An Improved Algorithm for Collision Avoidance
System among Vehicles
Selvendran .S
Dr. S. Vasantharathna
Electrical and Electronics Department
Coimbatore Institute of Technology
Coimbatore, India
sselvendran6@gmail.com
Electrical and Electronics Department
Coimbatore Institute of Technology
Coimbatore, India
vasantharathna@cit.edu.in
Abstract— This paper proposes an Intelligent approach for
Collision Warning and Avoidance between vehicles in straight
roads and also at intersection roads using Vehicle to Vehicle
(V2V) communication and Vehicle to Infrastructure (V2I)
communication. It comprises of a wireless automotive
communication protocol where automobiles send messages to
each other with information about what they are doing. This
data would include speed, geographical location, direction of
travel, braking and loss of stability. In the intersection roads or
in the highways when the vehicles come to collide with each other
due to the improper functioning of drivers, by using V2V and
V2I communication, vehicles automatically gets the control from
the driver and acts to the emergency situation by applying the
brakes or changing the lane etc. This system considers safety and
better traffic management by using a Dedicated Short Range
Communication (DSRC) called ZigBee (802.15.4) as a wireless
protocol, Ultrasonic sensor, Compass sensor, Object sensor, and
RF Transceiver which are controlled by using ATmega162V
microcontroller. In this paper a prototype for Collision avoidance
system is shown by using a Robotic Cars with the sensors
implemented on it.
Keywords— V2V, V2I, ZigBee, Ultrasonic Sensor, Compass
Sensor, Object Sensor, Robotic Car.
I. INTRODUCTION
ccidents are the major cause for the loss of human lives,
which have a big number for human deaths from
vehicular accidents than deadly diseases or natural disasters.
About 70% of roadway collisions could be avoided if the
driver was provided with the warning of about one-half
second before the collision. According to the latest road
transport ministry report an Indian dies in a road accident for
every 3 minutes, since India is experiencing a car boom. India
is ranked second in the world for estimated road traffic deaths
per year, according to WHO’s global status report on road
safety published in 2013 [9]. From India’s premier automotive
magazine, there are currently around 1.6 to 1.7 million new
cars bought each year and these figures are expected to double
by the year 2015. But there are already large congestion
problems on Indian streets. The number of accidents continues
to rise, even though there is a technological innovations and
developments in the vehicle safety. This is especially true for
the accidents at the intersection roads. Accident rate is more at
the intersection roads than at the straight roads. Most of these
accidents take place at rural areas. Thus an intersection
A
collision warning system must be implemented as a part of
vehicle safety systems, inorder to reduce the large number of
road accidents. To be most effective, such a system should
have the capability of supporting real time systems that can
warn potential drivers of an impending collision. A study
conducted by the National Highway Traffic Safety
Administration (NHTSA) on intersection-related crashes in
2010 concluded that 44.1 percent of intersection-related
crashes were most directly attributed to inadequate driver
surveillance, compared to only 7.3 percent in non-intersectionrelated crashes.
In this paper, a safety system is proposed for the straight
roads and intersection roads, thus reducing the number of fatal
accidents at the roads by giving a proper warning to the driver
by displaying that there is an approaching vehicle with a
particular speed at particular distance. And if the driver
doesn’t notice and respond to the warning message then the
system automatically takes the control from the driver and acts
to emergency situation by applying brakes or changing lane
etc. A Vehicle to Vehicle communication and Vehicle to
Infrastructure communication technology is used for driver
assistance system and collision warning system. The
communication is mainly achieved by an automotive wireless
protocol which provides a 360 degree view of the vehicle
surroundings. The different participants for the automotive
wireless protocol are DSRC, ZigBee, WiFi, Bluetooth, UWB
[14]. From this, the best suitable protocol for this kind of
application is ZigBee (IEEE 802.15.4) which has a coverage
range of 10-100 meters with the less power consumption [11].
