University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Computer Science and Engineering: Theses, Computer Science and Engineering, Department of Dissertations, and Student Research Spring 4-24-2014 Autonomous Aerial Water Sampling John-Paul W. Ore University of Nebraska-Lincoln, [email protected] Follow this and additional works at:http://digitalcommons.unl.edu/computerscidiss Part of theComputer and Systems Architecture Commons, and theRobotics Commons Ore, John-Paul W., "Autonomous Aerial Water Sampling" (2014).Computer Science and Engineering: Theses, Dissertations, and Student Research. 71. http://digitalcommons.unl.edu/computerscidiss/71 This Article is brought to you for free and open access by the Computer Science and Engineering, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Computer Science and Engineering: Theses, Dissertations, and Student Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. AUTONOMOUS AERIAL WATER SAMPLING by John-Paul W. C. Ore A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfilment of Requirements For the Degree of Master of Science Major: Computer Science Under the Supervision of Carrick Detweiler and Matthew B. Dwyer Lincoln, Nebraska 2014 May, AUTONOMOUS AERIAL WATER SAMPLING John-Paul W. C. Ore, M.S. 2014 University of Nebraska, Advisers: Carrick Detweiler and Matthew B. Dwyer Obtaining spatially separated, high frequency water samples from rivers and lakes is critical to enhance our understanding and effective management of fresh water resources. Inthisthesiswepresentanaerialwatersamplerandverifythesysteminfieldexperiments. The aerial water sampler has the potential to vastly increase the speed and range at which scientistsobtainwatersampleswhilereducingcostandeffort. Thewatersamplingsystem 1 2 includes: ) a mechanism to capture three 20 ml samples per mission; ) sensors and 3 algorithms for safe navigation and altitude approximation over water; and ) software components that integrate and analyze sensor data, control the vehicle, and drive the sampling mechanism. In this thesis we validate the system in the lab, characterize key sensors, and present results of outdoor experiments. We compare water samples from locallakesobtainedbyoursystemtosamplesobtainedbytraditionalsamplingtechniques. We find that nearly all water properties are consistent between the two techniques. These experiments show that despite the challenges associated with flying precisely over water, it is possible to quickly obtain water samples with an Unmanned Aerial Vehicle (UAV). iii COPYRIGHT 2014 © , John-Paul W. C. Ore iv DEDICATION To Charles William and Constance Louise, my parents. To my ancestors Ray and Hilda, Hans and Agnes. To my sisters and their families: Heidi, Jon, Janna, Todd, Zoie, Kira, Fiona, and Ursula. v ACKNOWLEDGMENTS IwouldliketothankourlimnologistandenvironmentalengineeringpartnersDr. Michael Hamilton, Dr. Amy Burgin, and Dr. Sally Thompson, for their continuous support of these efforts. Deep thanks and gratitude to Dr. Sebastian Elbaum for his insightful suggestions and encouragement and Dr. Witawas Srisa-an for his helpful feedback. I would also like to acknowledge the valued assistance of Baoliang Zhao, Hengle Jiang, Jacob Greenwood, Adam Taylor, Dave Anthony, Jared Ostdiek, Christa Webber, Emily Waring, Dr. Seth McNeil, and the NIMBUS Lab. vi GRANT INFORMATION 2013 67021 20947 9550 ThisworkwaspartiallysupportedbyUSDA-NIAF# - - ,AFOSR#FA - 10 1 0406 1116221 - - , NSF IIS- . Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of these agencies. vii Contents Contents vii List of Figures xi List of Tables xiv 1 Introduction 1 11 3 . Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6 . Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 7 . Thesis Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Related Work 8 21 8 . Water Sampling Vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 11 . Control Systems and System States . . . . . . . . . . . . . . . . . . . . . . . . 23 11 . Information-based Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . 24 12 . Altitude Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 13 . Cable Suspended Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 13 . Water Landing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 14 . Kalman Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 15 . Low-Altitude with Human Experts . . . . . . . . . . . . . . . . . . . . . . . . viii 29 15 . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 UAV Water Sampling Applications 17 31 18 . Basic Science: Limnology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 19 . Environmental Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 20 . Disaster Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 22 . eDNA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 23 . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Electromechanical Design 24 41 24 . Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 26 . Aerial Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 29 . Design of the UAV Water Sampling Mechanism . . . . . . . . . . . . . . . . 431 30 . . Frame to hold components: the ‘Chassis’ . . . . . . . . . . . . . . . . 432 31 . . Glass Vials and Lids . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433 32 . . Servo to direct flow of water: the ‘Needle’ . . . . . . . . . . . . . . . 434 33 . . Flexible Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435 33 . . Submersible Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436 35 . . Flushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437 35 . . Breakaway Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438 36 . . Tether for Passive Safety . . . . . . . . . . . . . . . . . . . . . . . . . . 439 36 . . Embedded System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 39 . Sensors For Near Water Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . 441 39 . . Ultrasonic Rangefinders . . . . . . . . . . . . . . . . . . . . . . . . . . 442 42 . . Water Conductivity Sensors . . . . . . . . . . . . . . . . . . . . . . . . 45 43 . Electro-Mechanical Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . ix 5 Software 44 51 . Ground Station Software: 46 Mission Control, State Machine, Safety Monitor . . . . . . . . . . . . . . . . 511 46 . . General UAV Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512 47 . . Water Sampling Specific Code . . . . . . . . . . . . . . . . . . . . . . 513 48 . . Finite State Automata (FSA) . . . . . . . . . . . . . . . . . . . . . . . . 52 50 . Embedded Software: Pumping, Flushing, and Sensing . . . . . . . . . . . . 53 53 . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Altitude Estimation and Water Sampling Effectiveness 54 61 55 . Altitude Estimation Over Water . . . . . . . . . . . . . . . . . . . . . . . . . . 611 56 . . Characterization of Pressure Sensors . . . . . . . . . . . . . . . . . . . 612 59 . . Characterization of Ultrasonic Rangefinders . . . . . . . . . . . . . . 613 62 . . Kalman Filter Low-Altitude Estimation . . . . . . . . . . . . . . . . . 614 67 . . Final Altitude Estimate . . . . . . . . . . . . . . . . . . . . . . . . . . 62 69 . Sampler Effectiveness Experiments - Indoor . . . . . . . . . . . . . . . . . . . 63 70 . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Field Experiments 71 71 72 . Outdoor Altitude Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 73 . Outdoor Water Sampling Effectiveness . . . . . . . . . . . . . . . . . . . . . . 73 75 . Water crash at Holmes Lake, Lincoln NE . . . . . . . . . . . . . . . . . . . . 74 76 . Demonstration at Blue Oak Ranch Reserve . . . . . . . . . . . . . . . . . . . 75 77 . Water Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 751 79 . . Dissolved Oxygen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752 81 . . Dissolved Gasses: Sulfate and Chloride . . . . . . . . . . . . . . . . .