Attitude control process and device for a spacecraft to be rotated around an axis of a body
First Claim
1. An attitude control device for a spacecraft rotatable about an axis of rotation, comprisingactuators for generating torques about said axis of rotation and two lateral axes orthogonal to each other and said axis of rotation;
- sensors for forming angular velocity signals (ω
X, ω
Y, ω
Z) with respect to the axes;
two modulators having variable dead zones, each one of said two modulators being coupled in front of said actuators assigned to one of said two lateral axes, said two modulators emitting control signals to said actuators;
two regulator networks, each one of said two regulator networks receiving an angular velocity signal for one of said lateral axes, each one of said two regulator networks furnishing a control signal for one of said two modulators, said two regulator networks having first and second paths connected in parallel, each path including two signal paths;
an integrator coupled in said second signal path;
two first multiplication elements, one of said two first multiplication elements being connected in each of said two first signal paths, said two first multiplication elements using multiplication factors proportionally dimensioned (bX, bY) to an angular velocity signal (ω
Z) of said axis of rotation;
two second multiplication elements, one of said two second multiplication elements being connected in each of said two second signal paths following said integrator, said two second multiplication elements using multiplication factors proportionally dimensioned (aX, aY) to a square (ω
Z2) of the angular velocity signal (ω
Z) of said axis of rotation; and
devices for varying the dead zone of each of said two modulators proportionally (cX, cY) to the square (ω
Z2) of the angular velocity signal of said axis of rotation.
1 Assignment
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Accused Products
Abstract
This device is used for controlling the attitude of a spacecraft to be rotated about a body'"'"'s axis of rotation. Actuators generate torques about the axis of rotation and two lateral axes. Angular velocity signals ωX, ωY with respect to the lateral axes are in each case fed to first and second signal paths. The latter contain an integrator. Modulators, which each comprise a variable dead zone, supply control signals for the actuators. In order to limit the nutation amplitude to a constant value in a reliable manner, multiplication elements are provided in the first and second signal paths. The lateral-axis angular velocity signals ωX, ωY or the angular position signals Φ, θ are acted upon by factors which are proportional to the rotation axis angular velocity signal ωZ or its square in the multiplication elements. Furthermore, the thresholds of the dead zones of the modulators are varied proportionally to ωZ2. A corresponding process for the attitude control is also described.
22 Citations
15 Claims
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1. An attitude control device for a spacecraft rotatable about an axis of rotation, comprising
actuators for generating torques about said axis of rotation and two lateral axes orthogonal to each other and said axis of rotation; -
sensors for forming angular velocity signals (ω
X, ω
Y, ω
Z) with respect to the axes;two modulators having variable dead zones, each one of said two modulators being coupled in front of said actuators assigned to one of said two lateral axes, said two modulators emitting control signals to said actuators; two regulator networks, each one of said two regulator networks receiving an angular velocity signal for one of said lateral axes, each one of said two regulator networks furnishing a control signal for one of said two modulators, said two regulator networks having first and second paths connected in parallel, each path including two signal paths; an integrator coupled in said second signal path; two first multiplication elements, one of said two first multiplication elements being connected in each of said two first signal paths, said two first multiplication elements using multiplication factors proportionally dimensioned (bX, bY) to an angular velocity signal (ω
Z) of said axis of rotation;two second multiplication elements, one of said two second multiplication elements being connected in each of said two second signal paths following said integrator, said two second multiplication elements using multiplication factors proportionally dimensioned (aX, aY) to a square (ω
Z2) of the angular velocity signal (ω
Z) of said axis of rotation; anddevices for varying the dead zone of each of said two modulators proportionally (cX, cY) to the square (ω
Z2) of the angular velocity signal of said axis of rotation. - View Dependent Claims (2, 3, 4, 5)
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6. An attitude control process for a spacecraft to be rotated about a body'"'"'s axis of rotation, said spacecraft being equipped with actuators for generating controlling torques about the axis of rotation as well as about two lateral axes orthogonal to the axis of rotation and to one another, sensors for forming angular velocity signals (ω
-
X, ω
Y, ω
Z, ) with respect to the three axes, and modulators, each provided with a variable dead zone, for emitting control signals for the actuators assigned to the lateral axes (X, Y), a first signal fraction being formed in a first signal path from each of the two lateral-axis angular velocity signals (ω
X, ω
Y); and
a second signal fraction being formed in a second signal path, said second signal path being connected in parallel to the first signal path and containing an integrator, a second signal fraction being a sum of the two signal fractions being fed to the respective modulator as a control signal, wherein the process comprises the steps of;in the two first signal paths, performing one multiplication using a factor which is proportional (bX, bY) to the rotation axis angular velocity signal (ω
Z);in the two second signal paths, performing one multiplication, following the integrator, using a factor (aX, aY) which is proportional to the square of the rotation axis angular velocity signal (ω
Z2) and;varying the thresholds of the dead zones proportionally (cX, cY) to the square of the rotation axis velocity signal (ω
Z2). - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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X, ω
Specification