Research On Electronic Differential For In-Wheel Motor EV Based On Wheel Speed Tracking Control

At present,the driving system of pure electric vehicles is mainly divided into centralized driving and distributed driving.The distributed driving mode is a unique driving method for electric vehicles and is an important development direction of pure electric vehicles.The distributed drive eliminates the complicated mechanical transmission mechanism and drives the electric vehicle with a wheel-side motor drive or a wheel in-wheel motor,which greatly simplifies the chassis structure and reduces the quality of the vehicle.In-wheel motor-driven electric vehicles are divided into two-wheel motor drives and four-wheel motor drives.Four-wheel drive electric vehicles have more power,stability and ability to escape,and have more development potential,but their control is more complicated.Therefore,this paper takes distributed four-wheel in-wheel motor-driven electric vehicles as the research object,and conducts a research on the electronic differential speed of the in-wheel motor based on wheel speed tracking control.This paper makes an in-depth study on the steering method and differential control strategy of the four-wheel in-wheel motor electric vehicle,and achieves differential steering by improving the steering method and coordinating the real-time speed of the in-wheel motor.The main research includes the following aspects:With the two-degree freedom steering model to analyze the basic working principles of Ackerman steering,reverse steering,diagonal driving,and pivot steering,and establish the mathematical relationship between the steering angle of each wheel of the four-wheel in-wheel motor electric vehicle and the vehicle steering angle;The mathematical relationship between the speed of each wheel and the speed of the vehicle.Based on the wheel speed tracking control method,combined with the relevant principles of the four-wheel independent steering electronic differential technology,and aiming at steering flexibility,this paper proposes a low-speed four-wheel in-wheel motor electric vehicle based on the wheel speed tracking control method in multiple steering modes Four-wheel differential control strategy.Use MATLAB/Simulink software to build a vehicle control logic that integrates four-wheel electronic differential control strategies in multiple steering modes,and combines the in-wheel motor model and driver model to perform low-speed snake-like conditions and steps on the electronic differential control strategy Simulation of operating conditions,the results show that the strategy can achieve the vehicle steering control requirements and achieve better differential performance.The design of the realization of the four-wheel electronic differential technology,the introduction and selection of the hardware equipment used.Focus on the communication between the vehicle controller and the motor controller.This article selects CAN bus as the vehicle network system,and uses the motor controller and the vehicle controller as the network nodes to develop the CAN communication protocol.And using our college students’ Formula Racing as an experimental platform,the rapid prototyping technology was used to verify the communication network between the vehicle controller and the motor controller.