Automobile Electric Power Steering Control Strategy Research And Joint Simulation Analysis

As an important component of car, the performance of steering system directlyaffects vehicle’s handling stability, driving safety and ride comfort. Electric powersteering system (EPS) is a new type of steering system developed recently.With itsenergy saving, environmental protection, simple structure, good portability, real-timeadjustable assist force, good road feel and many other advantages, EPS is taking theplace of HPS gradually and becoming one of the hotspots in the research of automobiletechnology in the world.This paper firstly introduces the structure, working principle, main types,advantages as well as the current development of EPS. Based on the theory ofMulti-Body system dynamics, the whole vehicle model is built by ADAMS,whichincludes the front and rear suspension, steering system, tires, powertrain,brake systemand road files.And many files would be used in the simulation are written.Secondly, the ideal form and basic parameters of EPS assist characteristic isstudied and the method to built assist characteristic was analyzed. Combined with thevirtual prototype, a type of assist characteristic is realized by MATLAB/Simulink.Thirdly, the control strategy of EPS is analyzed, due to most of the parameters ofEPS are nonlinear and time-varying, this paper presents the fuzzy self-adjusting PIDcontrol strategy which combines the quickly dynamic response of fuzzy control and theadvantages of high precision of PID control.And then EPS control system is set up inthe MATLAB/Simulink, and combined with assist characteristic model, motor modeland PWM model, the whole EPS system is finally established.Finally, co-simulation technology is used to link the control model established inMATLAB/Simulink to the mechanical model established in ADAMS/Car, and a seriesof dynamic simulation test and analysis are carryed out by fuzzy self-adjusting PIDcontrol, the results verify the correctness of the model. And then, the influence of thecontrol strategy to handling stability is analyzed. The co-simulation results show thatco-simulation is effective and it could be applied in vehicle engineering.