Research On Electronic Differential Control System Of Wheel Drive Electric Vehicle

As the global energy crisis deepened and increasingly severe environmental pollution,the traditional car is facing obstacles,and the development of the car had to seek new directions.Wheel drive electric car,with its power source widely,simple structure,high transmission efficiency and the drive wheels can control independently,has attracted much attention.However,due to the wheel drive electric vehicles to remove the traditional internal combustion engine with the mechanical differential,with a simple structure,more freedom of control and other advantages,but also produced a car steering wheel driving wheel between the coordination of control issues-Electronic differential problem.Therefore,in order to ensure the stability and safety of the vehicle handling,to avoid the vehicle in the steering wheel due to the wheel slip or slip caused the vehicle out of control,must use the electronic differential control system to coordinate the control wheel.According to the above background,the front wheel turns and the rear wheels are used as the platform of the wheel motor drive,and the Ackerman steering model is used to calculate the speed of the two drive wheels according to the vehicle speed and steering angle.The output of the motor speed control signal PWM is adjusted by the PID neural network with PID controller as the model,and the actual speed of the drive wheel is obtained by detecting the Hall motor signal of each drive wheel.The actual rotation speed of each drive wheel and its target speed is taken as the input of the PID neural network to realize the closed-loop control of the driving wheel speed,so that the actual speed of the drive wheel follows the target speed.So as to achieve the vehicle steering when driving the two drive wheel differential coordination control to ensure vehicle stability.This paper first introduces the development trend of electric vehicle and the research status of electronic differential control system of wheel drive electric vehicle.By comparing the characteristics of different electronic differential control schemes,combined with the vehicle transmission structure studied in this paper,it is determined that the speed control electronic differential strategy based on Ackerman steering model is adopted for the two rear drive wheels.The MCU core chip STM32F103RBT6 is used as the system microprocessor,and the MCU minimum system,Hall signal isolation and shaping module,CAN communication module and power module are designed to complete the electronic differential control hardware platform.System software development environment selected by the United States Keil Software Corporation Keil uVision5,the use of modular thinking on the functional modules of the software design.Finally,the PCB schematic is designed and the hardware circuit is finished.On this basis,the feasibility and stability test of the electronic differential control system are carried out.