Dynamic Soaring UAV Gliders Item Type text; Electronic Dissertation Authors Koessler, Jeffrey H. Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 07/10/2021 13:32:45 Link to Item http://hdl.handle.net/10150/627980 DYNAMIC SOARING UAV GLIDERS by Jeffrey H. Koessler __________________________ Copyright © Jeffrey H. Koessler 2018 A Dissertation Submitted to the Faculty of the DEPARTMENT OF AEROSPACE & MECHANICAL ENGINEERING In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY WITH A MAJOR IN AEROSPACE ENGINEERING In the Graduate College THE UNIVERSITY OF ARIZONA 2018 THEUNIVERSITY OF ARIZONA GRADUATE COLLEGE Date: 01 May 2018 RIZONA 2 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of the requirements for an advanced degree at the University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that an accurate acknowledgement of the source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the copyright holder. SIGNED: Jeffrey H. Koessler 3 Acknowledgments This network of mentors, colleagues, friends, and family is simply amazing! Many thanks to... ...My advisor Prof. Fasel for enduring my arguments and crazy ideas about the dynamics of soaring. ...My committee members for time investment, positive feedback, and most of all: encouragement. ...The University of Arizona and AME department for a dynamic environment of discovery. ...Prof. Sanfelice for turning fireflies into synchronizing oscillators and pointing me to dynamic soaring. ...Prof. Gross for my first flight in real glider, acceleration pushing me down, and my lunch almost up. ...Quinton H, Andrew D, and Bear V for believing in me 10 years ago with letters of recommendation. ...Jini K and Janae G for keeping me progressing on track and through all the administrative hoops. ...My 21 students during 4 years of Senior Design soaring projects, and Nik K for “Go big or go home”. ...The Hybrid Dynamics & Controls Lab group: Malladi B, Sean A, Yuchun L, Jun C, Alex J, Pablo N, and Ryan J for teamwork and lively arguments over a multitude of projects, exams, and problem sets. ...Malladi B for getting us past written & oral quals through countless hours of practice exam sessions. ...Brian H for our 2 AM phone calls on HW sets and projects while our growing families slept unawares. ...Chad R, Alex J, and Chris L for collaborating on projects that really made lasting impressions on me. ...Co-workers Stephen W, Neal C, Tim M, Chris M, Chris W, Drew W, Jason F, Cody M, Cody T, Jon O, Paul M, Jake E , Mike T... and many others for enduring my countless persistent questions, comments, and interruptions... in particular Stephen, fate placing his office near mine, for bearing the brunt of it. ...Marc W for his excellent, and simultaneous, driving and videoing skills during daring flight launches. ...My parents and siblings for continually believing that after every milestone, something better is ahead. ...Our three kids for believing in their dad, and left to wonder what a normal family must be like. ...My dearest Stephanie for countless hours missed while on projects, test flights, research, and deadlines. ...Last but not in the least- Thanks to all the pillars and researchers of dynamic soaring, and now potential collaborators. Acknowledging the contributions of the past- and looking towards a dynamic future! ~ ~ many thanks to all of you ~ ~ 4 To Trevor, Annika, and Gordon- our dear children who have tolerated a silly dad- Whatever paths your futures hold: life is a journey, with a destination. To all my family who have given unending support and encouragement to press on- I couldn’t have done it without you- thanks for the boundless provisions. To Stephanie- for allowing this crazy idea to be born 10 years ago, and seeing it through to fruition- I can’t wait for our next chapter in life to begin! “My life is in the Master’s hands to purify and mould; When tested, tried, I’m satisfied I shall come forth as gold!” 5 Table of Contents List of Figures 11 Abstract 15 Nomenclature 16 Chapter 1: Introduction to Dynamic Soaring 17 Chapter Introduction 17 Historical Perspective 17 Static Soaring 20 Dynamic Soaring 24 Flight Experiments 27 Motivation and Novel Contributions 31 Chapter 2: Dynamic Soaring Framework 33 Chapter Introduction 33 Aerodynamic Models 33 Wind Gradient Models 35 Dynamic Soaring Equations of Motion 40 6 Dynamic Soaring Energy 42 Chapter 3: Using Airspeed for Kinetic Energy 44 Chapter Introduction 44 Heuristic Assumptions Summary 44 HA1- A universal inertial reference does not exist- terrestrial earth is not uniquely “inertial” 45 HA2- An infinite choice of reference frames for EoM analyses and simulations are valid 46 HA3- Appropriate choice of KE velocity reference applies to aircraft flying in all conditions 47 