ADAPTIVE CRUISE CONTROL
SUBMITTED TO:Mr. DURGESH KUMAR
Mr. PRAVEEN AGARWAL
SUBMITTED BY:VIPUL KUMAR JAIN (EC/10/128)
VIBHOR RATHI (EC/10/148)
SHWETA SHARMA (EC/10/99)
SHUBHAM CHOUDHARY (EC/10/97)
SHRAVAN CHOUDHARY (EC/10/96)
DEPARTMENT OF ELECTRONICS AND COMMUNICATION
POORNIMA COLLEGE OF ENGINEERING
ISI-2, RIICO INSTITUTIONAL AREA, JAIPUR
Working of Adaptive Cruise Control
The concept of assisting driver in longitudinal vehicle
control to avoid collisions is adaptive cruise control.
When switched on, this device takes up the task of
accelerating or braking to maintain a constant speed.
An “Adaptive Cruise Control” (ACC) system developed as
the next generation assisted the driver to keep a safe distance
from the vehicle in front.
ADAPTIVE CRUISE CONTROL is a common term used for
enhanced cruise control system.
Depending on car maker ACC can also be called as Active
Cruise Control (BMW), Distronic (MERCEDES), Dynamic
Cruise Control (TOYOTA).
ACC works by detecting the distance and speed of the
vehicles ahead by using radar system.
The time taken by the transmission and reception is the key
of the distance measurement.
The shift in frequency of the reflected beam by Doppler
Effect is measured to know the speed.
Depending on this speed, the brake and throttle controls are
done to keep the vehicle in a safe position with respect to the
Doppler Effect is the change in frequency of the waves when
there is a relative motion between the transmitting and
The Doppler Effect can be categorize in two ways:-
HIGHER PITCH SOUND
In this case the vehicle is speeding towards the stationary
The distance between the listener and the car is decreasing.
The listener will hear a higher pitch sound from the car,
which means the frequency of sound, is increased.
LOWER PITCH SOUND
In this case the vehicle is moving away from the listener.
The distance between and the car is increasing.
The listener will hear a lower pitch sound from the car, which
means the frequency of sound, is decreased.
So that is the Doppler Effect in case of sound waves.
WORKING OF ACC
The gun transmits the waves at a given frequency toward
an incoming car.
Reflecting waves return to the gun at a different
frequency, depending on how fast the car being tracked is
A device in the gun compares the transmission frequency
to the received frequency to determine the speed of the
We can design the chip or ACC having an algorithm such that
it will give output only when the input signals are less than
the corresponding safe distance value.
So only when the between the car and the object in front of it
is less then the same distance value the embedded system will
give output to the breaking and the accelerating units.
Thus the safe distance will be kept always.
auto braking signal
sense radar signal
BLOCK DIAGRAM WHEN VEHICLE IS STOPPED
sense radar signal
BLOCK DIAGRAM WHEN VEHICLE IS ACCELARATED
SENSOR is a converter that measure physical quantity and
converts it into signal which can be read by observer or by
SENSOR responds to an input quantity by generating a
functionally related output usually in form of electrical or
In this project three type of SENSOR can be used
It is an electromagnetic system for detection and location of
It operates by radiating energy into free space and detecting
echo signal reflected from an object.
The reflected energy is not only indicative of the presence but
on comparison with the transmitted signal , other information
of target can be obtained.
The currently used “Pulse Doppler RADAR” uses the
principle of Doppler effect in determining the velocity of
This include millimeter wave RADAR linked to a stereo type
camera with a 40 degree view angle.
These two parts work together to track the car from non
RADAR’s target is the car rear bumper, the stereo camera is
constantly captures all objects in its field of view.
It was first used by Fujitsu Ltd. and Honda.
LIDAR stands for “Light Detection and Ranging”.
It measure distance by illuminating laser and analyzing the
By measuring the beat frequency between frequency
modulated continuous light wave and its reflection.
It is of low cost and provide good resolution.
Weather condition restrict its use to 30 to 40 meter range.
The first ACC system used LIDAR sensor.
The AT89S51 is a low-power, high-performance CMOS
8-bit microcontroller with 4K bytes of in-system
programmable Flash memory.
The on-chip Flash allows the program memory to be
reprogrammed in-system or by a conventional nonvolatile memory programmer.
The AT89S51 provides the following standard features:
4K bytes of flash, 128 bytes of RAM, 32 I/O lines,
Watchdog timer, two data pointers, two 16-bit
timer/counters, a five vector two-level interrupt
architecture, a full duplex serial port, on-chip oscillator,
and clock circuitry.
Depending on present traffic situation two type of controller
are possible: SPEED CONTROL and HEADWAY
SPEED CONTROL: if there is no vehicle presently in front,
then the speed is controlled about a set point just as in
conventional cruise control.
HEADWAY CONTROL: in order to keep a safe distance
between the vehicle’s the headway control is required.
The driver is relieved from the task of careful acceleration,
deceleration and braking in congested traffic.
A high responsive traffic system that adjust itself to avoid
accident can be developed.
Since the braking and acceleration are done in systematic
way, the fuel efficiency of vehicle is increased.
Cost of ACC system is very high.
A high market penetration is required if a society of
intelligent vehicles is to be formed.
Encourages the driver to become careless, it can lead to
severe accident if the system is malfunctioning.
The advanced version of ACC is known as COOPERATIVE
ADAPTIVE CRUISE CONTROL (CACC).
In CACC preceding vehicle can communicate actively with
the following vehicle so that their speed can be coordinated
with each other.
It will probably take decades but car accident may eventually
become as rare as plane accidents are now.
Road laws have to be changed, up to an extent since the non
human part of the vehicle controlling will become