Read over this system design note...
Daisy Project System Design
The Daisy project is an attempt to realize
competitive open source airborne wind energy generation.
Project Executive Summary
The Daisy project is part of the rapid AWE
development program by Roderick Read, Windswept and Interesting Limited.
AWE can power world energy demand many tens
of times over.This project is open
Shared open design led to obvious, organic
looking devices. Some biomimetics and derivatives of natural pumping organisms,
formed from engineering, environmental and business needs.
New materials have been mixed with ancient
technologies to change the scale of wind power.
The designs are massively scalable. AWE can
change our relationship with energy sourcing. Everybody is invited to participate in open
AWE forums, open development, open prototype testing and product development.
Roderick Read was brought up sailing,
windsurfing, surfing and kiting in a tight community on the windy, religious
and ancient Isle of Lewis.
- 1.A stable lifting kite, able to
weathercock, optimized for smooth relative lift
- 2.A Ram air driven kite ring
system spins transmitting torque through tethering
- 3.Ground anchoring appropriate to
lift, weather cocking, and torque power conversion
- 4.Electrical generation set
- 5.Electronic control set
Where possible use tension systems and
constrained mass of air for structural rigidity aloft. This reduces weight
requirements considerably and allows scaling.
Optimise for continual autonomous
operation, ease of handling, price to performance, power to weight, modularity,
marketability, safety, minimal environmental impact of power extraction.
Stay within FAA guidelines for AWES. Adhere
to advice of TACO1.0
Proprietary certified radar transceivers
and manual NOTAMS may provide additional cost and time restraints on
installations intended to operate over 60m AGL. This would be factored into
scaled system costing.
Automated layer interfacing and panel
detach and reattach systems could dramatically improve deployment of multi
layered ring sets and lift kite surfaces. Proposals have been openly discussed
ofthe desire for machine developments
to provide for the problem outlined in these scenarios thus prior art is
established in the field allowing open development unhindered by patents.
Membrane structural analysis and
certification requirements do not as yet exist for this system. FEA and CFD
Models of system strengths and weak points will help to optimise and suggest
where reinforcements may be needed to meet standards.
For this project will be done on Hackaday
Roderick Read, 15a Aiginish, Isle of Lewis,
HS2 0PB. MOB 07899057227 firstname.lastname@example.org
Springer Airborne Wind Energy book http://www.springer.com/energy/renewable+and+green+energy/book/978-3-642-39964-0
Yahoo airborne wind energy forum https://groups.yahoo.com/neo/groups/AirborneWindEnergy/info
- 2.Wind to Rotary
- 3.Rotary to Electrical
- 4.Tethering, Anchoring and
Open developments in “Mothra” single
paneled skin, arched loadpath lift kites by Dave Santos of Kitelab and Roderick
Read of Windswept and Interesting allow for very large lift structures and
arrays to be implemented. Mothra’s use multiple ground anchoring points for
safety. Mothra’s can be anchored on radial tracks for weather alignment. Mothra
power control is easily adjusted by foot anchor trimming and nose tether. A
simple version will be used for initial intended market scale device
prototyping and tests. Mothra kites can be flown with or without loading. Thus
Daisy rings can be hoisted into place when ready to be set. A Mothra can have
various configurations of lift application points, thus Daisy rings can be
arrayed to effectively fill the frontal area of the arch.
A narrower post and boom centric version is
proposed for initial weather cocking lift models. Wide systems as shown will be
applicable to small human movable beach installations.
Wind to Rotary
Very large ram air and inflated kites have
already proven successful up to and beyond 300sqm approx 2MW with simple kite
window position flight optimization of a single line kite from a ship. The
benefits of cross wind kite flight dynamics for stationary ground generation
devices are impossible to ignore. Rotary systems which keep the kite in the
downwind power zone are ideal. Tether drag is a serious problem for fast kite
energy conversion. A rotary system does well by avoiding tethering at the outer
tips of rotation.
To maintain all of the most desirable flying
and energy capture dynamics a ring system of kites was devised.We simplify the design to a parametric
algorithmic describing the kite system, whereby the relationship of the number
of kites per ring depends on the predicted speed of the foil being used and the
radius of rotation. Further parametric relationships describe such as the
layering evolution properties of subsequent rings, ring area to kite area
ratios, foil setting, tether routing, ring dynamic and panel cutting. Many
other system parameter inter relationships have been explored. Designing kites
specifically constructed to be faster and tethered from their dynamic root will
Where the lift line links to the rotary
set, we used a rollerblade wheel to join the systems in the prototype to good
Investigation shows alternative
configuration based on more rigid blades inflating their mount ring. Tip to tip
tethering as shown is unlikely.
Rotary to electrical
Initial prototype power extraction was
demonstrated by driving the kite set against a mountain bike wheel and braking
against a squealing disk brake.
For the initial “campsite and ecobuild”
scale generation systems we intend to adapt an off the shelf e-bicycle
regenerative braking system such as the Falco emotors Hxm2.0 .
The regeneration characteristics of the
synchronous motor can be easily programmed to adapt to the current driving
characteristics of the kite set by using the existing falco software interface.
An off the shelf inverter should be
supplied to compliment the battery system.
Larger scale grid tied systems have more stringent
generation control needs and are not a part of the scope of this project. This
integration of Daisy kite generator systems with grid systems will occur once a
lower levelised cost of energy is demonstrated.
