Research On Control Strategy And Implementation Of Controller Of EPS System

Electric power steering (hereinafter referred to as EPS) can meet the three requirements of modern vehicles, which are safety, energy conservation, and environmental protection, and represent the research direction and the development goals of the automotive steering system. EPS has been successfully applied to many automotive models abroad, while still in stage of research and development at home. In recent years, EPS has been the research hot spot with broad application prospects in domestic automobile steering.EPS control system is an important part in EPS and a significant influence on handy and stable steering. EPS system is a complicated system with nonlinearity, multi-input and multi-output, thus good control effects are difficult to obtain through classic control algorithm. Based on the improvement of Radial Basis Function Neural Network, the dynamical characteristics surface has been studied, the continuous current dynamo controlled through Fuzzy PID control technology, and the hardware and software of the controller designed and realized.Firstly, the operating principles and the structural characteristics are introduced, and structures and operating principles of key components were discussed in detail.Secondly, the control strategies of the EPS system were studied. Control modes and dynamical characteristics surface were analyzed, improvements of the RBF neural network and its applications to the dynamical characteristics surface discussed in detail, fuzzy PID controller designed, and comparisons with other control technologies are analyzed using MATLAB simulations.Thirdly, the electronic control unit of the EPS system was designed. Microchip PIC18F4431as the core of the control unit, C-language as the design language, hardware and software of the ECU were designed and developed, and the communication with the PC testing interface was designed with Lab VIEW.Finally, experiments were carried out. Based on the requirements and basic expected functions of the EPS system experiment platform, the structure was designed, the sensors and the actuators for the mechanical structure and the controlling parts were chosen, and the experiment testing platform was built. Experiments were carried on the experiment platform; the proposed control strategies and ECU controller were tested; and the results meet the design requirements, which lay solid foundation for the future research.