- - i

SUBMARINE CONTROL SYSTEM

A PROJECT REPORT

Submitted by

IMRAN ALI NAMAZI

In partial fulfilment for the award of the degree

of

BACHELOR OF ENGINEERING

IN

ELECTRICAL AND ELECTRONICS ENGINEERING

KCG COLLEGE OF TECHNOLOGY

ANNA UNIVERSITY: CHENNAI 600 025

April 2005

- - ii

ANNA UNIVERSITY : CHENNAI 600 025

BONAFIDE CERTIFICATE

Certified that this project report “SUBMARINE CONTROL

SYSTEM” is the bonafide work of IMRAN ALI NAMAZI who carried

out the project work under my supervision.

Signature

R. Manoharan

HEAD OF THE DEPARTMENT

Department of E.E.E

KCG College of Technology

Karapakkam

Chennai 600 096

Signature

S Kedarnath

(Supervisor)

LECTURER

Department of E.E.E

KCG College of Technology

Karapakkam

Chennai 600 096

- - iii

ACKNOWLEDGEMENT

I would like to express my sincere thanks to KP Subramanian for

providing me with the perfect opportunity to get into such an immensely

exciting field like submarining. But for his grit and determination that

carried him over the past few years, we would not have made it this far.

Apart from him, I would like to extend my thanks to those people who

have helped me in my learning of software, e-CAD and microcontrollers. In

this regard I am indebted to M.S Vishwanath and Palani.

I would also like to thank the staff in various departments whom I

have consulted not for this project alone but also in the scope of my general

learning. Some who deserve special mention are J Jainthi – Dept of ECE,

Francis Saviour – Dept of CSE, V Vinodh and S.S Ranganathan– Dept of

EEE. I also thank my internal project guide, Mr. S. Kedarnath, for his

encouragement and input.

In the course of doing our project work, we found timely help from

several outsiders to whom I extend my heartfelt thanks. Some of them are

Andre, John P, Nithya S, Raj Kumar and Shantha Kumar Sir.

Without the immense support we had from our families especially in

times of trouble when nothing seemed to be working out, we would have

washed out long ago. To them we owe our deepest gratitude.

- - iv

ABSTRACT

Submarines are considered the cream of defence development. The

amount of engineering that goes into each section is simply astonishing.

They integrate the most cutting-edge technology from every discipline. A

country capable of developing its own submarines has special regard in the

worldwide community.

In the scope of our project we wanted to fabricate, assemble and test a

complete “sea-worthy” scale model with radio control capabilities. This

included the study of a number of control options and immense rigour was

needed to actually making things work in the water.

Once this was completed we wished to try and implement a PC based

control system with enhancements such as instrumentation, echo sounding

for underwater mapping as well as video and audio feedback all seamlessly

integrated through a single comprehensive software solution with remote

microcontroller based control and feedback.

- - v

TABLE OF CONTENTS

Title Page No

ABSTRACT iv

LIST OF TABLES viii

LIST OF FIGURES ix

1.0 Introduction 1

1.1 Problem Definition 2

1.1.1 Need for “Minis” 3

1.1.2 Need for Computers 3

1.1.3 Need for multi stage implementation 3

1.2 Literature Survey 4

1.2.1 Alternatives 5

1.2.2 Reasons for Considering 7

1.3 Proposal 8

1.4 Scope 8

2.0 Lafayette Model (Stage 1) 9

2.1 General Overview 11

2.1.1 Introduction 12

2.1.2 Methodology 13

2.1.3 Diving & Surfacing 14

2.1.4 Power Supply 16

2.1.5 Navigation 18

2.1.6 Design Complexity 19

2.1.7 Indian Scenario 20

- - vi

2.2 Lafayette Assembly 21

2.2.1 Specifications & Materials 21

2.2.2 Assembly Drawings 27

2.2.2.1 Bulkheads 28

2.2.2.2 Control Surfaces 30

2.2.2.3 Linkages 31

2.2.3 Electrical Systems 32

2.2.3.1 Diving – BTS 1 34

2.2.3.2 Propulsion – ESC 36

2.2.3.3 Remote Control 37

2.2.3.4 Power Supply & Charging 37

2.2.4 Testing 38

2.2.4.1 Remote Control 38

2.2.4.2 Trimming 38

2.2.4.3 Diving & Propulsion 38

3.0 Delphi Model (Stage 2)1 39

3.1 Systems Overview 40

3.1.1 Enhancements 41

3.1.2 Software – Development Platform 41

3.2 Software 42

3.2.1 Instruments & Simulation 43

3.2.2 Virtual Joystick 43

3.2.3 Video Input & Snapshots 44

3.2.4 Mapping & Display 44

1 NB: Delphi Model is being presented as a design project. Only software has been built.

- - vii

3.3 Electronics 46

3.3.1 Microprocessor (8051) 47

3.3.2 Communication System 48

3.3.3 Drive Control 48

3.3.4 Servomotors (Rudder, Elevator) 49

3.3.5 Ultrasound 49

- - viii

LIST OF TABLES

Table 2.1: Components for Hull 22

Table 2.2: Components for Tech-Rack 23

Table 2.3: Components for Main Drive 24

Table 2.4: Components for Linkages 25

Table 2.5: Components for Diving System 26

Table 2.6: Overview of Drives 33

Table 3.1: Servomotor Control (PCM) 33

- - ix

LIST OF FIGURES

Fig 2.1 Lafayette Overview 9

Fig 2.2 Techrack – Complete 27

Fig 2.3 Techrack – Fore Section 28

Fig 2.4 Techrack – Aft Section 29

Fig 2.5 Control Surfaces 30

Fig 2.6 Linkages 31

Fig 2.7 Electrical Layout 32

Fig 2.8 Static Diving 34

Fig 2.9 Ballast Tank Switch 34

Fig 2.10 Propeller Motor Mountings 36

Fig 2.11 Battery Packs 37

Fig 2.12 Constant Current (Ni-MH) Charger 37

Fig 3.1 Delphi System - Block Diagram 39

Fig 3.2 Delphi Model – Software 42

Fig 3.3 Delphi Model – Electronics 46

Fig 3.4 Delphi Model – Communications 48

Fig 3.5 Delphi Model – Ultrasound Receiver 50

- 1 -

1.0 Introduction

Submarines are very complex machines. The development time for

each submarine may take many years. They are the ultimate fusion of

diverse fields. Even the construction requires enormous dry docks and

caterpillar trucks. Feats are even performed in logistics to bring these

mammoth creatures to life. Submarines are vital to a country’s defence.

