Systems and methods for energy managed autoflight guidance using potential flight path angle

Patent metadata

Field	Value
Publication number	US-12055950-B2
Application number	US-202016990780-A
Country	US
Kind code	B2
Filing date	Aug 11, 2020
Priority date	Sep 16, 2019
Publication date	Aug 6, 2024
Grant date	Aug 6, 2024

Abstract

Systems and methods for an energy managed autoflight function that enables maneuvers previously done by the speed-on-elevator modes to be achieved while maintaining the autoflight function in speed-on-throttle mode. An autoflight guidance algorithm and strategy replaces speed-on-elevator modes with an automatic flight path angle (Auto-FPA) mode that can control speed-controlled climbs and descents. The autoflight guidance algorithm and strategy provide (i) autothrust and autoflight coordination during speed-on-throttle modes, (ii) and Auto-FPA control law or mode, (iii) the Auto-FPA control law being configurable for fixed thrust modes, and (iv) a speed protection monitoring scheme.

First claim

The invention claimed is:

1. A flight control system on an aircraft having an autoflight and autothrust system for receiving and processing a target airspeed and autoflight control mode inputs to automatically manage energy by coordinating autoflight target and autothrust system commands, the system comprising a speed envelope monitor and a control module, the control module including a processor configured by programming instructions on non-transient computer readable media, the control module configured to:
receive a potential flight path angle target (tFPA) from the autothrust system that is based on the target airspeed;
receive a vertical target from the autoflight system (rFPA) that is based on the autoflight control mode inputs, the autoflight control mode inputs including a mode selection;
generate a potential flight path angle command (PFPAcmd) for use as an active autothrust command based on the rFPA and tFPA;
generate an FPA command (FPAcmd) for use as the active autoflight target based on the rFPA; and
present the rFPA and the PFPAcmd on a primary flight display;

the speed envelope monitor configured to:
predict a time to zero acceleration based on maintaining the aircraft inside an existing aircraft speed envelope limit; and
based on the time to zero acceleration, (i) request activation of the autothrust when it is not activated, (ii) request activation of an auto-FPA mode when it is not active, and (iii) request auto-pilot activation when it is not active.

2. The flight control system of claim 1 , wherein the control module is further configured to display filter the rFPA prior to generating the potential flight path angle command (PFPAcmd).

3. The flight control system of claim 1 , wherein the control module is further configured to:
generate the flight path angle command (FPAcmd) further as a modification of the rFPA with the tFPA, thereby activating an auto-FPA mode; and
display filter the modification of the rFPA with the tFPA prior to generating the potential flight path angle command (PFPAcmd).

4. The flight control system of claim 1 , wherein the control module is further configured to:
perform acceleration limiting on the modification of the rFPA with the tFPA prior to performing the display filter, the acceleration limiting being based on available energy, wherein the available energy is represented by predicted potential flight path angle (PPFPA) limits.

5. The flight control system of claim 4 , further comprising a speed envelop monitor configured to determine whether the PFPAcmd exceeds the PPFPA limits; and
wherein the control module is further configured to:
update the rFPA to thereby maintain the autothrust system in a speed-on-throttle mode when the PFPAcmd does not exceed the PPFPA limits;
and
display filter a modification of the updated rFPA with the tFPA prior to generating the potential flight path angle command (PFPAcmd).

6. The flight control system of claim 1 , wherein the control module is further configured to:
receive a user input requesting a climb or descent;
activate an auto-FPA mode responsive to the requested climb or descent;
utilize a minimum predicted potential flight path angle (min PPFPA) or a maximum predicted potential flight path angle (max PPFPA) as the rFPA, based on the climb or descent request; and
generate the flight path angle command (FPAcmd) further based on the rFPA, the tFPA, and either the min PPFPA or the max PPFPA.

7. The flight control system of claim 6 , wherein the control module is further configured to modify the rFPA with a scaling factor to provide a margin for bi-directional speed-on-throttle control during the climb or descent.

