1. Abstract
Background
Design History
CAD Model versus Prototypes
Manufacturing Method
Previous Design
Acknowledgements
A kite-based system of capturing wind power would be advantageous because it provides an
inexpensive and accessible method of generating energy for laymen. By reducing weight and
complexity in generator systems, we hope to find this proof of concept successful in illustrating
the potential of consumer products in harnessing renewable natural resources. Pneumatic networks
are embedded into elastomeric materials, which can deform a great deal without significant
damage. These actuators, when inflated by a ground unit, adjust control surfaces that affect the
kite’s motion. A power transmission system is to be used to convert the energy of the kite’s motion
into electric current. Ultimately, the project was successful in reducing weight to facilitate flight.
Kite steering is not perfect yet, but is possible with these actuators. This research validates interest
in consumer power generation. At the moment, it requires much attention to yield little power. In
the future, this technology will be equipped with digital sensors in the steering system to better
regulate air pressure and kite motion. Hopefully, this innovation will improve the efficiency and
power output of this project.
References
Results & Conclusions
Future Directions
For each version of actuator created, a certain procedure was taken toward the manufacture
of the product:
1.Design the actuator and molds using SolidWorks computer aided design software.
2.Print each mold using the research lab’s 3D printing equipment.
3.Prepare the molds and fill them with liquid Ecoflex-30 or Moldstar-30 elastomers.
4.Degas the mixture in a vacuum chamber to remove bubbles and leave to cure.
5.Remove the parts from their respective molds and prepare them for combination.
6.Silpoxy the components together so that the pneumatic network is hermetically sealed.
7.Puncture the actuator to create an inlet for inflation.
8.Test the actuator with a syringe filled with air and observe inflation characteristics.
Static testing included the inflation of the actuators individually. Using a syringe, air is
injected into the actuators. Variations in inflation profiles were noticed. The ideal product
has consistent inflation from wide end to narrow end, but greater curvature at the wide end.
Two specimens were chosen to be mounted because they fit the desired profile.
The imperfect specimens were used to test adhesives to seal the port-tube interface. Semi-
cured Ecoflex (used in the past) would not adhere to plastic tubing. Quick-curing epoxy
effectively fused the Ecoflex actuator to the tube. Testing showed that the actuator inflates
at approximately 4 psi.
This method was then implemented on the two best actuators and they were then mounted
to the kite. The complete adhesion seen in the test, however, did not occur. Further testing
will be done to determine a consistent and effective manufacturing process.
Flight testing occurred, though only to confirm the actuators’ effectiveness in banking the
kite from side to side. The flaps wavered in alternate directions and tossed the kite. Liftoff
occurred in only 8 mph winds. This can be attributed to the overall reduction of weight of
the actuator by 42% (from 45g to 26g). Net lift can be increased with better actuator
mounting. If they are positioned in line with the kite’s center of gravity, kite tails and
ballast would not be necessary.
More testing will include three other setups: two actuators with flaps, four actuators with
flaps, and four actuators with webs. These variations allow for the configuring the kite for
best lift and control. Predictions currently indicate that the kite will be most maneuverable
when the actuators and flaps are wide on the kite.
With a working system of flight control, data can be taken in order to quantify flight
responses to various levels of inflation and wind conditions. Ultimately, a power-
generating system will be integrated and method of measuring the power output
implemented. This information can be compared with the power costs of compressing air
in the actuators to divulge whether or not this venture is as practical as it may be feasible.
For centuries, human civilization has been utilizing wind to power technology. Windmills were
interspersed in throughout the plains to grind the grain that grew around them. Today, wind
turbines are implemented to generate electricity. They reach toward the sky on metal stalks and
spin like pinwheels equipped with helicopter blades. This technology has become synonymous
with wind power productions, but there are other approaches to be explored.
By using kites and gliders, it is possible to reach the same height as a wind turbine's hub without
constructing a costly support manufacturing enormous, dangerous blades. Power generation can
occur on the ground, as can repairs. Groups in Europe have been able to prototype some large
projects that can produce up to 40 kilowatts but have a large base station. This is less than the
approximate 100 kilowatts produced by modern wind turbines, but may develop to produce more
power or cost less per kilowatt produced. These large kite systems use winching systems to control
kite steering and retractions.