Underwater and unknown to enemy navies, they aid in the protection of

surface fleets especially Carrier Groups and Convoys.

Just a few areas of technology where they touch upon are: Hydraulics,

Power Plant Engineering, Hybrid drives, Fluid Mechanics, Instrumentation2,

Communication3, Encryption, GPS, Inertial Navigation, Electronics,

Computing – Analyses & Navigation, SONAR4, Recon, Target Motion

Analysis (TMA)5, Countermeasure Deployment, delivering of ballistics

missiles and nuclear weapons.

Needless to mention, the defence industry is most highly productive in

research, development and production. While our area of focus is not

precisely aimed at military application, some systems do overlap. Within

military technology circles itself, submarines are treated with special regard

for their six degrees of freedom, their autonomy unlike aircraft, their recon

capability and their ability to fire tactical missiles.

2 SSXBT – Submarine Expendable Bathythermograph used to measure water temperature at varying depths 3 SSIXS - Submarine Satellite Information eXchange System. 4 TB23 – The US Navy thin–line towed array sonar that is approx 960 feet long. 5 TMA - Determining a target’s course speed and range in order to direct a weapon in its direction.

- 2 -

1.1 Problem Definition

Submarines are developed almost exclusively for use of the Armed

Forces of a country. What we wish to elucidate is the great use of

submarines as an asset in non defence related areas. These would not be on

the same scale as the ones used in the military but rather, would be miniature

models.

Our submarine is intended to be a versatile ROV (wire controlled),

capable of tasks such as de-mining (without endangering crew) as well as

geological survey, which includes sample taking and underwater

topographical mapping in places too small for a conventional submarine. As

an advance scout vehicle, ultra quiet, with sensitive sonar it would give its

Mother Submarine an edge in underwater tactics.

Possible Use

Apart from use with Mother Submarines, these 'Minis' would help in:

De-mining Operations (No crew + Inexpensive)

Geological Survey (Samples + Topography)

Oceanographic Study (Volcanic Activity)

Underwater S&R (Search and Rescue)

Assist Foundation Structure (building of Oil Rigs)

Exploration & Mapping (Underwater caves and mines)

Archaeological (Bullion recovery)

Underwater Nature Study (No ecologic disturbance)

- 3 -

1.1.1 Need for “Minis”

Minis are what we call “Miniature Submarines”. Full Size submarines

cost upwards of a Billion Dollars. Their comprehensive technology is

sometimes complicated even for tech-savvy people. Development of minis

at more affordable costs would enhance a great many fields.

1.1.2 Need for Computers

Some of the areas we wish to deal with are impractical to build

without the systematic use of computers. We wish to build a basic Windows

enabled control system for such a miniature submarine. It would be able to

control its movements based on feedback from it. Hardware on board would

include a GPS module, a Camera, Sonar as well as an underwater

microphone, all integrating with the software in a seamless way that would

try to facilitate the tasking of our model to some of the applications

aforementioned.

1.1.3 Need for multi stage implementation

Not wanting to take up too many things all at once, we decided that it

was first essential to get a working model capable of deploying in the water.

To control this, we decided to go in for simple radio control, available off

the shelf since our focus would be on wire guidance and there was no need

to try and build our own remote control.

- 4 -

1.2 Literature Survey

Since most information relevant to the building of models is hard to

find in the form of written publication, we began to refer to various articles

about submarines and the building of model U-boats on the internet.

Invaluable in our search for information was the Federation of

American Scientists (www.fas.org) and the Internet search engine Google

(www.google.com).

Actual research work for this project began somewhere in the third

semester when the author and his team-mate got together and set about

discussing the various alternatives to building a model submarine.

Understanding the immense need for software as well as electronics

the author set about trying to equip himself with skills in both fields. As

various interesting topics were presented in the different subjects, the two

tried putting ideas together to bring to bear on the solving of the problem

facing them.

This next topic will deal with some of the alternatives considered and

the reasons for choosing the ones undertaken.

- 5 -

1.2.1 Alternatives

Fabrication:

Getting people in India who could make a submarine to our

specifications was really hard. We tried several places but they all wanted to

know how many pieces we wanted to mass-produce. Finally we had to

source the parts from outside the country.

Construction:

Our first problem was in finding a place where we could do the work.

After a good deal of scouting around, we decided that there was no better

place to do the assembly than our own homes. Equipped with power tools,

crazy glue and a soldering iron, we set about assembling the entire system.

Wire guidance:

Initially we wanted to implement wire guidance in our model not

wanting to suffer any loss of agility and performance, and since test

scenarios would only be swimming pools where anchoring wouldn’t be a

problem, we decided to go in for simple remote control.

Wired Modem:

In the design for a wired PC-uP connection, we first thought of

digitizing all the data (ultrasound, 3 channel audio for triangulation and

video) apart from two way rs232 connection. But the only way we could

think of implementing the bandwidth was to use Ethernet. The AN2019

Ethernet controller was isolated but interfacing it with a standard 8051 soon

became too complex.

