Research On Vehicle Active Collision Avoidance Control System

As an active safety technology of vehicles,the active collision avoidance control system can control vehicles to achieve collision avoidance by means of longitudinal braking or steering lane change,which plays an important role in reducing traffic accidents and improving driving safety.In this thesis,the active collision avoidance technology is studied,and the Car Sim /Simulink simulation platform is used to verify the effectiveness of the designed system.This thesis mainly research contents include:(1)for vehicle longitudinal braking collision avoidance and turning lane changing control demand of collision avoidance,vehicle inverse engine model is established,the inverse model of brake system and vehicle dynamics model,tire vehicle driving safety distance model is studied.The longitudinal critical braking distance and the allowable steering lane change distance are determined.The switching logic of longitudinal braking and steering lane change in the active collision avoidance control system is designed.(2)longitudinal braking collision avoidance system is designed.An upper controller based on the principle of fuzzy control is established,which can generate the desired deceleration according to the vehicle driving condition.The lower level controller based on PID algorithm is designed at the same time,according to corresponding braking control volume reduction speed deviation,passed to the actuator,realize vehicle longitudinal braking collision avoidance.(3)The steering lane change collision avoidance system is designed.The quintic polynomial curve is selected as the lane change path to avoid collision,and the path parameters are determined according to the boundary conditions.A vehicle steering lane changing path tracking controller based on MPC algorithm was designed to solve the multi-constraint path tracking objective function and obtain the expected increment of front wheel rotation Angle,so as to complete steering lane changing to avoid collision.(4)Build a co-simulation platform,and use a variety of working conditions to simulate and analyze the longitudinal braking collision avoidance system and steering lane change collision avoidance system designed in this paper.The simulation results show that the longitudinal braking system can reduce the braking speed and avoid the collision.And turning lane changing system can make vehicle tracking the desired lane changing path,realize the function of collision avoidance to flow,and good stability.