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Artykuły w czasopismach na temat "Scale Flapping Wings"
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Hawkes, Elliot W., i David Lentink. "Fruit fly scale robots can hover longer with flapping wings than with spinning wings". Journal of The Royal Society Interface 13, nr 123 (październik 2016): 20160730. http://dx.doi.org/10.1098/rsif.2016.0730.
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Hovering flies generate exceptionally high lift, because their wings generate a stable leading edge vortex. Micro flying robots with a similar wing design can generate similar high lift by either flapping or spinning their wings. While it requires less power to spin a wing, the overall efficiency depends also on the actuator system driving the wing. Here, we present the first holistic analysis to calculate how long a fly-inspired micro robot can hover with flapping versus spinning wings across scales. We integrate aerodynamic data with data-driven scaling laws for actuator, electronics and mechanism performance from fruit fly to hummingbird scales. Our analysis finds that spinning wings driven by rotary actuators are superior for robots with wingspans similar to hummingbirds, yet flapping wings driven by oscillatory actuators are superior at fruit fly scale. This crossover is driven by the reduction in performance of rotary compared with oscillatory actuators at smaller scale. Our calculations emphasize that a systems-level analysis is essential for trading-off flapping versus spinning wings for micro flying robots.
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Meresman, Yonatan, i Gal Ribak. "Allometry of wing twist and camber in a flower chafer during free flight: How do wing deformations scale with body size?" Royal Society Open Science 4, nr 10 (październik 2017): 171152. http://dx.doi.org/10.1098/rsos.171152.
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Intraspecific variation in adult body mass can be particularly high in some insect species, mandating adjustment of the wing's structural properties to support the weight of the larger body mass in air. Insect wings elastically deform during flapping, dynamically changing the twist and camber of the relatively thin and flat aerofoil. We examined how wing deformations during free flight scale with body mass within a species of rose chafers (Coleoptera: Protaetia cuprea ) in which individuals varied more than threefold in body mass (0.38–1.29 g). Beetles taking off voluntarily were filmed using three high-speed cameras and the instantaneous deformation of their wings during the flapping cycle was analysed. Flapping frequency decreased in larger beetles but, otherwise, flapping kinematics remained similar in both small and large beetles. Deflection of the wing chord-wise varied along the span, with average deflections at the proximal trailing edge higher by 0.2 and 0.197 wing lengths compared to the distal trailing edge in the downstroke and the upstroke, respectively. These deflections scaled with wing chord to the power of 1.0, implying a constant twist and camber despite the variations in wing and body size. This suggests that the allometric growth in wing size includes adjustment of the flexural stiffness of the wing structure to preserve wing twist and camber during flapping.
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Malhan, Ria, Moble Benedict i Inderjit Chopra. "Experimental Studies to Understand the Hover and Forward Flight Performance of a MAV-Scale Flapping Wing Concept". Journal of the American Helicopter Society 57, nr 2 (1.04.2012): 1–11. http://dx.doi.org/10.4050/jahs.57.022003.
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Systematic experimental studies were performed to understand the role of two key degrees of freedom, flapping and pitching, in aerodynamic performance of a flapping wing, in both hover and forward flight. Required flapping kinematics is prescribed mechanically, and dynamic pitching/twisting is obtained passively using inertial and aerodynamic forces. Forces produced by the wing are measured at the root using a six-component balance at different flapping frequencies, flapping/pitching amplitudes, and wind speeds. The results clearly show that maximum average thrust over a flap cycle in hover can be achieved using symmetric, high amplitude passive pitching. However, in forward flight, optimum aerodynamic performance (lift and propulsive thrust) is obtained using asymmetric wing pitching with low pitching amplitudes. Furthermore, dynamic twisting (obtained using flexible wings), instead of dynamic pitching, produces better performance in forward flight due to spanwise and temporal modulation of the wing pitch angle. Pure flapping (no pitching) of rigid wings in forward flight at high reduced frequencies and high pitch angles produces a threefold increase in lift coefficient over static values. Maximum average propulsive thrust over a flap cycle in forward flight is obtained using symmetric pitching. To produce high values of both, average lift and thrust, an asymmetry in kinematics along with pitching is required in forward flight. This can be achieved either through asymmetric pitching of rigid wings or dynamic twisting of torsionally flexible wings.
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Goszczyński, Jacek A., Maciej Lasek, Józef Pietrucha i Krzysztof Sibilski. "ANIMALOPTERS-TOWARDS A NEW DIMENSION OF FLIGHT MECHANICS". TRANSPORT 17, nr 3 (30.06.2002): 108–16. http://dx.doi.org/10.3846/16483840.2002.10414023.
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Recently, it has been recognised that flapping wing propulsion can be more efficient than conventional propellers if applied to very small-scale vehicles, so-called MAVs (micro air vehicles). Extraordinary possibilities of such objects, particularly in the context of special missions, are discussed. Flapping flight is more complicated than flight with fixed or rotating wings. Therefore, there is a need to understand the mechanisms of force generation by flapping wings in a more comprehensive way. The paper describes the current work on flapping wing conducted by the Flying amp;Swimming Puzzle Group. The key to understand the mechanisms of flapping flight is the adequate physical and mathematical modelling; modelling problems of flow and motion are emphasised. Sample calculations illustrating current capabilities of the method have been performed. The effect of feathering amplitude, flapping amplitude, and phase shifting on the MAV&s control effectiveness has been examined. It has been discovered that the parameters mentioned above can be considered as control parameters of “flapping wing” MAVs, especially in lateral direction. Research programmes for the construction of MAYs concentrate on understanding the mechanisms of animal flight and on creating smart structures which would enable flight in micro-scale.
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Chen, Yufeng, Cathleen Arase, Zhijian Ren i Pakpong Chirarattananon. "Design, Characterization, and Liftoff of an Insect-Scale Soft Robotic Dragonfly Powered by Dielectric Elastomer Actuators". Micromachines 13, nr 7 (18.07.2022): 1136. http://dx.doi.org/10.3390/mi13071136.
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Dragonflies are agile and efficient flyers that use two pairs of wings for demonstrating exquisite aerial maneuvers. Compared to two-winged insects such as bees or flies, dragonflies leverage forewing and hindwing interactions for achieving higher efficiency and net lift. Here we develop the first at-scale dragonfly-like robot and investigate the influence of flapping-wing kinematics on net lift force production. Our 317 mg robot is driven by two independent dielectric elastomer actuators that flap four wings at 350 Hz. We extract the robot flapping-wing kinematics using a high-speed camera, and further measure the robot lift forces at different operating frequencies, voltage amplitudes, and phases between the forewings and hindwings. Our robot achieves a maximum lift-to-weight ratio of 1.49, and its net lift force increases by 19% when the forewings and hindwings flap in-phase compared to out-of-phase flapping. These at-scale experiments demonstrate that forewing–hindwing interaction can significantly influence lift force production and aerodynamic efficiency of flapping-wing robots with passive wing pitch designs. Our results could further enable future experiments to achieve feedback-controlled flights.
