Adaptive cruise control

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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.

Transcript of Adaptive cruise control

  • 1. ADAPTIVE CRUISECONTROL 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 worlds GDP The concept of assisting driver in the task of longitudinalvehicle control is known as cruise control. First car - Chrysler Imperial in 1958Source : Driver's behavioral adaptation to ACC : The case of speed and time headway 4. Cruise Control Cruise control - automatically controls the speedof a motor vehicle. Also known as speed control or auto cruise. The conventional cruise control has one mode ofcontrol, velocity control. Throttle position is adjusted to maintain a speedset by the driver. Improves driver comfort in steady trafficconditions. 5. Cruise Control The conventional cruise control is capable of onlymaintaining a set speed by accelerating ordecelerating the vehicle. The driver always has to apply brake whenapproaching the target vehicle proceeding at alower speed. In congested traffic conditions where speeds varywidely these systems are no longer effective. 6. Adaptive Cruise Control ADAPTIVE CRUISE CONTROL is a commonterm used for enhanced cruise control system. Collision-avoidance system Assists the driver to keep a safe distance fromthe preceding vehicle by controlling the enginethrottle and brake. Free the driver from frequent accelerations anddecelerations and also reduces the stress of thedriver. 7. Adaptive Cruise Control Operates in two modes : Cruise mode : Speed of the vehicle iscontrolled to maintain a set speed. Follow mode : Speed of the vehicle iscontrolled to maintain a set distance from thepreceding 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 equippedwith the ACC system, traffic congestions could beavoided. In May 1998, Toyota became the first to introducean ACC system on a production vehicle, luxurysedan.Source : Development and testing of a fully Adaptive Cruise Control system 9. Working Principle Works by detecting the distance and speed of thevehicles ahead by using either a LIDAR system ora RADAR system. The time taken by the transmission and receptionis the key of the distance measurement. The shift in frequency of the reflected beam byDoppler Effect is measured to know the speed. Depending on this speed, the brake and throttlecontrols are done to keep the vehicle in a safeposition. 10. Doppler Effect Doppler Effect is the change in frequency of thewaves when there is a relative motion betweenthe transmitting and receiving units. The Doppler Effect can be categorize in twoways:- 11. Higher Pitch Sound Vehicle speeding towards the stationary listener. The distance between the listener and the car isdecreasing. The listener will hear a higher pitch sound fromthe car, which means the frequency of sound, isincreased.Source : Nassaree Benalie et al. (2009), Improvement of ACC Systembased on Speed Characteristics and Time Headway. 12. Lower Pitch Sound Vehicle moving away from the listener. The distance between listener and the car isincreasing. The listener will hear a lower pitch sound fromthe car, which means the frequency of sound, isdecreased.Source : Nassaree Benalie et al. (2009), Improvement of ACC Systembased on Speed Characteristics and Time Headway. 13. Working Switch on ACC. Set speed. Sensors detects vehicle ahead. Decelerate to ahead vehicle speed. Keeps safe distanceSource : Paul John King et al. (2000), Adaptive cruise control system 14. Source : Paul John King et al. (2000), Adaptive cruise control systemSource : Paul John King et al. (2000), Adaptive cruise control system 15. Block diagram showing configurationof an ACCSource : Tanimichi et al. Adaptive Cruise Control System 16. Components Sensors Longitudinal controller receives the sensor dataand process it to generate the commands to theactuators using Control Area Network (CAN) ofthe vehicle. Electronic vacuum actuatorSource : Gennaro Nicola Bifulco et al., Development and testing of a fully AdaptiveCruise 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 andlateral acceleration. 18. LIDAR LIDAR stands for Light Detection and Ranging. By measuring the beat frequency differencebetween a Frequency Modulated Continuous lightWave and its reflection.Source : Greg Marsden et al. (2000), Towards an understanding ofadaptive cruise control 19. LIDAR It measures distance by illuminating laser andanalyzing the reflected light. Low cost Provides good angular resolution Weather conditions restrict its use to 30 - 40meters range. 20. RADAR It operates by radiating energy into free space anddetecting echo signal reflected from an object. Currently used Pulse Doppler RADAR uses theprinciple of Doppler effect. Current ACC systems are based on 77GHzRADAR sensors. Detects moving object up to 120m. Work in poor weather conditions. 21. Block Diagram of Pulse Doppler RadarSource : Greg Marsden et al. (2000), Towards an understanding of adaptive cruisecontrol 22. Fusion Sensor Millimeter wave RADAR linked to a stereo typecamera with a 40 degree view angle. These two parts track the car from non movingobject. It was first used by Fujitsu Ltd. and Honda.Source : S. Paul Sathiyan et al. (April, 2013), A Comprehensivereview on Cruise Control for Intelligent Vehicles 23. Detection of Vehicle Edges by theFusion SensorSource : Seminar Topics.com/Adaptive Cruise Control System 24. Sensing and Controlling ProcessSource : 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 thefollowing vehicles so that their speed can be coordinated witheach other.Source : Gennaro Nicola Bifulco et al. (2011), Development and testing of a fully AdaptiveCruise Control system 26. Advantages Driver is relieved from careful acceleration,deceleration and braking in congested traffics. Accidents can be reduced. Its 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 ofintelligent vehicles is to be formed. The ACC systems not respond directly to the trafficsignals.Source : S. Paul Sathiyan et al. (April, 2013), A Comprehensive review on Cruise Controlfor Intelligent Vehicles. 28. Conclusion Current system ranges 150 meters can stop andslows if any obstruction. Fully autonomous car is probably not viable in theforeseen future. Near by vehicles would be in constantcommunication with each other and act co-operatively. It will probably take decades, but car accidents mayeventually become rare. 29. References1. S. Paul Sathiyan et al. (April, 2013), A Comprehensive review onCruise Control for Intelligent Vehicles. In: International Journal ofInnovative Technology and Exploring Engineering (IJITEE)2. Gennaro Nicola Bifulco et al. (2011), Development and testing of afully Adaptive Cruise Control system3. Nassaree Benalie et al. (2009), Improvement of Adaptive CruiseControl System based on Speed Characteristics and TimeHeadway. In: International Conference on Intelligent Robots andSystems4. Giulio Francesco Bianchi Piccinini et al. (2014), Driver's behavioraladaptation to Adaptive Cruise Control (ACC): The case of speedand time headway5. Greg Marsden, Mike McDonald, Mark Brackstone (2000),Towards an understanding of adaptive cruise control6. Paul John King et al. (2000), Adaptive cruise control system7. www.howstuffworks.com8. www.youtube.com 30. Questions? 31. Thank You