The document discusses the implications of developments in unmanned aerial vehicles (UAVs) for the potential development of fully autonomous tractors. It outlines how modern tractors have some automated functions but still require an operator. Fully autonomous tractors that could operate continuously without human presence are described as the "holy grail" for the industry. The document contrasts the autonomous capabilities of modern military UAVs like the Predator and Global Hawk with the vision for autonomous tractors, which could perform agricultural field work continuously and be monitored by a small human team rather than requiring large support operations. Developments in UAV technologies are promising for autonomous tractors but the goals and operational models differ.

1. what IMPLICATIONS does the revolution of tHE UNMANNED AERIAL
VEHICLE have FOR THE development of the AUTONOMOUS TRACTOR?
Missing
persons
It has been said that the ‘holy
grail’ of the agricultural vehicle
industry is the development of the
truly autonomous tractor. Unlike a
modern tractor that has been set up
with GPS, automatic steering, and
computers and actuators to control its
various components and implements
during field work, an autonomous
model would operate entirely alone,
without a human occupant on board
to monitor or control its actions.
Without the human, there would
be no need for a cab and roll-over
protective structure to protect the
operator from the elements and
accidents. There would be no need
for expensive cab/seat suspension,
heater, air-conditioning or a stereo
system to keep a driver comfortable
and entertained. And there would be
no call for a steering wheel, pedals,
knobs, levers or switches. Also absent
would be gauges, dials and expensive
electronic displays.
If the remaining aspects of this
technological challenge can be
successfully achieved, we would be
left with a smart, stripped-down
machine all about the business of
ploughing, planting, tilling,
harvesting and transporting.
What remains would be a
machine faithful to its linguistic
roots in the 19th
century: the word
‘tractor’, after all, is derived from the
combination of the words ‘traction’
and ‘motor’. Our autonomous model
would have a motor of some type, for
sure, as well as large wheels or, more
likely, tracks for efficiently transferring
power to the ground. There would
also be a hitch system of some sort
for pulling and possible pushing,
along with auxiliary hydraulic and
electrical systems for transferring
power to attached components.
The autonomous tractor would
also have sensors, including cameras,
GPS and lasers to track its position
with a high degree of precision and
help it avoid unexpected obstacles,
including animals and people. And
finally, there would be highly robust
computers and programs so that the
machine would be ‘aware’ of what it
was doing, and accomplish its task
without running into things or
driving itself into a ditch.
With varying degrees of success,
numerous vehicle manufacturers
and university teams have worked
diligently on this challenge, most
particularly within the past 10 years.
Most of their efforts have resulted
in a demonstration-level machine
using a heavily instrumented tractor
that can still be driven manually if
needed. Such demonstration tractors
can often perform specific tasks such
as tilling or spraying. These tasks are
often the simplest that a tractor might
perform, but nonetheless, they have
proved challenging to automate.
It could be argued, however, that
the goal of developing an all-round
autonomous tractor is not beyond
the reach of the industrial vehicle
industry, especially considering what
has been accomplished recently by
the aerospace industry’s development
of unmanned aerial vehicles (UAVs).
Hundreds of UAVs are, or soon will
be, flying through the sky around the
5352 iVTInternational.com September 2011 iVTInternational.com September 2011
steven casey, ergonomic systems design AUTONOMOUS VEHICLES
XXXXXXXX: xxxxxxxxxxx
Equipped with a pod-
mounted infrared
imaging sensor,
the Altair UAV was
particularly useful
in aiding wildfire-
mapping efforts over
California in 2006
Image: NASA

2. world, travelling in three dimensions,
not just two, and autonomously
performing all manner of tasks just
as complicated – if not more so – than
those performed by a farm tractor.
So let’s review the characteristics
and capabilities of some successful
UAVs, contrast their capabilities
with one another, and add a little
speculation on what all this might
mean to the development of the
truly autonomous tractor.
Partial versus full automation
New-fangled technologies once
seen as unnecessary or frivolous can
ultimately prove to be well worth the
cost. For example, GPS technology
first made its mark in agriculture
with the development of steering
lightbars placed ahead of the driver
to help him steer more accurately
through the field. “Who,” it was
widely believed at the time, “could
not steer an ordinary tractor straight
after a few hours of practice?”
Although quite simple in nature,
lightbars ultimately proved to be
reasonably popular. Owners learned
that they could steer more precisely
with the aid of these devices – they
lessened crop damage and reduced
unnecessary overlap during tillage
and spraying.
