Method and apparatus for flight control of tiltrotor aircraft

Patent metadata

Field	Value
Publication number	US-9851723-B2
Application number	US-63169604-A
Country	US
Kind code	B2
Filing date	Jul 29, 2004
Priority date	Jul 29, 2004
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A method and apparatus provide for automatically controlling the flight of a tiltrotor aircraft while the aircraft is in flight that is at least partially rotor-borne. The method and apparatus provide for automatically tilting nacelles in response to a longitudinal-velocity control signal so as to produce a longitudinal thrust-vector component for controlling longitudinal velocity of the aircraft. Simultaneously, cyclic swashplate controls are automatically actuated so as to maintain the fuselage in a desired pitch attitude. The method and apparatus also provide for automatically actuating the cyclic swashplate controls for each rotor in response to a lateral-velocity control signal so as to produce a lateral thrust-vector component for controlling lateral velocity of the aircraft. Simultaneously, collective swashplate controls for each rotor are automatically actuated so as to maintain the fuselage in a desired roll attitude. The method and apparatus provide for yaw control through differential longitudinal thrust produced by tilting the nacelles.

First claim

The invention claimed is:

1. A method for automatically controlling the flight of a tiltrotor aircraft while the aircraft is in flight that is at least partially rotor-borne, the tiltrotor aircraft being capable of flying in a helicopter mode and in an airplane mode, the aircraft having a fuselage and at least two tiltable nacelles, each nacelle having a rotor with adjustable-pitch blades controlled by cyclic swashplate controls and collective swashplate controls, the method comprising the steps of:
providing a flight control system;
providing longitudinal swashplate controls in each nacelle;
providing lateral swashplate controls in each nacelle;
operating the tiltrotor aircraft in the helicopter flight mode while the fuselage is positioned at a level pitch attitude;
generating a longitudinal-velocity control signal based on a pilot control input for generating a longitudinal velocity while maintaining the aircraft in the helicopter flight mode;
automatically tilting the nacelles with the flight control system in response to the longitudinal-velocity control signal so as to produce a longitudinal thrust-vector component for controlling longitudinal velocity of the aircraft;
automatically actuating the longitudinal cyclic swashplate controls for each rotor with the flight control system so as to maintain the fuselage in the level pitch attitude; and
maintaining the fuselage in the level pitch attitude;
wherein each nacelle is independently tiltable;
wherein the automatically actuating the longitudinal cyclic swashplate controls for each rotor counteracts a changing in pitch attitude that would otherwise result from tilting the nacelles; and
wherein the counteracting the changing in pitch attitude occurs simultaneously with the automatically tilting the nacelles.

2. The method according to claim 1 , further comprising the steps of:
providing collective swashplate controls in each nacelle;
generating a lateral-velocity control signal;
automatically actuating the lateral cyclic swashplate controls for each rotor with the flight control system in response to the lateral-velocity control signal so as to produce a lateral thrust-vector component for controlling lateral velocity of the aircraft; and
automatically actuating the collective swashplate controls for each rotor with the flight control system so as to maintain the fuselage in a level roll attitude;
wherein the collective swashplate controls for each rotor are actuated independently from each other.

