Research On Automatic Emergency Braking Method Under V2V Conditions

At this stage,China’s vehicle production and manufacturing level has moved to the forefront of the world,and the frequency of traffic accidents is increasing as the number of cars per capita continues to rise.With the development of intelligent driving technology,especially vehicle-to-vehicle communication technology and automatic emergency braking systems,the frequency of traffic accidents has been effectively reduced.Therefore,it is possible to realise the collision avoidance function by combining the two functions of the automatic emergency braking system and V2 V technology in order to ensure driving safety.In this dissertation,the automatic emergency braking system is studied on the basis of V2 V,and an AEB system for straight and constant curvature curves is established,while the vehicle stability of vehicle braking in curves is considered.Finally,the system is modelled and simulated and the results analysed in MATLAB/Simulink and Car Sim platform modelling.The dissertation is conducted as follows.Firstly,the vehicle validation model,the vehicle inverse dynamics model and the controller model were constructed.The accuracy of the model is checked by inputting deceleration signals to observe the acceleration,speed and braking pressure changes of the vehicle to ensure the design of the control algorithm at a later stage.The working principle of vehicle V2 V wireless communication technology in intelligent assisted driving vehicles is introduced,and the emergency braking system is developed based on it.By analysing the braking distance,the factors affecting vehicle braking are identified.And the collision residual time TTC under general conditions is improved to obtain the enhanced residual collision time ETTC considering relative acceleration.for the characteristics of emergency braking of vehicles on curves,the collaborative collision warning system ICCWS is established to solve the problem of unrealistic relative distance on curves,and the upperlevel control model applicable to both straight and curved roads with ETTC as the control target is realised.Then,taking emergency braking in bends as an entry point that may lead to instability,the vehicle motion state parameters are analysed to find out the factors affecting vehicle stability,and an ESC stability control system model is established.By analysing the stability control system,a two-degree-of-freedom vehicle model is selected as the reference model,and the error between the true and reference values of the vehicle’s side slip angle and yaw velocity is taken as the control target.The vehicle stability control function is realised by calculating the compensation torque for the control stability through fuzzy control.The stability control basis is laid for the simulation test.Finally,the simulation test was carried out with reference to the China-New Car Assessment Program test method,and the simulation test was carried out by increasing the test speed on the basis of its standard and analysing the simulation results of the whole simulation system up to and around the bend.The simulation results were satisfactory and the relative distance after braking was controlled at around 1.5m,which enabled the obstacle avoidance function to be achieved.The reliability and practicality of the overall model and control algorithm are verified,and the automatic emergency braking function under V2 V conditions is realised,verifying that the model has certain engineering significance.