JP3281060B2 - Spacecraft unloading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unloading device for controlling the rotation of a reaction wheel for controlling the attitude of a spacecraft such as an artificial satellite.

[0002]

2. Description of the Related Art Conventionally, in a spacecraft such as an artificial satellite, a plurality of reaction wheels are used as attitude control actuators. The reaction wheel is tilted around three axes (roll (x) axis, pitch (y) axis, and yaw (z) axis) of the body of the spacecraft, for example, as shown in FIG. To place 4
Four first to fourth reaction wheels 1 to 4 such as skew wheels are arranged in a self-supporting redundant configuration,
In addition, the attitude is controlled by removing disturbances around three axes of the spacecraft body axis by the angular momentum (momentum) associated with the rotational driving of the fourth reaction wheels 1 to 4.

By the way, the first to fourth reaction wheels 1 to 4 have a limit on the number of revolutions, so that the number of revolutions called unloading is reduced to a specific value or less during driving. And remove its accumulated momentum. For this reason, the spacecraft is provided with an unloading device for controlling the rotation speed of the first to fourth reaction wheels 1 to 4. This unloading device
A well-known gas jet thruster is arranged around the body 3 axis, and the gas jet thruster is unloaded around the body 3 axis (accumulated momentum removal amount) based on the accumulated momentum of the first to fourth reaction wheels 1-4. , A torque around three axes is generated to remove each of the accumulated momentums of the first to fourth reaction wheels 1 to 4, and the rotation speed of the reaction wheels 1 to 4 is controlled.

[0004] In such an unloading device, the momentum level set to the body axis is the first.
A region A indicated by oblique lines in FIG. 4 in which none of the fourth to fourth reaction wheels 1 to 4 is saturated (the other directions are symmetrical with respect to this, but for convenience of illustration, they are shown in FIG. 4). ), And the first to fourth reaction wheels 1 to 4 are driven in this area A to remove the accumulated momentum.

The conditions under which the first to fourth reaction wheels 1 to 4 do not saturate are as follows: the momentum around the three axes of the body is H _x , H _y , H _z and the wheel accumulation capacity H _MAX is 6. 3 ^1/2 / 4 (H _x + H _y + H _z ) <6 ^Nms .. (1), for example, in the (1,1,1) direction in FIG. 3, the range is a substantially triangular pyramid indicated by B in FIG.

However, in the above-mentioned unloading device, the usable angular velocity range of the first to fourth reaction wheels 1 to 4 has a relatively wide effective range as shown in FIG. However, there is a problem that the operation must be performed using only a very narrow area A therein, and thus the operation is very troublesome.

[0007]

As described above [0005] In conventional unloading apparatus, because it is difficult to effectively use the tolerance angular speed range you reaction wheel, the operation is very troublesome Is problematic.

The present invention has been made in view of the above circumstances, and has an unloading apparatus for a spacecraft in which the angular velocity range of the reaction wheel can be effectively used to simplify the operation. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION The present invention provides four autonomously redundant reaction wheels for controlling attitude by removing disturbances around three axes of a spacecraft, namely, a roll axis, a pitch axis and a yaw axis. In a spacecraft unloading device for controlling rotation by removing accumulated momentum accompanying driving, a gas jet thruster arranged corresponding to three axes of a roll axis, a pitch axis and a yaw axis of the spacecraft is provided. An angular velocity conversion means for obtaining angular velocity data about three axes of a roll axis, a pitch axis and a yaw axis of the spacecraft from each angular velocity data of the four reaction wheels, and the spacecraft obtained by the angular velocity conversion means the angular velocity data about the pitch axis of the three axes of the angular velocity data is set as the unloading start level, as in shaft one of the roll shaft / yaw axis Choose Te, the angular velocity data
Ri and selection means for setting a start momentum, 3 from angular velocities about three axes data which has been determined by the angular velocity conversion means based on the start momentum implementation axis selected in the selection means
An unloading device for a spacecraft comprising: an unloading control unit that drives the gas jet thruster by obtaining an unloading amount around an axis and removes the accumulated momentum of the four reaction wheels. It was done.

