A proposal for - Villanova University

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13 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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A proposal for



Fish
Cam




by


Adam Agalloco


Team Leader

Monica Stoka

Mark Trostel

Theodore Whalen




Submitted to



Department of Mechanical Engineering

Villanova University



November 25, 2003



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2
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1.


INTRODUCTION


Broadcast Sports is one of the
m
ost widely viewed for
m

of entertainment today. It encompasses
such a wide spectrum of viewers from all over the globe, and as with any business it is continually
expanding into new areas. One of the ways that broadcast sports attempts to attract more vie
wers is
to enhance the viewing experience; a direct way to do this is to come up with more exciting,
entertaining, and almost interactive camera angles that put the viewer right at the “heart of the
action.” The SkyCam, MobyCam, and DiveCam are great exam
ples of this; each system was
developed with regard to the viewing audience. These systems enhance the experience by providing
views

and angles

that are

simply impossible by any other means, even

by
the at
tending
audience
.
Fish
Cam does just this; it is a

system not so dissimilar
to

that of MobyCam, howeve
r where
MobyCam is limited, Fish
Cam is boundless.
Fish
Cam recognizes the limitations of the MobyCam
syste
m and eliminates them. The Fish
Cam system is capable of motion in all directions along all
axes,
making it a valuable resource for underwater sporting events. Our design team
will

establish

a
prototype design

for the Fish
Cam system wherein the system is remotely operated and can be
maneuvered in all directions in order to get the best angle for the v
iewing audience.

This report
includes information on similar existing systems, technical aspects and surrounding issues, a
breakdown of the general subsystems
, design configuration possibilities
, as well as a cost projection
and schedule of work

(includin
g tasks such as
research, system
analysis, fabrication, and testing
)
.


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3
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2.

BACKGROUND INFORMATI
ON AND STATE
-
OF
-
THE
-
ART


Since this a new concept in many ways we have focused our research on the basics
of

underwater
robotics.
T
he problems

that

this project

will have to address are

the power system, the control
system, underwater propulsion,

an

underwater camera,

buoyancy
issues
, and

finally
waterproofing
and safe
ty concerns
.


There are many underwater robots currently in existence; however none

of them

focu
s on the need in
broadcast sports or specifically for use as cameras for media

and spectator type situations
. We
intend to use these current robots as benchmarks for propulsion and control, while
consistently

focused on the
specific

application for this r
obot. We are including the surveillance a
spect

as a
future

application
, but realize that these applications would most likely require a larger more durable
robot for use in bay areas and in
the open ocean
.
[3]


The research done in this report will be brok
en up by its sources. First we will discuss the current
robots which relate to our project. Then we will discuss the web sources that contribute to our
brainstorming. Finally journals, patents, and books will be discussed which deal with the subjects of

underwater propulsion, camera’s and transmission of video.



Figure 1










Current existing underwater camera systems are the
MobyCam and the DiveCam (both developed my
Garrett Brown). DiveCam is a system which follows
a diver from the diving board

into the water. It
employs a series of pulleys and cable which travel
down a long waterproof tube to achieve this (see
figure 1). The operator releases the camera from the
top of the tube at the same time the diver jumps and
they fall simultaneously int
o the water. The
MobyCam system (see figure 2) follows a swimmer
along the floor of the pool allowing spectators a clear
view of what goes on under the water.[1,3]


DiveCam is similar to our project in that it is a camera
system that goes underwater, howe
ver its application
base is very limited. Our project is very closely
related to MobyCam in the sense that the MobyCam
system is actually submerged in the water (see figure
3), whereas DiveCam is in a sealed tube. MobyCam
however, is virtually a horizont
al DiveCam without
the tube. It uses pulleys and cables for motion. The
proposed system would allow for complete
unrestricted motion of a camera underwater and the system may be tethered or remotely operated.
The proposed design addresses the restrictio
ns inherent in both the MobyCam and DiveCam
designs.[1,3]


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-



Figure 2

Figure 3


Underwater exploration has and is a rapidly developing research area. Because humans are
incapable of remaining underwater for extended periods of time, we have looked to r
obots to assist
us. The development of the Autonomous Underwater Vehicle (AUV) has been a huge advance in
underwater research (see figures 4


5). These vehicles are self contained and controlled, and are
equipped with sensors for high
-
quality data colle
ction used in various applications. These vehicles
however are designed for great depths and thus are large and cumbersome. The proposed design
will employ very similar means of underwater motion, yet dramatically smaller in size. AUV’s
house all the eq
uipment that is part of the proposed design making them a significant source of
information.



