Advanced UAV Aerodynamics, Flight Stability and Control (eBook)

Novel Concepts, Theory and Applications

Pascual Marqués, Andrea Da Ronch (Herausgeber)

eBook Download: EPUB

2017
John Wiley & Sons (Verlag)
978-1-118-92870-7 (ISBN)

Infos

Comprehensively covers emerging aerospace technologies 

Advanced UAV aerodynamics, flight stability and control: Novel concepts, theory and applications presents emerging aerospace technologies in the rapidly growing field of unmanned aircraft engineering. Leading scientists, researchers and inventors describe the findings and innovations accomplished in current research programs and industry applications throughout the world. Topics included cover a wide range of new aerodynamics concepts and their applications for real world fixed-wing (airplanes), rotary wing (helicopter) and quad-rotor aircraft.

The book begins with two introductory chapters that address fundamental principles of aerodynamics and flight stability and form a knowledge base for the student of Aerospace Engineering. The book then covers aerodynamics of fixed wing, rotary wing and hybrid unmanned aircraft, before introducing aspects of aircraft flight stability and control.

Key features:

• Sound technical level and inclusion of high-quality experimental and numerical data.
• Direct application of the aerodynamic technologies and flight stability and control principles described in the book in the development of real-world novel unmanned aircraft concepts.
• Written by world-class academics, engineers, researchers and inventors from prestigious institutions and industry.

The book provides up-to-date information in the field of Aerospace Engineering for university students and lecturers, aerodynamics researchers, aerospace engineers, aircraft designers and manufacturers.

Dr. Pascual Marqués, President of Marques Aviation Ltd., UK holds an MPhil and a PhD degree in Engineering Mechanics. At Marques Aviation, Dr. Marqués oversees the design, R&D, and manufacturing of the MA THOR unmanned aircraft series. His research interests lie in the fields of Aerodynamics at low Reynolds numbers and Flight Stability. His research projects involve the implementation of theoretical aerodynamics. Wing aerodynamic efficiency in UAVs is optimized by adjustment of wing planform and Oswald efficiency, incorporation of flow control devices, modification of tip vortex configuration, and application of optimized geometric and/or aerodynamic twist. Flight stability is enhanced using principles of aeroelasticity, adaptive wing technology, and automated flight control. Dr. Marqués is the Editor-in-Chief of the International Journal of Unmanned Systems Engineering, and Chair of the World Congress on Unmanned Systems Engineering and the International Aerospace Engineering Conference.

Dr. Andrea Da Ronch, University of Southampton, UK
Alongside the academic position at the University of Southampton, Dr Andrea Da Ronch is seconded to Airbus Operations Ltd through a Royal Academic of Engineering grant. He is also a visiting academic at Beihang University (Beijing, China) and at Pontif??cia Universidade Católica do Rio Grande do Sul (Porto Alegre, Brazil). His research interests are in CFD methods for aeroelasticity and flight dynamics, and in the development of nonlinear model reduction techniques for large computational models. The impact of his research activities has a significant international visibility within the aeroelastic and aircraft design communities, reflecting his key role in the development of a number of software tools. The initial involvement with the 'Next generation Conceptual Aero-Structural Sizing' (NeoCASS) has now been superseded by an active role in the development of the 'Computerised Environment for Aircraft Synthesis and Integrated Optimisation Methods' (CEASIOM) software, considered as one of the world's most advanced tools for multi-fidelity integrated aircraft design.

