A Study On The Performance Simulation Of Steering Stability For Four Wheel Side Mottor Electric Vehicle

Nowadays,road traffic,environmental pollution and energy problems are worldwide problems.However,the problems that traditional internal combustion engine vehicles have highlighted in petroleum consumption and environmental pollution are becoming increasingly serious,especially in the north of our country in winter.Electric vehicles are attracting more and more attentions due to many features such as diversified energy use,high efficiency,environmental protection and performance.Traditional four-wheel steering is developed on the basis of diesel locomotive because of the low speed flexibility and high-speed stability of the conventional front-wheel steering vehicle,compared with that of the four-wheel steering vehicle.The vehicle weight is heavy,the cost is high,Speed matching is carried out under mechanical conditions.In this paper,the purpose of improving steering stability during cornering is to study the wheel steering and wheel torque distribution.First of all,according to the force situation during the vehicle driving,a two-degree-of-freedom vehicle dynamic model and a seven-degree-of-freedom four-wheel steering dynamics model are established.Analysis of the tire facing the force,the establishment of tire dynamics model.According to the car body model,the geometric equation of each wheel corner is established,which is the theoretical basis of the car steering and the corresponding simulation module is established in Simulink.Then,the factors influencing the handling stability of the vehicle during turning are analyzed,including the slip rate,lateral force,longitudinal force,center of mass roll angle and yaw rate,and the establishment of the front wheel steering control mode and the four wheel steering Control mode,and on the basis of its comparative analysis,low speed,poor mobility;low speed stability,and put forward to solve the control program.Finally,the technical innovation point of this paper is put forward:In the process of vehicle driving,according to different input steering angle and speed of the steering wheel,the wheels are deflected around the instantaneous steering center at different angles and then fed back to the steering input wheel to complete the active steering action;Because of the different travel distance of each wheel,in order to ensure pure rolling of each wheel,a torque distribution strategy based on the change of vertical load of the tire is designed.Through simulation comparison,it can improve the running condition of the vehicle,reduce the tire wear and extend the tire Life expectancy,improve vehicle driving stability.In this paper,from the perspective of improving the driving stability of four wheel drive vehicles,the torque distribution strategy of wheel motor is designed,and the control of the center of mass and yaw rate is carried out.Finally,the ideal control effect is achieved.Electric car to make a contribution to the initiative steering research.