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Shyy, Wei, Chang-kwon Kang, Pakpong Chirarattananon, Sridhar Ravi i Hao Liu. "Aerodynamics, sensing and control of insect-scale flapping-wing flight". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, nr 2186 (luty 2016): 20150712. http://dx.doi.org/10.1098/rspa.2015.0712.
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There are nearly a million known species of flying insects and 13 000 species of flying warm-blooded vertebrates, including mammals, birds and bats. While in flight, their wings not only move forward relative to the air, they also flap up and down, plunge and sweep, so that both lift and thrust can be generated and balanced, accommodate uncertain surrounding environment, with superior flight stability and dynamics with highly varied speeds and missions. As the size of a flyer is reduced, the wing-to-body mass ratio tends to decrease as well. Furthermore, these flyers use integrated system consisting of wings to generate aerodynamic forces, muscles to move the wings, and sensing and control systems to guide and manoeuvre. In this article, recent advances in insect-scale flapping-wing aerodynamics, flexible wing structures, unsteady flight environment, sensing, stability and control are reviewed with perspective offered. In particular, the special features of the low Reynolds number flyers associated with small sizes, thin and light structures, slow flight with comparable wind gust speeds, bioinspired fabrication of wing structures, neuron-based sensing and adaptive control are highlighted.
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Yang, Xuan, Aswathi Sudhir, Atanu Halder i Moble Benedict. "Nonlinear Aeroelastic Analysis for Highly Flexible Flapping Wing in Hover". Journal of the American Helicopter Society 67, nr 2 (1.04.2022): 1–15. http://dx.doi.org/10.4050/jahs.67.022002.
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Aeromechanics of highly flexible flapping wings is a complex nonlinear fluid–structure interaction problem and, therefore, cannot be analyzed using conventional linear aeroelasticity methods. This paper presents a standalone coupled aeroelastic framework for highly flexible flapping wings in hover for micro air vehicle (MAV) applications. The MAV-scale flapping wing structure is modeled using fully nonlinear beam and shell finite elements. A potential-flow-based unsteady aerodynamic model is then coupled with the structural model to generate the coupled aeroelastic framework. Both the structural and aerodynamic models are validated independently before coupling. Instantaneous lift force and wing deflection predictions from the coupled aeroelastic simulations are compared with the force and deflection measurements (using digital image correlation) obtained from in-house flapping wing experiments at both moderate (13 Hz) and high (20 Hz) flapping frequencies. Coupled trim analysis is then performed by simultaneously solving wing response equations and vehicle trim equations until trim controls, wing elastic response, inflow and circulation converge all together. The dependence of control inputs on weight and center of gravity (cg) location of the vehicle is studied for the hovering flight case.
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WHITNEY, J. P., i R. J. WOOD. "Aeromechanics of passive rotation in flapping flight". Journal of Fluid Mechanics 660 (27.07.2010): 197–220. http://dx.doi.org/10.1017/s002211201000265x.
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Flying insects and robots that mimic them flap and rotate (or ‘pitch’) their wings with large angular amplitudes. The reciprocating nature of flapping requires rotation of the wing at the end of each stroke. Insects or flapping-wing robots could achieve this by directly exerting moments about the axis of rotation using auxiliary muscles or actuators. However, completely passive rotational dynamics might be preferred for efficiency purposes, or, in the case of a robot, decreased mechanical complexity and reduced system mass. Herein, the detailed equations of motion are derived for wing rotational dynamics, and a blade-element model is used to supply aerodynamic force and moment estimates. Passive-rotation flapping experiments with insect-scale mechanically driven artificial wings are conducted to simultaneously measure aerodynamic forces and three-degree-of-freedom kinematics (flapping, rotation and out-of-plane deviation), allowing a detailed evaluation of the blade-element model and the derived equations of motion. Variations in flapping kinematics, wing-beat frequency, stroke amplitude and torsional compliance are made to test the generality of the model. All experiments showed strong agreement with predicted forces and kinematics, without variation or fitting of model parameters.
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Chen, Yufeng, Nick Gravish, Alexis Lussier Desbiens, Ronit Malka i Robert J. Wood. "Experimental and computational studies of the aerodynamic performance of a flapping and passively rotating insect wing". Journal of Fluid Mechanics 791 (15.02.2016): 1–33. http://dx.doi.org/10.1017/jfm.2016.35.
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Flapping wings are important in many biological and bioinspired systems. Here, we investigate the fluid mechanics of flapping wings that possess a single flexible hinge allowing passive wing pitch rotation under load. We perform experiments on an insect-scale (${\approx}1$ cm wing span) robotic flapper and compare the results with a quasi-steady dynamical model and a coupled fluid–structure computational fluid dynamics model. In experiments we measure the time varying kinematics, lift force and two-dimensional velocity fields of the induced flow from particle image velocimetry. We find that increasing hinge stiffness leads to advanced wing pitching, which is beneficial towards lift force production. The classical quasi-steady model gives an accurate prediction of passive wing pitching if the relative phase difference between the wing stroke and the pitch kinematics,${\it\delta}$, is small. However, the quasi-steady model cannot account for the effect of${\it\delta}$on leading edge vortex (LEV) growth and lift generation. We further explore the relationships between LEV, lift force, drag force and wing kinematics through experiments and numerical simulations. We show that the wing kinematics and flapping efficiency depend on the stiffness of a passive compliant hinge. Our dual approach of running at-scale experiments and numerical simulations gives useful guidelines for choosing wing hinge stiffnesses that lead to efficient flapping.
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Thielicke, William, i Eize J. Stamhuis. "The influence of wing morphology on the three-dimensional flow patterns of a flapping wing at bird scale". Journal of Fluid Mechanics 768 (4.03.2015): 240–60. http://dx.doi.org/10.1017/jfm.2015.71.
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The effect of airfoil design parameters, such as airfoil thickness and camber, are well understood in steady-state aerodynamics. But this knowledge cannot be readily applied to the flapping flight in insects and birds: flow visualizations and computational analyses of flapping flight have identified that in many cases, a leading-edge vortex (LEV) contributes substantially to the generation of aerodynamic force. In flapping flight, very high angles of attack and partly separated flow are common features. Therefore, it is expected that airfoil design parameters affect flapping wing aerodynamics differently. Existing studies have focused on force measurements, which do not provide sufficient insight into the dominant flow features. To analyse the influence of wing morphology in slow-speed bird flight, the time-resolved three-dimensional flow field around different flapping wing models in translational motion at a Reynolds number of $22\,000<\mathit{Re}<26\,000$ was studied. The effect of several Strouhal numbers ($0.2<\mathit{St}<0.4$), camber and thickness on the flow morphology and on the circulation was analysed. A strong LEV was found on all wing types at high $\mathit{St}$. The vortex is stronger on thin wings and enhances the total circulation. Airfoil camber decreases the strength of the LEV, but increases the total bound circulation at the same time, due to an increase of the ‘conventional’ bound circulation at the inner half of the wing. The results provide new insights into the influence of airfoil shape on the LEV and force generation at low $\mathit{Re}$. They contribute to a better understanding of the geometry of vertebrate wings, which seem to be optimized to benefit from LEVs in slow-speed flight.
