Automated Guided Vehicle

The Design and Implementation of Automated
Guided vehicle
Mr. Manish Dubey, Abhishek Saxena and Swetank Mishra
Electrical and Electronics department
S.R.M.S.C.E.T, Bareilly, India
[email protected], [email protected]

Abstract—In order to make the optimum utilization of the
human resource (the most important resource) in an
organization, the humans must be replaced by the autonomous
machines that are capable of taking the decisions as per the need
or as programmed. These intelligent machines are called as the
‘Automated Guided Vehicles’ (AGV) or ‘Automatic
Transportation System’. Such machines prove to be an effective
method to increase the efficiency rate, along with the removal of
the chances of error. This paper presents various aspects while
designing an autonomous machine right from the nutshell,
including the hardware and software specifications. The
vehicular automation involves the use of mechatronics, artificial
intelligence for the operation. The system uses infrared (IR)
sensors to follow a floor-painted track to enable the vehicle to
reach the destination. Also, it includes the designing of a remote
control vehicle having the facility of tracking the position of the
vehicle It will further focus upon the various challenges subjected
to them and the future scope.
Index
Terms—Autonomous,
Transportation
Mechatronics, Artificial Intelligence

System,

I. INTRODUCTION
Automated guided vehicles (AGVs) are known to increase
the efficiency of production and reduce costs in a
manufacturing process. The first AGV was developed by
Barett Electronics in 1953. It can tow objects behind them in
trailers to which they can autonomously attach. These trailers
can be used to move raw materials or finished goods. The
AGV can also store objects on a bed. The objects can be placed
on a set of motorized rollers (conveyor) and then pushed off by
reversing them. AGVs are almost used in every industry. An
Automated Guided Vehicle (AGV) is a set of cooperative
driverless vehicle, used on manufacturing floor and
coordinated by a centralized or distributed computer-based
control system. Moreover there is a growing scientific interest
on the development of small, cheap and modular systems
endowed with distributed control systems based on low
consumption and easy to modify electronics.

This paper will present a low-cost prototype of an AGV
intended for research and development.
II. MOTIVATION AND PROBLEM DEFINITION
Automation has become the core of modern
manufacturing so much so that, no company is able to survive
in a competitive market without automating its operations.
Nowadays, manufacturers seek to implement methods of
automation appropriate to their needs and purposes. Companies
automate their activities for a variety of reasons. Increasing
productivity is normally the main aim for companies desiring
competitive advantages. Automation reduces human errors and
improves the quality of output. . Automation is used to manage
systems and to control processes, thus leading to reduce the
necessity of human intervention. The main focus of this study
is to make an AGV with the convenient materials, simple and
applicable routing system and more importantly reducing the
cost and increasing the flexibility. Automated guided vehicles
(AGVs) are now becoming popular in automated materials
handling systems, flexible manufacturing systems and even
container handling applications. The AGV must follow a 5cm
wide track painted on a flat floor. There is no specific color for
the track, as the color and reflection parameters of the track
detector are adjustable. The only requirement is a good contrast
between track and background floor. The AGV must also
detect a track interruption and detect where the track resumes
after the interruption, by using a passive beacon searching
sensor (track finder) mounted on the top of the AGV. The
track is composed of segments of two types: lines and arcs. The
minimum radius of the arcs should be of approximately 1m in
length.
III. BLOCK DIAGRAM AND WORKING PRINCIPLE
The block diagram of working of an Infrared sensor based
AGV is shown below, it’s all three basic building blocks are
given below

1.
2.
3.
4.

5.

1.

Controlling Unit, it includes the microcontroller that
is Atmega8 in our prototype.
Sensing Unit, it includes a pair of IR-based sensors
that works on the principle of reflection of light.
Actuating Unit, it includes a pair of external geared
DC motors that causes the motion of the vehicle.
Power Unit, it includes a NiCd battery (7.2 V-1.8 A/h)
was used to drive two DC motors and provides the
regulated power supply to the controlling unit.
Position Detection Unit, it includes a GPS module for
the determination of the exact position of the vehicle.

