Study On Vehicle Electric Power Steering System

Along with the economic, environmental, active safety of Automobile the growing importance of low-emission vehicles (LEV),hybrid electric vehicle (HEV),the fuel cell vehicle (powered electric),Electric Vehicle (EV) four "EV" the rapid development of automobile, electronic technology and following the engine, transmission, brake and suspension systems to be widely used, Foreign car EPS (listed EPS) is gradually replacing the traditional hydraulic power steering (listed HPS)The EPS (Electric Power Steering) system is an power steering system whose assist torque is provided by the motor directly .The assist torque is controlled by ECU. EPS can improve vehicle active safety , save energy, benefit the environment,and is easy to be modularized . It is a new high-tech which follows modern automobile development topic closely. The EPS technology becomes gradually consummate and is going to replace HPS(Hydraulic Power Steering). It is one of the future development directions of power steering .Electric power steering system controller and its actual implementation process is targeting current and target tracking current process, Power characteristics can be divided into the identification and control of the current target of two phases. In the course of the issue, mainly on the work must include : right to the target vehicle characteristics; Steering wheel torque characteristics ideal; electric power steering system 40,000 properties; the motor torque characteristics of the study; Current goals of the tracking control strategy.In modeling and simulation studies, the establishment of a seven-DOF vehicle model, electric power steering system model Steady and vertical tire cornering joint condition model, the right to resistance, be a vehicle without power steering resistance moment. And the simulation results and the actual results of the test vehicles, verification of the model accuracy and applicabilityAnalysis of the three different forms of EPS power characteristics, and the final use of linear power characteristics, Power characteristics based on the requirements of simulation, the total assistance without resistance Moment, Steering wheel torque to ideal values to importation as identified in help torque, which reached nearly two distribution relationship, Power characteristics with the slope values. For different speed, and because of their resistance to swerve ideal moment occurred change, Power characteristics of the corresponding value of the slope of subsequent changes, the simulation speed up the corresponding slope. Information will be added to speed EPS power characteristics. Ideal Steering wheel torque is relatively abstract and subjective feelings on the issue. Based on several different ideals Steering wheel torque value of the analysis, initially set up in China for a group of pilots ideal moment, and the basis for the use of sub-linear characteristic curve parameters help define. Determine the outcome of the basic balance of a low-speed light of the requirements of high speed and under the correct path flu requirements.For current control strategy adopted more modern application of the PID control method from the current simulation results, control the results have been satisfactory. From the controller production, easy to implement, low cost and speed of response to completely meet the requirements. For assistance characteristics and the overall control strategy certification, Power characteristics will join with motor mechanical structure model electric power steering system model, Current control strategies will be used in electric motor model, In accordance with the motor torque characteristics of torque characteristic forms of assistance into current forms of assistance characteristics, Simulation of the current goal of control. Simulation results show that the fundamental shift does not affect low-speed light of thecircumstances, the high-speed road that flu has been noticeably improved.DSPACE generated using rapid prototyping, hardware-in-the-loop testing, verification of the control strategy with the goal of current sexual.In conclusion the content of the paper and conclusions, and deals with the study made a number of recommendations.