Download or read book Optimisation of the Kinematics of Flapping Airfoils for Micro Air Vehicle Applications written by Houssam Soueid and published by . This book was released on 2008 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: The optimisation of the kinematics of a two-dimensional flapping airfoil is carried out by numerical simulation to identify flapping parameters capable to ensure high aerodynamic performances for a micro air vehicle application. Attention is focused on the lift and thrust and on the propulsive efficiency. The control variables are the amplitudes of the combined motions of heaving and pitching and the phase angle between them. Additionally, the flapping frequency and the mean angle of attack are considered. The optimal kinematics are compared to observations in nature on birds, insects and fish. The methodology is based on the solution of the flow field around a NACA0012 airfoil submitted to translational and angular oscillations. Then, the gradients of the cost functional with respect to the control parameters are evaluated thanks to the sensitivity technique and the complex step derivative method. The gradients are subsequently used in a quasi-Newton update algorithm to direct the solution towards its optimal value. Results show the ability of optimised flapping airfoils to produce large thrust and lift, with an acceptable efficiency. This is ensured when the pitching oscillations lead the heaving ones by a phase angle close to 90o and when the Strouhal number of oscillations is in the range [0.2, 0.4]. It is expected that the optimal efficiency would increase for higher Reynolds number, without much variation in the optimal kinematics. Furthermore, the drop in efficiency at high thrust forces may be limited by including higher order terms in the expression of heaving.

Download or read book Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications written by Thomas J. Mueller and published by AIAA. This book was released on 2001 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title reports on the latest research in the area of aerodynamic efficency of various fixed-wing, flapping wing, and rotary wing concepts. It presents the progress made by over fifty active researchers in the field.

Download or read book Design and Analysis of a Flapping Wing Mechanism for Optimization written by Ryan Brandon George and published by . This book was released on 2011 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Furthering our understanding of the physics of flapping flight has the potential to benefit the field of micro air vehicles. Advancements in micro air vehicles can benefit applications such as surveillance, reconnaissance, and search and rescue. In this research, flapping kinematics of a ladybug was explored using a direct linear transformation. A flapping mechanism design is presented that was capable of executing ladybug or other species-specific kinematics. The mechanism was based on a differential gear design, had two wings, and could flap in harsh environments. This mechanism served as a test bed for force analysis and optimization studies. The first study was based on a Box-Behnken screening design to explore wing kinematic parameter design space and manually search in the direction of flapping kinematics that optimized the objective of maximum combined lift and thrust. The second study used a Box-Behnken screening design to build a response surface. Using gradient-based techniques, this surface was optimized for maximum combined lift and thrust. Box-Behnken design coupled with response surface methodology was an efficient method for exploring the mechanism force response. Both methods for optimization were capable of successfully improving lift and thrust force outputs. The incorporation of the results of these studies will aid in the design of more efficient micro air vehicles and with the ultimate goal of leading to a better understanding of flapping wing aerodynamics and the development of aerodynamic models.

Download or read book Experimental Characterization Design Analysis and Optimization of Flexible Flapping Wings for Micro Air Vehicles written by Pin Wu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT:This work has advanced the understanding of flapping flight of flexible wings designed to be used in micro air vehicles. A complete new experimental setup that includes a wing actuation mechanism, a customized digital image correlation system, a control system, a load sensor and a vacuum chamber is realized for this study. The technique of digital image correlation has also been developed so that complicated wing kinematics and deformation can be measured. The flapping wing effectiveness and efficiency have been evaluated in different conditions. The results indicate that passive wing deformation can be utilized to enhance aerodynamic performance, under certain inertial loading mainly dictated by flapping frequency, amplitude, wing compliance and mass distribution. The wing deformation reflects the aeroelastic effect produced by the coupled aerodynamic loading as well as the inertial loading. Critical parameters extracted from the deformation data are used to characterize the structural properties of the wings and correlate with the aerodynamic performance. The correlation shows that for one-degree-of-freedom kinematics, wing deformation can be directly used to predict time averaged thrust. The intrinsic relationship between kinematics and inertial loading enables the design and optimization of wing structure based on the correlation results.

