Method and apparatus for detecting air pressure in a tire using a basic wavelet function localized in time

摘要

The apparatus for detecting the air pressure of the tire includes an oscillating electric signal output section for outputting an oscillating electric signal including a vibration frequency component of a tire of a vehicle. A wavelet transformation section is provided for performing wavelet transformation of the oscillating electric signal outputted by the oscillating electric signal output section. A constant extraction section is provided for calculating mean values of the wavelet coefficients calculated by the wavelet transformation section at every predetermined interval of time, for obtaining an approximate curve of the second or greater order by a method of least squares using the mean values of the wavelet coefficients at the respective predetermined frequencies at every predetermined interval of time and for extracting a constant of the approximate curve. An air pressure estimating section is provided for estimating the air pressure of the tire based on the constant.