Figure 4

Figure 5



Several other academic institutions have worked on robots that are made for the water. Among the
most interesting in one which mimics th
e actual motions of a fish. In the mid to late 1990’s, MIT
engineers completed the design of Charlie the Tuna. Charlie the Tuna is a robotic fish that was
designed after studying a bluefin tuna. Charlie the Tuna is four feet long, and contains 2,843 par
ts.
These parts included 40 ribs, a set of tendons, a segmented backbone that included vertebrae, and a
Lycra skin exterior. Charlie maneuvers by moving its tail back and forth. [2,4]






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Figure 6


One of the ways to encourage new designs and technolog
ies is to hold competitions. The
Association for Unmanned Vehicle Systems (AUVSI) and the U.S. Office of Naval Research
sponsors an annual Underwater Competition (see figure 7). This past year twelve different schools
entered the competition. Vehicles i
n the competition must complete a set mission to earn points that
will win the competition. These vehicles are however completely autonomous, or ‘smart’ vehicles in
that they are fitted with sensors that tell an onboard computer information such as depth,

speed,
direction, etc. The proposed design would incorporate mainly propulsion and buoyancy features that
are part of the AUV, however it will not be autonomous simply because we want the ability to be
able to tell it where to go and what to do.

Figure

7



Another possibility for the propulsion is a fish propulsion system, a system that mimics the natural
motion of a fish to move underwater. The Parallel Bellows Actuator (PBA) fin does exactly that;
this device uses its flexibility as a propulsive for
ce and acts similarly to a muscle tightening or, in the
case we are most interested in, a fish tail moving. By attaching a hydrofoil to the end of the PBA, a
fish tail type device would be attained. Achieving this motion, while difficult, is not impossib
le,
however there are other functions of a fish swimming which make this device more difficult to
fabricate. In addition to the tail as a thruster there must also be fins to stabilize the fish so that it
stays level. The shape of the fish also plays a la
rge part in how it moves in the water; the overall

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6
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shape has a lot to do with the moves. As seen in figure 8, different shaped fish swim in different
ways. The fish on the farthest right of the picture is the most efficient and most functional method
whi
ch could be done with PBA’s. [16]

Figure 8



Hobie Cat Co. developed a propulsion system used in kayaks that mimics a penguin’s propulsion
thru water. This particular system is powered by the passengers in the boat via foot pedals. The
system consists o
f “two semi
-
flexible fins that move from side to side in a circular motion.” Greg
Ketterman, vice president of engineering at Hobie Cat describes the system: “At the beginning of
each stroke, the fins twist and flex in such a way that they assume the shap
e of a propeller blade to
actually propel the kayak forward. It’s a motion that’s identical to that of a penguin flopping its
wings up and down to move itself forward.”


(from
Moves Like a Penguin

Article) [17]


The dynamics of a penguin’s swimming is mo
re specifically the motion of a penguin’s wings to
propel it thru the water. In comparison of penguins’ wings to other birds, a few factors must first be
taken into consideration. The penguin is a bird that has adapted itself and it strictly a land and s
ea
animal, with no flying capabilities. Its wings therefore have adapted as well, as instead of flying thru
air, the penguin uses its wings in the water. Sea water has a density that is 850 times that of air.
Therefore, given the same Reynolds number, t
he lift and drag forces would be four times as great in
sea water than they would be in air. This density difference of air to sea water also increases the
inertia of the wings. [18]


The buoyancy of a penguin’s body is directed upwards. The x direction
acceleration of a penguin is
generated in the upstroke of the wings. In the upstroke, the penguin is pushing itself further down
from the surface with respect to the y (vertical) direction. With respect to the mean diving path of
the penguin when submerg
ed, the body moves upwards during the down stroke and downwards
during the upstroke. Due to the physical characteristics of a penguins body, the acceleration is
created in x direction while the bird is pushing itself downwards (negative y direction). [18
]


We discovered patents to be an excellent source for references on what underwater camera’s are
being used for currently and which ideas are currently being used. These ideas deal primarily with
the encasement of the camera and how it is to be used whil
e underwater. T
hey primarily deal with
the
more direct problem of having a camera underwater, not on the back of a robot which will be the
case with ours. [5
-
7]


Currently there is also a device which deals with filming underwater nature having a boat pul
l a line

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which has an underwater camera system on it. This enables the boat to not disturb the surroundings
since it is not necessarily near the underwater life when the video is being taken. [8]


There were a few patents which dealt directly with how to
transmit video images back and forth
from the submersible to user. The Navy’s patent on using a buoy to transmit video from a
submersible to another source. In this case the buoy is tethered to the submersible or camera which
is transmitting live video.

[9]

Similarly a private company also had a unique patent on how to solve
this problem for control and live video feeds. It is based around a general way of controlling the
robot through radio and receivers. In this patent the submersible relays informa
tion to a buoy of
sorts around which relays the signals from land or from another source. In this system there are
satellites of sorts which are on the water and whose sole use is to relay information. The system
described deals more on the larger scale
but could also be adapted to a much smaller scale.

