Saturday, August 30, 2008

The Automobile Cruise Control

The automobile cruise control, or the ACC for short, is guided by microwave radar and controlled by a microcontroller cruise control and can be found in all kinds of automobiles on the roads today, including the heavier type vehicles.This type of unit can help a driver maneuver through busy streets and can do the job of alerting the driver about the cars or obstacles ahead within a range of up to 75 meters. In multilane highways, an option is available which displays, with the help of a camera, the cars behind while you may be in the process of changing lanes.The ACC acts as an amiable assistance or a co-pilot to the driver and unlike the orthodox cruise control systems which use electronic throttle to maintain speed and prompt the electromechanical braking when in an emergency; the ACC does not intervene in the vehicle's dynamics.
This is because all cars have separate ACC's which are customized to do jobs according to the vehicle's build.For example the Cadillac XLR comes fitted with an automatic cruise control enhanced with radar capabilities. The Audi A8 has similar features. Cars ranging anywhere from $70,000 - $80,000 can be found enhanced with these radar capabilities. Radar kits can also be fitted to older cars at a cost of $2000-$3000.However, it is difficult to find a radar that can fit in the car like an ACC can. The ACC system can be fitted into any vehicle, from trucks to sedans, with an installation procedure that is easy to follow. The head-end radar sensing utility may be fitted in the front grill of the car whereas; the tail- end can be drilled on to the rear bumper. 10 GHz microwaves are utilized by the radar of low power as it detects objects and obstacles within a 75 meter range.The principle of the Doppler Effect is used by the radar for the detection of moving objects in both the front and rear of the vehicle.
The cars core brings together a CISC engine along with a microcontroller which has fast response and also has the power to process analog signals. The system components used by it are minimal and has also succeeded in making the architecture of the ACC simpler.The signals received from the Doppler are analyzed before it gets fed onto the core. The heart of the core has a little microcontroller (the MC68HC908QT4, CISC) that converts the analog data into digital data. It also converts this digital data into a table of signals, which can be manually programmed, and also drives the display port to show the relative distance of the target to the driver. The tail bumper unit detects the cars coming up from behind while changing lanes. The ACC improves the reliability of the system and offers a lot of flexibility. It is of tremendous use in the freeways and city roads. The system is also cheap, selling at around $500, so probably well worth the price for those that can afford it.

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