To detect variation in tire outer diameter during a city drive in which right/left turns and slow-speed moving are frequently made.
A signal acquisition part 102 acquires vehicle speed pulses of right and left tires generated as a vehicle moves. A direction change quantity acquisition part 103 acquires information on a quantity of change in direction to which the vehicle turns. A calculation part 104 calculates a direction change quantity coefficient indicative of a difference in turning quantity between the right and left tires on the basis of the vehicle speed pulses and the information on the quantity of change in direction. A determination part 105 determines whether the direction change quantity coefficient satisfies a first condition under which variation in outer diameter of driving wheels is recognized by comparing the direction change quantity coefficient with a direction change quantity coefficient reference value stored in a storage part 101. When the first condition is satisfied, a correction part 106 corrects the direction change quantity coefficient reference value and a distance coefficient reference value as a reference value for measuring a movement distance of the vehicle.
KATO YOSHIKO
KUTSUWA YOSHIKI
TANAKA KAZUTOSHI
| JPH06186046A | 1994-07-08 | |||
| JP2007178278A | 2007-07-12 |
| WO2011046185A1 | 2011-04-21 | |||
| US6381524B1 | 2002-04-30 |