Research On Modeling And Simulation For Vehicle Cruise Collision Avoidance And Pre-warning System

With continuous increasing of vehicle population in China,and the number of traffic accidents have also increased,the technology research which related vehicle active safety has also becoming more and more significant.Its application is of great significance for improving traffic safety and reducing collision accidents.At the same time,the "Made in China 2025" mentions the development requirements of automotive intelligent transportation too.The research of cruise collision avoidance and pre-warning system is belongs to the active safety of vehicles in this paper.In this paper,vehicle cruise collision avoidance and pre-warning system is taken as a subject investigated,the study is based on vehicle dynamics model and control theory.Consider complex road driving conditions,and according to different control functions,the global design scheme is determined.The component structure and functional mode division of the system are given,the comfort index of the control system is graded and quantified.Then the vehicle dynamics model is established by CarSim,the data of the engine throttle opening characteristic map is analyzed,and CarSim simulation process is used to collect the maximum deceleration of the vehicle at different initial speeds.According to the switching logic algorithm,the throttle opening/braking force control switching strategy is designed,and then the vehicle inverse dynamics model is established.Based on the actual braking characteristics of the vehicle,combined with the traffic requirements and the principle of collision avoidance,the principle of determining the safety distance is summarized in this paper.Based on this principle,a critical pre-warning distance model and a critical braking distance model based on the driver's braking characteristics are designed.Specifically,the driver's braking operation characteristics is tested and the relevant data is analyzed,then the safety distance model according to the driver's brake operation characteristics is obtained by data fitting used the least squares method in Matlab,a hierarchical pre-warning algorithm is design,then the safety distance strategy of adaptive cruise control is analyzed and confirmed.The upper and lower controllers are designed by hierarchical control,and the fixed-speed cruise controller based on PID control principle and the adaptive cruise controller based on fuzzy control are designed according to different control function modes under different traffic conditions.The collision avoidance mode upper controller is designed based on the critical braking distance model of the driver's brake operating characteristics.Considering the strong nonlinearity of vehicle dynamics,a fuzzy PID lower controller is designed,which has good adaptability by verification.Under the different working conditions,and the co-simulation verification is done by CarSim-Simulink,the simulation results show that the vehicle cruise collision avoidance and pre-warning system can achieve the collision avoidance and the fixed speed-adaptive cruise control function,the driving safety is greatly improved,and the driver's operating intensity is reduced under certain circumstances.Based on the comfort index,the control strategy in this paper also has a certain emphasis for driving comfort.It will help to further promote the practical application of the vehicle cruise collision avoidance and pre-warning system.