JPS59161101A - Stable antenna unit with accelerating moving mass - 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 provides a method for antennas to be supported on equipment that is subject to pitching and rolling, such as ships at sea, balloons moored to offshore drilling platforms, land vehicles, airplanes, etc. The present invention relates to a stable antenna device that can be stabilized when Although described herein with reference to a ship, those skilled in the art will appreciate that the principles and features of the invention are equally applicable to other equipment subject to pitching and rolling motion, periodic vibrations and motion. It is.

There are many applications where an antenna must be supported on a ship at sea or another structure that is subject to pitching and rolling. In satellite-supporting parabolic antennas and other high-gain antennas, it is desirable to keep the antenna pointing generally constant.

With the exception of rare calm seas, antennas mounted directly on the deck of a ship may suffer from unacceptable pointing errors and loss of satellite acquisition under typical environmental conditions. High performance,
For narrow beams and military equipment, the degree of indication error is acceptable. It is therefore desirable to support the antenna on a stable platform.

In the past, co-axis and tri-axis tracking antenna devices have not been fully satisfactory. Co-axis pedestals are inherently limited to less than the full hemispherical coverage area due to the 'keyhole' effect when the target is located near the extension of the primary axis where the acceleration and velocity required for corrective motion are intolerable. Although triaxial pedestal antenna arrangements provide full hemispherical coverage, they are unacceptably expensive and complex for most economical applications.

For example, a very sophisticated control system with a closed-loop servo control system for each axis may have a digital heater that performs complex coordinate transformations.
Used in devices such as accelerometers and other equipment along with compound rate gyros. Such complex and expensive equipment is unsuitable for many applications.

Although complex l-axis servo systems exist, they must be expensive in order to be sufficiently reliable. The invention consists in obtaining reliable stability without a servo control at a very low cost.

The average time between outages is approximately inversely proportional to the complexity of the device. The permissible average time between outages is particularly important for the use of antenna equipment. For example, in maritime applications, stopping at sea is expensive and very inconvenient.

In many marine applications, the antenna is mounted on a very high mast or tower above the deck of the ship. This is normal, but in relation to the color of the ship, it is desirable to set it to 5 so that parts of the ship's structure do not impede visibility. The antenna is often mounted at the top or stern of the ship's neck, at a large angle from the center of the ship. As a result, the antenna is exposed to linear acceleration forces as the ship pitches and rolls, usually about a point near the center of the ship. Such linear acceleration forces will tend to tilt the platform, exerting a destabilizing effect on the antenna platform, and many of the 5° stable platforms that have been proposed are useless for compensating for linear acceleration forces. A large number of known patents fail to acknowledge the problem of linear acceleration. In fact, the applications disclosed in the prior patent specification do not include a satellite antenna stabilizer mounted on a ship. The environment for antenna stabilizers on ships is quite different from that disclosed in prior patent specifications. On a ship, the antenna is far from the center of motion and usually mounted high on the mast. This environment is characterized by linear acceleration forces.

In some ships, the linear acceleration forces are large enough to destabilize a gyroscopically stabilized platform not constructed in accordance with the present invention and to remain unstable for a significant period of time.

There is a need for a reliable and stable antenna system with an economically acceptable cost system. Although this is a relatively low cost, it is necessary to develop a reliable antenna system with the new °L" band frequencies applied to maritime satellite communications.

From the above, the conventional antenna device is fully satisfied (/!;
) I can't do it. The present invention overcomes all of the disadvantages mentioned above.The present invention has the feature of an accelerating moving mass that compensates and cancels the forces due to linear acceleration. The present invention features a stable platform with independent azimuthal drive of the antenna. The antenna's azimuth drive is a compass that follows the stable platform to maintain a nearly constant orientation when the ship is flipped downwards and when the ship is flipped rapidly for purposes such as rewinding cables. That's fine.

The above features include combination with a gimballed antenna structure on a substantially vertically oriented azimuth axis.

The present invention has a center of gravity located slightly below the gimbal device structure. The center of gravity must not be located too far below the gimbal device.

The reason for this is that a large couple is generated and the antenna pedestal is susceptible to instability due to horizontal acceleration.

The present invention is designed in the ≠ axial form, the two axes of which are provided with control interfaces and the other co-axis is passively stabilized to produce the required complex control and (/6) normal λ-axis, 3-axis and μ-axis devices also have much better reliability.

The present invention features a pendulum-shaped accelerating moving mass. An advantageous embodiment of the invention is characterized by an upper gimbal arrangement having a compound transducer resonant frequency that is more than io times smaller than the resonant frequency of the transducer accelerating moving mass. Adding a gyroscope to the upper gimbal device is an expensive low-friction device.
Without the use of load bearings, the resonant frequency of the device is significantly lowered, reducing the difficulty of balancing the upper gimbal device.

The present invention will be described in detail below based on a plurality of embodiments shown in the drawings.

More particularly, advantageous embodiments of the invention use a combination of features to yield good overall performance of the stable antenna system. The device also preferably has a center of gravity slightly below the gimbal axis in order to obtain a length reference with respect to gravity, and a stabilizing platform is preferably mounted on the mutually orthogonal rocking axes supported by the platform. It has two gyroscopes. This gyroscope is used to reduce errors due to transient torques and to lower the complex transducer resonant frequency of the upper gimbal device. Gyroscopes act like mechanical filters to store and release energy to quieten the rolling and pitching typically experienced by ships at sea. Additionally, the present invention includes an accelerating moving mass to compensate for linear acceleration forces.

The antenna 3/ must first acquire a desired target, such as a communications satellite, in earth orbit via some control scheme. This acquisition control is controlled remotely.

Acquisition control generally requires at least altitude and heading control. It is thought that similar results can be obtained with an equatorial mount system having azimuth-related arrival control and azimuth angle control.

The illustrated l@i anti≠ device 50 has one control axis formed with respect to altitude and crowd, and these control axes are formed on a two-axis gimbal s3.

This gimbal 33kt can be understood in detail in FIG. From FIG. 7, the axis t/ and the azimuth axis n are located above the gimbal S3. Gimbal S3
is the first gimbal axis 33 and this seventh gimbal axis S
3, and a second gimbal axis preferably perpendicular to the second gimbal axis. In other words, gimbal j3 has orthogonal gimbal axes 1r3, t'A.

Once the satellite target has been acquired, the pointing attitude of the antenna S must be updated for changes in bow direction and ship position. Changes in the bow are preferably automatically compensated for in the azimuth axis by having the azimuth drive 3 follow changes in the direction of the bow and the position of the ship. Also, in the case of ships such as cargo ships where the direction of the ship's bow remains approximately constant over long periods of time, changes in the position of the ship's bow and the ship are performed manually. In some cases, an orbital error of less than ioo miles of cruising speed may occur.

It is important to provide an altitude control axis U and an azimuth control axis t4 above the gimbal axis, where the pitch and roll axes of the gimbal device of the stability pedestal are the control axis that the azimuth control device follows. It runs parallel to the pitching and rolling axes of the Kusu.

If the azimuth control device, generally designated 7.20, is placed below the gimbal axis ra, trti-, an indication error will occur.

If the antenna 3/ is installed on a ship SS, the problems caused by the six main movements of the ship have to be taken into account: pitching, rolling, yaw, forward motion, heave and heave. Yaw motion is generally steered by having the heading control follow the ship's compass. Movement of the ship SS requires the antenna controller SO to quickly and accurately compensate automatically for angular changes in order to prevent excessive pointing errors and to prevent signal degradation or loss. .

In FIG. 7, the antenna device 3o is preferably provided at a position as high as possible on the deck of the ship 3S.

