Adaptable Wheels for Exploration

The problem of marrying large-surface contact with unobtrusive wheels can be solved by recurring to adaptable designs. Adaptable designs may provide a solution as the conflicting requirements on wheels are fortunately dissociated in operation. E.g. small wheels are needed when the rover is stowed (but not necessarily when it moves), small steering radii are needed in cluttered terrain (but not in soft terrain), large contact surface is needed in soft terrain (where steering radii can be large). Therefore it is possible to envisage that wheels with the ability to switch among a discrete number of geometric configurations could provide optimal performance in a rather large range of operational situations.
To date at ESA there has not been any R&D into adaptable wheels. Past R&D proposals were dismissed with the assumption that adaptability introduced unaffordable complexity. However there has never been any serious effort to quantify the “penalty” of complexity and also to analyse whether the penalty is commensurate to the benefits in performance.
A rover placed on the Moon pole, which has unpredictable soil characteristics, needs top performance to accomplish its challenging mission. It is quite possible that adaptable wheels may provide the level of performance that the rover require and at the same time increased probability of succeeding.
The activity shall:
1. Perform a state of the art search into the previously published concepts of adaptable wheels and analyse them with respect to potential of use in lunar pole scenario
2. Define requirements for adaptable wheels in a lunar pole scenario with attention to the operational phase/physical environment where the individual requirements are applicable. Define test scenarios.
3. Perform a trade off of the concepts to select the one that best accommodate the requirements also in consideration of the means used to actuate the adaptation
4. Prototype a set of AWE wheels and a set of conventional rigid wheels fulfilling the same requirements
5. Comparatively test the 2 wheel sets on a rover platform in the test scenarios previously defined.
NTUA-CSL is subcontractor in the project.