Senior Design I
MECT 4275
Fall, 2013
SECTION TUESDAY/THURSDAY 4:00PM – 6:00 PM
Team AquaForce
Houston, TX
MATE 2014
TEAM MEMBERS:
Santos Ortiz
Christopher Munoz
Vicente Mora
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TABLE OF CONTENTS
ABSTRACT ................................................................................................................................... 2
BACKGROUND: .......................................................................................................................... 3
History of the ROV ............................................................................................................. 3
Milestones ........................................................................................................................... 4
OBJECTIVES ............................................................................................................................... 4
MATE ROV COMPETITION .................................................................................................... 5
GOALS......................................................................................................................................... 11
MARKET RESEARCH ............................................................................................................. 11
Thrusters ........................................................................................................................... 12
Bouyancy Control ............................................................................................................. 13
Control System.................................................................................................................. 13
COST ANALYSIS ...................................................................................................................... 13
DESIGN FOUNDATION: ......................................................................................................... 15
Focus ................................................................................................................................. 15
Mechanical Design Process .............................................................................................. 15
Frame ................................................................................................................................ 16
Thrusters ........................................................................................................................... 16
Connectors ........................................................................................................................ 17
Combining Concept and Design ....................................................................................... 17
Electrical Design Process .................................................................................................. 21
REFERENCES ............................................................................................................................ 22
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ABSTRACT
Throughout the evolution of technology, humans have been capable of doing some of the
unthinkable, from building airplanes to high power vehicles. The world of today has been
ultimately explored through curiosity and through those who have contributed by innovation of
systems that aid in further exploration. Humans have been capable of discovering beneath the
earth, land, solar system, and the underwater world. The ability to explore under water is of high
importance because the earth is made of about 70% water. There’s so much more to discover and
improve. These qualities enable our team to tackle the challenge of further exploration through
the use of technology.
Team Aquaforce will innovate and produce an ROV with the capabilities that enable the
industry to benefit from. A three person team that has the ability to deliver quality and a cost
efficient design intended to compete in the mission. Our ROV, Juggernaut, will introduce some
neat capabilities acquired through engineering design and innovation. Aquaforce utilizes
methods of SolidWorks and Pro-Engineer to produce part models, assembly models, and
drawings. With these tools Aquaforce is capable of manufacturing any of the needed components
excluding purchased components.
Aquaforce introduces their innovative designed ROV, Juggernaut. Juggernaut is designed
with easy disassembly and mission intent. Its aluminum side plates and ballast buoyancy control
features allow for a lightweight submersible design. Precision controls are delivered instinctively
by our customized control panel located in the front of the ROV.
This report will showcase the many details that go into the making of Juggernaut. The
details range from design intent, precise calculations, and establishing the major to minor
characteristics incorporated into developing the ROV. Our design intent is our focus and we
want to demonstrate that juggernaut has the best qualities for the ROV mate competition.
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BACKGROUND:
HISTORY OF THE ROV
Throughout the history of ROV’s there have been major contributions by many creative
and innovative individuals across the world. The meaning of exploration has been taken to a new
horizon from many different classifications. Individuals in our past have managed to create some
of the most land marking devices that we have utilized as foundations to what we have improved
in the new ages. Before we discuss some of the contributors it is important to understand the
concept of design that is considered when thinking of such an innovation.
The principle of design applies into basically any invention in our world. With ROV’s the
design aspect revolves around the environment and the job it will be tasked out to accomplish.
For example, there are three different classifications of ROV’s: Working class, Observation
class, and Special class. The working class ROV does tend to have large body styles and
typically handle all heavy tooling operations. Furthermore, they have multi-function
manipulators allowing them to perform construction projects beneath the sea. The observation
class ROV’s are normally a visual eye for the explorer. Observation ROV’s are designed around
gathering data and are typically utilized in small jobs. However, these ROV’s are not only
limited to seeing. They tend to come prepared with tooling packages that allows them to perform
the full functions of an underwater vehicle. Lastly, the special use class ROV’s are geared
towards specific jobs. Special use ROV’s are designed around the specific task they will be
performing; for example, their contributions to the excavation of frayed cables. Our project will
focus on the observatory class ROV’s.
