Lunar Drilling and Driving Carnegie Mellon 13-14 December 2007 Red Whittaker

Lunar Drilling and DrivingCarnegie Mellon13-14 December 2007

Red Whittaker

Carnegie Mellon | 13 December 2007 3

Mission Scenario

• Land on crater floor• Operate in perpetual darkness• Multiple drill-drive cycles





Coring

• 1 meter drilling– ø30 cm borehole– ø1.5 cm continuous core– ~50 kg– 0.5 m x 0.5 m x 1.5 m volume

• Operations:– Drill to depth– Capture core, transfer– Chop core segments– Crush– Load oven


Coring, Crushing, Baking, Analysis

CoringSampletransfer

Metering Crushing Baking ExtractionSensing





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Polar Scenario

• Land in crater – Direct to floor, no crater wall descent– Minimal lander

• Communicate by polar orbiter relay• Power from isotope source, no solar• Navigate in darkness

– Active sensing using laser light-striping

• Operate with supervised autonomy• Survey multiple locations

– Characterize regolith composition and physical properties– Determine nature and abundance of hydrogen

• Survive 7 months– 25 drill sites x (5 days/site, 3 days/traverse) = 200 days

• Mass 200-300 kg


Issues for Robotic Drilling

• Drill dominated Robot Design– Stiffness & Reaction to drill– Crouching to lower drill before boring

• Mobility over rough terrain– Suspension and flotation for lunar terrain– Sensing and operation in darkness

• Power– Radioisotopic power scenario


Mass and Scaling of Robot

Robot weight on lunar surface enables drillingApplied thrust

Resisted torque


Scarab Rover





System attributes

• Drill implementation– Central location on vehicle to maximize weight for downforce– Direct mounting to chassis– Fixed drill structure

• Reduced actuation• Functions as navigation mast• Simplifies kinematics & mass properties

• Adjustable kinematic suspension– Body roll averaging over terrain– Bring drill to surface to operate– High stiffness platform to react drilling forces

• Skid steering– Reduced actuation– Increased stiffness

• Thermal approach– Utilize heat from radioisotope power supply – Shunt excess heat to radiator surface


Straddling


Drilling


Pose adjustment mechanism

• Raises & lowers by actuating wing angle (independent L & R)• Center link bisects wing angle: enables lift-and-level body averaging• Retains advantages of passive rocker bogie







Leveling





Differencing





Objectives

• Develop Drill-dominated Mobility– Accommodate drill and sample processing payload– Stabilize mechanism during drilling– Access sites of interest

• Address Lunar Polar Considerations– Operation in darkness

• No solar power

• Constant low-temperature (80K)

• Active perception

– Mission relevant concept• Multiple drill-drive cycles over kilometer scale

• Rover scale and mass


Vehicle requirements

• Drill dominated design– Bring drill to surface to operate– High stiffness platform to react forces

• Mobility over rough terrain– 30 cm obstacles– Steep soil slopes

• Environments– Fine, abrasive dust– Vacuum, 40 K ground, 3 K sky

• Power– Radioisotopic power supply


Integrated Driving and Drilling

• Drill implementation– Central location on vehicle to maximize weight for downforce– Direct mounting to chassis– Fixed drill structure

• Reduced actuation• Functions as navigation mast• Simplifies kinematics & mass properties

• Adjustable kinematic suspension– Body roll averaging over terrain– Bring drill to surface to operate– High stiffness platform to react drilling forces

• Skid steering– Reduced actuation– Increased stiffness

• Thermal approach– Utilize heat from radioisotope power supply – Shunt excess heat to radiator surface


Specifications

Mass: 280 kg Weight: 460 N 2750 N

Power (driving): 200 W (peak) Power (posing): 380 W (peak) Power (idle): 78 W

Speed: 5.0 cm/s (6.0 cm/s max)

Height (with drill tower): 2.2 m high stance, 1.6 m low stanceWidth (wheelbase): 1.4 mLength (wheelbase): 0.8 - 1.3 m Aspect (track/wheelbase): 1:1 low stance, 1:2 nominal, 1:7 highWheel diameter: 60 cm


Specifications

CG height: 0.64m nominal, 0.60m low, 0.72m high

Static pitchover: 42° nominal stance, 29° high, 45° low Static rollover: 53° nominal stance, 48° high, 55° low

Maximum / minimum straddle: 57 cm, Belly contact

Approach / departure angle: 105° nominal stanceBreakover angle: 115° nominal stance

Rim pull (single wheel): 2500 NDrawbar pull: 1560 N (medium-coarse grain sand)


Driving in the dark

• Localization– Rim camera

• Terrain Mapping and Obstacle Detection– Light striping (front/rear)– Both horizontal and vertical stripes for terrain mapping while driving

straight and turning

• Imaging– Flash stereo / Flash ladar– Mounted on a pan/tilt for 360º coverage

• Dead reckoning / mapping support– IMU– Wheel encoders

• Workspace imager– Underbelly mounted camera with LED illumination



Future Evolutions

• Internal actuation; eliminate external wiring;Shaft-drive• Actuated suspension to surmount extreme obstacle or

extricate from twist• Space-relevant wheels & tread: design, fab, mount• Hosting more of RESOLVE subsystems• Adding Nav sensors and position estimation from rim• Increase dimensions of chassis and body-averaging beam• Thermal isolation of cold drill and warm body• Use Scarab to load RESOLVE experiments• ‘Inchworm’ locomotion

Documents

Lunar Drilling and Driving Carnegie Mellon 13-14 December 2007 Red Whittaker