Springer Aerospace Technology

Flight Systemsand Control

Tian Seng Ng

A Practical Approach

Springer Aerospace Technology

The Springer Aerospace Technology series is devoted to the technology of aircraftand spacecraft including design, construction, control and the science. The bookspresent the fundamentals and applications in all fields related to aerospaceengineering. The topics include aircraft, missiles, space vehicles, aircraft engines,propulsion units and related subjects.

More information about this series at http://www.springer.com/series/8613

Tian Seng Ng

Flight Systems and ControlA Practical Approach

123

Tian Seng NgNanyang Technological University Schoolof Mechanical and Aerospace Engineering

SingaporeSingapore

ISSN 1869-1730 ISSN 1869-1749 (electronic)Springer Aerospace TechnologyISBN 978-981-10-8720-2 ISBN 978-981-10-8721-9 (eBook)https://doi.org/10.1007/978-981-10-8721-9

Library of Congress Control Number: 2018935953

© Springer Nature Singapore Pte Ltd. 2018, corrected publication 2020This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or partof the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations,recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmissionor information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilarmethodology now known or hereafter developed.The use of general descriptive names, registered names, trademarks, service marks, etc. in thispublication does not imply, even in the absence of a specific statement, that such names are exempt fromthe relevant protective laws and regulations and therefore free for general use.The publisher, the authors and the editors are safe to assume that the advice and information in thisbook are believed to be true and accurate at the date of publication. Neither the publisher nor theauthors or the editors give a warranty, express or implied, with respect to the material contained herein orfor any errors or omissions that may have been made. The publisher remains neutral with regard tojurisdictional claims in published maps and institutional affiliations.

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In Memory ofThe LateAssoc. Prof. Dr. Ng Wan Sing

Preface

Aviation technology has been in existence since the last century. Throughout thedecades, many developments have evolved in flight mechanics and control inaerospace engineering. Especially, nowadays, where computers are becoming morepopular, technological control has progressed to combine with computed technol-ogy for automated and more precise methods of control. Software control can takethe place of hardwired control system economically. Hence, new control tech-nologies are progressively discovered and taught in institutions.

Many research and studies over the years have found significant improvementsin the development of the aerospace technology. The results are the establishmentsof the unmanned flying vehicles and the micro air vehicles. Flight instruments andsensors are parts and parcels in the aerospace control system. Since we consideredweights a crucial factor to the UAV airplane systems, we can reduce payloads bythe replacements of integrated software functions for aviation equipment. Besideshaving the advanced composite materials used in aerospace structure to improve theaerodynamics of the aircraft, studies have been ongoing in the power control offlight vehicles. Recent developments have made through to the solar power controlUAVs and research in the vertical takeoff and landing (VTOL) technology.

Modern technology in aviation has brought us to the present developments inflight control systems and progressing toward the millenniums. Future transporta-tion will depend heavily on the research investment in the domain of aerospacetechnology. Fundamentals of aerospace control techniques apply to various flightcontrol systems. Its applications range from the fixed-wing aircraft to the movingblades rotor helicopter system. More advanced air structures like the UAVs, MAVs,quadrotors, etc., implement the same control technology. Furthermore, precisesensors’ feedbacks are responsible for the survival of the flying air vehicles. As canbe seen, flight control engineering has made a critical impact on the aerospaceindustrials.

vii

The book starts with the basics of flight mechanics and navigational modulesnecessary for the flight control system. Illustrative diagrams and graphical pro-gramming examples narrate the details of the sensor function design. It also pre-sents the modern developments in unmanned flight systems. Readers can find thevarious flight computer control and its accessories for flight engineering practicesand applications.