Rozprawy doktorskie na temat "Scale Flapping Wings"
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Nabawy, Mostafa. "Design of insect-scale flapping wing vehicles". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/design-of-insectscale-flapping-wing-vehicles(5720b8af-a755-4c54-beb6-ba6ef1a13168).html.
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This thesis contributes to the state of the art in integrated design of insect-scale piezoelectric actuated flapping wing vehicles through the development of novel theoretical models for flapping wing aerodynamics and piezoelectric actuator dynamics, and integration of these models into a closed form design process. A comprehensive literature review of available engineered designs of miniature rotary and flapping wing vehicles is provided. A novel taxonomy based on wing and actuator kinematics is proposed as an effective means of classifying the large variation of vehicle configurations currently under development. The most successful insect-scale vehicles developed to date have used piezoelectric actuation, system resonance for motion amplification, and passive wing pitching. A novel analytical treatment is proposed to quantify induced power losses in normal hover that accounts for the effects of non uniform downwash, wake periodicity and effective flapping disc area. Two different quasi-steady aerodynamic modelling approaches are undertaken, one based on blade element analysis and one based on lifting line theory. Both approaches are explicitly linked to the underlying flow physics and, unlike a number of competing approaches, do not require empirical data. Models have been successfully validated against experimental and numerical data from the literature. These models have allowed improved insight into the role of the wing leading-edge vortex in lift augmentation and quantification of the comparative contributions of induced and profile drag for insect-like wings in hover. Theoretical aerodynamic analysis has been used to identify a theoretical solution for the optimum planform for a flapping wing in terms of chord and twist as a function of span. It is shown that an untwisted elliptical planform minimises profile power, whereas a more highly tapered design such as that found on a hummingbird minimises induced power. Aero-optimum wing kinematics for hovering are also assessed. It is shown that for efficient flight the flapping velocity should be constant whereas for maximum effectiveness the flapping velocity should be sinusoidal. For both cases, the wing pitching at stroke reversal should be as rapid as possible. A dynamic electromechanical model of piezoelectric bending actuators has been developed and validated against data obtained from experiments undertaken as part of this thesis. An expression for the electromechanical coupling factor (EMCF) is extracted from the analytical model and is used to understand the influence of actuator design variables on actuator performance. It is found that the variation in EMCF with design variables is similar for both static and dynamic operation, however for light damping the dynamic EMCF will typically be an order of magnitude greater than for static operation. Theoretical contributions to aerodynamic and electromechanical modelling are integrated into a low order design method for propulsion system sizing. The method is unique in that aside from mass fraction estimation, the underlying models are fully physics based. The transparency of the design method provides the designer with clear insight into effects of changing core design variables such as the maximum flapping amplitude, wing mass, transmission ratio, piezoelectric characteristics on the overall design solution. Whilst the wing mass is only around 10% of the actuator mass, the effective wing mass is 16 times the effective actuator mass for a typical transmission ratio of 10 and hence the wing mass dominates the inertial contribution to the system dynamics. For optimum aerodynamic effectiveness and efficiency it is important to achieve high flapping amplitudes, however this is typically limited by the maximum allowable field strength of the piezoelectric material used in the actuator.
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Whitney, John Peter. "Design and Performance of Insect-Scale Flapping-Wing Vehicles". Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10374.
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Micro-air vehicles (MAVs)—small versions of full-scale aircraft—are the product of a continued path of miniaturization which extends across many fields of engineering. Increasingly, MAVs approach the scale of small birds, and most recently, their sizes have dipped into the realm of hummingbirds and flying insects. However, these non-traditional biologically-inspired designs are without well-established design methods, and manufacturing complex devices at these tiny scales is not feasible using conventional manufacturing methods. This thesis presents a comprehensive investigation of new MAV design and manufacturing methods, as applicable to insect-scale hovering flight. New design methods combine an energy-based accounting of propulsion and aerodynamics with a one degree-of-freedom dynamic flapping model. Important results include analytical expressions for maximum flight endurance and range, and predictions for maximum feasible wing size and body mass. To meet manufacturing constraints, the use of passive wing dynamics to simplify vehicle design and control was investigated; supporting tests included the first synchronized measurements of real-time forces and three-dimensional kinematics generated by insect-scale flapping wings. These experimental methods were then expanded to study optimal wing shapes and high-efficiency flapping kinematics. To support the development of high-fidelity test devices and fully-functional flight hardware, a new class of manufacturing methods was developed, combining elements of rigid-flex printed circuit board fabrication with "pop-up book" folding mechanisms. In addition to their current and future support of insect-scale MAV development, these new manufacturing techniques are likely to prove an essential element to future advances in micro-optomechanics, micro-surgery, and many other fields.Engineering and Applied Sciences
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Chirarattananon, Pakpong. "Flight Control of a Millimeter-Scale Flapping-Wing Robot". Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:13070057.
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Flying insects display remarkable maneuverability. Unlike typical airplanes, these insects are able to execute an evasive action, rapidly change their flight speed and direction, or leisurely land on flowers buffeted by wind, exhibiting aerodynamic feats unmatched by any state-of-the-art aircraft. By subtly tuning their wing motions, they generate and manipulate unsteady aerodynamic phenomenon that is the basis of their extraordinary maneuverability.
Inspired by these tiny animals, scientists and engineers have pushed the boundaries of technology in many aspects, including meso-scale fabrication, electronics, and artificial intelligence, to develop autonomous millimeter-scale flapping-wing robots. In this thesis, we demonstrate, on real insect-scale robots, that using only an approximate model of the aerodynamics and flight dynamics in combination with conventional tools in nonlinear control, the inherently unstable flapping-wing robot can achieve steady hover. We present the development of flight controllers that gradually enhance the flight precision, allowing the robot to realize increasingly aggressive trajectories, including a highly acrobatic maneuver---perching on a vertical surface, as observed in its natural counterparts. We also demonstrate that these experiments lead to higher fidelity of in-flight aerodynamic models, strengthening our understanding of the dynamics of the robot and real insects.Engineering and Applied Sciences
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Ma, Kevin Yuan. "Mechanical design and manufacturing of an insect-scale flapping-wing robot". Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:23845433.
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Despite the prevalence of insect flight as a form of locomotion in nature, manmade aerial systems have yet to match the aerial prowess of flying insects. Within a tiny body volume, flying insects embody the capabilities to flap seemingly insubstantial wings at very high frequencies and sustain beyond their own body weight in flight. A precise authority over their wing motions enables them to respond to obstacles and threats in flight with unrivaled speed and grace.
