BUILD REPORT
To: Dr Hubbard
Date: Monday January 14th, 2008
Team 3 Members:
Rachel Byers ___________________________
Alex Crandall ___________________________
Valerie Kizell ___________________________
Kelly McGrail ___________________________
Connor O’Shea __________________________
Supervisor
Dr. Jimmy Chuang ______________________
i
CONTENTS
List of Tables ................................................................................................................................................. ii
Introduction .................................................................................................................................................. 1
Components .................................................................................................................................................. 2
Control System .......................................................................................................................................... 2
Thrusters ................................................................................................................................................... 3
Frame ........................................................................................................................................................ 4
Cameras and Light..................................................................................................................................... 5
Ballast ........................................................................................................................................................ 6
Power Supply and Tether .......................................................................................................................... 6
Budget ........................................................................................................................................................... 7
List of Items to be Determined ..................................................................................................................... 9
Control System .......................................................................................................................................... 9
Thrusters ................................................................................................................................................... 9
Ballast ........................................................................................................................................................ 9
Tether and Power Supply .......................................................................................................................... 9
Progress Summary / Schedule .................................................................................................................... 10
Appendix A – Gantt Chart ........................................................................................................................... 11
Appendix B – Technical Drawings ............................................................................................................... 12
ii
LIST OF TABLES
Table 1 - Parts List for Control System .......................................................................................................... 2
Table 2 - Labour Time for Control System .................................................................................................... 3
Table 3 – Parts List for Thrusters .................................................................................................................. 3
Table 4 – Labour Time for Thrusters ............................................................................................................. 4
Table 5 - Parts List for Frame ........................................................................................................................ 4
Table 6 - Labour Time for Frame ................................................................................................................... 5
Table 7 - Parts List for Cameras and Light..................................................................................................... 5
Table 8 - Labour time for Cameras and Light ................................................................................................ 5
Table 9 - Parts List for Ballast ........................................................................................................................ 6
Table 10 - Labour Time for Ballast ................................................................................................................ 6
Table 11 - Parts List for Power Supply .......................................................................................................... 6
Table 12 - Labour Time for Power Supply ..................................................................................................... 7
Table 13 - Budget .......................................................................................................................................... 7
1
INTRODUCTION
SWORDFISH (Submarine With Onboard Recording Device For Inspecting Ship Hulls) is a remotely
operated ROV that is being designed and built for the purpose of underwater ship inspection. It is
powered by four thrusters; two horizontal thrusters, one vertical thruster and one lateral thruster. The
ROV is operated and controlled by one person on the surface and has the ability to dive down to a depth
of 30ft. A tether is used to communicate with the ROV and provide feedback from two cameras (one
mounted facing forward and one mounted facing upward). The forward facing camera is used when
navigating the ROV and when inspecting the side of the ship hull. The second camera, facing upwards,
allows inspection of the bottom of the ship hull from below. The ROV is compact, lightweight and
relatively inexpensive, which makes it an ideal tool for underwater inspections.
This report summarizes the final design and outlines the work that needs to be done to assemble the
final product. Included are descriptions of the final design, technical drawings, a budget and a Gantt
chart for the winter term. The ROV was designed in the fall semester and a prototype will be built and
tested in winter 2008.
2
COMPONENTS
The ROV can be divided into 6 systems: control system; thrusters; frame; camera and lights; ballast; and
power supply and tether.
CONTROL SYSTEM
The control system includes a joystick for user input, a main control board with microcomputer, an LCD
screen and four motor control boards. The joystick consists of four potentiometers that measure x-axis,
y-axis and z-axis movement of the joystick and the position of a slider. These four voltage signals will be
converted by the control system into 12V DC current to be sent down the tether to the ROV to actuate
four thrusters. The control boards and joysticks will be mounted inside a plastic case that will be used
onshore as a controller unit.
The microcomputer can be programmed with a PC and a serial cable connection. The control system will
be entirely assembled and programmed by the team but occasional consultation with the technicians
may be required.
The use of a depth gage will allow for feedback control. The control system will be able to keep the ROV
at a set depth while the user is focused on piloting the ROV and inspecting the hull of a ship. The set
depth and actual depth will be reported to the operator on the LCD screen. A steady, controlled depth
will improve the video image quality. When the ROV is being tested for depth to satisfy the maximum
depth design requirement, the output from the depth gauge calculated for thirty feet can be verified.
This output can then be programmed into the microcomputer code as a lower limit to prevent the ROV
from operating at unsafe depths. Should the user find a point of interest on the hull of a ship, the depth
can be noted for future inspection or repair.