Controlling Unit

As the name indicates this unit has the overall command of all
blocks or this unit decides when to use & which unit has to be
used. Since it is a programmable device it provides the facility
to update the device without changes in hardware & it also
reduces the hardware required to implement the circuit. The
controlling unit comprises of an Atmega16 microcontroller,
which is a 40-pin IC and belongs to the ATMEL Mega
category of AVR family. It is the central unit, which
comprises of a program inserted by the user in the form of a
hex code. This program is responsible for providing a specific
output under the influence of a specific input or operating
conditions.
2.

Sensing Unit

Inductive following, where two analog sensors control the
vehicle direction, is the most usual AGV guidance technique. It
contains an IR transmitter & an IR receptor. IR LED can act as
IR transmitter while a photodiode/phototransistor can act as IR
receptor. The IR transmitter transmits the IR rays which are
reflected by the object/obstacle, and received by the IR
receptor. The amount of current output from the IR receptor
depends upon the intensity of light falling on the IR receptor.
Greater the amount of light falling on the IR receptor, greater is
the output current and vice-versa. The variation in current is
reflected in the variation in voltage, which is used to detect the
distance of the object/obstacle from the sensor. So, when the
infrared rays falls on the black surface, no light will be
reflected, since black color absorbs the radiations, but when it
will fall on the white color surface, all the light will be
reflected back, because white reflects all the radiations. The
schematics is shown,

3.

There are two 12V-3A external geared DC electro motors
adjusted and tighten to the motor plates on each side. We have
used the geared motors because in comparison to normal
motors, they have more torque, since:
Torque = Force * Perpendicular distance

Actuating Unit

Power Transfer System: (two sets, one for each side)
1) Driver Gear: A spur gear is fixed to the motor output
axis. This gear is not only meant to transfer the power
from the motor shaft to the driven gears, but also to keep
the belt over the gear set in order to have continuous
revolution under the load. This is done by special two
fixture rings wielded to each side of this gear called gear
guards.
2) Fixed Shafts: At the bottom of the AGV there are two
shafts parallel to the chassis with each 175 millimeter
away from the center welded to the base. In order to be
able to assemble the pinion gears on these shafts, the
diameter is reduced using turning machining by 10
millimeter from each head for 25millimeter.
3) Pinion Gears: There is a pair of spur gears on each side
seated on the fixed shaft with ball bearings.
Consequently, these gears have only one rotational
degree of freedom around the shaft.
4) Belts: 120 teeth timing belt is meant to transfer power.
4.

Position Detection Unit using GPS

Global Positioning System satellites transmit signals to
equipment on the ground. GPS receivers passively receive
satellite signals; they do not transmit. GPS receivers require an
unobstructed view of the sky, so they are used only outdoors
and they often do not perform well within forested areas or
near tall buildings. GPS operations depend on a very accurate
time reference, which is provided by atomic clocks at the U.S.
Naval Observatory. Each GPS satellite has atomic clocks on
board. A GPS receiver "knows" the location of the satellites,
because that information is included in satellite transmissions.
By estimating how far away a satellite is, the receiver also
"knows" it is located somewhere on the surface of an
imaginary sphere centered at the satellite. It then determines
the sizes of several spheres, one for each satellite. The receiver
is located where these spheres intersect. There are at least 24
operational GPS satellites at all times plus a number of spares.
The satellites, operated by the US DoD, orbit with a period of
12 hours (two orbits per day) at a height of about 11,500 miles
traveling at near 2,000mph. Ground stations are used to
precisely track each satellite's orbit. All GPS satellites have

several atomic clocks. The signal that is sent out is a random
sequence, each part of which is different from every other,
called pseudo-random code. This random sequence is repeated
continuously. All GPS receivers know this sequence and repeat
it internally. Therefore, satellites and the receivers must be in
synch. The receiver picks up the satellite's transmission and
compares the incoming signal to its own internal signal. By
comparing how much the satellite signal is lagging, the travel
time becomes known.

