Antilock Brake Control System for Four-Wheel-Drive Electric Vehicle with Electro-hydraulic Braking based on Precise Control of Hydraulic Braking Force

摘要

With the objective to regulate hydraulic pressure accurately by controlling high speed on-off valve (HSV), finite element models are parameterized based on measured parameters of an ABS hydraulic actuator unit (HCU). The data that reflects transient electromagnetic characteristics of HSV is selected with finite element numerical simulation. Taking full advantage of those data, accurate physical models of HSV are built with other parts of hydraulic braking system. Then a new system structure is proposed to control hydraulic pressure. Not only do simulation results show ideal control effect, but also hydraulic braking system can be controlled under arbitrary input signal. Accordingly, hydraulic braking force can achieve fine regulation. Finally, the hydraulic braking system is utilized to design antilock brake control system for four-wheel-drive electric vehicle with electro-hydraulic braking. That kind of system is established on the basis of hierarchical control structure. By what is called a frequency assignment approach, the lower controller coordinates the total braking torque, which is calculated by sliding mode control algorithm in the upper controller. During braking force distribution, motors execute the higher frequency torque commands, while hydraulic system responses for the lower frequency ones. System's effectiveness is validated under emergent braking based on AMESim-Simulink co-simulation.