This means that regardless of the pointing angle of the antenna 3 and the orientation of the bow of the ship SS, the antenna S is caused by obstructions such as the ship's mast, chimney, command tower and other physical obstacles present. This is desirable because it does not suffer from signal degradation or loss due to such interference. In a typical installation as shown in FIG.
is placed at the stern, away from the center sr. In a typical installation as shown in Figure 7, the antenna S is mounted on a stable platform octopus;
- has a gimbal joint S3 supported on the tower 3g. Preferably, a V-dome 6 is provided to reduce the wind force on the antenna S.

The antenna, 1/, mounted on the stable platform octopus in FIG. 2, is mounted on the support S7 with this platform phantom as schematically illustrated.

In Figure 2, the ship pitches around its center 5g. Antenna support S7 is located at the pitching center SI of the ship SS.
It is placed at a distance from The antenna platform j:I is placed at a distance H from the plane of the pitch center 5g.

The antenna platform A5 is swingably mounted on the support S7 at a point p, which in the illustrated embodiment is a gimbal joint. The center of gravity of the antenna device is indicated by points C and G, and this point (G is located below the gimbal joint p. The center of gravity C0G is initially aligned with the vertical axis 101
It makes noise when placed on top of it.

The antenna arrangement SO with antenna j/and platform j2 is exposed to linear acceleration forces when the ship S5 pitches about its center SIr. For example, ship SS
When the support S7 pitches forward about the center 3g in the direction indicated by the arrow S9, the support S7 rotates counterclockwise in FIG. This generates a force acting on the gimbal point p, which can be resolved into a vertical force component and a horizontal force component. The horizontal force component is designated by the symbol A in FIG. It is considered that the horizontal component A of the force acting on the gimbal point p causes linear acceleration of the antenna device SO. Linear acceleration is also sometimes called horizontal acceleration.

It is considered that the force A acts on the antenna device 3o through the point p. The centers of gravity C and G are located below point p and separated by a distance. Therefore, a force such as A due to the linear acceleration of the antenna device 50 tends to tilt the platform 5.2 in the direction indicated by the curved arrows i, o. In other words, the linear acceleration force produces a rotational moment about the centers of gravity C, G, which in the illustrated embodiment is directed in the direction indicated by the curved arrow AO.

The optimal vertical position of the centers of gravity C, G is determined between the expected friction hysteresis and worst-case linear acceleration for a given application. The worst linear acceleration is accommodated by different shapes and sizes of ships and by different positions at sea. These factors may also be more or less applicable to installations in other forms of vehicles such as balloons, airplanes, offshore drilling platforms, etc., depending on the particular application situation.

With minimal error due to horizontal linear acceleration, the centers of gravity C, G are ideally placed coincident with the gimbal point p. In the embodiment shown in FIG. 2, when the centers of gravity C and G are aligned with point p, the force A due to linear acceleration acts directly on the center of gravity C1G, and no rotational moment in the direction of the arrow to is generated.

That is, the distance between the centers of gravity C and G and the gimbal point p is zero.

In other words, the rotational moment at the center of gravity C and G is the distance i
It is the same as the product of n and the forces acting on the centers of gravity C and G. If the distance is zero, the product of this force and the distance is also zero, and the rotational moment is also zero.

However, in order to minimize errors due to friction and hysteresis, as well as errors in providing the length term reference and bias oscillator weight to the antenna device 3o, the center of gravity should be located as far below the gimbal point p as possible. is desirable. In other words, to minimize indication errors due to friction and hysteresis, the distances shown in FIG. 2 are made as long as possible.

Preferably, the optimal vertical position of the center of gravity is negotiated between the minimum error of indication due to frictional hysteresis and the minimum error of indication due to linear acceleration, and since these factors vary with different application conditions at different locations. Center of gravity C, G
A position-adjustable counterweight is provided to adjust the distance between and the gimbal point p. The distance can also be considered as the distance between the centers of gravity C and G and the plane where the gimbal axis intersects.

The adjustable counterweight is in the form of an extension rod extending downwardly and having a thread at the bottom, which is attached to the bottom of the platform 32 and allows the counterweight to be adjusted by screwing along the threaded rod of the counterweight. You can adjust the weight up or down. In this way, the center of gravity can be adjusted up or down to facilitate target tracking for specialized equipment.

In typical equipment on ships running at sea, the center of gravity C,
G is preferably placed as close as possible to the gimbal point p and offset by a distance 119D just enough to overcome the bearing friction or friction at gimbal S3 plus some safety factor. In the preferred embodiment, the centers of gravity C, G are offset a distance of approximately 0.7 inches below the gimbal S3. This offset distance is preferably o, io, r
It should be in the range of 0.07 to 3.0 inches, depending on the size and shape of the antenna pedestal, the location, environment, and type of movement to which the antenna device is exposed.

If the expected conditions of the facility environment are approximately the same, the counterweight does not need to be aligned with respect to a special antenna pedestal once the optimal location of the center of gravity is determined.

In FIG. 3, the effect of linear acceleration is offset by the provision of an accelerating moving mass 6j. FIG. 3 schematically shows how the accelerated moving mass Aj is utilized to move the center of gravity C0G and how to compensate for the unstable forces due to linear acceleration.

Accelerating moving mass 6j is in an initial position indicated at 43 in FIG. In the example shown in FIG. 3, an upper moving mass 6S and a lower moving mass 6j are provided. In this illustrated example, the accelerating moving mass 63 is connected to the platform octopus by a resilient member 6t. This elastic member 6t may be a spring. The platform phantom and antenna arrangement has a center of gravity tlI located below the gimbal joint j3.

In the force A due to linear acceleration, rotational torque in the direction of the curved arrow to is generated around the center of gravity A+.

However, force A due to linear acceleration causes the accelerated moving mass 63 to move to the position indicated at 46' in FIG. The inertia of the accelerated moving mass tS causes the accelerated moving mass 43 to move in the direction shown by arrow 103. Position 63 of accelerated moving mass 6j
To move to the position indicated by 1, change the actual center of gravity to 441
' to the new position indicated. In other words, the accelerating moving mass 6j is positioned in response to the force due to linear acceleration, dynamically following it so as to offset the destabilizing effect of this force, as will be described later.

When the accelerating moving mass 6j is placed at the position 43' and the center of gravity moves to the position 64/, the center of gravity 6! I' moves horizontally from gimbal S3 by a distance X. Center of gravity Al
The gravitational force acting on l' produces a rotational torque in the direction indicated by curved arrow 102 in FIG. 3, i.e. in this clockwise direction. The rotational moment due to gravity is the product of gravity and distance @X. Note that the rotational moment generated by the displacement of the center of gravity All' is in the direction 102 opposite to the direction AO of the rotational moment generated by the force A due to linear acceleration. Therefore, the displacement of the accelerating moving mass 6j and the position tracking of the center of gravity 61I attempt to offset the unstable effect of the force due to linear acceleration.

The compensating rotation moment in direction 10 can be adjusted by changing the distance X of the center of gravity 69' under predetermined conditions. In the embodiment shown in FIG. 3, this can be done by changing the size of the mass 6j and the distance between the mass 65 and the gimbal 53 (ie, the length of the elastic member). The compensating rotational moment in direction 102 can also be made the same as the moment in direction Aθ due to linear acceleration by reducing the linear acceleration moment. This can be done, for example, by reducing the distance between the center of gravity 611 and gimbal j3. It is desirable that the displaced center of gravity AII' is not moved to a lower position than the initial center of gravity A4.

