JPS5979604A - Driving device of antenna - Google Patents

Abstract

PURPOSE:To control highly accurately the directivity of an antenna for an artificial satellite and to improve the reliability of a driving device by driving the antenna by using an elastic body and a piezoelectric element. CONSTITUTION:A directivity sensor circuit 1 receives a sensor signal of an antenna directivity by radio waves from a ground station and sends the received signal to a control circuit 2. The control circuit 2 operates the signal so that the error of the antenna directivity is minimized and then a driving circuit 3 converts the information from the circuit 2 into a driving voltage signal. Driving parts 4-6 consisting of piezoelectric elements expand or contract straightly in accordance with the driving voltage signal. The driving replacement is transmitted to the antenna 9 and directs the antenna 9 in an optional direction around the axis vertical to the body 12 of the satellite through the center of an antenna fitting board 10. Said constitution can attain minute driving of the antenna 9 and controls the directivity of the antenna 9 extremely accurately. The driving parts 4-6 have no frictional part and enabled to have redandant structure, so that high reliability and high life of the driving device can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly accurate and highly reliable artificial satellite antenna driving device.

Satellite communications are currently in widespread commercial use in countries around the world due to their wide area coverage and ease of line setup. In order to make the system more economical, we plan to increase the transmission capacity.
In order to popularize simple and compact earth stations that can use satellite communications, a multi-beam system is being considered in which multiple large antennas are mounted and multiple irradiation beams are provided. Furthermore, as the scale increases, a longer life is required. In this case, since the pointing accuracy of each antenna must be ensured for a long period of time, it is necessary to minutely drive each satellite-mounted antenna individually with high precision and with a highly reliable structure.

Conventional devices of this type generally use a step motor as a drive source, and use components such as gears or ball bearings as a drive torque transmission mechanism. However, in a drive device using such parts, there is a limit to the improvement in precision due to gear deformation, backlash, etc., and this poses a problem for high-precision drives that will be required in the future. Furthermore, it is expected that it will be extremely difficult to maintain the lubricity of the frictional parts of the drive in devices that are subject to frequent, long-term micro-movement under the high vacuum conditions of space, making it difficult to ensure long-term reliability. be.

Therefore, it can be said that the conventional drive system has fundamental problems as a high-precision, high-reliability antenna drive device for large-scale satellites expected in the future.

The present invention is characterized in that an artificial satellite antenna is driven using an elastic body and a piezoelectric element, and its purpose is to control the pointing direction of the antenna with high precision and to improve the reliability of the drive device.

FIG. 1 shows an embodiment of the present invention, in which 1 is a pointing direction sensor circuit, 2 is a control circuit, 3 is a drive circuit, 4.5.6 is a drive unit using a piezoelectric element, 8 is an elastic body, 9 is the antenna, 1
0 is an antenna mounting base, 11 is an antenna base, 12 is a satellite main body, and 14 is a power feeding section.

FIG. 2 shows details of the structure of the drive section 4.5.6. 15 in Figure (a) is a piezoelectric element with a laminated structure as shown in Figure (b). Two sets of this laminated structure are used, and normally only one of them is used, and in case of a failure etc., the other is used. It has a redundant configuration. The reason for the laminated structure is to increase displacement and driving force.

The piezoelectric element 15 is made of a heat insulating material 7 having radiation resistance and cosmic ray resistance so that its function can be fully demonstrated in outer space.
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In this way, the drive unit 4.5.6 is attached to the antenna mount 10 by the attachment part 13-1 and to the antenna base 11 by the attachment part 13-2. Mounting part 1
3-1 and 13-2 are made of an elastic material that can cope with the inclination caused by the inclination of the antenna 9.

