Research On Rear Wheel Differential Steering Control Of Electric Vehicle

The improvement of automobile popularity leads to more serious traffic accidents,energy shortage and environmental problems,and the development of fuel vehicles is limited.Electric vehicle has become the mainstream of future development because of energy saving and environmental protection.Therefore,all countries are actively studying pure electric vehicles and committed to putting them into the market as soon as possible.Distributed drive electric vehicle has gained extensive research and attention for its special structural characteristics and more performance advantages.However,the differential control of electric vehicles is a technical problem.In this paper,the differential steering problem of distributed electric vehicle was studied,the electronic differential system of electric vehicle was designed,and on this basis the path tracking problem of electric vehicle was further studied.The main contents of this paper are as follows:(1)Establishment of electric vehicle dynamics model and co-simulation platform.Firstly,the four-wheel dynamics model and the wheel dynamics model were established.After that,according to the unique dynamics structure of rear-wheel drive electric vehicle,the vehicle co-simulation platform including tire model and body model were established based on Simulink and Car Sim simulation software to prepare for the following research.(2)Research on stability control of rear wheel differential electric vehicle.Firstly,the optimization objective of electronic differential system was determined,and the stability control strategy of electronic differential based on model predictive control(MPC)was designed.In the optimization solution,the optimization objective was limited according to the actual conditions,the rear wheel torque meeting the control target s obtained after optimization,so as to realize the differential control of electric vehicle.At the same time,in order to verify the superiority of the electronic differential control strategy designed,the electronic differential stability control strategy based on fuzzy control was compared and analyzed,and two simulation tests were designed for the front wheel angle step and sinusoidal conditions to compare the effectiveness of the electronic differential control system.(3)Research on electric vehicle path tracking control based on electronic differential.Considering that the automobile will develop in the direction of intelligence in the future,rear differential electric vehicle path tracking control strategy based on the MPC was design,through the optimization of objective function,the front wheel angle and rear wheel torque which can realize path tracking control and differential control at the same time are obtained.Through the joint simulation test under different reference path analysis,the results showed that the stability of electric vehicle with rear wheel differential control was improved compared with that without rear wheel differential control on the premise of effective reference path tracking.