This occurs if the accelerating moving mass 6j is provided only on the platform phantom. It is therefore desirable in this illustrated embodiment to provide the accelerating moving mass 4.5 below the plane of the platform phantom, so that the distance is such that the center of gravity is at position 4II in accordance with the movement ts' of the accelerating moving mass.
It will not become longer if you move to '.

The figure below shows the preferred form of the accelerating moving mass. In this example, the accelerated moving mass -〇〇 takes the form of a pendulum. The accelerated displacement mass KO00 is preferably of spherical design. The shaft 20.2 connects the accelerating moving mass 200 to a hypot joint, such as a gimbal 203, preferably formed as a U-joint.

The gimbalco 03 is a ball and socket joint or a link that allows free movement of the accelerating moving mass 200 in the horizontal direction. The accelerating moving mass θO can also be suspended by a cable.

In the illustrated embodiment, the gimbal 203 is attached to the stabilizing pedestal 20.
sabot attached to j) is connected to 2011.

In the figure, 200 is the 200 pedestal 2.
01 vertical axis, stable pedestal near 20 Otsu, 20! is attached to. Stable pedestal, 20j is gimbal device 2
Supported by 07. Horizontal or linear acceleration forces tend to move the accelerated moving mass, 200, from its initial position shown in FIG. The embodiment shown in FIG. 2 is also referred to as a composite swing-cross antenna stabilizer that uses an accelerating moving mass 200 suspended in swing-cross fashion. This embodiment has particular advantages during start-up and transient response. This embodiment also places the accelerating moving mass 200 in a stable position.

It is desirable to have an advantageous transient response for a stable antenna pedestal. Most of a ship's thrusts (other than the ship's forward motion) are generally sinusoidal.

However, the energy from the ship's motion transferred to the antenna stabilizer sometimes has non-sinusoidal transient components, which can be characterized as, for example, a step, vup, sawtooth, or pulse function. Such transients result from rough seas, irregular waves, and other environmental conditions.

If the energy content of the transient is relatively small, the transient produces a torque to which an accelerating moving mass with a large second moment of inertia cannot respond completely effectively.

The stabilizer described above has features intended to improve transient response and overall device performance. gyroscope,
The addition of 20 smooths out the transients, thereby accelerating the moving mass, 200 stabilizes the pedestal, and 20! It is possible to effectively respond to the torque exerted by IfC. A gyroscope, which stores energy generated by transient motion,
It releases energy υ over a period of time that can be effectively handled by the stabilizer.

The gyroscope, 20, has an important auxiliary function. The stable platform, 20j, wobbles slightly to form a length vertical reference.

The vibration period of the upper gimbal structure can be derived or determined empirically. It is desirable that the entire upper gimbal device has a complex pendulum resonance frequency that is at least 10 times smaller than the resonance frequency of the accelerated moving mass -〇〇. Such a small resonant frequency eliminates the need for heavily loaded bearings with very low friction and is thus economically viable. This low friction bearing is needed because of the very small center of gravity offset distance required. The addition of 20 gyroscopes significantly lowers the resonant frequency of the upper gimbal device,
Eliminates the need for low friction bearings. The slight vibration of the gyroscope motor on the other hand causes the gimbal, 20
Attempts are made to overcome the initial frictional force existing in the 7 bearings.

The upper gimbal structure also requires careful static balancing during installation, but the gyroscope 20
The addition of the upper gimbal device makes it easier to balance the upper gimbal device during installation, reducing the need for precautions to maintain balance.

The accelerating body i-, 200 is suspended a distance "O" (not to be confused with zero) from the gimbal axis -O7. The magnitude of this distance "O" is correlated with the weight "'" of the accelerated moving mass λ00. It is desirable to limit the distance "O" to a more convenient length and to improve the response time of the accelerating moving mass 200. It is desirable to have a response frequency as high as possible for fast response to the accelerating moving mass, but this response frequency should not be as high as 3H due to vibration problems. Due to the interaction between the weight “9” of the accelerating moving mass and this pendulum distance “O”, the weight “W8” of the accelerating moving mass t roo
By increasing ', we can reduce the distance "o" by keeping other elements the same.

The weight of the spherical accelerating moving mass 00 as shown in Figure 2 is the product of the total weight of the upper gimbal device x the offset distance h of the center of gravity of this device. It must be equal to the value divided by the pendulum distance “O”. That is, the weight "vortex" of this accelerated moving mass is given by the following equation.

a X h W&″″ O From this equation, it can be seen that if the weight of the accelerated moving mass is made too small, the pendulum length of the accelerated moving mass will be too long.

The antenna device on gimbal-O7 has a center of gravity Ot, which is offset by a small distance below the gimbal device 207. This slight offset is preferably just large enough to overcome the gimbal, the friction at 207 K plus the safety factor. The safety factor takes into account bearing fatigue, lubricant degradation, weather, temperature changes, and other conditions that affect bearing friction. Center of gravity C, G
The offset distance is that platform 20! should not be made too long as it will respond excessively to horizontal or linear acceleration.

The offset distance of the centers of gravity C, G forms the length term for the gravitational force that tends to maintain the antenna arrangement above Jinparco 07 in the vertical direction in the absence of any other movement. If the initial center of gravity C, G offset distance "'h" is about 7.77 inches, not including the accelerating mass -li & 200, it will produce satisfactory results for the /3j bond device.

If an accelerating moving mass 200 is added as shown, the center of gravity will be raised. Accelerated moving mass shown, 200
is added, preferably the center of gravity offset distance increases to the static offset distance of the static center of gravity C, G, which is approximately o,p inches. The total center of gravity offset distance of the upper gimbal device and the accelerating moving mass is preferably Q/~4r
In the range of inches, but can also range from o, oi to 3.0 inches.

A displacement of the accelerating moving mass -00 results in the position of the center of gravity of the entire stabilizing device, i.e. the entire upper gimbal device and the accelerating moving mass t
soo moves. The entire stabilizer thus has a dynamic center of gravity that moves and changes position during operation. The stabilizer is designed such that the center of gravity of the entire stabilizer responds dynamically against the torque resulting from linear acceleration forces.

Embodiments of the present invention are constructed with one step in mind:

1) Select gimbal bearings based on life and shock loads rather than considering small friction.

2) Gimbal axis center and upper gimbal? The C, G offset distance from the center of gravity of the gimbal 207 is determined to be the smallest to produce sufficient pendulum return force to overcome bearing friction in the gimbal 207.

3) Size the accelerating moving mass 200 so that it offsets the torque acting on the upper gimbal device due to horizontal or linear acceleration.

4) Size the gyroscope 209 sufficiently to overcome the expected transient forces.

The first three items listed have already been mentioned above.

One of the advantages of the present invention is that expensive low friction gimbal bearings are not required. Determination of the minimum offset distance of the center of gravity can be done empirically. As mentioned above, a safety factor, typically a safety factor of 51, is preferably added to the value of the C0G offset distance.

The weight 'W1 of the accelerating moving mass 1k200 is the tilted pedestal 2
It is decided by referring to the worst situation for 05. Considering that the pedestal 205 is tilted 90 degrees from its initial horizontal position, the torque due to the weight of the upper gimbal device (without considering the weight of the accelerating moving mass) is It is equal to the product of the total weight 'Ws' and the offset distance 1hI of the center of gravity of the upper gimbal device (without considering the weight of the accelerating moving mass). The amount of accelerated displacement mass 200ON is preferably designed such that it produces approximately the same torque as the torque calculated by 'WsXh'. The torque of the accelerating moving mass is the accelerating moving mass 20
It is equal to the product of the M electric current Wa' of 0 and the effective distance '0# between the gimbal 207 and the point where the weight of the accelerating moving mass acts. Distance 10', also referred to as the accelerated moving mass offset distance in the illustrated embodiment, is the distance between the gimbal 207 and the accelerated moving mass gimbal joint 203. Pedestal 2
If we consider that 5 is tilted by 9[)0, the accelerated moving mass 2
The torque produced by 000 weight is 'WaXσ.

