fact not fiction. science not speculation. - high power media · austro engine’s aero solution...
TRANSCRIPT
Space systemsThe ExoMars autonomous mission
Ultralight rotary powerAustro Engine’s aero solution
Cable assemblyAdvanced wiring analysed
Autonomous miningWhat’s driving the technology?
Autopilot systemsLeading the way
Batteries and chargersDevelopments in portable power
USV technologyUnder the skin of surface craft
Delair-Tech DT18Flying beyond the line of sight
UST 04 : AUTUMN/FALL 2015
UK £15, USA $30, EUROPE e22
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
LAUNCH ISSUE : NOVEMBER 2014
UK £15, USA $30, EUROPE e22
Hirth’s two-stroke magicInside a hi-tech UAV powerplant
Real-time operating systemsAnalysing the development issues
Penguin UAV DossierSecrets of a record-breaking platform revealed
www.ust-media.comwww.unmannedsystemstechnology.com
01 UST Cover 2.indd 3 01/10/2014 20:53
Fact not fiction. Science not speculation.
2016 US$ media kit
Published by
Autopilot systemsLeading the way
Batteries and chargersDevelopments in portable power
USV technologyUnder the skin of surface craft
Delair-Tech DT18Flying beyond the line of sight
UST 04 : AUTUMN/FALL 2015
UK £15, USA $30, EUROPE e22
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
LAUNCH ISSUE : NOVEMBER 2014
UK £15, USA $30, EUROPE e22
Hirth’s two-stroke magicInside a hi-tech UAV powerplant
Real-time operating systemsAnalysing the development issues
Penguin UAV DossierSecrets of a record-breaking platform revealed
www.ust-media.comwww.unmannedsystemstechnology.com
01 UST Cover 2.indd 3 01/10/2014 20:53
www.highpowermedia.com
Platform one
The UST news section is focused on technologicaldevelopment. Business and politics are only covered in so far as they impact directly on engineering solutions. From the outset UST has established itself as a publication that deals in hard science.
UST insights
UST ‘Insights’ drill down into specific technological topicsand unmanned vehicle applications. Each issue will carry one insight on an application of unmanned systems – from the bottom of the oceans to the far reaches of outer space. We will cover all areas during the year, culminating in an overview of the latest tech trends at the end of the year. UST is dedicated to providing invaluable knowledge for engineers.
Unmanned vehicle dossiers
Each issue of UST contains a main ‘Dossier’ offering an incredibly detailed look at a high-profile unmanned vehicle project, revealing many secrets of the technology that are simply not reported anywhere else.
Engine dossiers
The world of unmanned systems has created new requirements for small internal combustion engines, to the extent that currently there is far from agreement as to the most appropriate technical solution. A host of different approaches are being exploited, from two-stroke to four-stroke, from jet fuel to gasoline and from Wankel rotary to reciprocating. Each of UST’s Engine Dossiers explores in depth one of the diverse innovative power plants at the forefront of today’s unmanned revolution.
UST is unique – launched in October 2014, UST is the first ever publication to focus entirely on providing independent coverage of the engineering at the heart of unmanned systems. Published bi-monthly in 2016, it probes today’s cutting-edge projects to provide in-depth research insights, using rigorous investigation backed by professional peer review and critical analysis.
The unmanned systems industry is projected to grow exponentially over the coming years. UST is an invaluable resource of actionable intelligence for engineers whilst also providing a targeted promotional platform for those with products and services of interest to them. If you want to seize more than your fair share of the fresh opportunities being created in this exciting sphere then UST is an absolute must.
LAUNCH ISSUE : NOVEMBER 2014
UK £15, USA $30, EUROPE e22
Hirth’s two-stroke magicInside a hi-tech UAV powerplant
Real-time operating systemsAnalysing the development issues
Penguin UAV DossierSecrets of a record-breaking platform revealed
www.ust-media.comwww.unmannedsystemstechnology.com
01 UST Cover 2.indd 3 01/10/2014 20:53
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
76
Solid hydrogen storage pellets and fuel
cell technology are set to significantly
increase the flight duration potential of
electric UAVs.
Consider, for example, AeroVironment’s
Raven RQ-11, a UAV widely used for
reconnaissance by the US military
and other operators worldwide. Hand
launched, it has a 1.37 m wingspan
and weighs just under 2 kg, carrying a
surveillance camera and motor powered
by a lithium-ion battery giving it an
endurance of 60-90 minutes. Replacing
the battery with a pellet-fed hydrogen fuel
cell promises to triple its endurance.
The pellets have been developed by
Cella Energy, which has been working
with systems integrator L2 Aerospace
to replace the battery in a Raven with a
How difficult is fuel flow measurement?
The answer clearly depends on the
required accuracy.
In internal combustion engine test cells,
fuel flow is traditionally measured with
an extremely high degree of accuracy
using a Coriolis-type meter. In the context
of a UAV though, that is impractical, not
only because of the weight of such a
meter but its size – which is as large as a
bathroom cabinet.
The challenge then is to develop an
alternative means of measurement that
is feasible within the confines of a small
UAV, without significantly affecting the
craft’s weight. After all, the whole point
of precise fuel measurement in this
context is to allow the craft to exploit the
maximum flying time it can obtain from
its fuel load. Clearly, that task is complex
and challenging.
UAV internal combustion engines
are typically small-displacement two-
strokes, sometimes using a carburettor
but more often nowadays equipped with
electronically controlled fuel injection,
under the command of an ECU. It is
quite normal for that ECU to incorporate
data logging and to send that data to
the operator; from the logging of injector
opening times, most systems will calculate
fuel consumption. That’s all well and good
but how accurate is such measurement?
far greater source of electrical power for
comparable weight. There is wide interest
in proving the technology for the growing
number of civilian and commercial
applications, as it can be applied to
all electric-powered unmanned craft.
To this end, Cella is part of a further
collaboration, co-funded by the UK’s
innovation agency, Innovate UK, to
develop a 200 W hydrogen system for a
larger unmanned marine survey aircraft
used by the Scottish Association for
Marine Science, with fuel cell integration
by Arcola Energy. A test flight is planned
by summer 2015.
Central to the concept is the use
of the pellets instead of a tank of
hydrogen to supply the fuel cell. Cella
Energy’s pellets are solid capsules
that combine ammonia borane and a
The answer depends on the approach
to it. Using sophisticated techniques,
ECU supplier Performance Electronics
has developed what it says is accurate
fuel flow measurement as a modestly
priced adjunct to its control systems.
Those systems are used in automotive
applications as well as internal
combustion-engined UAVs.
Performance Electronics does a lot of
work for OEMs and others, supplying
engine control components with
branding by the customer; however, it
also offers its own brand of ECU, a multi-
purpose unit that incorporates ignition
coil and injector drivers, offers other
outputs according to the specific version,
accepts readings from all necessary
engine sensors and has a diagnostics
capability via CAN together with data
acquisition. It can be mapped using a PC
in the normal manner.
UAV versions of this control unit – the
PE4 – use similar hardware and firmware
modules as automotive versions, and
similar tuning software. The PE4 is fully
configurable and adaptable to specific
applications. Performance Electronics
engineer Brian Lewis noted that, for
example, some UAV applications require
more thermocouples than others.
“We have a daughterboard that can
accommodate that and lots of other
custom requirements. We also offer
polymer, and which release hydrogen
gas when heated to 100 C. Whereas
hydrogen gas normally has to be
compressed and consequently stored
in a strong and hence heavy tank, the
pellets can be stored on the craft in an
easily replaceable cartridge at ambient
pressure and temperature.
The pellets are heated sequentially
throughout a mission as dictated by the
UAV’s electronic control system, so as to
provide a constant supply of hydrogen
from this wing structure location to the
fuel cell. Only a few per cent of the total
energy output of the fuel cell is needed to
heat the pellets. The net result is a system
that can match the weight of the normal
lithium-ion battery while promising
sufficient energy to keep the motor
running for up to three times longer.
options such as Mil-spec connectors.”
It is the UAV market that has driven
Performance Electronics’ development
of integral fuel flow measurement. “We
found that our UAV customers wanted
more accurate fuel consumption
calculation,” explained Lewis. “They
wanted to know how much fuel they are
using, so they can work out how long
they can continue to fly.”