- 6 -

Another alternative the author considered was using a USB chip (the

AN2131SC6) with a built in SIE with USB2.0 support. The plan was to

interleave the video with audio in the digitization sequence - audio was four

channel (triangulation plus heterodyned ultrasound). The problem here was

sourcing the chip, since not many development companies in our country

deal with USB and Retailers online talk in terms of MOQ’7s of above 500.

Analog Input:

We finally decided to split the channels, not talk about mass

digitization and use separate carriers for each signal. On the PC side we only

had available output from the mixer as a single channel and could not isolate

line in & microphone into 4 components as was planned. So instead, we

decided that simple recording of sound would be enough and that we would

manually switch the input at the uP side to either sonar or underwater mic.

This also negated the need for a stereo carrier in our RF module.

USB Video versus RF:

Even though analog signals can easily modulate a carrier, the cost of a

video camera module was too much. Also, if composite video is to be fed to

a PC, it would require an additional TV Tuner Card. The total cost of these

two components alone would have been in excess of the rest of the

electronics for this entire design project. USB web camera provided the

easiest solution for this.

6 AN2131SC is made by Cypress Semiconductor (www.cypress.com) 7 MOQ = Minimum Order Quantity

- 7 -

ALP versus C++:

Having never used C++ or ever felt the need, it seemed silly to even

consider writing 8051 source using c++. No two compilers work the same

and coding assembly should be simpler. Familiar with the IDE8 concept, the

author set about trying to find one for 8051 ALP.

Actual Design versus Copy Paste:

As already spoken about, the author has spent some time in learning

to design and develop circuits. It is much easier to tailor circuits to actual

design requirements in the search for design optimization than to take more

complex circuits and modify it.

The DIY approach to PCB fabrication:

The author has never used another person’s layout in any of his design

projects. To give you an idea of some of the projects built by him, kindly

visit the website www.angelfire.com/rock3/ivy/projects

1.2.2 Reasons for Considering

Having just outlined some of the design options and mentioned the

reasons for abandoning or adopting certain ideas, the author is sure that the

design considerations taken into account can all be easily justified. Any

further choices will be presented in those specific sections.

8 IDE = Integrated Development Environment (refers to the workspace of programming tools)

- 8 -

1.3 Proposal

As per our two stage implementation plan, we first set out to make out

submarine ready for testing in an actual water body. The only reason for not

wanting to go inside a lake is that the propeller may easily get damaged and

keeping a birds-eye view on the submarine becomes difficult when the water

is not clear.

The Lafayette model was successfully deployed in an actual

swimming pool on the 9th of April. We had total control over buoyancy as

well as forward and reverse propulsion. There was no failure of any of the

electrical systems on board and we were able to carry on testing until

batteries ran out. The hull and bayonet lock also withstood the maximum

pressure at the bottom of the pool for about five minutes.

The second part of our project is to try to design and/or develop some

of the controls that would actually go into a two-way PC based control

system.

1.4 Scope

Any further development is beyond the scope of this project and

cannot be carried out without access to proper lab facilities and fabrication

industries. In our endeavours we have been successful.

- 9 -

2.0 Lafayette Model (Stage 1)

(Fig 2.1 – Lafayette Overview)

This is a drawing of the submarine model we have assembled, fitted,

and tested. Our first challenge was to build a craft actually capable of diving

and manoeuvring operations. We now wish to rebuild some of the controls

to make our model controllable through software.

At first glance it would seem like the building of model submarines

seems like Childs play. What we intended to demonstrate here was the need

for our country to take seriously the development of these engineering

marvels that would prove on the global level our competence and skill in

ALL engineering fields.

- 10 -

As anybody who has ever built working scale models will tell you, to

make anything actually capable of proper operation is no easy task. To get

the sections outlined in this (second) chapter working properly alone took us

nearly two and a half months.

Fortunately the plans for the enhancements (the Delphi Model) were

taking place simultaneously over the course of the entire fabrication of the

first stage and are therefore being included in this report.

The author of this report therefore wishes to present this second stage

as a complete Design project with each component analysed and alternatives

considered along with preliminary designs for all electronics and software

systems. This will form the contents of chapter 3.

- 11 -

2.1 General Overview

On the NAUTILUS men's hearts never fail them.

No defects to be afraid of, for the double shell is as firm as iron,

no rigging to attend to, no sails for the wind to carry away;

no boilers to burst, no fire to fear, for the vessel is made of iron, not of wood;

no cove to run short, for electricity is the only power;

no collision to fear, for it alone swims in deep water;

no tempest to brave, for when it dives below the water, it reaches absolute

tranquility.

That is the perfection of vessels.

JULES VERNE

TWENTY THOUSAND LEAGUES UNDER THE SEA, 1869

The submarine is considered a pinnacle in engineering design, which

incorporates synergism in every aspect from Mechanical engineering to

Weapons engineering. Submarines are made and exported by an elite group

of countries. These underwater boats have the near mythical ability to stay

underwater indefinitely and lurk in the enemy’s backyard unknown to them

and, if the situation arises, the ability to deliver nuclear weapons. The

submarines are stealthy by nature they have many military and civilian

applications. India does not export submarines; its only indigenous project

was the Shishukumar series of nuclear submarines, which was inherently a

failure. The reason for this failure was attributed to the fact that most Indian

systems are a by-product of reverse engineering. Countries with their own

submarine building capability represent the cream of engineers and facilities,

as this vehicle demands the very best in accuracy, precision, and surety.

- 12 -

2.1.1 Introduction

Submarines are considered machines of war true but they are also used

in peacetime applications. Applications like underwater mineral detection

and mining rescue operations, research, mine detection, underwater mapping

for ships etc. Submarines are highly capricious they need perfection in every

aspect of their operation, as there is no room for error 3000 feet underwater.

