25-01-2013, 02:28 PM
PLC Based Intelligent Traffic Control System
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ABSTRACT
The main object of this study was to design and implement
intelligent traffic control system. The system developed is able to
sense the presence or absence of vehicles within certain range by
setting the appropriate duration for the traffic signals to react
accordingly. By employing mathematical functions to calculate the
appropriate timing for the green signal to illuminate, the system can
help to solve the problem of traffic congestion. Hardware simulation
tests were successfully performed on the algorithm implemented into
a PLC (programmable logic controller).
INTRODUCTION
Traffic load is highly dependent on parameters such as time, day,
season, weather and unpredictable situations such as accidents, special
events or construction activities. If these parameters are not taken into
account, the traffic control system will create bottlenecks and delays. A
traffic control system that solves these problems by continuously
sensing and monitoring traffic conditions and adjusting the timing of
traffic lights according to the actual traffic load is called an intelligent
traffic control system.
Traffic control systems may also be classified as saturated or
unsaturated, depending on whether they were designed for a
saturated or unsaturated network. In an unsaturated network, it is
desired to minimize the mean delay of drivers, while in a saturated
network it is desired to serve as many drivers as possible, or in other
words, to maximize traffic capacity of the intersection. The problem
of capacity maximization is the same as the queue minimization
problem
OVERVIEWOF PLC BASED ITCS
The main theme of this report is to build and verify the designs and
understand the concept. The main objective is to build a hardware
device that has:
1. The ability to collect the information of the busy
tracks by sensors and providing the output to PLC.
2. The ability to take decision against the information
and change the time according to the priorities.
Traffic Control System
· Traffic signals control vehicle movements
· Traffic Control Systems are interconnected with
electronics system that controls traffic signals.
· Traffic Control Systems depend on logic which
can be divided into these categories:
i. The signal phases and cycle length
are depend on the traffic flow on the
desired track
ii. The system responds to interrupts or
timing base system and open the
desired signal according to the
priority requirement
What is Intelligent Traffic Control System (ITCS)?
An Intelligent Traffic Control System senses the presence
or absence of vehicles and reacts according to the sensors
output. In this system PLC takes a data from sensors and
checks the priorities. After that PLC provides signal to
traffic signals.
The intelligent traffic control system works in four
different modes are Normal flow, peak time, off time and
manual operation. Peak time and off time modes are
depended on the sensors outputs then change the status.
Our intelligent traffic control system totally depend on the
sensors output and take decisions.
Study overview
This study has two main parts. First is study of PLC and the second
part is its application intelligent traffic control system. The intelligent
traffic control system has further divided into two main parts,
Programming and hardware. Ladder logic Programming technique is
used. PLC T100MD2424+ is used for attaching with proto type
hardware. In hardware photoelectric sensors is used for sensing the
presence the vehicles on the square in proto type.
What is PLC?
A PLC (Programmable Logic Controller) is a device that was
invented to replace the necessary sequential relay circuits for
machine control. The PLC works by looking at its inputs and
depending upon their state, turning on/off its outputs. The user enters
a program, usually via software, that gives the desired results
Practical System Design
Practically Inductive Loops are used as sensors to detect the presence
of vehicles on intersections. Its basic function is to provide interrupts
to controller unit. It has two parts, first is coil and second is the
detector unit. Coil is a main part of a sensor and consists of one or
more loops of wire embedded in the pavement.
This inductive coil is connected with the detector unit, which is an
electronic circuit. When vehicles passes over or rests on the inductive
loop then due to induction on vehicle more current flow through
inductive loop and this change of current also changes frequency.
Detector unit can detect these changes. Finally, detector unit sends an
interrupt signal to controller unit.
CONCLUSION
An intelligent traffic light system had successfully been designed and
developed. The sensors were interfaced with Lab PLC Module. This
interface is synchronized with the whole process of the traffic system.
This prototype can easily be implemented in real life situations.
Increasing the number of sensors to detect the presence of vehicles
can further enhance the design of the traffic light system. Another
room of improvement is to have the infrared sensors replaced with an
imaging system/camera system so that it has a wide range of
detection capabilities, which can be enhanced and ventured into a
perfect traffic system.