Line Following Robot
Team 3
Nguyen Hong Quan (Team leader)
Diep Que Tran
Le Vu Thanh
Technical Writing
Department of English
Vietnamese-German University
14 January 2014
Nguyen Hong Quan
VGU New building
Binh Duong New City,
Vietnam
14 January 2014
Mr. Richard G. Bradley, MAL, MSM
Vietnamese German University
Foundation Year Studies
Nam Kỳ Khởi Nghĩa Street, Hòa Phú Distrrict
Bình Dương New City, Bình Dương Province
Dear Mr. Bradley,
Enclosed is our final report entitled “Line Following Robot” submitted to partially meet the
requirements of the course Technical Writing.
This report describes the design of the Line Following Robot. Each component of the robot
is described and illustrated, and schematics of the circuit design, are included.
I appreciate the time you are taking to review this proposal and hope that it meets your
requirements. If you have any question, feel free to contact me either by telephone 0995185213 or
e-mail: nguyenhongquan_eeit13@hotmail.com
Sincerely yours,
Nguyen Hong Quan (Team leader)
Enclosure: Line Following Robot (1 copy)
Vietnamese-German University
Foundation Year Studies
EE2: Technical Writing
Line Following Robot
Nguyen Hong Quan
Diep Que Tran
Le Vu Thanh
Instructor: Richard G. Bradley, MAL, MSM
Due date: 14 January 2014
Disclaimer
We declare that this report is a product of our own work, unless otherwise referenced. We
also declare that all opinions, results, conclusions and recommendations are our own and may not
represent the policies of opinions of the Department of English or the Vietnamese-German
University.
Nguyen Hong Quan
Diep Que Tran
Le Vu Thanh
i
Abstract
Line Following Robot
Final Proposal
Group 4, 5 – Team 3
Nguyen Hong Quan
Diep Que Tran
Le Vu Thanh
This report describes a proposal for the design, building and testing of a line following robot, which
can start autonomously when a starter gate is removed and raise a flag when it encounters the finish
wall. The course for the robot will be a black line on a light color background. The proposed robot
consists of a set of a small vehicle which runs on two wheels operated by 2 motors, a pair of light
sensors to drive the robot follow the black line course and a lever switch system in front of the robot
to start or stop the robot when necessary as well as to rise the flag by activating a motor used to
move the flag. The robot is powered by Lithium ion battery to increase the speed of motors and is
maximum of 40 cm wide by 50 cm tall. It must also not contain any microprocessor to run. After
this project, we can learn more about the engineering process, new electronic components’ function
and gain experience in designing and building electrical devices.
Keywords: line following, robot, motor, engineering
ii
Acknowledgements
Our team wish to thank Mr. Richard G. Bradley for his instruction. We also received help
during this projects from the following people, they are prior EEIT students: Le Ba Tien Trien,
Nguyen Son Ha and Nguyen Duc Hieu.
In preparing this project, responsibilities were divided up as follows:
Nguyen Hong Quan as the team leader and the writer of Control Circuit. He took mainly
responsibility for searching information on the internet, designing the electrical circuit, building
chassis.
Le Vu Thanh bought components, wrote Abstract, Appendix and did all the soldering.
Diep Que Tran wrote the rest and was responsible to edit this document.
iii
Table of Contents
Disclaimer .......................................................................................................................................... i
Abstract ............................................................................................................................................. ii
Acknowledgements ..........................................................................................................................iii
Table of Contents ............................................................................................................................. iv
List of Figures ................................................................................................................................... v
1. Introduction ................................................................................................................................. 1
1.1 Purpose of the Report ............................................................................................................ 1
1.2 Scope of the Report ............................................................................................................... 1
2. Background ................................................................................................................................. 1
3. Requirement Specification .......................................................................................................... 1
3.1. Functional Requirements ..................................................................................................... 1
3.2. Other Requirements ............................................................................................................. 1
3.3. Constraints ........................................................................................................................... 1
4. Description .................................................................................................................................. 2
4.1. Overview .............................................................................................................................. 2
4.2. The Line-Following ............................................................................................................. 2
4.2.1 Chassis ......................................................................................................................... 2
4.2.2 Gear Box ...................................................................................................................... 2
4.2.3 Wheel System .............................................................................................................. 2
4.2.4 Power Supply ............................................................................................................... 3
4.3. The Flag-Raising.................................................................................................................. 3
4.4. The Control Circuit .............................................................................................................. 3
5. Testing ......................................................................................................................................... 5
6. Conclusion .................................................................................................................................. 5
7. References ................................................................................................................................... 6
Appendices
Appendix A, Glossary of Terms ............................................................................................. A-1
Appendix B, List of Items and Estimated Costs ..................................................................... B-1
iv
List of Figures
Figure 1 Gear System ......................................................................................................................... 2
Figure 2 Control Circuit ..................................................................................................................... 4
v
1. Introduction
1.1. Purpose of the Report
In the course “Technical Writing”, we students were provided knowledge that we could applied in
researching and presenting technical information to a range of audiences. This report, which is in
the form of a formal engineering proposal, was created to meet the requirement for successful
completion of the course “Technical Writing” and discusses the design of the Line-following Robot.