Although cost prohibitive they have many advantages they are generally

very silent and non-polluting. This paper is going to look at plans to create

and run a working model submarine. The nature of control here is radio

control and if succeeded represents a first in the undergraduate history of

Tamil Nadu in creating and running of an underwater vessel.

OBJECTIVES

1. To create and demonstrate effectiveness of design for underwater vessels.

2. Increase awareness of need for better defence technology in our nation.

3. To demonstrate the importance of stealth in underwater manoeuvres.

4. To highlight the need for various disciplines like Instrumentation, Power

Electronics, Microcontrollers, Control Systems, DSP and

Communication in complex projects such as the building of submarines,

and how development in such areas would significantly increase the

capabilities of our engineering industry.

- 13 -

2.1.2 Methodology

Submarines have a separate terminology of their own. The following

paragraphs illustrate the basic working principle and terminologies

associated with it.

Submarines are incredible pieces of technology. Not so long ago, a naval

force worked entirely above the water; with the addition of the submarine to

the standard naval arsenal, the world below the surface became a

battleground as well. The adaptations and inventions that allow soldiers to

not only fight a battle, but also live for months or even years underwater are

some of the most brilliant developments in military history.

In this, you will see how a submarine dives and surfaces in the water,

how life support is maintained, how the submarine gets its power, how a

submarine finds its way in the deep ocean, and how submarines might be

rescued.

- 14 -

2.1.3 Diving & Surfacing

A submarine or a ship can float because the weight of water that it

displaces is equal to the weight of the ship. This displacement of water

creates an upward force called the buoyant force and acts opposite to

gravity, which would pull the ship down. Unlike a ship, a submarine can

control its buoyancy, thus allowing it to sink and surface at will.

To control its buoyancy, the submarine has ballast tanks and

auxiliary, or trim tanks that can be alternately filled with water or air (see

animation below). When the submarine is on the surface, the ballast tanks

are filled with air and the submarine's overall density is less than that of the

surrounding water. As the submarine dives, the ballast tanks are flooded

with water and the air in the ballast tanks is vented from the submarine until

its overall density is greater than the surrounding water and the submarine

begins to sink (negative buoyancy). A supply of compressed air is

maintained aboard the submarine in air flasks for life support and for use

with the ballast tanks. In addition, the submarine has movable sets of short

"wings" called hydroplanes on the stern (back) that help to control the angle

of the dive. The hydroplanes are angled so that water moves over the stern,

which forces the stern upward; therefore, the submarine is angled

downward.

- 15 -

Buoyancy in a submarine

To keep the submarine level at any set depth, the submarine maintains

a balance of air and water in the trim tanks so that its overall density is equal

to the surrounding water (neutral buoyancy). When the submarine reaches

its cruising depth, the hydroplanes are levelled so that the submarine travels

level through the water. Water is also forced between the bow and stern trim

tanks to keep the sub level. The submarine can steer in the water by using

the tail rudder to turn starboard (right) or port (left) and the hydroplanes to

control the fore-aft angle of the submarine. In addition, some submarines are

equipped with a retractable secondary propulsion motor that can swivel

360 degrees.

When the submarine surfaces, compressed air flows from the air

flasks into the ballast tanks and the water is forced out of the submarine until

its overall density is less than the surrounding water (positive buoyancy)

and the submarine rises. The hydroplanes are angled so that water moves up

over the stern, which forces the stern downward; therefore, the submarine is

angled upward. In an emergency, the ballast tanks can be filled quickly with

high-pressure air to take the submarine to the surface very rapidly.

- 16 -

2.1.4 Power Supply

Nuclear submarines use nuclear reactors, steam turbines and

reduction gearing to drive the main propeller shaft, which provides the

forward and reverse thrust in the water (an electric motor drives the same

shaft when docking or in an emergency).

Submarines also need electric power to operate the equipment on

board. To supply this power, submarines are equipped with diesel engines

that burn fuel and/or nuclear reactors that use nuclear fission. Submarines

also have batteries to supply electrical power. Electrical equipment is often

run off the batteries and power from the diesel engine or nuclear reactor is

used to charge the batteries. In cases of emergency, the batteries may be the

only source of electrical power to run the submarine.

A diesel submarine is a very good example of a hybrid vehicle. Most

diesel subs have two or more diesel engines. The diesel engines can run

propellers or they can run generators that recharge a very large battery bank.

Or they can work in combination, one engine driving a propeller and the

other driving a generator. The sub must surface (or cruise just below the

surface using a snorkel) to run the diesel engines. Once the batteries are fully

charged, the sub can head underwater. The batteries power electric motors

driving the propellers. Battery operation is the only way a diesel sub can

actually submerge. The limits of battery technology severely constrain the

amount of time a diesel sub can stay underwater.

- 17 -

Because of these limitations of batteries, it was recognized that

nuclear power in a submarine provided a huge benefit. Nuclear generators

need no oxygen, so a nuclear sub can stay underwater for weeks at a time.

Also, because nuclear fuel lasts much longer than diesel fuel (years), a

nuclear submarine does not have to come to the surface or to a port to refuel

and can stay at sea longer.

Nuclear subs and aircraft carriers are powered by nuclear reactors that

are nearly identical to the reactors used in commercial power plants. The

reactor produces heat to generate steam to drive a steam turbine. The turbine

in a ship directly drives the propellers, as well as electrical generators. The

two major differences between commercial reactors and reactors in nuclear

ships are:

• The reactor in a nuclear ship is smaller.

• The reactor in a nuclear ship uses highly enriched fuel to allow it to

deliver a large amount of energy from a smaller reactor.

