1. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Rover Chassis Life in the Atacama Design Review December 19, 2003 Stu Heys, Dimi Apostolopoulos

2. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Description and Motivation A new rover chassis for mobility and science is to replace Hyperion in the upcoming campaigns That is motivated by the need to Accommodate various science instruments Improve mobility especially in inclined terrain Optimize propulsion subsystem

3. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Key Requirements & Design Drivers Provide unobstructed FOV and necessary actuated motions for science payloads Modify wheel design to improve terrainability Increase wheel torque to improve slope climbing Increase rover speed to decrease traverse times Eliminate drivetrain hysteresis to improve control Minimize mechanical complexity. Maintain as much of Hyperion’s design as possible Design for 150 kg GVW

4. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Building on Hyperion’s Competencies HyperionNew Rover 4 driven wheels, brushless DCSame Chain drive 5+ cm hysteresis in drive system Coaxial drive zero hysteresis, fewer parts 1 degree of steer motion 3.5m turn radius 2 symmetrical degrees 2.5m turn radius 1 degree of roll freedom inconsistent performance over rough terrain chassis receives direct shocks from bumps 2 degrees of roll with averaged chassis chassis somewhat isolated from shocks each wheel performs identically in rough terrain

5. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon New Rover Configuration Steer and roll articulation at front and rear Pan and tilt unit base atop forward leaning mast ~2.3m 2 solar array Fluorescence imager location.85m range of motion ~.32m 3 electronics enclosure roughly equal in volume to Hyperion Drivetrain completely enclosed by axle structure

6. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Steering & Articulation Chassis averages as front tire climbs 30cm obstacle

7. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Evaluation of Steering Geometries

8. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Linear table spans frame members, supports fluorescence imager Sensor & Solar Panel Configuration Sub panels slide out of frames with integrated electrical connections Panels fold up for easy access to e- box and science instruments Science instruments isolated from vehicle controls Electronics box nestled between frame members

9. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Technical Approach Prototype chassis roll mechanism Tune-up controller to optimize mobility Utilize test results to finalize detailed design of axles and pivots Define volumetric and instrument functional requirements Finalize sensor placement configuration Detail design chassis for optimal accommodation of the solar panels, electronics and science instruments Design mechanism for fluorescence imager and pan/tilt unit Integrate prototype instrument deployment mechanism on Hyperion FEA results for axle

10. Life in the Atacama, Design Review, December 19, 2003 Carnegie Mellon Design & Implementation Issues Complex Integration Science payloads (esp. fluorescence imager) 2+ degree of freedom Mast (in-house pan & tilt design) Design for 4+ cameras Solar panels Optimized for cell size while avoiding wheel interferences Plow Tricky deployment issues