Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2015 A Reflective, 3-Dimensional Behavior Tree Approach to Vehicle Autonomy Jeremy Hatcher Follow this and additional works at the FSU Digital Library. For more information, please contact [email protected] FLORIDA STATE UNIVERSITY COLLEGE OF ARTS AND SCIENCES A REFLECTIVE, 3-DIMENSIONAL BEHAVIOR TREE APPROACH TO VEHICLE AUTONOMY By JEREMY HATCHER A Dissertation submitted to the Department of Computer Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy Degree Awarded: Spring Semester, 2015 © 2015 Jeremy Hatcher Jeremy Hatcher defended this dissertation on April 14, 2015. The members of the supervisory committee were: Daniel Schwartz Professor Directing Dissertation Emmanuel Collins University Representative Peixiang Zhao Committee Member Zhenghao Zhang Committee Member The Graduate School has verified and approved the above-named committee members, and certifies that the dissertation has been approved in accordance with university requirements. ii ACKNOWLEDGMENTS My most sincere gratitude belongs to Dr. Daniel Schwartz for taking the time to analyze my work and direct me toward its completion. When difficulties arose, his advice and recommendations were concise and helped to overcome any obstacles. I would also like to thank my family, whether immediate, extended, or my church family, who constantly encouraged me and repositioned my sight toward the light at the end of the tunnel. To all of the professors on my committee: Drs. Peixiang Zhao, Zhenghao Zhang, and Emmanuel Collins, I truly appreciate the time you set aside to meet with me and to understand my objectives. iii TABLE OF CONTENTS LIST OF TABLES ......................................................................................................................... vi LIST OF FIGURES ...................................................................................................................... vii LIST OF ACRONYMS ............................................................................................................... xiv ABSTRACT ................................................................................................................................. xvi 1 INTRODUCTION .............................................................................................................. 1 1.1 Underwater Acoustic Sensor Networks .......................................................................... 1 1.2 Underwater Robotic Behaviors – Automation vs. Autonomy ...................................... 11 1.3 Common Graph Searching Algorithms ........................................................................ 14 1.4 Behavior Trees .............................................................................................................. 17 1.5 ECMA-335 and ISO/IEC 23271 - Common Language Infrastructure ......................... 31 1.6 ECMA-334 and ISO/IEC 23270:2006 – C# ................................................................. 33 1.7 Modular Programming .................................................................................................. 34 1.8 Case Based Reasoning .................................................................................................. 39 1.9 XML .............................................................................................................................. 44 1.10 Reflection ...................................................................................................................... 51 2 RELATED WORK ........................................................................................................... 54 2.1 Behavior Architectures ................................................................................................. 54 2.2 Underwater Autonomy.................................................................................................. 60 2.3 Modular Open Systems ................................................................................................. 62 3 DEVELOPING A TEST PLATFORM ............................................................................ 73 3.1 Behavior Tree World (BTWorld) ................................................................................. 74 4 DEVELOPING WORLD ACTORS ................................................................................. 81 4.1 Vehicle Simulator (Traveler) ........................................................................................ 81 4.2 Acoustic Node Simulator (Communicator) .................................................................. 83 5 BEHAVIOR TREE FRAMEWORK IMPLEMENTATION ........................................... 85 5.1 Fundamental Interfaces ................................................................................................. 86 5.2 Asynchronous Operation .............................................................................................. 88 5.3 Composite Nodes .......................................................................................................... 89 5.4 Decorator Nodes ........................................................................................................... 90 5.5 Action / Assertion Nodes .............................................................................................. 91 5.6 Generic Counterparts .................................................................................................... 93 5.7 Action and Assertion Repositories................................................................................ 95 6 COMPOSING BEHAVIOR TREE ALGORITHMS ..................................................... 100 6.1 Breadth First Search .................................................................................................... 100 6.2 Dijkstra ........................................................................................................................ 104 6.3 A* ................................................................................................................................ 107 6.4 Reflective Behavior Tree Instantiation ....................................................................... 109 iv 7 BEHAVIOR TREE APPLICATION RESULTS ........................................................... 115 7.1 Path Planning .............................................................................................................. 115 7.2 Acoustic Node Mapping ............................................................................................. 119 7.3 REMUS Simulator Integration ................................................................................... 122 7.4 Performance Cost ........................................................................................................ 130 7.5 Algorithm Representation Potential ............................................................................ 132 8 CONCLUSION AND FUTURE RESEARCH POTENTIAL ........................................ 134 8.1 Conclusion .................................................................................................................. 134 8.2 Future Research Potential ........................................................................................... 134 REFERENCES ........................................................................................................................... 136 BIOGRAPHICAL SKETCH ...................................................................................................... 140 v LIST OF TABLES Table 1 - A simple model of an actor in a game of life example .................................................. 40 Table 2 - A simple model of the world in a game of life example ............................................... 41 Table 3 - A collection of cases in the case-base ........................................................................... 41 Table 4 - A CBR query based on current world variables ............................................................ 41 Table 5 – A world actor’s rationale for choosing a case from the case base ................................ 42 Table 6 - A modified CBR query taking into account a recent hardy meal.................................. 43 Table 7 - The resulting case base coefficients after taking the previous query into account ....... 43 Table 8 –XML escape characters .................................................................................................. 46 Table 9 – TDM Usability Questionnaire ...................................................................................... 59 Table 10 – Alignment of TaskStatus enum to NodeStatus enum ................................................. 89 Table 11 – Alignment of Boolean values to NodeStatus enum .................................................... 98 Table 12 - A line by line analysis of the Breadth First Search pseudo code revealing necessary behavior tree nodes ..................................................................................................................... 101 Table 13 - A line by line analysis of Dijkstra's algorithm pseudo code revealing necessary behavior tree nodes .................................................................................................................................... 105 Table 14 - A line by line analysis of the A* algorithm pseudo code revealing necessary behavior tree nodes ...................................................................................................................................