Research On Road Condition Recognition Of Active Anti-collision Warning System

Active Collision Warning System makes use of sensor technology and modern information technology to access external information, according to vehicle condition and road conditions which determines whether there are security risks. Then it will take the appropriate measures to control the car automatically and to make the vehicle avoid the risk and ensure the safety of vehicles, to minimize or reduce traffic accidents and improve traffic safety.Active Collision Warning System is divided into three major parts: Environment recognition system, Security status determination system, Control execution system. Environment recognition system is used to identify vehicle parameters(throttle position signal, the signal of the vehicle speed and acceleration signals in real, etc.) and road condition parameters (road type, road signs signals, other vehicles, pedestrians and obstacles in front of itself,etc). And it will measure the relative velocity information to achieve the identification of Internal and external environment. Security status determination system makes use of identified information environment recognition subsystem provided to determine the state of the vehicle, Mainly calculation and determination whose degree of the risk on the environment determines the model state the current dates fitted, to give directions to Control execution system, and to make the results of calculations and determinations to interact with the driver through Human Machine Interface, Or the driver can also transfer the information they need to Signal processing system for inquiring provide the driver with timely and effective state information as a reference. Controlling execution subsystem accepts judged information which the Security status determination subsystem has provided, and alert the driver in a dangerous state, If the driver have not any action in a certain pre-set period of time, to achieve the required state of Charged target by the system control mode automatically, and to avoid delaying the driver's operation and to ensure traffic safety; If a collision is unavoidable, it will be called passive safety related measures.Road identification and condition identification are critical in Environment recognition subsystem of Active Collision Warning System, the recognition of road type is the most important in road Recognition, The most typical expression of road surface type parameters is the road adhesion coefficient, But it is difficult to estimate the road adhesion coefficient, Road adhesion coefficient is directly related to the size of braking distance, And the purpose of estimating the road friction coefficient is to calculate the braking distance in the Active Anti-collision Warning System. Therefore, this study's focus is shifted to building up the braking distance model. The core content of this article is to establish a braking distance model in the drive process, First it needs to create dynamic model of vehicle, set vehicle parameters ideally, establish the engine model, Transmission model, Transmission system model, Driving wheel dynamics model, Driving wheel dynamics model and the vehicle dynamics model; which is Based on the vehicle dynamics model, establishing the braking distance model the process of driving, designing Block Diagram of simulation, analyzing the results of running simulation.