Study on Effects of Transient Steering Efforts Characteristics on Driver's Steering Behavior

In the first half of this paper describes a new algorithm of an electric power steering system control. The problem of the vehicle with ordinary steering and the reason why it occurs physically are clarified. It is shown as the low damping of the transfer function of steering angle / steering torque at high speed. This is derived from interference between steering system and vehicle system. So, we strictly solved the controller using simple model, and then in order to maintain the stability of the controller, we approximated strict solution as simple controller, that is described as first order non-minimum phase transfer function. and we validate our result of analysis by driving test conducted with an actual vehicle.

In the second half, a study on the relationship between the steering characteristics and driver's steering operation in the driver-vehicle closed-loop system has been conduted. we developed a driving simulator controlled by a new algorithm, which can realize steering torque and angle independently. In this portion, dump ing and natural frequency of the transfer function of steering angle / steering torque effect the driving steering operational manner. The experiment showed that the driver's steering action was changed deeply related on the steering torque, haptic information, as well as visual information. At last, we proposed the directional character of the steering torque.