Optimal Control for Steady State Drifting of RWD Vehicle

Abstract

Drifting is a cornering technique with large angle of sideslip, which might be useful in some cornering conditions when full handling capacity over the linear region of the wheel slip-tire friction characteristic is imperative. In this work, steady state cornering of a RWD vehicle on plane, with constant speed, sideslip and radius of curvature, was simplified via the single track vehicle model. In addition, BNP magic formula, along with MNC tire model, was used to estimate tire frictions. The computer program was developed, based on EOMs derived via body fixed coordinate, in order to calculate a suitable cornering speed and corresponding open-loop driving control inputs, consisting of steering angle and rear slip ratio, for a given radius of curvature and vehicle sideslip. The other set of EOMs, in terms of vehicle states and driving control inputs, was derived refer to n-t coordinate; also, linearized so that the state space description could be constructed. Eventually, LQR stabilizing controller had been designed and simulated via MATLAB. According to the results of simulation, any state deviation could be regulated to the desired steady state. The development of automatic drifting assistant may be feasible in the very near future.