Table 1 - Parts List for Control System
Need
Main control chip
Main control board
Display
Motor control
Wires
Controller power supply
Joystick
Depth gage
Compass
Controller case
Item
Basic Stamp 2sx Module
Super carrier board
2x16 serial LCD screen
HB-25 Motor Controller Two Pack
Pluggable wires
9 V battery
3 axis + slider
TBD
Underwater compass
Plastic box
Quantity
1
1
1
2
3
2
1
1
1
1
3
Table 2 - Labour Time for Control System
Type
Assembly
Technical Consultation
Programming
Time
6h
4h
6h
Description
Connect all hardware
Consult with Greg Jollimore for programming or hardware
Write a PBASIC code to drive the controller board
THRUSTERS
The thrusters are made from bilge pump replacement motor
cartridges (figure on left) that are modified by the team. The
impeller will be removed and a collet shaft adapter will be used to
couple the motor shaft to a propeller. An analysis will be completed
after the thrusters are obtained to determine the optimal propeller
size and shape to maximize thrust. The motor lead wires will be
attached to the tether using waterproof connectors. The thrusters
require 3 Amps of 12 volt DC current and are capable of operating
at the maximum depth of the ROV (30ft). They are approximately 4
½ inches long and 2¼ inches in diameter.
The thrusters are mounted to the frame using a piece of PVC pipe
with the end cut to match the profile of the thruster. Adhesive and
plastic tie wraps secure the thruster in place. The mounting pipe is attached to a PVC T joint, bored out
to 57/64”, which can slide along the frame allowing the position of the thruster to be adjustable. The
thrusters are mounted so that they are inside the frame for protection and the propellers are not
blocked by any other components. The horizontal thrusters are mounted 1 5/8” above the keel to
prevent the ROV from pitching. The vertical and side thrusters are mounted on the same vertical pipe
and the position of this pipe, forward and back, will be determined experimentally. The vertical position
of the vertical thruster will not affect the attitude of the ROV when the thruster is engaged. The vertical
position of the lateral thruster will affect the roll of the ROV when it is engaged. The optimal vertical
position of this thruster as well as the lateral position of both thrusters will be determined
experimentally. The thrusters will be entirely assembled by the team but occasional consultation with
the technicians may be required.
Table 3 – Parts List for Thrusters
Need
Motor
Propeller
Shaft/coupler
Connectors
Thruster Mounts
Item
Johnson Mayfair 750 GPH bilge pump
40mm 3 blade prop (2pack)
Collet shaft adapters
Waterproof wire connectors
Built with frame
Quantity
4
2
4
8
4
4
Table 4 – Labour Time for Thrusters
Type
Construction
Assembly
Time
10 h
5h
Electrical
2h
Technician Consultation
1h
Description
Remove impeller, fix collet adapter, attach propeller
Fix thrusters to mounting device with tie-wraps, apply
adhesive
Connect motor lead wires to tether with waterproof
connectors
Possible issues include mounting and electrical hookup
FRAME
The frame (shown in figure on left) is used to protect
the internal components including thrusters, cameras,
lights, meters and gages; to provide structural support;
and provide mounting locations for these devices. PVC
pipes are connected together using “T” and 45° joints.
The PVC pipe is glued and fitted into the joints. PVC
pipe with diameter ¾” was chosen because it meets the
strength requirements as determined from a FEM
analysis yet it is small, inexpensive, and minimizes drag.
Detailed drawings of the frame can be found in
Appendix B. The frame will be entirely assembled by the
team but occasional consultation with the technicians
may be required.
Table 5 - Parts List for Frame
Need
PVC Pipe
Joints
Paint
Sealant/Glue
Item
¾”, length=13.5”
¾”, length=11.5”
¾”, length=16.5”
¾”, length=1.5”
¾”, length=1.25”
¾”, length=16.5”
¾”, length=11.5”
¾" T joint bored to 57/64”
¾" T joint
¾" female 45deg schedule 80
Waterproof red paint
PVC glue / cement
Quantity
3
2
4
12
7
2
2
17
4
16
1
1
5
Table 6 - Labour Time for Frame
Type
Construction
Construction
Assembly
Finishing
Time
5h
10 h
10 h
2h
Description
Cut PVC pipe lengths
Construct mounts
Assemble then glue pipe to joints
Paint frame
CAMERAS AND LIGHT
The waterproof cameras (shown in figure on left) and light have
been purchased from suppliers and are fixed to the ROV using the
same mounting scheme as the thrusters. They are located inside the
frame to protect them and nothing is mounted in front of them. The
cameras are equipped with LED lights; however, a more powerful
light is mounted above the forward facing camera to provide more
light for maneuvering and inspecting in the forward direction. The
cameras will be modified by the team. The factory installed weights
and back fin will be removed in order to mount the cameras to the
frame, reduce weight, and reduce drag. The cameras and lights will
be mounted by the team but occasional consultation with the technicians may be required.
