Active steering control based on the estimated tire forces

Steering of vehicles on a slippery highway is a difficult task for most passenger car drivers. The vehicles tend to slide outward with less lateral forces than on normal roads. When the drivers notice that their vehicles on a slippery highway start to depart from the cornering lane, most of them easily panic and make a sudden steering and/or braking, which in turn may induce spin-out and instability on their vehicles. In the paper, an active steering control method is proposed such that the vehicles on slippery roads are steered as if they are driven by experienced drivers. Those drivers have better perceptive capability of judging the slippery status and they respond faster with smooth compensatory action. In the proposed method, the estimated lateral forces acting on the steering tires are compared with the reference values and the difference is compensated by the active steering method. A fuzzy logic controller is designed and its performance is evaluated on a hardware-in-the-loop simulation system. This method can be realized with a steer-by-wire concept and is promising as an active safety technology