Research On Adaptive Cruise Strategy Of Extended Range Electric Vehicle Based On Driving Behavior

With the aggravation of energy crisis and traffic congestion,taking new energy vehicles as the application carrier of intelligent technology and building a "smart electric vehicle" for the integration of new energy vehicles and intelligent driving technology has become the development trend of automobile industry.Extended range electric vehicle(EREV),as one of the new energy vehicles,has the advantages of energy saving,environmental protection and no anxiety about driving range.As an important part of the assisted driving system,the adaptive cruise control(ACC)system can effectively reduce the driving burden and improve the road usage rate.Therefore,the research on the ACC system of EREV is in line with the national strategy of intelligent new energy vehicles.At the same time,driving behavior factors are integrated into the design of the ACC system to meet the driving needs of different driver types,and optimize the economy in the process of EREV adaptive cruise.This paper conducts research from the following four aspects.(1)Power system model and energy management strategy of EREV.The main power components of the automotive power system,including drive motor,power battery,range extender,are selected,matched and modeled according to vehicle parameters and performance index of EREV.A rule-based vehicle energy management strategy is formulated,and two operating modes are divided into pure electric drive and extend range mode.The EREV simulation model is established based on MATLAB/Simulink/Stateflow.The correctness of the model and control strategy is verified by simulation through urban dynamometer driving schedule(UDDS)driving conditions.(2)Collection,analysis and identification of driving behavior data.Based on driving simulator,MATLAB/Simulink,and Pre Scan,a virtual driving platform is established to collect the actual driving data of the driver.The time headway,the reciprocal of the maximum time to collision and the average value of the absolute value of longitudinal acceleration are extracted as the characteristic parameters to reflect the driving behavior type.Conservative,general and aggressive driving behaviors are divided by K-means clustering algorithm.The back propagation(BP)neural network algorithm is used to establish an online identification model of driving behavior types,and the identification effectiveness is verified.(3)Research on adaptive cruise control strategy considering driving behavior.The ACC system is formulated by hierarchical architecture of perception layer,decision layer and execution layer.According to the time headway cluster centers of different driving behavior types obtained by the K-means clustering algorithm and the collected parking distance data,a constant time headway safety distance model suitable for different driver types is formulated.Combined with the safety,economy and comfort indexes,the constant speed cruise mode based on PID algorithm and the carfollowing mode based on model predictive control(MPC)algorithm are formulated.At the same time,differentiated MPC control parameter constraints are set for different driver types.PI control is used to convert the expected acceleration obtained by PID and MPC algorithm into driving or braking pedal signal recognized by the execution layer.(4)Simulation verification and economical cruise optimization of ACC system for EREV.The single point constant temperature control strategy based on the optimal operating point of the range extender and the power following control strategy based on the lowest fuel consumption curve are formulated for the range extender.The EREV adaptive cruise control system model considering driving behavior based on the MATLAB/Simulink/Stateflow and Pre Scan co-simulation platform is simulated and analyzed under five typical operating conditions.In order to further optimize the economy during EREV cruising,through the simulation and comparative analysis of the single mode range extender control strategy under constant speed and following mode,combined with the characteristics of different power requirements under different cruise conditions,the dual-mode switching control strategy of range extender is proposed.At the same time,considering fuel consumption and battery life,the economy of three range extender control strategies is studied under combined cruise conditions.The research results show that the EREV adaptive cruise control strategy based on driving behavior can meet the driving needs of different driver types and ensure driving safety and comfort.The fuel consumption performances vary slightly by driver types with conservative drivers being lower and the aggressive the highest.Compared with the single mode control,the proposed dualmode switching control strategy can reduce driving cost by up to 11.90%.