| The development of vehicle has aggravated energy shortage and environmental pollution while provided much convenience for human.Electric vehicle has received a lot of attention because of its wide range of energy sources and low emission.Short driving mileage and high electricity consumption are key factors limiting the promotion of electric vehicle.Regenerative braking is an effective way to extend driving range for it can recycle braking energy.In addition,Regenerative braking has fast response and accurate control,however hydraulic braking is needed to compensate the required braking torque.To achieve cooperative control of regenerative braking and hydraulic braking,improve vehicle performance,the dynamic distribution strategy of the rear wheel drive full-electric vehicle is studied in this paper.Firstly,the vehicle dynamic model is built according to the vehicle dynamical system configuration.And the magic formula model is applied to express the relationship between tire longitudinal force and slip ratio.After analyzing the principle of regenerative braking system and hydraulic braking system,their dynamic models are established.Also the battery model is built and current integral method is used to calculate SOC.Then,this paper investigates current research actuality as well as the research status of automobile manufacturers,universities and research institutes on regenerative braking system.We analyze the typical cooperative braking strategies and improve the power distribution mode of the front and rear wheels according to the characteristics of the rear wheel driven full-electric vehicle.Then,the model prediction controller is applied to adjust the distribution of braking force torque and friction braking torque.In order to improve performance of the antilock brake system(ABS),a synovium variable structure controller is used,and it is integrated with the model predictive controller to optimize the ABS system.Thirdly,the whole system model is built on Matlab/Simulink platform and simulated under different conditions.The experimental results show that the composite braking system based on the model predictive control can enhance the braking capacity and improve the capacity utilization of the vehicle,whether it is the general braking condition or the ABS system.Finally,based on the dSPACE platform,the prototype simulation platform of electro-hydraulic composite braking system is built and the prototype simulation test is verified.The real-time simulation results are basically consistent with the offline simulation results,indicating the effectiveness and feasibility of the proposed regenerative braking control strategy for pure electric vehicles. |
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