Research On The Application Of Information Fusion Technology In 4WD Automobile Driving System

Four wheel drive(4 Wheel Drive,4WD)electric vehicle(EV)is an important subject in the development of automotive.Since the situation in off-road conditions is complex,how to assign driving force properly becomes an important issue.In order to solve this problem,the velocity and attitude information of vehicle is essential and important.It becomes an important factor to acquire the velocity and attitude information accurately,which influence whether the driving force is distributed reasonably.Focus on application of information fusion techniques in Electric 4WD vehicle drive system and strategy of driving force distribution,the main works includes:First of all,according to project requirements,a circuit board is designed for information collection,which integrated accelerometer,gyroscope and GPS module.All of the information are collected by sensors and sent to controller STM32F407.The information will be transmitted to PC after processing through the serial port to display on the master.In addition,for ease of debugging outdoor,a Nokia 5110 display screen is needed on the slave.Secondly,because of the complex terrain in off-road conditions and relatively large measurement error of GPS at low speed,we need accelerometer to compensate error to make the measurement in acceptable accuracy.In order to reduce the integration error of gyroscope’s measurement angle,accelerometer is added for correction.So the velocity is obtained by fusing GPS signals and accelerometer signals using Kalman filtering,while angle is acquired by fusing accelerometer signals and gyroscope signals.Fusion information can not only improve the measuring accuracy of mix-measurement signals effectively,but also improve the robustness of the system.Finally,the control strategy of driving force distribution is modeled and analyzed.According to vehicle straight driving model,built models of in-wheel motor in Simulink and vehicle parameters with road conditions in CarSim,then combine them to simulate.The vehicle’s load torque determines by vehicle velocity,wheel speed,pitch and normal reaction road effect on driving wheel.It’s a basis to adjust the output torque according to the calculated torque distribution ratio,which coordinates the distribution of front and rear drive torque within acceptable slip ratio.For the problem of solving 4WD electric vehicle driving force distribution under the off-road condition,accurate velocity and attitude calculated are combined by information fusion technology,then the strategy of driving force distribution under straight road condition is explored.The study shows information fusion technology can get more accurate velocity and attitude,which make the output torque smoother,and improved calculated torque distribution strategy reduces slip ratio as well as improves energy efficiency ratio.