Research On Optimal Distribution And Consistency Control Of Braking Force For Electro Hydraulic Composite Brake System

The regenerative braking technology of the electro hydraulic composite brake system is an important way to improve the energy efficiency of the electric vehicle and increase the driving miles of the vehicle,which is the restraint of development of the electric vehicle.There are two key problems of research for the electro hydraulic composite brake system of vehicle,which is how to find the optimal distribution ratios of front and rear axles' brake force,as well as regenerative braking and hydraulic braking,and based on this,achieve braking force consistency between electric and liquid brake systems.Therefore,this paper pursue research mainly focuses on these two key issues,and the main research contents are as follows:First of all,establish a vehicle dynamic model and tire model and the model of electrohydraulic composite brake system containing regenerative braking and hydraulic brake,which include motor model,inverter model,brake pedal model,brake master cylinder model,accumulator model,solenoid valve model and brake wheel cylinder model.Secondly,this paper presents the evaluation index of the braking energy recovery rate,brake pedal sensation,braking efficiency and put those as the evaluation of the electro hydraulic composite brake system,and find the optimal braking force distribution ratio of front and rear axles' brake force,regenerative braking and hydraulic braking of electric vehicle electro-hydraulic composite brake system global intelligent optimization by multi-objective particle swarm optimization algorithm to achieve good braking performance and higher energy recovery efficiency.Finally,in order to ensure that the driver obtains a natural,no obvious difference in the consistency of braking feeling,this paper design a regenerative braking and hydraulic braking sense consistency controller,maintain the change rate of braking force is constant when the brake mode is switched on by using motor braking force to compensate the lag of the hydraulic brake system.The research content of this paper can provide theoretical basis and technical support for the design and development of automotive electro hydraulic composite brake system.