Research And Development Of Control Strategy Of The Electric Power Steering System For Car

With the development of economy and the sinence technology, people put more and more attention to the performance of automobile steering system, people also put forward higher requirements on it. The performance of automobile steering system affects the driving safety and handling stability of the automobile.Compared with pure mechanical Steering system, Electric Power Steering system(EPS) solved the problem of the Steering portability. Electric Power Steering system provided the appropriate power to assist steering according to different working conditions, the power characteristic is variable. It can improves the steering portability, steering stability, driving comfort and the safety. The Electric Power Steering(EPS) system has been more and more get the favour of people and very suitable for assembly on the car because of its the advantages of energy-saving, environmental protection, adjustable assist characteristics, simple assembly, and small space. Therefore, the EPS system has great application field and market development space. At present, the EPS system in China is still in the growth stage, most of the core technology by foreign monopoly, the control strategy and reliability of the controller needs to be improved. Therefore, this article has carried on the research and test of control stategy development for EPS system.Using multi-body dynamics theory to established in CarSim software includes vehicle transmission, braking systems, steering systems, suspension systems, tires and bodywork of the vehicle model. On the vehicle model for simulation analysis, some shortcomings in terms of steering through contrast were found. By studying the structure and work principle of EPS system, the parameters and structure of the key components are matched, which consists of assist motor,torque sensor, electromagnetic clutch and electronic control unit,etc. The overall control strategy of EPS system is designed, the power of the motor torque control and control strategy is also studied. And the analysis and calculation on the dynamical characteristics parameters. The simulation model of EPS system based on Matlab/Simulink is built, which consists of mechanical steering system model, motor model and controller model, etc. The EPS is on the basis of an in-depth study with CarSim software vehicle dynamic model, and establish EPS control system model in MATLAB software. Car Sim is combined with the MATLAB, electric power steering system with a combination of vehicle models and aco- simulation study to verify the effectiveness about the control strategy. The simulation results show that the control strategy improved the steering portability of the automobile.