Driving and braking torque control methods for securing safe running of front-and-rear-wheel-independent-drive-type electric vehicles (FRID EVs)

Abstract

This paper describes driving and braking torque control methods for front-and-rear-wheel-independent-drive type electric vehicles (FRID EVs); the methods are based on the distance between an obstacle and the running vehicle and the road surface condition, which are estimated using CCD cameras. The methods comprise three procedures: (i) a procedure to automatically control the braking torque on the basis of the estimated distance, (ii) a procedure to distribute the driving and braking torques to the front and rear wheels by using the friction coefficient estimated through the CCD cameras, and (iii) a procedure to control the slip ratios for the compensation of the error in the estimated friction coefficient. The effectiveness of the torque distribution method is mainly verified through simulations