to facilitate fore and hind wing coupling in Hymenoptera, exemplifies morphological exaptation. We also refine and clarify the Semantic Phenotype approach used in previous taxonomic revisions and explore the consequences of merging new with existing data. The way that semantic statements are formulated can evolve in parallel, alongside improvements to the ontologies themselves.

A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin

Recent fossil discoveries have substantially reduced the morphological gap between non-avian and avian dinosaurs, yet avians including Archaeopteryx differ from non-avian theropods in their limb proportions. In particular, avians have proportionally longer and more robust forelimbs that are capable of supporting a large aerodynamic surface. Here we report on a new maniraptoran dinosaur, Anchiornis huxleyi gen. et sp. nov., based on a specimen collected from lacustrine deposits of uncertain age in western Liaoning, China. With an estimated mass of 110 grams, Anchiornis is the smallest known non-avian theropod dinosaur. It exhibits some wrist features indicative of high mobility, presaging the wing-folding mechanisms seen in more derived birds and suggesting rapid evolution of the carpus. Otherwise, Anchiornis is intermediate in general morphology between non-avian and avian dinosaurs, particularly with regard to relative forelimb length and thickness, and represents a transitional step toward the avian condition. In contrast with some recent comprehensive phylogenetic analyses, our phylogenetic analysis incorporates subtle morphological variations and recovers a conventional result supporting the monophyly of Avialae.

Dermaptera hindwing structure and folding: New evidence for familial, ordinal and superordinal relationships within Neoptera (Insecta)

The Dermaptera are a small order of insects, marked by reduced forewings, hindwings with a unique and complicated folding pattern, and by pincer-like cerci. Hindwing characters of 25 extant dermapteran species are documented. The highly derived hindwing venation and articulation is accurately homologized with the other pterygote orders for the first time. The hindwing base of Dermaptera contains phylogenetically informative characters. They are compared with their homologues in fossil dermapteran ancestors, and in Plecoptera, Orthoptera (Caelifera), Dictyoptera (Mantodea, Blattodea, Isoptera), Fulgoromorpha and Megaloptera. A fully homologized character matrix of the pterygote wing complex is offered for the first time. The wing venation of the Coleoptera is re-interpreted and slightly modified. The all-pterygote character analysis suggests the following relationships: Pterygota: Palaeoptera + Neoptera; Neoptera: [Pleconeoptera + Orthoneoptera] + [Blattoneoptera + (Hemineoptera + Endoneoptera)]. Blattoneoptera share at least 15 wing apomorphies with the sistergroup Hemineoptera + Endoneoptera and none with the Orthoneoptera and Pleconeoptera; Blattoneoptera: (Grylloblattodea + (Dermaptera + Dictyoptera)); Dictyoptera: (Mantodea + (Blattodea + Isoptera). Dermaptera share 13 wing apomorphies with the sistergroup Dictyoptera. In order to document the intra-ordinal relationships of Dermaptera, 18 new characters of venation and articulation are added to an existing data set and analyzed cladistically. The following relationships are suggested (43 characters, tree length 72, CI 0.819 and RI 0.935). Dermaptera: Karschiellidae + (Diplatyidae + (Pygidicranidae + (Allostethus indicum + (Anisolabididae + (Labiduridae + [Forficulidae + (Chelisochidae + Spongiphoridae)]))))). The taxa in quotation marks are probably paraphyletic. Fossil Dermaptera and Protelytroptera show that wing-folding characters were already present in Permian ancestors. The evolution of the dermapteran wing-folding mechanism is discussed and the hindwing is presented as a working origami model, which will fold as in living earwigs. The functional role of the wing base in wing folding is examined. Characters in orders and other higher taxa are not independent and cannot be analyzed out of context with their groundplans. Higher systematics is dealing with diametrally different problems than species-level systematics. The necessity of using a different methodology for species-level and higher-level phylogenetics is discussed and recommendations are made.

Wing folding and the functional morphology of the wing base in Coleoptera

The wing unfolding of Pachnoda marginata was examined using digital video (50 half-fps) and high speed video sequences (1000 fps), and the skeleto-muscular apparatus of the metathorax was described. Left and right hind wing are able to promote independently of each other. The hind wings do not unfold instantly when the elytra are lifted and may also reach the flight position (and beat) while still folded. Wing promotion is exhaustible and the time needed for unfolding varies considerably. These observations strongly suggest a muscular control. Wing unfolding is probably triggered by contraction of M. pleura alaris and a resulting proximad movement of the 3rd axillary sclerite, pulling the Media posterior backwards, while the Radius anterior is held by the basalar muscle as the antagonist. Our findings are in clear contrast to the earlier assumption that the hind wings of Coleoptera either unfold or fold due to intrinsic elasticity. The specific wing folding and unfolding mechanisms are autapomorphic character states of Coleoptera. They were maintained during evolution even though considerable variations of skeletal thoracic structures, musculature and venation occurred. (Additional material is available from the Zoology web page: http://www.urbanfischer.de/journals/zoology).

Phylogenetic Relationships of the Suborders of Coleoptera (Insecta).

