DESIGN AND PRODUCTION OF A 3-D PRINTED WIRELESS HEXAPOD A Major Qualifying Project Report: Submitted to the Faculty of the WORCESTER POLYTECHNIC INSTITUTE in partial fulfillment of the requirements for the Degree of Bachelor of Science by Andrew Beaupre Tyler Collins Aras Nehir Keskin Cody Woodard-Wallace Date: April 30th 2015 Approved By: ____________________________________ Prof. David C. Planchard, Project Advisor Table of Contents Table of Contents ........................................................................................................................................... i Table of Figures ............................................................................................................................................ iii Table of Tables .............................................................................................................................................. v Nomenclature .............................................................................................................................................. vi Abstract ....................................................................................................................................................... vii Introduction .................................................................................................................................................. 1 Background ................................................................................................................................................... 2 Components of a Hexapod ....................................................................................................................... 2 Gait Styles ................................................................................................................................................. 3 Benchmarking ........................................................................................................................................... 4 RHex Robot ........................................................................................................................................... 6 DASH Robot ........................................................................................................................................... 8 RoACH Hexapod Robot ....................................................................................................................... 10 Methods and Procedure ............................................................................................................................. 13 Design Goals and Project Objectives ...................................................................................................... 13 Design Specifications .......................................................................................................................... 13 Gait Style Selection ............................................................................................................................. 14 Conceptual Designs ................................................................................................................................. 16 Design 1 ............................................................................................................................................... 16 Design 2 ............................................................................................................................................... 17 Selection of Final Design ......................................................................................................................... 18 Electrical Design ...................................................................................................................................... 19 Arduino Controller .............................................................................................................................. 19 Motors and Motor Drivers .................................................................................................................. 21 Communication ................................................................................................................................... 23 Power .................................................................................................................................................. 27 Range Testing ...................................................................................................................................... 29 Leg Orientation Issues ......................................................................................................................... 31 Materials Research ................................................................................................................................. 32 Assessing the Viability of 3-D Printing Materials ................................................................................ 32 Heat Testing ........................................................................................................................................ 33 Rapid Prototyping ................................................................................................................................... 35 i Introduction ........................................................................................................................................ 35 Printed Parts Overview ....................................................................................................................... 36 Additive Manufacturing of the Parts .............................................................................................. 37 Frame (Part no. 1) ........................................................................................................................... 37 Universal Joint Rings (Part no. 2) .................................................................................................... 40 Ball-Socket Joint (Part no. 3) ........................................................................................................... 42 Lower Leg (Part no. 4) ..................................................................................................................... 43 Idler Gear and Spur Gear (Part no. 5 and 6) ................................................................................... 44 Gear Mount (Part no. 7) .................................................................................................................. 45 Driving Gear (Part no. 8) ................................................................................................................. 46 Motor Mount (Part no. 9) ............................................................................................................... 48 Conclusion ....................................................................................................................................... 50 Controller Box ..................................................................................................................................... 50 Calculations ............................................................................................................................................. 52 Expected mass of 3-D printed components ........................................................................................ 52 Forces due to the weight of the body and additional components ................................................... 52 Force acting on each leg due to weight of robot ................................................................................ 53 Finite Element Analysis – Stress Concentrations ................................................................................ 54 Reaction forces due to weight of the robot ........................................................................................ 56 Frictional Force (Static) ....................................................................................................................... 57 Frictional Force to Overcome (Dynamic) ............................................................................................ 57 Torque Required to Overcome the Force from Weight ...................................................................... 58 Factor of Safety of the Motor ............................................................................................................. 59 Motor Selection .................................................................................................................................. 59 Conclusions ................................................................................................................................................. 61 Prototype Assessment ............................................................................................................................ 61 Future Work ............................................................................................................................................ 62 Appendices .................................................................................................................................................. 64 Appendix A: Program Code ..................................................................................................................... 64 Hexapod Code ....................................................................................................................................