[10]


There were also patents that dealt with the propulsion and steering of submersibles, though
surprisingly not as many as we would have thought, or liked. Most likely this is because submarines
and su
bmersibles have been around for a long enough time that the original patents have run out.
Still there was one unique patent which dealt with a different way of steering a submarine. It
describes a submarine like propulsion system which contains thruster
s in unique positions, one is
located towards the front on the top of the body and two in the rear. The front thruster controls the
direction of the vehicle while the back primarily provide
s

the power. [11]


Many of the subjects discussed in this report t
hus far are fairly technical concepts which may or may
not help us in our design. The next portion of our report deals with more basic and simple concepts
which may be more useful for us in the long run.


If an object is completely immersed or floating on

the surface of a liquid, there is a force acting on it
due to liquid pressure. This forc
e is buoyancy. The device we are designing

will be submerged, so
buoyancy will factor into the design. “Archimedes Principle” will be used in calculating the
buoyan
cy force. “Archimedes Principle” states that the buoyancy force is equal to the weight

of the
liquid displaced
.

[12]



The buoyancy force will also be important to the stability of the

underwater camera
. The center of
buoyancy is the center of gravity o
f the displaced liquid. The location of the line of action of the
buoyancy force is what determines t
he stability. If the robot

tips to one side because of motion in the
water, the buoyant force should off
set the weight of the it
, which acts through the

center of gravity.
The offsetting force will right the
device

and hopeful
ly keep the camera steady. [13]


The
device we are building

will move through the water while holding a camera, so the theory of
propulsion is important. Propulsion is motion of a
body through a fluid, and it is based on Newton’s
Laws
of Motion. [14]

Newton’s Second Law states that the rate of change of momentum in any
direction is proportional to the force acting in that direction. Newton’s Third Law states that for
every reactio
n there is an equal and opposite reaction. The same principles that are used by a screw
for propelling a ship through water may be used to propel the [platform] through the pool. Gill
explains that this principle is based on imparting momentum to a mass
of fluid in such a way that the
reaction of the momentum causes
a propulsive force, or a thrust. [14]



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When a body is submerged under water, there are two forces that are acting upon it: the force of
weight of the body acting downwards and the force of buo
yancy acting upwards on the body. If
these forces are equal in magnitude, opposite in direction, and acting along the same line of action,
the body is in a state of equilibrium. If the center of gravity of the body is shifted in relation to the
center of

buoyancy, the state of equilibrium of the body would then be upset. With a shift of the
center of gravity such as this, the shift would cause a torque on the body due to the difference in
spacing and location of the buoyancy force in relation to the weig
ht component of the force. Thus
not only do the forces need to be taken into account in order to achieve neutral buoyancy, but the
centers of gravity and buoyancy too must be taken into account for a stable, underwater body. [15]


Underwater vehicles are
a great source of information for this project. AUV’s provide us a look at
all the systems and how they interact in situations not so unlike the ones in which our project will be
performing. Looking at existing underwater camera systems we understand the

restrictions in their
design and plan to eliminate them creating an entirely new underwater camera system. There are
many ways to provide motion for this system and we have looked at both propulsion by small
electric propeller, as well as motion used by
nature to propel fish and other wildlife through water.
The AUVSI competition enables us to view how various designs function underwater, and which
designs could be more effective than others for our specific application. The design and fabrication
of an

omni
-
directional underwater camera system is very much possible, this research has been a
great source of ideas and information that will aide us in our endeavour.


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3. PROBLEM STATEMEN
T AND DESIGN OBJECTI
VES


This report contains a Quality Function Deplo
yment (QFD) diagram which lays out the basic design
problems which we plan on tackling. It deals primarily with the parts of the design which we have
anticipated as challenges and where we anticipate the solutions will be found. Also in this report is
an

explanation of the QFD which outlines where the ideas for it came from. The report also includes
the Product Design Specifications which further explains the target consumer and market for the
project as well as the other requirements. An explanation of

this specification is also included.


3.1
Explanation of QFD


Based upon our research and our
discussions with the customer [21
] we were able to populate the
customer requirements of the QFD chart. We decided to include the most basic to the most detaile
d
design elements to include in this chart. The most basic elements are easy to be overlooked;
however they are some of the most important and crucial to the function of the design.


The numbers filling the chart were chosen based upon the strength of t
he relationship between a
customer requirement and the engineering characteristics of the design. The level of impact and
consequent consideration of each aspect in the design is represented by either a nine, a three, or a
one; nine indicates a high consi
deration, three is for moderate consideration, and one indicates low
consideration. Customer importance was based on a scale from one to five; five being the most
valuable feature to the customer. The QFD was made to accommodate the customer in all ways
possible. Not all of the engineering characteristics can be easily attributed to there’s requirements.
Among the more ambiguous are: the line feed clarity; included so that a gauge could be put on the
type of video feed we would receive back, the system
placement; which deals with the location of
the motors, and the user interface; which deals with the control system on whatever type of switches
we use.