Singapore, Singapore Tian Seng NgJanuary 2018

viii Preface

Acknowledgements

The author would like to express his sincere gratitude to Associate Professor GoTiauw Hiong, Assistant Professor Son Hungsun, Assistant Professor Naba Peyada,and Dr. Omar Kasim Ariff in leading the many different UAV projects’ teams and fortheir expertise and guidance on the flight dynamics and control topics. Nice to workwith the member of academic staff Dr. Narayanaswamy Nagarajan on the experi-mental setup of the navigational components. Thanks to the research associateMr. You Youngil for some of the pictorial information in Chap. 6. Also thanks to theAssistant Professor Erdal Kayacan, Assistant Professor Ng Bing Feng, AssistantProfessor Chan Wai Lee, and the Adjunct Professor Lim Yeow Khee who teach inthe aerospace division. The solar UAV team leaders Associate Professor Ng HeongWah and Assistant Professor Li Peifeng with their members, Koh JiaJian, Alvin YeoMeng Teck, and Cheong Wen Rong. The undergraduates Lee Ying Qin, SukhdevSingh, Teng Yeow Hwee, and Benidict Low Zhi Wei for their parts in fuel cells andlong endurance flight. Yue Sai Kei, Lee Kee Jin, Calvin Lin Shenghuai, Koe HanBeng, Jayawijayaningtiyas, and Rudy Ryantone Setiawan for the Night Raven UAVdesign. In addition, the author would like to thank Ms. Dong Yu for providing theLabVIEW solutions to the IMU components. Besides, the author is also grateful toMr. Muhammad Hamka Ibrahim, the support engineer, for attending to theLabVIEW software enquiries. The support team including Mr. Ow Yong See Meng,Mr. Sa’Don Bin Ahmad, Mrs. Low-Chia Hwee Lang, Mr. Lam Kim Kheong,Mr. Seet Thian Beng, Mr. Ting Li Yong, Mr. Cheo Hock Leong, Mr. Lim YongSeng, Mr. Tan Boon Hwee, Mr. Chua Chor Lee, Mr. Mazlan, and Mr. Ang Hanlin inthe engineering laboratory. Last but not least, the researchers Andriy Sarabakha, EfeCamci, Mohit Mehndiratta, Yunus Govdeli, Nursultan Imanberdiyev, Wong ZhuoWei, Ravindrababu Suraj, Dogan Kircali, and Siddharth Patel who have supportedthe laboratory. Appreciations to my family members and friends for their overallsupport and patience. Without these people, the writing of the book would not havebeen a success. Finally, I would like to thank NTU, school of MAE, Division ofAerospace Engineering, for giving me the opportunity to make the work a reality.

ix

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Preliminary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Book Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Chapters’ Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 Flight Mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1 Basic Flight System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.2 Steady Straight Level Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.3 Takeoff Maneuver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.4 Glider Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.5 Aircraft Failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 Navigational Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.1 Magnetic Heading Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.2 Acceleration Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.3 Global Positioning System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.3.1 GPS Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333.4 Integrated Navigational System . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4 Flight Simulator Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434.1 Flight Software and Yoke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434.2 Aircraft C-130 Simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464.3 Flight Determination of Aircraft Performance . . . . . . . . . . . . . . . . 484.4 Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

5 Tandem Rotor Helicopter Control . . . . . . . . . . . . . . . . . . . . . . . . . . 555.1 Fundamentals of Control System . . . . . . . . . . . . . . . . . . . . . . . . . 555.2 Tandem Rotor Modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595.3 PID Control Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

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5.4 Elevation Control Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655.4.1 Elevation Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655.4.2 Elevation Controllers Design . . . . . . . . . . . . . . . . . . . . . . 77

5.5 Elevation Disturbance Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 825.6 Pitch Control Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

5.6.1 Pitch Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865.6.2 Pitch Controllers Design . . . . . . . . . . . . . . . . . . . . . . . . . 87

5.7 Travel Control Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885.7.1 Travel Position Control . . . . . . . . . . . . . . . . . . . . . . . . . . 885.7.2 Travel Position Controller Design . . . . . . . . . . . . . . . . . . . 89

5.8 Travel Rate Control Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 915.8.1 Travel Rate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 915.8.2 Travel Rate Controller Design . . . . . . . . . . . . . . . . . . . . . 92

5.9 3-DOF Helicopter Control System . . . . . . . . . . . . . . . . . . . . . . . . 955.10 Real Time Control Implementation . . . . . . . . . . . . . . . . . . . . . . . 98

6 Unmanned Aerial Vehicle System . . . . . . . . . . . . . . . . . . . . . . . . . . . 1096.1 Autopilots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1096.2 Machine Vision Payload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116.3 Telemetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1146.4 Ground Control Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1166.5 Unmanned Wooden Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

7 Rotorcrafts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1197.1 Quadrotor Modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

7.1.1 Hovering Body Parallel to the Ground . . . . . . . . . . . . . . . 1197.1.2 Altitude Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

7.2 State-Space Control Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1217.3 Attitude LQR Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1257.4 Attitude Control Result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1267.5 Control of the Quadcopter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1277.6 LQR Control Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

7.6.1 Controllability and Observability . . . . . . . . . . . . . . . . . . . 1307.6.2 Modified LQR Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 1337.6.3 The Threshold Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.7 Quadcopter Computations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1387.8 Multiple Quadcopters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

