Designand Research Of Electric Power Steering System Of Carrier Vehicles

Compared with conventional power steering systems, electric power steering system (EPS) has a great advantage that it provides much more comfort and stabilization which makes it become a trend in the fast developing period of the automobile power steering. According to the special working condition, the EPS system of carrier vehicles need decide an adaptable assisting characteristic, so that drivers can obtain more comfortable feel of roads.In the macroscopical aspect of the EPS system of carrier vehicles, the article analyses its dynamics, and illuminates the three working modes based on its special working condition. Then an adaptable curve of assisting characteristic is particularly designed to match to the most frequent working mode of assisting. An simulating model of the EPS systems is so established in the environment of matlab/ simulink, and a usual process of steering is simulated and analysed by the model.The controller designed by the article combines the controller of the motor and that of the system. The whole structure of controller is introduced followed by the particular depiction of the keystones of hardware as well as software. A simulating model of brushless DC motor based on torque closed loop is established in the environment of matlab/ simulink. Setting a certain torque and a certain rotating speed, the model simulates a process that the motor provides assisting torque.The article researches on the brushless DC motor. The article analyses the cause of the existence of BLDC's cogging torque, recommends several methods to reduce it such as staggering or leaning magnetic poles, changing percentage of pole embrace and changing the cooperation of poles and slots, and compares these methods. Finally the performance of the motor is simulated and tested, which validates that the performance of the motor satisfies the need of the EPS system.