Research And Development Of The Automobile Electric Power Steering System Based ARM

Electric Power Steering System (EPS) is one of the research focuses of automotive engineering. Based on the study of the operation principles of EPS, the electric circuits and the software program of the electronic control unit of EPS was designed and developed, also the bed test was carried out.The electronic control unit based on ARMSys-C board (Samsung S3C44BOX) was designed, and the sampling of torque sensor,the sampling of Hall current sensor,the sampling of the vehicle speed and the sampling of the engine speed was carded out. The construction and the equivalent circuit of the DC motor used on EPS as weel as the key technique of Pulse Width Modulation(PWM) are introduced,then the concerned power loss is analyzed.The electric power steering system is devised based on these techniques. Furthermore, the protection and the heatsinking measure of the drive circuit is designed.The motor control strategy of the EPS system was discussed.Three types of motor control methods such as current control method,voltage control method,torque control method and their characteristics based on the equivalent circuit of the DC motor used on EPS are introduced. The motor was controlled acconding to the motor current control method.Relevant software program was developed in modular, that as the realizztion of the main program of the system,the A/D sampling program,the sampling of the vehicle speed and the engine speed,the figure-filter program,the PWM control program,the motor current compensation program and the fault diagnosis and display program.The test bed as weel as a quarter of vehicle model is designed and the experiments is introduced and analyzed. The results show that the motor current control method can be realized easily and the system devised is stable and credible, and can meet the requirements of steering performance.