Now they have been superseded
by autosteer and automatic control
of complex implement functions
based on GPS and crop position.
Sprayers can be programmed to turn
off and on automatically, implements
can be raised and lowered without
moving a finger, and pumps started
and stopped by the computer. The
job of the operator has changed
from that of a controller to that of a
planner, implementer and monitor.
The bottom line associated with
the use of GPS-based farm tractor
automation is that field work can
become considerably more accurate.
Autosteer systems, coupled with
automated controllers, can reduce
the typical pass-to-pass overlap of 8-
10% to near zero. This means 10%
less material applied to the field, 10%
less distance travelled, 10% less fuel
consumed, and 10% less of the
operator’s (and machine’s) time.
What remains, of course, is to
completely remove the operator from
the vehicle. Theoretically, at least, the
labour savings alone could make up
for the costs of the added technology,
especially once it has been perfected
and mass-produced. The economic
prospects become even better when
everything on a tractor associated
with the needs of a ride-along
operator (or monitor) is removed.
Such a machine could become more
fuel efficient, lighter in weight, and,
in some ways, even more versatile
than its manned counterpart.
MAIN IMAGE: Altair control
station
ABOVE: Portable control
trailer for the Predator
AUTONOMOUS VEHICLES
iVTInternational.com September 2011 55

3. UAVs and UASs
While a UAV may be ‘unmanned’,
the unmanned aerial system (UAS)
of which it is a part is not at all
autonomous. In fact, depending on
the complexity and function of the
UAV, the UAS may require not only
one ground operator but sometimes
many operators and many dozens
of support personnel. UAS missions
can include electronic attack, close
air support, defence suppression,
targeting, reconnaissance, aerial
refuelling and supply.
Most recently, high-altitude UAVs
with long dwell times have been
studied for their potential as remote
orbiting sensors in a ballistic missile
defence system, thereby extending
a monitored area well beyond the
reach of ground- or sea-based radars.
Two of the smaller UAVs are the
RQ-2 Pioneer and the RQ-7 Shadow.
Weighing 205kg and 4.3m in length,
the Pioneer was jointly developed
by the US and Israeli militaries.
It is launched by rocket assist
while shipboard, from a runway, or
by a catapult when a runway is not
available, and is retrieved with a net
(when shipboard) or with arresting
gear while on the ground. Its five-
hour flight time makes it useful for
reconnaissance missions and gunnery
spotting. Pioneers are controlled via
a ground-based pilot via video feed
and real-time line-of-sight datalink.
A ground- or ship-based pilot ‘flies’
the aircraft and is supported by
numerous launch, recovery and
other support personnel.
The USA phased out use of the
Pioneer in 2007, following it with the
RQ-7 Shadow. Like the Pioneer, it is
primarily used for reconnaissance.
In the US military, a Shadow platoon
typically consists of four air vehicles,
two ground control stations, and
supporting ground transport vehicles.
The latest version has a wingspan
of 6.1m and an endurance of nearly
nine hours. Also, based on high
accident rates during landings of the
simplistic Pioneer, it was fitted with
an automated landing system.
Perhaps the two most widely
known UAVs are General Atomics
Aeronautical’s Predator and Reaper.
The former, originally designed for
deployment in ‘moderate risk areas,
unsecured airspace, open ocean,
and bio- or chemical-contaminated
environments’, can fly autonomously
or via the commands of a ground-
based pilot connected via a direct
radio link or satellite hook-up. It
has a wingspan of 14.6m, a service
ceiling of 25,000ft, and endurance of
24 hours. It is this extended dwell
time that has made it a useful tool
across many military and civil
applications. Predators have been
used for earth science research,
surveying wildfires, and anti-piracy
patrols over the Indian Ocean.
Developed at its own expense,
General Atomics Aeronautical’s
follow-on to the Predator – the
appropriately named Reaper – is
essentially a more powerful, faster,
larger, and, if so fitted, armed version
of the Predator and can stay airborne
for up to 24 hours. It has a wingspan
of 20.12m and a maximum altitude
of 50,000ft. Like the Predator, it can
be flown by the ground-based pilot
via a direct radio link when within
line-of-sight, or, more commonly, by
a distant ground-based pilot linked
by satellite. The remote pilot can
take direct control of the craft via
joystick, but most commonly, it flies
itself based on a transmitted flight
AUTONOMOUS VEHICLES
main image: General
Atomics’ Euro Hawk – a
close relative of the Global
Hawk
ABOVE: Mission control
station for the Predator
iVTInternational.com September 2011 57

4. plan. It is typically launched by an
airport-based crew, with control then
handed to a mission team until it is
ready to land 24 hours later.
