Driver steering sensitivity design using road reaction torque observer and viscous friction compensation to Active front steering

In recent years, the demand for safer vehicles has increased. According to traffic accident reports prepared by the Metropolitan Police Department in Japan, almost all traffic accidents are caused by human errors such as driver negligence or operational mistakes. Therefore, future technologies need to precisely detect driver´s mistakes and adopt active control in order to increase vehicle safety. For example, Active front steering (AFS) is an effective technique to stabilize motion control after the detection of dangerous motion in a vehicle, such as a slip. However, if AFS intervenes excessively during the steering process, it becomes difficult to resolve the interference between driver steering and automatic steering by AFS. As a result, vehicles are at present rarely equipped with AFS. This paper proposes a reactive torque control method based on road reaction torque observer and hysteresis control method based on driver sensitivity to a human-friendly AFS system. And this paper discusses how an experimental device was used to verify the effectiveness of this control method.