Tire pressure drop detecting device and method, as well as the tire pressure drop detecting program

摘要

PROBLEM TO BE SOLVED: To provide a device for detecting decrease in tire air pressure, capable of improving the performance of an air pressure decrease warning system without increasing calculation resources of an on-vehicle calculator.;SOLUTION: The device for detecting decrease in the tire air pressure includes a detector for the rotation speed information of a tire, a frequency characteristics estimating tool for estimating frequency characteristics of the rotation speed information, and a determining instrument for determining the decrease in the tire air pressure on the basis of the estimated frequency characteristics. The frequency characteristics estimating tool includes a parameter deciding tool for deciding a parameter of a linear model not less than third order by a Kalman filter; an input signal estimating tool for successively estimating an input signal to the linear model from the linear model whose parameter is decided and the rotation speed information by using the Kalman filter; a parameter deciding tool deciding the parameter of the linear model which is lowered to a second order from the estimated input signal and the rotation speed information by the Kalman filter; and a resonance frequency estimating tool for estimating resonance frequency in a twisting direction of the tire from the parameter.;COPYRIGHT: (C)2011,JPO&INPIT