Lewis also said that in its own right
fuel injector opening time as set by
the injector drivers within the ECU is
insufficient data from which to accurately
calculate consumption, even when
referenced to fuel pressure, engine speed
and the prevailing mapping. The injector
dynamics have to be understood, starting
with the calibration of each injector with
reference even to battery condition.
He noted that it often isn’t appreciated
that battery voltage compensation is a
vital aspect of injector driving. “The ECU
can only alter mass flow indirectly via the
injector open time, and if battery voltage
isn’t what it thinks it is then a required,
10% change in mass flow for example
might in reality be a 15% change.”
Thus it is that an appreciation of
actual injector dynamics is central
to Performance Electronics’ fuel flow
measurement, which can be incorporated
into closed-loop control of an engine run
by one of its units.
76
Mission-critical info for UST professionals
Platform one
The pros of pellets
Cella Energy scientists working on the hydrogen-powered Raven UAV
This new NW-44 multi-fuel UAV engine produced by Northwest UAV is using Performance Electronics’ ECU with fuel measurement technology
Power supply
Going with the flowFuel management
November 2014 | Unmanned Systems Technology Unmanned Systems Technology | November 2014
Platform one
4948
Danielson Aircraft Systems
(DAS) is part of the Groupe
Danielson organisation
based beside the Magny
Cours (former Grand Prix)
circuit in France, and well known in the
automotive world for its road engines.
Danielson has enormous depth of
experience of compression-ignition (CI)
engines, so popular with French car
manufacturers. That experience, and its
increasing involvement in aerospace,
led to the French military commissioning
it to develop a clean-sheet-of-paper
turbodiesel specifically for UAV use.
Following that commission DAS now
has a range of three Trident engines,
of which the initial inline three-cylinder
(I3) 100 TD2 customer unit is profiled
here. The director of DAS, Frederic
Hubschwerlen, says the Trident project
was specifically targeted at the UAV
market rather than general aviation.
The customer Trident was developed
as a complete package with all ancillaries
including the cooling system and
transmission through to the propeller. The
state-of-the-art 100 TD2 is a 1.1 litre I3 that
features two-stage turbo-supercharging
yet has a dry weight of only 70 kg. It
runs on regular diesel or heavy fuel
and exploits mechanical rather than
electronic injection to keep it free from
electromagnetic interference. Among its
innovations is a novel torque-smoothing
system to protect the transmission.
Everything for the project was designed
in-house at DAS, whose extensive
manufacturing capability meant that very
little component production had to be
outsourced. Although Groupe Danielson
has extensive CI experience, it didn’t
follow that the Trident engines had to
be turbodiesels; they could have been
spark ignition (SI) like many existing UAV
engines. The design team saw a number
of advantages from the use of CI.
Regardless of power level – and Trident
is catering for 100 to 180 bhp – the
top priority in the UAV market is flight
time. In this respect CI is theoretically
advantageous compared with SI, since it
is inherently more fuel-efficient. A higher
compression ratio and a lack of throttling
of the charge air are, on paper, the basis of
efficiency higher than that of a comparable
SI engine. The main inherent drawback of
a CI engine though is lack of valve overlap
to assist charging, but that is counteracted
by the use of turbo-supercharging.
The CI process does reduce the time
available for injection, but that isn’t such
an issue given a combination of forced
induction and a correspondingly reduced
engine speed. That in turn (due to the
relatively low crankshaft speed) implies
reduced frictional losses, while the
relatively high compression ratio and the
use of turbocharging imply high torque.
The only real downside is the structural
requirement caused by the associated
elevated cylinder pressures, which
can result in a weighty engine, but
Danielson’s expertise with in-house
aluminium and magnesium castings has
paid dividends here.
Although mechanically injected, the
Trident family exploits direct injection
into the combustion chamber, reflecting
state-of-the-art CI practice. Also, CI
lends itself to the use of heavy fuels:
kerosene (paraffin) based fuels are
widely used by armed forces. They are
less flammable than gasoline, and so
are better suited to CI rather than SI.
The exhaust temperature of a CI
engine is inherently lower than that of an
SI one due to a higher expansion ratio.
On top of that, the 100 TD2’s dual-stage
turbocharging system further reduces
the acoustic and thermal signatures of
the exhaust – important considerations
for many UAV operators. Most important
of all though is flight time, and
Hubschwerlen says the Tridents have
been measured by DAS to be 40% more
fuel-efficient than a UAV four-stroke SI
engine of the same power level.
He also reports that the Trident project
was a response to specific issues
encountered by the French military in
operating its UAVs, identified as fuel
injection problems, acoustic signature
concerns, rapid wear, complexity of
maintenance, high fuel consumption,
high total ownership cost and operational
risks. All of these were associated
with the existing propulsion system
the military used, which had not been
designed for requirements such as high-
altitude operation, extreme temperatures
and high operational availability.
Trident is designed to address those
issues, exploiting proven Danielson
technology in a package designed
specifically for UAV requirements, in
particular exploiting a range of fuel
chemistries. In general terms, kerosene-
based fuels ignite quicker than diesel,
calling for appropriate adjustment
Danielson Aircraft Systems Trident 100 TD2 turbodiesel | Dossier
Ian Bamsey investigates a state-of-the-art French turbodiesel that’s been created specifically for UAV use
Spring 2015 | Unmanned Systems Technology Unmanned Systems Technology | Spring 2015
Three-pronged attack
Cutaway of Danielson’s Trident, three-cylinder turbodieselCompact turbodiesel power – the Danielson Trident 100 TD2
The Trident project was a response to issues the French military had with operating its UAVs such as fuel injection problems and high total ownership costs
4544
Google’s acquisition of
Titan Aerospace and its
‘atmospheric satellite’
has placed more
emphasis on the power
requirements of autonomous vehicles.
The prospect of using such solar-
powered craft instead of a satellite to host
a wireless service to deliver the internet
to PCs and phones in areas without
data coverage presents some very real
engineering challenges.
An example of the challenges comes
from the 2.5 m wingspan Green Falcon
UAV developed at the Queensland
University of Technology in Australia. This
is powered by 28 monocrystalline solar
cells generating just 500 mW, but that
is enough to power its electric engine,
onboard cameras and sensors to track
the progress of bushfires.
Larger, High Altitude Long Endurance
(HALE) UAVs can use the increased
surface area of their wings to generate
more power from solar cells to run their
propulsion and payload systems – which,
when the payload is a cellular base
station, is a serious challenge that is still
in the research lab.
Titan, based in New Mexico, has
developed the Solara 50, which is 15.5 m
(54 ft) long with a wingspan of 50 m
and carries a payload of 32 kg (70 lb).
It is powered by 3000 solar cells across
the upper wing, elevator and horizontal
stabiliser to provide up to 7 kW, storing
any excess in lithium-ion batteries in
the wings. Lithium-sulphur rechargeable
batteries provide an energy density of
400 Wh/kg while normal lithium-polymer
batteries provide 200 Wh/kg
The combination of the solar cells and
the lithium-sulphur batteries provides
enough power to keep the UAV in the
air for months, say the designers, at a
cruising altitude of 20 km (65,000 ft) as
The third-party autopilot software in
the Solara 50 is modelled by Google
engineers in the Matlab and Simulink
development tools, with the ability to add
extensions to enhance the requirements
of a specific operation. This takes into
account the advantage that, by loitering
on-station or circling over an area at high
altitude, the system will have a line-of-sight
connection to provide the best possible
link without having to worry about multi-
path interference or any signal degradation
as it passes through floors and walls.
A base station could be designed to fit
into the Solara’s 32 kg payload, but since
the propulsion system is a 5.5 kW electric
motor, that would leave only 1.5 kW for
other activities. Reducing the weight and
increasing the efficiency of the motor so
that it uses less power would deliver more
power for communications. A larger version,
the Solara 60, will be 60 m (197 ft) across
with a boost to 8 kW of power from more
an airborne communications station,
and eventually up to five years flying at
65 mph. This speed is determined by
the average wind speed of just 15 mph
at that altitude, coupled with the lower
air density, which means the craft has to
travel three times faster than closer to the
ground to maintain its lift.