Now that we have briefly introduced the different types of ROV’s, let’s discuss how
these classifications came about. As with any discovery, once an invention has been created or
an exploration has been made, the question following is usually, “Well, how do we improve it?”
The exploration of oil allowed the oil industry to take that question and run with it so to speak.
With the discovery of oil, an abundance of industries were able to thrive in order to contribute
and improve the process. However, our focus is within the ROV realm. The individual who gets
the credit for the first built ROV is, Dimitri Rebikoff. The ROV created by Rebikoff was named
the “POODLE” and it contributed a field of development for innovators because of the flaws it
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had. These developments flawed in that they were noisy, hydraulics failed, and the bottles
leaked. As time went by there were numerous of improvements contributed to the ROV idea. For
example, in 1961 the U.S Navy managed to develop the “CURV.” The CURV, meaning, CableControlled Underwater Research Vehicle managed to benefit the Navy by retrieving objects
under water. In fact, the CURV managed to retrieve a lost atomic bomb off the coast of
Palomares, Spain in 1966. As time went by, ROV’s continued to improve and along came the
Japanese with, “KAIKO,” a revolutionizing ROV created in 1993 that had the worlds’ deepest
diving depth capability at 35, 791 feet. Throughout the history of ROV’s there have been an
immense number of successes. More and more underwater discoveries have been made thanks to
the continuous improvements and the future of these vehicles looks promising.
MILESTONES
In order to obtain a successful design, Aquaforce needs to implement every aspect of the
planning process. From utilizing production applications such as Gantt charts and WBS
structures to design a work flow, Aquaforce was capable of staying on track demonstrates a brief
presentation of some of the progress we have completed and how we reached those target goals.
Furthermore, it was important for us to reach the milestones that we placed on important work
zones. For example, our first milestone consists of producing an efficient design. Our
accomplishments were dependant on meeting those illustrated milestones and the addition of the
tools needed to control them were crucial.
OBJECTIVES
Senior Design team AquaForce from the University of Houston Northwest Campus will
design and build a Remotely Operated Vehicle (ROV). The team (Santos Ortiz, Christopher
Munoz and Vicente Mora) will enter the ROV in the Regional Marine Advanced Technology
Education (MATE) ROV Competition hosted in Houston, Texas at the NASA Sonny Carter
Training Facility. The competition is structured on a point system that includes: a mission,
technical report, engineering presentation, poster display, and safety inspection. In conjunction
with the competition, AquaForce will incorporate the LabView software to control the ROV and
the various components needed to complete the mission.
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MATE ROV COMPETITION
The MATE competition consist of three classes – EXPLORER, RANGER, and SCOUT.
Depending on the class the the competition will require specific guidelines in order to compete in
the competition. AquaForce will be entering into the EXPLORER class which consist of high
schools, community colleges and universities. The guidelines are based from the International
competition that will be held in Alpina, Michigan. The regional competition can but is not
required to incorporate the same tasks as the International competition. The scoring is totaled
from the Mission, Technical Reports, Engineering Presentation, Poster Display and Safety
Inspection. The scoring is divided as follows for a max of 580 points:
Mission = 300 +10 for safety +10 for organizational effectiveness = 320
Technical Report = 90
Engineering Presentation = 90
Poster Display = 50
Safety Inspection = 30
In order to participate in the Mission section of the competition the ROV must first pass the
Safety Inspection. The team will be allowed two attempts to pass the saftey inspection. The
mission will consist of four tasks that the team will need complete. The teams will have two
attempts to complete the mission of which the highest will be taken. Each team will be allowed a
five minute setup period, fifteen minutes to perform the mission and five minutes to clear the
mission area. Three design parameters that must be taken into consideration for safety are the
power requirements. Each team will be given a 48 Volt power supply that will run a max a 40
amps. If less voltage is required in the system the voltage reduction must be made inside the
ROV and not from pool side. If fluid power is required a max of 150 psi must be use and a max
of 10 psi pneumatic pressure.
