Digital Control And Research Of Electro-Hydraulic Power Steering System

Electro-Hydraulic Power Steering system, compared with traditional hydraulic steering system, has more advantages, such as saving energy, making driving easy, and so on. It is the necessary step in developing automobile steering system. The thesis, on the base of using advanced theories in the field, studies the Electro-Hydraulic Power Steering system, and develops the relative software. Finally, making the excellent digital EHPS come true.In the project, the structure and principle of the Electro-Hydraulic Power Steering system are analyzed and BP nerve network is used to simulate its curve. The Brushless DC Motor, important part of the system is well controlled including two-closed-loop control method, compensation for dead-time and analysis of fluctuation about swapping phases. At last, the PID parameters were confirmed by using the method of intelligence control --Applied Genetic Algorithm and the curve is simulated in MATLAB.Based on the Motorola provides the strong design platform and SDK, the EHPS system software is developed. The controlling system uses the parameters of steering speed and the vehicle speed, which have the connection of the steering power, so the real time character is improved. The advanced Algorithm and the excellent motor control contribute to the good performance of the EHPS system. The results of the testing curve prove this point.The data acquisition, analysis, and inspection of the EHPS system are completed by LabVIEW and MATLAB. The article provides three methods including MATLAB, LabVIEW and programming together to collect and analyze the testing data. The function of graph display of LabVIEW can inspect the system perfectly. The real time inspection is improved, and more information, which displays the system working condition, is provided exactly by using LabVIEW.The three buses of the vehicle are CAN BUS, LIN BUS and MOST BUS. The CAN BUS has advantages such as fast transmission speed, good anti-interference ability, and reliability, so it is often used in the communication network of the automobile. Through connecting two ECUs by CAN bus, which is the smallest CAN network, and finishing dates transmission, the function of communication is reached. Finally, the testing curve is draw by LabVIEW, and the results prove that the system is available; also, the expecting requirements are achieved.