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Search And Rescue Robot

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CHAPTER 1

1.1 Introduction

Search and Rescue Robotics is a relatively new research field dealing with systems that

support first response units in disaster missions. Especially mobile robots can be highly valuable

tools in urban rescue missions after catastrophes like earthquakes, bomb or gas explosions or

daily incidents like fires and road accidents involving hazardous materials. The robots can be

used to inspect collapsed structures, to assess the situation and to search and locate victims.

There are many engineering and scientific challenges in this domain. Rescue robots not only

have to be designed for the harsh environmental conditions of disasters, but they also need

advanced capabilities like intelligent behaviours to free them from constant supervision by

operators.

Rescue workers have approximately 48 hours to find trapped survivors, otherwise the

likelihood of finding victims alive drops substantially.Traditionally, such missions have been

performed by human teams, however, disaster environments have been known to be very

difficult to access by rescue workers due to potential presence of asbestos dust, poisonous gases,

hazardous materials, radiation, or extreme temperatures. Robots on the other hand can bypass

the danger and expedite the search for victims immediately. In such a critical situation

technology can make a great help for rescuers .Thus, rescue robots provide a promising solution

to assist rescue workers in many aspects of SAR operations.

For instance, rescue robots can reduce the chance of injury to workers and rescue dogs by

entering unstable structures, increase the speed of response, and through multiple cameras and

sensor fusion, extend the reach of rescue workers to regions that would otherwise have been

inaccessible. In such cases a single robotic solution may be able to provide all the needed

mission critical reconnaissance. A search and rescue robot can have many features. One of the

most important features is the ability to sense the presence of human life. We can include

humidity and temperature sensors for this purpose. Another important feature is to control the

robot remotely and have easy access for navigational purposes. The robot should also be capable

of providing medical attention and first aid kits to the victim stuck in the disaster zone.


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The Search and Rescue robot is no longer a luxury type of robot. Instead it is a resource that can

be used by many. Due to the natural disasters such as earthquakes and tornadoes and various

types of incident involve collapse building, development of Search and Rescue robots are

essential.

1.2 Objective

To complete the project successfully some aim was needed to be made as a guideline and

the objectives of the project are:

a)to build a basic type of Search and Rescue robot that is capable of moving based on the

input given from a remotely accessed control.

b) To build a robot strong and as small as possible and accommodate all the components and

circuitry within the space available on the robot.

c)To include a robotic arm which helps in clearing debris in front of the robot while

navigating and also to lift objects accidentally fallen on the victim in the danger zone. This

robotic arm is capable of holding on to water bottles, first aid kits and other necessary primary

lifesaving tools.

d) To include sensory components such as temperature sensor and also carbon di-oxide

sensor. These are helpful for locating the human beings.

e) To implement wireless control of the robot. The robot can be controlled remotely and be

able to receive input to move and navigate remotely.

f) To use Raspberry Pi 3 mini computer and python programming language to control the

motors and the robotic arm.

1.3 Scope of the project

The function of the scope of the project is to identify the criteria under which each step of

the project has to take place. The scope of this project is to successfully develop a Search and

Rescue robot. The entire scope of the project can be split into many relevant steps and as long as

these steps are achieved the project will be accomplished successfully.

Firstly, we need to develop the base of the robot. This has to be done by building a robot

chassis and suitable motors for movement


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Secondly, the body of the robot has to be mechanically strong to withstand extreme harsh

conditions.

Next task is to combine all the hardware and circuitry and install in the body of the robot.

The robot then needs to be calibrated to assure it works properly by adjusting the inputs and the

corresponding programs.

1.4 Problem statement

In the past two decade it is estimated that the disasters are responsible for about 3 million

death worldwide, 800 million people adversely affected and property damage exceeding 50

billion dollar. The close example is tsunami and earthquakes, which causes buildings to collapse

and is a problem from these disasters. Rescuers will spend a lot of time to search and rescue for

survivors, this is because the risk that the rescuers will face, any mistakes could endanger their

own life. For example unstable ground or floor and collapse structure are extremely dangerous

for the rescuers especially in the case of earthquake after shock. Because of this problem and

risk that will harm the rescuers, the search and rescue operation more often recover dead bodies

than live ones. Hence our aim is to build a rescue robot capable of searching for human beings

alive, provide first aid help if necessary and make arrangements for rescue operations.


