Gravity-Independent Locomotion:

Potential Approaches to Robotic Mobility on Asteroid Surfaces

Eddie Tunstel

Space Robotics & Autonomous Control LeadSpace Department

JHU-APL

Planetary Rovers WorkshopIEEE ICRA 2010

May 3, 2010

Anchorage, AK

Luther Palmer III

Assistant Professor, Biomorphic Robotics LabDepartment of Computer Science and Engineering

University of South Florida

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Motivation

Continuing campaign of small body exploration Orbit/rendezvous landing/touch-and-

go sampling surface exploration (as precursor mission payloads and as astronaut leave-behinds)

Opportunity to drive convergence of technology from different robotics application domains

Focus is on local mobility in persistent contact with the surface in high priority science regions

Artist’s concept of NEAR Shoemaker on surface of Eros

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Technology convergence

Disparate research efforts and missions (e.g., Hayabusa) are maturing enabling technology for asteroid mobility Hopping vehicles and various rover concepts Climbing robots for military recon. and search & rescue

Some point(s) of convergence seems possible now or in the near future for gravity-independent locomotion systems Locomotion without strict dependence on the local

gravity vector for traction or stability and local motion control

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Rolling & Hopping

See the paper for this talk for more discussion

T. Kubota and T. Yoshimitsu (ISAS/JAXA) Asteroid Exploration Rover, IEEE ICRA 2005, Planetary Rover Workshop

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Surface characteristics

Weak gravity (micro-g to milli-g) makes it difficult to achieve normal forces usually required for stable surface locomotion

A means to traverse subject to low ground contact pressure or to cling or stick the surface is needed

NEAR S/C final Eros landing mosaic

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Surface characteristics

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M. Yoshikawa et al (JAXA) COSPAR Capacity Building Workshop on Planetary Science, Montevideo, Uruguay, July 2007

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Crawling & Climbing

See the paper for this talk for more discussion

R. Wagner (IEEE ICRA 2007Planetary Rover Workshop

LEMUR IIb (JPL)

AWIMR (NGST, JPL, CMU)

ASTRO on microgravity emulation testbed

(Tohoku University)M. Chacin & K. Yoshida

IEEE ICRA 2009

B. Kennedy (CLAWAR 2005

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Relevant Climbers for Earth-based applications

Gecko-inspired dry adhesives (potential for rapid, low-energy attachment/detachment on various surfaces)

microspine array, or the single spine or claw (latch onto asperities in the surface or dig into soft substrates)

electroadhesion (electrically controllable adhesion between compliant electrodes and various surfaces)

For Earth applications a remaining challenge is producing a single foot and adhesion paradigm that can climb on a variety of both man-made and natural surfaces

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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Relevant Climbers for Earth-based applications

DIGbot videos

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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CHALLENGES

Mechanics of controlled ballistic hopping on rotating asteroids and in non-uniform gravity fields

Landing after hopping in such a way as to avoid rebound

Maintaining grip or temporary anchoring while controlling force for closure and compliance

Determining, updating and maintaining knowledge of rover position

Testing and verification of gravity-independent locomotion systems

J. Bellerose & D. Sheeres (U. Mischigan, Ann Arbor)

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Conclusions

Technical challenges can be met with recent technological advances in robotics research

The space of candidate technologies is rich Earth-based research is advancing useful designs

and capabilities (dry adhesive, electroadhesion, and gripping spine)

More attention from the space robotics community is warranted to provide the most capable solutions for science support

Conceivably, solutions for small body mobility would also be applicable for hard-to-access terrain (e.g., cliff faces, crater walls, and caves) on larger

planetary bodies.