Doppler-effect ground speed sensor for use with a brake system
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsShinji Ikeda, Masashi Mizukoshi
Life of this patent
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Abstract
Vehicle anti-lock brake control apparatus having wheel speed sensor for detecting actual speed of a vehicle wheel, solenoid-operated valve for regulating the wheel braking pressure, and controller for controlling the valve, on the basis of the detected actual speed, and vehicle ground-speed detected by ground-speed sensor. The controller controls the valve at a controlled duty cycle, which is determined on the basis of at least a wheel speed error and a time derivative of this error. The error is obtained as a deviation of the detected actual wheel speed from a target wheel speed obtained on the basis of the detected vehicle ground-speed.
Claims7
A Doppler-effect type ground-speed sensor including a transmitter attached to a body of the vehicle and transmitting a wave toward a road surface in a predetermined direction of propagation, a receiver attached to said body and receiving a portion of said wave which is irregularly reflected by said road surface, and a signal processor which provides an output representative of said ground-speed of the vehicle, on the basis of frequencies of said wave transmitted by said transmitter and said portion received by said receiver, wherein the improvement comprises:
- said receiver is spaced apart from said transmitter by a predetermined distance in one of opposite running directions of the vehicle in which said predetermined direction of propagation is inclined with respect to a direction perpendicular to the running directions.
Dependencies are inferred from the claim text.