HA4- By definition Lift cannot influence airspeed, Drag always opposes airspeed 50 HA5- Aircraft cannot distinguish between locally equivalent spatial and temporal gradients 52 HA6- KE computed from airspeed in a wind-fixed reference frame yields useful energy 54 HA7- Velocity gradients are responsible for useful energy gain in DS, not downwind turns 56 Consequences of Reference Frame Choice 57 7 C1- Source of Dynamic Soaring Energy 58 C2- Roles of Lift and Drag Forces in Energy Rates 58 C3- Exchange Between Potential Energy and Kinetic Energy Forms 59 C4- Kinetic Energy Rates as Used in Flight Control Algorithms 60 Conclusion 60 Chapter 4: Steady State Analysis 62 Chapter Introduction 62 Definition of Steady State Dynamic Soaring in an Airspeed Reference Context 62 Modeling Assumptions 63 Case 1: Steady State Descent in No Wind 64 Case 2: Steady State Descent in a Horizontal Linear Gradient of Horizontal Wind 66 Case 3: Steady State Assent in a Vertical Linear Gradient of Horizontal Wind 68 Case 4: Steady State Descent in a Vertical Linear Gradient of Horizontal Wind 71 8 Case 5: Steady State Flight in Uniform Accelerating Wind 71 Equivalence in Dynamic Soaring Scenarios 73 Dynamic Soaring Sink Polar Surface 73 Chapter 5: Reverse Kinematics Simulation 75 Chapter Introduction 75 Dynamic Soaring Framework Review 75 Typical Dynamic Soaring Simulations 77 Overview of Reverse Kinematics Simulation 79 Three-Dimensional Trajectory Formulation 80 Reverse Kinematics Algorithm 81 Example: Inclined Circular Trajectory 83 Conclusion 86 Chapter 6: Conclusions and Future Research 88 Chapter Introduction 88 Summary of Novel Contributions 89 Future Research and Applications 90 9 Appendix A: Dynamic Soaring Reference Frame 92 References 99 10 List of Figures Figure 1.1: Thermal and orographic lift 17 Figure 1.2: Rayleigh cycle for dynamic soaring 18 Figure 1.3: L-23 Super Blanik with NASA SENIOR ShWOOPIN team 19 Figure 1.4: 2008 Montague Cross Country Challenge teams 20 Figure 1.5: Typical tandem glider 21 Figure 1.6: SBXC glider sink polar 21 Figure 1.7: Sources of thermal lift 22 Figure 1.8: Sources of ridge lift 23 Figure 1.9: Sources of wave lift 23 Figure 1.10: Boundary layer wind profile 24 Figure 1.11: Albatross flight trajectory in boundary layer wind gradient 25 Figure 1.12: Circular hover 26 Figure 1.13: Snaking hover 26 Figure 1.14: Circular zoom 26 Figure 1.15: Circumnavigation 26 Figure 1.16: Valenta Weasel 2.1 m glider 28 11 Figure 1.17: Valenta Sharon 4.2 m glider 28 Figure 1.18: UAV architecture block diagram 29 Figure 1.19: Autopilot, sensors, telemetry, and control 29 Figure 1.20: Typical screenshot of mission planner GCS real-time telemetry 30 Figure 1.21: Arizona winds aloft 30 Figure 1.22: Prediction for ideal dynamic soaring conditions at test site 30 Figure 1.23: Sharon 4.2 m UAV glider 32 Figure 2.1: Air relative velocity and applied forces 34 Figure 2.2: Circular flow 38 Figure 2.3: Boundary layer wind profile 39 Figure 2.4: Horizontal wind speed vs. height 39 Figure 2.5: Horizontal wind gradient vs. height 39 Figure 2.6: Dynamic soaring forces 40 Figure 3.1: Air-relative velocity and applied forces 46 Figure 3.2: Four forces in flight 50 Figure 3.3: Dynamic soaring forces 53 12 Figure 4.1: Dynamic soaring forces 63 Figure 4.2a: Linear horizontal gradient (source) 66 Figure 4.2b: Linear horizontal gradient (sink) 66 Figure 4.2c: Radial horizontal gradient (source) 66 Figure 4.2d: Radial horizontal gradient (sink) 66 Figure 4.3: Vertical linear gradient of horizontal wind 68 Figure 4.4: Sink polar shift for heavier weight 70 Figure 4.5: Dynamic soaring sink polar surface 74 Figure 5.1: Air relative velocity and applied forces 76 Figure 5.2: Wind velocity vs height 78 Figure 5.3: Wind gradient vs height 78 Figure 5.4: Inclined circular trajectory 84 Figure 5.5: Bank angle vs trajectory position parameter for inclined circular trajectory 85 Figure 5.6: Specific energy vs trajectory position parameter for inclined circular trajectory 85 13 Figure 5.7: Load factor vs trajectory position parameter for inclined circular trajectory 86 Figure A.1: Glider descending in calm wind 92 Figure A.2: Glider ascending through accelerating wind-fixed reference frame 93 Figure A.3: Glider ascending through accelerating wind-fixed reference frame with addition of rotated DS reference frame notation (red) 94 Figure A.4: Glider descending in rotated DS reference frame 95 Figure A.5: Glider descending in simplified rotated DS reference frame 96 14 ABSTRACT Dynamic soaring in the atmospheric boundary layer of a vertical variation of horizontal winds over arbitrary terrain offers small unmanned aerial vehicle gliders the ability to greatly expand mission operations while also extending endurance.