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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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Abdul, Hamid Mohd Faisal. "Aerodynamic models for insect flight". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/aerodynamic-models-for-insect-flight(057be27b-265a-45a0-b8d0-dc3c02a62a77).html.
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Numerical models of insect flapping flight have previously been developed and used to simulate the performance of insect flight. These models were commonly developed via Blade Element Theory, offering efficient computation, thus allowing them to be coupled with optimisation procedures for predicting optimal flight. However, the models have only been used for simulating hover flight, and often neglect the presence of the induced flow effect. Although some models account for the induced flow effect, the rapid changes of this effect on each local wing element have not been modelled. Crucially, this effect appears in both axial and radial directions, which influences the direction and magnitude of the incoming air, and hence the resulting aerodynamic forces. This thesis describes the development of flapping wing models aimed at advancing theoretical tools for simulating the optimum performance of insect flight. Two models are presented: single and tandem wing configurations for hawk moth and dragonfly, respectively. These models are designed by integrating a numerical design procedure to account for the induced flow effects. This approach facilitates the determination of the instantaneous relative velocity at any given spanwise location on the wing, following the changes of the axial and radial induced flow effects on the wing. For the dragonfly, both wings are coupled to account for the interaction of the flow, particularly the fact that the hindwing operates in the slipstream of the forewing. A heuristic optimisation procedure (particle swarming) is used to optimise the stroke or the wing kinematics at all flight conditions (hover, level, and accelerating flight). The cost function is the propulsive efficiency coupled with constraints for flight stability. The vector of the kinematic variables consists of up to 28 independent parameters (14 per wing for a dragonfly), each with a constrained range derived from the maximum available power, the flight muscle ratio, and the kinematics of real insects; this will prevent physically-unrealistic solutions of the wing motion. The model developed in this thesis accounts for the induced flow, and eliminates the dependency on the empirical translation lift coefficient. Validations are shown with numerical simulations for the hover case, and with experimental results for the forward flight case. From the results obtained, the effect of the induced velocity is found to be greatest in the middle of the stroke. The use of an optimisation process is shown to greatly improve the flapping kinematics, resulting in low power consumption in all flight conditions. In addition, a study on dragonfly flight has shown that the maximum acceleration is dependent on the size of the flight muscle.
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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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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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Phillips, N. "Experimental unsteady aerodynamics relevant to insect-inspired flapping-wing micro air vehicles". Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/5824.
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Small hand-held micro air vehicles (MAVs) can serve many functions unsuitable for a manned vehicle, and can be inexpensive and easily deployed. MAVs for indoor applications are underdeveloped due to their demanding requirements. Indoor requirements are best met by a flapping-wing micro air vehicle (FMAV) based on insect-like flapping-wing flight, which offers abilities of sustained hover, aerial agility, and energy efficiency. FMAV development is hampered by a lack of understanding of insect-like flapping-wing aerodynamics, particularly at the FMAV scale. An experimental programme at the FMAV scale (Reynolds number on the order of 104) was undertaken, investigating: leading-edge vortex (LEV) stability, flapping kinematic effects on lift and the flowfield, and wing planform shape effects on the flowfield. For these experiments, an apparatus employing a novel flapping mechanism was developed, which achieved variable three-degreeof- freedom insect-like wing motions (flapping kinematics) with a high degree of repeatability in air up to a 20Hz flapping frequency. Mean lift measurements and spatially dense volumetric flowfield measurements using stereoscopic particle image velocimetry (PIV) were performed while various flapping kinematic parameters and wing planform were altered, to observe their effects. Three-dimensional vortex axis trajectories were reconstructed, revealing vortex characteristics such as axial velocity and vorticity, and flow evolution patterns. The first key result was the observation of a stable LEV at the FMAV scale which contributed to half of the mean lift. The LEV exhibited vortex breakdown, but still augmented lift as Reynolds number was increased indicating that FMAVs can exploit this lifting mechanism. The second key result was the identification of the trends of mean lift versus the tested kinematic parameters at the FMAV scale, and appropriate values for FMAV design. Appropriate values for lift generation, while taking mechanical practicalities into account, included a flat wingtip trajectory with zero plunge amplitude, angle of attack at mid-stroke of 45 degrees , rotation phase of +5:5%, and maximum flapping frequency and stroke amplitude.
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Conn, Andrew T. "Development of novel flapping mechanism technologies for insect-inspired micro air vehicles". Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492441.
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Insect-inspired micro air vehicles (MAVs) have the capacity for higher lift forces and greater manoeuvrability at low flight speeds compared to conventional flight platforms, making them suitable for novel indoor flight applications. This thesis presents development studies of an actuated flapping mechanism for an insect-inspired MAV. An original theoretical understanding has shown that the kinematical constraint of a flapping mechanism fundamentally determines its complexity and performance. An under-constrained mechanism is optimal but almost always requires a linear input. A power optimisation study has demonstrated that the only technologically mature actuation devices with viable power densities for flight are rotary. Consequently, previous airborne flapping MAVs utilised constrained rotary-input mechanisms which require conventional control surfaces that significantly reduce flight manoeuvrability.
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Wilkins, P. C. "Some unsteady aerodynamics relevant to insect-inspired flapping-wing micro air vehicles". Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/2913.
