Road surface condition estimating method, road surface condition estimating tire, road surface condition estimating apparatus, and vehicle control apparatus

A road surface condition estimating apparatus comprising:

• a reception means for receiving the wirelessly transmitted data of vibration level or vibration level computed value from a road surface condition estimating tire;
• and
• a road surface condition estimating means for estimating a road surface condition based on the vibration level or the vibration level computed value;
• and
• the road surface condition estimating tire comprising:
• a tire vibration detecting means disposed on the air chamber side of an inner liner in a tire tread area, said tire vibration detecting means detecting the vibration of a tire of a running vehicle;
• a pre-trailing domain signal extracting means for extracting signals of a pre-trailing domain, which is a domain before the trailing position estimated from a peak position of said tire vibration detected by said tire vibration detecting means;
• a post-trailing domain signal extracting means for extracting signals tire vibration in the post-trailing domain, which is a domain after the trailing position estimated from the peak position of said tire vibration detected by said tire vibration detecting means;
• a band-pass filter for extracting a signal in the post-trailing domain, whose lower-limit frequency of which being 0.5 kHz or above and upper-limit frequency of which being 4 kHz or below out of the signal in the post-trailing domain, and a signal in the pre-trailing domain, whose lower-limit frequency of which being 2 kHz or above and upper-limit frequency of which being 10 kHz or below out of the signal in the pre-trailing domain by inputting said signals of the post-trailing domain extracted by the post-trailing domain signal extracting means and signals of the pre-trailing domain extracted by the pre-trailing domain signal extracting means;
• a vibration level calculating means for calculating a vibration level which is the vibration level of the signal in the post-trailing domain and a vibration level which is the vibration level of the signal in the pre-trailing domain, which are extracted by the band-pass filter;
• a means for calculating a vibration level computed value using said calculated vibration level in the post-trailing domain and vibration level in the pre-trailing domain;
• and
• a means for wirelessly and automatically transmitting data of the vibration level or vibration level computed value to the vehicle body side;
• and
• a transmission means for wirelessly and automatically transmitting information of the estimated road surface condition to another vehicle,
• wherein the frequency band for calculating the vibration level is higher in pre-trailing domain than the band in the post-trailing domain.