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ADAPTIVE CRUISE CONTROL
INTRODUCTION
Every day the media brings us the horrible news on road accidents. Once a report said that the damaged property and other costs may equal 3 % of the world’s gross domestic product. The concept of assisting driver in longitudinal vehicle control to avoid collisions has been a major focal point of research at many automobile companies and research organizations. The idea of driver assistance was started with the ‘cruise control devices’ first appeared in 1970’s in USA. When switched on controls the vehicle speed by adjusting throttle position of engine to maintain a speed set by the driver. A control unit compares the actual vehicle speed and desired set speed. If there is a difference between these two values, a signal is sent to the throttle position actuator to adjust the throttle position to bring the vehicle’s speed to the set speed. But it could not consider the other vehicles on the road.
An ‘Adaptive Cruise Control’ (ACC) system developed as the next generation assisted the driver to keep a safe distance from the vehicle in front. ACC is an automotive feature that allows a vehicle's cruise control system to adapt the vehicle's speed to the traffic environment. A radar system attached to the front of the vehicle is used to detect whether slower moving vehicles are in the ACC vehicle's path. If a slower moving vehicle is detected, the ACC system will slow down the vehicle and control the clearance, or time gap, between the ACC vehicle and the forward vehicle. If the system detects that the forward vehicle is no longer in the ACC vehicle's path, the ACC system will accelerate the vehicle back to its set cruise control speed. This operation allows the ACC vehicle to autonomously slow down and speed up with traffic without intervention from the driver. The method by which the ACC vehicle's speed is controlled is via engine throttle control and limited brake operation. This system is now available only in some luxury cars like Mercedes S- class, Jaguar, Volva trucks etc. The U.S. Department of transportation and Japan’s ACAHSR have started developing ‘Intelligent Vehicles’ that can communicate with each other with the help of a system called ‘Cooperative Adaptive Cruise control”.
An ‘Adaptive Cruise Control’ (ACC) system developed as the next generation assisted the driver to keep a safe distance from the vehicle in front. ACC is an automotive feature that allows a vehicle's cruise control system to adapt the vehicle's speed to the traffic environment. A radar system attached to the front of the vehicle is used to detect whether slower moving vehicles are in the ACC vehicle's path. If a slower moving vehicle is detected, the ACC system will slow down the vehicle and control the clearance, or time gap, between the ACC vehicle and the forward vehicle. If the system detects that the forward vehicle is no longer in the ACC vehicle's path, the ACC system will accelerate the vehicle back to its set cruise control speed. This operation allows the ACC vehicle to autonomously slow down and speed up with traffic without intervention from the driver. The method by which the ACC vehicle's speed is controlled is via engine throttle control and limited brake operation. This system is now available only in some luxury cars like Mercedes S- class, Jaguar, Volva trucks etc. The U.S. Department of transportation and Japan’s ACAHSR have started developing ‘Intelligent Vehicles’ that can communicate with each other with the help of a system called ‘Cooperative Adaptive Cruise control”.
