JPS58101506A - Simple compensator for shaking for mobile body mounting device - Google Patents

Abstract

PURPOSE:To decrease the shaking of an antenna, by providing a brake for each rotating shaft of a universal joint mounting the antenna on a mobile body and activating the brake when the angle of the rotating shaft reaches a prescribed amount or over. CONSTITUTION:A brake is fitted to rotating shafts 7, 8 of a universal joint mounting an antenna 2. The antenna 2 and a radio equipment 3 form a pendulum. The link rod 4 is a universal joint formed with a rotary frame 6 and the shafts 7, 8 and fitted with a support 9 fixed to a mobile body. The shaft 7 is supported to the rotary frame 6 with a bearing 15 and a brake 16 fixed to a fitting plate 17 is coupled with the shaft 7. This brake is activated when the rotary angle of the shaft 7 reaches a prescribed amount or over. Thus, the shaking of the antenna due to the shaking of the mobile body (such as ship) can be reduced.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a sway compensating device, which is used when an antenna is mounted on a moving object such as a ship, and is used to reduce the shaking of an antenna due to the oscillation of the moving object. It can be used as a simple vibration compensation device for

(Background technology) For example, when the moving object is a ship, when communication is carried out between the ship and a flying object such as a communication satellite, when the ship is shaken by waves, the antenna attached to the ship is shaken by the ship's movement. . As a result, the main beam direction of the antenna deviates from the direction of the satellite, and the transmission and reception levels fluctuate, causing communication problems. As a countermeasure to this problem, a sway compensating device is required to stabilize the oscillation of the antenna.

As conventional antenna oscillation compensation methods, an active type using a servo mechanism and a passive type using gravity are used.

FIG. 1 shows an example of the configuration of a passive compensator. 1 is a radome, 2 is an antenna, 3 is a radio device, 4 is a connecting rod between the antenna and the radio device, and 5 is an integrated structure consisting of the antenna and the radio device (
6 is the rotation frame, 7 and 8 are the rotation axes, 9 is the support column, 10 is the mounting base, 11 is the mast of the ship, etc., 12 is the ship, 13 is the center of gravity of the ship, and 14 is the vertical axis. , θP, θ
The wings represent the pitching and rolling angles of the ship, respectively, and H is the distance between the center of gravity of the ship and the axis of rotation of the pendulum. In FIG. 1, the rotation axes 7 and 8 constitute a universal joint. Further, 7 and 8 are set parallel to the pitching axis and rolling axis of the ship, respectively. Since the pendulum swing due to pitching and rolling of a ship can theoretically be treated in the same way, the pitching direction will be explained below as an example.

The maximum amplitude in the pitching direction of the ship is expressed as θ-, and the maximum value of the amplitude θ of the pendulum at this time is θ□. Also, let l be the distance between the rotation axis of 7 and the center of gravity of the pendulum of 5.

FIG. 2 shows the calculated value of the relationship between l and θ. The conditions are as follows: amplitude θPm = 300, period T = 5 seconds, and distance H between the center of gravity of the ship and the axis of rotation of the pendulum = 1.7 m. With an appropriate value of l, the radius is the ship's rolling angle oP
It can be seen that it can be made smaller than m.

θ. In order to make l extremely small, l should be close to zero, but in this state, the rotational moment around the pendulum's rotational axis is small, so if there is even a small amount of friction on the rotational axis, the pendulum will swing due to frictional force. This causes the ship to sway with the same amplitude as the ship, making it difficult to design a rotating bearing. Therefore, l needs to be set to a somewhat large value so that the friction of the rotating shaft can be ignored. Practically speaking, as long as the length of the pendulum does not become too large, l is appropriate to be about 10u+, but the amplitude θ1 of the pendulum is only about 1f, and the beam width of the antenna is about 200, which is a relatively high gain. The drawback was that the suppression of vibration was not sufficient to support the antenna.

On the other hand, in the active type, a drive motor is attached to the rotating shafts 7 and 8 of the pendulum to compensate for the oscillation of the pendulum. In this case, in order to determine the drive angle by the motor, it is necessary to detect the oscillation angle of the ship or the tilt angle of the pendulum, and a oscillation detector using a vertical gyro or an accelerometer is required.This method provides high compensation. Although it has the advantage of high accuracy, it has the disadvantage of requiring the use of an expensive motion detector and making the whole device large and expensive.