In fact, as mentioned above, the torque generated by the accelerating moving mass can be less than 'W@Xh' and the invention will still produce satisfactory results.

If the torque produced by the accelerating moving mass is slightly smaller, the stability pedestal 205 will always tend to be in an upper position since the torque due to the center of gravity return force is slightly greater than the torque produced by the accelerating moving mass 200.

The torque generated by the accelerating moving mass t200 is 'WaXO
' is. Weight 'Wa' and offset distance M10
Various combinations of ' result in equivalent accelerated moving mass torques. In a given design, the offset distance 10' of the accelerating moving mass is chosen to be a convenient length. In that case, the weight 'Wa' of the accelerated moving mass 200 is determined by the following formula.

Wa ×h Wa - For the antenna pedestal 205 of 135 phon P, the offset distance 10' of the accelerating moving mass is actually convenient and effective in order to provide an accelerating moving mass of weight 'Wa' of 16 bonds. It can be decided.

Another way to determine the optimal dimensions of the accelerating mass fk 200 is to calculate the total moment about the gimbal 207. The total moment about the gimbal 207 (without considering the accelerating moving mass 200) is equal to the product of the second moment of inertia 'Ims' of the entire upper gimbal device and the angular acceleration 'a, II of this device.

The following analysis can be better understood with reference to FIG.

The horizontal acceleration error torque can be considered to be the same as the following equation.

h Ma axco8S where 'h' is the accelerated moving mass 2 as shown in Figure 13.
Offset distance of the center of gravity of the upper gimbal device without 00,
'M@' is the total mass of the upper gimbal device without the accelerating moving mass 200, ax is the magnitude of the horizontal acceleration, and S is the error angle as shown in FIG.

axcolIS is a component of horizontal acceleration that tends to tilt the zorat home 300 as schematically shown in FIG. The method for calculating aX will be described next.

The vertical acceleration torque can be considered to be the same as the following equation.

h Rh ay +iinS Here, 'ay' is the magnitude of vertical acceleration, 'h' is the offset distance of the centers of gravity C and G as described above, 'Me' is the mass of the entire device as described above, and S is the mass of the entire device as described above. The error angle is as shown in . 5ins is the component of vertical acceleration that tends to tilt the plant platform 300. The method for calculating ay will be described next.

Torque due to the weight of the device can be considered using the following formula.

-Ws h 5ins where 'W1 is the total X* of the upper gimbal system without the accelerating moving mass 200. Also, 'Ws' can be substituted by the product of the mass 'Me' of the device and the gravitational acceleration 'g#.'%hI and %BI are the offset distances and errors of the centers of gravity C and G as shown in Figure 13. It is an angle. g s
in S is the component of gravity that tends to return platform 300 to a horizontal position. Wssin8 produces the same final results in the analysis described above.

The angular displacement S can be calculated as a function of time t from the following equation.

s = so + vot +%As t2 where %So
# is the initial angle at time 1=0, %yo# is time 1=
The initial angular velocity at 0, 'As', is the angular acceleration over time t.

Determination of the horizontal acceleration force generated and supplied to the jinnoul 207 is such that in the environment of the satellite antenna stabilizer installed on the ship, the pedestal 205 is moved away from the center of pitch or roll of the ship as shown in FIG. It must be taken into account that it is mounted high on spaced masts.

The maximum angle at which the ship rolls or pitches and the maximum rolling period are either specified (in this case the INMAR8AT specification is particularly relevant) or determined empirically or based on a worst case analysis.

If we take the maximum roll angle experienced by the ship as 'Tm' and express it in Asian terms (this is 30° in the INMAR8AT specifications), then the instantaneous roll angle 1T' is Tm sin
wt , where W is 2π divided by the roll period per second. The minimum roll period in the INMAR8AT specification is 8 seconds.

If the height above the center of rolling is ``H'', the horizontal distance traveled in time t is given by the following formula: ~ex=H
The -th differential of m tatami nT 'Sx' (horizontal distance traveled at time t) is the horizontal distance, and is given by the following equation.

Vx == (Tm w cos wt) Haos
T or Vx = 'I'm wl(aotl(wt
) The second derivative of eos+T8x is the horizontal acceleration aK, which is simplified as the following equation.

ax= −Tm Hw2(Tm cos2wt aln
(Tm sin (wt)) + aln (wt)
aom (Tm sln (wt) ) horizontal acceleration % ay# can be similarly determined. The instantaneous rolling angle is given by the following formula:

T = Tm alnvt The distance moved in the horizontal direction ``''SyI is given by the following formula.

Sy x= Hcog T The first derivative of 'SyI with respect to time is the velocity Svy# in the vertical direction.

My = −Tm Hw coa(wt) sin T
The second derivative of %ByI with respect to time is the vertical acceleration'
ay′.

ay = Tm ) Hw2(-Tm eoJwt eo
s (Tm sin (wt) )+ sin (wt
) ain (Tm sin (w'r) ) 1 This analysis assumes motion only in the rolling direction.

The complexity of the analysis by considering multiple movements occurring simultaneously reduces the clarity of the explanation and does not improve the final result.

This analysis attempts to explain the entities that occur, and there is no need to represent all the movements that the ship performs at the same time in the model.

Normally, the linear motion of pitching, pitching, and heaving is compared to the linear components of acceleration (tangential and vertical) acting on the antenna stabilizer as a result of pitching and rolling of the ship. Generates a very small force. Therefore, there is no need to treat this force separately.

The above equation provides a method for determining the required size of the accelerating moving mass 200. Referring to FIG. 13, the gimbal 207
By summing up the components centered at , we get the accelerated moving mass 2
00 can determine the magnitude of the correction torque that must be supplied. Gimbal 20 without acceleration moving mass 200
The total moment around 70 is given by the following formula:

Ims as c= h Ms ax cog S +
h Ms ay 5 ins - ■ h Zheng 1 ns Referring to FIG. 13, it is considered that the accelerating moving mass 200 provides a correction force R at an angle G. Therefore, the correction torque for the accelerated moving mass is given by the following equation.

-oRsin (G-8) where 'OI is the distance between the gimbal 207 and the swing point 203 of the accelerating moving mass 200.

This equation can be used to determine the amount of force 1R' required to compensate for the torque that tends to tilt the platform. This analysis can be done by computer.

The force 1R' can be determined from the sum of the moments about the center of oscillation 203 of the accelerating moving mass 200. The total moment is the product of the second-order moment of inertia and the angular acceleration at the accelerating moving mass 200. The accelerating moving mass shown in FIG. 9 can be configured as a single pendulum or a compound pendulum. axis 20
The accelerated moving mass 200 is treated as a compound pendulum in this analysis because the length of 2 is preferably shortened to improve response time.

The angle of movement of the accelerating moving mass pendulum at any point in time is expressed as a time-varying angle 'Gl. Since the dimension of the offset distance l@'0' is very small compared to the dimensions of the ship and the height of the mast H, the ax and ay of the accelerated moving mass can be considered to be the same as the ax and ay of the stabilizing pedestal, respectively, as described above. .

In this process, the angular acceleration of the accelerating moving mass i 200 is expressed by the following equation.

Here, the accelerating moving mass 200 is spherical, and the second moment of inertia of the sphere is determined as /MA r2+ MAP2, where r is the radius of the accelerating moving mass sphere, and P is the center of the accelerating moving mass sphere. Swing point 203 of accelerated moving mass
is the distance between The angle G at a certain time t is determined by the double integration of the above equation of the angular acceleration from time zero to a certain time t.

