Rotorcraft fly-by-wire go-around mode

Patent metadata

Field	Value
Publication number	US-10654561-B2
Application number	US-201715422886-A
Country	US
Kind code	B2
Filing date	Feb 2, 2017
Priority date	Feb 2, 2017
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

A fly-by-wire system for a rotorcraft includes a computing device having control laws. The control laws are operable to engage a level-and-climb command in response to a switch of a pilot control assembly being selected. The level-and-climb command establishes a roll-neutral (“wings level”) attitude with the rotorcraft increasing altitude. The switch may be disposed on a collective control of the pilot control assembly (e.g., a button on a grip of the collective control). Selection of the switch may correspond to a button depress. The level-and-climb command may include a roll command and a collective pitch command. One or more control laws may be further operable to increase or decrease forward airspeed in response to pilot engagement of the level-and-climb command. The level-and-climb command may correspond to a go-around maneuver, an abort maneuver, or an extreme-attitude-recovery maneuver to be performed by the rotorcraft.

First claim

What is claimed is:

1. A fly-by-wire (FBW) flight control system, comprising:
a rotorcraft flight control computer (FCC) having a control law, the control law operable to engage a level-and-climb command in response to a switch of a pilot control assembly (PCA) being selected, wherein the level-and-climb command is configured to establish a roll-neutral orientation and increase altitude; and
wherein the control law is further operable to establish the roll-neutral orientation by receiving a sensed roll orientation, the sensed roll orientation being non-neutral, and smoothly transitioning the roll orientation from the non-neutral sensed roll orientation to the roll-neutral orientation; and
further wherein smoothly transitioning the roll orientation from the non-neutral roll orientation to the roll-neutral orientation comprises filtering an initial roll angle value and a desired neutral roll angle value through a lag filter to establish a roll target and generating a roll command based upon the roll target and based upon a feedback signal.

2. The FBW flight control system of claim 1 , wherein the switch is disposed on a collective control of the PCA, and selection of the switch comprises a button depress.

3. The FBW flight control system of claim 1 , wherein the level-and-climb command comprises a roll command and a collective pitch command.

4. The FBW flight control system of claim 3 , wherein the control law is further operable to at least one of increase or decrease forward airspeed.

5. A method, comprising:
operating a rotorcraft in a first operating condition of a flight control system (FCS), the rotorcraft having a flight control computer (FCC) in electrical communication between the FCS and a pilot control assembly (PCA);
the FCC receiving a first pilot command to engage a maneuver based on selection of a switch of the PCA; and
in response to the first pilot command to engage the maneuver, the FCC transitioning to a second operating condition, wherein the second operating condition comprises the rotorcraft in a roll-neutral attitude with increasing altitude; and
wherein transitioning to a second operating condition includes (i) determining from a sensed roll angle and a desired roll angle a roll target, and (ii) based upon feedback from the rotorcraft, the roll target and pilot inputs, if any, establishing a roll command to achieve the roll-neutral attitude; and (i) linearly ramping the roll target from the sensed roll angle to the desired roll angle, or (ii) providing a fixed rate of change in roll attitude from the sensed roll angle to the desired roll angle.

6. The method of claim 5 , wherein the FCC transitioning to the second operating condition comprises:
changing a first flight characteristic, wherein changing the first flight characteristic would result in an expected change to a second flight characteristic, and wherein the first flight characteristic and the second flight characteristic have an inherently-coupled relationship;
instructing the FCS to change the first operating condition of the FCS based on the inherently-coupled relationship; and
in response to the expected change to the second flight characteristic, instructing the FCS to transition to the second operating condition of the FCS, wherein the second operating condition is operable to at least partially offset the expected change to the second flight characteristic such that the FCS is operable to at least partially decouple the inherently-coupled relationship of the first flight characteristic and the second flight characteristic.

7. The method of claim 6 , wherein at least one of:
the switch is disposed on a collective control of the PCA;
the switch comprises a button disposed on a grip of the collective control;
the method further comprises the FCC maintaining the maneuver until the rotorcraft achieves a predetermined altitude or until the FCC receives a second pilot command, the second pilot command different than the first pilot command;
the method further comprises the FCC washing out transition to the second operating condition over a duration of time;
the method further comprises the FCC determining a collective pitch angle of the second operating condition corresponding to a desired climb rate;
determination of the collective pitch angle is based on forward airspeed of the rotorcraft;

the method further comprises the FCC determining forward airspeed from at least one sensor of the rotorcraft;
the method further comprises, in response to the first pilot command to engage the maneuver, the FCC increasing or decreasing forward airspeed of the rotorcraft;
the maneuver comprises a go-around maneuver or an abort maneuver; or
the first operating condition comprises an extreme attitude of the rotorcraft.

8. A rotorcraft, comprising:
a power train coupled to a body, the power train comprising a power source and a drive shaft coupled to the power source;
a rotor system coupled to the power train and comprising a plurality of rotor blades;
a flight control system (FCS) operable to change at least one operating condition of the rotor system;
a pilot control assembly (PCA) configured to receive commands from a pilot, wherein the FCS is a fly-by-wire flight control system in electrical communication with the PCA; and
a flight control computer (FCC) in electrical communication between the FCS and the PCA, the FCC configured to:

receive, from a switch of the PCA, a first pilot command to engage a maneuver; and
in response to the first pilot command to engage the maneuver, the FCC transitioning to a second operating condition of the rotor system, wherein the second operating condition of the rotor system comprises the rotorcraft in a roll-neutral orientation and the rotorcraft increasing altitude;
wherein the FCC is further configured to establish a roll target from sensed roll angle data and from a desired roll-neutral orientation value, the roll target providing for a smooth transition from the sensed roll angle to the roll-neutral orientation; and
wherein providing for a smooth transition from the from sensed roll angle data to the roll-neutral orientation includes (i) linearly ramping a roll target from an initial value to a desired value over a specified period of time, or (ii) generating a roll target from a fixed rate of change the sensed roll angle to the roll-neutral orientation.

9. The rotorcraft of claim 8 , wherein the FCC is further configured to:
alter a first flight characteristic, wherein alteration of the first flight characteristic would result in an anticipated change to a second flight characteristic;
in response to the first pilot command to engage the maneuver, instruct the FCS to change a first operating condition of the rotor system based on a convolved relationship between the first flight characteristic and the second flight characteristic; and
in response to the anticipated change to the second flight characteristic, instruct the FCS to transition to the second operating condition of the rotor system, wherein the second operating condition of the rotor system is operable to at least partially counter the anticipated change to the second flight characteristic such that the FCS is operable to at least partially separate convolved flight characteristics.

10. The rotorcraft of claim 9 , wherein the FCC is further configured to maintain the maneuver until the rotorcraft achieves a predetermined altitude or the FCC receives a second pilot command, the second pilot command different than the first pilot command, the second pilot command received from a cyclic control of the PCA.

11. The rotorcraft of claim 10 , wherein the FCC is further configured to wash out tran

Assignees

• Textron Innovations Inc

Inventors

• Worsham Robert
• Gillett Luke Dafydd

Classifications

• B64C27/06

  with single rotor · CPC title

• B64C27/12 Primary

  Rotor drives · CPC title

• B64C27/82

  characterised by the provision of an auxiliary rotor or fluid-jet device for counter-balancing lifting rotor torque or changing direction of rotorcraft · CPC title

• G05D1/085

  to ensure coordination between different movements · CPC title

• B64C13/503 Primary

  Fly-by-Wire · CPC title