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Flapping-wing micro air vehicles, based on insect-like apping, could potentially
ll a niche in the current market by o ering the ability to gather information from
within buildings. The aerodynamics of insect-like apping are dominated by a
large, lift-enhancing leading-edge vortex (LEV). Historically, the cause and structure
of this vortex have been the subject of controversy. This thesis is primarily
intended to provide insight into the LEV, using computational uid dynamics coupled
with validating experiments. The problem is simpli ed by breaking down the
complex kinematics involved in insect-like apping and examining only a part of
these kinematics; rstly in 2D, before progressing to 3D sweeping wing motions.
The thesis includes discussion of published literature in the eld, highlighting gaps
and inconsistencies in the current knowledge. Among the contributions of this thesis
are: descriptions of the e ects of changing Reynolds number and angle of attack
for 2D and 3D ows; clari cation of terminology and phenomenology, particular in
the context of 2D ows; and detailed descriptions of the development and structure
of the LEV in both 2D and 3D cases, including discussion of Kelvin-Helmholtz instability.
The issues of Strouhal number, delayed leading-edge separation, dynamic
stall and the Wagner e ect are also considered. Generally, the LEV is shown to
be unstable in 2D cases. However, in 3D cases the LEV is seen to be stable, even
if Reynolds number is increased. The stability of the LEV is found to be critically dependent on wing aspect ratio.
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Gami, A. "Experimental and computational analysis for insect inspired flapping wing micro air vehicles". Thesis, City, University of London, 2016. http://openaccess.city.ac.uk/17454/.
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Many creatures in nature have evolved the ability to fly and some seem to do so effortlessly with captivating movement. The flight characteristics of these natural fliers have greatly fascinated biologists and engineers for a long time that to this day researchers continue to actively work in this field of science with the aim of one day developing a Flapping Wing Micro Aerial Vehicle (FWMAV) which can replicate the flight of nature's creatures. These types of autonomous robotic vehicles can fulfil tasks which are not suitable for manned vehicles especially when risks to human safety are present. Flight techniques such as control, stability and manoeuvrability are flight characteristics which an FWMAV must possess if such a device is employed for various rescue missions. With this in mind symmetrical and asymmetrical wing motions are studied experimentally in the current research programme in such a way that the methodology employed for this type of flight can be implemented into future FWMAVs. In summary, the research performed during the course of this project produced innovative results in the form of the creation of two micro air vehicles with a thorough explanation of the development process and examination under experimental tests. Various parameters were analysed during the experimental tests such as force, moment, power and wing position measurements. The tests were performed on both models, one of which has the functionality to perform asymmetrical flapping and successfully generate moments about two different axes. A unique wing motion which favoured the upward vertical force production was investigated under various scenarios. The wings keep a fixed angle of attack during the downwards flapping motion and are allowed to passively rotate during the upstroke motion. Computational simulations were performed to investigate the hovering fluid dynamics, forces, moments and power required for various chordwise rotational positions and durations of wing rotation. This investigation aided in understanding the full effects of altering these parameters under hovering conditions for a rectangular wing. The valuable results found from this research program provide a better insight into various topics involving micro air vehicles in addition to developing future flight worthy insect inspired vehicles.
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Pedersen, C. B. "An indicial-polhamus model of aerodynamics of insect-like flapping wings in hover". Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/6456.
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As part of the ongoing development of Flapping-Wing Micro Air Vehicle (FMAV)
prototypes at RMCS Shrivenham,a model of insect-like wing aerodynamics in hover has been developed, and implemented as MATLAB code.The model is intended to give better insight into the various aerodynamic effects on the wing, so is as close to purely
analytical as possible. The model is modular, with the various effects treated separately.This modularity aids analysis and insight, and will allow future refinement of individual parts. However,it comes at the expense of considerable simplification,which requires empirical verification. The model starts from quasi-steady inviscid flow around a thin 2D rigid flat wing section,accounting for viscosity with the Kutta-Joukowski condition,and the leading edge suction analogy of Polhamus. Wake effects are modelled using the models of Kussner and Wagner on a prescribed wake shape,as initially used by Loewy. The model has been validated against experimental data of Dickinson's Robofly, and found to give acceptable accuracy.Some empirically inspired refinements of the Polhamus effect are outlined, but need further empirical validation.
This thesis comprises of six main parts: Part I is introductory material, and definitions, including an overview of what insect-like Rapping flight actually entails, and detailed definitions of the variables and terms used later. Part 2 describes the new theoretical model, and a simple scaling analysis of the forces and moments predicted. Part 3 deals with the MATLAB implementation of the above theory, and the considerations re-quired when adapting the theory for computational use. Part4 shows and discusses the results of the above code, against experimental measurements on Dickinson's Robofly. Part 5 is the conclusions, including a comprehensive list of all assumptions made in the theory. Part6 , the appendices, contain useful mathematical identities,and a copy of the code that was developed.
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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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Lundberg, Marcus. "Aerodynamics of Insect Flight : Effects of wind gusts on a rigid flapping NACA 0012 airfoil at Re = 3000". Thesis, KTH, Mekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-167123.
