Active Steering Control Based on the Estimated Tire Forces

Abstract

Steered vehicles on slippery roads tend to slide outward with less lateral force than on high friction roads. In this paper, an active steering control method is proposed such that the vehicles on slippery roads are steered as if they are driven on high friction roads. In order to estimate the lateral force at each tire, a monitoring model is developed utilizing not only the vehicle dynamics but also the roll motion. The estimated lateral force is compared with the optimal reference force and the difference is compensated by the active steering controller. A fuzzy logic rule is designed for the active controller and its performance is evaluated on a steering Hardware-In-the-Loop Simulation (HILS) system. Steering results on slippery curved and sinusoidal roads demonstrate the effectiveness of the proposed controller. The drivers with the controller can steer the vehicles as if they are always driving on the high friction road, because the deviation from the high friction road is accommodated by the proposed steering controller. This method can be realized with the steer-by-wire concept and is promising as an active safety technology.