8 Flight Instrumentation Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . 1558.1 Inertial Navigation Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1558.2 INS Hardware Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1568.3 Sensor Information Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . 157

xii Contents

8.4 GUI Software Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1628.4.1 Internal Computation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1628.4.2 Main Function Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1628.4.3 Input Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

8.5 Robotic Navigational Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1688.5.1 Packet Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1728.5.2 GPS Receiving Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

8.6 IMU Data Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1838.7 IMU 3D Model Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

8.7.1 VRML Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1908.7.2 IMU Model Attitude Control . . . . . . . . . . . . . . . . . . . . . . 193

9 Recent and Future Developments . . . . . . . . . . . . . . . . . . . . . . . . . . . 1999.1 Solar UAV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

9.1.1 Solar-Powered Methodology . . . . . . . . . . . . . . . . . . . . . . . 2009.1.2 Wind Tunnel Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2019.1.3 Flight System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2029.1.4 Long Endurance UAV Flight . . . . . . . . . . . . . . . . . . . . . . 203

9.2 Wind-Powered Energy Source . . . . . . . . . . . . . . . . . . . . . . . . . . . 2039.3 Fuel Cell Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2059.4 Vertical Takeoff/Landing Air Vehicles . . . . . . . . . . . . . . . . . . . . . 2079.5 New Stealth Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2109.6 Aerial Systems Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

. . . . . . . . . . . . . . . . . . . . . .

Appendix A: LabVIEW Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Appendix B: Tricopter Graphical Programming . . . . . . . . . . . . . . . . . . . 227

Appendix C: Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

Contents xiii

C1Correction to: Flight Systems and Control

List of Figures

Fig. 2.1 Cessna instrument panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Fig. 2.2 Learjet instrument panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Fig. 2.3 Cessna airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Fig. 2.4 Learjet airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Fig. 2.5 Four forces of flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Fig. 2.6 Force equilibrium in steady straight level flight . . . . . . . . . . . . . 5Fig. 2.7 Assumed force equilibrium in steady straight level flight . . . . . . 6Fig. 2.8 Forces acting on the aircraft during takeoff. . . . . . . . . . . . . . . . . 8Fig. 2.9 Styrofoam glider set (a–f). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Fig. 3.1 Typical aircraft navigation system . . . . . . . . . . . . . . . . . . . . . . . 14Fig. 3.2 Earth magnetic pole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Fig. 3.3 Magnetic dipole [3] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Fig. 3.4 Inclination and declination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Fig. 3.5 Magnetic field signals’ amplifications . . . . . . . . . . . . . . . . . . . . . 15Fig. 3.6 Magnetic sensorcircuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Fig. 3.7 Magnetic sensor experimental circuit . . . . . . . . . . . . . . . . . . . . . 17Fig. 3.8 Magnetic field components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Fig. 3.9 Scaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Fig. 3.10 Y data analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Fig. 3.11 Acceleration example (a–c). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Fig. 3.12 Accelerometer circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Fig. 3.13 Angular motion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Fig. 3.14 Duty cycle (T1/T2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Fig. 3.15 Accelerometer experiment set . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Fig. 3.16 Two axes acceleration plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Fig. 3.17 Phase shift versus rotating angles . . . . . . . . . . . . . . . . . . . . . . . . 26Fig. 3.18 Earth satellites constellation [7] . . . . . . . . . . . . . . . . . . . . . . . . . 29Fig. 3.19 Satellite signal transmissions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Fig. 3.20 Garmin GPS receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Fig. 3.21 Pseudo ranging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Fig. 3.22 Satellites’ measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

xv

Fig. 3.23 Geometric dilution of precision. . . . . . . . . . . . . . . . . . . . . . . . . . 31Fig. 3.24 RF signal modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Fig. 3.25 Conceptual system diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Fig. 3.26 GPS satellites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Fig. 3.27 GPS simulator experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Fig. 3.28 GPS simulator panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Fig. 3.29 Satellite information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Fig. 3.30 NMEA messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Fig. 3.31 WinPlot GPS software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Fig. 4.1 Flight simulator software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Fig. 4.2 Flight sim yoke. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Fig. 4.3 Flight instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Fig. 4.4 Simulator yoke functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Fig. 4.5 Flight simulator C-130 Platform (a–d) . . . . . . . . . . . . . . . . . . . . 47Fig. 4.6 Hydraulic components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48Fig. 4.7 Angular velocity diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Fig. 4.8 Pitot-tube based airspeed indicator . . . . . . . . . . . . . . . . . . . . . . . 50Fig. 4.9 Drag polar for Cessna U3A [13]. . . . . . . . . . . . . . . . . . . . . . . . . 51Fig. 4.10 Plot of CD versus C2