Inhalt

List of Contributors xi

Series Preface xiii

Preface xv

Companion Website xvii

1 Advanced UAV Aerodynamics, Flight Stability and Control: An Introduction 1
Pascual Marqués

2 Aerodynamics of UAV Configurations 31
Pascual Marqués

Part I Novel Concepts in Unmanned Aircraft Aerodynamics 47

1.1 Fixed-wing (airplanes) 47

3 Aerodynamic Performance Analysis of Three Different Unmanned Re?]entry Vehicles 49
Giuseppe Pezzella and Antonio Viviani

4 Nonlinear Reduced?]order Aeroservoelastic Analysis of Very Flexible Aircraft 143
Nikolaos D. Tantaroudas and Andrea Da Ronch

5 Unmanned Aircraft Wind Tunnel Testing 181
R. Bardera Mora

6 Chord?]dominated Ground?]effect Aerodynamics of Fixed?]wing UAVs 201
Qiulin Qu and Ramesh K. Agarwal

1.2 Rotary?]wing (helicopter) 255

7 Dynamics Modelling and System Identification of Small Unmanned Helicopters 257
Cunjia Liu and Wen?]Hua Chen

8 Aerodynamic Derivative Calculation Using Radial Basis Function Neural Networks 283
Ranjan Ganguli

9 Helicopter BERP Tip: Literature Review of Helicopter Blade Shape Optimisation Methods 309
Catherine S. Johnson, Mark Woodgate and George N. Barakos

10 Framework for the Optimisation of a Helicopter Rotor Blade with an Approximate BERP Tip: Numerical Methods and Application 345
Catherine S. Johnson, Mark Woodgate and George N. Barakos

11 Active Blade Twist in Rotary UAVs using Smart Actuation 399
Pascual Marqués

1.3 Hybrid Aircraft 421

12 Hybrid Aircraft Aerodynamics and Aerodynamic Design Considerations of Hover?]to?]Dash Convertible UAVs 423
Ron Barrett

Part II Novel Concepts in Unmanned Aircraft Flight Stability and Control 447

2.1 Fixed-wing (airplanes) 447

13 Closed?]loop Active Flow Control for UAVs 449
Oksana Stalnov

14 Autonomous Gust Alleviation in UAVs 465
Ya Wang and Daniel J. Inman

15 Virtual Flight Simulation using Computational Fluid Dynamics 495
Ubaidullah Akram, Marco Cristofaro and Andrea Da Ronch

16 Flow Structure Modification Using Plasma Actuation for Enhanced UAV Flight Control 547
Antonio J. Conesa Torres

17 Constrained Motion Planning and Trajectory Optimization for Unmanned Aerial Vehicles 577
Seid H. Pourtakdoust and Jalal Karimi

18 Autonomous Space Navigation Using Nonlinear Filters with MEMS Technology 613
Seid H. Pourtakdoust and Maryam Kiani

19 Adaptive Fault?]tolerant Attitude Control for Spacecraft Under Loss of Actuator Effectiveness 645
Qinglei Hu, Bing Xiao, Bo Li and Youmin Zhang

2.2 Quad?]rotor Aircraft 667

20 Novel Concepts in Multi?]rotor VTOL UAV Dynamics and Stability 669
Emaid A. Abdul Retha

21 System Identification and Flight Control of an Unmanned Quadrotor 695
Wei Wei, Mark B. Tischler, Nicholas Schwartz and Kelly Cohen

Index 729

Textauszug

1
Advanced UAV Aerodynamics, Flight Stability and Control: An Introduction

Pascual Marqués

Marques Aviation Ltd, Southport, UK

‘For some years I have been afflicted with the belief that flight is possible to man.’

Wilbur Wright, 13 May 1900.

This introductory chapter is divided into two main sections: Section 1.1 on unmanned aircraft aerodynamics and Section 1.2 on flight stability, and control. The chapter addresses fundamental principles of aerodynamics, flight stability and control and forms a knowledge base for the student of aerospace engineering before proceeding to more advanced chapters in this book. The chapter includes classroom problems.

1.1 Unmanned Aircraft Aerodynamics

1.1.1 Introduction: UAV Categories and Configurations

Unmanned aerial vehicle (UAV) size categories range from nano air vehicles (NAV) with a wing span of only 4 cm to high‐altitude long‐endurance (HALE) aircraft with a wing span of 35 m or more. In between, UAV categories include micro (MAV), mini, close‐range, medium‐range or tactical and medium‐altitude long‐endurance (Figure 1.1). The fluid medium in which an NAV operates is highly viscous, whereas the fluid flow around large (normally manned) aircraft is dominated by inertial effects. Consequently, aerodynamic characteristics vary considerably according to the size of the vehicle.

