Patent ID: 6577941
Filing Date: 2003-06-10
Classification: B60T

Abstract:
An apparatus for determining a condition of road surface comprising: rotational speed detecting means for periodically detecting rotational speeds of four tires of a vehicle; first computing means for computing a slip ratio from measurement values of the rotational speed detecting means; second computing means for obtaining a relational formula between the slip ratio and either acceleration or deceleration of the vehicle; and friction coefficient judging means for judging a coefficient of friction occurring between a road and a tire on the basis of a slope of the relational formula obtained by the second computing means,moving average calculating means for calculating a moving average for the acceleration or deceleration of the vehicle and the slip ratio in predetermined time; and third computing means for obtaining a relational formula between the acceleration or deceleration of the vehicle and the slip ratio on the basis of the value obtained by the moving average.