Research On Electro-hydraulic Hybrid Brake System Combined With ABS Of Electric Vehicles

Global problems such as environmental pollution and energy storage becomeincreasingly serious. Automobile, as one industry intimately related to energy andenvironment, has to achieve less pollution and high energy utilization. For these havebecome critical issues to keep a good development. Research on hybrid-electricvehicles, pure electric vehicles and plug-in electric vehicles has become a focus tosolve above problems recently. Braking energy recovery, which means capture somebraking energy produced by drive axle using regenerative braking system and theenergy is stored in battery, is one of critical new technologies in electric vehicles.Typically, regenerative braking system doesn’t have the ability to satisfy driver’sdemand for brake. As a result, hybrid regenerative brake becomes a key technology toachieve both braking performance and energy recovery.A new structure of electro-hydraulic hybrid brake system applied to electricvehicles is put forward on the basis of understanding EHB (Electronic HydraulicBrake System), hybrid regenerative brake and braking energy recovery technologiesat home and abroad. By adding active hydraulic control module to the traditionalABS (Anti-lock Braking System), the new structure can apply hydraulic brakingforce actively and lay a foundation for optimum energy recovery strategy application.By way of analyzing brake working mode and demand for brake, the match ofparameters in active hydraulic control module is analyzed. Single-circuit hydraulicbrake system is simulated using MATLAB/SimHydraulics to verify the feasibility ofthe new brake system.Then, the paper goes into details of control strategy and method for new brakesystem. Vehicle braking control strategy is developed on the basis of analyzingdriver’s brake intention and factors affecting regenerative brake system. The hybridbrake control unit, hydraulic brake control unit and motor control unit coordinatetasks mutually to achieve apply regenerative and hydraulic braking force on eachwheel accurately. Both braking performance and energy recovery maximization takeninto consideration, a layered braking force distribution strategy based on drivingparameter estimation is proposed, which satisfy both emergency brake andnon-emergency brake. Combined with control strategy, vehicle model andregenerative brake system model are built using MATLAB/Simulink to verify brakesystem and regenerative system performance. By using ADVISOR, braking forcedistribution strategy simulation is conducted to validate energy recovery effect intypical driving cycles.Last but not least, a controller for ABS module is developed, which canimplement ABS valves and bump motor control, data acquisition and data transmission with the computer. A bench is built to test dynamic effect of ABS valvesand verify its performance in active control of hydraulic braking force.