JPS5836798A - Controller for attitude of satellite - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a satellite attitude control device using an attitude control reactor wheel mounted on an artificial satellite.

For example, three-axis attitude control satellites often use reactor wheels as their attitude control actuators. That is, the attitude of the satellite varies due to disturbance torque acting on the satellite body, and the rotational moment of the satellite body fluctuates, resulting in a satellite attitude error. The attitude error is detected by a sensor or the like, and based on this detection signal, an attitude control logic section generates a wheel drive signal, and this drive signal controls increasing/decreasing of the rotational speed of the reaction wheel. At this time, the satellite attitude error is corrected by the reaction torque generated in the reaction wheel.

In other words, the rotational component F of the satellite main body caused by the disturbance torque is absorbed by the rotating cage of the reaction wheel, and the rotation of the satellite main body is brought to zero to maintain the attitude of the satellite.

Figure 1 shows the schematic structure of a conventional reactor wheel, in which a rotor 1 is rotatably attached to a shaft 3 via a pairing 2, and a stator (not shown) is attached to the rotor 1. It is designed to be driven by supplying an excitation signal (drive signal) to.

As a conventional example of a drive device for driving a rear axle and a wheel with a single rear axle and a wheel, a single rear axle and a wheel system is shown in FIG. Satellite attitude 1. The rate varies depending on the disturbance torque, and the sensor 21 detects the above attitude and rate. The attitude control logic section 22 generates a wheel drive signal based on the detection signal of the sensor 21, and drives one reaction wheel 23. This increases or decreases the rotation of the wheel's rotor, and the reaction torque generated at that time controls the satellite's attitude. In other words, the rotor absorbs the rotational moment of the satellite body, thereby maintaining the satellite attitude error at zero.

However, since the polarity of disturbance torque and the like acting on the satellite is not always constant, there are cases where the rotation of the wheel rotor is reversed (called a zero cross). At this zero cross,
The disadvantage is that a stationary band is created due to the solid friction of the bearings interposed between the rotor and the shaft, which prevents the rotor from rotating smoothly and causes the satellite attitude to fluctuate.

On the other hand, Fig. 3 shows two scanning wheels 31°S2.
Detection of posture errors and moxibustion force control using
A conventional example of a rear-wheel drive system is shown below.
The attitude control logic unit 33 generates ←) a drive signal or a 0 drive signal, (←) accelerates the rotor according to the drive signal, ←) decelerates the rotor, and (c) generates a drive signal ←).
The rotor is decelerated and the 0 rotor is accelerated.

However, in the device of FIG. 3, each wheel 11.81
Since both have the function of a senna, they can only rotate in one direction, and the rotor rotation speed cannot be lowered below the specified value.
Therefore, even though two wheels are mounted, the amount of rotational moment of the satellite body that can be absorbed by the two wheels is small, resulting in poor efficiency.

The present invention has been made to eliminate the above-mentioned drawbacks, and consists of a single rear axle having two coaxially arranged rotors;
By driving each rotor of the wheel separately,
An object of the present invention is to provide a satellite attitude control device that can prevent the occurrence of wheel zero crossings and improve the accuracy of satellite attitude control.

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

FIG. 4 shows a schematic structure of a rear axle wheel used in the present invention, in which an inner rotor 43 is arranged around a shaft 410 via an inner bearing 42, and an outer bearing 44 is arranged around the outer periphery of the inner rotor 43. By disposing the outer rotor 45 through the outer rotor 4, both rotors 4
B and 4B can be rotated independently. In other words, both rotors 43 and 45 are provided coaxially with respect to the shaft 41.

5(a) and 5(b) show the basic structure of the above-mentioned wheel, and the same parts as in FIG. 4 are given the same reference numerals. An inner stator is supplied with a drive signal, 41 is an acter stator to which an outer drive signal is supplied to drive the outer rotor 45, and 48 is a case.

FIG. 6 shows an example of a satellite attitude control device according to the present invention, in which a sensor 21 measures the satellite attitude.

The attitude control logic section e1 detects the rate and outputs a sensor signal, and generates an inch drive signal and an outer drive signal based on the sensor signal.

Inner rotor 48. The rotation range of both the actor rotor 45 is -1500~+150Orpm around the reference rotation speed.
The operation will be explained assuming that (,) in a steady state.

Inner rotor 41 -1 Orpm e Outer rotor 45
is driven to rotate at +1 Orpm.

伽) If the wheel absorbs the momentum of (→) due to attitude and rate errors.

Say? Based on the signal, the control logic unit 61 generates the actor drive signal ←), and increases the actor drive signal by +150 Or
pm Increase speed in O direction. At this time, the inner rotor 4 J
a Maintain rotation at 10 rpm.

(@) When the wheel absorbs 00 momentum.

The control logic unit 61 generates an inner drive signal of 0, and subsequently generates an outer drive signal of 0. Therefore, the inner number 43. The speed of both the outer rotor 45 is increased in the (towards) direction.

However, if the moment of inertia of the inner rotor 43 is designed to be smaller than that of the outer rotor 45, the inner rotor 43
Since the change in the rotation speed of the outer rotor 45 is faster than the change in the rotation speed of the outer rotor 45, the rotation speed of the outer rotor 45 and the rotation speed of the inner rotor 43 do not match before reaching 1500 rpm.

Therefore, the inner rotor 43. The relative speed between the actor rotors 45 rarely becomes zero, and zero crossing can be prevented from occurring. .

Inner rotor 43 in the process of (,), (b), (@) mentioned above. Changes in the rotational speed between the outer rotor 45 are shown in FIGS. 7(a), (b), and (c).

That is, in the above embodiment, the control logic unit 61 generates an inner drive signal and an outer drive signal that satisfy the following conditions.

Inner rotor rotational speed<-IQrpm Actor rotor rotational speed>Inner rotor rotational speed The numerical values in the above embodiment are merely examples, and the wheel control by the control i4I logic unit #1 is not limited to the above embodiment.

As described above, according to the present invention, one reactor having two coaxially arranged rotors, each rotor of a wheel is controlled by the relative rotational speed between the shaft and the inner rotor and the relative rotational speed between the inner rotor and the outer rotor. It is driven so that the relative rotational speed does not become zero. This prevents the occurrence of zero crosses, prevents fluctuations in the satellite attitude and rate caused by zero crosses, and enables highly accurate satellite attitude control. A possible satellite attitude control device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a conventional satellite attitude control rear axis/wheel, FIGS. 2 and 3 are configuration explanatory diagrams showing different examples of conventional satellite attitude control devices, and FIG. 4 is a schematic configuration diagram showing a conventional satellite attitude control system. A schematic configuration diagram showing the reactor wheels used,
Figure 5(a). (b) is a partially cutaway perspective view and a vertical cross-sectional view schematically showing the basic structure of the wheel shown in FIG. 4, and FIG. Figure 7 (
, ) , (b) , (,) are diagrams showing the rotation speed change characteristics of each rotor in the apparatus of FIG. 6. 41.-Shaft, 4S-Inner rotor, 45.. Actor rotor, 61.-Attitude control Rosic section. Figure 2

Claims (1)

[Claims] An axis wheel for attitude control is provided with an inner rotor and an outer rotor coaxially with respect to the shirt, and the axis wheel is mounted on the satellite together with this wheel to detect the satellite's attitude, etc. and an attitude control p-sick section that drives each rotor based on a signal so that the relative rotational speed between the shear 7F and the inner rotor and the relative rotational speed between the inner rotor and the outer rotor do not become zero. A satellite attitude control device characterized by: