Active steering control based on the estimated tire forces

Steered vehicles on slippery roads tend to slide outward with less lateral force than on high friction roads. In this paper, an active steering contro l method is proposed such that the vehicles on slippery roads are steered a s if they are driven on high friction roads. In order to estimate the later al force at each the, a monitoring model is developed utilizing not only th e vehicle dynamics but also the roll motion. The estimated lateral force is compared with the optimal reference force and the difference is compensate d 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 a nd sinusoidal roads demonstrate the effectiveness of the proposed controlle r. The drivers with the controller can steer the vehicles as if they are al ways driving on the high friction road, because the deviation from the high friction road is accommodated by the proposed steering controller. This me thod can be realized with the steer-by-wire concept and is promising as an active safety technology.