The operating principle is that when a DC voltage is applied to a piezoelectric element,
This utilizes the piezoelectric effect that causes deformation in proportion to the applied voltage, and the drive section 4.5.6 expands and contracts in response to the drive voltage signal from the drive circuit 3. The antenna 9 is attached to an antenna mounting base 10, and the antenna mounting base 1
0 is installed on the antenna base 11 by the drive unit 4.5.6 and the elastic body 8, and the core base 11 is further attached to the satellite main body 1.
It has been identified as 2.

The pointing direction sensor circuit 1 generally receives a sensor signal indicating the antenna pointing direction using radio waves sent from a ground station, and sends the signal to the control circuit 2. In control circuit 2,
After performing arithmetic processing so that the antenna pointing direction error is minimized, the information is converted into a drive voltage signal (
The plurality of drive units 4.5.6, which are converted into direct current voltage (DC voltage), linearly expand and contract in response to this drive voltage signal. The driving displacement is then transmitted to the antenna 9 via the elastic body 8 and the mounting portion 13-1.13-2 provided at the end of the driving portion 4.5.6.

FIG. 3 is a diagram showing an example of the positional relationship between the drive section 4.5.6 and the elastic body 8. As in the embodiment, the elastic body 8 is arranged at the center of the antenna mounting base 10, and three drive parts 4, 5.
6 are placed around it.

Generally, a plane is determined by three different points that are not on a straight line at the same time, so the drive range is determined by the three drive units 4.5.6 expanding and contracting linearly in response to drive voltage signals. The plane containing the antenna mount 10 can be set in any direction within the antenna. In other words, the antenna mounting base 1
The antenna pointing direction can be set in any direction around the axis υ perpendicular to the satellite body 12, with the center of 0 being the center of the satellite.On the other hand, the deformation due to the piezoelectric effect follows the applied voltage extremely accurately, so it is possible to change the applied voltage. By doing so, minute displacements can be easily obtained and the antenna can be controlled with high accuracy.

In practice, a digitally varying applied voltage is used. Furthermore, the driving range can be freely set depending on the mounting position of the driving section 4,5,6.

Furthermore, in an antenna drive device having such a structure, since the drive section has no frictional parts, the difficult problem of maintaining the lubricity of the frictional parts does not occur, and by making the drive section have a two-stage structure, Even if one of them breaks down, it will not affect operation. In addition, since piezoelectric deformation is used, the driving force is large and the response is good.As the piezoelectric element, one of ordinary PZT with a large piezoelectric constant is used.
Cover the surrounding area to prevent it from being affected by radiation or cosmic rays.

As explained above, since a piezoelectric element is used in the drive section, minute drive is possible by controlling the drive voltage, and the directivity direction of the antenna can be controlled with extremely high precision. Furthermore, since the drive section has no frictional parts and a redundant structure is possible for the drive section, the reliability of the device itself is improved, and it is expected that a highly reliable and long-life antenna drive device for satellite use will be realized.

Furthermore, since the driving force and responsiveness are superior compared to step motors, etc., it is possible to expand the range of the antenna driving amount and driving speed, and the antenna is highly versatile as a driving device.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment according to the present invention, Fig. 2(a)
2(b) is an enlarged view of the driving section, and FIG. 2(b) is a diagram showing the laminated structure of the piezoelectric element. FIG. 3 is a diagram showing an example of the positional relationship between the drive section and the elastic body. 1... Directional direction sensor circuit, 2...
...Control circuit, 3... Drive circuit,
4.5.6... Drive section, 7...
...Insulating material coating, 8...Elastic body, 9.
......Antenna, 10...Antenna mounting base, 11...Antenna base, 12...Satellite body , 13-1 , 13
-2...Mounting part, 14...
・Power supply section, 15...Piezoelectric element agent Patent attorney Takashi Honma Fig. 7 19 Fig. 2

Claims (1)

[Claims] An antenna driving device comprising: an antenna driving section that mechanically changes the pointing direction of an antenna beam by changing the dimensions of the piezoelectric element in a specific direction by changing the voltage applied to the piezoelectric element.