L for Cessna U3A [13] . . . . . . . . . . . . . . . . 52Fig. 4.11 C-130 aircraft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Fig. 5.1 System setup (credit Quanser Inc.) . . . . . . . . . . . . . . . . . . . . . . . 56Fig. 5.2 Laplace transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56Fig. 5.3 Mathematical model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Fig. 5.4 Two phases of a signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Fig. 5.5 System response characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 58Fig. 5.6 Feedback control block diagram . . . . . . . . . . . . . . . . . . . . . . . . . 59Fig. 5.7 Chinook helicopter representative (credit Quanser Inc.) . . . . . . . 60Fig. 5.8 Elevation axis diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Fig. 5.9 Pitch axis diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61Fig. 5.10 Travel axis diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62Fig. 5.11 PID control structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Fig. 5.12 Open loop elevation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Fig. 5.13 Proportional elevation diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 65Fig. 5.14 Output evaluation (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Fig. 5.15 PD elevation diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Fig. 5.16 PD elevation control (a–d) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Fig. 5.17 Alternative PD elevation diagram . . . . . . . . . . . . . . . . . . . . . . . . 68Fig. 5.18 Alternative PD elevation control (a–d) . . . . . . . . . . . . . . . . . . . . 69Fig. 5.19 PI elevation diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69Fig. 5.20 PI elevation control (a–d) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70Fig. 5.21 Alternate PI elevation diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 71Fig. 5.22 Alternate PI elevation control (a–d) . . . . . . . . . . . . . . . . . . . . . . 71Fig. 5.23 PID elevation diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72Fig. 5.24 PID elevation control (a–h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

xvi List of Figures

Fig. 5.25 Alternative PID elevation diagram . . . . . . . . . . . . . . . . . . . . . . . 73Fig. 5.26 Alternative PID elevation control (a–h) . . . . . . . . . . . . . . . . . . . 74Fig. 5.27 2nd alternative PID elevation diagram . . . . . . . . . . . . . . . . . . . . 75Fig. 5.28 2nd alternative PID elevation control (a–h) . . . . . . . . . . . . . . . . 76Fig. 5.29 3rd alternative PID elevation diagram. . . . . . . . . . . . . . . . . . . . . 76Fig. 5.30 3rd alternative PID elevation control (a–h). . . . . . . . . . . . . . . . . 78Fig. 5.31 Second order elevation simulated response . . . . . . . . . . . . . . . . . 78Fig. 5.32 PD elevation simulated response. . . . . . . . . . . . . . . . . . . . . . . . . 79Fig. 5.33 PID elevation simulated response . . . . . . . . . . . . . . . . . . . . . . . . 80Fig. 5.34 Alternate PID elevation simulated response . . . . . . . . . . . . . . . . 81Fig. 5.35 Open loop elevation with disturbance . . . . . . . . . . . . . . . . . . . . . 82Fig. 5.36 Closed-loop elevation with disturbance. . . . . . . . . . . . . . . . . . . . 82Fig. 5.37 PID elevation with disturbance . . . . . . . . . . . . . . . . . . . . . . . . . . 83Fig. 5.38 PD elevation control with disturbance (a, b) . . . . . . . . . . . . . . . 84Fig. 5.39 PID elevation control with disturbance (a, b) . . . . . . . . . . . . . . . 85Fig. 5.40 Open loop pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86Fig. 5.41 Proportional pitch diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86Fig. 5.42 PD pitch diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86Fig. 5.43 PID pitch diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86Fig. 5.44 Second order pitch simulated response . . . . . . . . . . . . . . . . . . . . 88Fig. 5.45 Open loop travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88Fig. 5.46 Proportional travel diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Fig. 5.47 PD travel diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Fig. 5.48 PID travel diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Fig. 5.49 Second order travel simulated response . . . . . . . . . . . . . . . . . . . 90Fig. 5.50 PID travel simulated response (a, b). . . . . . . . . . . . . . . . . . . . . . 90Fig. 5.51 Open loop travel rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Fig. 5.52 Proportional travel rate diagram . . . . . . . . . . . . . . . . . . . . . . . . . 91Fig. 5.53 PI travel rate diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Fig. 5.54 Alternate PI travel rate diagram . . . . . . . . . . . . . . . . . . . . . . . . . 92Fig. 5.55 Proportional travel rate simulation (a, b) . . . . . . . . . . . . . . . . . . 93Fig. 5.56 PI travel rate simulation (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . 93Fig. 5.57 Alternate PI travel rate simulation (a, b). . . . . . . . . . . . . . . . . . . 93Fig. 5.58 Encoders’ directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94Fig. 5.59 Travel position control diagram . . . . . . . . . . . . . . . . . . . . . . . . . 95Fig. 5.60 Travel rate control diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95Fig. 5.61 Real time control implementation (a, b) . . . . . . . . . . . . . . . . . . . 96Fig. 5.62 Improved elevation (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99Fig. 5.63 Elevation control (a, b). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100Fig. 5.64 Control by scaling (a–d). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101Fig. 5.65 Pitch filter control (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102Fig. 5.66 Travel rate control (a–c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103Fig. 5.67 Different control gains R (a–c) . . . . . . . . . . . . . . . . . . . . . . . . . . 104Fig. 5.68 Travel axis comparisons (a–c) . . . . . . . . . . . . . . . . . . . . . . . . . . 105

