The Collision Warning System of the Automations
The Collision Warning System of the Automations
There are three main collision warning systems all over the world at the present time. First is the active collision warning system, which can alarm when it inspects the danger. The system has been applied in the heavy trucks and bus in America; second is the adaptive cruise control system, which can implement the collision warning control under the simple transportation situation. Some high class vehicle has utilized this technology; third is the intelligent control system of mix mode car, which can be used in the complex transportation, especially the traffic circumstance in the city. This system is used by connecting the stop and go system to improve the practicality of the system. Most of the collision warning researches are focusing on the longitudinal control. There are several key technologies in the research, such as the recognition of the objective vehicle, the obtainment of information, safe distance mode and so on.
The distance measurement is the key to driving circumstance recognition. The ultrasonic, infrared ray, laser, machine vision and radar technologies are the main methods to measure the distance. The radar technology is considered to be the best way of controlling in the active collision warning system of automobiles, because it has high accuracy and real time performance. The distance measurements in many companies become practical nowadays. The judgment of safe distance utilized the algorithm. The Japanese researcher established the driver based safe distance mode which is not suitable for the feeling of driver. Therefore the research of driver optimal preview longitudinal acceleration model is under development.
The upper control and under control are the two controlling methods of collision warning system. The upper control gains the current deceleration of the car by computing from the viewpoint of kinetics, while the under control method charges the throttle with automotive brake system. There are also some shortcomings need to be improved in this system, for example, it always alarm wrongly and does not take the driving characteristic of the driver into consideration; researchers simply consider the longitudinal control, ignoring the side control of the dangerous vehicle. More efforts need to be made to develop this system. The related integrated circuit is IH5040.