For collision avoidance, there were several options to choose
from in terms of selection of sensor. These includes infrared,
LIDAR [6], camera [5] and ultrasonic sensors [4]. Infrared
sensors, despite being cheap, were not a suitable choice as in
daytime outdoor operations, infrared radiation from the Sun
would have also interfered with sensors. LIDAR is an
accurate, reliable and effective collision avoidance and
obstacle detection system, however, it is an expensive,
unfeasible option compared to other solutions and thus was
not chosen. Camera for the front side was selected for
performing image processing because it is an accurate,
sophisticated method of determining obstacle position and
ensures that the vehicle moves in the correct direction to avoid
collision. Ultrasonic sensors have been widely used to detect
and avoid obstacles in mobile robot and automobile
applications [4]. Ultrasonic sensors were chosen and installed
on the front side of the vehicle because of their accuracy,
speed, reliability and effectiveness in detecting distance from
obstacles in addition to the fact that more cameras for these
sides would have resulted in slow, in effective and resourceintensive image processing. Object sensors are used at the rear
and right sides of the vehicle to detect the back approaching
vehicles and to see the overtaking vehicles. Compass sensor
is used to determine the heading and direction of travel of the
vehicle. Compass sensor is used instead of Global Positioning
System (GPS) [7]. GPS does not provide correct coordinates
value when the vehicle is moving in a tunnel due to the
blockage of satellite signal and also there is no change in
values for small movements.
The operation of all the sensors is controlled by the
ATmega162 Microcontroller. ZigBee is used which
broadcasts the values obtained from the onboard sensors.
Here an intelligent traffic management system is established
[16]. By using compass sensor in each vehicle, this intelligent
system calculates the number of vehicles present in each
direction and it is programmed such that, based on the density
of the vehicles the traffic light time interval varies for each
direction.
In [3], Suhas Chakravarty and Varun Jain proposed a low
cost driver assistance using a ZigBee protocol, describing the
usage of different ZigBee nodes placed at the sides of the roads
[2]. But this type of implementation is difficult in achieving
and cost effective. In [6], an optical vehicle-to-vehicle (V2V)
communication system based on an optical wireless
communication technology using an LED transmitter and a
camera receiver is proposed, which employs a special CMOS
image sensor, i.e., an optical communication image sensor
(OCI). This technology is helpful in identifying the obstacles in
straight to this vehicle but not efficient in intersection roads.
In this work, a simple prototype containing two Robotic
cars which performs communication between them and avoids
collision is demonstrated. This paper is organized as follows.
Section II describes the Vehicle to Vehicle safety application,
Section III explains the block diagram, Section IV explains the
hardware components used in this project, Section V describes
the mathematical modeling, Section VI explains the concepts
of Collision warning and Avoidance system, Section VII
explains Software Development, Section VIII shows the Result
and Discussion and Section IX concludes this paper.
II.
7.
If the vehicle suddenly breaks in the middle of the
road.
When the vehicle detects some risks, it issues the warning
message. Based on the Vehicle to Vehicle communication and
Vehicle to Infrastructure communication, the system provides
the following safety warnings.
1. Forward Collision Warning (FCW).
2. Rear Collision Warning (RCW).
3. Intersection Collision Avoidance (ICA).
4. Blind Spot and Lane Change Warning.
5. Do not pass warning.
6. Zone Warning.
Each Vehicle continuously broadcasts its speed, position, and
its driving direction.
III.
BLOCK DIAGRAM
The block diagram for the manual controlled vehicle is shown
in Fig.1 and for Autonomous vehicle is shown in Fig.2.
Various sensors are interfaced to microcontroller which
controls the motion of the car.
Fig. 1. Manual controlled Vehicle
VEHICLE-TO-VEHICLE SAFETY APPLICATION
From the Statistics of road accidents, the major reasons
for the road accidents are explained below [10].
1. If the front vehicle suddenly stops or slows down.
2. If the vehicle is in loss of control.
3. If the vehicle changes lanes suddenly.
4. If the vehicle drives across the roads junction where
is absent of traffic signal lights.
5. If the vehicle does not follow the traffic rules.
6. If the road is in congestion or abnormal.
Fig. 2. Autonomous Vehicle
IV.
HARDWARE
The following are the main components used to design the
prototype.