This table shows the complete four combinations, when we
use two IR sensors, now the basic algorithm is presented
below, describing the working of the AGV,

.
The schematic diagram of the transmitter and receiver of a GPS
module is shown below,

IV.
WORKING ALGORITHM
In our prototype of the AGV, we have used a pair of
sensors, placed at the bottom, sensing the black and white track
on the floor, named as left and right sensor.
Therefore the number of conditions = 4
TABLE I
COMBINATION OF 2 IR SENSORS
IR1
0
1
0
1

IR2
0
0
1
1

V.
REQUIRED NUMBER OF AGVS
There is a mathematical analysis, which can be used to extract
the number of AGVs to be employed in an organization to
perform the tasks, which becomes a mandatory study.
The following notations are used:
D1 = Average travel distance (Loaded) dd
D2 = Average Travel distance (Empty) dc
N1 = Number of deliveries required per hour. ndr
T.F = Traffic factor that accounts for blocking of vehicles
and waiting of vehicles in line and at intersection.
Under no congestion stage, the traffic factor is 1. However,
when more vehicles are involved, the traffic factor value will
certainly be less than 1. Normally, T.F lies between 0.85 and 1.
v = Vehicle speed.
T3 = Loading and unloading time.
The total time per delivery per vehicle (T4) is given by the
sum of loaded travel time, empty travel time, loading and
unloading time, as follows:
T4= D1 / v + T3 + D2 / v
Number of deliveries per vehicle per hour
N2 = 60 T.F / T4
Number of automated guided vehicles = N1 / N2
Thus, we can get an approximate value of the vehicles needed
in an organization with the given constraints.
VI.

CHALLENGES FACED BY AGVS

An industrial traffic management and control system based
on Automated Guided Vehicles faces several combined
problems. Decisions must be made concerning which vehicles
will respond, or are allocated to each of the transport orders.
Once a vehicle is allocated a transport order, a route has to be

selected that allows it to reach its target location. In order for
the vehicle to move efficiently along the selected route it must
be provided with the means to recognize and adapt to the
changing characteristics of the path it must follow. When
several vehicles are involved, these decisions are interrelated
and must take into account the coordination of the movements
of the vehicles in order to avoid collisions and maximize the
performance of the transport system. This research
concentrates on the problem of routing the vehicles that have
already been assigned destinations associated with transport
orders. In nearly all existing AGV systems this problem is
simplified by considering there to be a fixed route between
source and destination workstations. However if the system is
to be used more efficiently, and particularly if it must support
the requirements of modern manufacturing strategies, such as
Justin- Time and Flexible Manufacturing Systems, of moving
very small batches more frequently, then there is a need for a
system capable of dealing with the increased complexity of the
routing problem. The consideration of alternative paths
between any two workstations together with the possibility of
other vehicles blocking routes while waiting at a particular
location, increases enormously the number of alternatives that
must be considered in order to identify the routes for each
vehicle leading to an optimum solution. Current methods used
to solve this type of problem do not provide satisfactory
solutions for all cases, which leaves scope for improvement.
The approach proposed in this work takes advantage of the use
of Back propagation Artificial Neural Networks to develop a
solution for the routing problem. A novel aspect of the
approach implemented is the use of a solution derived for
routing a single vehicle in a physical layout when some pieces
of track are set as unavailable, as the basis for the solution
when several vehicles are involved. Another original aspect is
the method developed to deal with the problem of selecting a
route between two locations based on an analysis of the
conditions of the traffic system, when each movement decision
has to be made. To test and implement these phases a specific
layout was selected and an algorithm was implemented to
generate the data required for the design of the ANN solution.
During the development of alternative solutions it was found
that the addition of simple rules provided a useful means to
overcome some of the limitations of the ANN solution, and a
"hybrid" solution was originated. Numerous computer
simulations were performed to test the solutions developed
against alternatives based on the best published heuristic rules.
The results showed that while it was not possible to generate a
globally optimal solution, near optimal solutions could be
obtained and the best hybrid solution was marginally better
than the best of the currently available heuristic rules.
VII.

CONCLUSION

An Automated guided vehicle (AGV) is defined as a set of
cooperative driverless vehicle, which is used on manufacturing
floor and coordinated by a centralized or distributed computerbased control system. The main usage of them as mentioned is
to facilitate automation process of doing manufacturing
subjects. In this practical research, according to the instructions
of earlier study, an AGV have been made using an innovation

of artificial landmark has been discussed and tested. It is
called IR coding. This artificial landmark is designed for line
follower robot to enhance the localization feature so it will
have the ability to localize itself. The IR coding has been
tested to be used in the intersection. The line follower robot
has the ability to identify each intersection and perform the
action accordingly. This innovation has many advantages like
flexibility, reliability and it is inexpensive.
VIII.

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