Mission overview in the categorie we are; EXPLORER class will compete in ONE mission that
consists of the following three tasks:
Task #1: SHIPWRECKS
Explore, document, and identify an unknown shipwreck recently discovered in sanctuary waters.
Task #2: SCIENCE
Collect microbial samples, measure the conductivity of the groundwater emerging from a
sinkhole,
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deploy a sensor, and estimate the number of zebra mussels found on the wreck.
Task #3: CONSERVATION
Remove trash and debris from the shipwreck and surrounding area.
We have a total 20 minutes to do our task; first five minutes to set up the mission task, fifteen
minutes to do the mission and other five minutes to break down and exit the mission; if we finish
before this time we will recive extra points. If in the fifteen minutes of doing the task we have
not finish the props will be retired and lose all the poitns.
Mission scenario
We are exploring a ship wreck in a body of water
Mission task
The task can be done at any other we find sutible
Task 1: Shipwreck
We have to measure the length, width, and higth of the boat. Its up to us on how are we going to
measure but it has to match the number with the judges with a margin of error of +/- 5 cm.
We have to simulate a sonar scan; on the proops there is going to be targets; ROv has to stay still
for five second and take three different pictures of the target as shown bellow. The judges have
to be able to see the ring in order to recived full points.
We recive five points for each successful scan.
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We need to create a photomosaic, we will need to take five pictures of the shipwreck and then
stitched together in place
A photomosaic example of the MATE Center shipwreck. Note that the fourth
photo from the left is incorrectly “stitched” in place.
We need to find what type of ship is ; there are three types: wooden sailing schooner, a steam
driven paddlewheel ship, and a propeller driven bulk freighter. There will be clues on the
wreckage.
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Find the cargo of the ship, the cargo will be a milk crate we must unlock the hatch on one side of
the container then open the cargo container. The amount of force should take to open is about
five Newtons
We need to find the date stamp of the ship; its has to be written on a 5 cm x 15 cm rectangle
plastic made of PVC; we will recive 5 points for diplaying the date
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Last one we going to use is the ceramic dinner plate from the wreckage; its going to be simulated
by a plastic plate. We will recice point by controling this plate when we get the plate from the
ROV.
Task 2: Science
We have to measure conductivity; we have to build a conductivity sensor; this will be simulated
thought a 2 gallon bucket with a 1 ½ inch hole on the top with salt water mixed. To ensure we
are reading it right we have to introduce the sensor 7.5 cm inside the bucket; the units have to be
in mile Siemems (mS).
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We have to take microbaits mats sample that will be simulated of a plastic cup fill with
agar(japanese jellow). To recived full point we will have to remove 150 ml of agar from the
plastic cup; if we return with the entire cup we will recive 0 points.
With the legth measurement we should be able to measure the numer of zebra mussels in the 50
x 50 quadrat.
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Task 3: Conservation
The ROV has to pass thought a 75 cm x 75 cm hole and inside there retrieve a plastic bottle
without cap, and a simulates glass bottle made of PVC. The final piece of debris is an 8-lb
Danforth anchor with a length of chain attached. This anchor and chain will NOT be attached to
the anchor line rope, but will be a separate item.. Tha plastic botle could be from 500 ml to 1 L
bottle , this bottle will not have a cap. The simulated glass bottle is going to fill too. The anchor
line rope debris will not weight more than 10 Newtons in water. The danforth anchor itselve will
weight less than 100 Newtons in water.
GOALS
The goal for this project is to win the Regional MATE ROV Competition hosted in
Houston Texas on April 26, 2014. In order to accomplish this goal the ROV will need to have the
highest total score at the competition. AquaForce will incorporate the appropriate equipment and
design to effectively carryout the tasks specified by the mission.
MARKET RESEARCH
The three areas a ROV must incapsulate our manuerverability, bouyancy control, and
processing control. The manuverability of the ROV will be controlled using thrusters. Thrusters
are predominantly hydraulicly or electrically controlled. The hydraulic or electric control
translate rotary force via a turbine into lateral force called thrust that can be measured in pounds.
