Automatic pitch axis control system for aircraft

Claim 2

In combination in a pitch axis control system, means for achieving short term stability of an aircraft comprising: first means for generating a first signal representative of the change in vertical velocity of said aircraft; second means for generating a second signal representative of vertical acceleration of said aircraft; third means for generating a third signal representative of pitch rate of said aircraft; fourth means for combining said first, second, and third signals; and fifth means including longitudinal control actuator means coupled between said fourth means and the control surfaces of said aircraft.

Claim 3

The invention according to claim 1 wherein said first means comprises: an accelerometer disposed in said aircraft for detecting accelerations of said aircraft in a vertical plane with respect to the ground; high pass filter circuit means coupled to the output of said accelerometer; and integrator circuit means coupled to the output of said high pass filter circuit means to integrate the signals representative of said accelerations of said aircraft to provide said first signal.

Claim 4

The invention according to claim 1 wherein said second means comprises: an accelerometer disposed in said aircraft for detecting accelerations of said aircraft in a vertical plane with respect to the ground; and band pass filter circuit means coupled to the output of said accelerometer to provide said second signal.

Claim 5

The invention according to claim 1 wherein said third means comprises: a pitch rate gyro disposed in said aircraft for detecting pitch rates of said aircraft; and band pass filter circuit means coupled to the output of said pitch rate gyro for providing said third signal.

Claim 6

In combination in a pitch axis control system for an aircraft; first means for generating a first signal representative of the angular deviation from the glide slope centerline; second means including first multiplier circuit means connected in series circuit to said first means having a gain varying as a function of altitude above terrain for generating a second signal representative of distance from glide slope centerline; third means for producing a third signal including high pass filter means representative of vertical acceleration of said aircraft; fourth means for combining said second signal and said third signal at the input of an integrator circuit for producing a fourth signal at the output of said integrator circuit representative of vertical velocity of said aircraft. fifth means for generating a fifth signal representative of commanded vertical velocity of said aircraft. sixth means for combining said second signal, said fourth signal, and said fifth signal to null or cancel said second signal; and seventh means including longitudinal control actuator means coupled between said sixth means and the control surfaces of said aircraft.

Claim 7

In combination in a pitch axis control system for an aircraft; first means for generating a first signal representative of the angular deviation from the glide slope centerline; second means including first multiplier circuit means connected in series circuit to said first means having a gain varying as a function of altitude above terrain for generating a second signal representative of distance from glide slope centerline; third means for producing a third signal including high pass filter means representative of vertical acceleration of said aircraft; fourth means for combining said second signal and said third signal at the input of an integrator circuit for producing a fourth signal at the output of said integrator circuit representative of vertical velocity of said aircraft. fifth means for generating a fifth signal representative of commanded vertical velocity of said aircraft. sixth means for combining said second signal, said fourth signal, and said fifth signal to null or cancel said second signal; and seventh means including longitudinal control actuator means coupled between said sixth means and the control surfaces of said aircraft.

Claim 8

The invention according to claim 5 further including pitch rate detector means for producing a signal representative of the pitch rate of said aircraft, and band bass filter circuit means coupled between said pitch rate detector means and said sixth means.

Claim 9

An aircraft pitch axis control system for providing pitch axis control signals at the system output terminal thereof comprising in combination: first circuit means for providing a first signal representative of vertical acceleration of said aircraft; high pass filter circuit means responsive to said first signal for providing a second signal; second circuit means for combining a plurality of input signals at the input terminals thereof and providing an output signal at an output terminal thereof; third circuit means for providing a third signal representative of glide slope error of said aircraft; first gain controlled amplifier circuit means responsive to said third circuit means for providing a fourth signal, and means for coupling said second and fourth signals respectively to said input terminals of said second circuit means; third circuit means for combining a plurality of input signals at the input terminals thereof and providing an output signal at an output terminal thereof, and means for coupling said output terminal to said system output terminal; fourth circuit means for coupling said third signal to a first of said plurality of input terminals of said third circuit means; a first series circuit path including low pass filter circuit means responsive to said second signal and coupled to a second of said plurality of input terminals of said third circuit means; fifth circuit means for providing a fifth signal representative of altitude above terrain of said aircraft; a limiter circuit; second gain controlled amplifier circuit means; sixth circuit means for combining a plurality of input signals including said fifth signal and a bias voltage at respective input terminals thereof and providing an output signal at an output terminal thereof, and means for coupling said output terminal, said limiter circuit and said second gain controlled amplifier circuit means in series circuit path with a third of said plurality of input terminals of said third circuit means; seventh circuit means for providing a sixth signal representative of ground velocity of said aircraft, said fifth and seventh signals coupled respectively to said first and second gain controlled amplifiers for controlling the respective gains thereof; eighth circuit means for providing a seventh signal representative of pitch rate of said aircraft; means including band pass filter circuit means coupled between said eighth circuit means and a fourth of said plurality of input terminals of said third circuit means; integrator circuit means having an input terminal and an output terminal, said output terminal coupled to a fifth of said plurality of input terminals of said third circuit means; first switching means for coupling said input terminal of said integrator circuit to said output terminal of said second circuit means for completing a series circuit path including amplifier circuit means to said system output terminal. second switching means for coupling a series circuit path including longitudinal control actuator means and control surface position sensing means between a sixth of said plurality of input terminals of said third circuit means and said system output terminal or utilization means.