The magnitude of force 'R' is given by the following equation.

R= MA C(g-ay) eosG+BxatnG
-1 where 'MA' is the mass of the accelerated moving mass 200,
1g' is the acceleration due to gravity, Say# is the vertical acceleration,
"G# is the angle as shown in FIG. 13, and ax is the horizontal acceleration.

Force 1R' acts at angle 'G' as shown in FIG.

The formula for 'R' is a percentage to determine the mass required for the accelerating moving mass t200 to generate the desired correction force R.
You will be asked for MA#. Further, various combinations of the mass 'MA' and the offset distance 10' of the accelerated moving mass can be inserted into the equation, and a conclusion can be easily calculated by computer analysis until the most desirable combination for a given application is obtained.

The last of the four steps enumerated to obtain an advantageous embodiment of the stabilizing pedestal for use in accordance with the present invention is the step of determining the gyroscope 2090 dimensions. Gyroscope 2090 dimensions are required based on the expected operating environment of the stable antenna device.

The gyroscope 209 smooths out the transients and lowers the resonant frequency of the upper Ginnoll device.The gyroscope 209 provides a corrective force. This corrective force assists the accelerating moving mass 200 particularly during times when forces act on the platform 205 to cause the accelerating moving mass 200 to respond too quickly.

The sum of moments about gimbal 207 is typically analyzed by computer analysis of the following equation.

Ims fItI= hMs ax cog S+hM
say sin S-Wsh sin S-0Rs
in (G-8) This has already been derived and discussed. Special attention is given to the worst-case scenario or situation.

The gyroscope 209 has the expected maximum angular acceleration 1a
Dimensioned to accommodate 1. Such computer analysis can generate an amount of work that must be performed by gyroscope 209.

Gyroscope 209 provides a pair of equal torques in opposite directions that are provided in the rotor plane of the gyroscope.

Gyroscope torque is the product of the moment of inertia of a rotating mass and the angle, or the product of the rotational speed and the angular velocity of the pestle. The moment of inertia of the rotating mass of gyroscope 209 is the product of the mass of the rotor or flywheel and the square of the nodal radius.

From this relationship, gyroscope 209 is sized to accommodate the expected forces. Empirical analysis shows that the present invention has a much smaller gyroscope 20 when compared to a passively stable antenna pedestal without an accelerating moving mass 200.
9 is used.

This is very advantageous as the overall cost of the antenna stabilizer is considerably reduced. As a result, the utility of the invention is greatly increased and placed within the economic capabilities of many users. Naturally, it also contributes to society.

Gyroscope 209 also prevents redundant corrections in the presence of forward motion of accelerating moving mass 200. When displaced, the accelerating moving mass 200 responds to forward or vertical motion. Pedestal 205 does not tilt in response to forward movement. The gyroscope 209 therefore smooths the response of the accelerating moving mass to vertical motion compared to the unresponsiveness of the platform.

The dimensions of the gyroscope 209 are the product of the weight 'W8' of the upper gin noll and '''h' and the weight 'wA' of the accelerated moving mass.
and '0'. This equation has already been stated. In that case, the gyroscope 209 is small.

In some applications it is desirable to increase the correction force of accelerating moving masses. The ratio is increased to 3:1.

That is, in that case, the gyroscope 209 accelerates the moving mass 200
(There is no need to make it thicker than the movement it compensates for.

The ratio can be reduced to a point close to zero. In that case the advantage gained by including the accelerating mass t200 is reduced and the gyroscope 209 does not need to be large for correction.

From the above, the addition of gyroscope 209 to the stabilizer increases the tolerance for errors in determining the accelerating moving mass 2000 dimensions.

In some embodiments, the pedestal 300 and the mast 302
It is desirable that a spring 301 be provided between the two. This spring 301 is shifted below the center of gravity 208 by a distance Ko. Spring 301 has a spring constant K. Therefore, the spring correction moment is given by the following formula.

-K (Ko 5in (T+a)) K.

This is the spring constant '# and the distance Ko that the spring is stretched.
@In (T+@)) is the product of C and the lever arm 'Ko' that pulls the spring.

The total moment about gimbal 207 therefore includes the torque due to the spring.

-ORsin (G-8)+hMs ax cot S
+hMs ay 5ins-Wsh 5ln8-K(K
o sln (T+m)) The mass of the accelerating moving mass 200 or the dimensions of the gyroscope 209 are determined in consideration of the torque by the spring 301, as described above.

If the force tending to tilt platform 300 is sinusoidal, spring 301 reduces the amount of corrective force required from accelerating moving mass 200 and gyroscope 209. Spring 301 acts against the acceleration force applied in the horizontal direction. Spring 301 also increases the vibration period of the upper gimbal device or decreases the resonant frequency of the upper gimbal device. Spring 301 is generally useful in antennas installed on ships. Spring 301 is useless in other vehicles that move in a non-sinusoidal manner.

Spring 301 may be a torsion spring in gimbal 207. In some circumstances the cable running between the platform 205 and the ship acts as a spring 301 and contributes to stability.

The accelerating moving mass 200 illustrated in FIG. 9 is rotatably mounted within a housing 210.

This housing 210 has a conical shape with a flat mounting plate 204, which is used to accommodate the spindle date shaft 211. Housing 210 is supported on stable pedestal 205. The accelerating moving mass 200 must be provided in mechanical communication with the stabilizing pedestal 205 to provide the correcting force of the accelerating moving mass directly to the pedestal 205.

The antenna 201 is connected to the stable pedestal 205 via the altitude control device.
It is set in. This altitude control device has an altitude axis of 212
and an advanced drive motor 213. The illustrated embodiment utilizes a direct-acting advanced control system. Therefore, the antenna 201 can swing or rotate about the altitude axis 2120 to raise or lower the antenna support angle.

The antenna 201 is attached to an arm 214 as shown in FIG.
is supported by

An electronic device 215 is preferably provided at one end of the arm 214 to balance the antenna 201.

Another counterweight is attached to arm 214 for balance.

Azimuth drive motor 216 is shown in FIG.

This azimuth drive motor 216 preferably includes sprocket 2
17 and a chain 218. The chain 218 also meshes with a sprocket 219 fixed to the upper gimbal dust 220. The illustrated azimuth drive motor 216 is mounted on the pedestal 205 and thus motor 21
6 actually moves around the post 2200 when the azimuth position of the platform 205 changes.

An orientation bearing 221 is provided.

The upper gimbal structure rests on a support 222 that is part of a mast or tower.

The details of the structure for mounting the gimbal 207 are shown in FIG. The gimbal 207 has two axes that intersect with each other,
That is, it has two axes that are perpendicular to each other. A support 222 formed as a post extends through an opening 223 in platform 205. The opening 223 is large enough to hold the platform 205 in a horizontal position as the support 222 moves down the platform 205. During operation of the stability pedestal, support post 222 is displaced from its initial position, and it moves to position 222', shown in phantom in FIG. 11.

222 is displaced excessively, it hits the stopper 224 shown in FIG.
(Lotus/-) 222 is prevented from further angular displacement. The aperture 223 shown in cross section in FIG. 11 is preferably circular.

Gyroscope 209 preferably has an axis of rotation 225 where gyroscope 209 is rotatably mounted to gyroscope seat 226 .

In the illustrated embodiment, gyroscope 209 is covered by gyroscope housing 227.

