Modeling and characteristic curves of electric power steering system

Electric Power Steering (EPS) has important significance in improving the auto's dynamic and static performances. This paper deals with the mathematical model and characteristic curves of EPS System. First, the principle and structure of EPS are discussed. Then the characteristics of EPS system are analyzed, including the typical power curves which deal the relationship of the assist torque and the steering wheel torque. At last the EPS system's dynamic model and the computerized simulation model have been established in MATLAB/Simulink in teams of three aspects which are the mechanical steering without power system, EPS system and EPS system with PID control. The simulation result that the actual current of the motor follows precisely the target current validates the designed assist characteristic.