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CHAPTER 2

2.1 Open Source Technology

Open source technology is defined as the production and development philosophy of

allowing end users and developers to not only see the source code of software, but modify it as

well.

Although software is not the only product governed by an open source licenses, it is the

most popular, lending itself well to manipulation of its code and add-ons. Open source provides

a transparent platform upon which anyone with the skills to do so can add to the development

and production of the software either for release as a new incarnation of the software for others

to use or for strictly in-house development only.

Open source software is often free to download and use, open source licenses rarely

transfer any ownership of the software to the end user or developer. Open source is not limited

to software. Open source philosophies have been applied to everything from medicine to soft

drink formulas. The result is higher commitment and even cult status among the developers and

users of open source technologies.

Some of the examples of open source hardware technology are a) Arduino, open-source

microcontroller board, b)OpenRISC – The aim of the OpenRISC project is to create free and

open source computing platforms, c)The Bus pirate – Universal bus interface and programmer,

d)Raspberry pi - Raspberry Pi is a small, single-board computer developed for computer science

education. A United Kingdom (UK) charitable organization called the Raspberry Pi Foundation

developed the device, e) Nitrokey – USB key for data- and email-encryption and strong

authentication etc.

For our project we selected Raspberry Pi 3-the latest model of Raspberry Pi because of

itsease of usage and availability. Also the memory for operation and the clock speed of

raspberry technology are much higher compared to other open source technology.


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2.2 Raspberry Pi 3

The Raspberry Pi is the work of the Raspberry Pi Foundation, a charitable organisation

founded in 2009. It's supported by the University of Cambridge Computer Laboratory and tech

firm Broadcom, the latter of which makes the system-on-a-chip that powers the device. It is a

series of credit card sized single board computers developed in UK by the Raspberry Pi

foundation. Several generations of raspberry pi have been released. In our project we’ve used

Raspberry pi 3 model B. The Raspberry Pi 3 uses a Broadcom BCM2837 SoC (System on Chip)

with a 1.2 GHz 64-bit quad-core ARM CORTEX-A53 processor, with 512 KB shared L2 cache.

Before going into the details on the specifications of raspberry pi 3, let us see the

comparison between each of the model of raspberry pi and choose the better one [1],

fig 2.1: Comparison of Different generations of raspberry pi


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The model of Raspberry pi used in this project is Raspberry Pi 3. Raspberry Pi 3 is a third

generation raspberry pi with the following specifications,

• A 1.2GHz 64-bit quad-core ARMv8 CPU

• 802.11n Wireless LAN

• Bluetooth 4.1

• Bluetooth Low Energy (BLE)

• 1GB RAM

• 4 USB ports

• 40 GPIO pins

• Full HDMI port

• Ethernet port

• Combined 3.5mm audio jack and composite video

• Camera interface (CSI)

• Display interface (DSI)

• Micro SD card slot (now push-pull rather than push-push)

• VideoCore IV 3D graphics core

The Raspberry Pi 3 is equipped with 2.4 GHz Wi-Fi 802.11n and Bluetooth 4.1 in addition to

the 10/100 Ethernet port. For older models the 128MB was allocated for GPU (graphical

Processing unit) and 128 was for CPU. In the newer model B 512 MB was available with the

following split 256 MB, 128MB and 16MB video RAM. Raspberry pi 3 has 1GB RAM.

The Raspberry Pi may be operated with any generic USB computer keyboard and mouse.