8. The flight control system of claim 7 , wherein the scaling factor is less than 100% and the control module, in an auto-FPA mode, generates commands for autothrottle and autopilot based on blending the PFPA and FPA.

9. The flight control system of claim 8 , wherein the control module, in auto-FPA mode, determines a speed range for the aircraft based on the scaling factor.

10. A method for energy managed flight control on an aircraft having an autoflight and autothrust system, the method comprising:
receiving a target airspeed and autoflight control mode inputs including a mode selection;
receiving a potential flight path angle target (tFPA) from the autothrust system that is based on the target airspeed;
receiving a vertical target from the autoflight system (rFPA) that is based on the autoflight control mode inputs;
generate a potential flight path angle command (PFPAcmd) for use as an active autothrust command based on the rFPA and tFPA;
generate an FPA command (FPAcmd) for use as the active autoflight target based on the rFPA;
present the rFPA and the PFPAcmd on a primary flight display;
predicting, by a speed envelope monitor, a time to zero acceleration based on maintaining the aircraft inside an existing aircraft speed envelope limit; and
based on the time to zero acceleration, (i) requesting activation of the autothrust when it is not activated, (ii) request activation of an auto-FPA mode when it is not active, (iii) request auto-pilot activation when it is not active, and (iv) request other speed protection mechanisms.

11. The method of claim 10 , further comprising display filtering the rFPA prior to generating the potential flight path angle command (PFPAcmd).

12. The method of claim 10 , further comprising:
generating the flight path angle command (FPAcmd) further as a modification of the rFPA with the tFPA, thereby activating an auto-FPA mode; and
display filtering the modification of the rFPA with the tFPA prior to generating the potential flight path angle command (PFPAcmd).

13. The method of claim 10 , further comprising:
performing acceleration limiting on the modification of the rFPA with the tFPA prior to performing the display filtering; wherein
the acceleration limiting is based on available energy, represented by predicted potential flight path angle (PPFPA) limits.

14. The method of claim 13 , further comprising:
determining, at a speed envelope monitor, whether the PFPAcmd exceeds the PPFPA limits; and
updating the rFPA to thereby maintain the autothrust system in a speed-on-throttle mode when the PFPAcmd does not exceed the PPFPA limits;
and
display filtering a modification of the updated rFPA with the tFPA prior to generating the potential flight path angle command (PFPAcmd).

15. The method of claim 10 , further comprising:
receiving a user input requesting a climb or descent;
activating an auto-FPA mode responsive to the requested climb or descent;
utilizing a minimum predicted potential flight path angle (min PPFPA) or a maximum predicted potential flight path angle (max PPFPA) as the rFPA, based on the climb or descent request; and
generating the flight path angle command (FPAcmd) further based on the rFPA, the tFPA, and either the min PPFPA or the max PPFPA.

16. The method of claim 15 , further comprising: modifying the rFPA with a scaling factor to provide a margin for bi-directional speed-on-throttle control during the climb or descent.

17. The method of claim 16 , further comprising:
activating auto-FPA mode when the scaling factor is less than 100%; and
generating commands for autothrottle and autopilot based on blending the PFPA and FPA.

18. The method of claim 17 , further comprising determining a speed range for the aircraft based on the scaling factor.

19. A flight control system on an aircraft having an autoflight and autothrust sy

Assignees

• Honeywell Int Inc

Inventors

• Melendez Luis
• Sin Philip
• Koenig John

Classifications

• G05D1/46

  Control of position or course in three dimensions [3D] · CPC title

• B64D31/08

  for keeping cruising speed constant · CPC title

• G05D1/49 Primary

  Control of attitude, i.e. control of roll, pitch or yaw · CPC title

• G05D1/0607 Primary

  specially adapted for aircraft · CPC title

• G05D1/0638 Primary

  by combined action on the pitch and on the motors · CPC title