Method and a system for determining an angular velocity in turning for a rotary wing aircraft

Patent metadata

Field	Value
Publication number	US-2016176522-A1
Application number	US-201514964796-A
Country	US
Kind code	A1
Filing date	Dec 10, 2015
Priority date	Dec 18, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A method and a system for determining an angular velocity in turning for a rotary wing aircraft in order to make turns that are coordinated relative to the ground or else relative to the air and in order to manage the transition between ground coordination and air coordination while taking account of the wind to which said aircraft is subjected. Said method serving to determine an angular velocity in yaw by means of an anticipation value A and a correction value B on the basis in particular of speeds of advance of the aircraft relative to the ground Va sol and relative to the air Va air , of its lateral acceleration G Y and of its lateral load factor Ny.

First claim

What is claimed is:

1 . A method of determining an angular velocity in turning for a rotary wing aircraft, the aircraft flying along a track T sol relative to the ground at a speed of advance Va, which speed of advance Va may be determined relative to the ground in order to form a speed of advance relative to the ground Va sol and relative to the air in order to form a speed of advance relative to the air Va air , a longitudinal direction X extending from the front of the aircraft to the rear of the aircraft, an elevation direction Z extending upwards perpendicularly to the longitudinal direction X, and a transverse direction Y extending from right to left perpendicularly to the longitudinal and elevation directions X and Z, the aircraft comprising:
at least one rotary wing having a plurality of blades of collective pitch and of cyclic pitch that are variable about respective pitch axes, the aircraft being capable of performing movements in rotation about the directions and in translation along the directions; and an autopilot for generating control signals in compliance with predefined modes of operation and in compliance with flight setpoints, the control signals being capable of causing the aircraft to form the movements in rotation and/or translation relative to the directions; the method including the following steps: determining a longitudinal speed V Long for use in determining an anticipation value A for an angular velocity in yaw of the aircraft to apply during a turn, such that:
the longitudinal speed V Long is equal to a longitudinal speed of advance relative to the ground (Va sol ) Long such that V Long =(Va sol ) Long when the longitudinal speed of advance relative to the ground lies strictly within a first interval Int1 centered on a longitudinal speed of advance relative to the ground (Va air ) Long and of width D int1 ;
the longitudinal speed V Long is equal to a high first boundary of the first interval Int1 when the longitudinal speed of advance relative to the ground (Va sol ) Long is greater than or equal to the high first boundary, the high first boundary being equal to the longitudinal speed of advance relative to the air (Va air ) Long plus a margin Offset equal to half of the width D int1 , such that:

Offset
=

D

int



1

2

and

V
Long

=

(

Va
air

)

Long

+

D

int



1

2

the longitudinal speed V Long is equal to a low first boundary of the first interval Int1 when the longitudinal speed of advance relative to the ground (Va sol ) Long is less than or equal to the low first boundary, the low first boundary being equal to the longitudinal speed of advance relative to the air (Va air ) Long minus the margin Offset such that:

V
Long

=

(

Va
air

)

Long

-

D

int



1

2

determining the anticipation value A for the angular velocity in yaw ( ) such that:

A
=

G
Y

V
Long

where G Y is a lateral acceleration of the aircraft under the control of a pilot of the aircraft;
determining a lateral speed V Lat for use in determining a correction value B of the angular velocity in yaw for application during the turn, such that:
the lateral speed V Lat is equal to a lateral speed of advance relative to the ground (Va sol ) Lat such that V Lat =(Va sol ) Lat when the lateral speed of advance relative to the ground (Va sol ) Lat lies strictly within a second interval Int2 bounded firstly by a low second boundary equal to a first product of a first multiplier coefficient K 1 multiplied by a lateral load factor Ny of the aircraft minus a low margin Offset Lo , and secondly by a high boundary equal to the first product plus a high margin Offset Hi ;
the lateral speed V Lat is equal to the high second boundary when the lateral speed of advance relative to the ground (Va sol ) Lat is greater than or equal to the high second boundary, such that:
V Lat =K 1 ×Ny +Offset Hi

the lateral speed V Lat is equal to the low second boundary when the lateral speed of advance relative to the ground (Va sol ) Lat is less than or equal to the low second boundary, such that:
V Lat =K 1 ×Ny −Offset Lo

determining the correction value B for the angular velocity in yaw such that:
B=K 2 ×V Lat

K 2 being a second multiplier coefficient; and
determining the angular velocity in yaw so as to follow the track T sol in the turn, such that:
= A+B

2 . A method according to claim 1 , for determining an angular velocity in turning for a rotary wing aircraft, wherein the margin Offset, the high margin Offset Hi , and the low margin Offset Lo are variable and decrease when the speed of advance relative to the air Va air increases.

3 . A method according to claim 1 , for determining an angular velocity in turning for a rotary wing aircraft, wherein the value Offset is equal to 20 kt when the speed of advance relative to the air Va air is less than 20 kt.

4 . A method according to claim 1 , for determining an angular velocity in turning for a rotary wing aircraft, wherein the high margin Offset Hi and low margin Offset Lo are equal respectively to +20 kt and −20 kt when the speed of advance relative to the air Va air is less than 20 kt.

5 . A method according to claim 1 , for determining an angular velocity in turning for a rotary wing aircraft, wherein the margin Offset, the high margin Offset Hi , and the low margin Offset Lo are zero when the speed of advance relative to the air Va air , is greater than or equal to 70 k

Assignees

• Airbus Helicopters

Inventors

• Salesse-Lavergne Marc

Classifications

• G01P5/00

  Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft (application of speed-measuring devices for measuring volume of fluid G01F) · CPC title

• G05D1/0858

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

• G05D1/0808

  specially adapted for aircraft · CPC title

• B64C27/57 Primary

  automatic or condition responsive, e.g. responsive to rotor speed, torque or thrust · CPC title

• G05D1/0204 Primary

  to counteract a sudden perturbation, e.g. cross-wind, gust · CPC title