Underwater Technologies
P08454 – Thruster for a Remotely Operated Vehicle
Anthony Squaire – Industrial and Systems Engineer – Team Lead
Alan Mattice – Mechanical Engineer – Lead Engineer
Brian Bullen – Mechanical Engineer
Charles Trumble – Mechanical Engineer
Cody Ture – Mechanical Engineer
Aron Khan – Electrical Engineer
Jeff Cowan – Electrical Engineer
Andre McRucker – Computer Engineer
Multidisciplinary
Engineering Design
Program
Project Scope
P06606 – An Underwater ROV
Derived from one of the most successful projects in RIT’s history
Mission:
To create a thruster for an underwater remotely operated vehicle (ROV) that is
integrated with an ROV light design. This design shall be accessible to any person or
persons who wish to use and/or modify it in the future.
Customers:
Dresser-Rand has graciously donated the majority of the funds for this project.
Hydroacoustics Inc. has supplied many resources to the project. Dr. Hensel and the
Mechanical Engineering Department have supplied leadership and guidance through
the design process.
Current Designs
Tecnadyne Model 260:
$4,000.00
High Power Consumption (80W)
Seabotix Model 150:
Very in-efficient in reverse
$1,000.00
•Only 1/3 of forward thrust
Inefficient Thrust
No possible design variances
Competitor company for Hydroacoustics Inc.
Top Right: Seabotix Model 150
Left: Tecnadyne Model 260
Customer Requirements
•Need more efficient thrust, ie. better thrust with lower power
consumption
•Must be easily mountable to the Hydroacoustics Inc. ROV
•Needs to be operational up to 400ft (121.92m) of water, roughly
173psi (1192.8kPa) of pressure
•Needs to work in a large range of temperatures
•Modular, open source design so that any person or persons can
use and/or modify the design
•Needs to comply with all federal, state, and local laws, including
the policies and procedures of RIT
Design Process
Decisions, Decisions, Decisions:
Shaft Seal – Decide between magnetic coupling or dynamic seal
Answer: The magnetic coupling was chosen because allows for a
much simpler seal, gives protection to the motor and
impeller, and is frictionless
Motor – Brushed or Brushless?
Answer: Brushless was chosen because of there being reduced losses
and the use of Hall Sensors for feedback
Impeller – Design or use pre-existent designs?
Answer: Decision was to use pre-existent impeller designs.
Computer muffin fans have perfect sized impellers for the
projects application.
Design Process
Nozzle – Rice or Kort Nozzle?
Answer: The Rice nozzle was chosen based on it’s reduced drag
through the fluid and a better geometry to promote
increased thrust
Communication – Use single microcontroller for all thrusters or single for
each?
Answer: Decision was to use a single microcontroller in each
separate thruster or light. Allows the ROV to “limp” on
Nozzle Comparison
Kort Nozzle
Rice Nozzle
Relatively Simple Geometry
Lower Drag Coefficient
High Circulation off Leading
Edge
Improved Flow Geometry
System Architecture
Water
Nozzle
Entrance
Water
Legend
Impeller
Water
Impeller
Shaft
: Water
: Forward Communication
: Feedback
User
Motor
Microcontroller
Motor Driver
Topside
Control (GUI)
Power
Board
Battery
Packs
Hall
Sensors
Nozzle Exit
Water
Final Design
Special Mechanical Features:
•Magnetic Coupling – No dynamic Seals
•Aluminum Housing – Lightweight and strong
•Rice Nozzle – Low drag and increased thrust
•Polymer Membrane – High strength PEEK (Polyetheretherkeytone) material
•Modular Housing – Used for both thruster and light
Final Design
Special Electrical/ Software Features:
•Feedback via Hall Sensors – Monitors position, speed and direction of the
rotor, allows for synchronous control and fine tuning
•Motor driver – 5.6A peak with over-current protection, enable,
forward/reverse, variable speed using pulse width modulation
•ATmega168 Microcontroller – Efficiently uses power, and has numerous
PWM channels
•Topside GUI – Made using GTK to control thrusters and lights
Board Layouts
Left: Microcontroller
Right: Motor Driver
ST Microelectronics Driver
ATmega168 Microcontroller
Engineering Specifications
•Must have a continual forward thrust of at least 4.8 lbf (2.18kg)
•Must have a reverse thrust at least ¾ the value of the forward thrust
•Power consumption must be limited to under 80W
•Impeller shaft must be balanced to within 0.001in (0.0254mm)
•Must withstand pressures up to 173psi (1192.8kPa)
•Should be of comparable weight and volume to both the Tecnadyne Model 260
and the Seabotix Model 150
•Needs to operate at ambient temperatures ranging from 38 to 75oF (3.3 to
23.9oC)
•Should be able to run for 168 hours without failures
Design Verification
Specification
Number
Design Specification
3
4
5
Physical Requirements
Continual Thrust
Motor Power Draw
Mountable to the prototype ROV originally designed in SD team
project P06606
Uses standard (off the shelf) fittings / connections
Seals must withstand at least 173 psi
6
Available Reverse Thrust
1
2
7
8
9
10
11
12
Output shaft must be balanced
Depth (Pressure)
Weight (in the air)
Weight (in the water)
Size Comparable to Market Competition
Operate at Varied Temperatures
14
Production and Document Constraints
Open Architecture Design
Open Source Documents and Drawings so that future SD teams
can utilize this design in future projects
15
Quality Control
Robust Design
16
Compatibility
Modular so that the housing design integrates with the SD team
project P08456
13
Unit of Measure
Marginal
Value
Ideal Value
Pass/Fail
lbf
Watts
4.8
80
12
50.4
Fail
Pass
Yes/No
Yes
Yes
Pass
Yes/No
Yes/No
Ratio Reverse
to Forward
Amplitude of
Vibration
(Inches)
Feet (psi)
Ounces (oz)
Ounces (oz)
Volume (in^3)
Fahrenheit
Yes
Yes
Yes
Yes
Pass
Pass
1/2
3/4
0.001
0.0001
400 (173)
40
28
18.8851
38-75
800 (346)
28
18
15.8812
34-100
Pass
Pass
Fail
Fail
Fail
Pass
Yes/No
Yes
Yes
Pass
Yes/No
Yes
Yes
Pass
Hours
168
252
Fail
Yes/No
Yes
Yes
Pass
Pass
Project Costs
Mechanical………………………………………………………….$1,623.74
Electrical………………………………………………………………$484.64
Machining (Production)……………...………………………………$2,150.00
Research and Development…………………………………………...$563.55
Total Project Cost: $2,671.93
Projected Cost per Thruster: $668.00
Man Hours……………………………………………….……..2116 Hours
For The Future…
•Place thrusters on the Hydroacoustics Inc. ROV named Proteus to test
design characteristics
•Maximize the thrust to weight ratio by reducing the wall thickness of
the light housing
•Maximize the thrust to power consumption ratio by reducing friction
losses in places such as the gearbox
•Use a new motor supplier
•A future RIT MSD project could be an open source ROV design and
these thrusters can be integrated into the design
•Look at modularity in the software and electronics
•Possible uses for land-based and hybrid (land and sea) vehicles
Questions?