Simulation Research On The Control Of Electronic Differential System Of Dual-motor Rear-drive Electric Vehicle

In response to the emergence of distributed motor drive technology in the automotive field,electronic differential control systems have become an important research aspect of electric vehicle technology development.Single-motor-driven electric vehicles and traditional fuel vehicles usually need to be equipped with a mechanical differential,and their dynamics-related performance is very limited,and it is difficult for vehicles to maintain the original handling stability under more complicated road conditions.However,for distributed electric vehicles,if the electronic differential system is properly controlled,not only the traditional mechanical differential is omitted,but also the dynamics of the vehicle can be improved,so this paper mainly develops the design of the electronic differential control system Work with validation research.In the study of the electronic differential control strategy,in order to ensure the accuracy of the upper control input parameters as much as possible and reflect the non-linear motion state of the car,a seven-degree-of-freedom vehicle dynamics model including longitudinal,lateral,yaw and four wheels is established.Because the deformation and slipping of the wheel will affect the force between the ground and the wheel,the "magic formula" tire model is used to reflect the change in tire force during actual driving.At present,permanent magnet synchronous motors are widely used in electric vehicles,which have the advantages of low electromagnetic losses and easy implementation of weak field control.Therefore,we chose to use permanent magnet synchronous motors as the research object to drive motors.In this paper,the designed electronic differential control strategy includes upper control and lower control.Among them,the upper control includes:(1)The torque distribution control strategy based on fuzzy control uses the mass center slip angle and the yaw angular velocity in the vehicle yaw motion parameters as the control input,and the additional yaw moment can be obtained.(2)The slip rate control strategy based on sliding mode variable structure control determines the definition function of the slip mode surface from the vehicle slip rate deviation,and then obtains the actual equivalent driving torque,which is regarded as additional torque.In the study of the bottom-level joint optimization control strategy,after analyzing the limitations of the current control strategy in practical applications,considering the driving torque limit conditions in the actual driving process,two new types of bottom-level control schemes were designed.The front wheel angle and steering angle speed and the slip rate is a control parameter to adapt to the driving requirements under different road conditions.The serpentine road conditions and the double shift line road conditions are selected,and the ideal driving motion parameters of the car are analyzed through simulation research,and compared with simulation verification.This paper uses carsim and simulink joint simulation platform to build a seven-degree-of-freedom vehicle model,a "magic formula" tire model,and a permanent magnet synchronous motor model.The torque distribution control strategy based on fuzzy control and the slip rate control strategy based on sliding mode control are simulated separately,and then the upper layer control strategy is combined with the bottom layer joint optimization control to carry out collaborative control to improve the vehicle handling stability.