The gyroscope 209 is rotatably mounted so as to be able to perform a grinding motion in accordance with the supply of a set torque to the pedestal 205. Gyroscope 209 preferably has a center of gravity slightly below pestle axis 225 to provide a vertical reference for gyroscope 209 .

In the preferred embodiment two gyroscopes 209
is used. The two gyroscopes 209 are provided so that their pestle axes are perpendicular to each other. More than one gyroscope 209 may be used if necessary. For example, four gyroscopes working in two sets can be used to the same effect.

Figure 12 shows the gyroscope 2 with the cover 227 removed.
09 is shown. Gyroscope 209 has a flywheel 228 shown in cross section. This flywheel 228 has a shaft 2 connected to a rotor 230.
Rotate on 29. This rotor 230 forms part of a gyroscope motor.

Gyroscope 209 also includes a stator 231 supported by a suitable bracket (not shown). A bearing 232 is provided to facilitate rotation of shaft 229.

When electrical energy is supplied to the gyroscope motor, the stator 231, rotor 230, shaft 229, and flywheel 228 are rotated at appropriate rotational speeds.

This speed is determined by the amount of gyroscopic correction force required for stabilization.

FIG. 4 shows another embodiment of the accelerating moving mass 67.

The mass 67 is supported in the initial position by an elastic member or a spring. The spring strips are conveniently placed relative to the support 69. In the embodiment shown in FIG. 4, the support 69 is in the form of a ring. four elastic members 68
Although shown in the figure, more elastic members 68 may be provided. The mass 67 can also be held in its initial position by means of three elastic foundations, preferably placed 120° apart from each other.

The return of the accelerated moving mass is accomplished using preloading in springs or other means.

Also, as shown in FIG. 8, the accelerating moving mass 109 can be mounted on an air bearing to reduce friction between the sliding mass 109 and the support surface 105.

The sliding material [1109] itself can be in the form of a fan or Zoroa to create sufficient airflow to support the air film as shown in FIG. It is held in the initial position by a resilient member such as spring 68. The fan or blower 110 also acts as a gyroscope for stabilization purposes. In the case of air bearings, corrosion of tonal bearings in corrosive environments is not a problem. fan 11
0 preferably has a motor 111, which motor 111
has a wing 112 rotatably attached thereto. The wings 112 have a housing 113 surrounding them, which housing 13i has one or more slots 114. The rotation of wing 112 forms an air film on which mass 109 floats above surface 105.

FIG. 5 shows a plan view of a platform 52 with four accelerating moving masses 67 of the form shown in FIG. Platform 52 is supported by a mast 70, shown in cross-section in FIG. Accelerating moving mass 67 is preferably arranged symmetrically above platform 52 about mast 70 for balancing.

FIG. 6 shows a different embodiment of the accelerating displacement mass 71 in a perspective view.

In this case, the accelerated moving mass 71 is 1! It is held in its initial position by magnetic force.

The accelerating moving mass 71 forms an electromagnet with a north pole 72 and a south pole 73.

A magnetic field is created in the accelerating moving mass 71 by a coil 74 connected to a power source or battery 75 . It will be understood by those skilled in the art that coil 74 must be oriented in a particular direction to form the desired magnetic poles represented by north pole 72 and south pole 73 of mass 71. The accelerating moving mass 71 is preferably made of a magnetic material such as iron.

The accelerating moving mass 71 is held in its initial position by a support magnet 76. Support magnet 76, shown in cross-sectional perspective view, is magnetized by a coil 79 or series of coils, which is connected to a power source or battery 80. The coil 79 has a support magnet 76 with north poles 77 and south poles corresponding to north poles 72 and south poles 73 of the accelerating moving mass 71, respectively.
It is wound so as to have a pole 78.

Based on the magnetic principle, poles 77 and 72 of the same polarity repel each other, and similarly poles 78 and 73 repel each other. When the support magnet 76 is preferably configured in the form of a circle or a ring, the support magnet 76 tends to resiliently bias the accelerating moving mass 71 towards an initial position approximately at the center of the support magnet 76 . However, if the linear acceleration force tends to accelerate the support magnet 76 that is originally mechanically connected between the antenna devices, the inertia of the mass 71 overcomes the magnetic force in this embodiment, allowing the mass 71 to move.

FIG. 7 shows an example between antenna devices using another example of an accelerating moving mass 85. The antenna arrangement preferably has a center of gravity (not shown) located slightly below the gimbal joint 53. The position of the center of gravity can be adjusted by changing the counterweight 100. antenna 5
1 is supported by a mast 70. Acquisition of satellite targets is accomplished by an altitude drive 92 that rotates the antenna about an altitude axis 810 and an azimuth drive 93 that rotates the antenna about an envelope axis 820.

Mast 70 is maintained in a fairly stable orientation by the action of stabilizing platform 52 and the pendulum action of the shift of the center of gravity on the underside of gimbal 53. The gimbal 53 preferably has a first gimbal axis 83 and a second gimbal axis 84 perpendicular to the axis 83. Mutually orthogonal gimbal axes 83 , 84 are preferably located in a horizontal plane defining gimbal joint 53 . This gimbal structure is similar to a U-joint like those used in power vehicles.

Stability platform 52 preferably has one gyroscope 61. This gyroscope 61 has a gyroscope motor 62 and a gyroscope rotor 63. The motor 62 rotates the rotor 63 at a high speed to perform a gyroscopic action. Gyroscope 61 is preferably supported by platform 52. Two gyroscopes 61 can be provided, and these gyroscopes are rotatably provided so that their axes are orthogonal to each other. The rotation allows the gyroscope 61 to perform a grinding motion about its axis of rotation. When two or more gyroscopes 61 are used, they are placed so that the center of gravity is below the axis of rotation so that gravity tends to bias the gyroscopes 61 vertically. It can also be considered a pestle limiter. Each gyroscope 61 is provided above or below the platform 52. Gyroscope 61 can be tilted alternately in non-vertical positions. In such cases it is preferable to tilt the gyroscope 61 in a symmetrical arrangement.

The acceleration movement 't85 compensates for the unstable force due to linear acceleration. The accelerating moving mass 85, shown in cross-section in FIG. 7, is in the form of a ring, or in other words a cylinder. Accelerating moving mass 85 is supported by support housing 87 . The mass 85 is free to slide horizontally within the support housing 87. For example, in FIG. 7, the accelerating moving mass 85 is free to slide from side to side within the support housing 87. Although FIG. 7 is a quadratic drawing, the accelerating moving mass 85 is also free to slide in the front and back directions of the page and in all directions in between. That is, the accelerating moving mass 85 is preferably free to move 360° in a horizontal plane.

The housing 87 has an opening 104 through which the mast 70 passes, supporting the support 57 and the mass).
70 gimbals 53 are allowed to move freely relative to each other. The support housing 87 is preferably of quality i'
It has a lower surface 88 coated with Teflon to facilitate sliding of 85. Similarly, the lower surface 89 of platform 52 is coated with Teflon. The sliding mass 85 can also be coated with Teflon and the lower surface can be glass or polished metal.

The mass 85 is supported on three or more legs, the bottoms of which may be Teflon coated.

The accelerating moving mass 85 is held in the initial position by an elastic member 86. Elastic member 86 is a spring. The accelerating moving mass 85 may also be held in the initial position by electromagnetic devices, electrostatic forces, hydraulic devices, or other devices apparent to those skilled in the art.

Azimuth drive device 93 is provided on the gimbal plane or gimbal joint 53. This is important because if the azimuth drive is located below gimbal 53, pointing errors will occur.

There is no need to connect platform 52 directly to antenna 51. In the illustrated embodiment, the platform 52 is a square 70 on which the antenna 51 is mounted.
Stabilize the direction of. Platform 52 is thus mechanically connected to antenna 51 via mast 70.