(Problems to be solved by the invention) The present invention aims to solve these drawbacks, and provides a passive vibration compensator with a simple and inexpensive structure.
A braking mechanism is provided on the two mutually orthogonal rotation axes of the universal joint part to suppress the vibration of the antenna part, and the drawings will be described in detail below.

(Structure and operation of the invention) Figures 3 (a) and (bl) show an embodiment of the present invention. Figure 3 (al) shows the overall configuration, but the structure of the pendulum and support part is the same as in Figure 1. The same is true. Fig. 3(b) shows a detailed view of the rotating shaft portion.The feature of this embodiment is that the rotating shafts 7 and 8 of the universal joint have a braking mechanism.

15 is a bearing for rotating shaft 7, 16 is a brake for shaft 7,
17 is the mounting plate of the brake, 18 is the fixed part of the pendulum structure,
It is tightened and fixed with 19 screws. As the brake, for example, an electromagnetic brake can be considered.

Since the electromagnetic brake can change the braking force depending on the excitation voltage, the braking force relative to the rotation of the pendulum shaft can be controlled by controlling the excitation voltage of the electromagnetic brake.

The operation of this configuration will be explained below.

First, Fig. 4 shows the swing mode of the pendulum when full braking is not applied to the rotating shaft. (1) is the state where the ship is at the neutral point, (2) and (
3) is −+(a,
! It is in a transition state.

This state of oscillation of the pendulum corresponds to the value /=10 Tomomi in FIG. θP and θ are respectively transition state II! (4
1, θ8 is the swing angle of the ship and the boat in the transition state (
4) is the angle between the pendulum and the support column.

Further, θpm is the maximum value of θP, θ□ is the maximum value of θ, and 08m is the maximum value of θ8. If there is no braking, (1) → (4
) and (4)→(2), both θP and θ increase, and this is an oscillation mode in which θ8 increases.

On the other hand, an example of the oscillation mode when braking is applied to the rotating shaft, which is the point of the present invention, is shown in FIG. It is something that works or cuts.θ′.

θ2 is the swing angle of the pendulum during braking and the angle between the pendulum and the support column, respectively.

First, when moving from state m to state (4) toward (a)ic, strong braking is applied to the rotating shaft. Then, the pendulum is fixed to the rotating shaft, and θB becomes constant as θB-〇ni. Next, θP is θ
When Pr1l = θP + ΔθP and transitions to state (2), if the angle the pendulum makes with the vertical axis is θ', θ' becomes the state (
4) θ is smaller by ΔθP, and θ'=θ−Δ
It is given by θP, and the apparent swing angle of the pendulum can be reduced from θ□ by −θ+ΔθP. Next, when the state changes from state (2) to state (4), the braking is eliminated. In this state θ
, θP are exactly the same as in the non-braking mode, so if the braking is turned off at this point, the pendulum shifts directly to the non-braking mode. Expressing the time change of θ in a series of operations, the fifth
The result will be as shown in figure (b). (11 to (4) on the time axis correspond to states (11 to (4)) in FIG. 5 (al), respectively.

The same is true when the ship sways to the right; by repeating these operations, the oscillation of the pendulum is suppressed compared to when the brakes are not applied. There is an advantage that it can be done.

When the brake is operated all the time,
The swinging mode of the pendulum is as shown in the example shown in Figure 6 (al). This is the swinging mode of the pendulum when the ship is swinging from left to right; swings in the opposite direction.The time change of θ at this time is shown in Figure 6 (
Shown in bl. The oscillation specifications are the same as the conditions shown in FIG.

Braking force is 2.8kg-fi as torque around the rotation axis
is the value of The maximum value of θ is approximately IFf', which is 1 when not braking.
It becomes larger than 1°. As the braking torque is made smaller and approaches zero, θ also becomes smaller, but it only approaches asymptotically to θ when braking is not applied, and there is no effect of reducing θ.

Next, a description will be given of the configuration of the vibration sensor that provides the judgment criterion for starting and stopping the operation of the brake machine in state (4) of FIG. 5(a). FIG. 7 shows an example of the configuration of the vibration sensor.

The holder is the housing of the vibration sensor, 21.22 is the pendulum weight,
n, 24 is a screw for adjusting the position of the weight, 5 is the center of gravity of the pendulum, % is the fulcrum of the pendulum, n is the rotation angle detector, and A is the support of the pendulum. The natural frequency of the pendulum is given by. Here, m is the total mass of the pendulum weights of 21 and n, g is the acceleration of gravity, lo is the distance between the center of gravity of the pendulum and the fulcrum, and ■ is the moment of inertia around the fulcrum of the pendulum. If the moment of inertia around the center of gravity of the pendulum is IG, then ■, == ■a, + m1lo.

