Research On Active Collision Avoidance Control Of Vehicle Based On Vehicle-Vehicle Cooperation

Traffic congestion and traffic safety are two major problems in the field of transportation.Intelligent transportation plays an important role in improving traffic safety level and alleviating traffic congestion.With the rapid development of wireless communication technology,vehicle-vehicle collaboration technology has become a hot topic in intelligent transportation technology research.Active collision avoidance system,as an important part of advanced automobile safety technology,improves driving safety and promotes the development of intelligent transportation.Therefore,it is of great significance to study the collision avoidance control system which combines vehicle collaboration technology with active collision avoidance technology.This paper mainly studies the longitudinal collision avoidance system of docking pavement and the active collision avoidance system of single highly attached pavement based on vehicle-vehicle cooperation.Firstly,in the paper,the vehicle dynamics model is established,including vehicle non-linear seven-degree-of-freedom model,tire model,vehicle linear two-degree-of-freedom model and inverse dynamics model,and estimates road adhesion coefficient based on Extended Kalman Filter?EKF?,then establishes traditional braking safety distance model,and the model can not guarantee longitudinal collision avoidance on the docking road surface vehicle safety and reduce road utilization,which is verified by the simulation.According to the boundary conditions of vehicle lane-changing,lane-changing trajectory planning is carried out.Combining with the comfort and efficiency evaluation index of lane-changing,a normalized evaluation function is established to select the optimal lane-changing trajectory.Combining with the critical conditions of collision between front and rear vehicles,a safe distance model for lane-changing is established,and the lane-changing conflict on the two lanes of the single road surface is analyzed.Aiming at the collision avoidance scenario of docking pavement,a dynamic longitudinal safety distance model is established based on docking pavement and the validity of the safety distance model is verified under conservative and risky modes respectively.Then,on the basis of dynamic safety distance model,the longitudinal collision avoidance control strategy of docking pavement is established,and the longitudinal-to-downward controller based on PID is designed,including piecewise longitudinal controller and slip-rate target longitudinal controller.The control effect of anti-lock braking?ABS?system on different pavement is simulated and verified.Finally,based on the joint simulation platform of CarSim and MATLAB/Simulink,the effectiveness of the docking road collision avoidance system based on vehicle-vehicle cooperation is verified.The simulation results show that,compared with the control strategy based on the braking safety distance model,the vehicle-vehicle cooperative longitudinal collision avoidance control system not only improves vehicle safety,but also increases road utilization ratio on the docking road with the change of road adhesion coefficient.Aiming at the collision avoidance scenario of single high adhesion road,the critical state of braking and steering collision avoidance is firstly analyzed,and the critical collision avoidance safety distance of vehicle braking and steering is determined by combining vehicle braking deceleration and optimal lane changing trajectory.Then,in order to determine the vehicle's dangerous working conditions,two evaluation methods are designed,namely,the risk assessment model based on fuzzy reasoning and the risk area assessment based on the reciprocal of collision time(TTC^-1).On this basis,a cooperative active collision avoidance control strategy is proposed.A steering controller is designed based on preview and follow theory,and its effect of path tracking control is simulated and verified.A vehicle-vehicle cooperative lane-changing model is established and the optimal lane-changing trajectory is planned.Finally,CarSim,PreScan and MATLAB/Simulink joint simulation platform are built to verify the effectiveness of the vehicle-vehicle cooperative active collision avoidance system on a single highly attached road surface.The simulation results show that compared with single full braking control strategy based TTC^-1,the active collision avoidance system integrated braking and steering improves vehicle safety and driver comfort.The hardware-in-the-loop real-time simulation platform is built to verify the effectiveness of vehicle-vehicle cooperative lane-changing collision avoidance control.The real-time simulation results show that the vehicle can ensure the safety and stability of vehicle driving in cooperative lane-changing control.