Wing Folding Research Articles

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.

The hydraulic mechanism of the unfolding of hind wings in Dorcus titanus platymelus (order: Coleoptera).

In most beetles, the hind wings are thin and fragile; when at rest, they are held over the back of the beetle. When the hind wing unfolds, it provides the necessary aerodynamic forces for flight. In this paper, we investigate the hydraulic mechanism of the unfolding process of the hind wings in Dorcus titanus platymelus (Oder: Coleoptera). The wing unfolding process of Dorcus titanus platymelus was examined using high speed camera sequences (400 frames/s), and the hydraulic pressure in the veins was measured with a biological pressure sensor and dynamic signal acquisition and analysis (DSA) during the expansion process. We found that the total time for the release of hydraulic pressure during wing folding is longer than the time required for unfolding. The pressure is proportional to the length of the wings and the body mass of the beetle. A retinal camera was used to investigate the fluid direction. We found that the peak pressures correspond to two main cross-folding joint expansions in the hind wing. These observations strongly suggest that blood pressure facilitates the extension of hind wings during unfolding.

Wing load investigation of the plunge-diving locomotion of a gannet Morus inspired submersible aircraft

In this paper, we studied the wing root pivot joint’s radial load of a submersible airplane which imitates the locomotion of gannet’s Morus plunge-diving, by implementing a test device name Mimic-Gannet. The housing of the device was designed by mimicking the morphology of a living gannet, and the folding wings were realized by the mechanism of variable swept back wing. Then, the radial loads of the wing root were obtained under the conditions of different dropping heights, different sweptback angles and different water-entry inclination angles (i.e., the angle between the longitudinal body axis and the water surface), and the relationships between the peak radial load and the above three parameters were analyzed and discussed respectively. In the studied areas, the minimum peak radial load of the pivot joint is 50.93 N, while the maximum reaches up to 1135.00 N. The largest peak load would be generated for the situation of vertical water entry and zero wing sweptback angle. And it is of great significance to choose the three parameters properly to reduce the pivot joint’s radial load, i.e., larger wing sweptback angle, smaller dropping height and water-entry inclination angle. It is also concluded that the peak radial load on the wing root is closely linear with the water-entry dropping height and the wing sweptback angle with a significant correlation. Eventually, the relationship between the wing load and the dropping height, water-entry inclination angle or wing sweptback angle, could be used to calculate the wing load about plunge-diving of a submersible aircraft, and the conclusions reveal the wing load characteristic of the gannet’s plunge process for the biologists.

K19100 ハイスピードカメラを用いた昆虫の翅の展開・収納挙動の解析と展開構造物への応用([K19100],宇宙工学部門)

Artful wing folding of insects has attracted the interest of aerospace engineering scientists as well as entomologists. Foldable hindwings are the ultimate deployable structures. They have sufficient strength and stiffness to tolerate 20-1000 beats per second in the flight position, although they can be folded and unfolded instantly depending on the situation. Entomologists point out that insect wings can be classified into the following two groups based on structural characteristics: folding-stable type and unfolding-stable type. In each group, the movement toward a stable point is easy to achieve because it can be triggered by a small force and progresses automatically by elastic force. Naturally, problems are observed mainly in reverse-directed movements that require a larger force to cross the peak of elastic energy. Some insects address these problems by unique and somewhat heavy-handed methods. Despite large potential for engineering application, few studies have been undertaken to reveal these characteristic movements. This study used a high-speed camera to observe the folding and unfolding movements of some beetles. The revealed folding/unfolding mechanisms can achieve not only highly compact wing storage but also immediate deployment/folding. They offer significant potential for space deployable structures.

Design of a Foldable Flapping Mechanism

Folding motion is important for a flight creature using flapping wing mode, but it seldom used for flapping-wing robot. In this paper, we propose a new foldable flapping wing mechanism, which consists of spatial crank-rocker mechanism, parallelogram mechanism, and cam mechanism. We establish the kinematical models, calculate the optimal parameters, and set up the virtual prototype using 3D software. The tracks of wingtip and the comparison between foldable and unfoldable flap wing show that folding motion can improve lift force obviously.