These capabilities appealed to Google,
which bought the company in April 2014
to be part of its Google X technology
r&d lab. Solara could potentially replace
the balloon-based systems that Google
has been testing out, but the power
generated from the cells is the crucial
engineering constraint.
The Solara 50 uses a third-party fixed-
wing autopilot that has been integrated
with a GPS navigation system to enable
it to fly, take off and land autonomously,
and alongside various onboard sensors
in the payload it also has high-speed
radio links for transmitting telemetry data
solar cells on its surface, and an increased
payload of up to 100 kg (250 lb).
The actual base station technology
is still to be determined, but it will need
to provide a balance between available
technology, the power available –
known as the power budget – and the
availability of PCs or phones to connect
to the internet. Mobile phones are
designed to receive signals down to
-135 dBm, but have limits on the
bandwidth they can support. Wi-fi is also
widely available on handsets and on
every laptop PC, and could be teamed
with access points on the ground to
provide local networks and reduce the
load on the base station.
Airborne base stations | Insight
Aiming for the high life
UAVs look set to take on a key role as communications base stations – once various engineering challenges have been overcome. Nick Flaherty reports
back to the ground station. The autopilot
software, which is used by other UAV
companies such as NVOS, in Virginia in
the US, handles airspeed, altitude, pitch,
roll, heading or turn rate, and includes an
‘autonomous loiter’ function. This allows
the aircraft to remain at a fixed altitude
and position, or to return to ‘home’ and
loiter. In loiter mode, the UAV faces into
the wind, drifts with it for a short distance
and then powers up to return to the loiter
location.
This is vital, as it maximises duration by
minimising the power required to remain
at a constant location. At no point does
it turn downwind, as this would result in
it having to expend too much energy to
compensate.
The autopilot also handles landing
consistently on a narrow runway, even
in a crosswind, by intelligently managing
landing pattern and glideslope to
minimise over- or undershoot.
The large arrays of solar cells on its 50 m wings and the tail are the key to powering the Solara 50
November 2014 | Unmanned Systems Technology Unmanned Systems Technology | November 2014
Wiring harnesses are the nerves of unmanned craft (Courtesy of St Cross Electronics)
3332
One of the core challenges
with an unmanned
system is the connectivity
needed inside the
vehicle which, given
the number and variety of sensors
and cameras being used in them,
brings with it an increased need for
communications and therefore power.
Also, instead of having a centralised
control cockpit laid out around a driver
or pilot, unmanned systems have a
much more distributed design, and this
is changing the way the cable harness
that supplies power and data around the
vehicle is designed and implemented.
This is a key element in the challenge
to reduce SWaP – Size, Weight and
Power – in unmanned systems. Less
weight means a longer range for UAVs
and driverless cars, while a smaller size
for the electronics means more space
for passengers or for larger batteries,
and the harness can take up a surprising
amount of weight.
There are many ways of delivering data
around an unmanned system. Traditional
harness designs use copper wires, but
optical fibres and even wireless links can
be used. Each of these technologies has
its challenges, but the fundamental issue
for all of them is the need to provide
power as well. Every sensor and actuator
in the vehicle needs power, and has to
deliver data back to a control unit, so the
traditional approach has been to provide
that power alongside the signals by using
separate copper cables.
In every unmanned systems market
the proliferation of sensors, telemetry and
comms – and their distribution around
the vehicle – severely restricts system
weight and size, so the lighter, smaller and
faster you can make the connectivity then
the better the platform is able to perform.
However, with new high-speed connection
protocols such as HDMI being used for
high-resolution cameras, the range of
connectivity requirements is continuously
growing. This gives the harness designer
and maker more challenges, and
highlights the separation between the
power and comms functions.
To build a harness, cables of different
thicknesses can be woven together
into a ribbon, with the thicker cables
delivering power and the thinner cables
carrying signals. The thousands of
cables required in a vehicle constitute
considerable weight and cost, however,
and while some harness makers are
starting to use aluminium rather than
copper to reduce the weight, there is also
a move to adopting different approaches
for connecting sensor units (see below).
Some unmanned systems are
able to challenge the existing design
methodologies. For example, having
solar panels on the wings and body
of a UAV allows power to be provided
closer to the sensors and actuators. This
removes the need for distributed power
cabling around the craft, potentially
reducing the complexity and weight of
the harness. However, the trade-off is
that more power management devices
have to be distributed around the craft.
This highlights the need for the harness
to be an integral part of the design of the
system, and for different architectures
to be assessed to provide the optimum
design with minimum weight.
Cabling There are various ways to build a
conventional harness, ranging from
bundling a set of wires together to
weaving them together. Cables have
been woven into ribbons for more than
45 years, but like everything else in the
modern world the harness has evolved
over that time.
At the moment, developers tend to
build a system and hang a harness
on it afterwards; going forward though,
harness makers will need to provide the
interconnectivity wherever it is needed
throughout the unmanned system. This
means that the design and project
managers can rethink wiring systems
away from conventional approaches and
integrate new methods (see below) into
their products that allow them to build
lighter systems with higher performance.
Very often the conventional harnesses
limit the design of an unmanned craft.
There are existing specifications and
conventions for the interconnections that
have been used for many years, and it
takes a brave engineer to adopt a new way
of implementing these connections instead
of something they’ve used for 20 years.
Now though, using wires as small
as 44 AWG allows a ribbon cable
only 9.5 mm wide to be built with 50
twisted pairs which provides substantial
signal connectivity. Many spacecraft
have these ribbons on either the flight
harnesses or in the instrumentation
packages and experiments.
A newer approach is to put these
ribbons inside a jacket or shell. One
application of this is to provide power for
de-icing the rotor blades of a helicopter,
and essentially these aren’t a harness
any more, but shaped components
accurate to +/- 1.00 mm with clamps and
pads built in and made from a 3D model.
This application is one of the harshest
environments an interconnection system
can work in.
The choice of shell or jacket materials
depends on the application, and typical
materials include polyurethane and
epoxy. It is possible to put 50 conductors
in a ribbon within a structure that’s 1 mm
thick and 19 mm wide; these are still built
as an add-on harness, but with UAVs in
particular the aim would be to lay the
ribbons into the airframe structure. Using
44 AWG wire to carry signals in the
Cable harnesses | Focus
Harness designs have traditionally used copper wires but optical fibres and even wireless links can be used. Each type though has its challenges
Summer 2015 | Unmanned Systems Technology Unmanned Systems Technology | Summer 2015
Well connectedHow do you serve an unmanned system’s need for power and signalling while keeping weight, space and cost to a minimum? Nick Flaherty reports
Weaving cables into a ribbon for a harness (Courtesy of Tekdata)
Space systemsThe ExoMars autonomous mission
Ultralight rotary powerAustro Engine’s aero solution
Cable assemblyAdvanced wiring analysed
Autonomous miningWhat’s driving the technology?
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
www.unmannedsystemstechnology.com
Focus articles
Revisited just once every 2-3 years the ‘Focus’ acts as an excellent source of reference on specific products and types of engineering service – topics covered include: • Additive Layer Manufacturing • Advanced Metals • Ancillary engine systems • Antenna systems • Autopilot/Flight controllers • Batteries • Cameras/imaging • Coatings • Composites • Connectors • Control systems • Data acquisition • Data storage • Electric motors • Fuel cells • GNSS • GPS • Ground control systems • Hardware • Motion control systems • Propellers • Radio links • RTOS • Sense & avoid • Sensors – electro optic/radar/acoustic • Simulation • Software • Solar power • Sonar/Acoustics • Telemetry • Test equipment • Test facilities • Training • Transmission • Transponders • UAV launch & recovery • Vision sensors • Wiring harnesses/cable assemblies.
Autopilot systemsLeading the way
Batteries and chargersDevelopments in portable power
USV technologyUnder the skin of surface craft
Delair-Tech DT18Flying beyond the line of sight
UST 04 : AUTUMN/FALL 2015
UK £15, USA $30, EUROPE e22
4544
Google’s acquisition of
Titan Aerospace and its
‘atmospheric satellite’
has placed more
emphasis on the power
requirements of autonomous vehicles.
The prospect of using such solar-
powered craft instead of a satellite to host
a wireless service to deliver the internet
to PCs and phones in areas without
data coverage presents some very real
engineering challenges.