One hundred seven external and internal characters of larval and adult representatives of 28 genera of the coleopteran suborders were analyzed cladistically. Four groups of Neuropterida were introduced as outgroup. The analysis yielded 18 trees with a minimum of 194 steps (CI 0.691). All trees support the monophyly of all four suborders and a branching pattern (Archostemata + (Adephaga + (Myxophaga + Polyphaga))). The presence of elytra with meso- and metathoracic locking devices, the specific hind-wing folding, the close connection of exposed sclerites, the absence of the mera, the absence of eight thoracic muscles, the reduced abdominal sternite I, and the invagination of terminal segments are autapomorphies of Coleoptera. The monophyly of Coleoptera excl. Archostemata is supported by further transformations of the thoracic sclerites such as absence of the mesothoracic discriminal line and katepisternal joint, by an internalized or absent metathoracic trochantin, by the presence of a bending zone in the hind-wing, and by eight further muscle losses. Fusion of tibia and tarsus and presence of a single claw are larval synapomorphies of Myxophaga and Polyphaga. Adults are characterized by fusion of protrochantin and propleura and by the rigid connection of the meso- and metathoracic ventrites. The eucinetoid lineage of Polyphaga is characterized by the secondary absence of the bending zone of the alae. This results in a distinctly simplified wing folding mechanism. The monophyly of Cucujiformia (+ Bostrichoidea) is supported by the presence of cryptonephric Malpighian tubules. Transformations of fore-and hind-wings, reinforcement and simplification of the thoracic exoskeleton, and an efficient use of a distinctly reduced set of thoracic muscles play an important role in the early evolution of Coleoptera. Many different larval character transformations take place in the earlier Mesozoic within the suborders.

Phylogenetic Relationships of the Suborders of Coleoptera (Insecta)

One hundred seven external and internal characters of larval and adult representatives of 28 genera of the coleopteran suborders were analyzed cladistically. Four groups of Neuropterida were introduced as outgroup. The analysis yielded 18 trees with a minimum of 194 steps (CI 0.691). All trees support the monophyly of all four suborders and a branching pattern (Archostemata + (Adephaga + (Myxophaga + Polyphaga))). The presence of elytra with meso- and metathoracic locking devices, the specific hind-wing folding, the close connection of exposed sclerites, the absence of the mera, the absence of eight thoracic muscles, the reduced abdominal sternite I, and the invagination of terminal segments are autapomorphies of Coleoptera. The monophyly of Coleoptera excl. Archostemata is supported by further transformations of the thoracic sclerites such as absence of the mesothoracic discriminal line and katepisternal joint, by an internalized or absent metathoracic trochantin, by the presence of a bending zone in the hind-wing, and by eight further muscle losses. Fusion of tibia and tarsus and presence of a single claw are larval synapomorphies of Myxophaga and Polyphaga. Adults are characterized by fusion of protrochantin and propleura and by the rigid connection of the meso- and metathoracic ventrites. The eucinetoid lineage of Polyphaga is characterized by the secondary absence of the bending zone of the alae. This results in a distinctly simplified wing folding mechanism. The monophyly of Cucujiformia (+ Bostrichoidea) is supported by the presence of cryptonephric Malpighian tubules. Transformations of fore-and hind-wings, reinforcement and simplification of the thoracic exoskeleton, and an efficient use of a distinctly reduced set of thoracic muscles play an important role in the early evolution of Coleoptera. Many different larval character transformations take place in the earlier Mesozoic within the suborders.

Asymmetrical colour and wing-folding inTithrone roseipennis(Saussure 1870) a neotropical praying mantis (Mantodea Hymenopodidae)

The frequency and type of forewing colour asymmetry present in Tithrone roseipennis (Saussure 1870) (Mantodea Hymenopodidae) was examined and 29 out of 35 specimens had red/green forewing colour asymmetry. The insects, from both field-collected material and museum specimens, contained both left and right fore wing asymmetry morphs. This colour asymmetry was found to be linked to wing-folding. Asymmetrical mantids always appeared cryptically green at rest, decreasing the chance of predator detection. It is suggested that red and green colour pigments are genetically encoded for, and genetic epistatic interactions result between forewing colouration and wing folding mechanisms. The forewing colouration of T. roseipennis is an example of antisymmetry.

EVOLUTION OF THE HIND WING IN COLEOPTERA

AbstractA survey is made of the major features of the venation, articulation, and folding in the hind wings of Coleoptera. The documentation is based upon examination of 108 Coleoptera families and 200 specimens, and shown in 101 published figures. Wing veins and articular sclerites are homologized with elements of the neopteran wing groundplan, resulting in wing vein terminology that differs substantially from that generally used by coleopterists. We tabulate the differences between currently used venational nomenclature and the all-pterygote homologous symbols. The use of the neopteran groundplan, combined with the knowledge of the way in which veins evolved, provides many strong characters linked to the early evolutionary radiation of Coleoptera. The order originated with the development of the apical folding of the hind wings under the elytra executed by the radial and medial loop. The loops, which are very complex venational structures, further diversified in four distinctly different ways which mark the highest (suborder) taxa. The remaining venation and the wing articulation have changed with the loops, which formed additional synapomorphies and autapomorphies at the suborder, superfamily, and sometimes even family and tribe levels. Relationships among the four currently recognized suborders of Coleoptera are reexamined using hind wing characters. The number of wing-related apomorphies are 16 in Coleoptera, seven in Archostemata + Adephaga–Myxophaga, four in Adephaga–Myxophaga, seven in Myxophaga, nine in Archostemata, and five in Polyphaga. The following phylogenetic scheme is suggested: Polyphaga [Archostemata (Adephaga + Myxophaga)]. Venational evidence is given to define two major lineages (the hydrophiloid and the eucinetoid) within the suborder Polyphaga. The unique apical wing folding mechanism of beetles is described. Derived types of wing folding are discussed, based mainly on a survey of recent literature. A sister group relationship between Coleoptera and Strepsiptera is supported by hind wing evidence.