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Insects and small flyers operate at Reynolds numbers ranging from approximately 10-105 , where viscous forces are important. Due to their small size and weight, they are sensitive to small changes in the free stream during flight, such as wind gusts. First, the aerodynamics of flapping flight is briey explained. Then the lift, drag and power usage for a flapping NACA 0012 airfoil is simulated in ANSYS Fluent for different oncoming wind directions. The aim of the report is to understand how the pitching amplitude, the apping frequency and the plunging amplitude can be adjusted to compensate for oncoming wind gusts. The simulation is modelled as quasistatic since the time scale of the flapping wings of the insect is much shorter than the time scale of the wind gusts.Insekter och andra små flygande djur flyger vid låga Reynolds tal som sträcker sig från cirka 10-100 000. Det medför att viskösa krafter är viktiga. På grund av sin ringa storlek och vikt är de känsliga för små förändringar i den friströmmen under flygningen, till exempel vindbyar. Först förklaras teorin bakom aerodynamiken vid flaxande flygning. Sedan simuleras lyftkraft, dragkraft och effektförbrukning för en flaxande NACA 0012 vingprofil vid olika riktningar på friströmmen med hjälp av ANSYS Fluent. Syftet med rapporten är att förstå hur pitching-amplitud, vingslagsfrekvens och vingslagsamplitud kan justeras för att kompensera för inkommande vindbyar. Simuleringen modelleras som kvasistatisk eftersom tidsskalan hos insekters flaxande vingar normalt är mycket kortare än tidsskalan hos vindbyar.
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Ansari, Salman Ahmad. "A nonlinear, unsteady aerodynamic model for insect-like flapping wings in the hover with micro air vehicle applications". Thesis, Cranfield University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441548.
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Feaster, Jeffrey Oden. "Discovering the Complex Aerodynamics of Flapping Flight with Bio-kinematics Using Boltzmann and Eulerian Methods". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/93962.
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The cross-sectional geometry of an insect wing has historically been simplified to a rectangular, elliptic, or having a streamlined airfoil shape. Up until this point, no analysis has utilized a morphologically accurate insect wing. As such, there remains significant questions as to whether or not there are aerodynamic benefits to the wing vein structure accompanying the already known structural improvements. The present study uses a bumblebee specimen (Bombus pensylvanicus) acquired by the author, scanned using a skyscan microCT scanner, and post-processed for computational analysis. The resulting geometry captures the naturally occurring vein structures present in the bee wing and is used to better understand aerodynamic effects of biological corrugation. The aerodynamics associated with a morphologically accurate bee wing geometry are explored in two and three dimensions for the first time. Multiple methodologies are validated with experimental results presented in the literature to capture the fluid dynamics in two dimensions including the Lattice-Boltzmann method and unstructured dynamic remeshing using a Navier-Stokes approach. The effects of wing cross-section are compared first with common geometries used in the literature in two dimensions and then between cross-sections extracted at different locations along the wing span. A three-dimensional methodology is validated and used to compare the true bee wing with one using a rectangular cross-section in symmetric hovering. The influence of spanwise cross-section is revisited in three dimensions and compared to the results found in two-dimensions for the same kinematics in forward flight. The final focus of the dissertation is the first simulation of a morphologically accurate wing using kinematics described in the literature.PHD
15
Frank, Spencer. "Vortex tilting and the enhancement of spanwise flow in flapping wing flight". Honors in the Major Thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/384.
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In summary the tilting mechanism helps to explain the overall flow structure and the stability of the leading edge vortex.; The leading edge vortex has been identified as the most critical flow structure for producing lift in flapping wing flight. Its stability depends on the transport of the entrained vorticity into the wake via spanwise flow. This study proposes a hypothesis for the generation and enhancement of spanwise flow based on the chordwise vorticity that results from the tilting of the leading edge vortex and trailing edge vortex. We investigate this phenomenon using dynamically scaled robotic model wings. Two different wing shapes, one rectangular and one based on Drosophila melanogaster (fruit fly), are submerged in a tank of mineral oil and driven in a flapping motion. Two separate kinematics, one of constant angular velocity and one of sinusoidal angular velocity are implemented. In order to visualize the flow structure, a novel three dimensional particle image velocimetry system is utilized. From the three dimensional information obtained the chordwise vorticity resulting from the vortex tilting is shown using isosurfaces and planar slices in the wake of the wing. It is observed that the largest spanwise flow is located in the area between the chordwise vorticity of the leading edge vortex and the chordwise vorticity of the trailing edge vortex, supporting the hypothesis that the vortex tilting enhances the spanwise flow. Additionally the LEV on the rectangular wing is found to detach at about 80% span as opposed to 60% span for the elliptical wing. Also, two distinct regions of spanwise flow, one at the base and one at the tip, are observed at the beginning of the sinusoidal kinematic, and as the velocity of the wing increases these two regions unionize into one. Lastly, the general distribution of vorticity around each wing is found to be nearly the same, indicating that different wing shapes do not greatly affect the distribution of vorticity nor stability mechanisms in flapping flight.B.S.
Bachelors
Mechanical, Materials, and Aerospace Engineering
Engineering and Computer Science
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Alford, Lionel Devon Jr. "Aerodynamic Analysis of Natural Flapping Flight Using a Lift Model Based on Spanwise Flow". University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1272639883.
