Research On Control Strategy For Vehicle EPS System And Scheme Design For EPS Test-bed

The vehicle steering system is a critical component to the handling stability, initiative security and comfort of the vehicle. With the development of vehicle electronics and the increasing demand for more safety and better comfort, EPS (Electric Power Steering) has become the research focus of the power steering technology. EPS has advantages of energy saving, safe, comfort, easy maintenance and good for environment protection, which traditional Hydraulic power steering system can not reach, so EPS becomes the development trend of power steering technology in the future.Took EPS as research objective, this paper established two-dimensional vehicle dynamic model and steering system dynamic model. On the basis of that, a detailed analysis of assist characteristics of EPS was made. Then, this paper put forward a method to evaluate the performance of EPS in three aspects:motor current following performance, yaw rate transient response and steering feel. After that, PID and adaptive fuzzy PID method were designed to control the motor. Simulation results showed that adaptive fuzzy PID control strategy inhibited system uncertainties and external disturbances effectively which optimized motor current follow performance and meet the requirements of EPS on steering agility and steering feel.This paper proposed a preliminary design for the EPS test bench. The main functions of the test bench were simulation of the steering resistance load, acquisition and processing of test data, as well as analysis and evaluation of EPS performance. This paper designed data acquisition system for the test bench based on MC9SDG128 microprocessor and achieved signal acquisition. of steering wheel torque, motor current and voltage. What's more, a friendly human-machine interface, easy data acquisition and stable measures of control software was developed based on LabVIEW platform.