[0010]

According to the above arrangement, one of the roll axis / yaw axis angular velocity data is selected using the angular velocity data about the pitch axis as the start level to determine the start momentum, and the unloading amount is determined based on the start momentum. This allows effective use of the usable speed range of the first and fourth reaction wheels. Therefore, the use of the first to fourth reaction wheels can be diversified, and the operation can be simplified.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an unloading apparatus for a spacecraft according to an embodiment of the present invention. 4 (see FIG. 3) is input. The output end of the machine axis conversion unit 10 is connected to a roll axis / yaw axis unloading level determination unit 11, and the roll axis / yaw axis unloading determination unit 1
The unloading control unit 12 is connected to the output terminal of the unit 1. Roll axis / yaw axis unloading determination unit 11
^{Sets the} unloading start level H _y (start level) to a margin of 0.5 ^{Nms in} consideration of the wheel control force, based on the speed data of the pitch axis based on the input speed data about the three axes of the aircraft. For example, H _y (start level) = ± ^{13.3 Nms}

A roll / yaw axis unloading rule shown in FIG.
Output to 2. Soku, the unloading law, substantially triangular region C next to the area B shown in FIG. _{4, H Y = H y +} H yM (H yM: Margin momentum)

When H _x > H _z , the start momentum is 13.8 with the execution determination axis as the roll axis.
^Nms Set to-(HY + _Hz ). When H _x <H _z , the start momentum is set to 13.8 ^Nms with the execution determination axis as the yaw axis. - Set (HY + H _x).

The output end of the body axis conversion section 10 is connected to the unloading control section 12. Based on the unloading rule from the roll axis / yaw axis unloading level determination section 12, the angular velocity data of the three axes of the body are obtained. A drive signal is generated by calculating an unloading amount around each axis, and a gas jet thruster (not shown) is driven to remove accumulated moments of the first to fourth reaction wheels 1 to 4.

Further, a wheel driving unit 13 is connected to an output end of the unloading control unit 12. The wheel drive unit 13 receives the control torque about the body 3 axis together with the drive signal from the unloading control unit 12, generates a wheel drive signal based on the drive signal and the control torque, and generates the first to fourth wheels. Reaction Wheel 1
4 is driven and controlled. The gas jet thrusters (not shown) are provided, for example, corresponding to the three axes of the spacecraft body.

As described above, the unloading device for the spacecraft includes the first to fourth reaction wheels 1
Angular velocity data around the pitch axis is obtained based on the angular velocity data of No. 4 to No. 4, and the angular velocity data around the pitch axis is used as an unloading start level to select one of the roll axis / yaw axis angular velocity data to generate a start momentum. ,
The unloading control is performed by obtaining the unloading amount around the three axes of the aircraft based on the starting momentum. According to this, by making it possible to use almost the entire area as an effective range for the first to fourth reaction usable angular speed range of the wheel 1 to 4, the first to fourth reaction The use of the wheels 1 to 4 can be diversified, and the operation can be simplified.

In the above embodiment, the case where the first to fourth reaction wheels 1 to 4 are arranged in a four-skew wheel system has been described. However, the present invention is not limited to this.
The present invention is applicable to various arrangement configurations. Therefore, it is needless to say that the present invention is not limited to the above-described embodiment, and that various modifications can be made without departing from the scope of the present invention.

[0019]

As described above in detail, according to the present invention, as it can be utilized effectively the angular velocity range of reaction wheel, Ann space vehicle which is to obtain achieving simplification of operations A loading device can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an unloading device for a spacecraft according to an embodiment of the present invention.

FIG. 2 is a diagram showing an unloading rule according to FIG. 1;

FIG. 3 is a diagram showing a state in which four reaction wheels are arranged in a self-supporting redundant configuration.

FIG. 4 is a diagram shown to explain a conventional problem.

[Explanation of symbols]

1-4 first-fourth reaction wheels, 10 ...
Airframe axis conversion unit, 11: Roll axis / yaw axis unloading level determination unit, 12: Unloading control unit, 13
... wheel drive.

Claims (1)

(57) [Claims] 1. An autonomous redundant four reaction wheel for controlling attitude by removing disturbances around three axes of a spacecraft, ie, a roll axis, a pitch axis and a yaw axis, and removing accumulated momentum accompanying driving of the reaction wheels. A space jet unloading device for controlling rotation of the spacecraft, comprising: a gas jet thruster arranged corresponding to three axes of a roll axis, a pitch axis, and a yaw axis of the spacecraft; Angular velocity conversion means for obtaining angular velocity data about three axes of the space vehicle from the angular velocity data, the roll axis, pitch axis, and yaw axis; and angular velocity data about the three axes of the spacecraft obtained by the angular velocity conversion means . Of these, the angular velocity data around the pitch axis is set as the unloading start level , and one of the roll axis and yaw axis is selected as the execution axis, and the angular velocity data is selected. Data
Selection means for setting a more starting momentum, the gas seeking the selected unloading of three axes than the angular velocities about three axes data which has been determined by the angular velocity conversion means based on the start momentum implementation axis in this selection means Driving the jet thruster, said four reactions
An unloading device for a spacecraft, comprising: unloading control means for removing wheel accumulated momentum.