Method and device for controlling attitude of a spacecraft

Patent metadata

Field	Value
Publication number	US-2018072435-A1
Application number	US-201615563271-A
Country	US
Kind code	A1
Filing date	Mar 31, 2016
Priority date	Mar 31, 2015
Publication date	Mar 15, 2018
Grant date	—

Abstract

A method of controlling the attitude of a spacecraft in spinning around itself with a non-zero total angular momentum H TOT . The spacecraft includes a set of inertia flywheels configured to form an internal angular momentum H ACT . The axis of the total angular momentum H TOT is aligned with a principal axis of inertia of the spacecraft, in the course of which the inertia flywheels are controlled to form an internal angular momentum H ACT . The following expression, in which J is the inertia matrix of the spacecraft:
H act ×J −1 ( H tot J −1 H tot )
is negative if the principal axis of inertia targeted is the axis of maximum inertia of the spacecraft and is positive if the principal axis inertia targeted is the axis of minimum inertia of the spacecraft.

First claim

1 - 10 . (canceled)

11 . An attitude control method for a spacecraft rotating on itself with a non-zero total angular momentum H tot , the spacecraft comprising a set of inertia flywheels configured to form an internal angular momentum H act of any axis in a craft reference frame, the method comprising steps of:
aligning an axis of the total angular momentum H tot with a principal axis of inertia of the spacecraft; controlling the inertia flywheels, during the aligning step, so as to form an internal angular momentum H act such that a following expression:
H act ×J −1 ( H tot J −1 H tot )

is negative throughout the duration of the aligning step if a targeted principal axis of inertia is an axis of maximum inertia of the spacecraft, and is positive throughout the duration of the aligning step if the targeted principal axis of inertia is an axis of minimum inertia of the spacecraft;
wherein J in the expression is an inertia matrix of the spacecraft, an operator × is a scalar product between two vectors and an operator is a vector product between two vectors; and
wherein the inertia flywheels are controlled so as to form the internal angular momentum H act for which an angle θ between the internal angular momentum H act and the vector J −1 (H tot J −1 H tot ) bears out, throughout the duration of the aligning step, a following expression: |cos θ|>0.9.

12 . The method as claimed in claim 11 , wherein the inertia flywheels are controlled, throughout the duration of the step of aligning the principal axis of inertia, so as to form the internal angular momentum H act :
H act =K V ·U
Expression wherein K V is a scalar parameter that is negative if the targeted principal axis of inertia is the axis of maximum inertia of the spacecraft or is positive if the targeted principal axis of inertia is the axis of minimum inertia of the spacecraft, and U corresponds to a unitary vector:

U
=

J

-
1



(

H
tot

⊗

J

-
1



H
tot

)



J

-
1



(

H
tot

⊗

J

-
1



H
tot

)



.

13 . The method as claimed in claim 11 , further comprising, after the step of aligning with the principal axis of inertia, a step of aligning a predetermined axis X in the craft reference frame, during which the inertia flywheels are controlled so as to lock components of the internal angular momentum H act according to the axes Y, Z, transverse to the axis X, on to setpoints respectively h Y and h Z determined as a function of components of a speed of rotation of the spacecraft according to the axes Y, Z;
wherein the setpoint h Y of the internal angular momentum H act according to the axis Y is determined according to a control law of proportional-integral type from a component r of the speed of rotation according to the axis Z; and wherein the setpoint h Z of the internal angular momentum H act according to the axis Z is determined according to the control law of proportional-integral type from a component q of the speed of rotation according to the axis Y.

14 . The method as claimed in claim 13 , wherein the setpoints h Y and h Z of the internal angular momentum H act according to the axes Y and Z, respectively, are linked to the components r and q, respectively, of the speed of rotation by a following transfer functions, expressed in a Laplace domain:

{

h
Y

=

K
Z



(

1
+

ω
Z

s

)


r

h
Z

=

-

K
Y



(

1
+

ω
Y

s

)



Assignees

• Airbus Defence & Space Sas

Inventors

• Cuilleron Nicolas
• Laurens Philippe
• Moro Valerio

Classifications

• B64G1/286

  using control momentum gyroscopes (CMGs) · CPC title

• B64G1/283 Primary

  using reaction wheels · CPC title

• B64G1/244 Primary

  Spacecraft control systems · CPC title

• B64G1/26

  using jets · CPC title

• G05D1/0883

  Physics · mapped topic