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Karasek, Matej. "Robotic hummingbird: design of a control mechanism for a hovering flapping wing micro air vehicle". Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209177.
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The use of drones, also called unmanned aerial vehicles (UAVs), is increasing every day. These aircraft are piloted either remotely by a human pilot or completely autonomously by an on-board computer. UAVs are typically equipped with a video camera providing a live video feed to the operator. While they were originally developed mainly for military purposes, many civil applications start to emerge as they become more affordable.
Micro air vehicles are a subgroup of UAVs with a size and weight limitation; many are designed also for indoor use. Designs with rotary wings are generally preferred over fixed wings as they can take off vertically and operate at low speeds or even hover. At small scales, designs with flapping wings are being explored to try to mimic the exceptional flight capabilities of birds and insects.
The objective of this thesis is to develop a control mechanism for a robotic hummingbird, a bio-inspired tail-less hovering flapping wing MAV. The mechanism should generate moments necessary for flight stabilization and steering by an independent control of flapping motion of each wing.
The theoretical part of this work uses a quasi-steady modelling approach to approximate the flapping wing aerodynamics. The model is linearised and further reduced to study the flight stability near hovering, identify the wing motion parameters suitable for control and finally design a flight controller. Validity of this approach is demonstrated by simulations with the original, non-linear mathematical model.
A robotic hummingbird prototype is developed in the second, practical part. Details are given on the flapping linkage mechanism and wing design, together with tests performed on a custom built force balance and with a high speed camera. Finally, two possible control mechanisms are proposed: the first one is based on wing twist modulation via wing root bars flexing; the second modulates the flapping amplitude and offset via flapping mechanism joint displacements. The performance of the control mechanism prototypes is demonstrated experimentally.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Gaston, Zachary Robert. "Computational Investigation of a Hinge-connected Hovering Plate". Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1344991071.
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Moses, Kenneth C. "Biomimicry of the Hawk Moth, Manduca sexta (L.): Forewing and Thorax Emulation for Flapping-Wing Micro Aerial Vehicle Development". Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case158687503705972.
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Swanson, Taylor Alexander. "An experimental and numerical investigation of flapping and plunging wings". Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Swanson_09007dcc80672efe.pdf.
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Thesis (Ph. D.)--Missouri University of Science and Technology, 2009.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed June 2, 2009) Includes bibliographical references (p. 115-126).
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Khan, Zaeem. "Modeling, optimal kinematics, and flight control of bio-inspired flapping wing micro air vehicles". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 209 p, 2009. http://proquest.umi.com/pqdweb?did=1885675181&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Doan, Le Anh. "Du micro véhicule aérien au nano véhicule aérien : études théoriques et expérimentales sur un insecte artificiel à ailes battantes". Thesis, Valenciennes, 2019. http://www.theses.fr/2019VALE0004/document.
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Au cours des dernières décennies, la possibilité d’exploiter les capacités de vol exceptionnelles des insectes a été à l’origine de nombreuses recherches sur l’élaboration de nano-véhicules aériens (NAVs) à ailes battantes. Cependant, lors de la conception de tels prototypes, les chercheurs doivent analyser une vaste gamme de solutions liées à la grande diversité des insectes volants pour identifier les fonctionnalités et les paramètres adaptés à leurs besoins. Afin d’alléger cette tâche, le but de ce travail est de développer un outil permettant à la fois d’examiner le comportement cinématique et énergétique d’un nano-véhicule aérien à ailes flexibles résonantes, et donc d'évaluer son efficacité. Cet objectif reste néanmoins extrêmement difficile à atteindre car il concerne des objets de très petites tailles. Aussi, nous avons choisi tout d’abord de travailler sur un micro-véhicule aérien (MAV) à ailes battantes. Il s’agit avant tout de valider l’outil de modélisation à travers une comparaison systématique des simulations avec des résultats expérimentaux effectués lors de l’actionnement des ailes, puis au cours du décollage et du vol stationnaire du prototype. Une partie des connaissances et expériences acquises pourra ensuite être utilisée afin de mieux comprendre le fonctionnement et identifier la distribution d'énergie au sein du NAV. Bien que les deux véhicules s’inspirent directement de la cinématique des ailes d'insectes, les mécanismes d'actionnement des ailes artificielles des deux prototypes ne sont pas les mêmes en raison de la différence de taille. Comme le NAV est plus petit, ces ailes ont un mouvement de battement à une fréquence plus élevée que celles du MAV, à l’instar de ce qui existe dans la nature. En conséquence, lorsque l’on passe du MAV au NAV, le mécanisme d’actionnement des ailes doit être adapté et cette différence nécessite d’une part, de revoir la conception, l'approche de modélisation et le processus d'optimisation, et d’autre part, de modifier le procédé de fabrication. Une fois ces améliorations apportées, nous avons obtenu des résultats de simulations en accord avec les tests expérimentaux. Le principal résultat de ce travail concerne l’obtention pour les deux prototypes, le MAV et le NAV, d’une cinématique appropriée des ailes, qui conduit à une force de portance équivalente au poids. Nous avons d’ailleurs démontré que le MAV était capable de décoller et d’avoir un vol stationnaire stable selon l’axe vertical. En tirant parti des modèles basés sur le langage Bond Graph, il est également possible d'évaluer les performances énergétiques de ces prototypes en fonction de la dynamique de l'aile. En conclusion, cette étude contribue à la définition des paramètres essentiels à prendre en compte lors de la conception et l'optimisation énergétique de micro et nano-véhicules à ailes battantesIn recent decades, the prospect of exploiting the exceptional flying capacities of insects has prompted much research on the elaboration of flapping-wing nano air vehicles (FWNAV). However, when designing such a prototype, designers have to wade through a vast array of design solutions