Motivated by a desire for comparably agile flying machines, research efforts in the last decade have generated crucial developments for realizing an artificial instantiation of insect flight. The need for tiny, high-efficiency mechanical components has produced unconventional solutions for propulsion, actuation, and manufacturing. Early vehicle designs proved to be flightworthy but were critically limited by the inability to produce control torques in flight. In this thesis, we synthesize all existing technologies for insect-scale manufacturing and actuation, and we introduce a new vehicle design, the "dual actuator bee," to address the need for flight control. Our work culminates in the first demonstration of controlled, hovering flight of an insect-scale, flapping-wing robot.
As the ultimate goal for this research effort is the creation of fully autonomous flying robots, these vehicles must sustain their own power sources and intelligence. To that end, we explore the challenges of scaling flapping-wing flight to attain greater lift forces. Using a scaling heuristic to determine key vehicle specifications, we develop and successfully demonstrate a hover-capable vehicle design that possesses the requisite payload capacity for the full suite of components required for control autonomy. With this operational vehicle as a point of reference, we introduce an iterative sizing procedure for specifying a vehicle design with payload capacity capable of supporting power autonomy. In the development of these vehicles, the reliability of their construction has been a substantial challenge. We present strategies for systematically addressing issues of vehicle construction. Together, this suite of results demonstrates the feasibility of achieving artificial, insect-like flight.Engineering and Applied Sciences - Engineering Sciences
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Svanberg, Craig E. "Biomimetic micro air vehicle testing development and small scale flapping-wing analysis /". Wright-Patterson Air Force Base, Ohio : Ft. Belvior, VA : Springfield, Va. : Air Force Institute of Technology, Graduate School of Engineering and Management ; Available to the public through the Defense Technical Information Center ; National Technical Information Service [distributor], 2008. http://www.dtic.mil/dtic/.
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Thesis (M.S. in Engineering and Management)--Air Force Institute of Technology, March 2008.Title from reproduction cover. "March 2008." Thesis advisor: Dr. Mark Reeder. Performed by the Air Force Institute of Technology, Graduate School of Engineering and Management (AFIT/EN); sponsored by the Air Force Research Laboratory. Submitted in partial fulfillment of the requirements for the degree of Master of Science in Aeronautical Engineering from the Air Force Institute of Technology, March 2008.--P. [ii]. "AFIT/GAE/ENY/08-M27." Includes bibliographical references (p. 99-100). Also available online from the DTIC Online Web site.
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Teoh, Zhi Ern. "Design of Hybrid Passive and Active Mechanisms for Control of Insect-Scale Flapping-Wing Robots". Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:23845481.
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Flying insects exhibit a remarkable ability to fly in environments that are small, cluttered and highly dynamic. Inspired by these animals, scientist have made great strides in understanding the aerodynamic mechanisms behind insect-scale flapping-wing flight. By applying these mechanisms together with recent advances in meso-scale fabrication techniques, engineers built an insect-scale flapping-wing robot and demonstrated hover by actively controlling the robot about its roll and pitch axes. The robot, however, lacked control over its yaw axis preventing control over its heading angle.
In this thesis, we show that the roll and pitch axes of a single actuator insect-scale flapping-wing robot can also be passively stabilized by the addition of a pair of aerodynamic dampers. We develop design guidelines for these dampers, showing that the previously unstable robot with the addition of the dampers is able to perform stable vertical flights and altitude control. To address the lack of yaw control, we develop a yaw torque generating mechanism inspired by the fruit fly wing hinge. We present the development of this mechanism in three stages: from the conceptual stage, to the torque measurement stage and finally to a hover capable stage. We show that the robot is able to generate sufficient yaw torque enabling the robot to transition from hover to heading control maneuvers.Engineering and Applied Sciences - Engineering Sciences
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Timmerman, Kathleen M. "A Hardware Compact Genetic Algorithm for Hover Improvement in an Insect-Scale Flapping-Wing Micro Air Vehicle". Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347296530.
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Mukherjee, Sujoy. "Structural Modeling And Analysis Of Insect Scale Flapping Wing". Thesis, 2012. https://etd.iisc.ac.in/handle/2005/2021.
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Micro Air Vehicles (MAVs) are defined as a class of vehicles with their larger dimension not exceeding 15 cm and weighing 100 gm. The three main approaches for providing lift for such vehicles are through fixed, rotating and flapping wings. The flapping wing MAVs are more efficient in the low Reynolds-number regime than conventional wings and rotors. Natural flapping flyers, such as birds and insects, serve as a natural source of inspiration for the development of MAV. Flapping wing design is one of the major challenges to develop an MAV because it is not only responsible for the lift, but also propulsion and maneuvers. Two important issues are addressed in this thesis: (1) an equivalent beam-type modeling of actual insect wing is proposed based on the experimental data and (2) development of the numerical framework for design and analysis of insect scale smart flapping wing. The experimental data is used for structural modeling of the blowfly Calliphora wing as a stepped cantilever beam with nine spanwise sections of varying mass per unit lengths, flexural rigidity (EI) and torsional rigidity (GJ) values. Natural frequencies, both in bending and torsion, are obtained by solving the homogeneous part of the respective governing differential equations using the finite element method. It is found that natural frequency in bending and torsion are 3.17 and 1.57 times higher than flapping frequency of Calliphora wing, respectively. The results provide guidelines for the biomimetic structural design of insect-scale flapping wings. In addition to the structural modeling of the insect wing, development of the biomimetic mechanisms played a very important role to achieve a deeper insight of the flapping flight. Current biomimetic flapping wing mechanisms are either dynamically scaled or rely on pneumatic and motor-driven flapping actuators. Unfortunately, these mechanisms become bulky and flap at very low frequency. Moreover, mechanisms designed with conventional actuators lead to high weight and system-complexity which makes it difficult to mimic the complex wingbeat kinematics of the natural flyers. The usage of the actuator made of smart materials such as ionic polymer metal composites (IPMCs) and piezoceramics to design flapping wings is a potential alternative. IPMCs are a relatively new type of smart material that belongs to the family of Electroactive Polymers (EAP) which is also known as “artificial muscles”. In this work, structural modeling and aerodynamic analysis of a dragonfly inspired IPMC flapping wing are performed using numerical simulations. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. Later, a comparative study of the performances of three IPMC flapping wings having the same size as the actual wings of three different dragonfly species Aeshna Multicolor, Anax Parthenope Julius and Sympetrum Frequens is conducted. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. In addition to the IPMC, piezoelectric materials are also considered to design a dragonfly inspired flapping wing because they have several attractive features such as high bandwidth, high output force, compact size and high power density. The wings of birds and insects move through a large angle which may be obtained using piezofan through large deflection. Piezofan which is one of the simple motion amplifying mechanisms couples a piezoelectric unimorph to an attached flexible wing and is competent to produce large deflection especially at resonance. Non-linear dynamic model for the piezoelectrically actuated flapping wing is done using energy method. It is shown that flapping angle variations of the smart flapping wing are similar to the actual dragonfly wing for a specific feasible voltage. Subsequently, a comparative study of the performances of three piezoelectrically actuated flapping wings is performed. Numerical results show that the flapping wing based on geometry of dragonfly Sympetrum Frequens wing is suitable for low speed flight and it represents a potential candidate for use in insect scale micro air vehicles. In this study, single crystal piezoceramic is also considered for the flapping wing design because they are the potential new generation materials and have attracted considerable attention due to superior electromechanical properties. It is found that the use of single crystal piezoceramic can lead to considerable amount of wing weight reduction and increase of aerodynamic forces compared to conventional piezoelectric materials such as PZT-5H. It can also be noted that natural fliers flap their wings in a vertical plane with a change in the pitch of the wings during a flapping cycle. In order to capture this particular feature of the wingbeat kinematics, coupled flapping-twisting non-linear dynamic modeling of piezoelectrically actuated flapping wing is done using energy method. Excitation by the piezoelectric harmonic force generates only the flap bending motion, which in turn, induces the elastic twist motion due to interaction between flexural and torsional vibrations modes. It is found that the value of average lift reaches to its maximum when the smart flapping wing is excited at a frequency closer to the natural frequency in torsion. Moreover, consideration of the elastic twisting of flapping wing leads to an increase in the lift force.
