Patent ID: 7945429

Claim:
A tire model determining method of determining a first-order lag model which simulates a transient response of a tire which is rolling from measured transient response data of the tire, the transient response data generated by giving the tire a temporally varying physical amount that sets a rolling condition of the tire, comprising the steps of: initially setting a time constant of the first-order lag model to introduce a response function of a first-order lag response in the first-order lag model; performing a regression calculation which includes: obtaining, as time-series data of a transient response of the physical amount, effective data of the physical amount by calculating a convolution integral of the introduced response function of the first-order lag response and a time gradient of time-series data of the physical amount which has been given as the rolling condition to the tire; performing a least square regression on a characteristic curve that represents values of the measured transient response data of the tire with respect to values of the effective data to obtain a single smooth curve by using a curve function for representing a curve; and calculating a sum of square residuals between a least square regression curve obtained in the least square regression and the characteristic curve; and determining the first-order lag model by correcting the set time constant and repeating the regression calculation, until the calculated sum of square residuals is minimized or until the sum of square residuals reaches a given value or lower, and by determining a time constant that minimizes the sum of square residuals or a time constant that makes the sum of square residuals equal to the given value or smaller, as an optimum time constant that defines the first-order lag response.