To provide the robustness in the tire size change to the determination of the road surface conditions, while determining the road surface condition by dividing a time-series waveform of tire vibrations without detection of the peak positions or measurement of the wheel speed.
A time-series waveform of tire vibrations detected by a tire vibration detecting means is windowed by a windowing means. Time-series waveforms of tire vibration are extracted from the respective time windows, feature vectors X are calculated therefor, and then likelihoods Z for road-surface HMMs (hidden Markov models) are calculated. The likelihoods Z1 to Z5 calculated for the respective road-surface HMMs are compared with one another, and a road surface condition corresponding to the road-surface HMM showing the highest likelihood is determined to be the condition of the road surface on which the tire is running.
HIGUCHI TOMOYUKI
MATSUI TOMOKO
RES ORG INFORMATION & SYSTEMS
| JP2007055284A | 2007-03-08 |
Miyazono Yasuo