An example of the challenges comes
from the 2.5 m wingspan Green Falcon
UAV developed at the Queensland
University of Technology in Australia. This
is powered by 28 monocrystalline solar
cells generating just 500 mW, but that
is enough to power its electric engine,
onboard cameras and sensors to track
the progress of bushfires.
Larger, High Altitude Long Endurance
(HALE) UAVs can use the increased
surface area of their wings to generate
more power from solar cells to run their
propulsion and payload systems – which,
when the payload is a cellular base
station, is a serious challenge that is still
in the research lab.
Titan, based in New Mexico, has
developed the Solara 50, which is 15.5 m
(54 ft) long with a wingspan of 50 m
and carries a payload of 32 kg (70 lb).
It is powered by 3000 solar cells across
the upper wing, elevator and horizontal
stabiliser to provide up to 7 kW, storing
any excess in lithium-ion batteries in
the wings. Lithium-sulphur rechargeable
batteries provide an energy density of
400 Wh/kg while normal lithium-polymer
batteries provide 200 Wh/kg
The combination of the solar cells and
the lithium-sulphur batteries provides
enough power to keep the UAV in the
air for months, say the designers, at a
cruising altitude of 20 km (65,000 ft) as
The third-party autopilot software in
the Solara 50 is modelled by Google
engineers in the Matlab and Simulink
development tools, with the ability to add
extensions to enhance the requirements
of a specific operation. This takes into
account the advantage that, by loitering
on-station or circling over an area at high
altitude, the system will have a line-of-sight
connection to provide the best possible
link without having to worry about multi-
path interference or any signal degradation
as it passes through floors and walls.
A base station could be designed to fit
into the Solara’s 32 kg payload, but since
the propulsion system is a 5.5 kW electric
motor, that would leave only 1.5 kW for
other activities. Reducing the weight and
increasing the efficiency of the motor so
that it uses less power would deliver more
power for communications. A larger version,
the Solara 60, will be 60 m (197 ft) across
with a boost to 8 kW of power from more
an airborne communications station,
and eventually up to five years flying at
65 mph. This speed is determined by
the average wind speed of just 15 mph
at that altitude, coupled with the lower
air density, which means the craft has to
travel three times faster than closer to the
ground to maintain its lift.
These capabilities appealed to Google,
which bought the company in April 2014
to be part of its Google X technology
r&d lab. Solara could potentially replace
the balloon-based systems that Google
has been testing out, but the power
generated from the cells is the crucial
engineering constraint.
The Solara 50 uses a third-party fixed-
wing autopilot that has been integrated
with a GPS navigation system to enable
it to fly, take off and land autonomously,
and alongside various onboard sensors
in the payload it also has high-speed
radio links for transmitting telemetry data
solar cells on its surface, and an increased
payload of up to 100 kg (250 lb).
The actual base station technology
is still to be determined, but it will need
to provide a balance between available
technology, the power available –
known as the power budget – and the
availability of PCs or phones to connect
to the internet. Mobile phones are
designed to receive signals down to
-135 dBm, but have limits on the
bandwidth they can support. Wi-fi is also
widely available on handsets and on
every laptop PC, and could be teamed
with access points on the ground to
provide local networks and reduce the
load on the base station.
Airborne base stations | Insight
Aiming for the high life
UAVs look set to take on a key role as communications base stations – once various engineering challenges have been overcome. Nick Flaherty reports
back to the ground station. The autopilot
software, which is used by other UAV
companies such as NVOS, in Virginia in
the US, handles airspeed, altitude, pitch,
roll, heading or turn rate, and includes an
‘autonomous loiter’ function. This allows
the aircraft to remain at a fixed altitude
and position, or to return to ‘home’ and
loiter. In loiter mode, the UAV faces into
the wind, drifts with it for a short distance
and then powers up to return to the loiter
location.
This is vital, as it maximises duration by
minimising the power required to remain
at a constant location. At no point does
it turn downwind, as this would result in
it having to expend too much energy to
compensate.
The autopilot also handles landing
consistently on a narrow runway, even
in a crosswind, by intelligently managing
landing pattern and glideslope to
minimise over- or undershoot.
The large arrays of solar cells on its 50 m wings and the tail are the key to powering the Solara 50
November 2014 | Unmanned Systems Technology Unmanned Systems Technology | November 2014
1918
Scion UAS, based near
Denver in Colorado and co-
located with sister company
Scion Aviation, is developing
a very special helicopter, the
SA-400 Jackal, which can accommodate
one person although they can opt not to
fly it themselves. In fact, that person can
be merely a passenger, with the craft
operating in fully autonomous mode.
Alternatively, it can fly without anyone on
board. Moreover, even flying unmanned,
it can operate from a ship, regardless of
the sea causing the deck to pitch, yaw
and heave.
The SA-400’s origins In 2012, Scion UAS responded to an offer
for tender by the United States Naval
Research Laboratory (NRL), calling for
an unmanned rotorcraft to be used in
its evaluation of specific payloads under
certain arduous conditions. For this
purpose the helicopter the company then
had under development, the SA-200
Weasel, with a length of 89.2 in (227 cm)
and a rotor diameter of 81.5 in (207 cm),
wouldn’t be large enough. More carrying
capability was called for.
The far more powerful SA-400 Jackal
that Scion offered for tender would
be a completely new project, and by
comparison would have a length of
232 in (589 cm) and a rotor diameter
of 250 in (635 cm). It would, however,
exploit the same advanced autonomous
operation technology initially developed
for the compact SA-200.
In the end the SA-400 proposal won
the NRL contract. That was at the end
of September 2012, and the deal was to
supply a pair of SA-400s with the option
for a third after satisfactory trials of the
prototype. In the light of this, the SA-200
project was put on the back burner,
just after its first ground tests had been
carried out, although Scion UAS CEO
Steen Mogensen emphasises that it will
be reactivated this summer, once the
NRL contract has been completed.
The fact that the SA-400 optionally
carries a person and that, if suitably
qualified, they can become its pilot
at the flick of a switch has been very
useful for development. Not only can
they concentrate on monitoring an
autonomous flight, their presence in the
cockpit means the FAA considers it as a
manned craft from the perspective of its
operational regulations, which are much
tougher for unmanned craft. Given that a
pilot is on board, there isn’t the restriction
on the use of commercial airspace
that there would be in the case of an
unmanned craft. The ability to ‘See and
Avoid’ is satisfied by the onboard pilot.
Currently the two initial SA-400s are
flying under an ‘Experimental’ FAA
classification. That is an airworthiness
certificate granted for a specific r&d craft,
accepting that there hasn’t been the
likes of crash testing but acknowledging
that there has been an FAA inspection
of it. Under an Experimental licence the
craft cannot be used for commercial
operations. It can be flown for r&d
purposes, initially within defined
geographic boundaries, but after a
certain number of hours have been
logged then anywhere nationwide.
The capabilities of the SA-400 without
a pilot on board were demonstrated
in September 2014. This exercise,
conducted in restricted airspace,
included autonomous take-off and
landing using a (truck-towed) mobile
platform. The first vehicle was delivered
to the NRL immediately after this
successful demonstration.
Flight trials of the second SA-400
began in early December 2014, the time
of UST’s visit, with delivery scheduled for
early 2015. Scion UAS is offering both
the SA-400 and the SA-200 on the open
market, and in due course it also plans
smaller as well as larger rotorcraft in its
product line-up.
The design briefThe SA-400 was designed to meet a
certain payload capability requirement of
the NRL but was not otherwise tailored
to a specific application; it is suitable for
multiple uses. The NRL requirement
was that it must be capable of carrying
a 100 lb payload for four hours’ flying
Ian Bamsey travels to Scion UAS in Colorado to get the low-down on a helicopter for which the pilot is optional, the SA-400 Jackal
Spring 2015 | Unmanned Systems Technology Unmanned Systems Technology | Spring 2015
Day of the Jackal
Scion UAS SA-400 optionally piloted helicopter | Dossier
Detail of the SA-400 during assembly, showing the tail rotor drive shaft, the main transmission, pulley with one-way clutch, dual alternators and main (Kevlar) drive belts
An SA-400 in flight – note optional side tank
6160
A composite is essentially
a material or structure
formed of two (possibly
more) distinct elements, the
principle being of course
to counter the disadvantages of the one
with the advantages of the other(s), and
vice versa. In unmanned systems, the
functional engineering objective is most
typically to achieve the best possible
mechanical properties for the least
weight, balanced against other factors
such as transparency to communication/
sensor frequencies, overall cost to
manufacture/maintain, and durability.
