Research On Electro-Hydraulic Composite Regenerative Braking Control And ABS Control For Four-axle Electric-wheel Vehicle

Electric vehicles have developed rapidly in recent years,as a special electric,the electric-wheel vehicles not only have the advantage as electric vehicles,but also can exert the advantage of in-wheel motor.As a result,the electric-wheel vehicles have a promising future It will do the research of braking system based on the four-axle electric-wheel heavy-duty electric vehicle in this paper.In this paper,it improved and redesigned the braking system of four-axle electric-wheel heavy-duty electric vehicle according to its features.It designed a new type hydraulic brake control unit and did the research on the multi-axle vehicle's braking force distribution.Afterwards the braking energy recovery control strategy and anti-lock control strategy has been designed.Then it established simulation platform and finished the simulation experiments of the control strategies.Finally,a HIL test experiment for testing the new type hydraulic brake control unit has been completed.The specific research content is consisted by these four parts as followed1.It analyzed the factors which affect the performance of the vehicle braking system and the braking energy recovery.It improved and designed the hydraulic brake system according to the structure and features of the four-axle heavy vehicle,and determined the overall structure of the electro-hydraulic composite braking system.Then it established of the four-axle vehicle dynamics model of the braking process,and designed the braking force distribution scheme of the four-axle vehicle.The braking energy recover control strategy and motor-hydraulic braking force distribution strategy were designed based on the electro-hydraulic composite braking system which was established.Finally,the brake anti-lock control strategy is designed based on the controlling pure motor2.It built a simulation platform for testing the control strategy.It used TruckSim to build a four-axle vehicle model,AMESim to build a hydraulic brake control unit,a motor braking unit,and an energy storage device,and the braking energy recover control strategies and antilock braking control strategies were built in Simulink.Afterwards the accuracy and feasibility of the hydraulic braking control unit module and the motor braking module unit were simulated for their accuracy and feasibility in AMESim.Also,with TruckSim,the ideal braking force distribution strategy was tested.The three-platform joint simulation experiment was carried out to verify the braking performance and energy recovery capability of the electro-hydraulic composite energy recovery braking system.It used different initial speeds and braking deceleration on the road with different pavement adhesion coefficient.Linear regenerative braking conditions under dynamic strength.Then it used different road with low pavement adhesion coefficient to test performance of the anti-lock braking system.The results show that the four-axle energy recovery braking system has a good braking efficiency and energy recovery ability,and it can make the wheel slip rate near the ideal slip rate which means a good anti-lock ability3.Then,it determined the evaluation index of energy recovery braking,and the operating condition of the energy recovery braking simulation experiment4.At last,it performed the HIL experiment on new hydraulic brake units,which used ESC hydraulic control units as a control prototypes which controls booster valves This experiment verified the response speed and accuracy of the new hydraulic brake unit,and determined the optimal duty cycle of the booster valve.