Research On Integrated Control Of Lateral Stability Of Distributed Drive Electric Vehicle

The distributed drive electric vehicle has unique advantages of four wheel drive/ braking torque controlled independently.Therefore,the lateral stability control of distributed drive electric vehicle is studied in this paper.First,dynamic modeling of distributed drive electric vehicle is built by using MATLAB/Simulink software,and a linear two degree of freedom reference model is set up.Then,the grey prediction model is applied to preprocess the data.According to the degree of vehicle stability,the control domain is divided into non domain,extension domain and classical domain,and different control methods are applied in different control areas.Based on extension control theory,extension coordination controller is designed to coordinate the weight of yaw rate controller and side slip angle controller.The total driving torque and the additional yaw moment are optimized by the pseudo inverse optimization algorithm.Through different road friction coefficient under the condition of double lane change experiments to verify the effectiveness of the control strategy.Aiming at the conventional lateral stability control based on direct yaw moment,the four wheel drive/brake torque changes greatly,and the driving energy consumption is higher.Taking the driving efficiency of the hub motor into account,the conventional lateral stability control is improved,and the extension joint control strategy of minimum energy consumption and stability is proposed.The upper and middle layer controllers remain unchanged,and the lower layer controller is improved mainly.The lower layer controller is divided into three control modes: the stability control mode,the minimum energy consumption control mode and the extension joint control mode,and the different control modes are adopted in the different control domains according to the stability of the vehicle.The simulation results show that vehicle control strategy can effectively guarantee vehicle lateral stability and reduce vehicle energy consumption and increase mileage.Taking the active front wheel steering control into consideration,the extension joint control strategy of active front wheel steering(AFS)and direct yaw moment(DYC)based on phase plane method is proposed.The nonlinear two degree of freedom model is used to draw the β-β phase plane,and the boundary function of the stable domain is fitted with the change of the speed,the adhesion coefficient of the road and the turning angle of the front wheel.According to the phase plane method,the control domain is divided by fitting the boundary function of the stable domain to make it corresponding to the stability of the vehicle,and the weight of the AFS controller and DYC controller are calculated by using the correlation function.Finally,the simulation results proves the strategy not only improves vehicle stability but also does not interfere with driver operation.Finally,the hub motor experiment platform is designed and built,and motor model and motor efficiency map diagram based on experimental data are established.Based on the hub motor experiment platform,the hardware in the loop simulation experiment is carried out jointly with CarSim and LabVIEW,and the vehicle control strategy is verified.The prototype platform of rear wheel hub motor is designed and retrofitted,and the real vehicle experiment is carried out,which laid the foundation for the next driving energy consumption control experiment.