List of Figures xvii

Fig. 6.1 Unmanned aerial vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110Fig. 6.2 Flapping wings MAV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110Fig. 6.3 Ardupilot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111Fig. 6.4 Micropilot and modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112Fig. 6.5 Sparkfun autopilot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112Fig. 6.6 Gimbal and accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113Fig. 6.7 Micro-air vehicle cameras . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113Fig. 6.8 OSD system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114Fig. 6.9 XBee module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115Fig. 6.10 SeaGull-Pro transmitter/receiver set . . . . . . . . . . . . . . . . . . . . . . 115Fig. 6.11 YJPro 5.8 GHz transmission set (Iftron) . . . . . . . . . . . . . . . . . . . 115Fig. 6.12 Ground control station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116Fig. 6.13 Rotomotion helicopters with heli-controller XL40 . . . . . . . . . . . 117Fig. 6.14 Wooden material constructions . . . . . . . . . . . . . . . . . . . . . . . . . . 118Fig. 6.15 UAV—Night Raven . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118Fig. 7.1 Quadcopters and controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121Fig. 7.2 Tricopter and controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122Fig. 7.3 Quadrotor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122Fig. 7.4 Rotorcraft motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122Fig. 7.5 Attitude control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127Fig. 7.6 Controller model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130Fig. 7.7 Uncontrollable states revealed. . . . . . . . . . . . . . . . . . . . . . . . . . . 133Fig. 7.8 Modified LQR simulated control rotorcraft (a, b) . . . . . . . . . . . . 136Fig. 7.9 Output without the holding voltage Ub (a, b) . . . . . . . . . . . . . . . 137Fig. 7.10 Model axes configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143Fig. 7.11 LabVIEW simulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144Fig. 7.12 Tricopter CAD model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145Fig. 7.13 Single UAV controller block diagram. . . . . . . . . . . . . . . . . . . . . 146Fig. 7.14 Quadrotor fleet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148Fig. 7.15 Multicopter control block diagram . . . . . . . . . . . . . . . . . . . . . . . 149Fig. 7.16 Multicopter simulation [17] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150Fig. 7.17 Multicopter with single rotorcraft disturbances . . . . . . . . . . . . . . 151Fig. 7.18 Fleet control with wind gust simulation . . . . . . . . . . . . . . . . . . . 152Fig. 8.1 Crossbow IMUs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156Fig. 8.2 Hardware interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158Fig. 8.3 Raw packet data (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160Fig. 8.4 IMU300CC block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161Fig. 8.5 Raw acceleration impedance circuit . . . . . . . . . . . . . . . . . . . . . . 161Fig. 8.6 Sensor data computation (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . 163Fig. 8.7 LabVIEW design block 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164Fig. 8.8 LabVIEW design block 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165Fig. 8.9 Checksum calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165Fig. 8.10 VISA configuring design block. . . . . . . . . . . . . . . . . . . . . . . . . . 166Fig. 8.11 IMU300CC GUI display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