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Mukherjee, Sujoy. "Structural Modeling And Analysis Of Insect Scale Flapping Wing". Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2021.
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Micro Air Vehicles (MAVs) are defined as a class of vehicles with their larger dimension not exceeding 15 cm and weighing 100 gm. The three main approaches for providing lift for such vehicles are through fixed, rotating and flapping wings. The flapping wing MAVs are more efficient in the low Reynolds-number regime than conventional wings and rotors. Natural flapping flyers, such as birds and insects, serve as a natural source of inspiration for the development of MAV. Flapping wing design is one of the major challenges to develop an MAV because it is not only responsible for the lift, but also propulsion and maneuvers. Two important issues are addressed in this thesis: (1) an equivalent beam-type modeling of actual insect wing is proposed based on the experimental data and (2) development of the numerical framework for design and analysis of insect scale smart flapping wing. The experimental data is used for structural modeling of the blowfly Calliphora wing as a stepped cantilever beam with nine spanwise sections of varying mass per unit lengths, flexural rigidity (EI) and torsional rigidity (GJ) values. Natural frequencies, both in bending and torsion, are obtained by solving the homogeneous part of the respective governing differential equations using the finite element method. It is found that natural frequency in bending and torsion are 3.17 and 1.57 times higher than flapping frequency of Calliphora wing, respectively. The results provide guidelines for the biomimetic structural design of insect-scale flapping wings. In addition to the structural modeling of the insect wing, development of the biomimetic mechanisms played a very important role to achieve a deeper insight of the flapping flight. Current biomimetic flapping wing mechanisms are either dynamically scaled or rely on pneumatic and motor-driven flapping actuators. Unfortunately, these mechanisms become bulky and flap at very low frequency. Moreover, mechanisms designed with conventional actuators lead to high weight and system-complexity which makes it difficult to mimic the complex wingbeat kinematics of the natural flyers. The usage of the actuator made of smart materials such as ionic polymer metal composites (IPMCs) and piezoceramics to design flapping wings is a potential alternative. IPMCs are a relatively new type of smart material that belongs to the family of Electroactive Polymers (EAP) which is also known as “artificial muscles”. In this work, structural modeling and aerodynamic analysis of a dragonfly inspired IPMC flapping wing are performed using numerical simulations. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. Later, a comparative study of the performances of three IPMC flapping wings having the same size as the actual wings of three different dragonfly species Aeshna Multicolor, Anax Parthenope Julius and Sympetrum Frequens is conducted. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. In addition to the IPMC, piezoelectric materials are also considered to design a dragonfly inspired flapping wing because they have several attractive features such as high bandwidth, high output force, compact size and high power density. The wings of birds and insects move through a large angle which may be obtained using piezofan through large deflection. Piezofan which is one of the simple motion amplifying mechanisms couples a piezoelectric unimorph to an attached flexible wing and is competent to produce large deflection especially at resonance. Non-linear dynamic model for the piezoelectrically actuated flapping wing is done using energy method. It is shown that flapping angle variations of the smart flapping wing are similar to the actual dragonfly wing for a specific feasible voltage. Subsequently, a comparative study of the performances of three piezoelectrically actuated flapping wings is performed. Numerical results show that the flapping wing based on geometry of dragonfly Sympetrum Frequens wing is suitable for low speed flight and it represents a potential candidate for use in insect scale micro air vehicles. In this study, single crystal piezoceramic is also considered for the flapping wing design because they are the potential new generation materials and have attracted considerable attention due to superior electromechanical properties. It is found that the use of single crystal piezoceramic can lead to considerable amount of wing weight reduction and increase of aerodynamic forces compared to conventional piezoelectric materials such as PZT-5H. It can also be noted that natural fliers flap their wings in a vertical plane with a change in the pitch of the wings during a flapping cycle. In order to capture this particular feature of the wingbeat kinematics, coupled flapping-twisting non-linear dynamic modeling of piezoelectrically actuated flapping wing is done using energy method. Excitation by the piezoelectric harmonic force generates only the flap bending motion, which in turn, induces the elastic twist motion due to interaction between flexural and torsional vibrations modes. It is found that the value of average lift reaches to its maximum when the smart flapping wing is excited at a frequency closer to the natural frequency in torsion. Moreover, consideration of the elastic twisting of flapping wing leads to an increase in the lift force.
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Swarrup, J. Sakthi. "Ionic Polymer Metal Composite Actuators for Insect Scale Flapping Wing Micro Air Vehicle". Thesis, 2015. https://etd.iisc.ac.in/handle/2005/4812.