With the proper placement of the thrusters the ROV can be maneuvered in any direction. The
total bouyancy of the ROV will determine whether or not the system will sink or float. Both
conditions are equally important because you must be able submerge to depth but also return to
surface. Most ROV’s control bouyance by means of pressure tanks. The pressure tanks change
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the amount of air volume in the ROV. Pressure tanks can incorporate a piston or inner tube to be
able to control the air volume. Finally, the ROV must have a control system to be able to
remotely control the vehicle and the various components. ROV’s can incroporate an array of
tools from cameras, arms and lights to specific tools than can be used for repairs to underwater
pipelines.
THRUSTERS
Three thruster manufacturers taken into consideration are SeaBotix, Seamor and Crust
Crawlers. All three thrusters are powered by DC motors and the determining factor for the use
will be based from the parameters listed below.
THRUSTER PERFORMANCE/COST
Thruster
Electrical Requirements
Performance
Depth
Cost
Seamor
24VDC or 48VDC
10 lbs
1000 ft
SeaBotix
19.1 VDC
6 lbs
500 ft
$700
Crust Crawler
12 VDC to 50VDC
15 lbs
300 ft
$600
One determining factor in choosing a thruster is the power requirement. The competition will
supply 48 Volts DC and if the thruster can be run directly, less modules and programming could
be used to run the thruster rather than stepping down the voltage. Thrust capacity can also be
considered but most of the operations undertaken during the competition mission will not require
that that the ROV have a high velocity. Depth in this situation will only be the depth of the pool
which will be 10 meters or approximately 33 feet.
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BOUYANCY CONTROL
The buoyancy of the system will be controlled by pressure tanks. The tanks will be made
out of PVC tubing and caps. The option of how to change to air volume can either be by
displacing a piston or inflating a tube inside the pressure tank. The system will need to be
pneumatically powered and metered in order to vary the buoyancy.
CONTROL SYSTEM
The ROV will need a system that can simultaneously operate the thrusters, camera and
other components included in the system. The “brains” of the ROV will be a micro-controller.
This controller will be able to modulate the thruster and supply the correct amount of power to
each of the components. The controller will be controlled and programmed using the LabView
software. Three controllers considered are the Seamate sold by the MATE competition website,
Arduino and LabView. The Seamate is an Arduino based platform that is set up to run four
thruster and supply voltage to two other components. Because the ROV will need compatibility
for more than two other components more than one controller will be need to control the ROV.
COST ANALYSIS
We were looking for prices of the most important parts for the ROV like thrusters, arm,
camera, control and others. We are planning to build and design the frame of the ROV thud
focusing on material of the frame and not the frame its self The first thing was search for the
ROV was the thruster we find many varieties with deferent types of depth, thrust performance
and electrical requirement; we found one from SeaBotix, Crust Crawker and Seamor each one
being from different vender and with different performance we have chosen the Seamor due to
its ratability to work under thousand feet underwater.
The theater were all other cables pass through we found that for every hundred feet it’s
going to be hundred dollars; it’s kind of a standard price. The pressure housing for the electrical
components goes for hundred based on the size of the electrical components required on the
previous year competition. We need a software to program the communication between the user
and ROV after research LabView gives the liberty that the control requires.
Control board is where everything is connected the control, cables, and all other electrical
components; we found one that was good enough for the ROV we are going to build.
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Underwater cameras so we know where the ROV is located and help us see the task we are going
to do; the ROV arm depends of what the competition is going to required; based on the previous
year competition the arm that did their task best was around two hundred dollar.
For the completion we are required to build our own obstacles; MATE will release the material
and the instruction on how are we going to put it together that have its own separated price as its
own. On the frame material we are looking to made out of aluminum because the toughness,
weight and cost.
