Analysis And Control Of Steering Characterstics Of Hub-Driven Electric Vehicles

With the continuous development of science and technology society,the number of automobiles is increasing,and the environmental pollution caused by automobile exhaust emissions is becoming more and more serious.Therefore,new energy vehicles are gradually occupying the development market of future vehicles.At the same time,with the improvement of vehicle requirements,more in line with the trend of four-wheel steering technology is applied to hub-driven electric vehicles.Hub-driven electric vehicle four-wheel steering technology is not only energy-saving and environmentally friendly,but also can improve the vehicle steering flexibility and handling stability,which is the main direction of the future development of hub-driven electric vehicles.This paper takes the chassis structure of hub-driven EV as the research object,and studies the four-wheel steering technology of hub-driven EV.The specific research contents are as follows:(1)According to the current social development trend,the research background and significance of the subject are briefly introduced,and the research status of hub-driven electric vehicles and four-wheel steering technology at home and abroad is briefly summarized.(2)The vehicle structure was designed by referring to the structural parameters and performance indicators provided by the target vehicle.Based on the performance index,the matching design of the vehicle's dynamic performance was carried out,and the hub motor and power battery were selected according to the design results.The design of the braking system mainly considers the unique advantages of the electric vehicle driven by the hub motor.According to the mass and load of the vehicle to determine the basic parameters of the suspension,considering the structural characteristics of four wheel steering,the design of a semi-supported shaft independent rear suspension for the matching and connection of the rear wheel steering,the front suspension is still independent Mc Pherson suspension;The front wheel of four-wheel steering system is designed as a mechanical steering system,and the rear wheel is an independent steering system with electric power.According to the designed structure,the whole vehicle structure was arranged and the vehicle model was built with CATIA software.(3)Import the vehicle model into Adams software,and establish the tire and road model.The vehicle model is adjusted by applying driving and connecting pairs.According to the national standard,the simulation tests of snake shape,steady state steering and minimum turning radius are established.The results show that the vehicle model has good control stability.(4)With two degrees of freedom vehicle model is established for the ideal model,set up in MATLAB/Simulink software with horizontal pendulum angular velocity and the centroid side-slip Angle and the difference between the ideal value for the input,the rear wheel Angle changes for the output of fuzzy controller,with Adams software and the joint control of the vehicle model,analysis Angle step input and sinusoidal test and simulation test under the steering Angle pulse control effect.The results show that the fuzzy controller can effectively reduce the lateral deflection Angle and yaw velocity of the center of mass and improve the operating stability.(5)Build the experimental platform of hub-driven electric vehicle,process the designed parts according to the vehicle model established in CATIA and the actual process conditions,and complete the construction of the vehicle experimental platform.