The use of composites to achieve these
objectives is a natural solution, as they
often provide superior specific properties
– that is, the strength or stiffness per unit
weight of material – compared to those
of non-composites.
The composites used in unmanned
vehicles can be divided into two basic
groups – metal matrix composites
(MMCs) or polymer matrix composites
(PMCs) – which are then reinforced with
fibres or particles of another material that
is typically more brittle but far stronger
and stiffer than the matrix. In such a
combination, the reinforcing material
carries the loading, while the softer matrix
serves to protect the fibres and transfer
the load effectively as well as holding the
required geometry.
Of the two, PMCs are more widely used
in unmanned systems, given their excellent
strength-to-weight properties and perhaps
easier manufacturing than MMCs.
often an epoxy resin. Pre-impregnated
woven fabrics or unidirectional tapes
(termed pre-preg) already contain
the matrix resin before lay-up into a
component, and the resins contain latent
hardeners that are activated by elevated
temperatures to fully cure the material.
The curing process cross-links molecules,
and this can be an exothermic reaction,
so care must be taken in controlling the
process temperatures, particularly in thick
components. To stop the resin curing at
room temperature, refrigerated storage is
required, and pre-preg composites have
a finite shelf life.
An alternative to epoxy resins is to
use cyanate ester-based resins, which
provide excellent high-frequency radio
wave transparency as well as very
low outgassing for space applications.
Outgassing is the release of trapped
molecules or gases from a material
placed in a vacuum – the gas can then
condense onto a satellite’s instruments
or optics for example. These resins can
also have a very high glass-transition
temperature (above 350 C) as well
as high toughness, making them
ideal for long-term service in extreme
environments. PEEK (polyether ether
ketone) is a particularly popular matrix
choice for hard-wearing functional parts
exposed to high temperatures, although it
is comparatively expensive.
Polymer compositesThe most popularly known PMC is of
course carbon fibre, or more properly
carbon fibre reinforced polymer (CFRP).
However, there are many alternative
reinforcing fibres available, and each
has its own advantages depending on
the application. The most commonly
available reinforcements besides carbon
fibres are aramid-based, glass, quartz or
thermoplastic fibres.
The carbon fibres themselves can be
manufactured from petroleum-derived
pitch as a base material, or more often
from a polyacrylonitrile (PAN) polymer.
PAN fibres are heated (oxidised and
carbonised) to burn off other elements
and leave the desired carbon, after which
further heat treatments can be applied to
ManufactureReinforcement fibres are handled as a
bundle, called a ‘tow’, of unidirectional
pre-aligned fibres, typically counted in
the tens of thousands (12K being 12,000
fibres per tow, for example).
A filament winding process forms
nominally cylindrical components
by winding a continuous tow of
reinforcement around a pre-form. The
tows used range from 1K to 50K fibres
and can be wound onto a mandrel in a
pattern to provide the desired properties,
typically useful for producing shafts or
pressure vessels.
Usually tows are woven to give a fabric
for lay-up in a mould. Spread-tow cloths
take each tow strip and weave them in
alternate directions to provide a cloth with
strength in more than one direction. The
particular benefit of spread-tow fabrics is
that the intersection between each weave
is very flat, so the fibres remain almost
straight, whereas more conventional
woven fabrics ‘crimp’ the fibres to a
greater degree where each weave
crosses over another.
Despite this crimping, the most
common form for composites is as a
woven fabric, with unidirectional tows
of fibres interlaced at 90o to each other,
giving bi-directional properties. Here,
each element of the weave is typically
much smaller than in spread-
influence the strength and stiffness of the
material as required.
Aramid fibres are based on an
aromatic polyamide, with a wide range
of materials more often known by trade
names such as Nomex (a meta-aramid)
or Kevlar (a para-aramid). Meta-aramid
fibres typically have high temperature
resistance, while para-aramid fibres
have excellent mechanical properties
for a given weight. Glass fibres may not
provide the same strength-to-weight
performance as carbon fibres, but they
are comparatively ductile and cheaper.
Quartz fibres are most often used for
housings such as radomes, given their
high-frequency radio wave transparency.
The reinforcement fibres are then
combined with a polymer matrix, most
6160
Matrix revolutions
Composites are a natural fit for unmanned systems, writes David Cooper, who explains how the materials are made and used
Composites | Focus
November 2014 | Unmanned Systems Technology Unmanned Systems Technology | November 2014
Spread-tow carbon fibre (Courtesy of TeXtreme)
UAV using thin-ply composites for airframe components
(Courtesy of NTPT)
1716
The ethos of the Penguin
unmanned aerial vehicle is
extreme endurance for civilian
applications such as pipeline
monitoring, mapping and
search and rescue missions. In 2013,
Professor David Schmale of Virginia Tech
was one of Popular Science magazine’s
‘Brilliant Ten’ for his work in tracking
dangerous microorganisms that surf
atmospheric waves; he uses a Penguin B
platform in that work.
A Penguin B has been used by
Centum to verify its new product
LifeSeeker, an innovative aerial on-
board system that can detect mobile
telephones belonging to missing people
and report their position to search units.
The Penguin B holds the world
endurance record for a UAV, set in 2012,
at 54.4 hours of non-stop flight. It was
the company’s first model following the
establishment of UAV Factory in 2009
by Latvian Konstantins Popiks. The
‘A’ version was a prototype that was
developed while Popiks was completing
a Masters degree in engineering at
Liverpool University in England.
Popiks admits that he found
development of the Penguin harder than
he imagined, as his only prior experience
was of building and flying radio-
controlled model aircraft. As a youth he
had been part of the Latvian national
team in competitions for radio-controlled
aircraft and rocket-launched gliders,
which he built himself. Design was trial
and error, he admits, while construction
used composite airframe technology,
albeit on a ‘build it at home’ basis.
Popiks notes that once he went to
Liverpool University he was able to take a
complete UAV using mostly in-house
components. Indeed, these days it can
supply the engine and the control and
launch systems, and all sub-assemblies
are available as individual components
that can be used with other UAVs.
Whereas the B is a platform that is
sold without a data link, autopilot or
payload and is tailored for each specific
application, the latest iteration – the
Penguin C – is a turnkey package.
With this model the customer only
has to confirm the required payload.
Whereas that lack of flexibility might be
a drawback in certain applications (and
more scientific approach to design, and
he pays tribute to the quality of the staff
on his course. Advanced software tools
rather than wind tunnel testing gave the
Penguin its aerodynamic form, which has
stood the test of time.
While still at the university he found
backing to set up an airframe production
company in Latvia. “I did the design
in Liverpool, while my colleagues in
Latvia did the fabrication,” he explains.
“I worked around the clock to help them
whenever I came back on vacation.” In
the end, “two-and-a-half” examples of
the Penguin A were built and flown as
prototypes, the ‘half’ being explained
by a number of crashes during this
experimental phase.
Having been established in its
current guise in 2009, UAV Factory
developed the Penguin B on the basis
the B remains on sale) it does allow
more complex packaging within the
same basic architecture. That in turn
allows additional features to be added. It
has, for example, provided the scope to
permit the development of a parachute
landing system.
Externally the Penguin C is identical to
the Penguin B, and uses the same wing,
booms and tailplane. While its fuselage
has the same outer form, internally it is far
more integrated. The same fuel-injected
engine and propeller are used but the
differences start with the engine mounts
and extend from there. Even the wiring
harness is different. At the time of writing,
the Penguin C was in testing prior to the
first customer deliveries in late 2014.