Tethering, Anchoring and Weathercocking
Multi point tethering provides safety
through redundancy. The strength to weight ratio afforded by modern rope allows
us to build lightweight tethering systems over large spans. It is desirable
that failure of any component does not incur catastrophic system failure. This
failsafe redundancy design principle includes the tethering of any single
component. The Mothra arch and kite ring systems have incorporated this simple
design safety principle.
Driver kite tether drag can be reduced
dramatically by appropriate bridling, ring layering distance reduction, inter
layer tether setting point and appropriately doped tether selection. The goal
is basically making less tether move through less air for the same energy
As the wind moves so too should the whole
kite system. This includes the anchoring system.The current prototype has shown itself to be
capable of accepting 40deg wind shifts over the Daisy ring frontal surface
without total loss of rotation or kite collapse. On initial trials the
prototype demonstrated a single unattended inline lightweight parafoil sled
lift kite can maintain Daisy to wind over a 3 hour test. However (without
dropped base loop line backup) a single inline lift breaks the rule of
redundancy. A kite stabilized to the sides of its wind window is a safer and
steadier lifter, but the sides need able to weathercock. The weather cocking of
spread lift kite tethering needs to be done at a radius greater than the ring
kite tip radius. Several open solution proposals exist; ground belay sets set
by operators, ring rope and carriage/trolley anchor sets, car anchor sets, rail
anchoring, hex meshed lift kite upper ring weather cocking anchoring, hex
meshed valley upper ring weather cocking anchoring, turret balanced kite bar
booms wider than ring radius.
For the initial camp / ecobuild scale model
a simple spread anchored tethering of a Mothra like lift kite is proposed. This
model has proven effective already in prototype testing. Tested stabilising
results of our tethering system has been welcomed by open science group
In order to maintain inherent system safety
we decided to first prove the system without any onboard software necessary to
run. However software systems have been invaluable in design and will be
invaluable for the potential monitoring, control and communication benefits of
Grasshopper parametric algorithm 3d
development language was used to model many possible system configurations
before a likely looking prototype was chosen. Likely was based on years of kite
experience and feedback from the yahoo AWE forum.
To build the kite kite ring prototype, measurements
were first taken from 1.3m ram air kites, which had approx ¼ span (half of the
right hand side) removed. Once these sizes were set in grasshopper, the ring
chute was developed to fit 3 driver kites. The ring was then divided into
smaller parts in multiples of 3 until a neat pattern for bridling and kite
mounting was found … and also so that each panel of the ring could be cut from
a pattern able to fit on an A3 sheet of paper. Determination of the exact panel
shape required used the squish function in Rhino… not an exact surface 2 axis
bending tool… but good enough… it worked quite well I think.
machine vision systems are available for experimentation, as are track and
control software from TU Delft, other open source kite tracking is also available.
Their use has previously been tailored to optimization of kite trajectory in
kite yoyo generation systems. It was felt this approach may be too complex for
the simple needs of the Daisy system.
Useful electronics and software can be
applied to Kite sheeting power control feedback, Lift kite position monitoring
broadcasting and regulation, ensuring top and bottom rpm matching to avoid
hockled lines, extended and improved access to radio comms, Falco emotors
generator charging control and performance feedback, acoustic analysis of line
and bearing performance, inspection, safety lighting, lofted generation for
localized operations, weather
data, network broadcast availability, line tension data ... and more besides.
For this project I plan to use easily
accessible and replicable software platforms with reliable operating systems,
simple programming, stock open source wireless solutions… yes old android
phones will be repurposed to perform a lot of jobs.An old android phone with wifi tethering
makes any kite a valuable new tool in it’s own right. Free software (such as
RPMMeter) is available for rpm monitoring using either the accelerometer or the
proximity sensor. Giri software can tell you the speed of your gear wheels with
Software demands of heavy duty controls
such as would be used on a kite sheeting system with through axis relative
tensioning will again need to be made failsafe. This feature will not be
attempted in the camping ecobuild scale project. It is a feature very suited to
a post and universal joint mounted model.
3d system file models are available from http://kitepowercoop.org or emailing rod
Rod dot read at windswept-and-interesting
Assuming that the lift kite has a good 3G+
data signal, It is logical to use this as the chief means of accessing kite
data remotely. Software such as the “Wireless Tether For Root Users” app for
android combined with phone state monitoring software such as stealthgenie can
allow recycled phones to take on new uses.
The Falco emotors generator has a
proprietary dongle device for remote pc configuration. I think it’s Bluetooth .
I’ll explore this further.
File and Database
Assuming this device proves popular, it
would be best that people with sewing, design, kite, sales, installation and
other interests would be able to share in the project.
Details of possible partnerships for
delivering a distributed open network enterprise management solution are
currently being considered.
Lift kites can be extremely powerful and
are not to be toyed with. Thin lines under tension can cut like cheese wire or
give really bad friction burns. Special precautions must be taken to ensure
safe lift kite operations. Always have correct fitting protective clothing.
Operators should always have an emergency rope cutting device available. Never
leave a kite which is un doused or readied to launch. Stay upwind of kite
surfaces. Keep control lines neatly laid and obvious.
Once the lift kite is launched, prepare the
Daisy rings upper end to be hoisted up to flying position. Hold and lift the
handles fitted to the daisy generation wheel. Apply the Daisy brake. Hoist the
Daisy back end to flying height. If all of the driving kites are set and open
ready to drive, Release the brake. If some of the driving kites are collapsed
to the inside, slowly release the brake until you can reach the collapsed
driver kite, prime the driver kite (throw it outward) and when ready release
Section still to be completed
Hardware Detailed Design
Software Detailed Design
Internal Communications Detailed
Interface Detailed Design
SYSTEM INTEGRITY CONTROLS