1.2. Scope of the Report
In this report, we discusses about the requirements, design, working mechanism, installation and
testing of a robot that can automatically follow a black line on the ground. After finishing a course,
the robot will encounter the wall and automatically raise a flag.
2. Background
During the course “Technical Writing” we were required to go through the process of designing a
robot and submit all the necessary paperwork. After two and a half months, we finally moved to the
last stage which was to submit this final report and to bring our line following robot to the contest
held in the end of the course.
By carrying out this project, our team aimed to achieve the following objectives: improving
technical writing skill, teamwork skill and soldering skill, learning how to use Eagle to design a
circuit on computer and finally, successfully building a line following robot.
3. Requirement Specification
3.1.
Functional Requirements
We had to build a robot which must be a self-propelled machine. The robot can autonomously start
following a black line on a light colored tile background after a barrier is removed. It is also able to
turn a maximum angle of 45o. At the end of the course, the robot will encounter a wall and it must
autonomously raise a small flag.
3.2.
Other Requirements
The flag is at least 5 cm long by 2.5 cm tall. It must only have “VGU”, written or printed in a
contrasting color on both sides. The rod to which the flag is attached must be in horizontal position
while travelling and after the robot encounters the wall, the rod is raised to the vertical, with the top
of the flag at least 15 cm above the floor.
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3.3.
Constraints
The components of the robot must be available is Vietnam.
The robot has no microcontroller.
The maximum value of power supply is 12V
The height and the width of the robot must be no more than 50 cm and 40 cm respectively
because it must be able to pass through the legs of a standard VGU student chair.
The robot cannot use explosive chemical reactions to produce force.
1
4. Description
4.1. Overview
The robot consists of two parts. The first parts is called Line Following that will give the robot the
ability to detect and follow the black line automatically. The second part is Flag-Raising which will
detect the wall and raise the flag to vertical. All switches were glued to the plastic chassis by using a
glue gun. Others parts were connected to the chassis by screws.
4.2. The Line Following
4.2.1. Chassis
The U-shaped chassis is 22 cm long, 6 cm wide and 1.8 cm high. Three single pole double throw
switches were attached by glue to one end of the chassis and two gear boxes were attached to the
other end by screws.
4.2.2. Gear Box
The gear set consists of two spur gears and three compound gears. Their connection can be seen
from the figure below. The gear ratio is 1:120.
Figure 1 Gear System
4.2.3. Wheel System
The wheel system consists of two front wheels and two rear wheels. Each yellow plastic rear wheel
whose diameter is 6.5 cm was attached to a gear box. The rear wheel was covered by a resin band.
The two white front wheels were placed next to each other and they were attached to the middle of
a metal axis.
2
4.2.4. Power Supply
We used three 3.7V Lithium ion batteries. The Line-Following will use two batteries to have the
voltage of 7.4V and the Flag-Raising will use the other.
4.3. The Flag-Raising
The three switches of the Line-Following were placed 4.5 cm above the floor to detect the wall and
the barrier which is approximately 42 cm long, 10 cm high and is approximately 1 cm above the
floor. Therefore, the vehicle will stop when the switch is pushed by either the wall or the barrier.
The three switches of the Flag-Raising were placed 16 cm above the floor and in parallel to the
switches of the Line-Following to switch on the motor of the Flag-Raising only when the robot
encounters the wall. By providing two different height of two switches, the vehicle will be switch
on or switch off when encountering either the wall or the barrier but only raises the flag when
encountering the wall. The last switch of the second part, which was placed behind the first three
switches of the Flag-Raising, will shut down the Flag-Raising’s motor when the flag pole is vertical
and hits this switch.