Penguin parameters In terms of size, clearly the lack of a
human operator on board allows a
UAV to be smaller than any manned
aircraft. Overall dimensions are then a
consideration of the size and weight of
the necessary propulsion system and a
compromise between payload-carrying
capacity and the adverse effect of
increasing platform area in terms of
UAV Factory Penguin C | Dossier
We had good aero and good composite work so we had confidence in the airframe and put it out at reasonable cost
A new-generation Penguin flies
Ian Bamsey visits UAV Factory in Latvia to discover the secrets of the remarkable Penguin C
A Penguin C on the end of a catapult – normally the payload is retracted for take-off
An exploded view of Penguin C identifying the main elements
of the experience of the A model and
manufacturing refinements such as
improved moulds. It supplied its first
customer in 2010, a competitor in the
Australian Outback Challenge. In this,
contestants have to locate a mannequin
in the desert in a mock-up search and
rescue mission using a UAV and, having
done so, supply it with a bottle of water.
UAV Factory started out selling just
a composite Penguin airframe, with
customers looking elsewhere for the
other components to produce a complete
aircraft. “We had good aero and good
composite work so we had confidence
in our airframe”, explains Popiks. “We put
it out at a reasonable cost – there was
nothing else like it on the market.”
Popiks says he recognised from the
beginning that a step-by-step approach
to developing the company would be
necessary. First came the airframe, then
an increasing number of subsystems
until UAV Factory could supply a
November 2014 | Unmanned Systems Technology Unmanned Systems Technology | November 2014
6968
All unmanned vehicles,
be they for use in
the air, on land or in
the sea, must carry a
transponder – effectively
a radio transmitter that provides details
of the vehicle’s identity, along with
other information such as its position,
speed, altitude or depth. The word itself
is a portmanteau of ‘transmitter’ and
‘responder’, which neatly describes the
device’s functions, and it can encompass
everything from commercial off-the-shelf
(COTS) equipment ready to be integrated
into a specific vehicle, to a highly
complex and bespoke design.
At their simplest, transponders provide
information. In essence, they receive
a radio-transmitted ‘question’ from an
unmanned vehicle control station or, in
the air domain, an air traffic control (ATC)
secondary surveillance radar (SSR),
which operates in the UHF section of the
radio spectrum. When the transponder
is interrogated in this way, it replies by
disclosing its identity and any further
information requested, such as its
position, speed and altitude.
SWaPDespite the differing tasks and operating
environments of unmanned air, land and
sea vehicles, their transponders share
common characteristics. For example,
they must have a reduced Size, Weight
and Power (SWaP) burden to ensure they
do not take up excessive space, which is
always at a premium no matter how large
the platform. Weight is also an important
consideration, since heavier transponders
can reduce a vehicle’s mobility.
Power consumption is the third
consideration. All unmanned vehicles
routinely carry optronics and radar
sensors, not to mention control systems
and in some cases weapons, all of which
place demands on power consumption,
so lower consumption frees up power for
other capabilities.
In addition to SWaP considerations,
unmanned vehicle transponders have to
guarantee immunity to electromagnetic
interference (EMI). This is a safeguard
to ensure that communications links
between the vehicle and the interrogator
are not lost in the event of a release
of EMI, whether it be from naturally
occurring meteorological phenomena
or as a result of the use of electronic
warfare (EW) techniques.
There is also the need to ensure
that the radio emissions from the
transponder, and the interrogations it
receives, do not interfere with other
onboard electronic subsystems. To this
end, the US Department of Defense
has several military standards (MIL-
STD) for various aspects of unmanned
vehicle transponder technology. These
include MIL-STD-461, which concerns
transponder immunity to EMI, and MIL-
STD-464 and MIL-STD-704 that cover
transponder compatibility with other
onboard power systems.
Transponders typically use the radio
spectrum, and in the case of UAVs this
can include the VHF and UHF segments,
in a range that stretches from 30 MHz
up to 3 GHz. Both VHF and UHF
transponders have a line-of-sight range,
but given that aircraft can fly at high
altitudes, UAV transponders can have a
range of several hundred nautical miles.
Where the link between the aircraft’s
transponder and the interrogator is not
blocked by the Earth’s horizon, ranges of
about 200 nautical miles (370 km) using
a line-of-sight link are possible. That
said, an over-the-horizon range of about
330 nm (just over 610 km) is possible
using radio relay techniques. Here,
another aircraft is positioned between the
operator on the ground and the aircraft’s
transponder to ‘bounce’ the signals
Transponders | Focus
Tom Withington explains the factors that need to borne in mind when designing these safety-critical devices
Summer 2015 | Unmanned Systems Technology Unmanned Systems Technology | Summer 2015
Personal details
There is a pressing need to ensure that unmanned aerial vehicles can fly safely alongside their manned counterparts in unsegregated airspace (Courtesy of USAF)
All transponders must have a reduced SWaP burden to ensure they do not take up excessive space, which is at a premium
An interrogator initiates requests for data from aircraft on their identity, position and so on. This example is used by the US Navy (Courtesy of BAE Systems)
Wiring harnesses are the nerves of unmanned craft (Courtesy of St Cross Electronics)
3332
One of the core challenges
with an unmanned
system is the connectivity
needed inside the
vehicle which, given
the number and variety of sensors
and cameras being used in them,
brings with it an increased need for
communications and therefore power.
Also, instead of having a centralised
control cockpit laid out around a driver
or pilot, unmanned systems have a
much more distributed design, and this
is changing the way the cable harness
that supplies power and data around the
vehicle is designed and implemented.
This is a key element in the challenge
to reduce SWaP – Size, Weight and
Power – in unmanned systems. Less
weight means a longer range for UAVs
and driverless cars, while a smaller size
for the electronics means more space
for passengers or for larger batteries,
and the harness can take up a surprising
amount of weight.
There are many ways of delivering data
around an unmanned system. Traditional
harness designs use copper wires, but
optical fibres and even wireless links can
be used. Each of these technologies has
its challenges, but the fundamental issue
for all of them is the need to provide
power as well. Every sensor and actuator
in the vehicle needs power, and has to
deliver data back to a control unit, so the
traditional approach has been to provide
that power alongside the signals by using
separate copper cables.
In every unmanned systems market
the proliferation of sensors, telemetry and
comms – and their distribution around
the vehicle – severely restricts system
weight and size, so the lighter, smaller and
faster you can make the connectivity then
the better the platform is able to perform.
However, with new high-speed connection
protocols such as HDMI being used for
high-resolution cameras, the range of
connectivity requirements is continuously
growing. This gives the harness designer
and maker more challenges, and
highlights the separation between the
power and comms functions.
To build a harness, cables of different
thicknesses can be woven together
into a ribbon, with the thicker cables
delivering power and the thinner cables
carrying signals. The thousands of
cables required in a vehicle constitute
considerable weight and cost, however,
and while some harness makers are
starting to use aluminium rather than
copper to reduce the weight, there is also
a move to adopting different approaches
for connecting sensor units (see below).
Some unmanned systems are
able to challenge the existing design
methodologies. For example, having
solar panels on the wings and body
of a UAV allows power to be provided
closer to the sensors and actuators. This
removes the need for distributed power
cabling around the craft, potentially
reducing the complexity and weight of
the harness. However, the trade-off is
that more power management devices
have to be distributed around the craft.
This highlights the need for the harness
to be an integral part of the design of the
system, and for different architectures
to be assessed to provide the optimum
design with minimum weight.
Cabling There are various ways to build a
conventional harness, ranging from
bundling a set of wires together to
weaving them together. Cables have
been woven into ribbons for more than
45 years, but like everything else in the
modern world the harness has evolved
over that time.
At the moment, developers tend to
build a system and hang a harness
on it afterwards; going forward though,
harness makers will need to provide the
interconnectivity wherever it is needed
throughout the unmanned system. This
means that the design and project
managers can rethink wiring systems
away from conventional approaches and
integrate new methods (see below) into
their products that allow them to build
lighter systems with higher performance.
Very often the conventional harnesses
limit the design of an unmanned craft.
There are existing specifications and
conventions for the interconnections that
have been used for many years, and it
takes a brave engineer to adopt a new way
of implementing these connections instead
of something they’ve used for 20 years.
Now though, using wires as small
as 44 AWG allows a ribbon cable
only 9.5 mm wide to be built with 50
twisted pairs which provides substantial
signal connectivity. Many spacecraft
have these ribbons on either the flight
harnesses or in the instrumentation
packages and experiments.