The video controller is capable of standard modern TV resolutions, such as HD and full HD and

higher or lower monitor resolutions and older standard CRT TV resolutions.

https://en.wikipedia.org/wiki/Computer_keyboard

https://en.wikipedia.org/wiki/Mouse_%28computing%29


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fig 2.2: Raspberry pi 3 layout diagram

The operation frequency specified in the hardware is 1100 MHz ARM, 550 MHz

core, 500 MHz SDRAM and 6 overvolt (helps in overclocking the raspberry pi 3 for better

performance). However in system information CPU speed will appear as 1200 MHz, when in

idle the speed lowers to 600 MHz

The Raspberry Pi does not come with a real-time clock, which means it cannot keep track

of the time of day while it is not powered on. Now we need to realise how we use this piece of

hardware to build and control a Search and Rescue robot. The main idea is to use certain pins

called GPIO (general purpose input output) pins for our use. Using these pins we can control the

Pulse Width Modulation (PWM), explained better in the next section. [1]


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2.3 GPIO pins

GPIO pins abbreviates to General Purpose Input Output pins. General-purpose

input/output (GPIO) is a generic pin on an integrated circuit whose behaviour—including

whether it is an input or output pin—is controllable by the user at run time. [2]

GPIO pins have no predefined purpose, and go unused by default. The idea is that

sometimes a system integrator who is building a full system might need a handful of additional

digital control lines—and having these available from a chip avoids having to arrange additional

circuitry to provide them.For the interfacing of the Raspberry pi with outside actuators we can

use these pins on the Raspberry Pi. These pins can be interfaced with input or output devices and

programmed to work according to the required application.

Working of the GPIO pins:

Let us consider a simple led connected to a switch and battery as shown below. When the

switch is closed, the led glows and by varying voltage of the battery we can control the intensity

of the led. The GPIO pin works as combination of battery with the switch.

fig 2.3: turning on LED with a switch

By connecting the Led to the GPIO pin, we can control the intensity by changing the duty

cycle of the pulse that is given to the pin which in turn controls the switching on and off or

varying the intensity of the led.We can interface motors, LEDs,sensors etc. to the GPIO pins and

control them.


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The GPIO pins available in Raspberry Pi 3 are shown in the diagram below,

fig 2.4: GPIO pin layout of raspberry pi 3

[2] Like most of the microprocessors have pins with Dual functions, even the GPIO pins

of the Raspberry Pi also has certain pins which are used for dual functions.

It has voltage pins of 3.3V and 5 V which can be used to power external modules. It has 8

ground pins which can be used to ground the devices attached to the Pi.

26 pins are GPIO pins out of which few of them have dual functions like transmission,

receiving, clocks etc.


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For our use we utilize the GPIO pins from the Raspberry pi to interface the motors and

the 5V pins are used for enabling the motor Drivers and one of the servo motors.

2.4 Pulse Width Modulation

Pulse Width Modulation, or PWM, is a technique for getting analog results with digital

means. Digital control is used to create a square wave, a signal switched between on and off.

This on-off pattern can simulate voltages in between full on (5 Volts) and off (0 Volts) by

changing the portion of the time the signal spends on versus the time that the signal spends off.

The duration of "on time" is called the pulse width. To get varying analog values, you change, or

modulate, that pulse width. If you repeat this on-off pattern fast enough with an LED for

example, the result is as if the signal is a steady voltage between 0 and 5v controlling the

brightness of the LED.

Duty cycle is generally defined as the percentage of the pulse that is in on state or high

voltage state out the total time period of the pulse. Duty Cycle = (time the pulse is on / total time

period of the pulse)

fig 2.5 : Duty cycle

Considering the figure shown above has a total time period of 1ms, for 50% duty cycle,

the pulse should be on for 0.5ms, for 25% duty cycle, the pulse should be on for 0.25ms andfor

75% duty cycle, the pulse should be on for 0.75ms

This concept is mainly used in our project for the controlling of the servo motors present in the

arm. The specifications of the servo motors includes the pulses that should be given in order to

rotate the motor 0 to 180 degrees.


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By using the pulse width modulation and concept of duty cycle we can position the servo motor

at angle that we desire thereby giving more precision in positioning of the arm.