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F
igure 9


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3.2
Product Design Specification


Product Title

Fishcam.


Purpose

To provide a vehicle th
at will enable a pan and tilt camera system to move and operate underwater.


New or Special Features

This product will be able to move in at least two directions in a plane parallel to the floor and follow
a swimmer near the surface. A control system of s
ome sort will be implemented so that the platform
and the camera will both have controls.


Competition

This product should be competitive with MobyCam and DiveCam in the areas of broadcast sports in
addition to improving on these by adding mobility. [1]


Intended Market

This product is intended to be used in broadcast sports specifically in swimming and diving events
where live video from underwater is desired. The market would expand because the current devices
are installed and cannot be moved from one

location to

another, where as ours would.[21
]


Need for Product

Currently, there are no devices for broadcast sports which can transmit live feed video from
underwater and that have any mobility other than that in two directions.


Relationship to Existing

Products Line

Currently an active relationship is being sought out with Garrett Cam and their devices.


Market Demand

The underwater vehicle market is unlike the typical product market. Presently, the DiveCam and the
MobyCam are used exclusively for the
Olympic Games. The Fishcam is expected to take over the
market for the MobyCam because it will not be constrained by a track and will be able to be moved
from pool to pool. Without the trouble of the installation and permanence of the MobyCam, the
market

for the Fishcam will be able to expand beyond the Olympics.

[1,21
]


Price

The price of this product will be quite high, but this is not a major concern. While the Fishcam will
cost more than its present competition, it will be a great improvement over th
e current underwater
camera vehicles. The benefits of the Fishcam will outweigh the high price, and the intended market
will pay for the broadcasting edge.


Functional Performance

Able to maneuver in an aquatic setting.

Provides a clear and steady view of

the sporting event of interest.



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Physical Requirements

As small as possible while being able to support the weight of the camera and maintain stability.

Transparent around camera to provide a clear, unobstructed view of the event being recorded.


Service
Environment

The Fishcam must stay watertight and stable at all required depths. The transparent portion of the
system must also remain unaffected by temperature, pressure, and humidity changes at these depths
to ensure a clear view.


Life
-
Cycle Issues

T
he Fishcam is intended to be used for hundreds of events. The exact life cannot be pinpointed
because it depends on many variables such as the materials chosen for the product and the length of
time the Fishcam is exposed to an underwater environment.


Human Factors

Easily controlled.

Quiet so as not to distract athletes.

Safe to coexist with the athletes in the water.


Corporate Constraints

Must be manufactured quickly to stay on schedule with the customer.


Legal Requirements

Must make sure not to viol
ate any patents of current products on the market.


Musts

Watertight to keep its contents safe

Mobile Underwater in at least the plane parallel to the floor of the pool

Carry a payload equal to the camera, batteries and whatever else is put on the device

D
C power in or
der to be safe in water [20
]

Negatively Buoyant [20
]

Give the camera an unobstructed view from any angle

Maintain stability so that the camera will not be swayed


Wants

Enough speed to follow a swimmer

Remote Control Device for piloting

Output

from the Video Feed

Able to go to a specified depth of operation

Power (Batteries) contained within the device

Silent


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3.3
Explanation

of PDS

While deciding on our project we were already looking into what we felt was going to be the market
and requiremen
ts for our project. The PDS was made from these initial ideas and from the
information gathered from our State of the Art report. The market for our project was the only facet
of the PDS which was not found in the QFD, which was an important source of in
formation for the
PDS. In order to evaluate the market we talked primarily with the customer who gave us an idea of
the requirements for our project.


By understanding the musts and wants of the project more understanding was gained as to what
needs to be

done. The QFD and the PDS will be invaluable to us as we design our device. We were
able to break our requirements up into three major categories, each with several underlying topics;
Structure which deals with the shape and how it relates to the functi
on; Motion which deals with
propulsion of the device and its mobility; and Input/Output which deals with the electrical portions
of our device. We are confident as a team that we will continue to develop our musts and needs as
we further understand the pr
oblem at hand, and will be able to meet these with appropriate actions
towards the completion of our device.


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4. PRELIMINARY DESI
GNS


This proposed system should have multiple degrees of freedom for the platform as well as a wide
range of rotation and uno
bstructed view for the incorporated camera. The current aim for this
camera system is to be able to keep up with and film and aver
age swimmer in a swimming pool[3
].


There are two design alternatives currently being considered to meet these goals. The fi
rst design
alternative is an underwater submarine camera. The underwater submarine camera will be tethered
to supply the power source as well at the cable feel to transmit a live feed of the video footage

being
filmed by the submarine[20
]. Several design

possibilities for a submarine are still being discussed
with respect to method of propulsion, size, and shape of the apparatus among other features.