Gain self-scheduled H∞ control for morphing aircraft in the wing transition process based on an LPV model

This article investigates gain self-scheduled H∞ robust control system design for a tailless folding-wing morphing aircraft in the wing shape varying process. During the wing morphing phase, the aircraft’s dynamic response will be governed by time-varying aerodynamic forces and moments. Nonlinear dynamic equations of the morphing aircraft are linearized by using Jacobian linearization approach, and a linear parameter varying (LPV) model of the morphing aircraft in wing folding is obtained. A multi-loop controller for the morphing aircraft is formulated to guarantee stability for the wing shape transition process. The proposed controller uses a set of inner-loop gains to provide stability using classical techniques, whereas a gain self-scheduled H∞ outer-loop controller is devised to guarantee a specific level of robust stability and performance for the time-varying dynamics. The closed-loop simulations show that speed and altitude vary slightly during the whole wing folding process, and they converge rapidly after the process ends. This proves that the gain self-scheduled H∞ robust controller can guarantee a satisfactory dynamic performance for the morphing aircraft during the whole wing shape transition process. Finally, the flight control system’s robustness for the wing folding process is verified according to uncertainties of the aerodynamic parameters in the nonlinear model.

Flutter Characteristics of a Morphing Flight Vehicle with Varying Inboard and Outboard Folding Angles

Morphing aircraft capable of varying their wing form can operate efficiently at various flight conditions. However, radical morphing of the aircraft leads to increased structural complexities, resulting in occurrence of dynamic instabilities such as flutter, which can lead to catastrophic events. Therefore, it is of utmost importance to investigate and understand the changes in flutter characteristics of morphing wings, to ensure uncompromised safety and maximum reliability. In this paper, a study on the flutter characteristics of the folding wing type morphing concept is conducted, to examine the effect of changes in folding angles on the flutter speed and flutter frequency. The subsonic aerodynamic theory Doublet Lattice Method (DLM) and p-k method are used, to perform the flutter analysis in MSC.NASTRAN. The present baseline flutter characteristics correspond well with the results from previous study. Furthermore, enhancement of the flutter characteristics of an aluminum folding wing is proposed, by varying the outboard wing folding angle independently of the inboard wing folding angle. It is clearly found that the flutter characteristics are strongly influenced by changes in the inboard/outboard folding angles, and significant improvement in the flutter characteristics of a folding wing can be achieved, by varying its outboard wing folding angle.

Localised JAK/STAT Pathway Activation Is Required for Drosophila Wing Hinge Development

Extensive morphogenetic remodelling takes place during metamorphosis from a larval to an adult insect body plan. These changes are particularly intricate in the generation of the dipteran wing hinge, a complex structure that is derived from an apparently simple region of the wing imaginal disc. Using the characterisation of original outstretched alleles of the unpaired locus as a starting point, we demonstrate the role of JAK/STAT pathway signalling in the process of wing hinge development. We show that differences in JAK/STAT signalling within the proximal most of three lateral folds present in the wing imaginal disc is required for fold morphology and the subsequent differentiation of the first and second auxiliary sclerites as well as the posterior notal wing process. Changes in these domains are consistent with the established fate map of the wing disc. We show that outstretched wing posture phenotypes arise from the loss of a region of Unpaired expression in the proximal wing fold and demonstrate that this results in a decrease in JAK/STAT pathway activity. Finally we show that reduction of JAK/STAT pathway activity within the proximal wing fold is sufficient to phenocopy the outstretched phenotype. Taken together, we suggest that localised Unpaired expression and hence JAK/STAT pathway activity, is required for the morphogenesis of the adult wing hinge, providing new insights into the link between signal transduction pathways, patterning and development.

