Reaserch On Electro-Hydraulic Composite Braking System And ABS Control Of In-Wheel Motor Driven Vehicles

The global environmental pollution and energy crisis are becoming more and more serious,and the shortage of oil has prompted the development of the automobile industry to shift the focus of the development of electric vehicles to electric vehicles,which has led to the rapid development of electric vehicles.Electric vehicles driven by in-wheel motors have the advantages of high transmission efficiency,rapid control,and high dynamics,and have become a research hotspot for electric vehicles in the future.For electric vehicles driven by in-wheel motors,there is not only the problem of low cruising range of electric vehicles,but also the problem that the introduction of motors affects the performance of the original braking system.How to improve the energy recovery efficiency of the electro-hydraulic composite braking system on the basis of ensuring the braking performance of the vehicle braking system is an important way to solve the above problems.At the same time,the introduction of the motor braking torque makes the braking system have two power sources with different control methods at the same time.When the vehicle emergency braking triggers the ABS,how to reasonably coordinate the distribution relationship between the motor and the hydraulic braking torque to improve the vehicle braking performance.It has also become a research hotspot of electric vehicle braking performance.In this paper,taking the pure electric vehicle driven by in-wheel motor as the research object,aiming at improving the braking performance and braking energy recovery efficiency,the braking force distribution strategy of the electro-hydraulic composite braking system and the antilock braking control strategy of the electro-hydraulic composite braking system are formulated.On the premise of ensuring braking performance,the energy recovery efficiency of the vehicle is improved.The main research contents of this paper include.First,the structural scheme of the in-wheel motor-driven vehicle is determined.The simulation model of the electro-hydraulic composite braking system is established,mainly including the permanent magnet synchronous motor model using dual-loop control,the hydraulic braking system model,the tire model,the motor model and the driver model,and the multiple models built are simulated and verified.Second,formulate an electro-hydraulic composite system braking force distribution strategy.The braking force relationship between the front and rear axles during vehicle braking is analyzed through the braking force distribution theory of the front and rear axles of electric vehicles,and the braking force distribution coefficient for the vehicle studied in this paper to ensure braking safety and stability is derived based on the ECE braking regulations.Taking the opening of the brake pedal as the judgment condition for mode switching,the braking force distribution strategy of the segmented electro-hydraulic composite braking system is formulated,which achieves a certain energy recovery efficiency on the basis of ensuring the braking performance of the in-wheel motor-driven vehicle.Third,formulate the anti-lock braking control strategy of the electro-hydraulic composite braking system.Based on the above electro-hydraulic composite braking system,the anti-lock braking control strategy of electro-hydraulic composite braking is formulated.For conventional anti-lock braking conditions,a compound braking anti-lock braking control strategy is formulated in which the motor braking force is maintained to the ABS stable torque region,and the hydraulic braking force is used as the anti-lock braking force to dynamically adjust the torque.For special working conditions small strength.The pure motor braking wheel locks up,and an anti-lock braking control strategy based on the logic threshold value is formulated.Fourth,simulation analysis of the braking performance and energy recovery efficiency of the composite braking system designed in this paper.According to the requirements of braking regulations,the corresponding simulation conditions are designed to verify the braking performance and energy recovery efficiency of the braking system designed in this paper.The simulation results show that the braking system designed in this paper not only has good braking performance,but also has a certain energy recovery efficiency.