A Torque Distribution Method Using CCD Cameras That Is Suitable for Electric Vehicles Driven by Front and Rear Wheels Independently

Abstract

This paper describes a method to distribute driving and breaking torques to electric vehicles (EVs) driven by front and rear wheels independently while estimating the distance between an obstacle and the running vehicle and the road surface situations using CCD cameras. The method is comprised of braking torque distribution procedures to control wheel locks generated due to load movement occurring every time braking operations are performed and driving torque distribution procedures to control wheel spins occurring when vehicles are accelerated on bad roads with low friction coefficients. The former distributes the braking torque to the front and rear wheels based on the distance between the vehicle and an obstacle which is calculated using the information acquired from CCD cameras while taking the load movement into consideration. The latter determines the driving torque distributed to the wheels based on a friction coefficient predicted from the front road surface state obtained from the CCD cameras. Effectiveness of the torque distribution method is verified through simulations and experiments.