Vehicle skid control system
First Claim
1. A vehicle skid control system for preventing skidding of a vehicle caused by excessive braking force, the vehicle having braking means including a brake pedal whereby braking force is applied, the pitch angle of the vehicle varying with the braking force and with the deceleration of the vehicle, said vehicle skid control system, comprising. gravity independent pitch angle detecting means mounted on the vehicle for detecting a variation in the pitch angle of the vehicle in deceleration;
- and control means coupled between the pitch angle detecting means and the braking means for reducing the braking force when the pitch angle exceeds a predetermined level.
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Accused Products
Abstract
A skid control system which successfully prevents a vehicle from slipping with its wheels being locked due to excessive braking force during braking, known as '"'"''"'"''"'"''"'"'skid condition'"'"''"'"''"'"''"'"', comprises two Doppler radars including respective transmitting and receiving antennae. The radars are provided on the body of the vehicle at the same angle of declination relative to a plane parallel to the bottom surface of the vehicle body. One of the radars is directed down-forward and the other is directed down-backward. A signal component proportional to the pitch angle of the body of the vehicle during deceleration may be sensed by combining two signals produced by the two radars. The excessive braking force is controlled by the signal component.
65 Citations
7 Claims
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1. A vehicle skid control system for preventing skidding of a vehicle caused by excessive braking force, the vehicle having braking means including a brake pedal whereby braking force is applied, the pitch angle of the vehicle varying with the braking force and with the deceleration of the vehicle, said vehicle skid control system, comprising. gravity independent pitch angle detecting means mounted on the vehicle for detecting a variation in the pitch angle of the vehicle in deceleration;
- and control means coupled between the pitch angle detecting means and the braking means for reducing the braking force when the pitch angle exceeds a predetermined level.
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2. A vehicle control system as claimed in claim 1, wherein the pitch angle detecting means comprises radar means.
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3. A vehicle skid control system as claimed in claim 1, wherein the pitch angle detecting means comprises a pair of radar units mounted on the bottom of the vehicle, one of the radar units having a transmitting and receiving antenna at a predetermined angle of declination relative to a plane parallel to the bottom of the vehicle and directed downward and forward and the other of the radar units having a transmitting and receiving antenna at the predetermined angle of declination relative to the plane and directed downward and backward.
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4. A vehicle skid control system as claimed in claim 3, wherein each of the radar units is a Doppler radar unit.
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5. A vehicle skid control system as claimed in claim 4, wherein each of the Doppler radar units produces a Doppler signal and wherein the pitch angle detecting means further comprises means for combining the signals produced by the radar units to produce a signal component proportional to the pitch angle of the vehicle during deceleration, and means for supplying the signal component to the control means to reduce the braking force.
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6. A vehicle skid control system as claimed in claim 5, wherein the control means comprises level comparison means for comparing the levels of signals supplied thereto, integrating circuit means for integrating a signal supplied thereto and signal dividing means for dividing the signal component into two signals, supplying one of the divided signals directly to the level comparison means and supplying the other of the divided signals to the level comparison means via the integrating circuit means whereby the level comparison means compares the levels of the signals supplied thereto and determines the coincidence point of the levels of the divided signals and produces an output signal in accordance with the comparison, and wherein the control means further comprises actuator means coupled in the braking fluid pressure system of the braking means for varying the fluid pressure applied to the brakes of the vehicle thereby varying the braking force, and means for supplying the output signal of the level comparison means to the actuator means to control the operation thereof.
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7. A vehicle skid control system as claimed in claim 5, wherein the control means comprises level comparison means for comparing the levels of signals supplied thereto, potentiometer means connected to the level comparison means for providing a signal voltage corresponding to a predetermined standard pitch angle and means for supplying the signal component directly to the level comparison means whereby the level comparison means compares the levels of the signal component and the signal voltage and determines the coincidence point of the levels of the signal component and the signal voltage and produces an output signal in accordance with the comparison, and wherein the control means further comprises actuator means coupled in the braking fluid pressure system of the braking means for varying the fluid pressure applied to the brakes of the vehicle thereby varying the braking force, and means for supplying the output signal of the level comparison means to the actuator means to control the operation thereof.
Specification