that reflects the wide variety of flying insects to identify the correct combination of parameters to meet their requirements. To alleviate this burden, the purpose of this work is to develop a suitable tool to analyze the kinematic and power behavior of a resonant flexible-wing nano air vehicle. The key issue is evaluating its efficiency. However, this ultimate objective is extremely challenging as it is applied to the smallest flexible FWNAV. However, in this work, we worked first with a flapping-wing micro air vehicle (FWMAV) in order to have a tool for the simulation and experimentation of wing actuation, take-off and hovering. Some of the knowledge and experience acquired will then be transferred to better understand how our FWNAV works and identify the energy, power distribution. Although both of the vehicles employ the insect wing kinematics, their wings actuation mechanisms are not the same due to their sizes difference. Since the FWNAV is smaller, their wings flap at a higher frequency than the FWMAV as inspired by nature. As a consequence, from MAV to NAV, the wing actuation mechanism must be changed. Throughout this work, it can be seen clearly that this difference affects the whole vehicles development including the design, the manufacturing method, the modeling approach and the optimizing process. It has been demonstrated that the simulations are in good correlation with the experimental tests. The main result of this work is the proper wing kinematics of both FWMAV and FWNAV which leads to a lift to the weight ratio bigger and equal to one respectively. The FWMAV is even success to take-off and vertically stable hover. Moreover, taking advantage of the Bond Graph-based models, the evolution power according to the wing dynamic and the efficiency of the subsystem can be evaluated. In conclusion, this study shows the key parameters for designing and optimizing efficiency and the lift generated for two flapping wing vehicles in different size regimes
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Faux, Damien. "Couplage modal pour la reproduction de la cinématique d'une aile d'insecte et la génération de portance d'un nano-drone bio-inspiré". Thesis, Valenciennes, 2018. http://www.theses.fr/2018VALE0007/document.
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Cette recherche dans le domaine des nano-drones a pour ambition de concevoir un objet volant de taille réduite s’inspirant directement de la nature.Dans ce but, un état de l’art a été fait sur les mécanismes de vol des insectes ainsi que sur l’ensemble des solutions à ailes battantes artificielles développées à ce jour. Il ressort de cette analyse d’une part, que les insectes ont une cinématique des ailes singulière reposant sur un mouvement de battement et de torsion en quadrature de phase et d’autre part, que les nano-drones actuels ne s’appuient pas ou très peu sur le comportement dynamique de leurs ailes artificielles pour générer de la portance. Le concept proposé dans le cadre de ce travail se veut en rupture avec ces approches. Il consiste en un couplage vibratoire en quadrature de phase de modes de battement et de torsion appliqué sur des ailes artificielles flexibles afin de reproduire une cinématique proche de celles des insectes avec un unique actionneur. La méthodologie employée s’est traduite par l’élaboration d’un modèle analytique négligeant les efforts aérodynamiques afin de calculer le comportement dynamique et de dimensionner la structure du nano-drone. Les simulations ont mis en évidence l’existence de modes propres de la structure des ailes dont les déformées correspondent aux mouvements de battement et de torsion recherchés. Fait remarquable, une optimisation a permis de rapprocher les fréquences de ces modes tout en conservant une amplitude suffisante de façon à réaliser leur couplage et donc à reproduire la cinématique souhaitée. La portance produite a été ensuite estimée à l’aide d’un modèle aéroélastique qui a montré que le maximum de portance était obtenu pour deux fréquences coïncidant avec une quadrature de phase entre les deux modes. Ces résultats ont par la suite été confirmés à l’aide de mesures expérimentales effectuées sur un banc de mesure spécifique répondant aux contraintes imposées par les prototypes en termes de sensibilité et de comportement dynamique. Les différentes générations de prototypes testées ont été fabriquées au moyen des procédés de microfabrication, ce qui a permis l’intégration d’une membrane d’aile en parylène d’une épaisseur tout à fait comparable à celle existant chez les insectes. La conclusion de cette étude est que nous disposons dorénavant d’un prototype capable de compenser son poidsThis work in the Nano-Air Vehicle field aims to design a small flying object directly inspired by the nature. For this purpose, a state of the art has been performed on insects flight mecanisms and has reviewed the overall artificial flapping wings solutions developped until today. The result of this analysis is on one hand, that insects use a specific wing kinematics which relies on a flapping motion and a twisting motion coupled in a quadrature phase shift and on the other hand, that the existing Nano-Air Vehicles do not exploit the dynamic behavior of their artificial wings to produce lift. The proposed concept in this research is a departure from those other works. It consists of a vibratory coupling in a quadrature phase shift of a flapping and a twisting mode applied on flexible artificial wings in order to reproduce a kinematics close to the insects ones with a single actuator. The used methodology resulted in the development of an analytic modeling which neglects the aerodynamic forces to calculate the dynamic behavior and dimension the prototype structure. Simulations highlighted the existence of eigen modes of the wings structure whose modal shapes match with the wanted flapping and twisting motion. Noteworthy fact, an optimization allowed to get those modes close in frequency while keeping a non-neglectible amplitude in such a way as to couple them and obtain the expected kinematics. The produced lift force is then estimated with an aeroelastic modeling which has shown that the maximum lift is obtained for two frequencies which provide a quadrature phase shift between the two modes. Those results are then validated by experimental measurements performed on a specific bench made according to the constraints due to the prototype in terms of sensitivity and dynamic behavior. The different generations of prototypes tested are produced with microfabrication process, allowing to integrate a wing membrane in parylene with a thickness comparable to the one existing in insects. The conclusion of this study is that we now have a prototype able to compensate its weight
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Vanneste, Thomas. "Développement d'un outil de modélisation aéroélastique du vol battu de l'insecte appliqué à la conception d'un nano-drone résonant". Thesis, Valenciennes, 2013. http://www.theses.fr/2013VALE0021/document.