The other design alternative being considered is an adaptation of the current “Sky Cam” system[1].
This
underwater Sky Cam would be both restrained and controlled by numerous cables attached to it.
This particular design, unlike the self
-
propelled submarine, would be “pulled” through the water by
the attached cables. This would be similar to the current “M
obyCam”, which is pulled thru the water
via cables however has limited movement as it is running along one axis on a track at the bottom of
the pool.



There are several concerns with regards to the design and function of this particular project. One o
f
these concerns is the field of view of the camera system. In order to create a design with the widest
field of view possible, most design possibilities discussed thus far include the idea of a small pan and
tilt camera lens that will be omni directional
. With this feature of the camera, the design would
require that there be a clear view to the outside in all directions in which the camera can rotate so
that it can film with an unobstructed view. This requires that there be a see thru surface surroundi
ng
this camera as well as no large system components blocking the view of the camera.


Given the present goals of filming a swimmer in a pool, the cameras range of view will be around to
the sides and up, with all major components being located under the
camera. The camera when in
the water will be operating under the swimmer and therefore have no need to view or film anything
below it. This concern remains the same for both the submarine as well as the underwater Sky Cam,
as both will function at a leve
l below the swimmer while filming.


Stability is another concern of the system. If filming a swimmer while the camera is underwater, it
must be able to maintain stability so that the camera will be able to focus on and stay on the
particular filming subje
ct. Both possible design systems currently being discussed will maintain a
low center of gravity. This will provide the particular system with the stability needed to
successfully film the subject.



Stability will not be as much of an issue in the und
erwater Sky Cam as it will be in the submarine.
In the case of the underwater Sky Cam, the system should still have a low center of gravity to help
maintain stability, but it will also have the various cables that are moving it that will be aid in
maintai
ning the stability.


For the submarine however, stability is a big issue because it has no outside system of control like
the underwater Sky Cam. The submarine is self
-
propelled and therefore must retain its stability on

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15
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its own. Along with maintaining
its own stability while moving in an underwater environment, to a
certain extent the submarine must be able to maintain a stability that will overcome any turbulence
within the water. Many of our possible designs do include a keel weight that makes this s
ystem
much more steady and stable.


The propulsion of the system is a major concern, especially if it is to maintain the speed of a
swimmer as stated by the design specifications. The current MobyCam is a camera that lays on a
track and has cables pulling

it along the bottom of the pool from one side to another. The current
SkyCam has cables that suspend and move it above the playing field[1]. The underwater SkyCam
would be very similar to the current SkyCam with respect to its motion; however it would b
e on the
bottom of the pool. If the underwater SkyCam was to be built positively buoyant, then it could float
up to get a closer view of the action of given slack within the cables. The cables would also be able
to pull the camera from one position under
water to another in the same manner that the SkyCam
functions.


Propulsion for the submarine would be much more complicated however. The submarine would be
self
-
propelled and therefore must maintain within its own system the ability to maneuver itself thr
u
the water. There are three methods of propulsion being considered, the first method being a
propeller. A propeller contains blades similar to a fan. By rapidly rotating these blades will displace
the surrounding fluid, in this case, water, giving the

submarine a thrust to move. A drawback to
propellers is the fact that they are stationary in their position. They can only give the submarine
thrust in one direction. They can be adapted to give thrust in multiple directions however by adding
“rudders”

to the rear of the propeller. With these vents the direction which the propellers are
displacing the water changes and therefore will chan
ge the motion of the submarine[22
].


Another alternative for propulsion is thrusters. Thrusters are very similar to

propellers in that they
too consist of blades that rotate to displace water and thus provide thrust. A thruster possesses the
ability to rotate and thus provide thrust in multiple directions. This is done because the thruster has
the ability to rotate,
and therefore change the direction whic
h the water is being displaced[22
].


Within the possibility of using a thruster for propulsion is another type of thruster. A tunnel thruster
is a thruster which has a tube shape. The tunnel thruster provides excell
ent propulsion and also has
the ability to provide equal propulsion in both the forward and rear direction, a feature not available
with t
he other methods of propulsion[22
].



The final alternative being considered is a pump. The pump would be similar to
a pump used on a
jet ski. The pump takes in water, and then shoots out a stream of water in order to provide the thrust.
Similar to the propeller, the pump is stationary and therefore provid
es limited direction of thrust[23
].


The payload of the system

is also a factor that must be considered. The system selected must be able
to maintain its own payload, which will be comprised of the camera as well as all other components
of the system. In the case of the underwater Sky Cam, the system would most lik
ely be designed to
be positively buoyant, and therefore the payload would be maintained by the buoyancy of the
system. The system would be stabilized by being held down by the attached cables used for its
motion. Also, the cables could easily be pulled w
ith enough force for the camera to rapidly move
from one position in the pool to the next.