2.5 Powering and Accessing

The Raspberry Pi 3 can be powered via the mini-USB connection, using either a battery

or an AC to DC power supply. The power supply can be connected to the board by a mini-USB

port designed specifically for powering up the Raspberry pi. The raspberry pi 3 can be powered

up by a DC 5V, 2A supply.

In this project we make use of Raspberry Pi by interfacing the required hardware to the

GPIO pins of the Pi and program the pins to behave in a certain way. The programming is

written in the Python IDE which is pre- installed in the operating system (Raspbian). The

program can be executed and the controls of GPIO pins can be made use of using ‘Terminal’ in

raspbian.


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CHAPTER 3

3.1 Circuit Analysis

Now that we have selected what version of raspberry pi we are using for this project, let

us see on how do we connect and interface the motors and servo for our needs using different

circuit and programming.

Block diagram

fig 3.1-Block diagram of Search and Rescue robot

The signal for the rotation of the motor is given from the raspberry pi to the IC L293D

which in turn gives the signal to the motors to turn according instruction given in the code. Each

IC can control 2 motors, hence 2 IC’s are used in the circuit. The signal pins of the IC is

interfaced with the GPIO pins of the Raspberry pi.

The robotic arm is made of 4 servo motors to provide 4 degrees of freedom. Each servo

has 3 pins, positive, ground and a signal pins. For controlling the servo motor the signal pins are

interfaced with raspberry pi’s GPIO pins through which the duty cycle is passed to the Servo

motor. In order to limit the current, the GPIO pins and the signal pins are connected through a

1k ohm.


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3.2 Flow of control for DC motors

A key is pressed in the keyboard which is interpreted by the raspberry pi. According to

the key pressed a certain function is executed.

Considering the following example of code snippet,

motor1_in1_pin = 4

motor1_in2_pin = 17

io.setup(motor1_in1_pin, io.OUT)

io.setup(motor1_in2_pin, io.OUT)

motor1 = io.PWM(4,100)

motor1.start(0)

motor1.ChangeDutyCycle(0)

The above code is used to let the raspberry pi know which pins of the GPIO is connected to

which signals of the motor. In the above shown code, the motor1 pins are interfaced to the

GPIO4 and GPIO17 pins and set as output pins. The motor pin is made a PWM pin. The pulses

sent is of 100Hz frequency and the initial duty cycle is set at 0 so that the motor is at stand still

state at the initial condition.

Each of the motor is interfaced and to different GPIO pins with the same initial conditions.

The above code is for one certain motion of the dc motors, now let us see the explanation for

each of the motion such as forward, reverse and steering.


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FORWARD:

def motor_forward():

io.output(motor1_in1_pin, True)

io.output(motor1_in2_pin, False)











The above shown code snippet is used for running all the four motors in the forward direction.

As explained in the working of the DC motors, if the input1 is provided with 1 or True and

input2 is provided with 0 or False the DC motors all rotate in the same direction. Therefore

when the above code is run, all the four motors turn in the same direction carrying the robot

forward with it.

When the key “W” is pressed in keyboard, the raspberry pi automatically initiates the forward

motion of the robot by giving the appropriate signal.


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REVERSE:

def motor_reverse():













The above shown code snippet is used for running all the four motors in the reverse direction.

As explained in the working of the DC motors, if the input1 is provided with 0 or False and

input2 is provided with 1 or True the DC motors all rotate in the same direction. Therefore when

the above code is run, all the four motors turn in the same direction carrying the robot reverse

with it.