A newer approach is to put these
ribbons inside a jacket or shell. One
application of this is to provide power for
de-icing the rotor blades of a helicopter,
and essentially these aren’t a harness
any more, but shaped components
accurate to +/- 1.00 mm with clamps and
pads built in and made from a 3D model.
This application is one of the harshest
environments an interconnection system
can work in.
The choice of shell or jacket materials
depends on the application, and typical
materials include polyurethane and
epoxy. It is possible to put 50 conductors
in a ribbon within a structure that’s 1 mm
thick and 19 mm wide; these are still built
as an add-on harness, but with UAVs in
particular the aim would be to lay the
ribbons into the airframe structure. Using
44 AWG wire to carry signals in the
Cable harnesses | Focus
Harness designs have traditionally used copper wires but optical fibres and even wireless links can be used. Each type though has its challenges
Summer 2015 | Unmanned Systems Technology Unmanned Systems Technology | Summer 2015
Well connectedHow do you serve an unmanned system’s need for power and signalling while keeping weight, space and cost to a minimum? Nick Flaherty reports
Weaving cables into a ribbon for a harness (Courtesy of Tekdata)
6968
Additive Manufacturing (AM)
is one of a number of
widely used terms which
refer to technologies that
manufacture components
on a layer-by-layer basis, typically direct
from digital models. While terms such
as 3D printing are more often used
in the wider media, it is important to
draw the distinction between that and
the manufacturing technologies used
industrially. Therefore this article will
focus on those technologies that show
a readiness for applications that have
rigorous engineering performance
requirements, such as those in the
aerospace industry.
AM technologies can be readily divided
into two groups: plastic and metallic.
Although some solutions are available
that allow ceramic materials to be used,
these are not generally mainstream.
Plastic AM There are three primary AM technologies
for making plastic components –
fused deposition modelling (FDM),
stereolithography (SLA) and selective
laser sintering (SLS). FDM uses a heated
extruder head to deposit plastic filaments
into a given shape, in a process often
likened to icing a cake. FDM machines
range from very low cost (sub-£1000)
‘home printers’ to high-end industrial
systems (more than £70,000) with
generally a corresponding difference
in quality, mechanical properties of the
deposited material and productivity.
The second technique, SLA,
consolidates material from a liquid
photopolymer resin contained in a build
vat; a UV wavelength laser then cures the
resin before submerging the cured layer
into the vat by one-layer thickness and
levelling the next layer of liquid resin over
the top, ready for the next cycle. SLS is
very similar in concept to SLA but instead
it uses a thermoplastic powder feedstock
and an infrared laser to sinter the powder
particles together.
Each technology has its own advantages
and disadvantages with respect to the
others, and choosing which is most suitable
depends largely on the manufacturing
requirement. For a one-off part, FDM is likely
to be the most economic, while for large
numbers of components, SLS can be very
cost-effective as it is the only technology
where multiple parts can be ‘nested’ or
stacked together in all three dimensions,
rather than being restricted to a footprint on
the build platform (as with FDM and SLA).
Although the design freedoms are
certainly greater compared to traditional
moulding processes, there is by no
means total design freedom – certain
manufacturing rules must still be
observed. For example, both FDM
and SLA require the use of supporting
structures to build any down-facing
surfaces below a critical angle relative
to the build substrate. These structures
must then be removed either by hand
or, for FDM processes where a soluble
support material has been used, by
dissolving them from around or inside
the final component. While SLS does
not require any supports (and so
perhaps provides the greatest design
freedom), thought must still be given to
the finishing of the rough semi-sintered
surface, removal of unsintered
Additive Manufacturing | Focus
Making components using an additive process is ideal for the unmanned systems industry. David Cooper explains what those processes are and how they work
Spring 2015 | Unmanned Systems Technology Unmanned Systems Technology | Spring 2015
It all adds up
Design freedoms allow new design approaches to improve part performance
(Courtesy of Concept Laser)
Bespoke instrument housing for satellite application (Courtesy of CRP)
Ian Bamsey Editorial DirectorIan Bamsey is a world renowned technology writer and editor. Over the past 25 years he has created publications covering the technology of
racecars and race engines and more recently he was one of the founders of Unmanned Systems Technology magazine.
Bamsey is now concentrating attention on the equally complex and innovative world of Unmanned Systems Technology. The same challenges of engineering efficiency are present here together with a lot more freedom for experimentation with alternative solutions.
Nick FlahertyTechnology EditorNick Flaherty is one of the world’s leading electronics technology journalists. He has been covering the latest developments in semiconductor,
embedded software and electronics technology for the last 25 years as a writer, editor, analyst and consultant.
His expertise is now applied to the unmanned systems market, where the technology is moving fast. He brings detailed technical knowledge, analysis and experience of hardware and software system development to deliver a unique insight into the challenges of this exciting, cutting edge market.
Content overview
Autopilot systemsLeading the way
Batteries and chargersDevelopments in portable power
USV technologyUnder the skin of surface craft
Delair-Tech DT18Flying beyond the line of sight
UST 04 : AUTUMN/FALL 2015
UK £15, USA $30, EUROPE e22
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
LAUNCH ISSUE : NOVEMBER 2014
UK £15, USA $30, EUROPE e22
Hirth’s two-stroke magicInside a hi-tech UAV powerplant
Real-time operating systemsAnalysing the development issues
Penguin UAV DossierSecrets of a record-breaking platform revealed
www.ust-media.comwww.unmannedsystemstechnology.com
01 UST Cover 2.indd 3 01/10/2014 20:53
UST 05December/January 2016
UST 06February/March 2016
UST 07April/May 2016
UST 08June/July 2016
Ed deadline: 20/11/15
Ad deadline: 02/12/15
Publication date: 04/01/16
Bonus distribution: The Bahrain AirshowThe Unmanned Systems Expo (TUS)SkyTech
Ed deadline: 22/01/16
Ad deadline: 05/02/16
Publication date: 22/02/16
Bonus distribution: AUVSI EuropeSmall Unmanned Systems Business ExpoUMEX
Ed deadline: 18/03/16
Ad deadline: 01/04/16
Publication date: 18/04/16
Bonus distribution: XPONENTIAL – AUVSI USANext Gen DronesICUAS
Ed deadline: 20/05/16
Ad deadline: 03/06/16
Publication date: 20/06/16
Bonus distribution: Farnborough International AirshowWorld Congress on Unmanned Systems Engineering
FOCUS 1: Sense & AvoidSense and avoid technologies are an integral element of autonomous control systems. This focus article will look at the different architectures and algorithms being developed for implementations across the full range of unmanned systems.
FOCUS 2: Fuel cellsFuel cells are fast emerging as a viable energy source for unmanned systems. Our focus will look at the latest developments in the different fuel cell technologies, from the conversion stacks to the fuel storage and supply. It will also look at the management of the output power for the wide range of unmanned platforms.
INSIGHT 1: Tech Trends 2015 / 2016
FOCUS 1: Navigation systemsOur Spring focus is on the latest navigation technologies, from GPS and GNSS to the design and implementation of inertial measurement units (IMU). This article will look at the challenges of size, weight and power combined with accuracy and reliability and how these systems can be integrated with unmanned control systems.
FOCUS 2: Antenna systemsCommunication is vital for all autonomous craft, and the antenna is a vital component of this capability. This article will look at the challenges of antenna design for unmanned systems, from long range and multi-frequency designs to mechanically and electronically steerable implementations.
INSIGHT 1: Unmanned Ground Vehicles (UGVs)
FOCUS 1: UAV launch & recoveryLaunching and recovering unmanned aircraft can present a considerable challenge. There is an engineering trade off in the complexity of control systems and the design of the launch and recovery systems to provide the optimum solution for different aerial platforms. Our focus article will look at the latest solutions on offer.
FOCUS 2: Electric motorsElectric motors are starting to become a key element of many unmanned systems. This article looks materials and design of electric motors for higher efficiency from different power sources, as well how the control of electric motors is changing the design of unmanned systems.
INSIGHT 1: Unmanned Underwater Vehicles (UUVs)
FOCUS 1: Ground control systemsThe control and monitoring of unmanned systems can require a link to a ground station. We’ll look at the latest developments that provide the performance and flexibility required by the operators. The feature will include coverage of the hardware and software, as well as the impact of cloud technology on system development.
