Research On Hub Motor Distributed Drive Technology Of Electric Vehicle

With the global energy crisis and increasing demands on the environment,the negative impact of the rapid increase in the use of traditional fuel burning vehicles have become increasingly severe.In order to adapt to the requirements of global low-carbon,environmental protection and sustainable development,as one of the indispensable tools of human beings,the development of automobiles needs to find new direction.In this social environment,the hub-motor-driven electric vehicle with a simple structure,a wide range of power sources and high transmission efficiency has attracted increasing attention.The hub-motor-driven electric vehicles eliminate the centralized drive system for conventional fuel-fired vehicles,which greatly simplifies structure of the electric vehicle,saves space and makes the electrical layout of the vehicle more flexible.However,because of the independent driven of four hub motors and the increase of mass under the spring,the mass distribution of the whole vehicle changes,which brings about the low speed performance limitation of the hub motor,the speed coordination of each hub motor,and the stability of the vehicle control and communication system.This paper focuses on the development of electric vehicle prototype with wheel base 185cm and wheel tread 100cm,which uses two hub motors to drive independently,and deeply study its driving system,control system,driver information system and communication system.In the research work,the vehicle control structure adopts the bus + node layout.The nodes communicate with each other through the CAN bus.Each node uses the STM32 microcontroller based on the ARM Cortex-M3 core as the system microprocessor to complete node control.The driver's driving intention is collected through the throttle,direction machine and brake node,and transmitted to electronic differential node via the CAN bus.The electronic differential node combined with Ackermann steering model,throttle and steering angle input signals to calculate the left and right driving wheel target speed,and through obtaining the PID real-time closed-loop speed control by acquiring the three-phase hall signal of the hub motor,make the electric vehicle driving safely.