Research On Integrated Control Of Vehicle Semi-active Suspension And Electric Power Steering System

At present,the single-system control technology of semi-active suspension and electric power steering system is relatively mature.To further improve the overall performance of the vehicle,it is particularly important to integrate control of semi-active suspension and electric power steering system.Therefore,this paper designs an integrated controller by analyzing the relationship between the semi-active suspension and the electric power steering system.The integrated controller is used to control the integrated model of semi-active suspension and electric power steering system,and the theoretical analysis and simulation research are performed.In order to improve the ride comfort and handling stability of the vehicle,this paper studies the integrated control of semi-active suspension and electric power steering.The main research work has the following aspects:(1)Establish 1/4 semi-active suspension system,electric power steering system,road surface,tires,and integrated vehicle dynamics models of semi-active suspension and electric power steering system.Considering the roll motion conditions,pitch motion conditions,vertical motion conditions and steering motion conditions of the integrated system,and the state equations are established,and the state equation coefficient matrix is given to provide a basis for the subsequent simulation.(2)In AMESim software,a 1/4 passive suspension physical model is built,and a semi-active suspension model is built on the basis of the passive suspension.The suspension fuzzy controller is designed in MATLAB / Simulink software,and joint simulation is performed by AMESim and MATLAB / Simulink software to verify the effectiveness of the suspension fuzzy controller.(3)Build an EPS model in AMESim software,and design the help characteristic curve.Design the EPSPID controller in MATLAB / Simulink software.The joint simulation was carried out by AMESim and MATLAB / Simulink software to verify the effectiveness of the assist characteristic curve and PID controller.(4)Establish an integrated controller for semi-active suspension and electric power steering.This integrated controller includes an upper-level coordination controller and a lower-level subsystem controller.The lower-level subsystem controller includes a suspension fuzzy controller,a cornering fuzzy controller,a suspension force distributor,and an EPSPID controller.According to the integrated vehicle dynamics model,a passive vehicle model was built in the AMESim software.Based on the passive model of the whole vehicle,an integrated control model is built in MATLAB software.Finally,the simulation of the semi-active suspension and electric power steering system and the integrated control model built by AMESim and MATLAB / Simulink software is performed.The simulation results show that the integrated control of the vehicle's semi-active suspension and electric power steering system can effectively reduce performance indicators such as vehicle body vertical acceleration,suspension dynamic travel,body roll angle,body pitch angle,and body roll angle acceleration,and improve performance indicators.It improves the ride comfort and handling stability of the vehicle.