METHOD AND APPARATUS FOR ESTIMATING ROAD SURFACE STATE AND TIRE RUNNING STATE, ABS AND VEHICLE CONTROL USING THE SAME

摘要

A wheel vibration information signal detected by an acceleration sensor (11) mounted on a wheel (1) or an in-tire gas pressure fluctuation information signal detected by a pressure sensor (31) mounted in a tire is subjected to frequency analysis by frequency analysis means (14 (34)), so as to detect the vibration spectrum or the pressure fluctuation spectrum band value. The vibration level of the detected band is compared to a vibration level correspondence table (15T) showing the relationship between the road surface friction coefficient mu stored in the vibration level storage means (15) and the vibration level. Alternatively, the detected pressure level is compared to a pressure fluctuation level correspondence table (35T) showing the relationship between the road surface friction coefficient mu stored in the pressure fluctuation level storage means (35) and the pressure fluctuation level. Thus, it is possible to accurately estimate the value of road surface friction coefficient mu, thereby improving the vehicle safety.