Claim 10

An aircraft pitch axis control system for providing pitch axis control signals at the system output terminal thereof comprising in combination: first circuit means for providing a first signal representative of vertical acceleration of said aircraft; high pass filter circuit means responsive to said first signal for providing a second signal; second circuit means for combining a plurality of input signals at the input terminals thereof and providing an output signal at an output terminal thereof; third circuit means for providing a third signal representative of glide slope error of said aircraft; first gain controlled amplifier circuit means responsive to said third circuit means for providing a fourth signal, and means for coupling said second and fourth signals respectively to said input terminals of said second circuit means; third circuit means for combining a plurality of input signals at the input terminals thereof and providing an output signal at an output terminal thereof, and means for coupling said output terminal to said system output terminal; fourth circuit means for coupling said third signal to a first of said plurality of input terminals of said third circuit means; a first series circuit path including low pass filter circuit means responsive to said second signal and coupled to a second of said plurality of input terminals of said third circuit means; fifth circuit means for providing a fifth signal representative of altitude above terrain of said aircraft; a limiter circuit; second gain controlled amplifier circuit means; sixth circuit means for combining a plurality of input signals including said fifth signal and a bias voltage at respective input terminals thereof and providing an output signal at an output terminal thereof, and means for coupling said output terminal, said limiter circuit and said second gain controlled amplifier circuit means in series circuit path with a third of said plurality of input terminals of said third circuit means; seventh circuit means for providing a sixth signal representative of ground velocity of said aircraft, said fifth and seventh signals coupled respectively to said first and second gain controlled amplifiers for controlling the respective gains thereof; eighth circuit means for providing a seventh signal representative of pitch rate of said aircraft; means including band pass filter circuit means coupled between said eighth circuit means and a fourth of said plurality of input terminals of said third circuit means; integrator circuit means having an input terminal and an output terminal, said output terminal coupled to a fifth of said plurality of input terminals of said third circuit means; first switching means for coupling said input terminal of said integrator circuit to said output terminal of said second circuit means for completing a series circuit path including amplifier circuit means to said system output terminal. second switching means for coupling a series circuit path including longitudinal control actuator means and control surface position sensing means between a sixth of said plurality of input terminals of said third circuit means and said system output terminal or utilization means.

Claim 11

In combination in a pitch axis control system for achieving short term stability of an aircraft comprising: first means for generating a first signal representative of the change in vertical velocity of said aircraft; second means including an accelerometer disposed in said aircraft for detecting accelerations of said aircraft normal to the flight path of said aircraft and band pass filter circuit means coupled to the output of said accelerometer to provide a second signal representative of vertical acceleration of said aircraft; third means for generating a third signal representative of pitch rate of said aircraft; fourth means for combining said first, second, and third signals; and fifth means including longitudinal control actuator means coupled between said fourth means and the control surfaces of said aircraft.

Claim 12

In combination in a pitch axis control system for achieving short term stability of an aircraft comprising: first means for generating a first signal representative of the change in vertical velocity of said aircraft; second means including an accelerometer disposed in said aircraft for detecting accelerations of said aircraft normal to the flight path of said aircraft and band pass filter circuit means coupled to the output of said accelerometer to provide a second signal representative of vertical acceleration of said aircraft; third means for generating a third signal representative of pitch rate of said aircraft; fourth means for combining said first, second, and third signals; and fifth means including longitudinal control actuator means coupled between said fourth means and the control surfaces of said aircraft.