Stability of the platform 52 attempts to stabilize the antenna 51 and to keep the orientation of the antenna 51 constant during pitching and rolling movements of the ship or platform on which the support 57 is mounted.

Connection of the antenna 51 with the satellite receiver by means of a slip ring is undesirable and is not suitable for the entire device (INM
(See AR8AT specifications). Therefore, it is often necessary to quickly adjust the azimuth setting of antenna 51 (eg, by rapidly rotating antenna 51 about azimuth axis 82) in order to untangle the cable. As platform 52 rapidly flips, gyroscope 6
Try to make 1 unstable. In the embodiment shown in FIG. 7, there is no need to rotate platform 52 when the orientation of antenna 51 is changed.

Platform 52 is preferably rotatably disposed on mast 70. A ring bearing 91 is provided to facilitate rotation of platform 52 on mast 70. Since friction is present in the bearings 91 in most practical systems, it is desirable to provide a platform azimuth drive mechanism for use in rotating the platform 52 about the mast 70. In the preferred embodiment, the platform drive 90 follows the vessel's compass direction, so that if the vessel changes its heading, the orientation of the platform 52 is changed by the drive, and the platform 52 remains approximately constant in orientation with respect to the compass direction. It is in. In reality, the ship turns downward between the antenna devices, but the antenna devices remain almost stationary.

The platform drive (a) is connected to the mast 70 by a gear 97.

Stepper motors are preferably used for the altitude drive 92 and the azimuth drive 93. The use of a stepper motor is very advantageous because the residual torque due to the permanent magnetic field of the stepper motor only takes on the necessary forces on the altitude and azimuth axes when the bow changes or the ship moves away. In many installations, these conditions rarely occur, and therefore the pedestal is in an undriven state with almost no power during the period of use. Another advantage is that when a conventional Sir2 control drive goes down a hole due to actual loss of power, the use of the step motor attempts to maintain the final set altitude at the azimuth position set before the loss of power, thereby Maintaining useful communications for very long periods when the bow is maintained between several positions.

Conventional serze motors whose commutator discharges are environmentally acceptable are used for the altitude drive 92, azimuth drive 93, and platform drive (a).

Another embodiment of the present invention utilizes celsyntorque at the gyroscope 61 location. This eliminates the very expensive gyroscope and replaces it with two small components that are relatively inexpensive.

The selection and adjustment of the components of an accelerated moving mass of the type shown in Figures 4 through 8 takes into account that linear acceleration produces a pitching moment, torque, or both on the platform based on the following equations: will be carried out.

ML = I) rntaL where Mt, AJ' Pitching moment D of the linear accelerator
is the offset distance between the gimbal and the center of gravity of the antenna platform, mt is the total mass of the antenna platform, and aLA is the linear acceleration component.

The offset moment generated by the accelerating moving mass is given by:

MD, W "dm g where MDM is the offset moment due to the accelerating moving mass, X is the C0G offset distance (see Figure 3), mDM is the mass of the accelerating moving mass, and g is the gravity.

In the embodiment shown in FIG. 4, the offset distance X is given by the following equation in relation to the spring constant k.

It is desirable to determine the accelerated moving mass at rrIDMILLA X=- as follows. That is, MLA=MDM or this relationship is used to determine the resiliency constant and desired mass.

When the single resonant frequency of the accelerating moving mass and the combination of springs are important, the general formula for the calculation is obtained by considering the following relationship.

F = ma (force = quality x acceleration) Qc = "DM aLA aLm = 78 INMAR8AT specifications and specifications for special antenna applications are of particular interest, e.g. INMAR-8A
The T specification specifies that the acceleration introduced into the upper deck equipment is 0.5.
It points out that it has a maximum tangential acceleration less than g and must withstand a rolling motion with a period of 8 seconds, a pitching motion with a period of 6 seconds, and a rocking motion with a period of 2 seconds.

Therefore, in this INMAR8AT specification, the fastest excitation effect is 1/(6 seconds) or 0,167 H+c.

For example, if the antenna device has the following parameters: (total weight on gimbal) wl, A = 220
Pound D = 0.4 inches x -6.0 inches (max) f50Hz The following calculation is obtained.

”0M2-mLAD g
(seconds/period) These relationships and their examples can be used to construct special antenna pedestals with accelerating moving masses.

The above disclosure of the preferred embodiments of the invention is provided to inform those skilled in the art how to make and use the invention. Another disclosure is Albert HDi@s
U.S. Patent No. 3,893,123 (title of invention 'Combination Gyro and
PendulumWeight 5tabilize
d Platform Antenna System
'And the title of the invention of U.S. Patent No. 4020491 invented by Mr. Alb@rt HBl@w@r et al.' Co
mblnation Gyro and Pendu-
1um Weight Pa5sl vs Ant@nna
Platform Stabilizat1onSy
mtsm', and the specifications of both are cited as reference examples of the present invention.

It goes without saying that the present invention may be modified in various forms without departing from the spirit and scope of the invention. The scope of the invention is not limited to the illustrated embodiments, but includes all modifications that fall within the scope of the claims.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view of an antenna arrangement mounted on the top of a mast or tower on a ship; Fig. 2 is a schematic side view of the antenna arrangement on a ship; Fig. 3 is a schematic diagram of the shape of the accelerating moving mass and the stabilizing platform. 4 is a perspective view of different embodiments of accelerating moving masses, FIG. 5 is a plan view of a stable platform with four accelerating moving masses of the type shown in FIG. 4, and FIG. 6 is a perspective view of different embodiments of accelerating moving masses. FIG. 7 is a rear view of an antenna mounted on a stable platform and having an accelerating moving mass of a different embodiment;
FIG. 8 is a perspective view of yet another embodiment of the accelerating moving mass;
9 is a rear view of the antenna device mounted on the stability pedestal and has a preferred form of accelerating moving mass; FIG. 10 is a plan view of the stability pedestal taken along line 10--10 in FIG. 9; The figures are a sectional view of the gyroscope mounting device and platform mounting of the embodiment shown in FIGS. 9 and 10, and FIG. 12 is a sectional side view of the gyroscope shown in FIG. 11. FIG. 13 is a schematic explanatory diagram of a pedestal provided on a ship's mast. Seki...Antenna, 52...Platform, Group...
・Gimbal, familiarity...tower, 55...ship, fleet...ship's pitching center, 61...gyroscope, 65...
Accelerating moving mass, 66... Spring, 67... Accelerating moving mass, Kaku... Spring, 70... Mast, 71... Accelerating moving mass, 85... Accelerating moving mass, 87... Support housing, 93... Orientation drive device, 109...
Accelerated moving mass, 200... Accelerated moving mass, 201...
・Gimbal joint, 205...Platform. Applicant's agent Kiyoshi Inomata (71)

Claims (1)