Table 7 - Parts List for Cameras and Light
Need
Item
Quantity
Underwater flashlight
Underwater cameras
Diving flashlight
Neptune EZ 7" color w/ 30m cable and extra camera
1
1
Table 8 - Labour time for Cameras and Light
Type
Construction
Assembly
Electrical
Time
5h
3h
1h
Description
Modify cameras, remove factory ballast
Fix cameras and light to mounting device with tie-wraps,
apply adhesive
Connect cameras to onshore screens and power source
6
BALLAST
The ballast system will be comprised of buoyant materials at the top of the ROV and heavy materials at
the bottom of the ROV to provide stability in the roll and pitch directions. Light weight ballast will be
constructed from a large PVC pipe with two end caps attached and filled with air. The weights previously
removed from the cameras will be used for the heavy ballast. The mounting location and mounting
method are to be determined. The ballast will be designed and constructed by the team but occasional
consultation with the technicians may be required.
Table 9 - Parts List for Ballast
Need
Item
Quantity
Low density
PVC pipe
End caps
Extra steel weights from cameras
1
2
4
High density
Table 10 - Labour Time for Ballast
Type
Construction
Assembly
Time
1h
2h
Description
Cut PVC pipe to length and cement end caps to PVC pipe
Mount high density and low density fixed ballast to frame
POWER SUPPLY AND TETHER
The power supply is a 115Amp-h automotive battery located at the surface. The batter chosen is a deep
cycle 12V battery as it is able to be discharged and recharged numerous times. An automatic battery
charger was purchased to recharge the battery, allowing the ROV to complete multiple missions. The
power is provided to the ROV by means of a neutrally buoyant tether. This tether supplies power
(control) to the 4 thrusters, provides power to the cameras, returns the video feedback from the
cameras, and returns feedback from the depth gage. The tether will be assembled from multiple wires
held together and waterproofed with 3M shrink wrap. Light weight material will be added to the tether
to make it neutrally buoyant. The power supply and tether will be assembled by the team but occasional
consultation with the technicians may be required.
Table 11 - Parts List for Power Supply
Need
Item
Supplier
Quantity
Power source
Charger
Floaters
Power Cable - 4 Motors
Underwater Connectors
Deep Cycle 115 Amph 12V DC Battery
Automatic 12V DC Battery Charger
Foam
8 conductor neoprene insulated cable (50ft)
JWPF Series Waterproof Connectors
Canadian Tire
Canadian Tire
WalMart
McMaster Carr
Digi-Key
1
1
2
1
10
7
Table 12 - Labour Time for Power Supply
Type
Construction
Time
5h
Assembly
Technical Consultation
2h
2h
Description
Wrap all wires using waterproof shrink wrap, heat shrink
wrap
Connect tether to power supply and controllers
Possible issues include material selection and assembly
BUDGET
The budget below represents actual costs of items that have already been purchased. Approximately
75% of items listed in the budget have been purchased. The remaining items are shown with an
estimated cost that is based on prices sourced from suppliers. This budget is not finalized due to issues
such as unexpected duty charges and Canadian dollar value fluctuations. Additionally, in some cases the
costs of small items were estimated.
The Dalhousie Department of Mechanical Engineering has approved a $3,000 grant for the project
courtesy of Shell Canada. This grant is expected to cover all costs associated with the project. In the
event that the costs exceed $3000, the team will fund the remaining difference.
Table 13 - Budget
Need
Main control
chip
Main control
board
Display
Motor control
Wires
Controller
power supply
Item
Supplier
Control System
Quan.
Cost
Ship.