The goal of this research is to develop a kite steering system directly controlled by pneumatic
actuators, inflatable devices that deform and deflect air when pressurized. These actuators are
made of elastomers, rubber-like materials that can be cast and molded easily. They are designed
with embedded pneumatic networks, built-in channels for the air to fill and expand. These soft
robotics have the potential to put wind power in the hands of laymen. They are inexpensive to
produce and mount onto an everyday delta kite. As the name suggests, they are also elastic and can
go through many cycles of inflation and deflation before failing. This is much less complicated
than a large winching system or a lofty tower reaching the clouds.
In this proof-of-concept research, the objective is to design, construct, and test a successful kite
steering system without weighing down the kite terribly. Previous research has met some success,
but also some challenges.
•Last year, researchers were just able to attain flight with the assistance of an ocean breeze. The
actuator pushes on a 3D-printed hinge to push a leading edge flap. The next design had to be
lighter.
•To remove the need for a heavy hinge, a chambered actuator was designed. It curls when inflat-
ed and has a flat bottom to mount the actuator to the kite and the flap. When manufacturing this,
a male-female mold was printed and filled with a liquid elastomer, Ecoflex-30. The actuator was
difficult to remove and had undesired cavities. Some of the walls were thin and, when coupled
with the cavities, were fragile.
•The manufacturing approach was hen altered to eliminate cavitation. The actuator was separated
into three geometries: an end wall, a ring, and an inner wall. These were produced on flat-laying
molds. The sections were then combined with Silpoxy, a silicone-based epoxy. Even with sup-
ports especially for bonding segments, the resulting actuator was difficult to construct and exces-
sive Silpoxy-ing added undesirable weight.
•The steering approach was then re-approached with an understanding of fluid mechanics. For in-
creasing and decreasing differential lift and drag forces. The kite was modeled with a linear actu-
ator controlling a linkage connected to a pivoting flap, incrementally changing the kite’s effective
area. A difference in area between the two sides causes roll about the kite’s spine.
•The current design is an altered design that had been used before. It is a trapezoidal actuator
with branching channels. It is manufactured on a flat mold to resolve some of the previous issues.
It was altered again to raise the central channel to reduce stress at the actuator’s seams and in-
crease area for adhesion. A build-in port also improves actuator-to-actuator uniformity.
Hobbs, A. “Outline 2.1” Rutgers University. Unpublished.
Ippolito, M. “Information Dossier”. Kite Gen Research. 12 April, 2011. <http://
kitegen.com/pdf/dossierkitegenen.pdf>.
Whitesides, G. “Pneumatic Networks for Soft Robotics that Actuate Rapidly.” Harvard
University. 10 Jan, 2014. <http://gmwgroup.harvard.edu/pubs/pdf/1209.pdf>.
Yeager, T. “Aerodynamics of Kites”. Purdue University. 11 May, 2011. <http://
ptrivedi.com/projects/kite_aerodynamics.pdf>.
I undertook a commitment to research in order to gain insight through experience. After
college, there will be various paths upon which I could embark: research, design, and
manufacturing. Without sampling each in some manner, I would be incapable in making an
educated decision regarding what I want to do in my career. I am grateful for this
educational experience, as it has given me exposure to the expectations, methods, and
atmosphere of research.
Thanks are due to the Aresty Research Center for introducing me to this opportunity. Todd
and the other RAs have been invaluable in the preparation for the presentation of this work.
Additional thanks to Dr. Mazzeo and Jingjin Xie for providing the opportunity, as well as
for the support of the entire research group.
Recognition is also due to David Talarico, Alexander Hobbs, and Caroline Razuk, who
preceded me on this project.
Figure 1: (A) A finished actuator with a plastic pressurization tube in its port in flat state
(B) A finished actuator inflated at about 3 psi, in its curled state
(C/D) A 3D model of the actuator, designed in SolidWorks 2010 shown in front
and orthonormal views to best illustrate design
Figure 2: (Left) First, chambered design for full casting from a male-female mold setup
(Right) Segment of the actuator, manufactured in three trays for combination
A B C
D