Download or read book Aerodynamic Efficiency of Flapping Wings Applied to Micro and Nano Aerial Vehicles written by Salomon Maestas and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this thesis is to devise a method for optimizing hovering efficiency in flapping-wing aerial vehicles (FWAV) and then to extend the study to include the effect of color on flapping aerodynamic efficiency. The thesis is divided into four chapters; (1) an introduction to Unmanned Aerial Vehicles (UAV), (2) a detailed discussion of flapping-wing aerial vehicles, (3) a method for optimizing flapping-wing aerial vehicles, and (4) a study of the effect of color on flapping-wing aerodynamic efficiency. In Chapter 1, different types of drones and their applications are discussed. In Chapter 2, the design process, aerodynamics, as well as flight mechanisms of flapping-wing drones are presented.In Chapter 3, five different bird wing shapes with hovering capability are investigated, and their kinematics optimized for application in flapping-wing micro air vehicles (FWMAV). First, applying least square curve fitting, two polynomial functions are derived for the leading and trailing edge of each wing. Using these polynomial functions, geometric parameters of aspect ratio, the second and third moment of inertia, and the mean aerodynamic chord are calculated. The Gradient method is then used to determine the optimal pitch and flapping angle amplitude, which in turn provide the minimum aerodynamic power necessary to satisfy the hovering motion constraint for each wing.

Download or read book Progress in Astronautics and Aeronautics written by and published by . This book was released on 2001 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optimization of the Aerodynamics of Small scale Flapping Aircraft in Hover written by Sidney Lebental and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Flapping flight is one of the most widespread mean of transportation. It is a complex unsteady aerodynamic problem that has been studied extensively in the past century. Nevertheless, by its complex nature, flapping flight remains a challenging subject. With the development of micro air vehicles, researchers need new computational methods to design these aircrafts efficiently. In this dissertation, I will present three different methods of optimization for flapping flight with an emphasis on hovering with each their advantages and drawbacks. The first method was developed by Hall et al. It is an extremely fast and powerful three-dimensional approach. However, the assumptions made to develop this theory limit its use to lightly loaded wings. In addition, it only models the motion of the trailing edge and not the actual motion of the wing. In a second part, I will present a two-dimensional unsteady potential method. It uses a freely convected wake which removes the lightly loaded restriction. This method shows the existence of an optimal combination of plunging and pitching motion. The motion is optimal in the sense that for a required force vector, the aerodynamic power is minimal. The last method incorporates the three-dimensional effects. These effects are especially important for low aspect ratio wings. Thus, a three-dimensional unsteady potential vortex method was developed. This method also exhibits the presence of an optimal flapping/pitching motion. In addition, it agrees really well with the two previous methods and with the actual kinematics of birds during hovering flapping flight. To conclude, some preliminary design tools for flapping wings in forward and hovering flight are presented in this thesis.

Download or read book The DelFly written by G.C.H.E. de Croon and published by Springer. This book was released on 2015-11-26 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the topics most relevant to autonomously flying flapping wing robots: flapping-wing design, aerodynamics, and artificial intelligence. Readers can explore these topics in the context of the "Delfly", a flapping wing robot designed at Delft University in The Netherlands. How are tiny fruit flies able to lift their weight, avoid obstacles and predators, and find food or shelter? The first step in emulating this is the creation of a micro flapping wing robot that flies by itself. The challenges are considerable: the design and aerodynamics of flapping wings are still active areas of scientific research, whilst artificial intelligence is subject to extreme limitations deriving from the few sensors and minimal processing onboard. This book conveys the essential insights that lie behind success such as the DelFly Micro and the DelFly Explorer. The DelFly Micro, with its 3.07 grams and 10 cm wing span, is still the smallest flapping wing MAV in the world carrying a camera, whilst the DelFly Explorer is the world's first flapping wing MAV that is able to fly completely autonomously in unknown environments. The DelFly project started in 2005 and ever since has served as inspiration, not only to many scientific flapping wing studies, but also the design of flapping wing toys. The combination of introductions to relevant fields, practical insights and scientific experiments from the DelFly project make this book a must-read for all flapping wing enthusiasts, be they students, researchers, or engineers.

