The Research On The Control Method And Performance Simulation Of Electric Power Steering System

As a new technology of automotive power steering, Electric power steeringsystem (EPS) acts more important effect in the field of the maneuverability, thecomfortableness and the security for the automobile. EPS can not only ensure steeringhandiness at lower velocity and handling stability at high speeds, but also promotemodern automobile technology marked by energy efficiency,environmental protection,safety and comfort.With the rapid development and wide application of electronictechnology, EPS makes a rapid advancement and the good market application prospect,so that more and more attention is being paid to EPS by lots of research constructionsand famous manufacturers in the word.Focusing on the issues of EPS’s performance control, in this thesis, a completemodel of the steering system including the mathematical model, the mechatronicmodel and control models was established based on Carsim and MATLAB/Si mulinksoftware. Experimental results conducted based on visual simulation platform showthe effectiveness of the simulation model and control strategy.Firstly, the Thesis gives a review on research background and the significance,the history and prospect of EPS. And then the paper pointes out the key technologyand the present application around the world. The article expounds the application ofvisual simulation technology in vehicle design and development and discusses thecomposition, working principle, arrangement and modeling method. A simulation testplatform was built up on the basis of Carsim and Simulink. In MATLAB/Simulink,EPS simulation model is composed of steering wheel model, steering systemmodel,tire resistance model and assisted motor model through dynamic equation. InCarsim, parameters of automobile were set to establish a dynamics model forcomplete vehicle.Secondly, given the EPS performance evaluation, a control strategy and modecontroller is designed based on the former research achievement in order to realize thetarget of control under multiple working conditions and road conditions. Taking thelinear assist characteristics after a comparative study of three types of assistcharacteristic. The PID fuzzy controller was applied to confirm current required. Anadaptive sliding mode controller is designed to adjust the alignment torque. Damping control is proposed to decrease interference of torque ripple. Compensation controlis used to improve dynamic tracking performance of system.Thirdly,considering the importance of return, in the return control strategy, asliding mode controller based on ideal reference returning model is set up to help thevehicle to achieve a good performance of return and provide the driver’s road feelingat low vehicle speed or high speed. The return controller can determinate the statewhether the vehicle is steering or returning.Finally, a virtual driving environment is created based on the co-simulationplatform developed through Carsim and MATLAB/Simulink. The results of simulationprove that the vehicle model equipped with the EPS can realize the ideal steering forthe drive and improve the handing characteristics. The end of this paper is summerythat points out the problem to be improved and indicates the direction of the work inthe future.