JPS59112703A - Antenna driver - Google Patents

Abstract

PURPOSE:To eliminate a mechanical friction part in antenna expansion and in fine adjustment driving and to eliminate a backlash by inserting an antenna reflection mirror into a fixed shaft in a noncontacting float state magnetically by a magnetic float body. CONSTITUTION:The antenna reflection mirror 2 is supported by a supporting metallic fixture 9 projecting from the magnetic float body 10 inserted into the fixed shaft 8 fixed to a satellite body 1 in the noncontacting float state. An electromagnetic actuator 19 is fitted to the satellite body 1, and a control piece 20 faces the actuator 19 when the antenna reflection mirror 2 fitted to the magnetic float body 10 is expanded and is made of a permanent magnet entirely or fitted with a permanent magnet on the facing side of the actuator 19 to generate mutually separating resiliency as to the actuator 19, thereby performing control while the resulting force of rotation is opposed to that by a spring 17. Consequently, there is no mechanical friction part in antenna expansion and in fine adjustment driving and any backlash is not caused.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna driving device mounted on an artificial satellite.

A typical three-axis stabilized geostationary d-satellite is shown in Figure 1. That is, 1 is a satellite main body, 2 is an antenna reflector, 3 is an antenna drive device, 4 is a primary radiator, and 5 is a Norabador. At the time of launch, the antenna reflector 2 is folded into the satellite main body as shown by the chain line in the figure, and the reflector is expanded by the antenna drive device 3 on the geostationary orbit, and the antenna pointing direction is directed towards the earth direction 6. The driving source for deployment generally uses a spring. Conventional antenna drive device 3
The friction of the rotating friction part is reduced by using a fixed lubricant, but since the weakest spring is used to reduce the impact when deployed, there are problems such as the rotating part getting caught in the middle and not being able to deploy. Sometimes it occurred. In addition, when controlling the antenna pointing direction with high precision, a step motor and a reduction gear are used to minutely drive the angle of the antenna reflector in order to add a function to the antenna drive device that changes the pointing direction minutely. There is.

However, in the future, antenna pointing accuracy of about 0.01 de9 and guarantee of long-term use of over 1000 years will be required.
In a vacuum, where there are many unknown points, lubrication of rotating friction parts and lubrication of gear parts become problems.

In view of the above-mentioned points, the present invention provides an antenna driving device mounted on an artificial satellite that does not include a mechanical friction part and is free from bumps.The present invention will be described in detail below.

FIG. 2 shows an embodiment of the present invention, parts corresponding to those shown in FIG. As shown in FIG. 1, this is a magnetically levitated body inserted into a fixed shaft 8, and an antenna reflector is supported by a support fitting 9 protruding from this levitated body 10.

11 is a permanent magnet on the fixed shaft side, and 12 is a permanent magnet on the floating body side. Both permanent magnets 11 and 12 are magnetized so as to attract each other in the axial direction of the rotating shaft 8.

As a result, when the fixed shaft 8 and the magnetically levitated body 10 become eccentric,
A component force in the radial direction acts to eliminate the eccentricity, keeping both parts concentric at all times, increasing the rigidity of the air bearing. Reference numeral 13 denotes a control electromagnetic section, which is controlled by current adjustment so that the distance between the opposing floating body flange 14 is always kept constant by a signal from a distance detecting device such as a sensor.

] 5 is a bearing, which prevents the permanent magnet 12 on the magnetically levitated body side and the permanent magnet 11 on the fixed shaft side from coming into close contact with each other when power cannot be supplied to the control electromagnetic part 13, and after the satellite is launched. The role is finished. Reference numeral 16 denotes a retaining fitting attached to the satellite body 1, and this retaining fitting fixes one end of the spring 17. An elastic string 18 is connected to the other end of the spring 17, and the elastic string 18 is wrapped around the magnetically levitated body 10 and the end is fixed, and the spring 17 serves as a driving source when the antenna reflector is deployed. . 19 is an electromagnetic actuator attached to the satellite body 1, and 20 is a control piece that is attached to the magnetically levitated body 1o and faces the actuator 19 when the antenna reflector is deployed. A magnet is attached so that a magnetic repulsion force is exerted between the electromagnetic actuator material and the actuator material to separate them from each other, and the rotational force generated by the magnet is opposed to the rotational force generated by the spring 17 for control. do.

FIG. 4 shows the state of the antenna reflector of the device of the present invention before and after deployment. Before the antenna is deployed, as shown in FIG. 20 is fixed to a mounting bracket 22 provided on the satellite body 1, and rotational torque is obtained through an elastic string 18 by the force of a spring 17. After launch, when it is separated from the mounting bracket 22 by the explosion tube of the nut 21, the magnetically levitated object 10 rotates due to the rotational torque obtained by the force of the spring 17, and the antenna reflector 2 rotates around the fixed axis 8. It rotates and unfolds, and its pointing direction is directed toward the earth. When the attitude of the satellite changes due to disturbances such as solar radiation pressure or magnetic torque caused by the earth's magnetism, a sensor detects the radio waves emitted from the ground and uses a signal proportional to the amount of difference from the direction to control the electromagnetic force of the actuator 19. The position of the magnetically levitated body is finely adjusted and driven, and the pointing direction of the antenna reflector is controlled with high precision.

Note that a piezoelectric element may be used as the actuator 19 instead of the above-mentioned electromagnetic type. In that case, the piezoelectric element is brought into contact with the control piece 20, and the elastic deformation of the element 20 causes the actuator 19 to actuator 19 in the same manner as in the case of an electromagnetic actuator. Similarly, no permanent magnet is required for the 1° control piece 20, which can provide finely controlled driving.

As mentioned above, in the device of the present invention, the antenna reflector is inserted into the fixed shaft using a magnetic levitation body in a non-contact levitation state, so the frictional force caused by mechanical contact is eliminated when the antenna is deployed and when driving fine adjustment. It is possible to remove the lubrication part that becomes a problem in the high vacuum space environment.
It eliminates wear during long-term use, prevents characteristic deterioration, and makes the entire device highly reliable. Since the actuator directly drives the magnetically levitated body to which the antenna reflector is fixed, there is no problem of reduction gears that are required to use conventional motors, and the drive resolution is improved. It is possible to perform highly accurate pointing direction control.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of a three-axis stabilized satellite, Fig. 2 is a perspective view of an embodiment of the present invention, Fig. 6 is a sectional view of the magnetic bearing section, and Fig. 4 is a sectional view of the magnetic bearing section.
The figure shows an explanatory diagram of the state of the antenna reflector when it is deployed. DESCRIPTION OF SYMBOLS 1...Satellite main body, 2...Antenna reflector, 8...Fixed axis, 10...Magnetic levitation body, 19...Actuator,
20... Control piece half 3 (2) Figure 4

Claims (1)

[Claims] An antenna reflector is attached to a magnetically levitated body which is rotatably inserted into a fixed shaft fixed to the satellite body in a non-contact levitation state by magnetic force, and a control piece is provided on the outer periphery of the magnetically levitated body. An antenna driving device characterized in that an actuator for finely adjusting and driving the rotational position of the magnetically levitated body is disposed at a position facing the control piece.