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U
nmanned aerial vehicles (UAVs),
commonly known as drones,
are just about everywhere you
look nowadays and are being used for
everything from film making to tracking
sharks on the NSW coast.
According to Juniper Research,
commercial drone sales are expected to
rise by 84% this year alone, with annual
sales approaching US$500 million.
And as the technology continues to
become cheaper, more robust and more
accessible, their usage seems set to
become even more widespread in an
ever increasing variety of scenarios.
One development that seems set to
broaden the scope of application for
drones is a 3D LiDAR (laser mapping
technology) payload named Hovermap
that has been developed by the CSIRO.
“Most UAV systems you buy off the
shelf rely on an expert pilot – there’s no
collision avoidance – so if the pilot does
the wrong thing the UAV is going to crash
into anything that’s nearby. We’ve been
trying to solve this problem by adding
stereo cameras, LiDAR systems and
radar to UAVs for many years, allowing
them to sense the world around them
in 3D and react to obstacles,” says
principle research scientist and leader
of the Robotic Systems Team in CSIRO’s
Data61 division, Dr Stefan Hrabar.
Hovermap differs from past efforts
because of its ability to use LiDAR to
simultaneously map its surroundings
while sensing its position in the 3D space
without the need for GPS.
“The technique is called Simultaneous
Localisation and Mapping (SLAM).
This allows anything that is carrying
a laser to use information generated
by that laser to build a map and at the
same time figure out where it is in that
map. So it’s localising and mapping
simultaneously, in real time – figuring
out where the obstacles are and
preventing the pilot from flying in to
things,” says Stefan.
While there are other UAV systems
that use LiDAR to sense or map the
environment, these systems rely on
GPS and inertial navigation systems
(INS) integration to estimate the position
and orientation of the LiDAR. This often
renders them incapable of flying indoors,
underground or close to structures that
interfere with GPS signals. But because
Hovermap uses SLAM technology, it is
able to operate effectively in these areas.
The system can be used in two
ways: one is to generate 3D maps and
take measurements using the LiDAR,
while the other is to carry out close-up
inspections using cameras and other
sensors by exploiting Hovermap’s ability
to safely fly close to structures.
“If you need the 3D structural
information to take measurements or
see if something’s moved, you use the
LiDAR map. But if you need to do a
visual inspection – if you’re looking
for small cracks or rust for example –
you’re not going to see that in the LiDAR,
there’s just not enough resolution in
the data. You need a camera on board,”
says Stefan.
Hovermap’s collision avoidance and
pilot assist modes are currently being
flight tested and will effectively reduce
the cognitive load on the pilot, allowing
them to focus more on the mission
than on piloting the UAV. The system
calculates the best flight speed and
optimal distances from structures when
undertaking mapping and inspection
tasks and ‘knows’ where it’s been,
ensuring no blind spots are created. This
EYES IN THE SKY
New developments in drone
technology are paving the way
for widespread adoption of the
machines across a range of
commercial applications.
Jacob Harris
explains.
The CSIRO has developed a 3D LiDAR payload that can simultaneously map its
surroundings while sensing its position in the 3D space.
TECH