JPH0442239B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the three-axis attitude of an artificial satellite using wheels, and particularly to a device for suppressing disturbances in the attitude of an artificial satellite during unloading.

Conventionally, as a so-called unloading method to release excess angular momentum accumulated in the wheel, angular momentum equivalent to the excess angular momentum of the wheel is applied to the satellite by a thruster or magnetic torquer, etc., and the angle given to the satellite is This is typically accomplished by the wheels absorbing the motion. A conventional example of this type of device is the one shown in FIG. In the figure, 1 is a sensor that detects the attitude of the satellite, 2 is a control circuit, 3 is a wheel, and 4 is an unloading circuit that determines and executes unloading based on the number of rotations of the wheel, etc. An unloading circuit 5 generates torque for unloading. magnetic torquer (or thruster) as an actuator to
shows the functional parts of the satellite's motion. The portion indicated by dotted lines in the figure is due to the motion of the wheels and the satellite, and the solid line indicates the flow of signals within the device. Next, the operation of the configuration shown in FIG. 1 will be explained. A sensor 1 detects the attitude of the satellite, and a control circuit 2 drives a wheel 3 based on the signal. The driven wheel generates torque by changing its rotational speed (or angular momentum), giving motion 6 to the satellite in the direction of arrow dotted line A.
Therefore, the wheel works to control the attitude of the satellite detected by the sensor 1. If such a satellite is controlled continuously, the wheel rotation speed (angular momentum) will deviate from the range normally used.
It becomes necessary to perform so-called unloading to return the value to within that range. Therefore, the unloading circuit 4 determines whether or not to perform unloading based on the number of rotations of the wheel, and if unloading is necessary, a magnetic torquer (or thruster) 5 applies torque to the satellite, causing the satellite to move. 6, the angular momentum corresponding to the torque generated is transferred to the wheel in the direction of the arrow dotted line B, and the rotation speed (angular momentum) of the wheel is returned to the normally used range. By the way, in conventional devices like this, when unloading, the satellite's attitude is disturbed because it gives angular momentum to the satellite and then returns the angular momentum of the wheels, which deteriorates the attitude control accuracy of the satellite and causes problems in the case of unloading. In some cases, the satellite mission has to be interrupted during unloading.

This invention was made to eliminate these drawbacks, and proposes an attitude control device for an artificial satellite configured to prevent disturbances in attitude control during unloading.

An embodiment of the present invention shown in FIG. 2 will be described below. Note that 1 to 6 in the figure are the same as those shown in FIG. The difference from FIG. 1 is that the output of the unloading circuit 4 is applied to the wheel 3 along the route indicated by the solid arrow C.

In other words, the unloading circuit 4 supplies a signal to the magnetic torquer (or thruster) 5 to generate a torque for unloading, but at the same time, the unloading circuit 4 supplies the magnetic torquer (or thruster) 5 with a signal that generates a torque for unloading. supply a signal to. By applying the signal of the unloading circuit 4 to the wheel 3 in this way, it is possible to reduce the attitude disturbance during unloading, which is the case in the conventional case of imparting angular momentum to the satellite and releasing the excess angular momentum of the wheel. I can do it.
In other words, if you directly apply an electrical signal to the wheel that is equivalent to the angular momentum that unloads the wheel, the angular momentum released by the wheel and the magnetic torquer (or thruster) will simultaneously unload the wheel. Since the angular momentum given to the satellite by 5 acts almost simultaneously on the satellite's motion 6, the angular momentum generated in the satellite, which was a factor that disturbed the satellite's attitude in conventional devices, is canceled out, and the attitude of the satellite is changed. There will be less turbulence.

From the above explanation, it can be seen that by applying the unloading signal directly to the wheel, it is possible to easily reduce the disturbance in the posture during unloading.

The embodiment shown in FIG. 2 is an example of the use of this invention, and the apparatus that can embody this invention is not limited to the example shown here.
It is also applicable to any device in which unloading can be achieved by simultaneously controlling the actuator to be unloaded (e.g. a wheel, etc.) and the actuator for removing its angular momentum (e.g. magnetic torquer, thruster, etc.) .

In addition, although wheels, magnetic torquers, and thrusters are used as examples of actuators in this example, it is in principle possible to apply this invention to all actuators used in other artificial satellites (e.g., ion engines, etc.). It is also clear that

As described above, the present invention has the advantage that disturbances in the attitude during unloading can be reduced, and the mission of the satellite during unloading can be sufficiently accomplished without interrupting the mission.

This invention is particularly effective in devices in which unloading is achieved by generating torque in a pulsed manner using a thruster, magnetic torquer, or the like, since disturbances in the attitude of the satellite become large.

[Brief explanation of drawings]

FIG. 1 is a block explanatory diagram showing an example of a conventional attitude control device, and FIG. 2 is a block explanatory diagram showing an attitude control device according to the present invention.
2 is a sensor, 2 is a control circuit, 3 is a wheel, 4 is an unloading circuit, 5 is a magnetic torquer (or thruster), and 6 is a functional part for the movement of the satellite. It should be noted that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. An attitude control device for an artificial satellite that controls the attitude of an artificial satellite in three axes, comprising: a sensor that detects the attitude of the satellite; a wheel that generates torque to give motion to the satellite; a control circuit that drives the wheel based on an output signal; an actuator that provides a torque for unloading to the satellite; and a signal that generates a torque for unloading to the actuator;
An attitude control device for an artificial satellite, comprising: an unloading circuit that supplies an electrical signal to the wheel so that the wheel generates a torque corresponding to the torque applied to the satellite by the actuator.