[Scope of Claims] l] A stable platform used in connection with a satellite antenna provided on a ship, the platform being provided on a gimbal joint used for supporting the platform on the ship; During rocking and rolling motions, the platform is mechanically connected and an accelerating moving mass is provided to compensate for the linear acceleration, and this accelerating moving mass returns to its initial position in the absence of linear acceleration, and the platform and accelerating moving mass and the antenna constitute a statically balanced structure when the accelerating moving mass is in its initial position, this structure has a center of gravity located on the underside of the gimbal joint, and the accelerating moving mass destabilizes the platform. acting to reduce the force due to linear acceleration which tends to cause the accelerated moving mass to be displaced from said initial position in response to the linear acceleration of the structure formed by the platform, the accelerated moving mass and the antenna. The accelerated moving mass unbalances the gravitational force acting on said structure as it moves to its displaced position such that the unbalanced gravitational force attempts to offset the unstable force due to linear acceleration. It has an accelerating moving mass characterized by stable platform. 2) A stable platform according to claim 7, characterized in that it comprises a gyroscope, the gyroscope being mechanically connected to the platform such that the resistance of the gyroscope to displacement stabilizes the platform. Baume. 3) having two gyroscopes, the seventh gyroscope being rotatably mounted on the second axis, the second gyroscope having a first axis substantially perpendicular to the axis of the first gyroscope; according to claim 7, characterized in that the seventh and second gyroscopes are rotatably mounted on the axis of the platform and the seventh and second gyroscopes are mechanically connected to the platform so as to stabilize the platform. Stable platform listed. Claim 3 characterized in that the axis of the seventh gyroscope runs substantially parallel to the plane of the platform and the axis of the second gyroscope runs substantially parallel to the plane of the platform. Stable platform described in. The center of gravity of the statically balanced structure is about the bottom of the gimbal joint when the accelerating moving mass is in its initial position;
Stable platform according to any one of claims 7 to 1, characterized in that it is at the point jcojIII+. t) the structure is initially statically balanced with an initial center of gravity coincident with a substantially horizontal plane passing through the gimbal, and the structure has a counterweight mechanically connected to the structure; 6. A stable platform according to any one of claims 1 to 5, characterized in that the combined center of gravity of the balanced structure and counterweight is located below the gimbal joint. 7) The accelerating moving mass is elastically positioned such that the accelerating moving mass tends to return to its initial position in the absence of linear acceleration, and as the accelerating moving mass returns to its initial position, this accelerating moving mass interacts with the platform 7. A stable platform according to claim 7 and any one of claims 3 to 6, characterized in that the structure formed from the moving mass and the antenna is brought back into balance. 'lr) according to claim 7 or any one of claims 3 to 7, characterized in that the accelerating moving mass consists of a pendulum rotatably supported on a platform on a gimbal joint. stable platform. Stable platform according to claim 1, characterized in that a pendulum of mass is supported by a very short arm rotatably connected to the platform. Claims characterized in that the accelerated moving mass of l has a pendulum period that is at least 10 times shorter than the secondary pendulum period of the platform and all structures supported by this platform. Stable platform as described in section. 7) In a stable antenna platform for use in conjunction with equipment subjected to pitching and rolling motion, the platform is rotatably mounted on a substantially vertically oriented mast, and a gimbal prevents the mast from pitching. and to a support placed above the equipment that is exposed to rolling motion, and the antenna is mechanically connected to the platform so that the stability of the platform is maintained during pitching and rolling motions of the equipment. Attempts to stabilize the antenna and maintain the antenna's pointing in a generally constant direction, the platform supports at least λ gyroscopes rotatably mounted on mutually orthogonal axes, and the accelerating moving mass is placed on the mast. The platform, the antenna, the gyroscope, and the accelerating moving mass form a structure in which the accelerating moving mass is used to compensate for the forces generated by linear acceleration. It is approximately balanced and has a center of gravity located slightly below the gimbal, and this center of gravity is located approximately above the vertical axis passing through the gimbal when the accelerating moving mass is in its initial position with no linear acceleration, and the acceleration The moving mass has an initial position and the accelerating moving mass is capable of moving to a displaced position spaced from its initial position in response to linear acceleration of the structure, such that the accelerating moving mass offsets the destabilizing forces due to the linear acceleration. A stable antenna platform characterized in that it moves the center of gravity of a structure and unbalances the gravitational force acting on the structure, and returns to a position where the accelerating moving mass restores balance to the structure in the absence of linear acceleration. 7.2) A platform is used to rotate around the mast, and this platform can maintain approximately the same orientation if the device rotates, so that the device can rotate without destabilizing the platform. Stable antenna platform according to claim 1, characterized in that: 13) A patent claim characterized in that the acceleratingly moving mass consists of a slidable ring supported by a support nozzle and has an elastic device biasing the acceleratingly moving mass in the direction of its initial position. The stable antenna platform according to range 1/ or 1j. 14. A stable antenna platform as claimed in claim 13, characterized in that the glue elastic device consists of a plurality of springs. tj) Stable antenna platform according to claim 13, characterized in that the elastic device consists of an electromagnet. /6) The accelerating moving mass consists of a mass with a plurality of springs arranged against the mass to bias the mass to its initial position, and these springs also arranged against the platform. A stable platform as claimed in claim 1, characterized in that the platform has: /7) The accelerating moving mass is supported on air bearings to reduce friction between the accelerating moving mass and the surface supporting the accelerating moving mass. The stable antenna platform according to paragraph 1 or paragraph 1. /r) any one of Claims 1 and 17, characterized in that the position-adjustable counterweight is supported by a platform for adjusting the position of the center of gravity of the structure. Stable antenna platform as described in . 1. Stabilizer according to claim 1, characterized in that the accelerating moving mass consists of a pendulum rotatably supported on a platform on a gimbal joint. platform. 12. Stable platform according to claim 11, characterized in that a pendulum of λ is supported by a very short arm rotatably connected to the platform and consists of a mass of 5. 2) The accelerated moving mass has a pendulum period that is at least 5 times shorter than the secondary pendulum period of the platform and all structures supported on this platform. Stable platform as described in Section 1I. 22) A stable antenna device for use in connection with a support that is subjected to pitching and rolling motion, the antenna device having a gimbal joint, the antenna device being supported on the support, and the support being connected to the gimbal joint. the antenna device is suspended so that the antenna device remains level when the support is moved over the gimbal joint, the antenna device is substantially balanced, and has a center of gravity located slightly below the gimbal joint; An accelerating moving mass is supported by the antenna device, the accelerating moving mass is utilized to compensate for forces generated by linear acceleration of the antenna device, the accelerating moving mass has an initial position, and the accelerating moving mass has an initial position of the antenna device. By moving to a displaced position away from its initial position in response to linear acceleration, the accelerating moving mass moves the center of gravity of the antenna device to offset the unstable forces due to linear acceleration and the gravity acting on the antenna device. A stable antenna device characterized in that the accelerating moving mass returns the antenna device to an initial position to restore balance in the absence of linear acceleration. Stable antenna arrangement according to claim n), characterized in that the accelerating moving mass is supported on air bearings to minimize friction between the accelerating moving mass and the antenna arrangement. J) Stable antenna arrangement according to claim 1, characterized in that it comprises an elastic device biasing the acceleratingly moving mass towards its initial position. Stable antenna device according to claim 1, characterized in that the elastic device consists of a plurality of springs arranged between the antenna device and the accelerating moving mass. , 26) Stable antenna device according to claim 3, characterized in that the elastic device consists of an electromagnet employed to create a magnetic field biasing the accelerating moving mass in the direction of its initial position. . , 27) characterized in that the center of gravity of the statically balanced structure is within the range of O, to o, r inches away from the underside of the gimbal joint when the accelerating moving mass is in its initial position. Claims 1, r, 1/1, and 7.
Stable platform according to any of clauses 2 and 19. d) The accelerating moving mass has a pendulum length, and the accelerating moving mass is accelerating the product of the weight of a statically stable structure (less than the weight of the accelerating moving mass) and the offset distance of the center of gravity. 28. A stable platform as claimed in claim 27, having a weight slightly less than the mass divided by the pendulum length. Claims 7 to 3, characterized in that the accelerating moving mass has a resonant frequency, and the platform has a composite resonant frequency that is at least plo times smaller than the resonant frequency of the accelerating moving mass. A stable platform as described in any of the above.