23-03-2012, 01:31 PM
Adaptive Cruise Control system
HACC.doc (Size: 38 KB / Downloads: 98)
Introduction
Adaptive Cruise Control systems automatically adjust a cars speed to maintain a safe following distance. This is done with the help of automatic transmission system. This new technology, uses forward – looking radar, installed the grill of a vehicle ahead of it. Adaptive Cruise Control system uses automatic transmission system by which system can automatically adjust speed in order to maintain a proper distance between vehicles in same line. This is achieved through Headway Sensors, Digital Signal Processor and Longitudinal Controller. If the lead vehicle slows down, or if another object is detected, the system sends a signal to the breaking system of engine to decelerate. Then when the road is clear, the system is restored. The systems are being enhanced to include collision warning capabilities that will warn drivers through visual and also audio alarm. This paper explains the Adaptive Cruise Control system in detail that creates comfort and safety to all passengers.
Necessity of cruise control
A good Adaptive Cruise Control system accelerates aggressively to the desired speed without overshooting, and then cruise control system maintain that speed with little deviation no matter how much weight is in the car, or how steep the hill you drive up. Controlling the speed of car is a classic application of Adaptive Cruise Control. Every thing on average, at least one person dies in a crash. Auto accidents injure at least 10 million people every year, two or three million of them seriously. Adaptive Cruise Control will provide the safe way of driving and will probably reduce the chances of accidents. ACC components The Automatic Cruise Control system is build as distributed system using common Electronic Control Units (ECUs) plus one additional ECU, which contains the range sensor and the automatic cruise control components. The combined range sensor and ACC controller is mounted in front of a car. A Man Machine Interface (MMI) includes all the interfaces of ACC system to the driver, the operation switches, the display and the pedals (accelerator, brake). An electronic brake control system is optional depending on the characteristic conditions and in unsteady traffic conditions.
Cruise control module
The cruise control module has to do three things. First it remembers the speed you set. It stores this set speed until you change it or turn off the ignition. Next it takes the speed signal from the vehicle speed signal from the vehicle speed sensor and compares it to the set speed. Lastly it sends a pulse signal to the actuator. The brain of a cruise control system is a small computer that is normally found under the hood or behind the dashboard. It connects to throttle control.
Instrument cluster with distronic display It displays stored speed, distance between the cars and other important indication.
Brake control Active brake control in based on the hydraulic systems used for standard traction control (4WD-ASR) or VDC and does not require a smart booster. This system allows quite and comfortable deceleration control and can automatically switch to ABS.
Radar system and multi tracking system This system has extensive capabilities to detect multiple objects within the narrow range or fixed range and send the signal to micro processing unit to compare parameter.