Method and system for automatically estimating at least one speed of an aircraft

Patent metadata

Field	Value
Publication number	US-9776729-B2
Application number	US-201514886727-A
Country	US
Kind code	B2
Filing date	Oct 19, 2015
Priority date	Oct 20, 2014
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A device including a first data generating unit for determining at least one aerodynamic hinge moment of at least one control surface of the aircraft, a second data generating unit for determining a plurality of data and at least one external static pressure and a model of hinge moment coefficient, a computation unit for computing with the aid of these data at least one speed of the aircraft, namely a Mach number and/or a conventional speed, and a data transmission unit for providing this speed to a user system.

First claim

The invention claimed is:

1. A method for automatically estimating at least one speed of an aircraft during flight, without using a measurement of total air pressure, the method comprising:
a) determining at least one aerodynamic hinge moment of at least one control surface of the aircraft using an existing control surface actuator or sensor onboard the aircraft;
b) determining at least the following data from the existing control surface actuator or sensor:
a static pressure external to the aircraft; and
a model of hinge moment coefficient;

c) computing a first speed of the aircraft; and
d) providing the first speed to at least one user system automatically in real time,
wherein step c) comprises computing a Mach number M representing a first speed of the aircraft, based on a relationship between the Mach number and the determined aerodynamic hinge moment in the following expression:

M
a

=

1
2

⁢
γ
⁢

⁢

P
s

⁢

M
2

⁢

V

δ
p

⁢

C
h

in which:
M a is the determined aerodynamic hinge moment;
γ is an adiabatic coefficient of the air;
P s is an external static pressure;
V δ p represents a volume of the control surface; and
C h is the model of hinge moment coefficient, dependent on the Mach number M.

2. The method of claim 1 , wherein step a) comprises sub-steps of:
measuring at least one pressure difference between two hydraulic chambers of at least one actuator intended to generate deflection of the control surface; and
computing the aerodynamic hinge moment, using at least the pressure difference.

3. The method of claim 1 , wherein step a) comprises a sub-step of directly measuring the aerodynamic hinge moment on the control surface using sources of standard data of the aircraft.

4. The method of claim 1 , wherein step c) uses a model inversion for the model of the aerodynamic hinge moment.

5. The method of claim 4 , wherein step c) implements a least squares scheme.

6. The method of claim 1 , wherein step c) uses a non-invertible function, for the model of the aerodynamic hinge moment.

7. The method of claim 6 , wherein step c) implements one of the following schemes:
a scheme using a “Least-Squares Sliding-Mode” observer;
a scheme using a “Least-Squares Luenberger” observer; and
a scheme using a “High Order Sliding-Mode” observer.

8. The method of claim 1 , wherein step b) comprises also determining at least some of the following data which are used in step c) to compute the Mach number:
at least one aerodynamic angle of the aircraft;
an angle of deflection of the at least one control surface;
at least one load factor of the control surface;
the aerodynamic configuration of the aircraft; and
at least one angular velocity of the aircraft.

9. The method of claim 1 , wherein step a) comprises determining aerodynamic hinge moments of a plurality of different control surfaces of the aircraft, and wherein step c) comprises computing the Mach number using the aerodynamic hinge moments relating to the plurality of control surfaces.

10. The method of claim 1 , which further comprises an additional step after step c), comprising computing a conventional speed representing a second speed of the aircraft, on the basis of the Mach number computed in step c) and of additional data.

11. The method of claim 1 , wherein the at least one control surface comprises at least one of an aileron, an elevator, a spoiler, a rudder, a leading edge device, and a trailing edge device.

12. A system for automatically estimating at least one speed of an aircraft during flight, without using a measurement of total air pressure, the system comprising:
a first control surface actuator or sensor of the aircraft configured to determine at least one aerodynamic hinge moment of at least one control surface of the aircraft;
a second source of standard aircraft data configured to determine at least the following data:
a static pressure external to the aircraft; and
a model of hinge moment coefficient;

computer processor configured to compute a first speed; and
at least one data transmitter configured to transmit the first speed to at least one user system,
wherein the computer processor is configured to compute a Mach number M representing a first speed of the aircraft, based on a relationship between the Mach number and the aerodynamic hinge moment in the following expression:

M
a

=

1
2

⁢
γ
⁢

⁢

P
s

⁢

M
2

⁢

V

δ
p

⁢

C
h

in which:
M a is the aerodynamic hinge moment;
γ is an adiabatic coefficient of the air;
P s is an external static pressure;
V δ p represents a volume of the control surface; and
C h is the model of hinge moment coefficient, dependent on the Mach number M.

13. The system of claim 12 , wherein the first control surface actuator or sensor comprises:
at least one measurement element configured to measure at least one pressure difference between hydraulic chambers of at least one actuator intended to generate deflection of the control surface; and
a computation element configured to compute the aerodynamic hinge moment, using at least the pressure difference.

14. The system of claim 12 , wherein the first control surface actuator or sensor comprises at least one measurement element configured to directly measure the aerodynamic hinge moment on the control surface.

15. An aircraft comprising a system according to claim 12 .

16. The system of claim 12 , wherein the at least one control surface comprises at least one of an aileron, an elevator, a spoiler, a rudder, a slat, and a flap.

Assignees

• Airbus Operations Sas

Inventors

• Goupil Philippe
• Mimmo Nicola
• Chevalier Pierre
• Lopez Fernandez Daniel
• Dayre Rémy

Classifications

• G01P21/025

  for measuring speed of fluids; for measuring speed of bodies relative to fluids (for measuring volume flow G01F25/10) · CPC title

• G01P5/02 Primary

  by measuring forces exerted by the fluid on solid bodies, e.g. anemometer · CPC title

• G01P5/14

  by measuring differences of pressure in the fluid · CPC title

• B64D43/02 Primary

  for indicating aircraft speed or stalling conditions · CPC title