Figure 1.1 General Atomics RQ‐1A Predator.

(Photo: USAF Museum).

The aeronautical configuration of a UAV is closely related to its operational mission requirements and dictated by airspeed, endurance and operational range. Whether the vehicle is fixed‐wing or rotary‐wing is determined by the speed requirements. HALE surveillance aircraft necessitate a high aspect ratio (AR) wing for flight at high altitude. In contrast, Unmanned Combat Air Vehicles (UCAVs) operate at high airspeed and perform rapid manoeuvers and therefore have low AR wings. Civilian or military applications that involve operation from off‐board a ship benefit from vertical take‐off and landing capability of the aircraft. Fixed‐wing configurations include tailplane aft, tailplane forward or canard, and tailless types.

The conventional tailplane aft designs usually have the horizontal stabiliser positioned aft on the fuselage or connected to the wings by booms. The aircraft’s centre of gravity (CG) is often forward of the aerodynamic centre (AC), which creates a nose‐down pitching moment. To this negative moment must be added the nose‐down moment characteristic of cambered wings. The net nose‐down moment is balanced by a down‐load on the tailplane.

In a canard configuration, both the foreplane and the CG are located forward of the wing. Equilibrium in pitch is achieved by the positive lift generated by the foreplane. The canard design is aerodynamically more efficient than the tailplane aft design, as both the horizontal stabiliser and the wing produce positive lift.

Tailless types include the flying wing and delta configurations. Tailless types have sweptback wings and an effective tail. The airfoils at the wingtips are set at a lower incidence than the airfoils of the inner wing, in a washout configuration to provide stability in pitch. The absence of a horizontal stabiliser reduces profile drag. However, wing sweepback in the flying wing leads to poor lift distribution, high induced drag and negative lift at high airspeeds. Delta wings have a low AR, poor lift distribution and higher induced drag caused by high span loading.

In the majority of UAVs, the powerplant is mounted at the rear of the fuselage. This arrangement makes the front of the aircraft available for the installation of a payload and allows an unobstructed view forward. There are also aerodynamic advantages when using a rear‐mounted propeller. The friction drag induced by the slipstream ahead of the pusher propeller is less than the drag generated by a front‐mounted tractor propeller. Ubiquitous types of rotary‐wing UAVs are the single‐main rotor and quad rotor (Figure 1.2). Other alternatives in design are the co‐axial rotor and hybrid configurations such as the tilt‐rotor and tilt‐wing.

Figure 1.2 Aeryon Scout VTOL MAV with gyro‐stabilized camera payload.

Photo: Dkroetsch CC‐BY‐3.0.

1.1.2 Theoretical Aerodynamics

Aerodynamic analysis of novel concepts in UAV design can be conducted using a number of methodologies that range from traditional aerodynamic theories to modern computational fluid dynamics (CFD). Thin‐airfoil theory is an analytical method that predicts lift as a function of angle of attack and assumes idealised incompressible inviscid flow. The theory can be applied to airfoils of thickness no greater than 12% of the chord (c) at low angles of attack (below the stall). Thin‐airfoil theory was developed by German–American mathematician Max Munk and further refined by British aerodynamicist Hermann Glauert in the 1920s. The theory provides a sound theoretical foundation for modern aerodynamic theories. Prandtl’s lifting‐line theory is a mathematical model for the prediction of the lift distribution along the span of a three‐dimensional wing (Figure 1.3). In the model, the vortex strength varies elliptically along the wingspan and the loss in vortex strength is shed as a vortex‐sheet from the trailing edge. Lift distribution is obtained from the wing geometry (constituent airfoil, taper, twist) and freestream conditions; that is, air density and flow velocity. Modified versions of the classical lifting‐line theory are used to compute the lift distribution in geometrically‐ or aerodynamically‐twisted wings.

