Simulation On Electric-hydraulic Braking System Of Battery Electric Vehicle

With the serious energy crisis and environmental pollution, people began to pay moreattention to the research of energy-saving and emission-reduction about a vehicle and theresearch of new energy automotive, represented by the electric vehicle(EV). One of theshortage of EV is the short driving range. Regenerative braking technology was consideredas an important way to solve this problem. So it is important to design a reasonableelectric-hydraulic braking system. The system can not only make sure that the brakingprocess is reliable and smooth but also can recycle braking energy.Firstly, some strategies were proposed on the basis of braking dynamics analysis of anEV, which included the braking force distribution strategy of front and rear axles, thecontrol strategy of motor regenerative braking, the control strategy of ABS and the vehiclebraking. Secondly, the original hydraulic braking system was improved. According to theprinciple of various main components of the braking system, some models were establishedbased on the AMESim simulation platform, such as the braking pedal model, vacuumbooster model, braking master cylinder model, braking wheel cylinder model, ABS modeland so on; the other models were established based on the Matlab/Simulink simulationplatform, such as the vehicle model, motor regenerative braking model, the braking forcedistribution model, tires model, ABS ECU model and so on. Together with these models andwork principle of various braking system, three kinds of braking system model were built,which are the model of conventional hydraulic brake system, hydraulic ABS braking systemand electric-hydraulic parallel brake system.Then, simulation test of these three modelswere respectively carried out on different road and braking conditions. In order to fully takeadvantages of the braking system and avoid their deficiencies, an electric-hydraulic seriesABS braking system was designed and the simulation model was built. Finally, simulationtest of the system was carried out, and the results indicated that the vehicle could shortenthe braking distance, its direction stability is good also, the wheel will not be lockedcontinuously; and its energy recovery effect is obvious. So braking performance of thisbraking system is the best of all systems, the design purpose has been reached.