xviii List of Figures

Fig. 8.12 GyroVIEW software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168Fig. 8.13 Data logged in voltage mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 169Fig. 8.14 MNAV100CA architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170Fig. 8.15 MICRO-VIEW software (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . 171Fig. 8.16 MNAV100CA device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175Fig. 8.17 GPS graphical solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178Fig. 8.18 Interior design (a–d) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179Fig. 8.19 Retrieve token sub VI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181Fig. 8.20 GPGGA sentence extract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182Fig. 8.21 MNAV100CA input setting (a, b) . . . . . . . . . . . . . . . . . . . . . . . 184Fig. 8.22 Inner while loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184Fig. 8.23 Checksum computation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185Fig. 8.24 Saving and displaying data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185Fig. 8.25 IMU internal VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186Fig. 8.26 Scaled mode detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187Fig. 8.27 ‘E’ entrance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188Fig. 8.28 Locating GPS data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189Fig. 8.29 GPS internal VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192Fig. 8.30 GPS information readout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192Fig. 8.31 Alternate GPS internal VI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193Fig. 8.32 IMU graphical solution [22] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194Fig. 8.33 Draw IMU model (a–c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195Fig. 8.34 IMU 3D model interface (a, b). . . . . . . . . . . . . . . . . . . . . . . . . . 197Fig. 9.1 Solar powered UAV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200Fig. 9.2 Solar energy absorbed wings . . . . . . . . . . . . . . . . . . . . . . . . . . . 201Fig. 9.3 Electronics components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201Fig. 9.4 Solar UAV wind tunnel model . . . . . . . . . . . . . . . . . . . . . . . . . . 202Fig. 9.5 Electrical configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202Fig. 9.6 Aerospace multidisciplinary areas . . . . . . . . . . . . . . . . . . . . . . . . 204Fig. 9.7 Solar plane model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204Fig. 9.8 Aerodynamic characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204Fig. 9.9 Wind-powered turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205Fig. 9.10 Aeropak fuel cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206Fig. 9.11 Airframe system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206Fig. 9.12 Thrust versus propeller characteristic . . . . . . . . . . . . . . . . . . . . . 206Fig. 9.13 VTOL MAV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207Fig. 9.14 Wing tunnel models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208Fig. 9.15 The Falcon 8+ (Credit Intel Corporation) . . . . . . . . . . . . . . . . . . 208Fig. 9.16 VTOL X-plane (Courtesy of DARPA) . . . . . . . . . . . . . . . . . . . . 209Fig. 9.17 Tilt rotor aircraft (Courtesy of Bell) . . . . . . . . . . . . . . . . . . . . . . 209Fig. 9.18 VTOL electric jet (Courtesy of Lilium) . . . . . . . . . . . . . . . . . . . 210Fig. 9.19 VTOL electric copter (Courtesy of Volocopter GmBH) . . . . . . . 210Fig. 9.20 Stealths (Courtesy of BAE Systems). . . . . . . . . . . . . . . . . . . . . . 211

List of Figures xix

List of Tables

Table 2.1 Aircraft component failures . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Table 3.1 Experimental data calculations . . . . . . . . . . . . . . . . . . . . . . . . . 22Table 3.2 Serial port configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Table 3.3 Satellites tracked positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Table 5.1 Three DOF helicopter system parameters

(credit Quanser Inc.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Table 5.2 Ziegler–Nichols tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81Table 5.3 Elevator K gains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104Table 6.1 Data packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117Table 6.2 Night Raven specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118Table 7.1 Model parameters’ specifications (Credit Quanser Inc.) . . . . . . 124Table 7.2 LQR gain K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132Table 7.3 K gain after pole placements . . . . . . . . . . . . . . . . . . . . . . . . . . 135Table 7.4 PD controller gains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140Table 8.1 IMU300CC data packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159Table 8.2 Serial port pin assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . 170Table 8.3 Command input packets (a–c) . . . . . . . . . . . . . . . . . . . . . . . . . 172Table 8.4 Output rate selection table . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173Table 8.5 Device query (a, b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173Table 8.6 MNAV100CA data packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174Table 8.7 Extended Bytes in ‘N’ data packet. . . . . . . . . . . . . . . . . . . . . . 175Table 8.8 GPS data packet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176Table 8.9 GPS data transport cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176Table 8.10 GPS NMEA sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

xxi

List of Programs

P5.1 Matlab PID Plot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81P5.2 Tandem Rotor LQR Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106P7.1 LQR With Pole Placement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135P7.2 Stability Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141P8.1 3D Model VRML Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

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Chapter 1Introduction

1.1 Preliminary

The employment of the flight computer control is very common in airplanes as weused to travel around the world in the automated aircraft system. Advances intechnological efforts have made air vehicle autonomous. Therefore, the studies andunderstandings of the scope are necessary for building automated aircraft systems.The more complex automatic systems need a thorough grasping of the related topicsin the book. The materials presented in this book explains the concept of navigationfrom the acceleration, heading or direction of the air vehicle. The electronics basedsensing components we built provides a good foundation for laboratory-basedexperimental study and practices. Besides, the book also introduced flightmechanics, simulators and flight accessories for the gliders. Excerpts of the threedegrees of freedom helicopter system can open insights to aircraft control engineers.Moreover, the readers can also appreciate the knowledge and its applications to themodern control technique for the rotorcraft system. Interesting flight instrumenta-tion and programmable control techniques can enhance the interest of the bookexplorers. We can discover up to date topics in the air vehicle automated systemand the modern technology used in controlling the air automobile system.