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Flapping wing micro air vehicles (MAV) have broad applications such as exploration
in hazardous environment, reconnaissance, search and rescue. Ionic polymer metal
composites (IPMC) have emerged as a promising material in actuators and sensors
for use in flapping wing of MAVs. Though IPMC satifis es most of the criteria needed
for bio-inspired design, achieving high stiffness, actuation force, frequency and
flapping angle remains a challenge. The main objective of this thesis is to study the
various factors which influence the actuation performance of IPMC by mathematical
modelling, optimize design parameters for fabrication of high performing IPMC,
design an actuator-sensor array of IPMCs and fabrication of hybrid IPMC-polymer
structure as dragon y scale flapping wing of micro air vehicles. The dynamic mathematical
modelling of IPMC is carried out by variational principle using the Buechler
and Leo model and the performance of model actuators is studied. The structural
modelling of nanocomposite-based IPMC has been carried out to study the e ect of
inherent properties of the materials used in IPMC fabrication. The studies reveal that
the nanocomposite-based IPMC, IPMNC-RuO2/Na on and IPMNC-LbL CNC having
low thickness and high Youngs modulus can be actuated for higher deflection at
typical flapping frequencies (40-47 Hz). The structural modelling of unencapsulated
IPMCs (u-IPMC) intended for use under dry and humid environment is carried out for
optimization of design parameters for retention of water and to study the influence of
water activity on the actuation. IPMC designed with Na on having equivalent weight
900-1100, preheated at 30 C and sodium cation is more promising for optimum retention
of water and actuation. For operation in these environments, the actuation
parameters can be tuned to the desirable level by changing the water activity and
temperature of the user environment. For the design of dragon
y size flapping wing, the flexural stiffness of IPMC should be comparable to that of the actual insect wing
for proper flapping motion at higher flapping angle and deflection. Therefore, structural
modelling of dragon y scale IPMC is carried out. The IPMC actuator [IPMNCRuO
2/Na on with thickness 450 m (Na on 400 m and both electrodes 50 m ),
resonant frequency 31.5 Hz, Youngs modulus 2 GPa, mass 378 mg] modelled in
dragon y species, Sympetrum Frequens, shows better flapping and actuation than the
other insect scale actuators. In structural design of insect scale flapping wing, the
attachment of wing on the IPMC actuator as an array of actuator-sensor may lead
to self-powered flapping. The influence of attachment of wing on the actuator on the
actuation force and frequency to lift and flap the attached wing is studied. High frequency
(20 Hz) actuator (170 mg semi wet) with an attached mass equivalent to the
wing mass, produced higher actuation force, with reasonable frequency and deflection.
The studies on the dragon y scale flapping wing fabricated with IPMC-cyclic ole n
copolymer (COC) membrane based hybrid structure and the performance of various
wing confi gurations reveal that high frequency IPMC actuator fi tted with the high
modulus COC membrane with two-vein confi guration (leading edge and centre of the
wing) is the more promising structure as dragon y scale flapping wing. In conclusion,
with the analysis and design presented in this thesis, the optimized design and material
parameters of IPMC can be exploited for increased actuation performance at
the dragon y (Sympetrum Frequens) insect size. The high frequency IPMC can act
as flapping wing with capabilities of a sensor. The hybrid structure comprising high
frequency IPMC actuator fitted with the high modulus COC polymer membrane is a
promising flapping wing. The output voltage of IPMC wing could indicate the level of
actuation performance of the wing at different conditions such as change in temperature,
humidity or water content. Moreover, the actuator-sensor array can also help to
predict the environmental conditions and also used as an input for control algorithms.
Książki na temat "Scale Flapping Wings"
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Hahne, David E. Full-scale semispan tests of a business-jet wing with a natural laminar flow airfoil. Hampton, Va: Langley Research Center, 1991.
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Skarsgard, Andrew Jonathan. The implementation of flapping-wing propulsion for a full-scale ornithopter. [Downsview, Ont.]: Department of Aerospace Science and Engineering, University of Toronto, 1991.
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Skarsgard, Andrew Jonathan. The implementation of flapping-wing propulsion for a full-scale ornithopter. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1992.
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Fowler, Stuart Jardim. The design and development of a wing for a full-scale piloted engine-powered flapping-wing aircraft (Ornithopter). Ottawa: National Library of Canada, 1995.
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Full-scale semispan tests of a business-jet wing with a natural laminar flow airfoil. [Washington, D.C.]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1991.
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Full-scale semispan tests of a business-jet wing with a natural laminar flow airfoil. [Washington, D.C.]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1991.
Znajdź pełny tekst źródłaCzęści książek na temat "Scale Flapping Wings"
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Yao, Jie, i K. S. Yeo. "The Effect of Wing Mass and Wing Elevation Motion During Insect Forward Flight". W Supercomputing Frontiers, 31–42. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-10419-0_3.
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AbstractThis paper is concerned with the numerical simulation of the forward flight of a high Reynolds number flapping-wing flyer, modelled after the hummingbird hawkmoth (Macroglossum stellatarum). The numerical model integrated a Navier-Stokes solver with the Newtonian free-body dynamics of the model insect. The primary cyclic kinematics of wings were assumed to be sinusoidal for simplicity here, which comprises sweeping, elevating and twisting related wing actions. The free flight simulation is very computationally intensive due to the large mesh scale and the iterative solution for the FSI problem, so parallelization is essential in the numerical simulation. Two parallelization techniques are used in current simulation, i.e., open multi-processing (OpenMP) and graphics processing units (GPU) acceleration. The forward flight mainly consists of two stages, i.e., the body pitching down from the normal hovering posture and the following forward acceleration. During this process, the effect of the wing mass and the wing elevation motion is very important, which is investigated in detail. It is found that Oval-shaped wing elevating motion can help to generate large pitching down moment so that the flyer can quickly adjust its orientation for forward acceleration. Moreover, wing mass tends to magnify the effect and prohibits the growth of pitching down velocity, which is favourable aspect. The present study provides detailed information of the coupled dynamics of fluid and flyer in free flight condition, as well as offers a prospective approach that could complement existing experiments in a wider study of insect flight and maneuver.
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Moses, Kenneth C., Nathaniel I. Michaels, Joel Hauerwas, Mark Willis i Roger D. Quinn. "An Insect-Scale Bioinspired Flapping-Wing-Mechanism for Micro Aerial Vehicle Development". W Biomimetic and Biohybrid Systems, 589–94. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-63537-8_54.
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Lovejoy, Shaun. "Macroweather predictions and climate projections". W Weather, Macroweather, and the Climate. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190864217.003.0011.
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“Does the Flapping of a Butterfly’s Wings in Brazil Set off a Tornado in Texas?” This was the provocative title of an address given by Edward Lorenz, the origin for the (nearly) household expression “butterfly effect.” It was December 1972 and it had been nearly ten years since he had discovered it,1 yet its significance was only then being recognized. Lorenz explained: “In more technical language, is the behavior of the atmosphere unstable to small perturbations?” His answer: “Although we cannot claim to have proven that the atmosphere is unstable, the evidence that it is so is overwhelming.” Imagine two planets identical in every way except that on one there is a butterfly that flaps its wings. The butterfly effect means that their future evolutions are “sensitively dependent” on the initial conditions, so that a mere flap of a wing could perturb the atmosphere sufficiently so that, eventually, the weather patterns on the two planets would evolve quite differently. On the planet with the Brazilian butterfly, the number of tornadoes would likely be the same. But on a given day, one might occur in Texas rather than Oklahoma. This sensitive dependence on small perturbations thus limits our ability to predict the weather. For Earth, Lorenz estimated this predictability limit to be about two weeks. From Chapters 4 and 5 and the discussion that follows, we now understand it as the slightly shorter weather– macroweather transition scale. In Chapter 1, we learned that the ratio of the nonlinear to linear terms in the (deterministic) equations governing the atmosphere is typically about a thousand billion. The nonlinear terms are the mathematical expressions of physical mechanisms that can blow up microscopic perturbations into large effects. Therefore, we expect instability. Chapter 4, we examined instability from the point of view of the higher level statistical laws— the fact that, at weather scales, the fluctuation exponents H for all atmospheric fields are positive (in space, up to the size of the planet; in time, up to the weather– macroweather transition scale at five to ten days).