A. Robotic Car
The Robotic car consists of a chassis of 27 cm long and 1cm
ground clearance with steer mechanism for lateral control and
drive mechanism for longitudinal control, communication
modules for vehicle communication and control unit for
controlling the autonomous nature of the vehicle. A high
Torque Futaba S3010 Servomotor is used for steering, which
is controlled by the PWM signal and two DC motors with
appropriate gear reduction arrangement are used for
longitudinal drive mechanism. DC motor is driven by HBridge motor driver. The Robotic car is driven by
7.2V/2000mAh, Nickel Cadmium re-chargeable battery pack
[8].
sensor has a magnetic strip which aligns itself with magnetic
north, and from this, orientation can be determined. Thus,
because a compass sensor is used to determine just the
direction of a magnetic field, they are considered scalar
magnetometers. It has a features of I2C interface, 1-2 degree
heading accuracy, Integrated 12 bit ADC and 160 Hz max
data rate.
E. Object Sensor
Object sensor is a sensor able to detect the presence of nearby
objects without any physical contact. It often emits an
electromagnetic field or a beam of electromagnetic radiation
(infrared, for instance), and looks for changes in the field or
return signal. The object being sensed is often referred to as
the proximity sensor's target. Different object sensor targets
demand different sensors. For example, a capacitive or
photoelectric sensor might be suitable for a plastic target and
an inductive object sensor always requires a metal target.
F. ZigBee Module
Fig.3. Robotic Car
B. ATmega162 Microcontroller
ATmega162 is a High-performance, Low power AVR 8-bit
Microcontroller based on the advanced RISC Architecture. It
is a 40 pin PDIP with 35 programmable I/O lines operates
between 2.7 - 5.5V. It achieves a throughput of 16 MIPS at 16
MHz and has a high endurance Non-volatile memory
segments with 16KB of programmable Flash memory,
512Bytes EEPROM, 1KB internal SRAM and a JTAG
interface for on-chip debugging. Its peripheral features include
two 8-bit Timer/counters and two 16-bit Timer/counters, real
time counter with separate oscillator, six PWM channels, Dual
programmable serial USARTs and a programmable watchdog
timer.
C. Ultrasonic Sensor
HC-SR04 ultrasonic ranging modules are used to calculate
distance of obstacles from the vehicle. These sensors have a
maximum range of 500 cm and maximum effectual angle of
15⁰. It is also known as transceivers when they both send and
receive, but more generally called transducers, work on a
principle similar to radar or sonar, which evaluate attributes of
a target by interpreting the echoes from radio or sound waves
respectively. Active ultrasonic sensors generate high
frequency sound waves and evaluate the echo which is
received back by the sensor, measuring the time interval
between sending the signal and receiving the echo to
determine the distance to an object. Sensor is connected to
AVR and power supply via a 4 pin wire connector.
D. Compass Sensor
A compass sensor is a navigational instrument which is
sensitive to the magnetic field of the earth. A typical compass
IEEE 802.15.4/ZigBee is a standard protocol for Low-Rate
Wireless Personal Area Networks (LR-WPAN). Its main
features are network flexibility, low data rate, low cost and
very low power consumption, which make it suitable for an
adhoc network between inexpensive fixed, portable and
moving devices. The IEEE 802.15.4 protocol includes a PHY
layer and MAC sub-layer for the LR-WPAN. The PHY layer
offers three operational frequency bands; there are 27 channels
allocated in the 802.15.4 range, with 16 channels in the 2.4
GHz band, 10 channels in the 915 MHz band, and 1 channel in
868 MHz band [11], [13].
Parameters
ZigBee Value
Transmission Range(Meters)
1 - 100
Battery life (days)
100 – 1000
Network size(# of nodes)
> 64,000
Throughput (kb/s)
20 - 250
Fig.4. ZigBee Specification
G. RF Module
A RF module (radio frequency module) is a small electronic
device used to transmit and/or receive radio signals between
two devices. In an embedded system it is often desirable to
communicate with another device wirelessly. This wireless
communication may be accomplished through optical
communication or through Radio Frequency (RF)
communication. For many applications the medium of choice
is RF since it does not require line of sight. RF
communications incorporate a transmitter and/or receiver. It
can send only 0 and 1 value.
H. Liquid- Crystal Display
It is a flat panel display, electronic visual display, or video
display that uses the light modulating properties of liquid
crystals. A 20x4 LCDs are used to display the information
which is interfaced to AVR microcontroller.
