Abstract
As the cornering stiffness of tyre decreases on a wet surface, the performances of course tracking and course holding become worse.In order to compensate for the deterioration of the vehicle dynamics, drivers tend to operate the steering wheel in a different manner. In this paper, a new adaptive control model of a human driver is presented, using the theory of model reference adaptive control system (mrac). The word "adaptive" in this paper means that the steering gain of a driver is not constant but changeable, corresponding to the change of vehicle parameters. With this adaptive control model the computer simulation of the closed loop system is carried out when the driver is going to modify his steering manoeuvre on wet surfaces.