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Grondel, Sébastien, Mathieu Colin, Marie Zwingelstein-Colin, Sofiane Ghenna, Caroline Soyer, Eric Cattan i Olivier Thomas. "Towards the Use of Flapping Wing Nano Aerial Vehicles". W Modern Technologies Enabling Safe and Secure UAV Operation in Urban Airspace. IOS Press, 2021. http://dx.doi.org/10.3233/nicsp210006.
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In the last decade, the potential of Micro Aerial Vehicles (MAVs) has generated an enormous interest in this technology and numerous applications have therefore been proposed in military and civilian fields. More recently, researchers have begun to work on a new and miniaturized generation called Flapping Wing Nano Aerial Vehicles (FWNAVs) who could be particularly promising for the indoor inspection. Before to be able to use efficiently these FWNAVs, there are however significant scientific and technical challenges to solve due to the scaling down. These include aerodynamics of low Reynolds number flow, small-scale power generation and power storage, navigation and communication, propulsion and control as well as manufacturability. This paper sets out the potential applications of such FWNAVs and reviews some of the challenges related to aerodynamics, stability, and design trends.
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Altenbuchner, Cornelia, i James E. Hubbard. "Flexible Multi-Body Dynamics Modeling Methodology Implementation Avian Scale Flapping Wing Flyer". W Modern Flexible Multi-Body Dynamics Modeling Methodology for Flapping Wing Vehicles, 73–107. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-814136-6.00004-4.
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Altenbuchner, Cornelia, i James E. Hubbard. "Aerodynamics Modeling for Flexible Multi-Body Dynamics Modeling Methodology Implementation Avian Scale Flapping Wing Flyer". W Modern Flexible Multi-Body Dynamics Modeling Methodology for Flapping Wing Vehicles, 109–27. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-814136-6.00005-6.
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Altenbuchner, Cornelia, i James E. Hubbard. "Concluding Remarks About Modern Modeling Methodology Implementation and Flight Physics of Avian Scale Flight Robotics Systems". W Modern Flexible Multi-Body Dynamics Modeling Methodology for Flapping Wing Vehicles, 155–61. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-814136-6.00007-x.
Pełny tekst źródłaStreszczenia konferencji na temat "Scale Flapping Wings"
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Jankauski, Mark A. "Low-Order Aeroelastic Modeling of Flapping, Flexible Wings". W ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85150.
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Flapping insect wings deform under aerodynamic and inertial-elastic loads. Existing aeroelastic wing models are computationally expensive, and consequently, the physics governing flexible wing deformation are not well understood. This paper develops a low-order, one-way coupled aeroelastic model of an arbitrary geometry wing undergoing three-dimensional rotation. The model is developed using the Lagrangian formulation and generalized aerodynamic loads are determined through a blade-element-momentum approach. The in-air and in-vacuum responses of a simulated Hawkmoth wing are compared for various conditions. During normal flight, simulation results show aerodynamic loading causes a 25% increase in maximum wingtip deflection versus a wing flapping in vacuum. This suggests aerodynamics plays a moderate role in structural deformation. Further parametric studies indicate (1) deviations in flap frequency excite torsional resonance and (2) the relative phase between pitch and roll rotations dramatically affects in-air wing response. Both the aeroelastic model and simulation results can guide optimal wing design for small-scale flapping wing micro air vehicles.
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Han, Jong-Seob, Jong-Wan Lee i Jae-Hung Han. "Towing Tank Experiments for Flapping-Wing Aerodynamics". W ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69566.
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This paper presents an empirical approach for flapping-wing aerodynamics using a servo-driven towing tank and a dynamically scale-up robotic manipulator. Time-varying aerodynamic force and moment were measured, and digital particle image velocimetry in multiple cross-sections were conducted. Three case studies showed that the towing tank experiment could be an effective way to investigate the aerodynamic characteristics in detail, which are difficult to be predicted by other conventional approaches. The force and moment measurements clarified that an advance ratio has significant role in governing the LEV behavior and consequent aerodynamic performance of flapping wings. Results for moving sideways showed the effects of the wing-wing and wing-body interaction, and the usefulness of the towing tank experiments for analyzing the flight dynamic characteristics. It was also shown that the towing tank experiments can be applicable to realistic wing motions; test results using the wing kinematics of a living insect in forward flight were well compatible with the trim condition of the insect.
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Zdunich, Patrick. "Separated Flow Discrete Vortex Model for Nano-Scale Hovering Flapping Wings". W 26th AIAA Applied Aerodynamics Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2008. http://dx.doi.org/10.2514/6.2008-6245.
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Yin, Bo, i Guowei Yang. "Investigation of Obstacle Effects on the Aerodynamic Performance of Flapping Wings". W ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69264.
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The study of highly unsteady wing flapping includes the large scale vortices, complicated locomotion/dynamics and deformable wing structures. When flapping insects/birds approach or perch on some objects, such as ground, wall or obstacle, the solid boundary dissipates, absorbs and bounces the leading edge, trailing edge and wing tip vortices, which are generated and shed during the flapping flight. Such phenomenon creates a high pressure area, leads to cushion effect and influences the aerodynamics, stability and maneuverability significantly. This paper uses immersed boundary method (IBM) to numerically study the aerodynamic performance of flapping wing in proximity of obstacles, investigate the distance, flapping motion and wing flexibility effects and relevant symmetric/asymmetric flow patterns, research the influence of vortex generating and shedding to the lift/drag change, explore the key distance and reveal the mechanism how insects/birds adjust the flapping motion to achieve ideal flight. Such research could theoretically support the development of micro-bionic flapping wing vehicle.
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Fuchiwaki, Masaki, Taichi Kuroki, Kazuhiro Tanaka i Takahide Tabata. "Vortex Structure of a Vortex Ring Over a Butterfly Wing and its Dynamic Behavior". W ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-19010.