When the key “S” is pressed in keyboard, the raspberry pi automatically initiates the reverse



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LEFT:

def motor_left():













The above shown code snippet is used for turning the motor towards the left. For turning the

motor left, the motors in the front end of the robot is put in IDLE state by setting both the inputs

of the motor to false and 0. The rear motors will be given such that the left end motor will rotate

in reverse direction and the right end motor will rotate in forward direction so that it takes a left

turn

When the key “A” is pressed in keyboard, the raspberry pi automatically initiates the left turn

motion of the robot by giving the appropriate signal


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RIGHT:

def motor_right():













The above shown code snippet is used for turning the motor towards the left. For turning the

motor left, the motors in the front end of the robot is put in IDLE state by setting both the inputs

of the motor to false and 0. The rear motors will be given such that the right end motor will

rotate in reverse direction and the left end motor will rotate in forward direction so that it takes a

right turn

When the key “D” is pressed in keyboard, the raspberry pi automatically initiates the right turn



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STOP:

Since we need slow and steady operation of the robot, we need to be able to stop the motor as

when required. So we need to include a stop function too.

def motor_stop():









The above function makes all the input pins of all the motors set to False or 0 making the motors

in hi impedance state and in IDLE state causing the motor to stop.

When the key “Q” is pressed in keyboard, the raspberry pi automatically stops all the motors and

thereby stops the motion of the robot.


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3.3 Flow of control for servo motors

The servo motors in the robotic arm are also controlled by giving signal from the

keyboard. Here we use 4 servo motors for 4 degree of freedom.

As explained earlier, there are 4 servo motors used in the arm. In order to control the precise

rotation of the arm, we need to be able to control each motor individually. So we program

various keys in the keyboard to access different servo motors.

io.setmode(io.BCM)

io.setup(18, io.OUT)

pwm = io.PWM(18,50)

pwm.start(5)

The above code sets the GPIO pin of the raspberry pi to PWM so that we can send duty cycle to

the required servo motor.

def forward(du):

temp=du+0.5

du=temp

print(du)

return du

def reverse(du):

temp=du-0.5

du=temp

print(du)

return du


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The above code is used to increase or decrease the duty cycle of the pulse sent to the

servo motor. When the duty cycle is to be increased the forward function is called. While for the

decreasing the duty cycle the reverse function is called.

When the key “M” is pressed in keyboard, the raspberry pi automatically sends increasing duty

cycle to the servo motor.

When the key “N” is pressed in keyboard, the raspberry pi automatically sends decreasing duty

cycle to the servo motors.

These functions can only increase or decrease the duty cycle but cannot control which servo to

be accessed.

Accessing Different Servos:

BASE:

When the key “U” is pressed in keyboard, the raspberry pi accesses the Base servo motor.

pwm.ChangeDutyCycle(rem1)

Here pwm is a reference to the servo that is connected to GPIO pin of the raspberry pi which is

connected to the signal pin of first or base motor. By increasing or decreasing the duty cycle, the

base can be rotated towards left or right.

ARM:

When the key “I” is pressed in keyboard, the raspberry pi accesses the ARM servo motor.

pwm1.ChangeDutyCycle(rem2)

Here pwm1 is a reference to the servo that is connected to GPIO pin of the raspberry pi which is

connected to the signal pin of servo in the arm. By increasing or decreasing the duty cycle, the

arm can lifted up or down

Clamp Rotation:


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When the key “O” is pressed in keyboard, the raspberry pi accesses the servo for Clamp

rotation.



connected to the signal pin of the Clamp rotation. By increasing or decreasing the clamp can be

rotated towards left or right.

Clamp :

When the key “P” is pressed in keyboard, the raspberry pi accesses the clamp.



connected to the signal pin of the Clamp. By decreasing or increasing of the duty cycle we can

control the opening and closing of the clamp.

All the Pwm pins should be stopped before the termination of the program as shown in the code

below.

For ending the program, the function cleanup() is used. This helps to terminate the program in a

proper manner.

pwm.stop()

pwm1.stop()

pwm2.stop()

pwm3.stop()

io.cleanup()


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CHAPTER 4

Hardware Components

4.1 Geared DC Motors [3]

DC Motors convert electrical energy (voltage or power source) to mechanical energy

(produce rotational motion). They run on direct current. The Dc motor works on the principle of

Lorentz force which states that when a wire carrying current is placed in a region having

magnetic field, than the wire experiences a force. This Lorentz force provides a torque to the

coil to rotate.

