Method and apparatus for estimating road surface state and tire running state, abs and vehicle control using the same

摘要

The frequency of an information signal indicative of the vibration of a wheel detected by an acceleration sensor 11 mounted to a wheel 1 or the frequency of an information signal indicative of a change in the pressure of a gas in a tire detected by a pressure sensor 31 installed in the tire is analyzed by frequency analyzing means 14 ( 34 ), the band value of the obtained vibration spectrum or pressure change spectrum is detected, and a vibration level or pressure change level at the detected frequency band is compared with a vibration level table 15 T showing the relationship between road friction coefficient mu and vibration level stored in vibration level storage means 15 , or a pressure change level table 35 T showing the relationship between road friction coefficient mu and pressure change level stored in pressure change level storage means 35 to estimate a road friction coefficient mu. Therefore, it is possible to estimate the value of road friction coefficient mu accurately and improve the safety of a car.