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Micro-Air-Vehicles (MAVs) that mimic the flight mechanisms of insects have been attracting significant attention in recent years. These technologies are developed with the aim of lifesavings in the area with the risk of secondary disasters, maintenance works for constructions such as bridges, information collection on planet searches, monitoring of security risks for the purpose of security means. A number of researchers have attempted to develop small flap flying objects and MAV with various actuators and devices. However, these robots were not practical. One of the reasons for this is that the flying mechanism of insects has not yet been clarified sufficiently. We have clarified that a couple of large-scale vortex is formed over the wing. The purpose of the present study is to clarify the dynamic behavior and the detailed structure of the vortices of the flapping butterfly wing, and we carried out the PIV measurement around the flapping butterfly wing. The vortex ring develops over the wings when the wings flap downward to the bottom dead position and then passes through the butterfly completely and grows until reaching the wake at the bottom dead position. The vortex ring develops over the wing while growing from the leading edge toward the trailing edge. The maximum vorticity of the vortex ring over the wing moves from the leading edge to the trailing edge with the downward flapping. On the other hand, the vorticity of the LEV decays with downward flapping.
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Cox, Adam, Daniel J. Monopoli, Michael Goldfarb i Ephrahim Garcia. "Development of Piezoelectrically Actuated Elastodynamic Flapping Micro-Aerial Vehicles". W ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0552.
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Abstract A discussion of the principles involved in small-scale flight is presented here. In addition, several novel mechanisms have been developed in an attempt to mechanically emulate flapping flight on the meso-scale. Wings are being developed which will exploit particular material properties to emulate the dynamic characteristics of insect wings. The flapping mechanisms developed in this paper use piezoelectric unimorph actuators integrated with compliant, solid-state flexure based mechanisms. Four and five bar linkages are used to convert the linear unimorph output into a single degree-of-freedom rotational flapping motion. Due to their capacitive nature, piezoelectric actuators generally dissipate less power than traditional actuation methods such as electromagnetic motors. Piezoelectric actuators possess a high power density and are capable of high force output. They are frequently used to induce structural resonances, making them suitable for use in these devices. The dynamics of these systems rely on the mechanics of flexure mechanisms, the mechanical and electrical behavior of the piezoelectric elements, and the aerodynamic interaction of the wings and the air, resulting in a complex, nonlinear problem.
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Sridhar, Madhu, i Chang-Kwon Kang. "Aerodynamic Performance of Flexible Flapping Wings at Bumblebee Scale in Hover Flight". W 53rd AIAA Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2015. http://dx.doi.org/10.2514/6.2015-0254.
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Matta, Alexander, i Javid Bayandor. "An Analytical Study on the Effect of Active Wing Folding and Twist on the Aerodynamic Performance and Energy Consumption of a Bio-Inspired Ornithopter". W ASME 2016 Fluids Engineering Division Summer Meeting collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fedsm2016-7741.
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The vast majority of bird scale ornithopters still utilize single active degree of freedom wings in which the flapping motion is actuated at the root of the wing. Yet, as we look to nature, we see that birds utilize more than one active degree of freedom. The purpose of this study is to determine the effect of dynamic wing twist and wing folding on lift and thrust produced by a flapping wing as well as their effects on power consumption. The method of analysis this study utilizes is a version of MST, a Modified Strip Theory, in order to model the aerodynamics of the wing. Both non-folding and folding wing scenarios are considered where the parameters varied include dynamic wing twist amplitude, time averaged wing twist, and dynamic wing twist and flapping phase offset. Furthermore, unlike many other theoretical studies, when examining power consumption both the aerodynamic force as well as inertial effects are considered as inertial effects can be of the same order as aerodynamic force. Moreover, the negative power occurring on the upstroke cannot be always considered to lead to energy transfer back into the system as many studies assume. Thus, this study discusse the impact of negative power and its implications on ornithopter design.
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Mateti, Kiron, Zheqian Zhang, Srinivas A. Tadigadapa i Christopher D. Rahn. "Thrust Modeling and Measurement for Clapping Wing Nano Air Vehicles Actuated by Piezoelectric T-Beams". W ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3664.
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Insects that use a Weis-Fogh clap and fling mechanism, where their wings clap together and fling apart, show an increase in thrust per unit muscle mass compared to conventional flapping insects. This has motivated the development of macroscale clapping winged ornithopters with four wings. Most clapping wing ornithopters use electric motors with gears and linkages that are inefficient at the sub-millimeter (meso)scale. Piezoelectric actuators are attractive for Nano Air Vehicles (NAVs) because they have high power density, high efficiency, and new fabrication processes have been developed at this scale. Recently developed piezoelectric T-beam actuators are monolithically fabricated from bulk PZT and function like unimorph actuators without the need to bond passive layers. These bending actuators drive a novel four-winged clapping NAV that produces thrust. This paper studies thrust force generation of a clapping wing NAV using a model-based approach. A three degree of freedom dynamic model of the clapping wing nano air vehicle is derived including unsteady aerodynamic forces and torques. The model is validated using experimental data from a NAV prototype.
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Ishimoto, Sagiri, i Hiromu Hashimoto. "Self-Excited Vibration Model of Dragonfly’s Wing Based on the Concept of Bionic Design for Small- or Micro-Sized Actuators". W ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/vib-4185.
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Abstract This paper describes a self-excited vibration model of dragonfly’s wing based on the concept of bionic design, which is expected as a technological hint to solve the scale effect problems in developing the small- or micro-sized actuators. From a morphological consideration of flight muscle of dragonfly, the nonlinear equation of motion for the wing considering the air drag force due to flapping of wing is formulated. In the model, the dry friction-type and Van der Pol-type driving forces are employed to power the flight muscles and to generate the stable self-excited wing vibration. Two typical Japanese dragonflies, “Anotogaster sieboldii Selys” and “Sympetrum frequens Selys”, are selected as examples, and the self-excited vibration analyses for these dragonfly’s wings are demonstrated. The linearized solutions for the nonlinear equation of motion are compared with the nonlinear solutions, and the vibration system parameters to generate the stable limit cycle of self-excited wing vibration are determined.
Raporty organizacyjne na temat "Scale Flapping Wings"
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Kroninger, Christopher, Jeffrey Pulskamp, Jessica Bronson, Ronald G. Polcawich i Eric Wetzel. Bio-Mimetic Millimeter-Scale Flapping Wings for Micro Air Vehicles. Fort Belvoir, VA: Defense Technical Information Center, marzec 2009. http://dx.doi.org/10.21236/ada496241.
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Kroninger, Christopher, Jeffrey Pulskamp, Ronald G. Polcawich i Eric Wetzel. Bio-mimetic Millimeter-scale Flapping Wings for Micro Air Vehicles, Year II. Fort Belvoir, VA: Defense Technical Information Center, kwiecień 2010. http://dx.doi.org/10.21236/ada522227.
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Riddick, Jaret C., i Asha Hall. Three-Dimensional Bending Analysis of Functionally-Modified Bimorph PZT Actuator for cm-Scale Flapping Wing. Fort Belvoir, VA: Defense Technical Information Center, lipiec 2011. http://dx.doi.org/10.21236/ada546404.
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