Yaw Stability Control For Networked Electric Vehicle Based On Observer

With the continuous improvement of per capita gross national income,China's automobile industry has also been developing rapidly.While cars bring great convenience to People's Daily life,they are accompanied by many problems.New energy electric vehicles have gradually received widespread attention because of the dual problems of environmental pollution and lack of energy.In addition,along with the continuous maturity of electronic control unit technology,networked control is widely used in vehicle control.However,networked control will inevitably lead to problems such as data packet loss and transmission delay,which will have a serious impact on the driving safety of networked electric vehicles.In this paper,the yaw stability control of networked electric vehicles is studied.Firstly,based on the theory of vehicle dynamics and kinematics,the mathematical model of networked electric vehicle is established,which includes seven degree of freedom and two degree of freedom vehicle model,wheel model,tire model,hub motor model,driver model and so on.The accuracy of the model is verified by Carsim/simulink joint simulation.Secondly,speed estimator based on acceleration sensor,Extended Kalman Filter based on side dynamic response and Unknown Input Observer(UIO)based on high order and high gain sliding mode differentiator are designed to estimate the speed,road adhesion coefficient and side slip angle of networked electric vehicles.The simulation with MATLAB/simulink proves the validity of the proposed estimation method.After that,the discrete model of networked control ev is established,the causes of network time delay and its influence on vehicle stability control are analyzed,and the simulation results are verified.The simulation results show that networked time delay can cause great oscillation of vehicle yaw velocity,side slip angle and output torque of hub motor.Finally,a control strategy based on dynamic efficiency matrix allocation algorithm is proposed.The influence of yaw velocity and centroid Angle on vehicle stability is analyzed,and the criterion based on d ?-? phase plane stability region is established.Firstly,the control algorithm introduces a three-parameter friction ellipse fitting function to express the tire force coupling characteristics under critical conditions.Then a local linearization method is applied to represent the relation of longitudinal and lateral forces.The linear gradient is obtained by solving the friction ellipse function.Finally,the dynamic efficiency matrix is produced with real-time variables,and the quadratic programming based on weighted least squares(WLS)is designed to realize torque allocation.Carsim/simulink cosimulation was used to verify the effectiveness of the proposed scheme.