Adaptive cruise control (ACC) provides assistance to the driver in the task of longitudinal control of their vehicle during motorway driving within limited acceleration ranges. The system controls the accelerator, engine powertrain and vehicle brakes to maintain a desired time-gap to the vehicle ahead.

1. ADAPTIVE CRUISE
CONTROL SYSTEM

2. CONTENTS
 Introduction
 Cruise Control
 Adaptive Cruise Control
 Principle
 Components
 Working
 Improvement
 Advantages
 Disadvantages
 Conclusion
 References

3. Introduction
 Increased accident rates
 On average at every minute one person dies in a crash
 Costs add up to 3% of world’s GDP
 The concept of assisting driver in the task of longitudinal
vehicle control is known as cruise control.
 First car - Chrysler Imperial in 1958
Source : Driver's behavioral adaptation to ACC : The case of speed and time headway

4. Cruise Control
 Cruise control - automatically controls the speed
of a motor vehicle.
 Also known as speed control or auto cruise.
 The conventional cruise control has one mode of
control, velocity control.
 Throttle position is adjusted to maintain a speed
set by the driver.
 Improves driver comfort in steady traffic
conditions.

5. Cruise Control
 The conventional cruise control is capable of only
maintaining a set speed by accelerating or
decelerating the vehicle.
 The driver always has to apply brake when
approaching the target vehicle proceeding at a
lower speed.
 In congested traffic conditions where speeds vary
widely these systems are no longer effective.

6. Adaptive Cruise Control
 ADAPTIVE CRUISE CONTROL is a common
term used for enhanced cruise control system.
 Collision-avoidance system
 Assists the driver to keep a safe distance from
the preceding vehicle by controlling the engine
throttle and brake.
 Free the driver from frequent accelerations and
decelerations and also reduces the stress of the
driver.

7. Adaptive Cruise Control
 Operates in two modes :
 Cruise mode : Speed of the vehicle is
controlled to maintain a set speed.
 Follow mode : Speed of the vehicle is
controlled to maintain a set distance from the
preceding vehicle.
 The driver can over-ride the system at any time.
 Effective in the speed between 30km/h-180km/h

8. Adaptive Cruise Control
 If 25% vehicles driving in a highway were equipped
with the ACC system, traffic congestions could be
avoided.
 In May 1998, Toyota became the first to introduce
an ACC system on a production vehicle, luxury
sedan.
Source : Development and testing of a fully Adaptive Cruise Control system

9. Working Principle
 Works by detecting the distance and speed of the
vehicles ahead by using either a LIDAR system or
a 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.

10. Doppler Effect
 Doppler Effect is the change in frequency of the
waves when there is a relative motion between
the transmitting and receiving units.
 The Doppler Effect can be categorize in two
ways:-

11. Higher Pitch Sound
 Vehicle speeding towards the stationary listener.
 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.
Source : Nassaree Benalie et al. (2009), Improvement of ACC System
based on Speed Characteristics and Time Headway.

12. Lower Pitch Sound
 Vehicle moving away from the listener.
 The distance between listener and the car is
increasing.
 The listener will hear a lower pitch sound from
the car, which means the frequency of sound, is
decreased.
Source : Nassaree Benalie et al. (2009), Improvement of ACC System
based on Speed Characteristics and Time Headway.

13. Working
 Switch on ACC.
 Set speed.
 Sensors detects vehicle ahead.
 Decelerate to ahead vehicle speed.
 Keeps safe distance
Source : Paul John King et al. (2000), Adaptive cruise control system

14. Source : Paul John King et al. (2000), Adaptive cruise control system
Source : Paul John King et al. (2000), Adaptive cruise control system

15. Block diagram showing configuration
of an ACC
Source : Tanimichi et al. Adaptive Cruise Control System

16. Components
 Sensors
 Longitudinal controller receives the sensor data
and process it to generate the commands to the
actuators using Control Area Network (CAN) of
the vehicle.
 Electronic vacuum actuator
Source : Gennaro Nicola Bifulco et al., Development and testing of a fully Adaptive
Cruise Control system

17. Sensors
 In this project three type of SENSOR can be used
 Kept behind the grill of the vehicle.
 Obtains velocity, distance, angular position and
lateral acceleration.