Figure 1.3 Prandtl’s classical lifting‐line theory. L′, lift per unit span; ρ∞ , air density; V ∞, freestream velocity; Γ(y), circulation; Di , induced drag.

The vortex panel method is a numerical method that permits the computation of airfoil lift assuming ideal flow in which the effects of compressibility and viscosity are negligible. In this method, the shape of the airfoil surface is reconstructed using a series of vortex panels or line segments arranged to form a closed polygon. Vortex sheets mimic the boundary layer around the airfoil. The vortex sheets represent miniature vortices that give rise to circulation, hence lift.

1.1.3 Flight Regimes and Reynolds Number

The Reynolds number (Re) is a dimensionless number that indicates the ratio of inertial forces to viscous forces for given flow conditions. The concept is named after Osborne Reynolds who introduced its use in 1883. The Re characterizes different flow regimes. Laminar flow occurs at low Res, where viscous forces dominate. Turbulent flow occurs at high Res where inertial forces predominate. Small UAVs operate in the Re regime between 3 × 104 and 5 × 105. For operation at low Re, the design of efficient airfoils is critical. At 3 × 104 ≤ Re ≤ 7 × 104, relatively thick airfoils (≥6% thickness) can experience considerable hysteresis as a result of the lift and drag forces caused by laminar separation and transition to turbulent flow. Below Re values of 5 × 104, laminar separation occurs and the flow does not transition and it does not reattach to the airfoil surface. At 7 × 104 ≤ Re ≤ 2 × 105, extensive laminar flow over the surfaces of the airfoil can be attained, which reduces airfoil drag. However, in some airfoils a laminar separation bubble forms in this flight regime. At Re values above 2 × 105, airfoils become more efficient. The bubble is shorter and parasite drag decreases. The flight regime of large UAVs is in the region of Re ≥ 3 × 106. At high Re values, the laminar boundary layer transitions to turbulent a short distance downstream of the wing’s leading edge. Laminar separation and separation bubbles do not occur.

1.1.4 Airfoils for UAVs

The cost of operation of a UAV can be reduced with airfoil optimization and improvements in the vehicle’s aerodynamic efficiency. Considerations when selecting an airfoil for a UAV include a high maximum lift coefficient (c lmax), high lift‐to‐drag ratio (cl /c d), high endurance factor (c l 3/2/c d), effectiveness at low Re values, low pitching moment coefficient to minimize the load on the tail, mild stall characteristics, insensitivity to surface roughness caused by rain or dust, good flap performance, and minimal airfoil complexity for ease of manufacture. Airfoils originally designed for operation at high Re for manned aircraft (3 × 106 ≤ Re ≤ 6 × 106) are often adapted for UAVs that operate in the low‐Re flight regime (e.g., 5 × 105 ≤ Re ≤ 1.5 × 106). The...

Produkt-Details

• Erscheint lt. Verlag: 27.4.2017
• Reihe/Serie: Aerospace Series
• Reihe/Serie: Aerospace Series (PEP)
• Reihe/Serie: Aerospace Series (PEP)
• Mitarbeit: Herausgeber (Serie): Peter Belobaba, Jonathan Cooper, Allan Seabridge
• Sprache: englisch
• Themenwelt: Technik ► Fahrzeugbau / Schiffbau
• Themenwelt: Technik ► Luft- / Raumfahrttechnik
• Themenwelt: Technik ► Maschinenbau
• Schlagworte: aerodynamics • Aerodynamik • Aeronautic & Aerospace Engineering • Aero-servo-elasticity • Control • Electrical & Electronics Engineering • Elektrotechnik u. Elektronik • Gust alleviation • Luft- u. Raumfahrttechnik • Maschinenbau • Maschinenbau - Entwurf • mechanical engineering • Mechanical Engineering - Design • Optimization • quadrotor • Rotor blade • spacecraft • Systems Engineering & Management • Systemtechnik • Systemtechnik u. -management • UAV • unmanned
• ISBN-10: 1-118-92870-9 / 1118928709
• ISBN-13: 978-1-118-92870-7 / 9781118928707