A'U'V'

1
A.U.V.

• Emeric Rochford
• Dale Williams
• Bryan Douse
• Ryan Gray

2
Background

• Autonomous underwater vehicles are becoming
  popular in many applications, including oil
  exploration, and marine studies.
• Underwater vehicles are also used to check the
  hulls of large ships for homeland security, and
  maintenance.

Ryan
3
Mission Statement

• Design an Autonomous Underwater Vehicle that is
  stable and can operate at depths up to 30 feet.
• The AUV has to be able to optically locate five
  target bins and drop a payload in each bin.
• After making the deposit, the AUV must navigate
  to an acoustically marked recovery zone and
  surface between a set of marker buoys

Ryan
4
Solution

• Hull constructed from PVC tubing
• Three electric motor driven propellers for
  propulsion and steering
• Linear leveling system for stability control
• Water pressure used for depth sensing
• Optical and acoustic sensing for target detection
• Use HC08 microcontrollers for subsystem control

Ryan
5
External System Overview
Emeric
6
Internal System Overview
Side View
Emeric
7
Internal System Overview
Top View
Emeric
8
Hull Testing
Hull Testing

• Torque 20 ft lbs
• Depth 3.5 ft
• Time Submerged 15 min

No Leaks!
Emeric
9
Hydrodynamic Drag Forces (Fd)
Fd Cd x ? x Ap x (V2 / 2) Where Cd
Coefficient of drag p Density of Seawater Ap
Projected drag area V Velocity of drag
surface
Total Hydrodynamic Drag Force 84.9 N or
187.1 lbm/s2
Emeric
10
Propulsion

• Minimum Requirements
• Torque 1.012 ft lbs
• Power 0.114 hp
• Thrust 1.3 lbs

• Motor Selected
• Graupner Speed 400
• 6 Volts
• Thrust x2 1.32 lbs

Ryan
11
Depth Sensing

• There is a linear relationship between pressure
  and depth.
• The following is the mathematical representation
  of the relationship
• ?P ?h
• ?P ? Pressure Difference
• ? ? Specific Weight of Liquid

Ryan
12
Freescale MPX4250AP Ported Pressure Sensor
Ryan
13
Pressure Sensor Test

• The results of this test show that the MPX4250AP
  will work for our application and provide enough
  resolution with a 1.5 VDC to 4.5 VDC analog
  output to the HC08.

Bryan
14
Electrical Overview

HC08
HC08
6 volt battery
Opto- Isolator
Opto- Isolator
Opto- Isolator
Motor Controller
Motor Controller
Motor Controller
Stability Control System
12 volt battery
Depth Control Subsystem
Stability Control Subsystem
Navigation Control Subsystem
Ryan
15
Depth Control System
Water Sensor
Pressure Sensor
HC08
Opto- Isolator
Depth Motor Driver
Motor
Ryan
Ryan
16
Navigation System
Optical Sensor1
Optical Sensor2
Optical Sensor3
HC08
Opto- Isolator
Opto- Isolator
Motor Controller
Motor Controller
Motor
Motor
Ryan
17
Software Overview Depth Control
Start
SET_DEPTH SEI
LDAA M1_CTRL BPL SD_M1_DIVE
BCLR
PORTT,00000001 NEGA
BRA SD_M1_CONT SD_M1_DIVE
BSET PORTT,00000001 SD_M1_CONT TSTA
BNE SD_M1_SETFULL
INCA SD_M1_SETSPEED LDAB
PWM_STEP MUL STD
M1_PWM_DCYCLE --- LDAA M2_CTRL
BPL SD_M2_FORW
must be negative BSET
PORTT,00000100 ( NEGA
BRA SD_M2_CONT SD_M2_FORW
BCLR PORTT,00000100 ( SD_M2_CONT
TSTA BNE
SD_M2_SETSPEED INCA SD_M2_SETSPEED
LDAB PWM_STEP MUL
STD M2_PWM_DCYCLE CLI

Water Present in hull?
Yes
No
Surface
depth equal to 30?
Yes
No
depth Greater than 30?
No
Yes
Ascend
descend
Ryan
18
Leveling System Design
The leveling system operates by redistributing
weight in the hull of the vehicle. The mechanical
design consist of a motor coupled to a lead screw
with a weigh threaded onto it. The motor can be
commanded to turn clockwise or counter clockwise
to move the mass up and down the hull as needed.
This is the only leveling system that is needed
because the hull is designed in a way that most
of the weight is at the bottom of the vehicle to
stabilize it in the other direction.
Dale
19
Leveling System Control Circuit
The electrical design consists of a potentiometer
with a pendulum on it to sense the angle of tilt
the AUV is at. This signal is than input into
two comparators to determine if the weight should
be moved, and if so what direction.
Dale
20
Sonar Overview

• The sonar receiver operates by containing an
  array of three sonar sensors spaced 30 degrees
  apart. Each of the detectors will output
  independent signals into a microcontroller that
  will than decide what direction to steer the
  vehicle to point it towards the sonar
  transmitter.

Dale
21
Budget
Dale
22
Schedule
Bryan
23
Questions?