1.2 Book Highlights

The book presents the studies of the flight vehicles and its navigational systems. Italso analyzes the several forms of flight structures and its control systems. Softwaresimulation enables us to test the hardware without actual implementation.Moreover, we also introduced the hardware means for air vehicle navigation.Altogether, they comprised the hardware and software necessary in a flight system.

© Springer Nature Singapore Pte Ltd. 2018T. S. Ng, Flight Systems and Control, Springer Aerospace Technology,https://doi.org/10.1007/978-981-10-8721-9_1

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• The usefulness of the magnetic field finds its application in the heading sensor.• Modern satellite navigation method based on GPS is experimented in the

laboratory.• Electronic circuit for the acceleration sensor is constructed and tested.• The integration of the three sensing units comprises the flight instrumentation

system.• Applied control theory presents to design control system for the flying crafts.• MATLAB algorithm runs to simulate the helicopter control behavior before real

time implementation.• Software model of the air vehicle simulates to validate the controllers we design.• LabVIEW software interfaces to detect and read the flight navigational sensors.

The parameters feedback can then control the aircraft or flight movement andtrajectory.

1.3 Chapters’ Organization

• Chapter 2 familiarizes the basic mechanics of a flight system. Readers willexplore the effects of aircraft control surfaces and their related equations, besidesthe cockpit flight instruments.

• Chapter 3 highlights the low-cost electronic sensors for navigation. These basiccomponents serve as dead reckoning sensors for an air vehicle.

• Chapter 4 enhances the understanding of flight characteristics and their effectson flight performance with flight simulators.

• Chapter 5 studies the tandem rotor helicopter for understanding the dynamics,control and stability analysis of the flight vehicle.

• Chapter 6 introduces the basic communication and control hardware for thevarious kinds of rotorcrafts, micro-air vehicles (MAVs) and quadcopter systems.

• Chapter 7 illustrates the programming and control of a quadrotor system.LabVIEW design of the flying craft verifies our controller design for the system.

• Chapter 8 presents the integration of the flight instrumentation on the softwareenvironment for sensing the direction, acceleration, and location of the airvehicle. The developed software detects the navigation sensors.

• Chapter 9 discusses the various natural resources available as renewable energyfor the aerospace industries. It also reviews the developments of the new verticaltakeoff and landing aircraft, etc.

2 1 Introduction

Chapter 2Flight Mechanics

2.1 Basic Flight System

The study of the flight mechanics provide the fundamentals of aerospace engi-neering relating to any conventional flight vehicles. To fly and control the aircraft,we need to know the flight mechanics of the system. In an air vehicle, we have tocontrol the ailerons (roll), the elevator (pitch) and the rudder (yaw). Aerodynamicproperty such as the lift coefficient is also important to the flying vehicle. Forexample, how does the flap affects the take-off properties of the airplane?Furthermore, the power setting relates to the flying characteristics of the aircraft aswell. The flight spoilers are controllable by the pilot. We used them together withthe brake, and thruster to reduce the speed of the air vehicle, at the point of landingon the ground. The instrument panel in the cockpit of an aircraft gives the readoutof any metering of the system. It is these feedback indicators in the panel that thepilot can control the airplane to perform a smooth ride. Two types of aircraft are ofdifferent characteristics ideal for studies and comparisons. We have the singleengine propelled Skyhawk or Cessna C172SP airplane, and the two-turbofanengine, fixed wing Bombardier Learjet 45 airplane. The maximum fuel payload forthe Cessna airplane is about 154.22 kg, which is equivalent to 340 lb. The landinggear or landing pair of wheel is retractable only in the Learjet airplane system(Figs. 2.1, 2.2, 2.3 and 2.4).