FOCUS 2: Solar powerUsing solar power is an increasingly popular option for unmanned craft. This focus article will look at the latest solar cell technologies for high energy density, low weight applications, as well as the power management technology that supports the implementation of solar power.
INSIGHT 1: Unmanned Aerial Vehicles (UAVs)
www.highpowermedia.com
Space systemsThe ExoMars autonomous mission
Ultralight rotary powerAustro Engine’s aero solution
Cable assemblyAdvanced wiring analysed
Autonomous miningWhat’s driving the technology?
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
UST 2016 Publishing schedule overviewNo. Issue Ed deadline Ad deadline On sale Key features
05 Dec/Jan ’16 20th Nov 2nd Dec 4th Jan Insight: Tech Trends 15/16
Focus 1: Sense & Avoid
Focus 2: Fuel cells
06 Feb/Mar ’16 22nd Jan 5th Feb 22nd Feb Insight: UGVs
Focus 1: Navigation systems
Focus 2: Antenna systems
07 Apr/May ’16 18th March 1st April 18th April Insight: UUVs
Focus 1: UAV launch & recovery
Focus 2: Electric motors
08 Jun/Jul ’16 20th May 3rd June 20th June Insight: UAVs
Focus 1: Ground control systems
Focus 2: Solar power
09 Aug/Sept ’16 22nd July 5th Aug 22nd Aug Insight: USVs
Focus 1: Data storage
Focus 2: Simulation/Testing
10 Oct/Nov ’16 23rd Sept 7th Oct 24th Oct Insight: Space vehicles
Focus 1: Performance monitoring
Focus 2: Embedded computing
UST 09August/September 2016
UST 10October/November 2016
Ed deadline: 22/07/16
Ad deadline: 05/08/16
Publication date: 22/08/16
Bonus distribution: Commercial UAV Show AsiaCommercial UAV ExpoInterDroneUnmanned Global Systems (UGS)
Ed deadline: 23/09/16
Ad deadline: 07/10/16
Publication date: 24/10/16
Bonus distribution: Commercial UAV ShowUnmanned Systems CanadaUVID – Unmanned Vehicles Israel Defense
FOCUS 1: Data storageThere is a fundamental trade off between the need for data storage and the communications bandwidth available for unmanned systems. We’ll look at the latest technologies, from flash memory to magnetic media and the interface standards to access them. Bandwidth, reliability, scalability and management are all key factors to consider.
FOCUS 2: Simulation/TestingThe development of unmanned platforms can be accelerated and improved with the latest simulation and testing technologies. We’ll explore both hardware & software-in-the-loop (HIL & SIL) technologies that are optimised to reduce the cost of development and improve quality.
INSIGHT 1: Unmanned Surface Vehicles (USVs)
FOCUS 1: Performance monitoringOne of the key challenges and advantages of autonomous systems is to have them return to base for maintenance before a failure happens. This needs increasingly complex performance monitoring sensors and algorithms, and we’ll consider the different approaches to delivering the capability, from hardware to software and how this impacts on the overall system design.
FOCUS 2: Embedded computingMainstream computing platforms are increasingly able to provide the control of unmanned systems. We’ll explore elements ranging from the processor and memory technologies to how boards and systems are used for such platforms.
INSIGHT 1: Unmanned Space Vehicles
Forward features
www.unmannedsystemstechnology.com
Autopilot systemsLeading the way
Batteries and chargersDevelopments in portable power
USV technologyUnder the skin of surface craft
Delair-Tech DT18Flying beyond the line of sight
UST 04 : AUTUMN/FALL 2015
UK £15, USA $30, EUROPE e22
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
LAUNCH ISSUE : NOVEMBER 2014
UK £15, USA $30, EUROPE e22
Hirth’s two-stroke magicInside a hi-tech UAV powerplant
Real-time operating systemsAnalysing the development issues
Penguin UAV DossierSecrets of a record-breaking platform revealed
www.ust-media.comwww.unmannedsystemstechnology.com
01 UST Cover 2.indd 3 01/10/2014 20:53
www.highpowermedia.com
Where in the world
Readership
Unmanned Systems Technology magazine is read by engineers around the world actively working on developing technological solutions for unmanned vehicles and the systems that support them. Written by engineers, for engineers.
48%
21%
15%16%
USA UK
Rest of Europe Rest of World
Core circulation – individually mailed copies6,000Readership (average 3 readers per copy)18,000• Chief / Head / Lead / Principal Engineer (UAV, UGV, USV, UUV) • Aerospace Engineer • Airworthiness Engineer • Chief Scientist • Developers • Development Engineers • Director of Design • Electronic Design Engineers • Embedded Software Engineers• Head of Innovation • Lead Robotics Engineer • Materials Managers• Mechanical Engineers • Program Managers • Project Engineers• R&D Engineer • Robotics • Researcher • Senior UAV Technician • System Integration Engineers • Technicians • Technology Researcher • UAS Logistics Analyst • UAV / UAS Operator • UAV / UAS Pilot • UAV Specialist
Space systemsThe ExoMars autonomous mission
Ultralight rotary powerAustro Engine’s aero solution
Cable assemblyAdvanced wiring analysed
Autonomous miningWhat’s driving the technology?
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
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Half page $4370 $3930 $3710
Quarter page $2300 $2070 $1960
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Full pageTrim: W210mm x H297mm Bleed: W216mm x H303mm Type: W190mm x H277mm
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Half page (H) Type area: W190mm x H136mm
Quarter pageType area: W92.5mm x H136mm
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Alternatively we do offer a design service by arrangement, so if you would like us to help make an advertisement for you, or amend an existing ad, then please get in touch to discuss.
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www.unmannedsystemstechnology.com
Autopilot systemsLeading the way
Batteries and chargersDevelopments in portable power
USV technologyUnder the skin of surface craft
Delair-Tech DT18Flying beyond the line of sight
UST 04 : AUTUMN/FALL 2015
UK £15, USA $30, EUROPE e22
UST 02 : SPRING 2015
UK £15, USA $30, EUROPE e22
The all-seeing eyeState-of-the-art vision sensors for unmanned craft
Driverless 4WDMIRA’s autonomous Land Rover
Danielson dieselInside the new generation Scion
SA-400Autonomous helicopter technology
www.highpowermedia.comwww.unmannedsystemstechnology.com
LAUNCH ISSUE : NOVEMBER 2014
UK £15, USA $30, EUROPE e22
Hirth’s two-stroke magicInside a hi-tech UAV powerplant
Real-time operating systemsAnalysing the development issues
Penguin UAV DossierSecrets of a record-breaking platform revealed
www.ust-media.comwww.unmannedsystemstechnology.com
01 UST Cover 2.indd 3 01/10/2014 20:53
Fact not fiction. Science not speculation.
UST has quickly become the magazine to study in our team as there is a real focus on the engineering perspective.
Phillipp Volz, CEO, Volz Servos
The magazines are brilliant. We use our UAVs for 3D topographical surveying and have built our own in the past. UST helps us keep up to speed with the ever changing industry.Stephen McManmon, Senior Engineer, Shannon Valley Group
UST covers the unmanned industry from the perspective no other magazine does – from an engineering point of view. Articles dig deep to explore the technical aspects of unmanned vehicles, from the technology used to the manufacturing methods involved. This approach is of great interest for anyone who is involved in designing unmanned systems.
Rory Bauer, Sales Director, UAV Factory
I have enjoyed the issues to date for their technical insight and depth of coverage. It is very difficult to find articles that are both readable and technically satisfying – in my opinion you strike an excellent balance!
Grant Shipley, Engineer, GeoSpatial Innovations, Inc.
Contacts
Editorial enquiries Ian Bamsey – Editorial Director – [email protected]
Nick Flaherty – Technology Editor – [email protected]
Advertising enquiries Simon Moss – Publishing Director – [email protected]
Subscription & General enquiries Chris Perry – General Manager – [email protected]
All digital enquiries Caroline Rees – Online Advertising Director – [email protected]
High Power Media Ltd Whitfield House, Cheddar Road, Wedmore, Somerset, BS28 4EJ, UKTel: +44 (0)1934 713957 Fax: +44 (0)20 8497 2102 www.highpowermedia.com • www.ust-media.com