V. MATHEMATICAL MODELLING
From Equation (1), 𝑉 = 𝑟𝜔, rewriting the equation,
The steering of the vehicle is controlled by the high precision
servo motor. By basic physics, the relation between the linear
and angular velocity is given as,
𝑣 = 𝑟𝜔
(1)
where ‘v’ is the linear velocity of the vehicle, ‘r’ is the radius
and ‘ω’ is the angular velocity.
From the values of the current velocity and the angular
position of the vehicle, the position of the vehicle at any point
can be accurately given by the fundamental relationship
between the parameters. The relation between the linear and
the angular velocity is shown in Fig.9. The horizontal and
vertical components of the velocity can be decomposed as
shown in Fig.10.
Fig. 5. Angular velocity and Linear velocity
Fig. 6. Velocity components
The horizontal and vertical component of velocity is related to
their corresponding displacements as given in equations (2)
and (3).
𝑑𝑥
𝑣𝑥 =
(2)
𝑑𝑡
𝑣𝑦 =
𝑑𝑦
𝑑𝑡
(3)
𝑡
𝑡
𝑥 = ∫0 𝑣(𝑡) cos 𝜃(𝑡) 𝑑𝑡
(4)
(5)
Similarly for y co-ordinate,
𝑡
𝑦 = ∫0 𝑣(𝑡) sin θ(𝑡) 𝑑𝑡
(6)
In differential form, it can be given in equations (7) and (8).
𝑥̇ = cos 𝜃 (𝑡). 𝑣(𝑡)
(7)
𝑦̇ = sin 𝜃 (𝑡). 𝑣(𝑡)
(8)
(9)
The vehicle model can be thus given as,
𝑥̇
cos 𝜃
cos 𝜃
0
[𝑦̇ ] = [ sin 𝜃 ] [𝑣] = [ sin 𝜃 ] 𝑣 + [0] 𝜔
1⁄𝑟
0
1
𝜃̇
(10)
where 𝑥̇ denotes the linear velocity in x direction which
depends on cosine function, 𝑦̇ represents linear velocity in y
direction which corresponds to sin function and 𝜃̇ corresponds
to angular velocity.
VI.
COLLISION WARNING AND AVOIDANCE
SYSTEM
A. Description of Concepts
This section describes the detailed working of this project,
explains about the working of Vehicle to Vehicle
communication and Vehicle to Infrastructure communication
between Vehicles.
Here a Collision Avoidance System is implemented for two
cases, one for Straight roads and another for Intersection roads.
Two Robotic cars are used for prototyping, each vehicle is
equipped with the ATmega162V microcontroller, and
interfaced with the different sensors for obstacle detectance,
and direction of travel etc.
ZigBee is used as an automotive wireless protocol used to
broadcast the information continuously from each vehicle. The
information includes the speed of the vehicle, heading and
distance between the nearby vehicle. At Intersection there are
different points which are conflict to collision [1].
Consider the collision avoidance in straight roads, ultrasonic
sensor is placed infront of the vehicle, which is controlled by
the microcontroller, continuously emits the ultrasonic waves,
the waves after striking any obstacle bounces back and reach
the receiver. By measuring the time it take for the whole
process to complete and by using simple arithematic, can
measure distance to the obstacle.
To calculate distance (cm) =
Where ‘x’ and ‘y’ are the displacement in horizontal and
vertical direction respectively. The position of the vehicle is
given in equations (4), (5) and (6).
𝑥 = ∫0 𝑣𝑥 (𝑡)𝑑𝑡
1
1
𝜔 = 𝑣 and 𝜃̇ = 𝜔(𝑡) = 𝑣(𝑡)
𝑟
𝑟
𝑃𝑢𝑙𝑠𝑒 𝑤𝑖𝑑𝑡ℎ
58
The vehicle 1 continuously scans the presence of any vehicle
within the coverage area of the current vehicle. If it detects the
presence of any vehicle then by receiving the information
broadcast by that vehicle, and obtained the direction of travel.
If that value is same to that of the vehicle 1, then that both
vehicles are in the same road ie, Straight road, and if that
values are different, then the vehicles are at intersection roads.
