Research On AEB Control Strategy For Four-wheel Independent Drive Electric Vehicle

With the gradual development of automobile industrialization,resource shortagebecomes more and more serious,causing a global energy crisis,which also intensifies the pace of the development of new energy vehicles.Four-wheel Independent Drive Electric Vehicle(FWID-EV)has gradually become a research hotspot in the new energy Vehicle industry due to its advantages of less pollution,low energy consumption,compact structure and independently controllable wheel torque.Subsequently,the phenomenon of vehicle collision and rear-end collision has also become a safety problem in today's traffic.In order to avoid the car crash in an Emergency,this paper designed an Autonomous Emergency Braking(AEB)Control strategy based on the FWID-EV platform.Based on the Model of the car's longitudinal motion state and combined with the Model Prediction Control(MPC)theory,the safety of the car's longitudinal motion was improved.First,FWID-EV simulation platform including hub motor model,powertrain,sprung mass and tire model was built.The hub motor model was built in MATLAB/Simulink,and the powertrain,reed mass and tire model were modified in the dynamics software Car Sim to match the unique chassis structure of FWID-EV.Finally,a joint simulation platform based on MATLAB/Simulink and Car Sim was formed.Secondly,aiming at the longitudinal motion direction of the car in emergency,the critical safe distance model based on variable time interval is built and the whole flow of AEB controller is designed.The longitudinal anti-collision performance and ride comfort of the car are comprehensively considered,and the AEB control strategy based on MPC theory is designed by introducing the TTC to constrain the variables.Rolling optimization of multiple performance indexes under MPC framework not only ensures the real-time performance of the control algorithm,but also realizes the cooperative control of multiple performance indexes to meet the driver avoiding collision charac characteristics.Thirdly,in view of the torque distribution strategy of vehicles in emergency situations,in consideration of motor power loss,torque change and road adhesion coefficient,the objective function and constraint conditions are constructed to form a highly complex nonlinear optimization function,so as to optimize the energy loss and control stability of FWID-EV.The improved particle swarm optimization algorithm is used to solve the optimization problem.Finally,the experimental verification of AEB control strategy is carried out on the FWID-EV simulation platform.The experimental results show that the AEB control strategy based on variable time headway designed in this paper can effectively pass the AEB test standard and ensure the anti-collision characteristics and ride comfort of the vehicle,accord with the driver avoiding collision characteristics.The optimal torque distribution strategy proposed in the emergence braking condition can ensure the motor drive performance requirements.Based on the FWID-EV simulation platform,this paper USES the MPC control theory to design the AEB control strategy,which can meet the performance requirements of the AEB control system,ensure the crudity-proof and ride comfort of the vehicle,and provide technical reference and support for the promotion and application of FWID-EV.