Watch this bio-inspired Mars rover concept 'swim' through sand on curved wheels (video)
A novel approach to scouting the sand dunes of Mars is the Valles Marineris Explorer - or VaMEx. VaMEx is a project of the German Space Agency at the German Aerospace Center (DLR). The goal of the initiative is to blueprint an autonomous, heterogeneous robot swarm for exploring Valles Marineris on Mars — heralded as the "Grand Canyon" on the Red Planet.
Valles Marineris is an enormous rift valley system on Mars that scientists want to scour for traces of liquid water, which may exist in sheltered niches and serve as an habitat for possible life. But the region is difficult to investigate due to its topography, which poses challenges for robotic surveying.
But the VaMEx team is exploring combinations of driving, walking, and flying systems to leverage what each concept brings to the table in terms of jointly investigating a large area with varied environmental characteristics. One unique approach the team is exploring is a Mars rover that is outfitted with inventive curved wheels, which, like the feet of a desert lizard, can "swim" through sand.
A University of Würzburg research group has picked up on the sandfish's way of locomotion, adopting and adapting that movement into a Mars rover that reportedly outperforms other ways of navigating across sand.
Collaborating with DLR researchers in Bremen, Germany, University of Würzburg specialists have designed rover wheels that imitate the sandfish mobility characteristics and interaction with the ground, generating both longitudinal and lateral forces. That movement leaves sinusoidal, or S-shaped tracks in the sand.
Bio-inspired
Mars machinery must cope with sand, gravel, slopes, and generally uneven terrain while maintaining their mobility, stability, and efficiency.
Marco Schmidt, a university computer scientist and head of the Chair of Embedded Systems and Sensors for Earth Observation (ESSEO), is leading the bio-inspired mobility research.
Schmidt's team tested the rover on sand and in open terrain, working with the German Research Center for Artificial Intelligence in Bremen and the University of Bremen.
The results showed that the vehicle moves stably on sand, however, the experiments also spotlighted clear indications for improvements, Schmidt says.
The sandfish locomotion idea has been adopted from Scincus scincus, a lizard found in the Sahara desert that is able to burrow and then literally "swim" through the desert sand to hunt or escape predators.
Mobility solutions
Work on the mobility technique is ongoing at the university, with further refinements predicted to improve performance on mixed terrain. The ESSEO team aims to expand its contribution to VaMEx towards software-driven mobility.
Research plans also call for development of control strategies that explicitly take into account slippage, sinking and the interaction between terrain and wheel. An outcome would be more stable and adaptable behavior of the rover in granular environments.
"Creating mobility solutions that can reliably and efficiently drive across vast dune fields on Mars, not just in Valles Marineris, but across the planet, is key for future Mars exploration, both robotic and crewed," adds Pascal Lee of the SETI Institute, Mars Institute, Ceres Robotics, and NASA Ames Research Center, who is not associated with this study.
"This bio-inspired technology development is both innovative and intriguing," Lee told Space.com.
For details on the DLR's work on rovers, crawlers & drones on Mars — the Valles Marineris Explorer project, visit the project's website.
