Automatic approach landing and go-around pitch axis control system for aircraft

Claim 2

In a pitch axis control system having an output terminal, flare command signal voltage generating means comprising: altitude above terrain detector means; a limiter circuit, a parallel connected altitude rate circuit and altitude path displacement circuit, asymmetrical limiter circuit means, and amplifier circuit means connected in series circuit between said altitude above terrain detector means and said output terminal thereby providing a variable tangential flare point and a variable touchdown bias command as a function of time.

Claim 3

The invention according to claim 1 wherein a nose lowering command voltage is generated subsequent to touchdown for cancelling said touchdown bias command.

Claim 4

The invention according to claim 1 further comprising means for generating an automatic go-around command signal voltage in addition to said flare command signal voltage when the aircraft enters the flare region to reduce the altitude loss during the go-around maneuver.

Claim 5

A pitch axis control system for providing a flight path command signal at the system output terminal comprising in combination: glide slope error detector means; gain programmer circuit means; first adder circuit means; amplifier circuit means; said gain programmer circuit means and said first adder circuit means coupled between said glide slope error detector means and the input terminal of said amplifier means, the output terminal of said amplifier means coupled to said system output terminal; surface feedback measuring means; first means coupling said surface feedback means between the control surfaces and said system output terminal; glide slope integrator circuit means coupled between said first adder circuit means and said output terminal; altitude above terrain detector means; flare command signal generating means including asymmetrical limiter circuit means coupled between said altitude above terrain detector means and said first adder circuit means, and go-around switching means for coupling a go-around bias source to said glide slope integrator circuit.

Claim 6

A pitch axis control system for providing a flight path command signal at the system output terminal comprising in combination: glide slope error detector means; gain programmer circuit means; first adder circuit means; amplifier circuit means; said gain programmer circuit means and said first adder circuit means coupled between said glide slope error detector means and the input terminal of said amplifier means, the output terminal of said amplifier means coupled to said system output terminal; surface feedback measuring means; first means coupling said surface feedback means between the control surfaces and said system output terminal; glide slope integrator circuit means coupled between said first adder circuit means and said output terminal; altitude above terrain detector means; flare command signal generating means including asymmetrical limiter circuit means coupled between said altitude above terrain detector means and said first adder circuit means, and go-around switching means for coupling a go-around bias source to said glide slope integrator circuit.

Claim 7

The invention according to claim 4 further comprising acceleration normal to flight path detector means and altitude rate detector means coupled to said input terminal of said amplifier means.

Claim 8

The invention according to claim 5 further comprising pitch rate detector means and band pass filter means coupled in series circuit to said input terminal of said amplifier.

Claim 9

A pitch axis control system for providing a control surface error command signal at a system output terminal to position the control surfaces of an aircraft comprising in combination: glide slope detector means, gain programmer circuit means, first lag circuit means, first adder circuit means, and amplifier circuit means; said gain programmer circuit means, said first lag circuit means, and said first adder circuit means coupled in series circuit between said glide slope error detector means and the input of said amplifier circuit means, the output of said amplifier circuit means coupled to said system output terminal; control surface feedback measuring means coupled between said control surfaces and said first adder circuit means; acceleration normal to flight path detector means, second adder circuit means; said acceleration normal to flight path detector means coupled to said second adder circuit means; roll attitude detector means, versine generator means, said versine generator means coupled in series circuit between said roll attitude detector means and said second adder circuit means; first wash-out circuit means, third adder circuit means, said first wash-out circuit means coupled between said second adder circuit means and said third adder circuit means; altitude rate detector means coupled to said third adder circuit means; second lag circuit means, said second lag circuit means coupled between said third adder circuit means and said first adder means; altitude above terrain detector means, first limiter circuit means, fourth adder circuit means, said limiter circuit means coupled between said altitude above the ground detector means and said fourth adder circuit means; first series switching means coupled between said altitude above terrain detector means and said gain programmer circuit means; second wash-out circuit means coupled between said first limiter circuit means and said fourth adder circuit means; second limiter circuit means coupled between said fourth adder circuit means and said first adder circuit means; second series switching means, fifth adder circuit means, and integrator circuit means. said fifth adder circuit means and said integrator circuit means coupled in series circuit between said second series switching means and said first adder circuit means, said second series switching means connected to said system output terminal prior to system engage, and to said gain programmer circuit means during system engage; gain circuit means, sixth adder circuit means, and third series switching means, said gain circuit means and said sixth adder circuit means coupled in series circuit between the output of said integrator circuit means and said third series switching means; go-around bias circuit means coupled to said sixth adder circuit means; go-around switch means, said go-around switch means when activated causing said first switching means to reduce the output of said gain programmer circuit means to zero and further causing said third series switching means to connect the output of said sixth adder circuit means to said fifth adder circuit means.