3. A method for automatically controlling the flight of a tiltrotor aircraft while the aircraft is in flight that is at least partially rotor-borne, the tiltrotor aircraft being capable of flying in a helicopter mode and in an airplane mode, the aircraft having a fuselage and at least two tiltable nacelles, each nacelle having a rotor with adjustable-pitch blades controlled by cyclic swashplate controls and collective swashplate controls, the method comprising the steps of:
providing a flight control system;
providing longitudinal swashplate controls in each nacelle;
providing lateral swashplate controls in each nacelle;
operating the tiltrotor aircraft in the helicopter flight mode while the fuselage is positioned at a level roll attitude;
generating a lateral-velocity control signal based on a pilot control input for generating a lateral velocity while maintaining the aircraft in the helicopter flight mode;
automatically actuating the lateral cyclic swashplate controls for each rotor with the flight control system in response to the lateral-velocity control signal so as to produce a lateral thrust-vector component for controlling lateral velocity of the aircraft, thereby resulting in a changing in roll attitude of the fuselage from the level roll attitude; and
automatically differentially actuating the collective swashplate controls for each rotor with the flight control system in response to the lateral-velocity control signal so as to maintain the fuselage in the level roll attitude;
wherein the collective swashplate controls for each rotor are actuated independently from each other;
wherein each nacelle is independently tiltable from each other;
wherein the automatically differentially actuating the collective swashplate controls for each rotor prevents the changing in roll attitude of the fuselage; and
wherein the preventing the changing in roll attitude occurs simultaneously with the automatically actuating the lateral cyclic swashplate.

4. The method according to claim 3 , further comprising the steps of:
generating a longitudinal-velocity control signal;
automatically tilting the nacelles with the flight control system in response to the longitudinal-velocity control signal so as to produce a longitudinal thrust-vector component for controlling longitudinal velocity of the aircraft; and
automatically actuating the longitudinal cyclic swashplate controls for each rotor with the flight control system so as to maintain the fuselage in a level pitch attitude.

5. A method for controlling a response of a tiltrotor aircraft to a wind gust while the aircraft is in flight that is at least partially rotor-borne, the tiltrotor aircraft being capable of flying in a helicopter mode and in an airplane mode, the aircraft having at least two tiltable nacelles, each nacelle having a rotor with adjustable-pitch blades controlled by cyclic swashplate controls and collective swashplate controls, the method comprising:
providing a flight control system;
providing longitudinal swashplate controls in each nacelle;
providing lateral swashplate controls in each nacelle;
operating the tiltrotor aircraft in the helicopter flight mode while the fuselage is positioned at a level pitch attitude and a level roll attitude;
automatically tilting the nacelles with the flight control system so as to produce a longitudinal thrust-vector component that opposes a longitudinal component of the wind gust while maintaining the aircraft in the helicopter flight mode;
automatically actuating the lateral cyclic swashplate controls for each rotor with the flight control system so as to produce a lateral thrust-vector component that opposes a lateral component of the wind gust and to maintain the fuselage in the level pitch attitude, thereby preventing a changing in pitch attitude of the fuselage that would otherwise result from the tilting the nacelles to produce the longitudinal thrust-vector component; and
automatically actuating the collective swashplate controls for each rotor with the flight control system so as to maintain the fuselage in the level roll attitude, thereby preventing a changing in roll attitude of the fuselage that would otherwise result from the actuating of the cyclic swashplate controls so as to produce the lateral thrust-vector component;
wherein each nacelle is independently tiltable;
wherein the wind gust is sufficient to positionally displace the tiltrotor aircraft;
wherein automatically tilting the nacelles reduces position displacement by the wind gust;
wherein automatically actuating the lateral cyclic swashplate controls reduces position displacement by the wind gust; and
wherein automatically actuating the collective swashplate controls reduces position displacement by the wind gust by differential collective control.

6. A method for automatically controlling the flight of a tiltrotor aircraft while the aircraft is in flight that is at least partially rotor-borne, the tiltrotor aircraft being capable of flying in a helicopter mode and in an airplane mode, the aircraft having only a first tiltable nacelle and a second tiltable nacelle both nacelles located on outer ends of a fixed wing, each nacelle having a rotor, the method comprising the steps of:
providing a flight control system having cyclic author

Assignees

• Builta Kenneth E
• Textron Innovations Inc

Inventors

• Builta Kenneth E

Classifications

• B64C27/52

  Tilting of rotor bodily relative to fuselage (of see-saw type construction B64C27/43) · CPC title

• B64C29/0033

  the propellers being tiltable relative to the fuselage · CPC title

• G05D1/0858 Primary

  specially adapted for vertical take-off of aircraft · CPC title