HERE COME THE AGRIDRONES
quadracopter (with four rotors),
of which there are many varieties.
Microdrones can be considered
a third category characterized by
diverse structures and theories of
operation, often using an insect
biomimicry approach.
Drones in the Fields
Airplanes have been used in
agriculture since shortly after the end
of World War I, when military biplanes
began to be converted into crop
dusters. Since then, crop dusting has
been the most iconic use of aircraft
for agricultural purposes. Despite
the success of full-sized crop dusters,
there are issues with them. They are
noisy, require skilled pilots and, if
not operated properly, they can waste
product by spraying it in the wrong
places. Airplanes fly fast and close to
the ground, which doesn’t leave much
room for error. And, nimble as they
are, even helicopters cannot get too
low over hilly, highly variable terrain.
Enter the drone age.
For crop dusting, rotary-winged
drones have a big advantage over fullsized aircraft because they can execute
slow, sharp turns and hover close to the
ground to provide tight coverage over
a given area. Small crop-dusting drones
can deliver pesticides or fertilizers accurately, but are not yet able to haul heavy
loads. In Japan, mid-sized, remotely
controlled helicopters have been spraying crops for years. These machines
do not fly autonomously yet, but their
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small size allows them to do jobs their
full-sized cousins cannot. A fleet of
small rotary-wing drones could make
short work of a large area if they work
in tandem. Groups of drones operating
this way are called swarms.
But what can drones do in fields
besides perform the role of crop
sprayer? Plenty, as it turns out.
Companies offering UAV services to
growers are proliferating. Some of the
features currently available in a typical outdoor system include automatic
takeoff and landing, automatic return
home, GPS navigation, way point programming (specifying the points where
turns are executed to fly a route), terrain following (useful in hilly terrain),
time-lapse photography and video (live
and recorded). Small UAVs are also
capable of using a variety of sensor
packages for map making, erosion
monitoring, infrared analysis of chlorophyll and other analyses. Since drones
can fly low, their cameras get unobstructed views that cannot be obtained
any other way. Drones are relatively
cheap to fly since they are so small and
light. Many are electric, so they can be
flown often to generate enough data
to get a detailed picture of the progression of a crop over time.
Indoor Agridrones
Although the term drone conjures
up images ranging from little quadracopters fabricated using 3D printers,
to weaponized military machines,
one doesn’t usually associate them
Most drones
have pilots on the
ground, and many
can also operate
independently of their
human masters.”
with indoor use. As it turns out, UAVs
may indeed have applications in the
enclosed space of a greenhouse or
other agricultural facility.
To work in confined spaces, a UAV
must be small. While they are getting
smarter all the time, drones are getting
more compact as well. One area of
active research when it comes to small
aerial vehicles involves swarms. A swarm
is a group of UAVs flying together
in a coordinated pattern. Individual
machines are aware of the positions,
velocities and directions of other
members of the swarm. Researchers
at the University of Pennsylvania
have demonstrated a swarm of three
agricultural UAVs. Larger swarms of
small UAVs could quickly inspect a
large greenhouse crop.
Even without the need for swarms,
miniature UAVs can still be useful.