ROOM
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Astronautics
obtained from simulations will be verified by the
performance of a single-wheel test and a particle
image velocimetry (PIV) test.
This initial stage of the project will help us to
define the best approach in the production of
innovative rover suspension and chassis concept
designs. Our aim is to provide potential design
concepts that enable the production of a rover
locomotive system capable of achieving a high
The term ‘high-speed’ describes velocities two
orders of magnitude greater than the operational
velocities of current rovers, which means an
operational speed greater than 1 m/second. Benefits
of a faster mobility include:
• Exploration, mapping and characterisation
of geological features located far from
the landing area, including exploration
of regions currently dismissed by today’s
planned lunar prospecting missions due to
low operational speeds
• A faster return from shadowed areas to the
polar highlands
• Gathering of critical information in less time
is vital for the assessment of the scientific
value of a given region and exploration-based
decision making processes.
From DEM to prototyping
The first step towards the design of an advanced
locomotive system is to understand the micro and
macro-mechanics of lunar regolith. In line with
our aim to follow a step-by-step process, we first
need to study the effects of increased traversing
velocities on the behaviour of lunar regolith,
i.e. the variation of its properties: deposition,
compaction, erosion, etc.
Understanding the implications and limitations
of traversing at different velocities is crucial for the
assessment of the overall performance of a rover
locomotive system. This initial study is encompassed
both within the fields of soil mechanics and lunar-
oriented terramechanics, in which the Space
Robotics Lab has been specialising in for more than
20 years [6, 7, 8, 9].
An initial objective is to improve current numerical
algorithms for the simulation of soil behaviour
and its interaction with the driving system. This is
being approached by investigating the capabilities
of Discrete Element Modelling (DEM) in simulating
the behaviour of regolith as compared to the results
obtained by other numerical techniques.
DEMmodels consider a physical discretisation
of the material, which allows for the simulation
of the motion of a group of particles colliding and
interacting with each other. This will provide us with
the much-needed information to better understand
the mechanics governing how a high-speed rover
will traverse the lunar surface.
Together with odometric measurements,
i.e., data on the change in position over time
obtained from motion sensors and environmental
mapping, the outcome of these numerical models
provides the basic input for the rover’s navigation,
localisation and control schemes. Results
SELENE TC images of
the interior of Shackleton
Crater on the Moon. The
upper left image is the
original view of the crater,
while the large and upper
right images are enhanced
pictures based on the
original. In the large
image, impact craters of
hundreds of metres in
diameter, located along
the crater rim, are marked
by arrows.
The front wheels of the
NASA’s Spirit rover
sunken in Martian soil on
mission Sol 2126.
JAXA/SELENE
NASA/JPL-Caltech