Geared DC motors can be defined as an extension of DC motor. A geared DC Motor has

a gear assembly attached to the motor. The speed of motor is counted in terms of rotations of the

shaft per minute and is termed as RPM. The gear assembly helps in increasing the torque and

reducing the speed. Using the correct combination of gears in a gear motor, its speed can be

reduced to any desirable figure. This concept where gears reduce the speed of the vehicle but

increase its torque is known as gear reduction.

fig 4.1-Geared dc motor


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The lateral view of the motor shows the outer protrudes of the gear head. A nut is placed near

the shaft which helps in mounting the motor to the other parts of the assembly.

fig 4.2-shaft of dc motor

Also, an internally threaded hole is there on the shaft to allow attachments or extensions such as

wheel to be attached to the motor.

The search and rescue robot has many components mounted on top of it, naturally the

load on the wheels increases and the required torque will be much higher. Hence it is almost

ideal to use geared motors for better torque. We use 4 dc geared motors for a 4 wheel drive

system of the following specifications,

Table 4.1-dc motor specifications


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4.2 Servo motors [3]

Servo motors have been around for a long time and are utilized in many applications.

They are small in size but pack a big punch and are very energy-efficient. These features allow

them to be used to operate remote-controlled or radio-controlled toy cars, robots and airplanes.

Servo motors are also used in industrial applications, robotics, in-line manufacturing,

pharmaceutics and food services.

The servo circuitry is built right inside the motor unit and has a position able shaft, which

usually is fitted with a gear (as shown below). The motor is controlled with an electric signal

which determines the amount of movement of the shaft.

fig 4.3-Servo motor with position able shaft

To fully understand how the servo works, you need to take a look under the hood. Inside

there is a pretty simple set-up: a small DC motor,potentiometer, and a control circuit. The motor

is attached by gears to the control wheel. As the motor rotates, the potentiometer's resistance

changes, so the control circuit can precisely regulate how much movement there is and in which

direction. [5]

fig 4.4-inside of a servo motor

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When the shaft of the motor is at the desired position, power supplied to the motor is stopped. If

not, the motor is turned in the appropriate direction. The desired position is sent via electrical

pulses through the signal wire. The motor's speed is proportional to the difference between its

actual position and desired position. So if the motor is near the desired position, it will turn

slowly, otherwise it will turn fast. This is called proportional control. This means the motor will

only run as hard as necessary to accomplish the task at hand.

How is the servo controlled?

Servos are controlled by sending an electrical pulse of variable width, or pulse width

modulation (PWM), through the control wire. There is a minimum pulse, a maximum pulse, and

a repetition rate. A servo motor can usually only turn 90 degrees in either direction for a total of

180 degree movement. The motor's neutral position is defined as the position where the servo

has the same amount of potential rotation in the both the clockwise or counter-clockwise

direction. The PWM sent to the motor determines position of the shaft, and based on the

duration of the pulse sent via the control wire; the rotor will turn to the desired position. The

servo motor expects to see a pulse every 20 milliseconds (ms) and the length of the pulse will

determine how far the motor turns. For example, a 1.5ms pulse will make the motor turn to the

90-degree position. Shorter than 1.5ms moves it to 0 degrees, and any longer than 1.5ms will

turn the servo to 180 degrees.

fig 4.5-variable pulse width control servo position

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When these servos are commanded to move, they will move to the position and hold that

position. If an external force pushes against the servo while the servo is holding a position, the

servo will resist from moving out of that position. The maximum amount of force the servo can

exert is called the torque rating of the servo. Servos will not hold their position forever though;

the position pulse must be repeated to instruct the servo to stay in position.

The robotic arm used in the Search and rescue robot uses different type of servo motors.

Since the robotic arm has 4 degree of freedom we use 4 servo motors. The specifications of

different servo motors are as given below,

Table 4.2: Servo motor types used and their specifications

High torque servo motor find application where we need to lift heavy load, and where we

have light load we can use slightly lesser rating motor. Micro servo motors are the smallest

servo motors capable of producing torque up to 2 kg-cm.

