A HYBRID VEHICLE FOR AERIAL AND TERRESTRIAL LOCOMOTION by Richard J. Bachmann Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Dissertation Advisor: Dr. Roger D. Quinn Department of Mechanical Engineering Case Western Reserve University May, 2008 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of _____________________________________________________ candidate for the ______________________degree *. (signed)_______________________________________________ (chair of the committee) ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ (date) _______________________ *We also certify that written approval has been obtained for any proprietary material contained therein. Table of Contents Section Page Chapter 1 Introduction..................................................................................................1 1.1 Motivation.............................................................................................................2 1.1.1 Chemical or Biological Weapon Source Localization....................................2 1.1.2 Ad hoc Sensor Network Deployment .............................................................2 1.1.3 Search and Rescue..........................................................................................3 1.1.4 Hazardous Environment Exploration..............................................................3 1.1.5 Hostage Situations..........................................................................................4 1.1.6 Medium field military situational awareness..................................................4 1.2 Biological Inspiration............................................................................................5 1.3 Organization of this document..............................................................................6 Chapter 2 Background..................................................................................................7 2.1 Micro Terrestrial Vehicles ....................................................................................7 2.2 Miniature Air Vehicles .......................................................................................11 2.2.1 Flapping Wings.............................................................................................12 2.2.2 Rigid Wings ..................................................................................................13 2.2.3 Flexible Fixed Wings....................................................................................14 2.3 Hybrid Amphibious Vehicles .............................................................................15 2.4 Hybrid Aerial/Terrestrial Vehicles .....................................................................16 Chapter 3 The First Prototype ....................................................................................18 3.1 Locomotion Subsystem Selection.......................................................................18 3.2 Multi-Modal Mobility Tradeoffs ........................................................................20 3.2.1 Single Source Propulsion..............................................................................22 3.2.2 Wheel-legs ....................................................................................................23 3.2.3 Steering .........................................................................................................24 3.2.4 Wings ............................................................................................................25 3.3 Design Process....................................................................................................26 3.3.1 Terrestrial Drive System...............................................................................26 3.3.2 Sensor system................................................................................................27 3.3.3 Fuselage ........................................................................................................27 3.3.4 Wing..............................................................................................................28 3.4 Fabrication Process.............................................................................................29 3.4.1 Wing and Tail ...............................................................................................29 3.4.2 Fuselage ........................................................................................................31 3.4.3 Wheel-legs ....................................................................................................33 3.5 Results.................................................................................................................34 3.6 Critical Analysis of Prototype Hybrid Vehicle...................................................40 3.6.1 Primary Goals...............................................................................................41 3.6.1.1 Autonomous Operation..........................................................................41 3.6.1.2 Improved Durability..............................................................................42 3.6.1.3 Repeatable Fabrication and Assembly Procedures................................43 3.6.2 Secondary Goals...........................................................................................43 3.6.2.1 Improved Deployment ...........................................................................43 3.6.2.2 Enhanced Flight Performance................................................................44 i Table of Contents Section Page 3.6.2.3 Improved Wing Folding.........................................................................44 3.6.2.4 Ground Take-off....................................................................................44 3.6.2.5 Tail Hook...............................................................................................45 Chapter 4 Airframe Mechanical Design.....................................................................46 4.1 Fuselage Mold Fabrication .................................................................................47 4.2 Component Mounting.........................................................................................50 4.2.1 Motor Nacelle...............................................................................................51 4.2.2 Tail Boom.....................................................................................................53 4.3 Tail ......................................................................................................................55 4.3.1 Assembly.......................................................................................................55 4.3.2 Alignment .....................................................................................................56 4.3.3 New Tail Design ...........................................................................................57 4.4 Component Placement ........................................................................................58 4.5 Results.................................................................................................................59 Chapter 5 Terrestrial Running Gear Design...............................................................61 5.1 Larger direct drive system ..................................................................................62 5.2 Indirect Drive System .........................................................................................63 5.3 Slip-clutch Hub...................................................................................................65 5.4 Angled Slip-clutch Hub ......................................................................................66 5.5 Parallel Shaft O-ring Slip-clutch.........................................................................67 5.5.1 Test Apparatus for Torque Transmission Measurement...............................67 5.5.2 Test Procedure for Torque Limiter Evaluation.............................................68 5.6 Concentric Shaft O-ring Slip-Clutch ..................................................................71 5.7 Wheel-legs ..........................................................................................................74 5.8 Results.................................................................................................................75 Chapter 6 Airframe Aerodynamic Design..................................................................76 6.1 Wing and Aerodynamic Property Tests..............................................................76 6.1.1 Purpose..........................................................................................................76 6.1.2 Test Apparatus and Set-up............................................................................77 6.1.3 Data Collection and Analysis........................................................................80 6.1.4 Wing Testing Procedure ...............................................................................81 6.1.4.1 Independent Wing Test Results .............................................................82 6.1.4.2 Wind Tunnel Testing of Aerial Platform...............................................83