Research On Road Feel Control And Stability Of Steer-by-Wire System

Steering systems are critical to the safety of the car and are closely related to driving comfort,so major car manufacturers and research institutes have never stopped researching automotive steering systems.As the recognized trend of the next generation of automotive steering systems,steer-by-wire steering has the advantage that traditional steering systems are difficult to match in improving vehicle handling stability and driving safety.Since stability is an important structural property of the system,system dynamics stability is an important prerequisite for putting it into engineering applications.And the SBW system usually generates road feeling through road-sensing motor simulation.Therefore,the advantages and disadvantages of the road-sensing simulation strategy design are also crucial for the wire-controlled steering system.This paper focuses on the following research work around the line-controlled steering sense control system and its stability.This paper first briefly describes the relevant structural components,key technologies and reliability of the steer-by-wire system.Based on this,the working principle of the line-controlled steering system is analyzed,and the SBW system is simplified and modeled according to the reduced-order modeling idea.Then the dynamic behavior of the model is analyzed by the theory of dynamic system stability.The stability conditions of the zero solution of the SBW system dynamics model are studied,and the structural parameters of a set of systems are obtained.The vehicle model of SBW system was constructed by CarSim,and the influence of the motor speed reduction ratio of the key parameters of the SBW system and the motor moment of inertia on the steering stability of the vehicle was studied.The results show that the SBW system parameters have a significant impact on the vehicle handling stability,and the vehicle handling stability can be improved by changing the SBW system parameters.Secondly,the SBW system road sensation simulation control strategy is studied.Based on the traditional steering system road model,the road model motor model and the steering wheel torque mathematical model are analyzed,and the road-sensing simulation mathematical model of the line-controlled steering system is established.Three kinds of road-sensing simulation algorithms,such as PID,fuzzy PID and fuzzy immune PID,are designed,and the designed algorithm is used to verify the designed algorithm by Matlab/Simulink using sine and step as input signals.The results show that the designed algorithm has better tracking effect on target torque under different types of signal input,and can be used for line-controlled steering path simulation.Finally,verify the impact of the designed control strategy on vehicle handling stability and driving comfort.Based on the analysis of the relationship between road sensation acquisition and influencing factors,the related evaluation indicators of road sensation are summarized.Subsequently,the designed strategy is applied to the established vehicle model,and the serpentine and double-shifting conditions are selected to verify the ability of the remotely controlled vehicle model with the designed road-sensing strategy to maintain stable driving after being disturbed;The central area and the double-line working condition were selected to verify the accuracy of the vehicle model in the high-speed driving road sense and the steering portability in low-speed driving.The results show that the designed road-sensing simulation strategy has strong anti-interference and solves the problems of “light” and “spirit” in the traditional steering system.