Hence these various servo motors are used in the robotic arm based on the torque

requirements.


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4.3 L293D Motor Driver [3]

L293D is a typical Motor driver or Motor Driver IC which allows DC motor to drive on

either direction. L293D is a 16-pin IC which can control a set of two DC motors simultaneously

in any direction. It means that you can control two DC motorwith a single L293D IC.

The pin diagram of the L293D IC is as follows

fig 4.6-L293D pin diagram

It works on the concept of H-bridge. H-bridge is a circuit which allows the voltage to be

flown in either direction. As you know voltage need to change its direction for being able to

rotate the motor in clockwise or anticlockwise direction, hence H-bridge IC are ideal for driving

a DC motor.

In a single l293d chip there two h-Bridge circuit inside the IC which can rotate two dc motor

independently. Due its size it is very much used in robotic application for controlling DC

motors. Given below is the pin diagram of a L293D motor controller.

There are two Enable pins on l293d. Pin 1 and pin 9, for being able to drive the motor, the pin 1

and 9 need to be high. For driving the motor with left H-bridge you need to enable pin 1 to high.

And for right H-Bridge you need to make the pin 9 to high. If anyone of the either pin1 or pin9

goes low then the motor in the corresponding section will suspend working. It’s like a switch.

http://www.rakeshmondal.info/High-Torque-Motor-Low-RPM-Motor


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fig 4.7-Circuit Diagram For l293d motor driver IC controller

Working of L293D

There are 4 input pins for l293d, pin 2, 7 on the left and pin 15, 10 on the right as shown on the

pin diagram. Left input pins will regulate the rotation of motor connected across left side and

right input for motor on the right hand side. The motors are rotated on the basis of the inputs

provided across the input pins as LOGIC 0 or LOGIC 1.In simple you need to provide Logic 0

or 1 across the input pins for rotating the motor.

L293D Logic Table.

Let’s consider a Motor connected on left side output pins (pin 3, 6). For rotating the motor in

clockwise direction the input pins has to be provided with Logic 1 and Logic 0.


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• Pin 2 = Logic 1 and Pin 7 = Logic 0 | Clockwise Direction

• Pin 2 = Logic 0 and Pin 7 = Logic 1 | Anticlockwise Direction

• Pin 2 = Logic 0 and Pin 7 = Logic 0 | Idle [No rotation] [Hi-Impedance state]

• Pin 2 = Logic 1 and Pin 7 = Logic 1 | Idle [No rotation]

In a very similar way the motor can also operate across input pin 15, 10 for motor on the right

hand side.

The motor driver IChas a 5v regulator 7805. This regulator takes upto 35v input and constantly

provide an output of 5v. For better usage the maximum input to be given to 7805 should not

exceed 12v.

fig 4.8-LM7805 pin out diagram

Pin number 1 and ground act as input while pin 3 and ground act as output. This IC

regulates the outgoing voltage. Here we use this to protect the motor driver board from high

currents and voltage. this regulator limits the voltage to 5v, hence it is advised to use a voltage

regulator.


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4.4 Raspberry Pi camera module

The Raspberry Pi camera module can be used to take high-definition video, as well as

stills photographs. It is a small flexi-cable camera module capable of capturing high definition

videos and still pictures. The module has a five megapixel fixed-focus camera that supports

1080p30, 720p60 and VGA90 video modes, as well as stills capture. It attaches via a 15cm

ribbon cable to the CSI port on the Raspberry Pi. [4]

fig 4.9-raspberry pi camera

The camera works with all models of Raspberry Pi 1 and 2. It can be accessed through the

MMAL and V4L APIs, and there are numerous third-party libraries built for it, including

the Picamera Python library.

http://picamera.readthedocs.org/


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CHAPTER 5

Prototype model and implementation

The final finished product of this project has the following capabilities,

a) forward/reverse and left/right motion with a slightly higher radius of rotation.

