Research On Control Strategy Of ACC System Of Pure Electric Vehicle In Urban Road Conditions

With the continuous growth of car ownership,energy shortage,traffic congestion,frequent traffic accidents and other issues have become increasingly prominent.In order to solve these problems,new energy vehicle technology and automobile active safety technology have become the research hotspot of automobile industry.On the other hand,China’s urbanization intensifies,urban roads become the main scene of people’s daily driving.Therefore,it is of great significance to study the adaptive cruise control system control strategy and algorithm in urban road conditions.The main contents of this paper are as follows:(1)Based on the analysis of the expected vehicle spacing strategy considering the self driving speed and the relative speed of two vehicles,the expected vehicle spacing strategy considering the acceleration of the vehicle in front of the vehicle is formulated,and its stability in steady-state following the vehicle is proved.According to whether there is an effective target vehicle in front of the vehicle and whether the driver has the intention of actively controlling the vehicle,the ACC system is divided into constant speed cruise mode In the following mode,the model predictive control algorithm which can be used for multi-objective optimization in the following driving mode is adopted;in order to make the ACC system switch reasonably between different working modes,the switching strategy and driving mode of constan t speed cruise and following driving mode are formulated respectively According to the common curve conditions in urban road,the control strategy is optimized,and the effective target recognition algorithm and safe speed control strategy are formulated.(2)On the basis of summarizing the existing lower control scheme of ACC system,the lower control scheme of pure electric vehicle ACC system is designed,and the lower control layer and executive layer model of pure electric vehicle ACC system are established;the vehicle reverse longitudinal dynamics mode is established by analyzing the longitudinal force of the vehicle;the pure electric vehicle drive system based on permanent magnet synchronous motor is established and energy is considered In order to make the vehicle switch between driving mode and braking mode reasonably,the switching strategy of driving mode and braking mode of pure electric vehicle is formulated.(3)In order to verify whether the control strategy and algorithm of the upper and lower layers of ACC system are reasonable,this paper establishes the simulation model of ACC system through Simulink and Car Sim,and carries out simulation on the common conditions of cruise control,car following,stop-go,cut in,cut-out and curve conditions in urban road conditions;in the condition of Cruise control,through comparing with the simulation results of PID control algorithm,it is concluded that The control algorithm used in this paper has a better adaptati on to different cruising speeds;By analyzing the simulation result,it can be concluded that the control strategy and algorithm designed in this paper are more reasonable,and have a good effect on urban road conditions Adaptation.