Total Cost
Basic Stamp 2 SX Module
Parallax.com
1
$59.00
$23.86
$82.86
Super carrier board
2x16 serial LCD screen
HB-25 Motor Controller
Two Pack
Pluggable wires
Parallax.com
Parallax.com
1
1
$20.00
$30.00
$$-
$20.00
$30.00
Parallax.com
Parallax.com
2
3
$79.95
$5.00
$$-
$159.90
$15.00
9 V battery
Cdn Tire
Crandall
Family
2
$5.00
$-
$10.00
1
Donated
$-
$-
Omega.com
Halifax Scuba
1
1
$665.00
$50.00
$30.00
$-
$695.00
$50.00
Wal-Mart
Thrusters
1
$50.00
$-
$50.00
IMP Group
4
$21.20
$10.95
$95.76
Joystick
3 Axis + Slider
Depth gage
Compass
Controller case
Omega PX439-015GI
Underwater compass
Plastic Box with Brackets
(approx 4" cube)
Motor
Johnson mayfair 750 GPH
bilge pump
8
Propellor
Shaft/coupler
PVC Pipe
Joints
Paint
Sealant/Glue
Underwater
cameras
Underwater
flashlight
Low density
High density
Power source
Charger
Power cable
for 4 motors
Cable
Waterproofing
Underwater
connectors
Tether
Buoyancy
40mm 3 blade prop
(2pack)
Tower
Hobbies
Tower
Collet shaft adapters
Hobbies
Frame
3/4" (10ft)
Cdn Tire
3/4" T joint
Cdn Tire
3/4" female 45deg
Cdn Tire
Waterproof red
Cdn Tire
PVC glue / cement
Cdn Tire
Cameras and Light
Neptune EZ 7" monitor, 2
Luluparts.co
cameras, and 30m of cable m
Diving flashlight
Nautilus
Ballast
PVC pipe
Cdn Tire
End caps
Cdn Tire
Luluparts.co
Camera weights
m
Power Supply
Deep Cycle 12V DC Battery Cdn Tire
12V DC Battery Charger
Cdn Tire
8 conductor neoprene
McMaster
insulated cable (53ft)
Carr
Heat Shrink Waterproof
Buyheatshrin
Tube
k.com
JWPF Series 2.0mm
Waterproof Connectors
Digikey USA
TBD
2
$16.99
$18.99
$52.97
4
$10.00
$-
$40.00
4
21
16
1
1
$6.98
$3.00
$3.00
$10.00
$7.00
$$$$$-
$27.92
$63.00
$48.00
$10.00
$7.00
1
$299.90
$149
$448.90
1
$60.00
$-
$60.00
1
2
$20.00
$5.00
$$-
$20.00
$10.00
4
NA
$-
$-
1
1
$109.99
$59.99
$$-
$109.99
$59.99
1
$110.24
$40.00
$150.24
25
$3.25
$35.00
$116.25
10
$8.73
$20.00
$107.30
1
$20.00
$-
$20.00
1
1
1
$8.00
$10.00
$10.00
$$$-
$8.00
$10.00
$10.00
1
$15.00
$-
$15.00
Caulking
Sand paper
Tie wraps
Caulking
Sand paper
Tie wraps
Box
Building
supplies
Long
distance/faxes
Rubbermaid
Wal-Mart
Mounting
Cdn Tire
Cdn Tire
Cdn Tire
Misc
Wal-Mart
Misc
Misc
1
$50.00
$-
$50.00
Misc
Misc
1
$50.00
$Subtotal
Tax
Total
$50.00
$2,703.08
$387.43
$3081.51
9
LIST OF ITEMS TO BE DETERMINED
CONTROL SYSTEM


A method of exciting the depth gauge at proper voltage must be determined.
The power must be regulated from the main battery to the motor controllers.
THRUSTERS


A generic propeller was chosen for this build report; however, an analysis will be performed to
determine the optimal size and shape of the propeller and attempts will be made to source the
best possible propeller.
The issue of coupling the motor and the propeller will be addressed after the selected motor
and propeller are confirmed.
BALLAST

An analysis will be performed to determine the amount of fixed ballast required to maintain
ROV stability in the conditions that might be encountered in the harbour.
TETHER AND POWER SUPPLY

A method of making the tether neutrally buoyant must be determined. The tether will be
neutrally buoyant in salt water; therefore, it will sink when the ROV is tested in a fresh water
pool.
10
PROGRESS SUMMARY / SCHEDULE
The team has recently completed the design stage. A design has been selected and all of the
components to be used in the ROV have been chosen and sourced. Approximately 75% of these
components have been purchased including all items which might have a significant lead time
associated with them.
All team members have been trained to use the machine shop and construction of the ROV frame is
currently taking place in the machine shop. The project schedule that was developed in the fall term is
being adhered to and the build stage of the project is expected to be complete in early March. This will
allow sufficient time for testing. The team will continue to make an effort to adhere to the schedule, and
update it as necessary.
Individual components will be tested to determine their capabilities as they arrive. Upon verifying the
adequacy of the components, the assembly stage will commence. Beginning in March, the ROV will be
tested in its assembled form. Time is allotted in mid March to perform repair and modification work
that arises from testing.
Finally, the device will be inspected and the final report and presentation will be prepared in time for
their respective submission dates.
A Gantt chart summarizing this schedule is attached in Appendix A.
11
APPENDIX A – GANTT CHART
12
APPENDIX B – TECHNICAL DRAWINGS