Cost Analysis
Item
Cost USD
Thruster
$2800
Tether
$100
Pressure Housing
$100
LabView
$700
Control Board
$700
Camera
$600
Arm
$200
Frame Material
$500
Competition Materials
$200
Total:
$5900
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DESIGN FOUNDATION:
FOCUS
Throughout this senior design project our mission is to maintain focus. We feel that if we
focus on the right components to complete the ROV Mate competition, we will be in comfortable
standing with our design. We want to begin our focus by studying some of the accomplishments
and benefits that championship teams before us mastered. By doing this, we have an edge on the
competition in that we may adopt and improve previous ideas without reinventing the wheel, so
to speak. Furthermore, we shall focus on the competition as a whole. We will develop an ROV
suitable for the competition that is up to par with the safety standards, possesses competitive
maneuverability and has a relative fair cost.
MECHANICAL DESIGN PROCESS
The design process we wanted to approach our ROV with was one with an open minded
intended design revolved around the competition. Aquaforce will utilize a crawl, walk, and run
phase mentality in order to mitigate probable mistakes. Throughout the crawl phase of our design
process we wanted to focus on the basics. Aquaforce laid the foundation of an ROV by doing
extensive research on the components and the mathematics that go behind it. Once we obtained
the knowledge and concepts, we put our ideas on the drawing board. We focused on sketching
multiple frame concepts until we were completely satisfied with a final base model. The
sketching phase consisted of multiple ideas being thrown back and forth until we were satisfied
with an idea that would provide us with less re-work because, let’s face it, the re-works are
coming.
Ok. The preliminary sketching is complete. Now what? Well, this is where the “fun”
begins. Our next focus was to take our crawling and make it to the walking phase of our design
process. Our team worked rigorous hours to produce a model in a 3D and 2D program by
utilizing Solidworks modeling software. The use of Solidworks not only facilitated our
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illustrations but also allows us to easily transfer our data to CNC mills and lathes for
corresponding parts. In addition, if there are/were any suggestions that benefit us, we can easily
make corrections and fix nonconformities by editing the part model in Solidworks. In addition,
Solidworks synchronizes all of its ‘add-ins’ making it easy to cross edit from part model to
drawing.
FRAME
When plotting our ideas for the frame, Aquaforce wanted to maintain a frame design that
was simple. We focused on trying to keep it as simple as possible while also keeping some of the
previous champions’ ideas in mind. We understand that the maneuverability of the ROV is
dictated by the drag forces of the frame structure under water. Therefore, we wanted to design a
frame that would give us the weight needed to submerge it while having little surface area
opposing the motion of the ROV under water. We also want to keep the frame at equilibrium
underwater as stated by “Archimides Principle” the buoyancy formula and the machnability of
the material we will be working with. At the same time we wanted to provide an efficient
platform for mounting the electrical housing and cross elements. The side plates provide
Juggernaut with an adequate amount of space of mounting for add-ons. The simple idea here was
to keep the design intent in mind. We focused on producing a frame that delivers the capability
of adjustments as easy as 1,2,3. The surface area of the aluminum side plates provides us with
the need to remove material by machining it off if needed per weight standards. Aquaforce also
equips Juggernaut with side slots that allow for the cross elements to be easily adjusted vertically
for weight distribution purposes and appearance.
THRUSTERS
When evaluating our options with thrusters, we compared and contrasted between the three
choices illustrated below.Our team wanted to focus on a low price thruster that would deliver a
sufficient amount of force to control the ROV under water. Our design allows for us to place
multiple thrusters to aid in buoyancy control and thrust force. However, we chose to equip our
ROV with only two thrusters because it is cost efficient and it enables us to control up and down
movements in other forms that we will later discuss. Seabotix seemed to be our best option when
it came down to thrusters. After comparing and contrasting our options, Seabotix was the one
that delivered a reasonable cost and the power requirements we needed.
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CONNECTORS
While focusing on design, Aquaforce also had to pay close attention to the movement controls of
juggernaut. Sure enough the controls are key components once calculations and designs are
complete but in order to control the Juggernaut, Aquaforce had to contemplate between various
options. We wanted to begin our connector concepts by paying close attention to the important
elements that would allow them to function. First, we focused on making them waterproof. Then
we focused on the ease of installation and cost.
