Patent ID: 7013208

Claim:
A sliding, integral, and proportional controller for providing anti-skid braking control for an aircraft having a plurality of tires and brakes, comprising: a reference velocity subsystem generating a reference velocity signal (Vref) based upon an input wheel velocity signal Vw); a velocity error ratio subsystem generating a modified slip ratio signal (S mod ) based upon a ratio of the difference between the reference velocity and the wheel velocity to the reference velocity; and a main controller subsystem receiving the reference velocity signal and the modified slip ratio signal, the main controller subsystem generating a control command output signal indicative of a command braking pressure responsive to the reference velocity signal and the modified slip ratio signal, wherein the main controller subsystem comprises: a one dimensional sliding mode controller subsystem to determine an estimated net wheel torque signal; an adaptive threshold subsystem for generating an adaptive threshold based upon the modified slip ratio signal (S mod ) and a clock signal; means for summing a first integral gain based upon the estimated net wheel torque signal and the adaptive threshold, a deep skid signal (DS) based upon the modified slip ratio signal (S mod ), the wheel velocity signal (Vw), the reference velocity signal (Vref), a tire rolling radius, a predetermined deep skid limitation (Slim) of the S mod signal, and first and second function coefficients, and a modification of the initial braking command signal to avoid S mod signals that are too small or negative, to provide an output sum; a proportional controller subsystem receiving the output sum from the means for summing and generating an output signal responsive to the output sum to prevent sudden deep skids; and a pressure limiter for limiting the command braking pressure.