Scout Rover

Despite recent technical advances, traversing rough terrain is still a challenging task for most mobile robots. On-Earth applications mostly focus on search & rescue scenarios, characterized by highly unstructured environment such as collapsed buildings or similar terrain. A common solution in robotics is the use of legged locomotion systems. However, these agile systems pose the disadvantage of high complexity and even higher demands on computation power. Especially in planetary exploration, these disadvantages pose a red line due to the high number of single points of failure which might lead to the total loss of the system.

In future missions the Scout rover will explore extraterrestrial lava tubes in future planetary exploration missions. (photo: DLR)

Hence DLR’s „Scout” rover uses a novel, compliant rimless wheel and compliant spine elements to overcome obstacles much larger than its wheels. Thereby it only requires one actuator per wheel. Utilizing the compliant elements enables an energy efficient, dynamic and even more important – robust – locomotion in even the hardest terrain.

It is the goal of Scout to explore places on foreign planets that were inaccessible to scientists so far: steep crater walls and caves. It is not only traversing hard, rocky terrain, but also „swims“ through extremely soft sands, in which normal wheeled rovers would fail. In order to finally explore caves on Mars and Moon, DLR works together with terrestrial speleologists very closely. As a matter of technology transfer the system may also be used in cave and mine rescue as well agricultural robotics.

Within the Institute of System Dynamics and Control, the system’s modularity also allows for verification of optimization and simulation-based rover development, as well as testing innovative control algorithms for electromobility on our own and „foreign planets”.

The Scout rover during a test campaign in the new planetary exploration testbed at DLR Oberpfaffenhofen (photo: DLR)

System characteristics:

Lightweight design yielding a total mass of ~18 kg
>6 kg payload at >5,0 l payload volume
Locomotion based on compliant „rimless wheels”
Maximum speed ~1.7 m/s
Maximum height of obstacles >250mm

Robustness:

Survives drops of >1,5 m height
Fault-tolerant with respect to actuator and mechanical failures
Simple intelligent design: 6 actuators for 6 wheels
Upside down operation possible
Phase shifts of the wheel spokes inspired by bionic gaits

Efficiency

Battery runtime ~4 hours
Passive compliant elements store energy and actively use it for locomotion

Applications:

Exploration of caves on Mars and Moon
Search for extraterrestrial life in caves and evaluation of habitability
Transport of payload into hazardous areas
Search & Rescue
Scouting for larger rovers
Terrestrial Applications: Research, Search & Rescue, agricultural robotics, cave rescue

Additional Information:

https://lpsc2021.ipostersessions.com/default.aspx?s=8A-BF-3E-9C-8B-4F-FA-20-49-08-61-64-4E-BB-FD-E2#

https://www.db-thueringen.de/receive/dbt_mods_00033220

Mission sketch:

https://www.hou.usra.edu/meetings/lpsc2021/pdf/1443.pdf

Videos:

https://youtu.be/ajW1QBk44XQ

https://youtu.be/buo9ecraWhM

References:

A mission concept for lava tube exploration on mars and moon – the DLR Scout rover. R Lichtenheldt, E. Staudinger, S. Adeli, J.P.P. Vera, G. Giudice, M. Baqué; 52nd Lunar and planetary Science Conference, 2021

Kolusz, Adam (2020) System wykrywania przeszkód łazika Scout bazujący na stereoskopowej kamerze głębi Obstacle detection system for the Scout Rover based on depth stereo vision. Masterarbeit, AGH Krakau.

Lichtenheldt, Roy (2020) Towards exploration of future mining capabilities - terramechanics and robotic planetary exploration of lavatubes. KGK III - Space Mining Conference, Krakau, Polen

Wiesner, Manuel (2018) Design and Control of a planetary Exploration Scout for extreme Environments based on the rimless Wheel. Masterarbeit, Universität der Bundeswehr München.

Stubbig, Leon und Lichtenheldt, Roy und Becker, Felix und Zimmermann, Klaus (2017) Model-based development of a compliant locomotion system for a small scout rover. In: Ilmenau Scientific Colloquium 59 (www.db-thueringen.de), 59. ilmedia. 59th Ilmenau Scientific Colloquium, 11–15 September 2017, Ilmenau, Deutschland.

Contact

Dr. Roy Lichtenheldt
German Aerospace Center
Institute of System Dynamics and Control, Space Systems Dynamics
Oberpfaffenhofen-Wessling
Tel.: +49 8153 28-3095
Fax: +49 8153 28-44-3883