| 摘要 |
PROBLEM TO BE SOLVED: To enable accurate estimation of an air pressure even when fluctuation occurs to the resonance frequency of wheel speed data calculated for estimation of a tire air pressure and a variation of a tire radius. SOLUTION: In steps S100-S110, a resonance frequency is computed from wheel speed data detected at each of wheels, and an arithmetical means of the resonance frequency is obtained every 1 second. In steps S112 and S114, by selecting only resonance frequencies in already set selection range,αresonance frequencies are stored and in a step S116, an average value of selected data is set as a finally smoothed rotation state amount and used for estimation of the tire air pressure. Further, the average value is set and varied as a central value in a next selection range. This constitution, since even when a wide fluctuation occurs to the resonance frequency, a selection range is changed following the fluctuation, selects a resonance frequency near a true value and makes accurate estimation of an air pressure possible. COPYRIGHT: (C)2003,JPO
|
