Study On Electric Power Steering System Used By Battery Electric Vehicle

With good points of a simple structure, easy installation, energy saving, can improvesteering performance and driving safety, etc., electric power steering system graduallyreplaced the hydraulic power steering system. It represents the future developmentdirection of power steering systems. Battery electric vehicle which can solveenvironmental problems and energy crisis is the representative of new energy vehicles,with characteristics of battery is its power source and without internal combustion enginedetermines its power steering system need for electric power steering. In addition, thereare differences with battery electric vehicles and conventional fuel vehicles in the electricpower steering control system, etc.. Therefore, the study of battery electric vehicle withelectric power steering system has a great significance.It deeply studies on gear box and control system of the electric power steeringsystem. The specific research contents and main works are as follows:The first, through studying on the present reducing mechanism of electric powersteering system, it put forward that using field modulated magnetic gear as electric powersteering’s deceleration devices. Then it makes the theoretical analysis of the new devicesand designs the basic structure of the electric power system.The second, by analyzing control strategy and power characteristic of electric powersteering system, it eventually determines the control strategy of the basic power controlmode; furthermore, the power characteristic curve of electric power steering system usedon battery electric vehicles is realized by using fuzzy control strategy. The simulationresult shows the power characteristics control strategy based on fuzzy control is in linewith power requirements of a battery electric vehicle with electric power steering systemduring the actual steering.The third, through establishing the simulation model of electric power steeringsystem, it makes the simulation analysis on control strategy of the motor current.Simulation results show that the current controller has a high response speed and goodfollow nature to target current; it can satisfy the requirements of the actual steeringsystem.The last, it designs electronic control unit hardware programs and control system’s software flow of electric power steering system used on battery electric vehicles.