Modeling And Simulation Research Of Collision Avoidance Control System For Electric Vehicle

As the earth’s resources and environmental issues have become increasingly prominent,many countries and vehicle companies have pay more attention to the research of new resource vehicles.Security can never be ignored in the design,manufacture or use of automobiles. Collision avoidance system is an important content of advanced automobile security technology based on intelligent transportation system.The research of collision avoidance system of electric vehicle is a combine of these two frontier and well have great significance in security and energy utilization efficiency of automobiles.The study object of this dissertation is a collision avoidance system for electric vehicle and the study is based on vehicle dynamics,system modeling,theory of electric vehicle and control engineering. This paper covers the system dynamics modeling,the estimation of safety distance and control algorithm of the collision avoidance system of electric vehicle.Firstly,the outline of collision avoidance system of electric vehicle is established based on the research of collision avoidance system of traditional vehicle. The key technologies needed in the system are determined based on the system outline.As the subject of control,dynamics modeling of electric vehicle is needed in this dissertation.A vehicle model contains a seven DOFs vehicle model,a motor model,a battery model,a dugoff tire model and a brake actuator model is established. An inverse longitudinal dynamics model is built in order to realise the control.An inverse brake model is built based on parallel braking force distribution strategy.An adaptive cruise car-following distance model based on time headway and a collision avoidance safety distance model based on braking process are built to meet the different control needs.Based on all the research mentioned above,the control system of collision avoidance system is developed.Hierarchical control is used in the design of control system.The transfer function of the vehicle model is got through model matching.Based on the transfer function,a?H robust lower-layer controller contain a feed-back compensator and a feed-forward compensator are designed.The upper-layer controller are based on different control function.The cruise upper-layer controller is designed based on PID control and the adaptive cruise upper-layer controller is designed based on FSMC(Fuzzy Sliding Model Control).Finally, the simulation models are built in matlab/sumulink environment.The simulation results indicate that the vehicle model and the control strategy not only can realize the control function well but also improves the energy efficiency and has great significance in the late research of active safety system of new energy vehicle.