Modeling And Simulating Research Of The Electric Power Steering System Control Performance

The development of the steering system has experienced several phases from the simple Mechanical Steering System, Hydraulic Power Steering System, Electric-Hydraulic Steering System, till the Electric Power Steering System (EPS) which has even lower energy consumption and higher performance. The EPS uses electric motor to assist power, is applied more and more widely in automobile industry, which is led by its advantages over the traditional hydraulic power steering system in safety, environmental protection, engine efficiency, and easiness on the adjustment. It is a hot topic and has the trend to replace the Hydraulic Power Steering.At first, based on the analysis the configuration types, work principle and the main parts characteristic of the EPS, the paper has predigested the EPS dynamic model, established state space description. Combined with the dynamic model of the system, it has analyzed the system steady state performance and the assist power characteristic. Based on the paper the key parts such as sensors and electric motor has been selected.Control strategy would touch the EPS's performance, the paper analyzed the assist power control strategy, the return ability control strategy and damp control strategy based on summarizing the control aim, and it confirmed implement occasion about the control mode. It also introduced the basic control performance of EPS such as the turning handiness performance, the steering stability, the economy of fuel, the return back capability and the security of the system etc. The paper has discussed the question for confirming and following aim current of the assist engine. For getting the accurate assist characteristic graph, it used FNN controller to confirm the aim current; For restraining the interferer, it built H_∞controller separately to contrast the effect of the following current.In the environment of MATLAB/SIMULINK, it has built system model used the simulink tools in order to test the contents of the analysis, and separately emulated and analyzed the run occasion and control power magnitude of the assist power control strategy, the return ability control strategy and damp control strategy, especially for the assist power characteristic curve, accelerate return ability performance and damp control effect. And to validate the performance of following aim current, it used H_∞controller to control the electric motor model. At last, a design model of EPS test-bed was built, which provided academic basis for further research on EPS experiment. It has discussed the function and request of EPS test-bed, selected mechanism parts and controller hardware. Then it has confirmed the experimentation project using the test-bed, which provided academic basis for further research.