US 5,180,214 AGranted

Servo-type phase-locked loop anti-skid brake control system

AssigneeNational Science Council

InventorsEdge C. Yeh, Jiunn Y. Wang

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Abstract

An anti-skid brake control system (ABS) utilizing a phase-locked loop (PLL) for controlling the brake mechanism of a landing aircraft. The PLL control system tracks the angular velocity of the nose wheel of the aircraft as a reference signal for locking the angular velocity of the main wheel of the aircraft such that the wheel slip is maintained at a constant value. The PLL control system has a phase detector which takes the signals from both wheel speed detectors and is capable of generating accordingly a frequency error signal and a phase error signal. A circuit will generate an electrical signal, the magnitude of the electrical signal being in accordance with the magnitude of the frequency error signal and the magnitude of the phase error signal. A driving member will drive in accordance with the magnitude of the electrical signal the brake mechanism connected to the main wheel to apply a brake force thereto. The main wheel thus braked will cause the aircraft to be decelerated, the deceleration of the aircraft in turn cause the angular speed of the nose wheel and the main wheel to be slowed down. The slowed-down speeds are in turn detected by the wheel detectors and thus forming a feedback loop.

Claims6

Dependent claims

An anti-skid brake control system for controlling brake mechanisms of a vehicle, the vehicle having at least a first wheel and at least a second wheel, when braking the vehicle the brake mechanisms applying a brake force to the second wheel and the first wheel being under free rolling, the brake control system comprising:

a first wheel speed detector mounted on the first wheel and capable of sending out a periodic first signal, the frequency of which indicating the angular speed of the first wheel;
a second wheel speed detector mounted on the second wheel and capable of sending out a periodic second signal, the frequency of which indicating the angular speed of the second wheel;
a frequency error detector, responsive to the first signal and the second signal, for generating an output frequency error voltage in proportion to the difference between the frequency of the first signal and the second signal;
a phase error detector, responsive to the first signal and the second signal, for generating an output phase error voltage in proportion to the phase error between the first signal and the second signal;
summing means, coupled to said frequency error detector and said phase error detector, for generating an output control voltage, the magnitude of the control voltage being the summation of the frequency error voltage, the phase error voltage, and a predetermined bias voltage;
means, responsive to the control voltage, for driving the brake mechanisms to apply a brake force in accordance with the control voltage to the second wheel.

3 more elements

Dependencies are inferred from the claim text.