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Développer, à partir de zéro, un drone imitant le vol battu de l'insecte est une tâche ambitieuse et ardue pour un designer en raison du manque de savoir-faire en la matière. Pour en accélérer le développement pendant les phases de design préliminaires, un outil modélisant les phénomènes aéroélastiques du vol de l'insecte est un véritable atout pour le designer et est le sujet de cette thèse. Le cœur de cet outil est un solveur éléments finis 'structure' couplé, en utilisant une approche par tranche, à un modèle aérodynamique quasi-statique du vol de l'insecte prenant en compte la flexibilité de l'aile, à la fois selon l'envergure et la corde, mais aussi ses grands déplacements. L'ensemble est conçu de manière à contenir le coût de calcul tout en étant assez modulaire pour s'adapter à un large panel d'applications. Afin de valider l'intégralité de cet outil, un processus en deux étapes a été entrepris avec d'abord une approche numérique et ensuite une validation expérimentale grâce à un banc de caractérisation dédié. Les résultats du modèle concordent de manière satisfaisante dans les deux cas, capturant l'amortissement dû aux forces aérodynamiques, et ouvrent ainsi la voie à son utilisation pour le design de drones à ailes battantes. Pour démontrer l'intérêt de cette approche lors des phases de design préliminaires, deux applications sur un nano-drone résonant sont réalisées: la définition d'une stratégie d'actionnement efficace et la recherche d'une géométrie d'aile potentiellement intéressante d'un point de vue aérodynamique, en couplant l'outil de modélisation à un algorithme génétique. Les résultats obtenus sont cohérents avec ceux trouvés dans la nature et sont en cours d'implémentation sur le droneDeveloping insect-like flapping-wing drones from scratch is an ambitious and arduous task for designers due to a lack of well-established know-how. To speed up the development of such vehicles through the preliminary design stage, a framework modeling the aeroelastic phenomena encountered in insect flight is an asset and is the subject of this thesis. Its kernel is a FEM based structural solver coupled in a blade-element approach to a quasi-steady aerodynamic model of insect flight accounting for the wing flexibility, both in the spanwise and in the chordwise direction, and for its large displacement. The complete framework is devised so as to maintain the computation load low while being modular enough for a wide range of applications. To validate the overall aeroelastic framework, a two-steps process has been undertaken with in one hand numerical studies and in the other hand experimental ones acquired on a dedicated test bench. The framework computation agrees satisfactorily, capturing the damping due to the aerodynamic force, and thus paves the way for preliminary design applications of a flapping-wing vehicle. To exhibit the capabilities of the framework as a preliminary design tool, two applications on a resonant nano air vehicle are performed: the definition of an efficient actuation strategy and the search of an aerodynamic potentially interesting wing geometry by plugging the framework to a genetic algorithm. The results are coherent with the ones found in nature and are under implementation on the nano air vehicle
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Bontemps, Alexandre. "Prototypage d'un objet volant mimant l'insecte". Thesis, Valenciennes, 2013. http://www.theses.fr/2013VALE0030/document.