The main ground control station
consists of a pilot position, payload
operator position, mission planning
and communications station, data
exploitation position, and synthetic
aperture radar station. Multiple
crews are necessary due to the long
duration of flights. More than 400
Predators and Reapers have been
ordered around the world, including
the Altair, a climate- and marine-
monitoring variant flown by NASA.
But the current leader in UAVs is
Northrop Grumman’s RQ-4 Global
Hawk. This jet-powered craft looks a
bit like the venerable U-2 spy plane,
largely because its mission is broadly
similar. Indeed, the U-2 is being
retired, to be replaced by the RQ-4.
Controlled via satellite link from
a remote location, Global Hawk’s
flights are fully pre-programmed, but
a ground pilot can take control if
necessary. Autonomous flight control
systems and GPS control take-offs
and landings; the latter handled with
a line-of-sight datalink. Operations
are handled by a distant Mission
Control Element, often on the other
side of the planet. Global Hawk has
an operational ceiling of 65,000ft
and an endurance of 36 hours – but
though it may be unmanned, dozens,
if not hundreds, of individuals are
required to carry out each mission.
Yay or Nay?
Technologically impressive? Without
a doubt. Staggeringly expensive?
Unbelievably so! A hint of the future
for the autonomous tractor? In some
ways ‘Yes’ and in some ways ‘No’ –
see ‘Food for thought’ below.
In the ‘Yes’ column, there are a
number of aspects that may indeed
foretell the path forward. The first
is that what has been achieved was
basically thought next to impossible
just a few years ago. Global Hawk,
for example, can autonomously take
returning to the barn 24 hours after
it set out to spray hundreds of acres,
precisely navigating its own way, and
applying exactly the right amount of
material only where it is needed, day
and night. And it would perform with
exactly the same degree of precision
and speed at the end of its long day
as it did at the beginning.
A final promising pointer relates
to whether the job is ‘dull, dirty or
dangerous’, a phrase that has justified
the use of UAVs for many military
missions. The same could be said for
an autonomous tractor, especially
with regard to exposure to spraying
operations. Operating a tractor for a
long day can have intrinsic rewards
for some – but few who have had
the experience can deny the potential
for ‘dull and dirty’ as well. iVT
Food for thought?
Considering that the main point of the truly autonomous tractor
is to eliminate – or at least substantially reduce – the manpower
required to operate a tractor during repetitive field work, in this
regard the current world of UASs is not a very good model of
where autonomous agricultural or industrial vehicles might end
up. Modern UAVs such as Global Hawk represent a staggering
technological capability, but also require staggering levels of
manpower to operate and maintain the systems. These are
essentially military systems, developed with massive budgets
and deployed in all corners of the globe at great expense by
legions of highly skilled people.
One vision for agriculture is of a machine that has the operational autonomy of a craft such as Global Hawk, but
without the sizeable support staff and massive overheads. Once it has been fitted with its working implement or tool,
the autonomous tractor would find its way out to the field by itself, arrive at its assigned place of work, do its job for
hours on end, and continue the process around the clock or until it was in need of refuelling or human attention. The
absence of sunlight or the arrival of heavy fog wouldn’t slow it down. It would alert its human master if it had any
special needs or instructions, but would otherwise just go about its assigned task.
A second, but related vision, is of a fleet of such machines, all controlled by a small team of operators and
maintainers in a fixed location. Other than a few hours of maintenance and preparation each day, the autonomous
tractors would toil away in the field under the watchful eye of a human monitor. Combined, the machines and their
few human masters would accomplish far more work than a fleet of traditional tractors.
off, fly halfway around the world in
any weather (day or night), perform
a complex mission, land itself a day
and a half later and park at the end
of the taxiway, waiting for a tow to
the hanger. So it is perhaps not too
much of a stretch to envision a farm
tractor with equivalent, but more
down-to-earth, capabilities.
We can also tick the question of
endurance. UAVs have achieved such
success partially because of extensive
flight times, so it is easy to visualise
an autonomous agricultural vehicle
AUTONOMOUS VEHICLES
iVTInternational.com September 2011
left: The Global Hawk
is the ultimate in UAVs
NEXT ISSUE
So how would you
go about designing
a user interface for
an automated or
remotely operated
vehicle? Steve
Casey provides
some hints in our
forthcoming Off-
Highway Annual
58