- 18 -

2.1.5 Navigation

Light does not penetrate very far into the ocean, so submarines must

navigate through the water virtually blind. However, submarines are

equipped with navigational charts and sophisticated navigational equipment.

When on the surface, a sophisticated global positioning system (GPS)

accurately determines latitude and longitude, but this system cannot work

when the submarine is submerged. Underwater, the submarine uses inertial

guidance systems (electric, mechanical) that keep track of the ship's motion

from a fixed starting point by using gyroscopes. The inertial guidance

systems are accurate to 150 hours of operation and must be realigned by

other surface-dependent navigational systems (GPS, radio, radar, and

satellite). With these systems onboard, a submarine can be accurately

navigated and be within a hundred feet of its intended course.

To locate a target, a submarine uses active and passive SONAR

(sound navigation and ranging). Active sonar emits pulses of sound waves

that travel through the water, reflect off the target, and return to the ship. By

knowing the speed of sound in water and the time for the sound wave to

travel to the target and back, the computers can quickly calculate distance

between the submarine and the target. Whales, dolphins, and bats use the

same technique for locating prey (echolocation). Passive sonar involves

listening to sounds generated by the target. Sonar systems can also be used

to realign inertial navigation systems by identifying known ocean floor

features.

- 19 -

2.1.6 Design Complexity

Submarines are immensely complex machines and development may

cost anywhere between $500 million to 1.5 Billion Dollars U.S.

Just to give you an idea about design complexity, the actual systems

on board the US Navy Seawolf9(SSN-21) have been represented in section

(a) of Appendix 1: Colour Illustrations.

The Seawolf has the highest tactical speed of any US submarine.

Tactical speed is the speed at which a submarine is still quiet enough to

remain undetected while tracking enemy submarines effectively.

Overall, the Seawolf's propulsion system represents a 75-percent

improvement over the I-688's -- the Seawolf can operate 75 percent faster

before being detected. It is said that SEAWOLF is quieter at its tactical

speed of 25 knots than a LOS ANGELES-class submarine at pier-side.

Seawolf was projected to be the most expensive ever built, with a total

program cost for 12 submarines estimated in 1991 at $33.6 billion in current

dollars.

9 All information regarding SSN 21, including illustrations are taken from the official website of the Federation of American Scientists at the link: http://www.fas.org/man/dod-101/sys/ship/ssn-21.htm. More information about the same submarine can be found as http://www.ssn21.com/

- 20 -

2.1.7 Indian Scenario

India owns the Foxtrot and Kilo class submarines. On board NONE of

these do we have RAVs. Apart from this, both the aforementioned classes

have been bought second hand from Russia. That means that the electronics

on board is badly outdated. Our Indian equipment is also incapable of

detecting mines and is built for operation from surface ships.

We have tried to design and part develop a system that brings the

most cost-effective way of combating these various disadvantages faced by

our Armed Forces especially in the field of tactics.

The Americans, to detect and defuse underwater mines expend

torpedoes every time. So tactically, they have to forego a warhead capable of

executing a firing solution each time they wish to neutralize dangerous

waters.

The Russians use the same system which was copied by the

Americans and vice versa. Like the use of Akula design to draft plans for the

Seawolf which was again used by the Russians in developing the Amur

class. This is called sharing of technology.

We wish to further even this system, by making our re-deployable

vehicle capable of setting off mines remotely whereby it ensures distant

triggering and a safe passage for its docking vehicle.

- 21 -

2.2 Lafayette Assembly

In this section, we discuss in depth the various aspects that went into

the building of our very own Lafayette Model.

2.2.1 Specifications & Materials

To give you an idea of what we had to begin with, attached here is the

complete list of all the parts we began with and the material of fabrication.

Model Name: SSBN616 LAFAYETTE

Table 2.1: Components for hull

Table 2.2: Components for tech-rack

Table 2.3: Components for Main Drive

Table 2.4: Components for linkages

Table 2.5: Components for Diving System

- 22 -

Part Description Material

HULL

Conning Tower resin

Missile Hatch epoxy

Hull Bow Section epoxy

Hull Aft Section epoxy

Aft Hatch Cover epoxy

Rudder upper resin

Rudder lower resin

Diving Plane Carrier resin

Diving Plane aft resin

Diving Plane conning tower resin

Strip brass

Nut brass

Screw (counter sunk) steel

Bayonet Lock (front) aluminum

Bayonet Lock (aft) aluminum

O-Ring NBR

Ballast lead sheet

Rod steel

Rod brass

Plate plastic

Template plastic

Ballast lead shots

Table 2.1: Components for Hull

- 23 -

TECH RACK

Bulk Head resin

Carrier & Carrier Plate PVC

Rod aluminum

Bracing with thread brass

Screw (machine head screw) steel

Screw (flat machine screw) steel

Lock Nut steel

Tapping Screw steel

Screw (flat machine screw) steel

Tube for Piston Tank aluminum

Tube for Pressure Switch brass

Tube for wire Battery Pack 2 brass

Tube for Pressure Switch wire PVC red

Tube for Pressure Switch wire PVC red

Tube for Antenna PVC red

Tube Connector for Pressure Switch brass

Tubing for Piston Tank PVC transp

Tubing for Pressure Switch PVC transp.