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16
-


The submarine would mos
t likely be negatively buoyant[20
]. In a pool filming swimmers during an
event, in case of malfunction it would be safer for the system to s
ink instead of float. It would
slowly descend the pool to the bottom where it would sit until somebody retrieved it. If it were
positively buoyant a malfunction of the system would run the risk of injuring a swimmer who would
swim into it.


Given this ne
gatively buoyant design, the submarine would need to be able to support its weight
within the underwater environment. This issue goes back to the propulsion concept. The method
propulsion would also need to have a component in the vertical axis being abl
e to control the
elevation of the submarine within the pool. Also the propulsion would need to be strong enough to
successfully move the submarine at a respectable speed through the water, which was determined to
be the speed of a swimmer.


Mobility is al
so a major concern. Not only with the acceleration of the system but also with the
agility of it to turn and easily change directions. Several possibilities have are being discussed using
various combinations of the propulsion mechanisms.



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-

4.1
Possible
Design Configurations


Figure 10

This Omni
-
directional design includes six (6) fixed thrusters, camera positioned on top of body, and
weight in conical bottom section for stablility.


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18
-


Figure 11

This is basically a SkyCam system that is underwater; it inc
ludes all major components of the
existing SkyCam system and would be adapted for an underwater
environment.

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19
-


Figure 12

This system consist
s of three (3) thrusters (one ma
in thruster in the rear, and two additional thrusters
on either side of the body), th
e camera position is on top of the body between the side motors, and
the keel weight mounted under the body provides stability.










-

20
-


Figure 13

This option includes two fixed thrusters on the outside of the body, an interior ‘tunnel’ thruster, and
the
camera is directly above the keel weight.














-

21
-


Figure 14

This design is adapted from the existing MobyCam. It has five (5) thrusters (two on either side, two
vertical thrusters in the body, and one main thruster in the rear of the system), and th
e camera is
positioned above the keel weight.




With the added possibility of the underwater SkyCam design a new set the team has been faced with
a whole new set of decisions. All options are still being weighed and considered. Another big factor
in the

decision outside of the design considerations stated above is the idea of future progress. The
current design goals for this project, given the time period to complete the project, are for a mobile
underwater device for a swimming pool. The submarine de
sign would leave the possibility open for
adaptation if the camera were to be used in the future in patrolling other bodies of water such as
lakes and possibly even the ocean.


-

22
-

5. STATEMENT OF WOR
K AND DESIGN SCHEDUL
E


This report identifies the chose
n design for the underwater mobile camera system and the rationale
behind that decision. Also included is the schedule for the design of the system, an estimation of
man
-
hours for the project, and a material cost estimate for the project.


Of the five con
cepts for the underwater mobile camera system, the tunnel thruster design was
chosen. This decision was based on the wants and needs of the customer, Ed Dougherty, as well as
his
professional advice and input [24
]. The criteria used in the selection proc
ess are listed in th
e
decision matrix (Figure 15
, shown on the next page). The five concepts evaluated in the decision
matrix are:

1

An omni
-
directional design with six
fixed thrusters and a conical bottom for
stability.


2

An underwater SkyCam.


3

A
system with three thrusters (one in
the rear, two on the either side).


4

An interior tunnel thruster with two
fixed thrusters on the outside of the
body.


5

An adaptation of MobyCam with five
thrusters (one on each side, two vertical
thrusters in the
body, and one main
thruster in the rear).





-

23
-



Concept

Criterion

weight

1

2

3

4

5

watertight

10

1

1

1

1

1

mobility

10

1

1

1

1

1

carry payload

10

1

1

1

1

1

DC power

9

1

1

1

1

1

safety

10

1

0

1

1

1

negatively buoyant

8

1

0

1

1

1

unobstructed camera

view

10

1

1

1

1

1

stability

9

1

1

1

1

1

speed(swimmer)

7

1

1

1

1

1

remote control
device

for piloting

3

1

0

1

1

1

output from video
feed

3

1

1

1

1

1

able to go to

specified depth of

operation

6

1

0

1

1

1

self
-
contained
battery

2

1

0

1

1

0

silent

1

0

1

0

1

0

simplicity

8

0

1

1

1

0

Total +


13

10

14

15

12

Total
-


2

5

1

0

3

overall total



11

5

13

15

9

weighted total


97

77

105

106

95

Figure 15
: Decision Matrix


Concept four (shown in Figure 13
) was chosen primarily because of the advantages of

the interior
tunnel thruster. With the tunnel thruster, the proposed design can move in the forward and reverse
directions with the same amount of force. This is a very advantageous feature because the system is
being designed to follow swimmers in a po
ol. Without the need to turn around after each lap, the
camera can really keep up with the swimmer. Also, the tunnel thruster is quieter than the outboard
thrusters, which will cause less of a distractio
n to the athletes in the pool [24
].


