Dynamic Anchoring in Soft Regolith: Testing and Prediction
Publication: Journal of Aerospace Engineering
Volume 31, Issue 2
Abstract
In recent decades, the exploration of celestial bodies has moved to surface-based landers and rovers designed to perform experiments on the ground. The presented research focuses on legged rovers designed to climb steep slopes covered in uncompacted regolith, similar to those found on lunar crater walls. These rovers would claw into the surface using dynamic anchors on their feet. Physical testing is performed by engaging a series of anchors with lunar simulant. Multiple anchor configurations are tested and evaluated to determine the geometries with the most beneficial characteristics for dynamic anchoring. Several anchor geometries show sufficient holding forces for use on future legged exploration rovers. Additionally, two methods for predicting the anchoring forces with limited knowledge of the regolith are presented, one using discrete elements, the other regression curve-fitting. Both methods show a prediction accuracy for peak anchoring forces well within an order of magnitude.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors would like to thank Roy Lichtenheldt of the German Aerospace Center (DLR) for providing guidance on setup parameters for the DEM simulation as well as AJ Nick, Matt Nugent, and Kevin Ricksecker at the SwampWorks laboratory of NASA’s Kennedy Space Center for providing assistance with setting up and executing the various tests. Thanks also go to the Kennedy Graduate Fellowship Program of the National Aeronautics and Space Administration for providing funding for this research.
References
Abad-Manterola, P., Burdick, J. W., Nesnas, I. A. D., and Cecava, J. (2009). “Wheel design and tension analysis for the tethered axel rover on extreme terrain.” Proc., Aerospace Conf., IEEE, New York.
Anderson, R. (2015). “Sol 1112-1113: Rough driving.” ⟨http://mars.nasa.gov/msl/mission/mars-rover-curiosity-mission-updates⟩ (Oct. 2, 2015).
Andrews, D. (2015). “Lunar crater observation and sensing satellite (LCROSS).” ⟨http://lcross.arc.nasa.gov⟩ (Sep. 5, 2015).
Asbeck, A. T. (2010). “Compliant directional suspension for climbing with spines and adhesives.” Ph.D. thesis, Stanford Univ., Stanford, CA.
Asbeck, A. T., Kim, S., McClung, A., Parness, A., and Cutkosky, M. R. (2006). “Climbing walls with microspines.” Proc., Int. Conf. on Robotics and Automation, IEEE, New York.
ASTM. (2016). “Standard test methods for minimum index density and unit weight of soils and calculation of relative density.” ASTM D4254–16, West Conshohocken, PA.
Aubeny, C. P., and Chi, C. (2010). “Mechanics of drag embedment anchors in a soft seabed.” J. Geotech. Geoenviron. Eng., 136(1), 57–68.
Cundall, P. A., and Strack, O. D. (1979). “A discrete numerical model for granular assemblies.” Geotechnique, 29(1), 47–65.
Ebert, T. (2017). “Dynamic anchoring in soft regolith for celestial exploration.” Ph.D. thesis, Florida Institute of Technology, Melbourne, FL.
Ebert, T., and Larochelle, P. (2016a). “Simulation of soft regolith dynamic anchors for celestial exploration.” Proc., Aerospace Conf., IEEE, New York.
Ebert, T., and Larochelle, P. (2016b). “Testing of soft regolith dynamic anchors for celestial exploration.” Proc., Earth and Space, ASCE, Reston, VA.
Hand, E. (2014). “Philae probe makes bumpy touchdown on a comet.” Science, 346(6212), 900–901.
Knuth, M., Johnson, J., Hopkins, M., Sullivan, R., and Moore, J. (2011). “Discrete element modeling of a Mars exploration rover wheel in granular material.” J. Terramech., 49(1), 27–36.
LabVIEW [Computer software]. National Instruments, Austin, TX.
Lichtenheldt, R., and Schäfer, B. (2013a). “Locomotion on soft granular soils: A discrete element based approach for simulations in planetary exploration.” Proc., 12th Symp. on Advanced Space Technologies in Robotics and Automation, ESA/ESTEC, Noordwijk, Netherlands.
Lichtenheldt, R., and Schäfer, B. (2013b). “Planetary rover locomotion on soft granular soils—Efficient adaptation of the rolling behavior of nonspherical grains for discrete element simulations.” Proc., III Int. Conf. on Particle-Based Methods—Fundamentals and applications, IACM, Barcelona, Spain.
Mueller, R. P., Cox, R. E., Ebert, T., Smith, J. D., Schuler, J. M., and Nick, A. J. (2013). “Regolith advanced surface systems operations robot (RASSOR).” Proc., Aerospace Conf., IEEE, New York.
Naval Civil Engineering Laboratory. (1987). Drag embedment anchors for navy moorings, Vol. 83, Port Hueneme, CA.
PFC3D 4.0 [Computer software], ITASCA, Minneapolis.
PFC3D 5.0 [Computer software], ITASCA, Minneapolis.
Rahmatian, L. A., and Metzger, P. T. (2010). “Soil test apparatus for lunar surfaces.” Proc., Earth and Space: Engineering, Science, Construction, and Operations in Challenging Environments, ASCE, Reston, VA.
Sane, A., Wasfy, T. M., Wasfy, H. M., and Peters, J. M. (2015). “Coupled multibody dynamics and discrete element modeling of bulldozers cohesive soil moving operation.” Proc., Int. Design Engineering Technical Conf. and Computers and Information in Engineering Conf., ASME, New York.
Smith, W., and Peng, H. (2015). “A surrogate discrete element method for terramechanics simulation of granular locomotion.” Proc., Int. Design Engineering Technical Conf. and Computers and Information in Engineering Conf., ASME, New York.
Suescun-Florez, E., Roslyakov, S., Iskander, M., and Baamer, M. (2014). “Geotechnical properties of BP-1 lunar regolith simulant.” J. Aerosp. Eng., 04014124.
Wasfy, T. M., Wasfy, H. M., and Peters, J. M. (2014). “Coupled multibody dynamics and discrete element modeling of vehicle mobility on cohesive granular terrains.” Proc., Int. Design Engineering Technical Conf. and Computers and Information in Engineering Conf., ASME, New York.
Watanabe, S. (2015). “Phoenix Mars lander.” ⟨http://www.jpl.nasa.gov/news/phoenix/main.php⟩ (Oct. 2, 2015).
Wong, J. (2012). “Predicting the performances of rigid rover wheels on extraterrestrial surfaces based on test results obtained on Earth.” J. Terramech., 49(1), 49–61.
Wong, J., and Kobayashi, T. (2012). “Further study of the method of approach to testing the performance of extraterrestrial rovers/rover wheels on Earth.” J. Terramech., in Press.
Information & Authors
Information
Published In
Journal of Aerospace Engineering
Volume 31 • Issue 2 • March 2018
Copyright
©2017 American Society of Civil Engineers.
History
Received: Dec 20, 2016
Accepted: May 26, 2017
Published online: Nov 22, 2017
Published in print: Mar 1, 2018
Discussion open until: Apr 22, 2018
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.