Furthermore, if the upper and lower weights of the pendulum are composed of disks of the same shape, and the interval between the weights is h, then l can be expressed as small. Therefore, if you adjust the position of the pendulum weight of the vibration sensor with screws 23 and 24 and select the appropriate lo, it will have a natural frequency equal to that of the integrated structure consisting of the antenna and radio, and will be far greater than the integrated structure. A small pendulum can be constructed. At this time, the oscillation of this pendulum is the same as the oscillation mode during non-braking shown in Fig. 4, and the operating point of the brake (
4) can be detected by a rotation angle detector n installed at the fulcrum of the pendulum. Rotation angle detectors are installed on each of the two rotating shafts of the pendulum's universal joint that rotate independently of each other, and detect the angle that the pendulum makes with the support (08 in Figure 4) with respect to the movement of the ship. It is something to do.

As explained above, the present oscillation sensor only needs to obtain the angle formed by the pendulum and the support, and there is no need to provide a vertical axis like in a conventional vertical gyro, which has the advantage of simplifying the configuration and making it inexpensive. Another advantage is that unlike conventional pendulum-type inclinometers, there is no need to install the inclinometer near the center of gravity of the ship to account for the effects of acceleration applied to the pendulum weight, making it easier to handle. be.

In addition, although the above explanation has been made using antenna oscillation compensation as an example, the present invention can be applied to oscillation compensation of general devices other than antennas, such as buoys floating on the water surface, marine repeaters, and offshore oil field communications. In addition to this, it is also possible to apply it to a gyro.

(Effects of the Invention) As explained above, the motion compensating device of the present invention is composed of a pendulum consisting of an antenna and a radio device, and has two rotating shafts of a universal joint that rotate freely in response to the motion of the ship. Since this method suppresses the swing of the antenna by providing a brake for each brake and appropriately adjusting its operating timing, it maintains the features of the passive type, which allow it to be made compact and inexpensive, while maintaining the antenna's This has the advantage that the swing angle can be made sufficiently small. Therefore, this device is effective when installing a satellite communication antenna in a small ship weighing several tens of tons, which requires a small and economical device.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a passive sway compensator, Figure 2 is a diagram showing the relationship between the distance between the center of gravity of the pendulum and the fulcrum and the amplitude of the pendulum.
3(a) and (b) are block diagrams of an embodiment of the device of the present invention, FIG. 4 is a diagram showing an example of the pendulum oscillation mode when not braking, and FIG. 5(a), (bl and Figure 6(a),
(b) is a diagram showing the oscillation mode of the pendulum during braking, No. 7
The figure is a configuration diagram of an agitation detection sensor. 1...Radome, 2...Antenna, 3...Radio device, 4...Connection rod between antenna and radio device, 5...
... Center of gravity of the integrated structure (pendulum) consisting of an antenna and a radio, 6 ... Rotation frame, 7, 8 ... Rotation axis,
9... Support column, 10... Mounting base, 11... Ship mast, etc., 12...
・Ship, 13... Center of gravity of the ship, 14...
... Vertical shaft, 15 ... Bearing, 16
...Brake, 17...Brake mounting plate,
18...Fixed part of the pendulum, 19...
Screw, addition...Movement sensor housing, 2
1.22... Weight, 23.24... Adjustment screw, 5... Center of gravity of the pendulum of the vibration sensor, 26.
...rotation axis, moss...rotation angle detector, ah...prop hair/Figure/A No. 2 Fig. 1. Act 321 ta+ <l)) Izumi i
Illustration 5 Diagram ((7) Traroguchi (0) Q) t4ノ Ill (3) Ootsu 121 (
bJ

Claims (2)

[Claims] (1) In a motion compensation device for a mounted device that is mounted together with a weight via a universal joint that has two orthogonal rotation axes that can rotate independently of each other, each of the universal joints A brake is provided on the rotating shaft, and a rotation angle detector is provided to detect the rotation angle of each rotating shaft, and when the rotation angle of the rotating shaft of the universal joint portion is equal to or greater than a predetermined angle with respect to the reference state. A simple vibration compensation device for a mobile body-mounted device, characterized in that the brake is configured such that the brake is actuated. (2) The mobile body mounting according to claim 1, wherein the rotation angle detector has a natural frequency substantially equal to the natural frequency of the mounted device and has a pendulum that is much smaller than the weight. Simple vibration compensation device for equipment.