Research On Stability Control Of Steered By Wire Vehicles Based On Vehicle State Parameter Estimation

With the gradual development of electronic technology and control algorithm,the control of automobile steering system is becoming more and more unmanned and intelligent.As a key technology to realize unmanned driving,Steer-by-Wire(SBW)technology needs more systematic and comprehensive research to improve its control performance and anti-interference ability.The paper takes the steer-by-wire vehicle as the main research object.Considering that the vehicle may have steering instability due to road surface changes and control deviations during steering,the acquisition method of vehicle driving parameters is improved and the corresponding stability comprehensive control strategy is designed.In this paper,the dynamic analysis of the steering actuator is carried out,and the Permanent Magnetic Synchronous Machine(PMSM)is selected as the steering actuator motor.Based on the dynamic theory,the vehicle model of the steer-by-wire system is built.The effectiveness of the steer-by-wire vehicle model is verified by co-simulation.A three-degree-of-freedom vehicle model and a magic formula tire model are built.The Unscented Kalman Filter(UKF)algorithm suitable for nonlinear systems is selected for vehicle state parameter estimation.The shortcomings of the parameter estimation method are summarized and analyzed through theory and experiment,and the corresponding improved method is used to design an adaptive unscented Kalman filter algorithm with adaptive observation noise,anti-interference and low error characteristics for vehicle state parameter acquisition.The linear two-degree-of-freedom vehicle model is built,and the ideal value of the vehicle state parameters is obtained by analyzing the vehicle stability state.The adaptive reaching law sliding mode control method is introduced to solve the sliding mode additional front wheel angle for yaw rate and sideslip angle respectively.The extension sliding mode control method is used to adjust the output of the additional front wheel angle in different control domains to obtain the extension sliding mode additional front wheel angle.The phase plane control method is selected to determine the stability state of the vehicle,and the extension sliding mode additional front wheel angle corresponding to each parameter is weighted to obtain the final required additional front wheel angle.A Multi-Loop Adaptive Fuzzy Control(MLAFC)method is proposed for steering motor control to track the target front wheel angle.Through the above theoretical analysis,the corresponding control modules under each control method are built and the parameters are given,and the joint simulation verification is carried out under multiple working conditions.The results show that the stability comprehensive control strategy designed in this paper improves the control effect of vehicle driving stability,angle tracking control accuracy and response,and can effectively improve the vehicle ’s handling performance and reduce the driver’s burden.