Dynamic Modeling of the Chariot Suspension System Joseph Shoer / ES6 Exit Presentation 7 August 2009

Introduction ADAMS Model Capabilities The Future Introduction Personal Background

Introduction ADAMS Model Capabilities The Future Magnetic Flux Pinning  Autonomous docking  Modular self-assembly  Large-scale structures  System reconfiguration Introduction Space Systems Research at Cornell

Introduction ADAMS Model Capabilities The Future Introduction Chariot Small Pressurized Rover (SPR)

Introduction ADAMS Model Capabilities The Future Introduction Chariot Small Pressurized Rover (SPR)  Planetary surface exploration requires mobility  SPR allows extended (days-weeks) traverses with high visibility and relatively easy ingress/egress  Traverse rugged planetary terrains to high science value targets  ES supports ER in Gen 1 concept analysis and Gen 2 vehicle development Chariot Rover Development

Introduction ADAMS Model Capabilities The Future Introduction Chariot Small Pressurized Rover (SPR)  Stress, loads and design support prior to Gen 2  Support Gen 1 Rover failure analyses  Support Gen 2 design recommendations  Develop FEM component models  Cabin pressure vessel  Develop rigid body model ES Rover Involvement

Introduction ADAMS Model Capabilities The Future Introduction Chariot Small Pressurized Rover (SPR)  Stress, loads and design support prior to Gen 2  Support Gen 1 Rover failure analyses  Support Gen 2 design recommendations  Develop FEM component models  Cabin pressure vessel  Develop rigid body model ES Rover Involvement Focus on Suspension System

Introduction ADAMS Model Capabilities The Future Introduction Develop a dynamic model of the vehicle suspension to help understand dynamic loads on the suspension system in the operating environment. This will promote optimal vehicle design in Gen 2 development. Objective

Introduction ADAMS Model Capabilities The Future ADAMS Model ADAMS Model Components

Introduction ADAMS Model Capabilities The Future 210 kg each Wheel modules ADAMS Model ADAMS Model Components 960 kg Cabin 210 kg Frame 1200 kg total Nonstructural masses 740 kg Balance 24 cm forward CG

Introduction ADAMS Model Capabilities The Future ADAMS Model Suspension System Dynamic Model

Introduction ADAMS Model Capabilities The Future ADAMS Model Suspension System Dynamic Model

Introduction ADAMS Model Capabilities The Future Joints with 5DOF stiffness ADAMS Model Four-bar linkages Suspension System Dynamic Model Spring Ground Vehicle weight

Introduction ADAMS Model Capabilities The Future ADAMS Model Suspension System Dynamic Model  Key component for loads  Previous failure analysis  FEM in development (Photo: Leslie Schaschl/ES4) Back Plate

Introduction ADAMS Model Capabilities The Future  Stiffness: 600 lbf/in  Damping from data ADAMS Model Passive spring/dampers Suspension System Dynamic Model

Introduction ADAMS Model Capabilities The Future ADAMS Model Ball ScrewMotor Suspension System Dynamic Model  Moves along ball screw (Change spring endpoint)  Actuates suspension angle Screw Rail

Introduction ADAMS Model Capabilities The Future  Wheel module / frame  Tire stiffness from data  Simple tire damping  Tire/ground friction  Constant speed rotation Tire-ground contact ADAMS Model Fixed joint Suspension System Dynamic Model Wheel drive motion Crab angle

Introduction ADAMS Model Capabilities The Future Simulation Capabilities: Dynamic Behaviors Capabilities

Introduction ADAMS Model Capabilities The Future Simulation Capabilities: Dynamic Behaviors Capabilities

Introduction ADAMS Model Capabilities The Future Simulation Capabilities: Result Sets Extract Forces in Joints or Bodies Extract Torques in Joints or Bodies Capabilities ADAMS can also extract stresses in flex bodies

Introduction ADAMS Model Capabilities The Future Capabilities Simulation Capabilities: Active Suspension

Introduction ADAMS Model Capabilities The Future  Improve nonstructural mass distribution  Improve tire/ground interaction model (“Sinking” issue, ground and tire materials)  Improve active control implementation (Sensor, motor dynamics; control law) The Future Model Fidelity Improvements

Introduction ADAMS Model Capabilities The Future  Implement additional control modes (steering assist, climbing, etc)  Include FEM flexible bodies (back plate, bushings, etc)  Add runtime wheel steering (run test courses) The Future Model Extension Possibilities

Introduction ADAMS Model Capabilities The Future  Add wireless instrumentation to vehicle  Characterize suspension accelerations  Input to model The Future Experimental Correlation

Introduction ADAMS Model Capabilities The Future Conclusions  ES6 now has a multibody dynamics model for the six-wheeled SPR  This model promises excellent possibilities for improvement and extension  This model can provide stress and load information under dynamic conditions, which will feed into optimization and development for the Gen 2 rover

Introduction ADAMS Model Capabilities The Future Alex Tovar Tim Rupp John Schliesing Ed Herrera Beverly Haygood Courtney Crooks Some images from EA Imagery Online library Acknowledgments

Dynamic Modeling of the Chariot Suspension System Joseph Shoer / ES6 Exit Presentation 7 August 2009