The selected d
esign (Figure 13
) includes an interior tunnel thruster with a keel weight underneath for
stability. The camera will be located at the top of the system, inside the transparent dome. This
design also includes two fixed thrusters (one on each side) for tur
ning.


In order to create an underwater mobile camera system that satisfies the wants and needs of the

-

24
-

customer, a strict time schedule must be followed. This design involves a great deal of research and
analysis, but it is also critical that the time for

building prototypes and testing them is maximi
zed
[25
]. The following design tasks have been identified:

1.

Research the parts for the system.

2.

Research and decide on the shape of the system. One major source of information for a
practical shape and size wi
ll be discussions with a marine engineer recomme
nded by Ed
Dougherty [24
].

3.

Purchase and receive the parts.

4.

Drag analysis of the system.

5.

Power analysis of the system.

6.

Mobility analysis of the system.

7.

Stress analysis of the system.

8.

Build the prototype.

9.

Test
the devices.

10.

Final testing and fine
-
tuning of the system.


The ten design tasks listed above are major tasks that include several sub
-
tasks. These are all listed
on the Ga
ntt chart attached in
Figure 16
. Also included in the chart are the man
-
hours estim
ated for
completion of each task, and the team member(s) responsible for each task. In addition to the design
tasks, a mid
-
term progress report, a final written report, and an oral presentation must be done.
These three tasks are included in the Gantt ch
art as well. The total man
-
hours estimated for this
project is 338 hours. This was calculated assuming the following:


One hour per day of individual work is estimated for each group member. When this is added up,
the total individual hours are



Adam A
galloco



43 hours

Theodore Whalen



40 hours

Monica Stoka




44 hours

Mark Trostel




43 hours


“Entire Team” is a joint effort of three team members (not everyone will be able to work on the
project every day) for the allotted days, therefore 4 hours don
e by the entire team would mean 12
hours of work.


56 hours x 3 people =



168 hours

Total man
-
hours =



338 hours


-

25
-

Figure 3
: The Gantt Chart, CPM Chart with Critical Path Identified*

*Tasks indicated in red illustrate the path of critical tasks, normal t
asks are shown in blue, and milestones are represented by a small star.



-

26
-

5.1
Cost Estimate


The estimated cost for this d
e
sign is about $9,000. Figure 17

(below) shows the detailed cost
estimate.

Item

Unit Price

Units

Total Pr
ice

[26
]
Thrusters
-

Tecnadyne

$3,445.00

1EA

$3,445.00



$2,239.00

2EA

$4,478.00

[27
]
Power Source

$350.00

1LS

$350.00

[28
]
Hull
-

Bulk Material

$200.00

1LS

$200.00

[27
]
Payload Enclosure
-

Dome

$100.00

1EA

$100.00

[28
]
Wiring
-

Bulk

$0.24

100FT

$24.00

[
29
]
Payload
-

Camera

$300.00

1EA

$300.00

[30
]
Waterproofing
-

Sealer

$10.99

3EA

$32.97

[29
]
Fasteners

$60.00

1LS

$60.00











Total Estimated
Cost:

$9,065.97

Figure 17
: Cost Estimate*

*Unit prices were determined from the actual price listing from in
dividual companies or were
estimated based upon similar existing systems. Units are listed as: EA (each individual), LS (one
lump sum, for things hard to separate individually), and FT (per foot).


This table represents a very rough cost estimate for the
proposed design. Only the main, most
obvious items for this project are included here. Due to the intricacy of the system, it is impossible
to list all components at this stage of the design process. It should be noted that this is only a
preliminary co
st estimate; it can and will be revised several times as the specifics of the design
become known. Depending on the exact materials selected for the design and the thrusters used, the
price will change considerably. Also, there is a chance that the paylo
ad may be provided by the
customer, which would c
ut out the cost of the camera [24
].


The tunnel thruster design concept was chosen out of the five possibilities; however, the exact design
is still unknown. This will depend on the results of the research
and further conversations with Ed
Dougherty and his marine engineer contact. Ideally the underwater mobile camera system will
include the thrusters liste
d

in the cost analysis (Figure 17
). Because these thrusters are rather
expensive, it is understood th
at they might not be obtainable at this time, and other options are being
explored. Once the final design decisions are made, the cost estimate will be much more accurate.