Folding Angle Measurement and Control Technology of Deformable UAV

The deformable UAV has the advantage over the traditional fixed-wing aircraft in expanding the flight envelope. In this paper, a folding wing mechanism is designed to meet the accurate angle control requirement. Accordingly, an angle measurement method based on MEMS (micro-electromechanical systems) accelerometers is studied. The accurate folding angle in any condition can be derived from analysis of the folding wing’s acceleration in different positions, upon which the fuzzy control law of the wing’s folding angle is proposed. Finally, the validity and accuracy of the algorithm is verified with experiment. DOI: http://dx.doi.org/10.11591/telkomnika.v11i4.2345

Design and characterization of a multi-articulated robotic bat wing

There are many challenges to measuring power input and force output from a flapping vertebrate. Animals can vary a multitude of kinematic parameters simultaneously, and methods for measuring power and force are either not possible in a flying vertebrate or are very time and equipment intensive. To circumvent these challenges, we constructed a robotic, multi-articulated bat wing that allows us to measure power input and force output simultaneously, across a range of kinematic parameters. The robot is modeled after the lesser dog-faced fruit bat, Cynopterus brachyotis, and contains seven joints powered by three servo motors. Collectively, this joint and motor arrangement allows the robot to vary wingbeat frequency, wingbeat amplitude, stroke plane, downstroke ratio, and wing folding. We describe the design, construction, programing, instrumentation, characterization, and analysis of the robot. We show that the kinematics, inputs, and outputs demonstrate good repeatability both within and among trials. Finally, we describe lessons about the structure of living bats learned from trying to mimic their flight in a robotic wing.

The Angle Measurement of Folding Wing Craft Based on MEMS

The unmanned folding wing aircraft has the advantage on expanding the flight envelope. The angle measurement algorithm of folding wing craft which based on MEMS (micro-electromechanical systems) accelerometers was studied. Collected the acceleration values from the accelerometers, and built the motion parameter model .Used the analyze data and the redundant acceleration; multiple sensors were used to do the error correction. With the experiment of folding wing, the validity and accuracy of the algorithm was verified.

Aeroelastic Behavior of Morphing Wing in Flutter Regions

A morphing of a system is capable of changing the shape from the cruise to dash configurations. During the motion, the aerodynamic and structural characteristics can be varied tremendously, and the new shape will induce the different aeroelastic stability behavior. Thus, the purpose of this study is to investigate the flutter analysis of the folding wing structure including the effect of various parameters such as fold angles et al. of the composite laminates structures. For doing this these works, the aero-elastic analysis of folding wing is performed with respect to the parameters using PK method. Also, Finite Element Method is used in structural analysis, and Doublet Lattice Method is applied in aerodynamic analysis. Generally, the dynamic pressure and frequency during the flutter are sensitive to the structural characteristic, thus the flutter mode alteration is occurred by changed natural frequencies. Also, the alteration causes the flutter dynamic pressure variation. Therefore, results represent the aeroelastic stability variation due to the folding wing system including the effects of ply angles of composite laminates.

Improved Design and Dynamic Simulation of High Aspect Ratio Folding Wings

Folding wings of UAV may lead to high bending and torsion deformation under flight load. In order to solve the problem, an improved folding wing mechanism is proposed, which makes support mechanism stiffness become enough big. By means of CATIA and ADAMS, a virtual prototype is set up, which can simulate dynamics of the deployment mechanism. Therefore the relationship among deployment time and friction coefficient and tension is arrived. Meanwhile finite element analysis is made on folding wing with support structure and without support structure by MSC.Nastran. And the results show that the stiffness and strength change obviously. Simulation results have a certain guiding significance for practical engineering application.

Simulation Research of the Unfolding Process for UAV Folding Wings Based on CATIA and ADAMS

Simulation Research of the Unfolding Process for UAV Folding Wings Based on CATIA and ADAMS

Aeroelastic Model of Multisegmented Folding Wings: Theory and Experiment

Morphing-wing research has garnered much attention in the aerospace community over the last decade, and the folding wing is a promising concept that can improve aircraft performance over multiple types of missions. Several high-fidelity analyses of folding-wing aeroelastic stability have been published, but most analyses are specifi ct o certain wing planforms or a fixed number of wing segments. This paper presents a general aeroelastic model that predicts the flutter speed and flutter frequency of a folding wing with simplified geometry but with an arbitrary numberof wingsegments. Thebeam-theory structuralmodelandthe strip-theoryunsteadyaerodynamic modelare coupled using Lagrange’s equations. Three experimental models are constructed, and flutter tests are performed over a wide range of fold angles. The theoretical predictions for flutter speeds are within 10% of experimentally measured values for most configurations. In general, the results show that the essential physics of the problem is captured by the present first-principles model. Furthermore, data show that increasing the fold angle causes up to 30% increase in flutter speed, which has applications in extending the flutter boundaries of morphing aircraft.