Download or read book Force Optimization and Flow Field Characterization from a Flapping Wing Mechanism written by Nathaniel Stephen Naegle and published by . This book was released on 2012 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flapping flight shows promise for micro air vehicle design because flapping wings provide superior aerodynamic performance than that of fixed wings and rotors at low Reynolds numbers. In these flight regimes, unsteady effects become increasingly important. This thesis explores some of the unsteady effects that provide additional lift to flapping wings through an experiment-based optimization of the kinematics of a flapping wing mechanism in a water tunnel. The mechanism wings and flow environment were scaled to simulate the flight of the hawkmoth (Manduca sexta) at hovering or near-hovering speeds. The optimization was repeated using rigid and flexible wings to evaluate the impact that wing flexibility has on aerodynamic performance of flapping wings. The trajectories that produced the highest lift were compared using particle image velocimetry to characterize the flow features produced during the periods of peak lift. A leading edge vortex was observed with all of the flapping trajectories and both wing types, the strength of which corresponded to the measured amount of lift of the wing. This research furthers our understanding of the lift-generating mechanisms used in nature and can be applied to improve the design of micro air vehicles.

Download or read book Frontiers in PDE Constrained Optimization written by Harbir Antil and published by Springer. This book was released on 2018-10-12 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a broad and uniform introduction of PDE-constrained optimization as well as to document a number of interesting and challenging applications. Many science and engineering applications necessitate the solution of optimization problems constrained by physical laws that are described by systems of partial differential equations (PDEs)​. As a result, PDE-constrained optimization problems arise in a variety of disciplines including geophysics, earth and climate science, material science, chemical and mechanical engineering, medical imaging and physics. This volume is divided into two parts. The first part provides a comprehensive treatment of PDE-constrained optimization including discussions of problems constrained by PDEs with uncertain inputs and problems constrained by variational inequalities. Special emphasis is placed on algorithm development and numerical computation. In addition, a comprehensive treatment of inverse problems arising in the oil and gas industry is provided. The second part of this volume focuses on the application of PDE-constrained optimization, including problems in optimal control, optimal design, and inverse problems, among other topics.

Download or read book Wing Force Moment Characterization of Flapping Wings for Micro Air Vehicle Application written by and published by . This book was released on 2005 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents a general method for investigating the unsteady aerodynamics of flapping wings for micro air vehicle application. For this purpose, a dynamically scaled robotic flapper was designed and fabricated which can flap the wings in a desired kinematic pattern. A quasisteady aerodynamic model and wing testing methodology was developed based on unsteady aerodynamic mechanisms. This model additionally accounts for the wing twisting. The experimental results show a good agreement with published data. 24 kinematic patterns were tested and the quasi-steady aerodynamic model compares well with the experimental results. The focus of the present work is on hovering flight, however, the methodology is general and can be extended to slow forward flight in future.

Download or read book Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications Micro air vehicle applications written by T. J. Mueller and published by . This book was released on 2001 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications Flapping and rotary wing aerodynamics written by T. J. Mueller and published by . This book was released on 2001 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Unsteady Aerodynamics Relevant to Insect inspired Flapping wing Micro Air Vehicles written by Nahid Phillips and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Flapping Wing Design for a Dragonfly like Micro Air Vehicle written by Daniel T. Prosser and published by . This book was released on 2011 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis, the aerodynamics of the Quad-Wing Vehicle, a Micro Air Vehicle designed to hover with four flapping wings in a dragonfly-like configuration, is investigated using Computational Fluid Dynamics (CFD), potential flows analysis, and experimental testing. The CFD analysis investigates the kinematics-parameters design space and identifies values of kinematics parameters that maximize the vertical force reduction in hovering mode while minimizing the aerodynamic power requirement. It also investigates other important considerations, such as the effect of scaling, multi-wing interactions, and comparison with other flapping configurations. In the potential flows analysis , an unsteady 2D panel code is developed and compared with CFD for a broad range of hovering-flight simulations. The results show that, with further development, panel codes may be useful to designers of hovering flapping MAVs because of their time-saving potential compared to CFD. The experimental testing focuses on isolating the aerodynamic forces from other measured forces on a benchtop flapping device, and the findings of the experimental study will be useful for later researchers using experimental methods to study flapping MAV aerodynamics."--Abstract.

Download or read book Unsteady Separated Flowfields Surrounding a Flapping Airfoil written by Keith Gray and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comprehensive Modeling and Control of Flexible Flapping Wing Micro Air Vehicles written by Stephen Michael Nogar and published by . This book was released on 2015 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work highlights the importance of coupled dynamics in the design and control of flapping wing micro air vehicles. Future enhancements to this work should focus on the reduced order structural and aerodynamics models. Applications include using the developed dynamics model to evaluate other kinematics and control schemes, ultimately enabling improved vehicle and control design.