Claim 13

In combination in a pitch axis control system for causing an aircraft to track the centerline of a radio defined glide slope: first means for producing a first signal representative of the deviation of said aircraft from said glide slope; second means for generating a second signal representative of vertical acceleration of said aircraft including vertical accelerometer and high pass filter circuit coupled in series circuit; third means for combining said first signal and said second signal at the input of an integrator circuit to produce a third signal at the output of said integrator circuit representative of the change in vertical velocity of said aircraft. fourth means for producing a fourth signal representative of pitch rate of said aircraft; fifth means for combining said first, second, third, and fourth signal to null or cancel said first signal; sixth means including longitudinal control actuator means coupled between said fifth means and the control surfaces of said aircraft to cause said aircraft to track the centerline of a radio defined glide slope.

Claim 14

In combination in a pitch axis control system for causing an aircraft to track the centerline of a radio defined glide slope: first means for producing a first signal representative of the deviation of said aircraft from said glide slope; second means for generating a second signal representative of vertical acceleration of said aircraft including vertical accelerometer and high pass filter circuit coupled in series circuit; third means for combining said first signal and said second signal at the input of an integrator circuit to produce a third signal at the output of said integrator circuit representative of the change in vertical velocity of said aircraft. fourth means for producing a fourth signal representative of pitch rate of said aircraft; fifth means for combining said first, second, third, and fourth signal to null or cancel said first signal; sixth means including longitudinal control actuator means coupled between said fifth means and the control surfaces of said aircraft to cause said aircraft to track the centerline of a radio defined glide slope.

Claim 15

In combination in a pitch axis control system for an aircraft; first means for generating a first signal representative of the angular deviation from the glide slope centerline; second means including first multiplier circuit means connected in series circuit to said first means having a gain varying as a function of altitude above terrain for generating a second signal representative of distance from glide slope centerline; third means for producing a third signal including high pass filter means representative of vertical acceleration of said aircraft; fourth means for combining said second signal and said third signal at the input of an integrator circuit for producing a fourth signal at the output of said integrator circuit representative of vertical velocity of said aircraft; fifth means for generating a fifth signal representative of commanded vertical velocity of said aircraft; sixth means for combining said second signal, said fourth signal, and said fifth signal to null or cancel said second signal; seventh means including longitudinal control actuator means coupled between said sixth means and the control surfaces of said aircraft; eighth means for providing an eighth signal representative of ground velocity of said aircraft; ninth means for generating a ninth signal representative of altitude above terrain of said aircraft; first limiter circuit means connected in series circuit to said ninth means to produce a tenth signal representative of altitude above terrain of said aircraft; first limiter circuit means connected in series circuit to said ninth means to produce a tenth signal representative of commanded flight path angle of said aircraft; and second multiplier circuit means connected to said eighth signal and said tenth signal to produce said fifth signal representative of commanded vertical velocity.

Claim 16

In combination in a pitch axis control system for an aircraft; first means for generating a first signal representative of the angular deviation from the glide slope centerline; second means including first multiplier circuit means connected in series circuit to said first means having a gain varying as a function of altitude above terrain for generating a second signal representative of distance from glide slope centerline; third means for producing a third signal including high pass filter means representative of vertical acceleration of said aircraft; fourth means for combining said second signal and said third signal at the input of an integrator circuit for producing a fourth signal at the output of said integrator circuit representative of vertical velocity of said aircraft; fifth means for generating a fifth signal representative of commanded vertical velocity of said aircraft; sixth means for combining said second signal, said fourth signal, and said fifth signal to null or cancel said second signal; seventh means including longitudinal control actuator means coupled between said sixth means and the control surfaces of said aircraft; eighth means for providing an eighth signal representative of ground velocity of said aircraft; ninth means for generating a ninth signal representative of altitude above terrain of said aircraft; first limiter circuit means connected in series circuit to said ninth means to produce a tenth signal representative of altitude above terrain of said aircraft; first limiter circuit means connected in series circuit to said ninth means to produce a tenth signal representative of commanded flight path angle of said aircraft; and second multiplier circuit means connected to said eighth signal and said tenth signal to produce said fifth signal representative of commanded vertical velocity.