Warnings are provided to the driver inorder to avoid the
collision and if the driver doesn’t respond to the situation then
the vehicle automatically takes the control from the driver and
acts to the emergency situation by applying brakes.
B. In Straight Roads
The Flow chart for the collision avoidance system at straight
roads is shown in Fig. 7. In that each vehicle is implemented
with the ultrasonic sensor at the front. Vehicles broadcast their
speed and direction of travel through ZigBee. By using
compass sensor values the system checks whether the vehicle
near to it is in the same heading or at intersection. Ultrasonic
sensor continuously checks the presence of any obstacle or any
vehicle moving infront. The system warns the driver regarding
collision ahead if the distance measured by the ultrasonic
sensor decreases and if the driver neglects to reduce the speed
then the system immediately reduces the speed and applies the
brake automatically when the distance decreases below the
threshold value. Through this system the V2V features like
Forward Collision Warning, Rear Collision Warning, Blind
spot and Lane change Warning is achieved.
DUDE or USBasp. Fig. 8 shows the steps for software
development.
Fig. 8. Steps for software development
The snapshot of C coding for the proposed system using AVR
Studio6 is shown in Fig. 9.
Fig. 9. Coding in AVR Studio6
VIII. RESULTS AND DISCUSSION
Fig. 7. Flowchart
VII. SOFTWARE DEVELOPMENT
ATmega162V microcontroller is used to control the proposed
system. Software development gives the pep and functionality
to the system. The coding for this system is written in
embedded C language and AVR studio6 is used as compiler.
AVR functions like UART, timer, ADC, interrupts, etc are
handled by AVR studio6 and provide the facility to write the
program in embedded ‘C’. The resultant of the program is
obtained in hex code file which burn into flash memory of
AVR microcontroller using a AVR programmer called AVR
The results for this proposed system is shown through the
Hardware Implementation. Two Robotic cars are made to run
in the small track. The first vehicle (Robotic car 1) is
autonomous and the second vehicle (Robotic car 2) is of
manual type. Consider the two cars going in a straight road one
after the another and if the first car slows down the speed then
the ultrasonic sensor placed in the second car will continuously
measure the distance from the forward car. If that distance
reduces below 80 cm then the system will warn the driver
regarding collision ahead. If the first car suddenly stops, then
the second car provides warning to the driver and at the same
time reduces the speed by decreasing the PWM values given to
the motor. If the distance decreases below the threshold value
of 10 cm, then the system completely stops the second car
which is conflict to collision. The result is shown in the Fig.
10.
Fig. 10. Prototype
Distance
(cm)
33
50
72
103
Ton
(ms)
Toff
(ms)
Duty Cycle
(%)
0.6
2.4
1.2
1.8
1.5
1.5
1.8
1.2
Fig. 11. Obtained Value
Distance = 33cm
20
40
50
60
Distance = 50cm
Distance = 72cm
Distance = 103cm
Fig. 12. Waveforms
The duty cycle for different values of distance measured by
ultrasonic sensor was tabulated and is shown in Fig. 11. The
Fig. 12 shows the waveforms of PWM obtained from CRO for
different distance values. These PWM values are given to the
DC motors for controlling the speed when the obstacle
approaches infront of the vehicle.
IX. CONCLUSION
A Low-cost and an Improved approach for Collision Warning
and Avoidance system is proposed. Through this project, a
miniature Robotic car was developed which is capable of
performing the basic tasks a normal vehicle has to do. In this
project, we have detected the obstacles with the help of
Ultrasonic sensors, then the collision warning is given to the
driver and also automatic collision avoidance is achieved
successfully using Vehicle to Vehicle communication.
Although this project is done using a simple prototype, it can
be implemented on actual cars also, as the basic concepts
remain the same. If the ultrasonic sensors or Object sensors are
placed in the sides and rear of the vehicle, then the driver can
get the 360 degree view of their vehicle. This system will be
helpful in minimizing the accidents.
In future work, Collision warning and Avoidance system can
be done for Intersection roads and these concepts can be
established and tested in real time vehicles inorder to determine
the efficiency of the system in real time world.
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