Angled Connector plastic

Contact Tube for Pressure Switch wire brass

Tubing silicone

Tube brass

Wedge 2-pole

Table 2.2: Components for Tech-Rack

- 24 -

MAIN DRIVE

Main Drive Motor 550/5-12V

Motor Mount aluminum

Shaft Sealing Ring rubber

Screw (flat machine screw) steel

Coupling brass

Grub Screw socket-head steel

Prop Shaft VA

Propeller scimitar 6-blade brass

Stop Nut steel

Washer steel

Capacitor tantalum

O-Ring NBR

Stern Shaft Bushing Nylon

Nut VA

Table 2.3: Components for Main Drive

- 25 -

LINKAGES

Bushing for rudders and diving planes brass

Collar brass iø 3

Control Horns (diving planes) brass

Grub Screw VA

Lever for rudders PVC

Screw steel

Washer steel

Clevis steel

Threaded Connector steel

Coupler steel

Control Rods brass

Axle for diving planes brass

Bushing Tube Part brass

Bushing brass

bellow rubber

Axle for rudder (pre-glued) brass

Axle for conning tower diving planes brass

Ball Link brass/plastic

Table 2.4: Components for Linkages

- 26 -

DIVING SYSTEM

Piston Tank TA 825

Ballast Tank Switch BTS 1

Pressure Switch PS 1

Lead for TA control 3-pole

Wire for BTS-PT red

Wire for BTS-PT black

Wire for BTS-PS 1000

Wire for BTS-PS 1000

Wire for PS 2-pole

Heat Shrink Sleeve rubberised

Cable Ties plastic

Table 2.5: Components for Diving System

Outlined above is a complete list of parts received to make all sections

work. We first began to build the tech rack. Once that was completed, we

began to assemble the linkages that control the rudder and elevator. After

that came the fitting of the bayonet lock which alone took 3 tries to get the

working with epoxy resin right. Finally we employed a double seal using 2

kinds of resin – one epoxy based and the other metal paste.

After that came the electrical fitting procedure. These will be dealt

with individually in the sections dealing with the various electrical sub-

systems. These components were used as and when necessary over the entire

course of the project work.

- 27 -

2.2.2 Assembly Drawings

This is the CAD10 drawing of the entire tech rack assembly.

10 ALL CAD drawings are provided courtesy KP Subramanian and Gregor Engel KG.

Fig2.2 - Techrack – Complete

- 28 -

2.2.2.1 Bulkheads

Bulkheads are in two sections – the fore section and the aft section on

either side of the Piston Tank. Each section is designed to carry 10 cells. The

fore has an RF receiver with its own battery pack and a pressure switch11.

11 The Pressure Switch is part of the Diving System and is explained in detail on page 35.

Fig2.3 - Techrack – Fore Section

- 2

9 -

Fig2.4 - Techrack – Aft Section

- 30 -

2.2.2.2 Control Surfaces

Control surfaces are what we required for steering in the lateral and

vertical planes, to give us 6 degrees of freedom. The material is hardened

resin, actuated by brass mountings inside the tail of the submarine.

Fig 2.5 Control Surfaces

In all there are four control surfaces. The rudders are for affecting yaw

and are used in steering. The elevators change pitch and help change depth.

The sail stabilizer is to ensure minimum listing.

- 31 -

2.2.2.3 Linkages

Rods from the servomotors provide only linear motion. These are

converted to precise motion along an arc to move the rudders and the

elevators. For this we used a linkage system outlined below.

Fig2.6 - Linkages

- 32 -

2.2.3 Electrical Systems

An overview of the entire Electrical system is as follows.

Fig2. 7 Electrical Layout

- 33 -

What follows is a table presenting an overview of the various motors

used to drive the corresponding sections.

Part Operation Control

Propeller Speed and Braking DC Motor

Rudder Left-Right (steering) Servomotor

Elevators Move up/down Servomotor

Bow Plane Aids in rapid Diving/Surfacing Solenoid

Sail Stabilizer Stabilizes the motion Servomotor

Piston Tank Controls weight by pumping water in/out DC Motor

Table 2.6 Overview of Drives

- 34 -

2.2.3.1 Diving – BTS 1

In our submarine we have used the simple principle of static diving.

Water is taken in and as weight increases, buoyancy decreases. Thus, as the

piston tank draws water, the submarine sinks deeper in the water.

Fig 2.8 Static Diving

Trimming calculations and piston tank (variable ballast) displacement

gives 6 feet dive depth. Beyond that, underwater distortion of radio waves is

too intense. A 12V DC motor rotates a spindle that moves a piston in and out

of a cylinder. Drive to this motor is through two relays on board the BTS.

Ballast Tank Switch

R1 R2

Fig 2.9 Ballast Tank Switch

- 35 -

The BTS decodes a proportional (=servo) channel12 from the receiver

to a forward-stop-reverse switch function for the Piston Tank motor. When

relay R1 is off, drive to the motor is cut. On half way to either end of the

stick travel, Relay R1 is activated and the Piston Tank motor starts running.

R2 is a regular DPDT wired to reverse direction of the motor.

Switches S1 & S2 act as limit switches and are fed by the pilot shaft

which is coupled to the spindle by a second set of reduction gears.

The switching of the relays takes place after a short delay of about

1/10th of a second to filter short impulses. Also, since the on and off points

of a relay differ a bit (hysteresis), this prevents the relay from flickering.

The Pressure Switch (PS) provides a failsafe of approx. 6 feet. If the

model dives below this level, the BTS will automatically switch to the

"surfacing mode" and empty the Piston Tank. The model will then resurface.

Alternatively, the BTS offers another fail safe device. If the signal is

lost the BTS will switch to "blow" (empty) the Piston Tank.

12 Standard PCM signals for servo motor control will be dealt with in detail in chapter 3.3.2.3

- 36 -

2.2.3.2 Propulsion – ESC

Propulsion is achieved by a powerful 12V DC motor drawing nearly

4A (50W). The motor is fixed on the resin bulkhead and the propeller shaft

is coupled to it after attaching proper bushings and mountings shown in fig.

Fig 2.10 Propeller Motor Mountings

The Electronic Speed Controller drives the propeller. Its input is

standard servo control PCM (1.25 to 1.75mSec) with 1.5mSec as the centre

point (in this case dead stop).