18. LIDAR
 LIDAR stands for “Light Detection and Ranging”.
 By measuring the beat frequency difference
between a Frequency Modulated Continuous light
Wave and its reflection.
Source : Greg Marsden et al. (2000), Towards an understanding of
adaptive cruise control

19. LIDAR
 It measures distance by illuminating laser and
analyzing the reflected light.
 Low cost
 Provides good angular resolution
 Weather conditions restrict its use to 30 - 40
meters range.

20. RADAR
 It operates by radiating energy into free space and
detecting echo signal reflected from an object.
 Currently used “Pulse Doppler RADAR” uses the
principle of Doppler effect.
 Current ACC systems are based on 77GHz
RADAR sensors.
 Detects moving object up to 120m.
 Work in poor weather conditions.

21. Block Diagram of Pulse Doppler Radar
Source : Greg Marsden et al. (2000), Towards an understanding of adaptive cruise
control

22. Fusion Sensor
 Millimeter wave RADAR linked to a stereo type
camera with a 40 degree view angle.
 These two parts track the car from non moving
object.
 It was first used by Fujitsu Ltd. and Honda.
Source : S. Paul Sathiyan et al. (April, 2013), A Comprehensive
review on Cruise Control for Intelligent Vehicles

23. Detection of Vehicle Edges by the
Fusion Sensor
Source : Seminar Topics.com/Adaptive Cruise Control System

24. Sensing and Controlling Process
Source : Greg Marsden et al. (2000), Towards an understanding of adaptive cruise control

25. Development of ACC
 Stop and Go Adaptive Cruise Control :
 Works primarily at lower speeds in heavy traffic.
 If the car in front stops, it will bring vehicle to a complete stop
 Co-operative Adaptive Cruise Control :
The preceding vehicles can communicate actively with the
following vehicles so that their speed can be coordinated with
each other.
Source : Gennaro Nicola Bifulco et al. (2011), Development and testing of a fully Adaptive
Cruise Control system

26. Advantages
 Driver is relieved from careful acceleration,
deceleration and braking in congested traffics.
 Accidents can be reduced.
 It’s very useful for long driving.
 Can avoid unconsciously violating speed limits.
 Increased fuel efficiency.
Source : Google.com/Images

27. Disadvantages
 High Cost.
 Not for heavy traffic.
 Encourages the driver to become careless.
 Dangerous in slippery roads.
 A high market penetration is required if a society of
intelligent vehicles is to be formed.
 The ACC systems not respond directly to the traffic
signals.
Source : S. Paul Sathiyan et al. (April, 2013), A Comprehensive review on Cruise Control
for Intelligent Vehicles.

28. Conclusion
 Current system ranges 150 meters can stop and
slows if any obstruction.
 Fully autonomous car is probably not viable in the
foreseen future.
 Near by vehicles would be in constant
communication with each other and act co-operatively.
 It will probably take decades, but car accidents may
eventually become rare.

29. References
1. S. Paul Sathiyan et al. (April, 2013), A Comprehensive review on
Cruise Control for Intelligent Vehicles. In: International Journal of
Innovative Technology and Exploring Engineering (IJITEE)
2. Gennaro Nicola Bifulco et al. (2011), Development and testing of a
fully Adaptive Cruise Control system
3. Nassaree Benalie et al. (2009), Improvement of Adaptive Cruise
Control System based on Speed Characteristics and Time
Headway. In: International Conference on Intelligent Robots and
Systems
4. Giulio Francesco Bianchi Piccinini et al. (2014), Driver's behavioral
adaptation to Adaptive Cruise Control (ACC): The case of speed
and time headway
5. Greg Marsden, Mike McDonald, Mark Brackstone (2000),
Towards an understanding of adaptive cruise control
6. Paul John King et al. (2000), Adaptive cruise control system
7. www.howstuffworks.com
8. www.youtube.com

30. Questions?

31. Thank You
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