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Ce travail de thèse s'inscrit dans le contexte des drones vise à réaliser à terme un Nano-dispositif volant (Nano Aerial Vehicle) capable d'imiter le vol des insectes. Ce mode de locomotion est privilégié car il présente des caractéristiques très adaptées au vol en milieu confiné. La solution proposée consiste à développer un drone de la taille d'un insecte s'appuyant sur des ailes vibrantes pour se mouvoir et à utiliser les technologies MEMS pour répondre aux problématiques de fabrication et de réduction d'échelle. La réussite d'un tel projet soulève néanmoins de nombreux défis scientifiques et technologiques, en particulier, les aspects aéro-élastiques des ailes et l'autonomie du drone. Pour répondre à ces défis, nous proposons dans un premier temps de mettre en œuvre des concepts comme la résonance et la torsion passive sur des prototypes en polymère (SU-8) réalisés par photolithographie. Dans un second temps, les différents composants de la chaîne de puissance sont optimisés, notamment l'actionneur électromagnétique, la liaison et les ailes de manière à maximiser la force de portance générée. Suite à ces améliorations, nous démontrons de façon expérimentale que le prototype était capable non seulement de reproduire une cinématique complexe mais également de compenser 75% de son poidsThis manuscript reports a work which aims to develop a tiny flying robots inspired by natural flyers. Our main objective is to devise a flying robot mimicking insects in terms of kinematics and scale using MEMS technologies in order to answer the scale challenges: the large-scale manufacturing and the system's small scale. The success this project faces different challenges such as aeroelastic aspects of wings and drone autonomy.In this work we propose the use of original concepts like resonance and passive torsion of the wings which are implemented on all-polymer prototypes obtained using a micromachining SU-8 photoresist process. In order to achieve a better efficiency of the prototype, each element of the energy transduction has been carefully examined and optimized. Especially, the actuation, the transmission and the wings in order to increase the lift. These improvements demonstrate experimentally that the prototype is able to produce a complex kinematic and compensate 75 % of its weight
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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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(9754904), Jesse A. Roll. "Principles & Applications of Insect Flight". Thesis, 2020.
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Insects are the most successful animal on the planet, undergoing evolutionary adaptions in size and the development of flight that have allowed access to vast ecological niches and enabled a means by which to both prey and escape predation. Possessing some of the fastest visual systems on the planet, powerful sets of flight muscles, and mechanosensors tuned to perceive complex environments in high-fidelity, they are capable of performing acrobatic maneuvers at speeds that far exceed that of any engineered system. In turn, stable flight requires the coordinated effort of these highly specialized flight systems while performing activities ranging from evasive flight maneuvers to long-distance seasonal migrations in the presence of adverse flow conditions. As a result, the exceptional flight performance of flying insects has inspired a new class of aerial robots expressly tailored to exploit the unique aerodynamic mechanisms inherent to flapping wings. Over the course of three research studies, I explore new actuation techniques to address limitations in power and scalability of current robot platforms, develop new analytical techniques to aid in the design of insect-inspired robot flapping wings, and investigate attributes of flapping wing aerodynamics that allow insects to overcome the difficulties associated with flight in turbulent flow conditions, in an effort to advance the science of animal locomotion.
Recent advancements in the study of insect flight have resulted in bio-inspired robots uniquely suited for the confined flight environments of low Reynolds number flow regimes. Whereas insects employ powerful sets of flight muscles working in conjunction with specialized steering muscles to flap their wings at high frequencies, robot platforms rely on limited sets of mechanically amplified piezoelectric actuators and DC motors mated with gear reductions or linkage systems to generate reciprocating wing motion. As a result, these robotic systems are typically underactuated - with wing rotation induced by inertial and aerodynamic loading - and limited in scale by the efficiency of their actuation method and the electronics required for autonomous flight (e.g., boost converters, microcontrollers, batteries, etc.). Thus, the development of novel actuation techniques addressing the need for scalability and use of low-power components would yield significant advancements to the field of bio-inspired robots. As such, a scalable low-power electromagnetic actuator configurable for a range of resonant frequencies was developed. From physics-based models capturing the principles of actuation, improvements to the electromagnetic coil shape and a reconfiguration of components were made to reduce weight and increases overall efficiency. Upon completion of a proof-of-concept prototype, multiple actuators were then integrated into a full-scale robot platform and validated through a series of free flight experiments. Design concepts and modeling techniques established by this study have since been used to develop subsequent platforms utilizing similar forms of actuation, advancing the state-of-art in bio-inspired robotics.
With the ability to make instantaneous changes in mid-flight orientation through subtle adjustments in angle-of-attack, the maneuverability of flying insects far exceeds that of any man-made aircraft. Yet, studies on insect flight have concluded that the rotation of insect wings is predominately passive. Coincidentally, bio-inspired flapping wing robots almost universally rely on passive rotational mechanisms to achieve desired angles-of-attack - a compromise between actuator mass and the controllable degrees-of-freedom that results in underactuated flight systems. For many platforms, the design of passive mechanisms regulating the rotational response of the wing is determined from either simulations of the wing dynamics or empirically derived data. While these approaches are able to predict the wing kinematics with surprising accuracy, they provide little insight into the effects that wing parameters have on the response or the aerodynamic forces produced. Yet, these models establish a means by which to both study insect flight physiology and explore new design principles for the development of bio-inspired robots. Using a recent model of the passively rotating insect wing aerodynamics, a novel design principle used to tune the compliance of bio-inspired robot wings is developed. Further, through the application of nonlinear analysis methods, parameters optimizing lift production in flapping wings is identified. Results from this analysis are then validated experimentally through tests preformed on miniature flapping wings with passive compliant hinges. This work provides new insight into the role passive rotational dynamics plays in insect flight and aids in the development future flapping wing robots.
