Research On Model Analysis And Handling Perforance Of Electric Power Steering System For Vehicle

EPS(Electric Power Steering)is a new type of automobile steering system developed recently, which has the advantages of saving fuel,reducing overall weight, easier installation and maintenance, improving driving security and producing less pollutions.EPS is taking the place of HPS (Hydraulic Power Steering) gradually and becoming one of the hotspot in the research of automobile technology in the world. A lot of external famous automobile companies have adopted this kind of steering system and it is necessary for automobile industry of our country to master this high-technology as soon as possible.Therefore, it is of great importance to study and develop this kind of steering system.Firstly, two possible EPS reducing transmission agencies have been processed by kinematic and dynamic analysis, summing up the two reducing transmission institutions of the respective advantages and disadvantages. Then , the type of motor is determined by EPS system parameters, and the worm gear,differential gear train and steering shaft parameters are determined by mechanical and automotive design theory, also using library functions optimizes worm gear parameters, which also can be considered as the important parameters in modeling.Secondly, outlining the trapezoid body's component and role, designing the whole trapezoid body and determining the distributive trapezoid body parameters according to the traditional automobile design and trapezoid body design. Meanwhile, elaborating the relationship between stress and operation stability, analyzing the stable state response and frequency response about attribute automobile, based on these, it carries on examples analysis of Buick and Ferrari's parameters, the variation of sway angular speed frequency can be drawn by MATLAB under the two sections car with no speed. For more directly determination the different parameters steering characteristics, developing and installing the EPS system automobile's operation stability analyses platform with GUI in MATLAB.Analyzing EPS servo-link's extant straight line, the broken line and the curve three kinds of assisting curve respective good and bad points, basing on the research at present situation determination based on worm gear worm—differential gear train transmission system when EPS system's straight line assisting characteristic curve each parameter, then, the consult material assigns a group of steering wheel moment of force along with several fixed vehicle speed value change data. The determination helps the moment of force graph based on this steering system's straight line ideal steering wheel torque and the electrical machinery , and using the data fitting law determination vehicle speed inductance, this curve's determination for following studies the EPS systems control electric circuit's establishment to lay the foundation .At last, in the differential gear train and the sectional trapezoidal organization and on the parameter definite foundations, establishing the independent worm gear worm bearing adjuster and the worm gear—differential gear train reduction gear organization steering system three-dimensional model separately. Simulation analysis of steering wheel when give a step-input, whether there is to assist in two kinds of situations rack's displacement, the velocity curve as well as the wheel corner change curve.To sum up, through analysis of the above-mentioned study compares worm gear -differential gear system to worm gear EPS system which has been applied in foreign country gains worm gear -differential gear system's advantages, reveals EPS based on transmission system's superiority by simulation model, propose a new opinion with studying and developing for the EPS system.