Research On Vehicle Virtual Prototype Design And Control Strategy Based On Active Suspension System

The suspension system is one of the most important components of the vehicle.It is the sum of all the force transmission devices between the vehicle body and the tire.It is used to buffer and absorb the vibration from the wheel and to transmit the driving force and braking force of the road surface.The performance of the vehicle suspension is closely related to the handling performance of the car and the comfort level of the occupants.The traditional passive suspension is constrained by its structural form,and its performance has been difficult to improve.The active suspension system relies on a controllable force triggering mechanism,which can automatically adjust according to the road surface conditions and obtain excellent performance,which has become a research hotspot in recent years.In recent years,the development of sensors and computer technology has also provided support for the implementation of active suspension systems.However,the factors considered in the suspension system modeling method commonly used in the research community are not perfect.The establishment of many control strategies also ignores the actual characteristics of the vehicle's strong nonlinearity and internal and external disturbances.Thus,the research towards suspension virtual prototype and control algorithm is of great theoretical and engineering value.This paper carries out design research with the vehicle suspension system as the object.Based on the analysis and research of the quarter-car and semi-vehicle models,this paper establishes a seven-degree-of-freedom nonlinear vehicle suspension mathematical model,and builds a full-vehicle virtual prototype based on ADAMS software,which is compared with the mathematical model.And verification,and finally proposed the anti-disturbance control based on fuzzy sliding mode to achieve the improvement of ride comfort and operational stability.The main research contents are as follows:1)Design of mathematical models for vehicle suspension systems and road input.Based on the analysis of the two-degree-of-freedom quarter car and the four-degree-of-freedom semi-vehicle model,a seven-degree-of-freedom vehicle model considering the nonlinear characteristics of the spring damper is established.Through the frequency domain and time domain analysis of the road surface input,the random road input model is established,and the performance evaluation index of the suspension system is given.2)Establishment of a virtual prototype of the vehicle suspension system.The suspension mathematical model is a simplified vibration model that ignores the physical structure of the suspension system during the build process.The dynamic simulation software ADAMS is used to establish the virtual prototype of the vehicle suspension system,and their characteristics are compared.The results show that the two are similar in motion amplitude and trend.The motion amplitude and vibration frequency of the virtual prototype are smaller than the mathematical model.The parameter correction can make the two outputs consistent.3)Controller design of the suspension system.Based on the idea of skyhook control,a reference model is proposed and its vehicle model is established.After the coupling analysis and decoupling of the system,the linear auto-disturbance suppression controller(ADRC)is designed to control the suspension system for the strong nonlinearity of the vehicle suspension system and the difficulty of obtaining accurate models.The system is disturbed and unbuilt.The mode dynamics are attributed to "overall disturbances",which are observed using an extended state observer(ESO)and compensated for in the state error feedback(SEF)law.In order to improve the tracking characteristics of the controller and enhance its robustness,it is proposed to improve by using sliding mode control,and use fuzzy theory to suppress the inherent "vibration" problem of sliding mode control,which constitutes the active disturbance rejection control based on fuzzy sliding mode(FSM-ADRC).4)Co-simulation analysis of the suspension system.Through the joint simulation of ADAMS and MATLAB/Simulink,the control performance of ADRC,SM-ADRC and FSM-ADRC on the virtual prototype of the vehicle is compared under random road input.The performance of the controller under the variation of system parameters is verified,which validates the effectiveness of the control strategy.