Development of the weight formula for a folding wing

The classification of methods for carrier-based aircraft wing folding is presented. We determined the factors influencing the folding axis position and the mass increase of the wing being folded. We also suggested a technique of deriving the folding wing mass formula by an example of the wing rotation around the axis, which is parallel to the aircraft plane of symmetry.

Large Displacement Flexible Micro Actuators

This paper discusses a major application of flexible micro actuators in Micro Air Vehicles (MAV). Design, Kinematics, flapping patterns, performance tests of flapping wing mechanism which replicates dragonfly and corresponding results are discussed in this paper. This paper also discusses artificial foldable wing models by mimicking the unfolding/folding of beetle hind wing in which the actuation is triggered by electrically activated Shape Memory Alloy (SMA) wires.

2A1-H08 多関節機構の冗長性を利用した展開収納機能をもつ全翼式の小型無人飛行機(飛行ロボット・メカトロニクス(1))

Aim of this research is development of a Micro unmanned vehicle (MUAV) named "Ptera Pod" to survey Mt. Mihara volcanic field in Izu-Oshima. These are assumed that agencies or volcano researchers to use at the time of the eruption. The fact is that the volcanic field have very strong wind, so that it is hard for operator to carry, assemble and fly MUAV in this situation. Ptera Pod is folding wing plane with one-dimensional mulch-joint redundancy mechanism, and also it is flying wing form. It is declared by field test in Ura-Sabaku of Izu-Oshima, these features make it easy, fast and safe to prepare the flight and control under strong wind condition around 10m/s. From the results, we confirmed that the flight onboard camera got HD movies about surfaces around the field successfully.

Structural Dynamics Model of Multisegmented Folding Wings: Theory and Experiment

Morphing wing research has garnered much attention in the aerospace community over the last decade, and the folding wing is a promising concept that can improve aircraft performance over multiple types of missions. Several high-fidelity analyses of folding wing structural dynamics have been published, but most analyses are specifi ct o certain wing planforms or a fixed number of wing segments. This paper presents a general structural dynamics modelthatpredictsthenaturalfrequencies ofafoldingwingwithsimplifiedgeometry butwithanarbitrary number of wing segments. The model is derived using beam theory and component modal analysis: the energy expressions and constraint equations are derived from kinematics, and the equations of motion are derived using Lagrange’s equations with Lagrange multipliers. Three experimental models are constructed, and the natural frequencies are measured over a wide range of fold angles. The agreement between theory and experiment is within 10% for most data points. The results agree well with trends from existing work, and the model can be used to study the structural dynamics behavior of folding wings as well as similar multibody systems.

Experimental In-Flight Rolling MAV Wing Deployment and Aerodynamic Characterization

The deployment dynamics of a tape-spring style, folding MAV wing in flight are complicated and an investigation is made using wind tunnel testing. High speed photography is used to characterize the deployment motion of the wing while a force balance records six- axis aerodynamic loading of the model. An in-flight deployment of a folding wing would be advantageous after an autonomous tube launch, however the dynamics are potentially problematic due to buckling. Steady state aerodynamics of prototype tube-launch MAVs are characterized for both rigid body and compliant, rolling wings. Aerodynamic phenomena associated with the significant relative body size are identified. Wing deployments are demonstrated at four different angles-of-attack at single velocity, while an extreme case deployment is shown at a high velocity. Two-piece cylindrical shells are used to retain the wing prior to deployment and are released by hot-wire cutting of retaining lines. Three phenomena leading improper deployment are noted. Aeroelastic flutter is observed and characterized after the wing deployment at certain conditions.