Study On Control Method Of The Electric Power Steering System

Electric power steering system (EPS) is the development direction of automotive power steering, the system is based on the sensor by the electronic control unit to control the signals collected, so that power steering can be realized. EPS besides has the light steering torque like hydraulic power steering (HPS) system, its still has other characteristics such as steering placidly, environment protecting, low energy consuming and so on. At present, the research of the domestic EPS is behindhand, Therefore it is very important in practical significance in research of the EPS.The paper is based on deep research to the electric power steering system, take Matlab for the main simulation and researching tool. The thoroughly simulation and research have been made about the road feel and motor current of the electric power steering system.At first, the research significance of EPS, the development prospects, the main types and the working principle have been introduced, the present development of the domestic and foreign control policy of EPS is elaborated. Aiming at some questions exist in the current control policy research, the research content of the paper has been established.Secondly, by the depth study of the EPS system, the mathematical model of the EPS is established. Aiming at the operation stability, the simulation subsystem models are built.Then we study the load characteristics of the steering system, the vehicle state and road surface information are analysis, regard intensity of steering feeling as a performance index of appraising control system and set up the equation of intensity of steering feeling. Design a fuzzy immune PID controller for the EPS road feel control system, simulation results show that the control method is better than the traditional PID controller. Finally, the characteristic of the power steering and the motor current control method are researched. A simulation model of EPS is established, the T-S fuzzy control theory is briefly described, based on T-S model fuzzy neural network controller learning algorithm is analyzed. Based on T-S model fuzzy neural network of motor current controller is designed, thus ensuring the output current of the motor has a good tracking performance.