| 摘要 |
PURPOSE:To improve the estimation precision of the tire absolute velocity of a car body by respectively detecting the vibration frequency components under springs of a vehicle in connection with front and rear wheels when the vehicle travels, and estimating the absolute velocity of the car body on the basis of the phase difference between signals and the length of a wheel base. CONSTITUTION:Wheel speed sensors composed of pick-up coils 3a to 3d are provided in correspondence with respective tires 1a to 1d of a vehicle, and A.D signals having periods according to the tire rotational speeds are output therefrom so as to be input into an ECU 4. The vibration frequency components under springs of the vehicle is respectively detected from the detected signals of the wheel speed sensors in connection with front and rear wheels, and the phase lag tau of the front and rear wheels is found in view of rear wheels travelling on the same road surface of as that of the front wheels. That is, when wheel speed signals of the front and rear wheels are taken as F(t), R(t), the phase lag, tau is found from the formula; R(t)=F(t-tau). When a wheel base of the vehicle, as the known value, is taken as L, the absolute velocity VAB is calculated from the formula VAB=L/tau. |