Insect flight is remarkably robust, enabling myriad species to routinely endure adverse flow environments while undergoing common foraging activities and long-distance migratory flights. In contrast to the laminar (or smooth) flow conditions of high-altitude flights by commercial aircraft, insect flight occurs within the lower atmosphere where airflows are unsteady, and often turbulent. Yet despite the substantial challenge these conditions pose to an insect's physiology, flights spanning entire continents are common for numerous migratory species. To investigate how insects sustain stable flight under fluctuating flow conditions, the aerodynamic forces and flows produced by a dynamically scaled robotic insect wing immersed in a specially devised turbulence tank were examined. Despite variation in aerodynamic forces generated between wing strokes, results show that the averaged force from flapping remains remarkably steady under turbulent conditions. Furthermore, measurements of the flows induced by the wing demonstrated that unsteady aerodynamic forces generated by flying insects actively buffer against external flow fluctuations. These results provide mechanistic evidence that insect flight is resilient to turbulent conditions, and establishes principles that aid in the development of insect-inspired robots tailored for flight in adverse flow environments.
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Hang, Liang-Tong, i 杭亮同. "Numerical simulation of 3-D flapping-wing insect''s hovering flight under gust wind situations". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/13845357760457815015.
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碩士淡江大學
航空太空工程學系碩士班
102
Title of Thesis: Total pages: 76 Numerical simulation of 3-D flapping-wing insect''s hovering flight under gust wind situations Keywords: 3-D Flapping Wing, Dynamic Mesh, Gust, UDF Name of Institute: Graduate Institute of Aerospace Engineering, Tamkang University Graduate Date: June 2014 Degree Conferred: Master Name of Student: Liang-Tong Hang Advisor: Dr. Tung Wan 杭亮同 宛 同 博士 Abstract: With advance of science and technology, the development of aerospace technology progress fast. Flapping-wing is a popular and innovative topic. Based on Darwin''s theory of evolution; we can have a general interpretation of each biological behavior patterns are the results of optimization. So it is important to combines aerodynamics and Bionics. Many researchers put effort into study the unsteady aerodynamics and flapping flight but study in flapping-wing Affected by atmospheric environment is much less. Our research team has studied the impact of weather factors for a long time and extensive lots experience in the analysis of different climatic conditions. In this thesis, we will discuss effect of flapping wings for aerodynamics in different gust. Here we use the dynamic grid mechanism of commercial software ANSYS / FLUNET to simulate flapping-wings, edit UDF in C++ and combine Solver to analysis aerodynamic performance under gust. First, we finish the validation of 2-D elliptic flapping wing section with Wang, J. We build 3D model butterfly which species is Morpho peleides Butler by PRO-E. From the morphological data of Morpho peleides is measured by Dudley. We generate mesh by Gambit and ANSYS and use dynamic mesh mechanism of ANSYS / FLUNET to simulate the butterfly forward flight. According to Liang and Yang, we create two type of the gust function with single and multiple frequencies. We analysis the butterfly under different gust and different directions and find lift coefficient is sensitive for the gust from top and bottom. The mean value of lift coefficient can be increased more than tenfold compared with the case without wind effects. And since the assumptions we make, our results may occur tolerance in quantitative values but it is worth referencing in Qualitative physical interpretation. If possible, consider the pitching oscillation of body and the flapping-wing with flexible in the future will improve accuracy of the results.
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Cheng, Yuan-Tai, i 鄭元泰. "On the simulation of 3-D flapping-wing insect''s flight performance under abnormal atmospheric conditions". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/79824649727494952987.
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碩士淡江大學
航空太空工程學系碩士班
102
In recent years, flapping wing technology is becoming more popular, and Micro Air Vehicle (MAV) has received great attention from researchers. For most people their desired MAV performance is limited in the flapping mode of small birds and insects under clear weather situation. But in past years Taiwan has experienced many disasters caused by detrimental and severe weather, such as extremely heavy rain and very thick fog. In such cases if MAV could put into use to help the rescue mission, it could significantly improve the efficiency of rescue. However, the insect-like MAV is very small and light, and it''s very sensitive to sudden change of atmospheric surroundings. Therefore, maintain the flapping wing MAV flight quality in extreme weather will be an important issue. In this study, we constructed a geometric model of the butterfly based on a true Morpho peleides and created a grid system by GAMBIT and ANSYS preprocessing software, then use the CFD software FLUENT combine with the User Define Function (UDF) to analyze the relationship between the flow field and other aerodynamic phenomenon. For our simulation, we programing a grid convergence process first to verify the simulation of our 3-D butterfly flapping motion, and the flapping-wing aerodynamic parameters such as lift coefficient and drag coefficient are almost same with four grid systems in clam atmospheric condition. According to several cases, we can find some result. When the butterfly increases the pitch angle of flapping motion in forward flight, the lift coefficient will increase too. Then the trend of the lift coefficient curve will more approximate with the lift coefficient of the true butterfly in forward flight. In our abnormal atmospheric cases, we used the Discrete Particles Model (DPM) in FLUENT to simulate the 3-D butterfly flapping motion in heavy rain condition. In our result, the average values of lift coefficient under the heavy rain condition are lower than the case in normal atmospheric condition. When the liquid water content (LWC) is 25 g/m3, the reduction rate of lift coefficient would be reduced to 60.389% from 618.6% with the rising angle of attack. In the situation of the liquid water content is 39 g/m3, the reduction rate of lift coefficient will decrease from 1057% to 101.537% with the gradual increase in the angle of attack. Therefore, the effect of the heavy rain can be relieved by changing the angle of attack in forward flight, and the higher angle of attack can relieve more impact of heavy rain.