Patent ID: 6650988
Filing Date: 2003-11-18
Classification: B60T

Abstract:
A method for judging road surface conditions, comprising the steps of: periodically detecting rotational information of tires of four wheels of a vehicle; storing the rotational information of the respective tires; calculating a vehicle velocity from the rotational information; calculating an acceleration/deceleration of the vehicle; calculating a slip ratio of left-sided front and rear wheels and right-sided front and rear wheels and a slip ratio of front and rear wheels, respectively; calculating an amount of fluctuation in differences in slip ratios between the right and left wheels; obtaining a linear regression coefficient and a correlation coefficient between the slip ratio of the front and rear wheels and the acceleration/deceleration of the vehicle; and setting a threshold for judging road surface conditions on the basis of the linear regression coefficient if the amount of fluctuation is a specified value.