Our primary concept to uniting a connection to the Juggernaut utilizes a simple cone
design to allow a tight fit onto the electrical housing. These air compressor brass hose nipples
facilitate the connection to the tether while being leak proof, secure, and cost efficient. We will
run any important wires through the inner diameter of the nipples.
COMBINING CONCEPT AND DESIGN
In order for the ROV to operate properly the concept of neutral buoyancy must be balanced in
the mechanical design. The approach taken was to first design a ROV and later compensate for
neutral buoyancy utilizing a variable ballast. In the first design of the Juggernaut, Aquaforce
wanted to control the upward and downward movement of the vehicle by constantly changing
the volume of air in the variable ballast. By adding air volume to the ballast, the vehicle will
reach a point of positive buoyancy at which point it would begin to rise or surface. In order to
stop the ROV in a certain position the air volume would be bled off immediately to achieve
equilibrium and neutral buoyancy. Likewise, to sink the ROV, air volume would be reduced
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below its neutral buoyancy to negative. In the same fashion the vehicle would sink and to control
its depth, the overall buoyancy would have to return to neutral to maintain its depth.
After realizing the design concept slightly more complicated than necessary Aquaforce
decided to incorporate two more thrusters. The thruster would now be placed at the rear of the
vehicle in a fashion that will not only control forward and backward movement but also move
the vehicle upward and downward. The thrusters are strategically placed at an angle thirty
degrees from the central axis in the y-axis and z-axis, for reference the center axis passing
directly through the center from front to back is the x-axis (illustrated below).
Utilizing the mounting angle, the thrusters can be operated in a fashion to give the vehicle
control in every direction. The concept here is cancelling out component forces to arrive at a
resultant force in one direction. In order to drive the ROV forward or backward all four thrusters
will be driven in the same direction. As shown below from a side and top view forces in the Y
and Z direction will cancel resulting in the forward or backward movement of the vehicle.
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The concept of this thruster setup becomes slightly more involved once the vehicle must be
rotated or moved up and down. In order to achieve this movement, the thrusters must be operated
in opposite directions. As illustrated below to achieve upward and downward movement the two
upper thrusters must differentiate in thrust direction as compared to the two lower thrusters.
Driving the two upper thrusters in the forward direction would cause backward and downward
component forces. While driving the two lower thrusters in the reverse direction would cause
forward and downward component forces. In this case since the component forces of the upper
and lower thrusters are not coincident, opposing forces will instead create a torque near the
central axis. The two downward forces will sum and in this way the torque will cause the nose of
the vehicle to be lower in relation to the central axis. The same concept is utilized in the
downward movement of the vehicle, only now the upper thrusters are driven in reverse and the
lower in forward. In order to rotate the ROV the thrusters are also driven in the opposing
direction but this time in the top plane. To rotate the vehicle front in a counter-clockwise
direction looking down from the top, the two left thrusters must be driven in reverse and the two
right thrusters must be driven with forward thrust. The same action will occur the two opposing
component forces will create a torque but this time aiding in rotation and the sum of the two
remaining forces will drive the back end of the ROV to complete the rotation.
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Now that the concept of the ROV movement control has been determined we may now
discuss the design of the variable ballast. In order to determine the amount of air volume needed
to suspend the ROV in neutral buoyancy we must determine the weight of the ROV in water.
Using Archimedes principle you may conclude that the weight of an object in water can be
determined by the volume of the object and the density of water. By determining the volume of
the object you know that it will also displace the same amount of volume in water. By using the
displaced volume and the density of water (.036 lbs/cu.in.) you may determine the weight of the
displaced water. This principle is what drives buoyancy; essentially the buoyant force is the
weight of the displaced water. The weight of the water would have a negative value and the
weight of the object would have a positive value as shown in the formula below.
