A method of road condition estimation and feedback utilizing haptic pedal

These days, electric vehicles are developing rapidly. Electric vehicles are expected to be alternative to the conventional gasoline engine vehicles and many researchers have studied motion control of electric vehicle. In this paper, a method how to feedback the road condition to the driver, which utilizes real-time road condition estimation method using sensor information of traction motor, is proposed. Fixed trace (FT) algorithm which is one of real-time identification methods and driving force observer which estimates driving force and friction coefficient are used to estimate road condition. To feedback road condition to the driver, haptic pedal system which uses a motor set in the acceleration pedal is proposed. In haptic pedal motor, disturbance observer and reaction torque observer is implemented to estimate driver input to the acceleration pedal without using force sensor. Simulation is carried out to show the validity of the proposed method.