4.4. Control Circuit
The control circuit consists of one LM324N op-amp, two 2n3904 NPN transistors, two LDRs, two
LEDs, two 1K resistors, six 10K resistors, three single pole double throw lever switches, two 3.7V
lithium-ion batteries, one single pole single throw toggle switch, two 10K variable resistors, two
DC motors. One LDR and one LED are assembled right next to each other. If the black tape line is
under the LDR and the LED, the light emitted from LED won’t bounce up to the LDR so the
resistance of LDR will be about 50K. If the white floor is under the LDR and LED, the light will
bounce up to the LDR and reduce the resistance of the LDR to about 5K. The LM324N is a quad
op-amp and consists of four op-amps. Pin 4 and pin 11 is use to provide power supply for LM324N,
pin 4 is positive and pin 11 is negative. Pin 1, 7, 8, 14 is used for output signal, pin 3, 5, 10, 12 is
used for non-inverting input signal and pin 2, 6, 9, 13 is used for inverting input signal. If the
voltage at non-inverting pin is higher than the voltage at inverting pin, the output signal will be
positive. If the voltage at non-inverting pin is lower than the voltage at inverting pin, the output
signal will be negative. The non-inverting pin is connected to the LDR and to the negative pole of
the battery through a 10K resistor. The inverting pin is connected to the positive pole of the battery
through a 10K resistor and to the negative pole through a 10K resistor. When the resistance of the
LDR is about 5K, the voltage at the non-inverting pin is higher than the voltage at the inverting pin
so the voltage at the output is positive. When the resistance of the LDR is about 50K, the voltage at
non-inverting pin is lower than the voltage at inverting pin so the voltage at the output is zero. The
output pin is connected to the base of NPN transistor. If the voltage at the output is positive the
transistor will open and let the current run through the dc motor. If the output voltage is zero, the
transistor will be closed and the current cannot run though the motor. A sensor is a LED assembled
right next to a LDR. The robot has two sensors, one on the left and one on the right. To sum up, if
the light of the left sensor or the right sensor hits the black line, it won’t bounce up to the LDR so
the left motor or the right motor will be shut down by the comparator. Therefore, the robot will turn
left or right.
3
Figure 2 Control Circuit
4
5. Testing
After being completely assembled, the robot was tested for three times. All trials brought an
acceptable outcome which meant the function of the robot met all the requirements although its
speed was not as fast as our expectation.
6. Conclusion
In conclusion, the proposed Line Following Robot will autonomously start following a black line
when a barrier is opened. The robot also can turn left or turn right. Finally, when the robot
encounters the wall, it will raise a small flag.
Throughout the robot building process, our team learned many useful things in both social manner
and technical manner. The robot has some applications in real life, it can be used for goods
transport in warehouses or airports. Moreover, the line following robot can be used in car parks. To
be clearer, goods or cars can be carried on the robot, then it will be autonomously moved to an
appropriate place. Last but not least, with a DIY design and interesting movement, the line
following robot will be an amazing toy for children or anyone else who wants to learn about robot
from a very basic stage.
5
7. References
[1] Ban Biên Tập, "Công nghệ: Hướng dẫn làm một robot dò đường đơn giản," 1 November 2013.
[Online]. Available: http://evntel.com/news/cong-nghe/huong-dan-lam-mot-robot-do-duongdon-gian-133/. [Accessed 26 November 2013].
[2] Eric H. Glendinning; John McEwan, Oxford English for Electronics, Oxford University Press.
[3] Gordon McComb; Earl Boysen, Electronics For Dummies, Indianapolis: Wiley, 2005.
[4] P. Patil, "Line Following Robot," Mumbai.
[5] D. Cook, "Robot Building for Beginners," Apress, 2009.
6
Appendix A, Glossary of Terms
LED
LDR
Light emitting diodes
Light dependent resistor
A-1
Appendix B, List of Items and Estimated Costs
Items
Specification
White Plastic
Wheel
Diameter 20
mm
Operating
voltage 39VDC
male and
female head
Plastic
geared motor
Bus wire
Robot chassis
Test board
3.7V Lithium
Battery
Battery
holder
2.6 x 6.5 inch
Price per
unit ( VND )
Quantity
Total price
(VND)
Supplier
20,000
1
20,000
HSHOP
40,000
2
80,000
HSHOP
300
60
18,000
50,000
12,000
1
1
50,000
12,000
Mạch Tự Động
Shop
Nhật Tảo Market
Nhật Tảo Market
25,000
3
75,000
Nhật Tảo Market
5.000
3
15,000
Nhật Tảo Market
270.000
Total Cost (VND)
* Resistors, variable resistors, switches, Op amp, transistors, LEDs, LDR can be taken from VGU
Robotic LAB ( A001 )
Thiên Minh Electronic: http://www.tme.vn
HSHOP: http://www.hshop.vn
Mạch Tự Động Shop: http://www.machtudong.vn
Nhật Tảo Market address: 1st Floor, Nguyễn Kim Building, Nguyễn Kim Street, ward 7, district 10,
Hồ Chí Minh City, Việt Nam
B-1