Ride Comfort Control During Mode Switching Of Electro-hydraulic Hybrid Braking System

Due to the different time-domain response characteristics of the hydraulic braking system and the motor braking system,in the process of switching between different braking modes,the tracking error between the actual braking moment and the target braking moment is large,leading to a large braking impact degree,which affects the ride comfort of the vehicle braking process and the driving experience of the driver.At the same time,the addition of motor braking will also interfere with the traditional hydraulic anti-lock braking system.How to develop the anti-lock control strategy of electric and hydraulic composite braking system is of great significance.In this paper,the following studies are carried out for vehicles driven by hub motor:The mathematical model of electric and hydraulic composite braking system was built in Simulink,and the target vehicle model was established in Carsim.The composite braking system model in Simulink was connected with the vehicle model in Carsim,and the composite braking system vehicle model driven by hub motor was built as required by the cost analysis.The working modes of the composite braking system in the process of conventional braking and anti-lock braking are divided,and the intervention prediction module of the hydraulic braking system,the dynamic compensation module of the electric mechanism and the dynamic exit prediction module of the electric mechanism are formulated to solve the problem of large impact degree of the vehicle in the process of braking mode switching.In the logic threshold method based on the road recognition is proposed on the basis of logic threshold control strategy of library,and connecting with the threshold method library control strategy with PID control strategy for their own advantage,puts forward library logic threshold method with PID control strategy,could be divided into low road adhesion conditions attached,high echo in the attached,and combined with the characteristics of two braking systems,Formulate the corresponding anti-lock braking strategies respectively.Based on the established Car Sim and Simulink co-simulation platform,the proposed control strategy is simulated and verified.The simulation results show that: in the conventional braking process,the braking impact degree is reduced by 28.5%,30.03% and77% respectively in three typical switching processes after the coordination control is added.The improved threshold base control strategy can reduce the braking distance of vehicles.Compound braking can ensure the safety requirements of vehicle braking when anti-lock braking is carried out on high adhesion road or medium adhesion road.