Research On Multi-objective Optimization Design Of EV Electro-hydraulic Composite Braking System Based On Co-simulation

Due to the comprehensive problems of the energy and environment, the automobile industryneeds to make changes urgently, which is to change the dependence on the oil and other unsustainableenergy. Electric vehicles with clean, energy-saving features have incomparable advantages in the newenergy vehicles. Compared with the conventional hydraulic braking system, the EVs electro-hydrauliccomposite braking system with regenerative braking capacity can effectively recover energy duringvehicle braking. It can not only improve the braking performance of the vehicle, but also make up forthe defect of insufficient travel distance of electric vehicles, and becomes a key energy-savingtechnology in the development of electric vehicles.The study of composite braking force distribution strategies and braking force control strategiesare the key aspects of electro-hydraulic composite braking system, to gain braking energy as much aspossible on the basis of braking stability. Therefore, a multi-objective optimization method to thecontrol strategy of EVs electro-hydraulic composite braking system was proposed, and co-simulationanalysis and semi-physical experimental verification of EVs electro-hydraulic composite brakingsystem were conducted after analyzing the research status home and abroad. According to these ideas,this article discussed the following issues:（1）Introduced the structural characteristics and working principle of the electro-hydrauliccomposite braking system, and completed the selection and parameters matching work of the keycomponents of EVs electro-hydraulic composite braking system. And also established the model andconducted a simulation analysis of its dynamic response for the three-way proportional pressurereducing valve in the AMESim software environment.（2）On the basis of analyzing and comparing of typical braking force distribution controlstrategies, an appropriate control strategy for the EVs electro-hydraulic composite braking system hadbeen determined. And the multi-objective genetic algorithm has been introduced to optimize the keyparameters of the control strategy with the optimization objectives of braking stability and brakingenergy recovery efficiency.（3）An EVs electro-hydraulic composite braking system co-simulation platform had beendesigned based on Matlab/Simulink and AMESim environment. The key component models ofelectro-hydraulic composite braking system were established in AMESim environment, includinghydraulic braking system, motor, battery, etc. At the same time, the control algorithm models were established in Matlab/Simulink environment, including the required braking force model, regenerativebraking force model, electro-hydraulic braking force distribution model and anti-lock control model,etc. Then a co-simulation analysis of electro-hydraulic composite braking system under the drivingcycle has been conducted.（4）In order to verify the validity of the simulation results, a semi-physical test bench of EVselectro-hydraulic composite braking system was built. Through the designing of hardware andsoftware for the test bench, the verification for the dynamic response of the solenoid valve and thepressure control of the wheel cylinder had been done. These experiment results could provide areference to the further study of EVs electro-hydraulic composite braking system.