Claim 10

A pitch axis control system for providing a control surface error command signal at a system output terminal to position the control surfaces of an aircraft comprising in combination: glide slope detector means, gain programmer circuit means, first lag circuit means, first adder circuit means, and amplifier circuit means; said gain programmer circuit means, said first lag circuit means, and said first adder circuit means coupled in series circuit between said glide slope error detector means and the input of said amplifier circuit means, the output of said amplifier circuit means coupled to said system output terminal; control surface feedback measuring means coupled between said control surfaces and said first adder circuit means; acceleration normal to flight path detector means, second adder circuit means; said acceleration normal to flight path detector means coupled to said second adder circuit means; roll attitude detector means, versine generator means, said versine generator means coupled in series circuit between said roll attitude detector means and said second adder circuit means; first wash-out circuit means, third adder circuit means, said first wash-out circuit means coupled between said second adder circuit means and said third adder circuit means; altitude rate detector means coupled to said third adder circuit means; second lag circuit means, said second lag circuit means coupled between said third adder circuit means and said first adder means; altitude above terrain detector means, first limiter circuit means, fourth adder circuit means, said limiter circuit means coupled between said altitude above the ground detector means and said fourth adder circuit means; first series switching means coupled between said altitude above terrain detector means and said gain programmer circuit means; second wash-out circuit means coupled between said first limiter circuit means and said fourth adder circuit means; second limiter circuit means coupled between said fourth adder circuit means and said first adder circuit means; second series switching means, fifth adder circuit means, and integrator circuit means. said fifth adder circuit means and said integrator circuit means coupled in series circuit between said second series switching means and said first adder circuit means, said second series switching means connected to said system output terminal prior to system engage, and to said gain programmer circuit means during system engage; gain circuit means, sixth adder circuit means, and third series switching means, said gain circuit means and said sixth adder circuit means coupled in series circuit between the output of said integrator circuit means and said third series switching means; go-around bias circuit means coupled to said sixth adder circuit means; go-around switch means, said go-around switch means when activated causing said first switching means to reduce the output of said gain programmer circuit means to zero and further causing said third series switching means to connect the output of said sixth adder circuit means to said fifth adder circuit means.

Claim 11

The invention according to claim 7 further comprising further lag circuit means coupled between said first wash-out circuit means and said first adder circuit means.

Claim 12

The invention according to claim 8 further comprising pitch rate detector means and band pass circuit means coupled in series circuit to said first adder circuit means.

Claim 13

In combination in a pitch axis control system for producing a signal representative of the flight path error of an aircraft at an output terminal during a glide slope approach and flare-out to a landing or during a go-around manuever: first means for generating a first signal representative of the altitude rate of said aircraft, said first signal referenced to tHe aircraft flight path or short period maneuvering and to the aircraft vertical rate of descent or ascent for long term manuevering; second means for selectively generating a second signal at the output of an integrator circuit representative of commanded vertical rate of descent during the approach and flare-out phase of a landing or of commanded vertical rate of ascent during the go-around phase of an approach; third means for producing a third signal above a first predetermined altitude representative of deviation from glide slope zero plane during the approach phase of a landing; fourth means for generating a fourth signal below a second predetermined altitude representative of the desired change in said commanded vertical rate of descent during the flare-out phase of a landing; fifth means for combining said third signal and said fourth signal with said first signal and said second signal to produce said flight path error signal at the output terminal.

Claim 14

In combination in a pitch axis control system for producing a signal representative of the flight path error of an aircraft at an output terminal during a glide slope approach and flare-out to a landing or during a go-around manuever: first means for generating a first signal representative of the altitude rate of said aircraft, said first signal referenced to tHe aircraft flight path or short period maneuvering and to the aircraft vertical rate of descent or ascent for long term manuevering; second means for selectively generating a second signal at the output of an integrator circuit representative of commanded vertical rate of descent during the approach and flare-out phase of a landing or of commanded vertical rate of ascent during the go-around phase of an approach; third means for producing a third signal above a first predetermined altitude representative of deviation from glide slope zero plane during the approach phase of a landing; fourth means for generating a fourth signal below a second predetermined altitude representative of the desired change in said commanded vertical rate of descent during the flare-out phase of a landing; fifth means for combining said third signal and said fourth signal with said first signal and said second signal to produce said flight path error signal at the output terminal.

Claim 15

The invention according to claim 10 further comprising sixth means including longitudinal actuator means coupled between said fifth means and the control surfaces of said aircraft.