2.2 Steady Straight Level Flight

The understanding of the fundamental forces in flight is critical as it affects theflight performances of the flying plane. For aircraft flying in the atmosphere, thereare mainly four forces of flight: lift (L), drag (D), thrust (T) and weight (W), asillustrated in Fig. 2.5. Lift and drag are an aerodynamics type of forces that are

© Springer Nature Singapore Pte Ltd. 2018T. S. Ng, Flight Systems and Control, Springer Aerospace Technology,https://doi.org/10.1007/978-981-10-8721-9_2

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present due to the relative motion of the aircraft with respect to the air. The thrustproduces by the propulsion system pushes the airplane forward and overcomes thedrag. Weight is present due to gravity, which is a natural force pulling the aircraftdownward. Flight characteristic of an aircraft is dependent on the interaction ofthese four forces. The standard type of flight is the so-called steady straight level

Fig. 2.1 Cessna instrument panel

Fig. 2.2 Learjet instrument panel

4 2 Flight Mechanics

Aileron Flap

Elevator

Spoiler

Rudder

Fig. 2.3 Cessna airplane

Spoiler

Flap

AileronRudder

Elevator

Fig. 2.4 Learjet airplane

Weight

Drag Thrust

Lift

Fig. 2.5 Four forces of flight

Fig. 2.6 Force equilibrium insteady straight level flight

2.2 Steady Straight Level Flight 5

flight, where the aircraft flies in a straight-line trajectory with constant airspeed andaltitude with its wings in level position. In this case (see Fig. 2.6), where the enginethrust angle aT

T cos aT ¼ D ð2:1Þ

Lþ T sin aT ¼ W ð2:2Þ

indicates the angle the thrust makes with respect to the flight direction. For con-ventional aircraft performing conventional flight, aT is often small, and thus thefollowing approximate relations applies (see Fig. 2.7)

T ¼ D ð2:3Þ

L ¼ W ð2:4Þ

These approximations have been used widely for determining an aircraft’s flyingcharacteristics. Equation (2.3) suggests that the thrust required maintaining thesteady straight level flight is equivalent to the drag experienced by the aircraft.Similarly, in steady straight level flight, the lift needed is the same as the weight ofthe aircraft at the particular instant.

Power Required:

Power (P) is defined as the time rate of change of the work done and is equivalent toforce (F) in the direction of motion times the speed (V).

P ¼ FV ð2:5Þ

The power required (PR) to maintain steady straight level flight is defined as thethrust required times the steady-state airspeed (V∞), and by Eq. (2.3), this can beexpressed as

PR ¼ DV1 ð2:6Þ

In general, the variation of the power required with airspeed and altitude is notlinear because D is both a function of air density (p∞), which varies with altitudeand airspeed (V∞) is as follow,

Fig. 2.7 Assumed forceequilibrium in steady straightlevel flight

6 2 Flight Mechanics

D ¼ 12p1 V12SCD ð2:7Þ

where S is the aircraft’s wing platform area, and CD is the aircraft’s drag coefficient.The plot of PR versus V∞ at a given altitude is usually called the power-requiredcurve. For the aircraft using a propeller engine, we usually cannot directly obtainthe power required from the reading of the instrument panel. The power producedby the propeller usually has a complex relationship with the engine RPM (revo-lution per minute), the propeller diameter, and the air density. For the case, asimplified assumption used is that the engine RPM is proportional to the powerproduced by the propeller for the flight condition used.

Thrust Required:

The thrust required (Tg) to maintain steady straight level flight is defined as thethrust required times the steady-state airspeed (V∞), and from Eq. (2.3), it can beexpressed as:

Tg ¼ D ð2:8Þ

In general, the variation of the thrust required with airspeed and altitude is notlinear, because D is both a function of air density (p∞), which varies with altitudeand airspeed. Thus, we can define

Tg ¼ 12p1V12SCD ð2:9Þ

with reference to Eq. (2.7). Where S is the aircraft’s wing platform area, and CD isthe aircraft’s drag coefficient. The relationship between Tg and V∞ at a givenaltitude is usually called the thrust required curve.

Maximum Airspeed:

Generally, for the steady straight level flight at a specific altitude in the relativelyhigh range of the aircraft, the drag increases as the airspeed increases. FromEq. (2.3), this implies that the thrust or power required in maintaining the steadystraight level flight also increases. If the airspeed is further increased, it will reach apoint where the power required is the maximum the propulsion of the aircraft cangenerate. In the situation, the airspeed for a steady straight level flight cannotincrease further. When the aircraft is in steady straight level flight with maximumpropulsion power at a specific altitude, then the steady airspeed at which the aircraftflies is the maximum airspeed for that altitude.

Coefficient of Lift:

Like drag, lift (L) is also a function of air density (p∞), which varies with altitudeand airspeed (V∞), as follows:

2.2 Steady Straight Level Flight 7