Driving the motor is two pairs of complementary power transistors

similar to the one used in choppers. Reversal of output polarity is done by

turning on the alternate diagonal transistors.

Voltage control is not employed here since the motor is constantly

loaded and efficiency would be aversely affected. Pulsing (or switching) of

the output is done using the power transistors in the output stage.

- 37 -

2.2.3.3 Remote Control

The remote control was a standard four channel Hi-Tech Radio

Control. Receiver power is obtained from the ESC channel (channel 2).

Though the antenna was uncoiled fully, to pick up signals through four feet

of water was hard for a radio used to control model aircraft at 4 km.

2.2.3.4 Power Supply & Charging

The system was designed with 20 rechargeable 3000mAh Ni-MH

Cells, connected to give a capacity of 12V 6000mAh, and divided into 4

packs to fit into slots of the techrack as shown in fig 2.7 (electrical layout).

Fig 2.11 Battery Packs

CHARGING:

To maintain battery life a constant current source was needed. We

modified a 7805 to act as a charger in the following manner.

Fig 2.12 Constant Current (Ni-MH) Charger

I = Vd / R

Vd = 1.6V (LED) R = 100E

.`. I = 160mA

- 38 -

2.2.4 Testing

The final phase of our project was testing. Once assembled and the

hull was checked for integrity with preliminary water testing and deemed

ready for testing, it was our job to try and “deploy it in the water” ASAP.

2.2.4.1 Remote Control

Testing was done in 3 different sections. First we had to hook up all of

the electrical systems and see if everything was in place. To test if the drives

were all proper, we hooked it all up with the radio system.

2.2.4.2 Trimming

Once we had the green light from radio and control, we had to do

trimming. Trimming was done in a small tank of water about 15 inches deep.

It was a painstaking process and took four hours and a sensitive balance to

achieve.

2.2.4.3 Diving & Propulsion

Finally deeming our system ready, we made arrangements to have a

swimming pool available and invited our internal guide to view the

demonstration, taking our baby on its first day out.

Testing was a complete success. We had total control over buoyancy

as well as propulsion. Enclosed with our report is the footage we took of this

incredible event along with various other clips and pictures taken during the

various stages of development.

- 39 -

3.0 Delphi Model (Stage 2)

The Delphi Model is our PC solution for controlling a submarine. The

various systems are outlined here.

Fig 3.1 Delphi System - Block Diagram

- 40 -

3.1 Systems Overview

The control system comprises three basic sections. Control originates

from the software and no computing is done anywhere else in the system.

For rapid development and operational flexibility this is the best option.

The microcontroller section control the various drive mechanisms.

Rudder control, for instance would have only 3 positions and the drive

circuit would require 5V, 3.5V or 6.5V. To keep the instruction file small,

we use our own DACs rather than standard DAC chips. They control the

drives to the motors, tailored to meet each ones working requirements.

Another section is instrumentation. To sense pitch and yaw, angular

displacement will be sensed by readily available compact optical sensor

modules. Depth is perceived by measuring hull stresses using a strain gauge.

A matched pair is used to negate the temperature coefficient of resistance.

The microcontroller, in the actual working environment (on board and

in the water) can be compared with a remote terminal unit in a SCADA

system. All it will have are basic initialisation programs for the USB camera,

stepper control subroutines, and a relaying mechanism for passing on

commands to the various drive circuits.

Though all the various sections of software were designed separately,

controls will all be found in the SAME window. Separate dialog boxes

would only slow down user response and that cannot be afforded in this

situation where we must emulate an RTOS.

- 41 -

3.1.1 Enhancements

By comparison with the Lafayette model, this second stage

implementation would have the following advantages:

On board Instrumentaion

Visual Feedback via camera

Underwater listening/mapping capabilities

Preset travel patterns / courses (autopilot)

Control may be implememted via internet/satellite link.

3.1.2 Software – Development Platform

Our first decision was operating system. Since our system has

commercial single-person-use application for harbours and industrial mining

companies, we chose Windows as the platform for development.

Within that scope, obvious choice of programming language was

visual basic since it provided visually rich user interface, critical for

applications like this and also ease of design and tremendous support online.

Today, the lack of a driving need to design proprietary hardware and

operating systems with the advent of packages like Microsoft Windows CE

and .Net, makes the potential to realize an embedded system very high.

- 42 -

3.2 Software

Fig 3.2 Delphi Model – Software

This is an overview of what has been developed so far. The sound

processing and map drawing development was done in .Net for easier

development but will be integrated into our VB6 solution soon.

- 43 -

3.2.1 Instruments & Simulation

Some of the assumptions made to simulate the submarine and

instruments response was:

Depth: Piston tank motor - 3 seconds = 1 foot dive/rise.

Yaw & Pitch: 30deg * speed/3 = angular displacement / sec

(30deg = preset control angle in control apparatus)

Acceleration: .5 kmph/second (value doubles on sudden reversal)

(negating motor and ESC response time)

Simulation was done using a timer set to trigger every second. Based

on the difference between set point and instrument, the necessary control

signal for each navigational aspect is calculated and sent. This procedure

was critical in designing the control section.

3.2.2 Virtual Joystick

One of the most important aspects of Interface design is to give the

user alternate means of controlling his application. If the menu is the

primary way of accessing functionality, alternates like mnemonics, shortcuts

and toolbars are used.

To give the user access to all the navigational controls in one easy

format, we set about creating a virtual joystick. It is nothing but a

PictureBox where both Keyboard and mouse Input is taken and passed onto

the appropriate instrument using implicit calls.

- 44 -

3.2.3 Video Input & Snapshots

For video input, we have made use of the windows API. The camera

is linked to a PictureBox control by passing its window handle (.hWnd

property) to the capCreateCaptureWindow function of the avicap32.dll.

