Research On Traction Control Strategy Of Four-wheel Independent Drive Electric Vehicle Based On Fuzzy Road Recognition

With the development of automobile industry,new energy vehicle is attracting people’s attention.Since the four-wheel can be controlled independently and the torque-speed is easy to measure,the four-wheel independent drive(4WID)electric vehicle has become an important representative of this field.The traction control technology is the key technology of four-wheel independent drive electric vehicle.When vehicle drives on the low adhesion road,the driving wheels often slip,the drive path may deviate from the track,and even lead to serious car accident.To improve the security and stability of the four-wheel independent drive electric vehicle,the traction control strategy bases on fuzzy road recognition is designed in this thesis.The main work is as follows:1.The thesis studys the 4WID electric vehicle structure and traction control technology.Further the research content includes vehicle control structure,the structure characteristics of in-wheel motor,the principle of the traction control technology,and the characteristics of traction control for 4WID electric vehicle.2.The thesis studys the mathematical model and the basic speed control method of the 4WID electric vehicle,and the reference coordinate system,automobile body model,wheel model and tire model are established.Then,the basic speed control method of 4WID electric vehicle is designed and verified by simulation.3.The traction control strategy of 4WID electric vehicle bases on fuzzy road recognition is designed in this thesis.In view of the complexity of the actual road and the different road corresponding to different optimal slip ratio,so the fuzzy recognition algorithm is designed in this thesis for real-time recognition wheels optimal slip ratio.Then,the traction control strategy is designed on the basis of the fuzzy recognition algorithm.Through the real-time adjustment of the traction force to control the wheel slip rate in the vicinity of the optimal slip ratio,the vehicle driving more stable and safe.Base on the above work,the control strategy of this paper is simulated in the single,docking,off and uphill conditions.The results of the simulation show that the vehicle can be stable and safe under the control of traction control strategy base on fuzzy road recognition,while the basic speed control strategy has poor control effect under low adhesion road.Compared with the traction control under different road recognition methods,the vehicle has better acceleration performance while driving under the control of traction control strategy based on fuzzy road recognition.