𝐹𝐵=𝜌𝑉𝑜𝑏𝑗𝑒𝑐𝑡 −𝜌𝑉𝑑𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑑 𝑤𝑎𝑡𝑒𝑟
Utilizing the side plate to do an example calculation you can achieve to total ROV weight in
water. Aluminum has a density of .098 lbs./cu.in. and displaces 86.86 cu.in. making it weigh
8.47 lbs. in air. Using this same volume for the displaced volume in water you can determine that
the weight of water will be 3.13 lbs. Subtracting the weight of water from the initial weight you
reach that the side plate will weigh 5.34 lbs. in water. You can then use this same process to
determine the weight of the remaining components except for the pressure tank and ballast. The
process for determining the weight of the pressure tanks is the same, only now you must take
into account the most of your displace volume is air. For this calculation you must still determine
the weight of the object in air only now you must calculate the volume of air in the tank. The
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density of air is .00004 lbs./cu.in. and for this application the amount of air as compared to the
other object is negligible. For the pressure tank the weight of the object is 8.53 lbs. and just for
reference the air inside the tank weighs .01 lbs. and is negligible. The difference here is that you
are now displacing the entire volume of the cylinder. The after calculating the displaced volume
the displaced water weight is 17.30 lbs. If you refer back to the formula, this will leave you with
a -8.77 lbs. This is where the concept of a positive buoyant force comes into play. This negative
weight can now be referred to as a buoyant force and will be the same concept use to control the
variable ballast. After calculating all the weights of the components and buoyant forces, the
ROV’s weight in water is 10.42 lbs. This number is important because the variable ballast will
need to create a buoyant force equal to this weight in order to achieve neutral buoyancy. Since
we are utilizing a variable ballast, the tank should be able to go above and below the weight of
the ROV in water. Aquaforce determined an ideal ballast size would be 8 inch in diameter with a
total length of 9.5. This calculation is slightly different because you must be careful as to the
amount of water you will be displacing and the amount of air in the tank. The total length for the
volume displaced must include the top plate to the bottom of the dynamic piston. For this
application the variable ballast the Juggernaut will be using will create 15.75 lb. buoyant force.
Subtracting the weight of the ROV from you can determine that at full bottom the variable
ballast will create a 5.33 lb. positive buoyant force. In order to reach neutral buoyancy the air
volume inside the ballast will be reduced to equal the weight of the ROV. The ballast can also be
taken below the weight which will cause the ROV to sink.
ELECTRICAL DESIGN PROCESS
We are Mechanical engineers technology so our electrical background is not our strongest
subject in the matter; to design an electrical program we need an input (switches, PC,
microphone, etc.); then a black box where the processor, resistor are; and is where all the magic
is happen; and final the result.
For the input we want the ROV to be controlled by a PlayStation3™ controller (DualShock 3™);
because it has built in pressure sensor inside the controlled and we can programed that way that
we would be able to control the speed of the thrusters; and control how fast the piston of the
ballast goes down. When we press the button that makes the ROV go down and up with no much
force the ROV will go slow or fast; this way we will have a greater control of the ROV. The
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application that is controlling the ROV will be running in a laptop and that will be our widow to
see what the camera is looking.
The black box where the magic happen; there is not an actual black box here it’s just where all
the electrical information occur; for that we need a processor; we choose it’s the IMX 233
Olimex™ processor that have analog and digital output, that’s the reason we choose it, the
communication is through a RJ45 Ethernet cable; a contraire to a USB cable that can be only few
feet long; this one can be around 100 meters long (328 feet); after that distance the resistance
increase too much and the information does not get transmitted good. The processor is in charge
of sending current to the motors or air processor; we need to program so that we need to see how
much current it goes to the part; we are controlling the current by actuators on all the parts that
require movement. on the side of the motors it has to be bridge that does not let the energy
created by the motors to come back to the processor; if that energy goes back it will burn the
processor.
The result its simple; the motor moves, the piston goes up or down and the arm open or close.
The way we planned to program is though Labview™.
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"CrustCrawler Robotics." - The Worlds Leader in Providing Cutting Edge Robotics Kits,
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