Then, we begin transmission of data by calling the SendMessage

function of the User32.dll and sending the WM_CAP_CONNECT constant

to the same PictureBox

All this takes place in the “Connect” Command Button. By using a

timer, we can update the frame at any rate. Chosen is five frames per second

Saving to bitmap is done by simply calling the SavePicture method in

the click event for a “Save” command button. Images can easily be retrieved

by using the file system object to enumerate images from the archive. On

screen comparisons with an image library can also be made.

3.2.4 Mapping & Display

Echo-sounding:

For mapping, we need to instruct the microcontroller to emit a short

burst of ultrasound. A function in the module which is constantly analysing

the line input is given the “time of start” parameter. It waits until it detects

an echo and then calculates distance and returns it to the software.

Instrumentation gives current depth and inertial navigation knows the

coordinates. Extrapolating the two, it is easy to find distance to the sea floor.

- 45 -

Scanning sequence:

If only sounding is done, the strip scanned would be too narrow. To

increase this (and reduce the number of passes required by the submarine to

do any decent mapping) it was decided to employ a scanning pattern. The

emitter is mounted on a stepper motor and software knows precisely which

direction the emitter is pointing. In this fashion it would be possible to scan a

wide strip below the submarine.

Choice of View

To display the map information, the simplest way is to use colour

coding for elevation and draw the plan view. This is not only easy for

computation but also from the drawing. This means that the map can easily

be redrawn during mapping operation as the heights at the various

coordinates are known through sounding.

Storage and indexing:

The map is read from a file and buffered to memory in the form of an

array. By defining a new data type to store a point in 3D, we are able to

facilitate easy indexing by coordinates.

Drawing:

On screen, displaying is done by using an array of label controls. This

array is created dynamically at runtime and positioned. A separate method

that returns a specific colour for a given height is created for frequent usage.

- 46 -

3.3 Electronics

The software will generate a format file in the form of a byte string

which will instruct the microcontroller to set things in action. In this fashion,

navigation control as well as scanning sequences for the ultrasound will be

affected on the submarine via microprocessor.

Fig 3.3 Delphi Model – Electronics

- 47 -

3.3.1 Microprocessor (8051)

The 8051 will, as already mentioned, be simply relaying information

to and from the software. The closest to actual computing that will be done

by it is generating the scan sequence for the stepper motor and reading/

writing information to the 8255 for the instrumentation.

The 8255 Programmable Parallel Interface, with 3 ports will be slaved

to the 8051 and will be hooked up to an adc0808 on port A. Port C which

can be used for serial interface, will be used to read the 3byte stream

available from the instruments for pitch & yaw.

The 8051 will also have to send the set points to the various drives.

For the speed controller, a 4 bit setting will be given. Using a weighted

adder circuit, this will be converted to analog. The PCM generator will

decode this 0-10V analog input and control the ESC or the servos.

Microswitches coupled to the Piston Tank will indicate status of the

diving operation. The pressure switch will also be connected to the uP so

that its status can be relayed to the software.

A small analog switch will determine which input (microphone or

ultrasound) is fed to the line in, since software cannot distinguish left and

right channels as is is direct output from the mixer in windows. This means

that listening/mapping is cannot be done simultaneously. The uP also

controls when the emitter transmits.

- 48 -

3.3.2 Communication System

Fig 3.4 Delphi Model – Communications

3.3.3 Drive Control

Propeller:

A 4-bit DAC drives a power transistor that is properly biased to control the

Propeller motor. Reversal is achieved by using a DPDT relay.

Piston Tank:

2 Relays are used here, one to turn the motor on and the other to reverse.

Stepper Motor Control:

Stepper motor is used for the ultrasound scanning sequence. A stepper

motor has two coils each with its centre taken to neutral. Thus it has four

terminals and one common. Each coil is driven using a transistor. The

transistors are controlled by the microcontroller.

- 49 -

3.3.4 Servomotors (Rudder, Elevator)

Signals for controlling servomotors are tabulated as follows.

TON Position

1.5mS 0º

1.5mS 90º

1.5mS 180º

Table 3.1 – Servomotor Control (PCM)

Rudder position will be either centre, left or right. No proportional

steering is required. A 2bit control word from the software will be decoded

to 3 (analog) signal levels using an OpAmp adder.

This analog input will go to the standard PCM encoder circuit that is

used to control the ESC as well. Elevator control is the same except that the

2 bit DAC output corresponds to 15 degrees of elevator position as required.

3.3.5 Ultrasound

Sound propagates forty times further in water than in air. Also, vision

underwater is severely impaired due to turbidity. Therefore, to know what is

around us, we need to use underwater microphones.

A commonly heard of concept to determine range is echo sounding.

We emit a sound and listen for its echo. If the duration of travel is measured,

distance from the source to the reflecting surface can be found out. It is thus

possible to identify range to an object as well as establish the distance to the

bounds of the water body. This is how we do underwater mapping.

- 50 -

For this, we use ultrasonic waves. As they have higher frequency,

attenuation over distances is less than if audible frequency was emitted.

Since no natural source of ultrasound exists underwater, noise is not a factor.

Ultrasonic waves by definition lie ABOVE the audible range. This

means that a detector circuit cannot simply be hooked up to a PC since the

sound card will attenuate frequencies above 20 kHz. So beating of the

reflected wave has to be done to get it in the region of 10 kHz.

The concept of beating or heterodyning is simple. A local oscillator

has a frequency differing from the one to be heterodyned by the desired

output frequency. The two are then mixed. Thus, for example if the received

ultrasound wave was 40 kHz and an output of 10 kHz was required, the local

oscillator would have to produce 30 kHz.

Fig 3.5 Delphi Model – Ultrasound Receiver