-

27
-

6. REFERENCES


[1]Garrett Cam. Multiple portions of the site used

<
http://www.garrettcam.com/index.shtml

> [2003, 29 Sept]


[2] MIT. MIT's Robotic Fish Takes First Swim

<
http://web.mit.edu/newsoffice/nr/1995/43471.
html

> [2003, 29 Sept]


[3]Dougherty, Ed. August Design; Personal conversation, [2003, 25 Sept]


[4] MIT. MIT Ocean Engineering Testing Tank Biomimetics Project: RoboTuna

<
http://web.mit.e
du/towtank/www/tuna/robotuna.html

> [2003, 29 Sept]


[5] USP no. 6574429; Underwater camera having viewports bearing on viewfinder tunnel of frame;
Smith, Stephen J.; Baker, Craig A.; Stiehler, Wayne E.; Eastman Kodak Company; Filed Dec 21,
2001


[6] USP
no. 6574433; Underwater camera housing; Stuempfl, Frank; Filed June 8, 2001


[7] USP no. 6574435; Underwater camera housing having sealed pivotable shutter actuator and
method, Smith, Stephen J.; Stiehler, Wayne E. ; Baker, Craig A.; Eastman Kodak Company;

Filed
Dec 21, 2001


[8] USP no. 6262761; Submersible video viewing system; Zernov, Jeffrey P.; Capra, Anthony L.;
Nature Vision, Inc. Filed July 6, 2000


[9] USP no. 6525762; Wireless underwater video system; Mileski, Paul M.; Manstan, Roy R.; The
United
States of America as represented by the Secretary of the Navy, Filed July 5, 2002


[10] USP no. 5579285; Method and device for the monitoring and remote control of unmanned,
mobile underwater vehicles; Hubert, Thomas; Filed August 21, 1995


[11] USP no. 65
81537; Propulsion of underwater vehicles using differential and vectored thrust;
McBride, Mark W.; Archibald, Frank S.; The Penn State Research Foundation, March 1, 2001


[12]
-

Hicks, Tyler G., 2000, “Stability of a Vessel,” Handbook of Civil Engineering
Calculations,
McGraw
-
Hill, New York, pp. 6.6
-
6.7.


[13]
-

Fox, Robert W., and McDonald, Alan T., 1973, “Buoyancy and Stability,” Introduction to
Fluid Mechanics, John Wiley & Sons, Inc., New York, pp. 90
-
92.


[14]
Gill, Paul W., 1952, “Theory and Applicati
on of Jet Propulsion Engines,” Gas Turbines and Jet
Propulsion, U.S. Naval Institute, Annapolis, p. 2
-
1.


[15] Baz
, A., and Gumusel, L., 1996, “Optimum Design of a Buoyancy and Gravity
-
Driven
Underwater Robot”, Journal of Robotic Systems, volume 13, “n. 7”
, pages 461
-
473


-

28
-

[16] <
http://www.ece.eps.hw.ac.uk/Research/oceans/projects/flaps/describe.htm

> FLAPS, Various
articles used [2003 30, Sept]


[17] DeGaspari, J., 2001
, “Moves Like A Penguin”, Mechanical Engineering, volume 123, “issue
number 4”, page 12


[18] Johansson, L.C., and Wetterholm Aldrin, B.S., 2002, “Kinematics of diving Atlantic puffins
(
Fratercula arctica

L.): evidence for an active upstroke”, The Journa
l of Experimental Biology,
volume 205, “issue number 3”, pages 371


378


[19] <
http://www.auvsi.org/competitions/water.cfm

> AUVSI, Cornell AUV Swims to First Place
Finish [2003 30, Sept]


[20]

Santhanam, Sridhar. Villanova University; Personal Conversation [2003, 2 Oct]


[21] D
ougherty, Ed. August Design; Personal conversation, [2003, 25 Sept]


[22]

<
http://www.tecnadyne.com/products.htm
>
T
ecnadyne Product Line, Various sections used
[2003 29, Oct]



[23
]
<
http://www.rule
-
industries.com/prodIn
foApp/servlet/DisplayProducts?typeId=RNABP&page=0&catalogId=Marine
&categoryId=BILGE&companyId=RULE
> ITT Industries


RULE, Various sectons used
[2003 29,
Oct]


[24] D
ougherty, Ed. August Design; Personal conversation, [2003,
5 Nov
]


[25] Santhanam, Sridha
r. Villanova University; Personal Conversation [2003, 6 Nov]


[26
]

Chapman
, Michael
.
Mecco, Inc.
;
Email Communication
, [2003,
11 Nov
]


[27] <
http://www.videoray.com/Products/pric
ing.htm#replacementparts
> VideoRay


Product Line,
Various sections used [2003, 10 Nov
]



[28] <
http://www.connectworld.net/cgi
-
bin/iec/fullpic?apuvrVeM;CAB008;4
> IEC CAB00
8 24
Gage Wire [2003, 8 Nov]


[29] <
http://www.ocean.washington.edu/people/grads/scottv/exploraquarium/rov/parts.html
> UW
Exploraquarium, ROV Parts list [20
03, 10 Nov]


[30] <
http://www.iboatingsupplies.com/s/Marine_Sealants/Marine_Sealants_Item_S1.htm
> Marine
sealants, Various sections used [2003, 12 Nov
]