A Biologically Inspired Robot for Assistance in Urban Search and Rescue by ALEXANDER HUNT Submitted in partial fulfillment of the requirements For the degree of Master of Science in Mechanical Engineering Advisor: Dr. Roger Quinn Department of Mechanical and Aerospace Engineering CASE WESTERN RESERVE UNIVERSITY May 2010 Table of Contents A Biologically Inspired Robot for Assistance in Urban Search and Rescue ...................................... 0 Table of Contents ............................................................................................................................. 1 List of Tables .................................................................................................................................... 3 List of Figures ................................................................................................................................... 4 Acknowledgements.......................................................................................................................... 6 Abstract ............................................................................................................................................ 7 Chapter 1: Introduction ................................................................................................................... 8 1.1 Search and Rescue ................................................................................................................. 8 1.2 Robots in Search and Rescue ................................................................................................. 9 1.3 Identified Specifications ....................................................................................................... 10 1.4 Robotic Locomotion ............................................................................................................. 13 Chapter 2: Background .................................................................................................................. 15 2.1 Reduced Actuation Robots .................................................................................................. 15 2.2 Search and Rescue Robots ................................................................................................... 20 2.3 Situational Awareness Mast ................................................................................................ 23 Chapter 3: Design and Manufacturing of USAR WhegsTM ............................................................. 25 3.1 Working Model Simulations ................................................................................................. 26 3.2 Chassis .................................................................................................................................. 30 3.3 Locomotion .......................................................................................................................... 34 3.4 Gearing ................................................................................................................................. 40 3.5 Torsion Device ...................................................................................................................... 40 Internal Linear Spring Design 1 .............................................................................................. 42 Internal Linear Spring Design 2 .............................................................................................. 43 External Linear Spring Design ................................................................................................ 44 Torsion Spring Design ............................................................................................................ 45 Comparison ............................................................................................................................ 46 Pursued Designs ..................................................................................................................... 47 3.6 Wheel-Legs ........................................................................................................................... 50 3.7 Electronics ............................................................................................................................ 61 Chapter 4: Tests ............................................................................................................................. 66 1 4.1 Wheel-Leg Test .................................................................................................................... 66 4.2 Lab Runs ............................................................................................................................... 68 Chapter 5: Results .......................................................................................................................... 70 5.1 Specifications ....................................................................................................................... 70 5.2 Wheel-Leg Test Results ........................................................................................................ 73 5.3 Lab Runs Results .................................................................................................................. 75 Tracks ..................................................................................................................................... 75 Wheel-legs ............................................................................................................................. 76 Chapter 6: Conclusions and Future Work ...................................................................................... 79 6.1 Conclusions .......................................................................................................................... 79 6.2 Future Work ......................................................................................................................... 79 Appendix A. Motor calculations ................................................................................................. 81 Torque Calculations ............................................................................................................... 81 Speed Calculations ................................................................................................................. 82 Motor Chosen ........................................................................................................................ 82 Appendix B. Shaft Calculations ................................................................................................... 83 Weight Calculations ............................................................................................................... 83 Torque Calculations ............................................................................................................... 84 Works Cited .................................................................................................................................... 87 2 List of Tables Table 2.1 Power to mass ratio, and speed comparison of several legged robots (Allen, 2004), (Saranli, Buehler, & Koditschek, 2001). ...................................................................... 18 Table 5.1 - Comparison of WhegsTM I, WhegsTM II, Lunar WhegsTM, and USAR WhegsTM across several areas of interest ............................................................................................. 72 Table 5.2 - Weight of various sections of USAR WhegsTM .................................................... 72 Table 5.3 - Vertical displacement of center for all 3 specimens in position 1 ....................... 73 Table 5.4 - Horizontal displacement of center for all 3 specimens in position 1 ................... 73 Table 5.5 - Vertical displacement of all 3 specimens in position 2 ........................................ 74 Table A.1 - Data of Maxon RE 40, 150W motor and 26:1 planetary gear set ........................ 82 3 List of Figures Figure 1.1 - Comparison of ground compaction between a wheel and a leg (Martin-Alvarez, De Peuter, Hillebrand, Putz, Matthyssen, & de Weerd, 1996). ...................................................... 14 Figure 2.1 - Prolero .................................................................................................................... 16 Figure 2.2 – Rhex (Saranli, Buehler, & Koditschek, 2001) .......................................................... 17 Figure 2.3 - WhegsTM II ............................................................................................................. 19 Figure 2.4 - Dagsi WhegsTM ...................................................................................................... 20 Figure 2.5- Inuken VGTV shown in three positions ................................................................... 21 Figure 2.6 - iRobot Packbot with arm and camera extensions .................................................. 22 Figure 2.7 - OmniTread OT-8 climbing stairs ............................................................................. 23 Figure 2.8 - SAM8 on Packbot .................................................................................................... 24 Figure 3.1 - Robot in final configuration next to graduate student ........................................... 25 Figure 3.2 - Comparison of a wheel and a wheel-leg climbing an obstacle (Allen, 2004). ........ 26 Figure 3.3 - Fastest climbing configurations for (a) 1.0r, (b) 1.1r, (c) 1.2r and