b) Wireless control of the robot using infrared wireless keyboard

c) Strong mechanical body fit with aluminium chassis and wooden robotic arm

d) Four degree of freedom for the robotic arm

e) Power saving mode whenever the switch if on yet the motor control is not ON

f) Wireless access to raspberry pi terminal and screen by using VNC server

g) Raspberry pi camera to give video feed for navigation.

h) Low power consumption since we are using components that use only DC supply

i) Efficient programming to control all the motors which in turn define how the robot

works.

j) Robotic arm with the help of claw is capable of removing obstacles.

The Search and Rescue robot is no longer a thing of luxury as this as to be utilized to save

lives. Our project concentrates on building and simulating a prototype model of an urban search

and rescue robot. The prototype model looks as below


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fig 5.1-prototype search and rescue robot


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CHAPTER 6

Estimation and Costing

Table 6.1 - Estimation and costing of the Search and Rescue robot


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CHAPTER 7

7.1 Advantages and Disadvantages

Advantages

a) Search and Rescue robots help in disasters to save lives and reduce property damage

b) Using SAR robot, we can track and locate the human being alive in disaster zone with

accuracy and faster too

c) Often the rescuers themselves get trapped in disaster zone, using the SAR robot would avoid

that.

d) It can be used in terrorist zones to diffuse bombs etc.

e) Strong body lets the SAR hold and clear its way easily

Disadvantages

There will always be a downside to new technologies. Due to increasing costs, rescue robots are

expensive to produce. As a result, only countries that are economically stable will be able to

afford the expenses of developing and maintaining these rescue robots. In 2011, the United

States spent about $879 million in developing these field robots (International federation of

robotics, 2012). These numbers are only projected to continue to steady rise. It is projected that

sales of all kinds of robots for domestic tasks could reach almost 11 million units in the period

2012-2015, with a projected worth of US$ 4.8 billion (International federation of robotics,

2012). According to CBC News Broadcasted Documentary, Remote Control War, autonomous

robots are no longer science fiction anymore (May 2011). This means that the robots

themselves are program to make decisions by themselves. These decisions have been

programmed to act accordingly to the situation. The robot will have the power to make

judgments by itself and this brings controversy. There will always be people against autonomous

robots; however these rescue robots are designed to help us during situation of need.


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7.2 Future Upgrades for current model

The search and robot designed and created is a basic drone capable of locating and

sending message for extraction. As the technology advances the need for upgrade is beneficial

and quite required, hence these are the ideas that can improve the quality of the search and

rescue robot

a) Make the SAR much smaller and lighter

b) Waterproof for underwater rescue operations and fire resistant body in case of fire

emergencies

c) Include CO2 sensors and night vision for better tracking

d) SAR can be implemented in air drones

e) Automation is another huge upgrade

These upgrades are for the future versions of the SAR robots. Even though this is a relativistic

ally new field of science, it has progressed a lot.


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CHAPTER 8

Conclusion

SAR had just been an idea that could’ve been implemented when we started with the

project. Now we’ve tried to incorporate what we’ve learned and put it together to make the idea

into reality. We came across a lot of challenges during the designing and the implementation of

SAR, but we’ve overcome those and created SAR. SAR is now capable of removing obstacle,

move in uneven terrains and also can be controlled remotely so that no human being will be

jeopardized during a rescue mission at the same time we assess the situation before we send

another life into harsh and unstableenvironment. It can also help us to be better equipped if there

is any need to be subjected in such scenarios.

The advantage of using such a system would be mainly to save human lives.


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References

[1]www.en.wikipedia.org

[2]https://www.raspberrypi.org

[3]www.rakeshmondal.info

[4]www.element14.com

[5]www.servodatabase.com

[6]www.instructables.com

http://www.en.wikipedia.org/

https://www.raspberrypi.org/

http://www.rakeshmondal.info/

http://www.element14.com/

http://www.servodatabase.com/

http://www.instructables.com/

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