JPH10239446A - Earthquake observing posture control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a mechanism so as to be easily manufacturable and easily posture-controllable. SOLUTION: In an earthquake observing posture control device posture- controlled according to the inclination of a landed bottom surface, it has a pressure resisting vessel inner housing 1 having a fixed angle range to the long axial direction of a pressure resisting vessel 8 and having a spherical inside surface around the long axial line, a seismograph body 2 housed within the housing 1 and having a center-of-gravity position set closer to the just under from the central position, at least three or more ball bearings 3 making contact with the spherical inside surface of the housing 1 provided on the body 1 at equal intervals, and a control means 5 having a mode of rotating the bearings 3, a mode of laying them in free state, and a mode of laying them in clamp state. The bearings 3 are covered with films 4 having a frictional coefficient of about 0.5 or more, the bearings 3 are laid in free state to posture- control the seismograph body 2, and the bearings 3 are laid in clamp state to fix the posture of the seismograph body 2 for observation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic observation attitude control device which is housed in a pressure vessel and whose attitude is controlled in accordance with the inclination of a landing surface.

[0002]

2. Description of the Related Art Conventionally, a seismic observation network limited to a land area is not enough to elucidate a mode of occurrence of a large earthquake in a plate subduction zone. For this reason, it is necessary to constantly observe microseismic activity on the sea floor near the subduction opening of the ocean plate such as the Japan Trench. For this reason, a cable-type ocean bottom seismic observation device is generally installed on the sea floor with a non-zero inclination angle, for example, in order to grasp the physical process of the occurrence of a large earthquake due to such subduction of the ocean plate. In such a cable type observation device, several seismic observation devices are connected in series by a transmission cable, operated by power supply from the land, and the obtained data is transmitted to the central station on the land by the transmission cable. .

FIG. 7 is a diagram showing a configuration example of this type of conventional seismic observation device for installation on the sea floor, and FIG. 8 is a configuration diagram schematically showing a conventional attitude control device provided in the device. FIG.
As shown in the figure, the seismic observation device that has landed on the sea floor whose long axis h is inclined with respect to the horizontal plane H has a pressure vessel 2
1 houses a seismometer 22, a signal transmission unit 23, a power supply, and the like. In such an earthquake observation device, the pressure vessel 2
Regardless of the state in which 1 is installed on the slope, seismometer 2
In order to enable the three-component detectors of No. 2 to operate normally in the normal posture, the apparatus includes a posture control device that mechanically controls the posture. The attitude control device has a function of fixing the seismometer 22 to a container and protecting the seismometer 22 in order to protect the seismometer 22 from vibration and impact during transportation and installation work.

[0004] The operation principle of the above-mentioned conventional attitude control device is as described below. That is, as shown in FIG. 8, the outer gimbal 31 and the inner gimbal 32 are rotatably supported on a perpendicular axis in the container 30 in the pressure-resistant container 21. The outer rotating shafts 33, 33 and the ball bearings 34, 34 support the outer gimbal 31 on the pressure-resistant container 30 so that the outer gimbal 31 can rotate about the horizontal axis X in the drawing.
Then, the inner rotating shafts 35, 35 and the ball bearing 3
6 and 36, the inner gimbal 32 fixing the seismometer is supported by the outer gimbal 31 so that the seismometer can be rotated about the illustrated vertical axis Y. In such an attitude control device, high-precision bearings 34, 34, 36, and 36 are used for the rotating shaft in consideration of impact resistance. When the clamp function of the outer gimbal 31 and the inner gimbal 32 of the attitude control device of the observation device is released after being installed on the seabed inclined surface, the horizontal attitude is passively obtained by the action of gravity. When the posture is stabilized, the outer gimbal 3 of the posture control device
1 and the inner gimbal 32 are clamped to be in an observation state.

However, in the above-mentioned attitude control device, since the attitude control mechanism is complicated, high machining accuracy is required for components of a rotation mechanism such as a ball bearing in order to obtain a high-precision horizontal attitude. And advanced technology is required. Therefore, there is a problem that the number of skilled persons who can produce a product satisfying the specifications is small and the cost is high. Further, the principle of the attitude control has a problem that the action of gravity is only used passively.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an attitude control apparatus for earthquake observation which simplifies an attitude control mechanism, can be easily manufactured, and easily controls an attitude.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to simplify a posture control mechanism, facilitate manufacture, and facilitate posture control. Therefore, the present invention is housed in a pressure-resistant container,
An attitude control device for earthquake observation, the attitude of which is controlled in accordance with the inclination of the landing surface, which has a cylindrical inner peripheral surface, and a vertical axis of the inner peripheral surface, which is orthogonal to a long axis of the pressure-resistant container, is centered. The sandwiched area of a certain angular range is formed in a pressure-resistant container inner housing formed in a spherical shape with the intersection of the long axis and the vertical axis as a center of rotation, and the spherical inner peripheral surface of the pressure-resistant container inner housing. A seismometer body that is opposed to a gap, and whose center of gravity is set just below the center position, and provided on the seismometer body,
At least three or more ball bearings abutting at equal intervals on the spherical inner peripheral surface of the pressure-resistant container inner housing, and a mode in which the ball bearings are driven to rotate, in a free state, and in a clamp state. The ball bearing is covered with a film having a coefficient of static friction of about 0.5 or more in a dry state at room temperature.

[0008] The control means may include a motor,
A motor that drives the motor to rotate the ball bearing in a mode in which the motor is driven to rotate based on the detection signal of the inclinometer; and the film has an elastic modulus (Young's modulus) at room temperature. Is a hard film having a ratio of 1 × 10 ⁻³ N / m ² or more and 1 × 10 ¹⁰ N / m ² or less, and a clamp pin for clamping the seismometer body is provided in the pressure-resistant container housing. It is assumed that.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are views showing an embodiment of an attitude control device for earthquake observation incorporating three ball bearings according to the present invention, and FIG. 1A shows the attitude control device for earthquake observation of FIG. 1B is a cross-sectional view taken along a line connecting the center C and the center C, and FIG. 1B is a cross-sectional view taken along a vertical axis v of the pressure-resistant container shown in FIG. FIG. 2 is a view showing the cross section taken from the direction of arrow S in FIG. 1A, and FIG. 2 is a flowchart showing a flow of a procedure for controlling the attitude of the attitude control apparatus for earthquake observation of the present invention.
FIG. 2 is a view showing a state of the seismometer main body 2 after attitude control when the housing 1 in the pressure-resistant container shown in FIG. Here, reference numeral 1 denotes a pressure-resistant container housing provided in a cylindrical pressure-resistant container 8; 2, a seismometer main body; 3, a ball bearing; 4, a hard rubber film made of a polymer material; The micro motor or the step motor 7 indicates a clamp pin.
In addition, the above-mentioned pressure vessel 8 is a vessel having a structure configured to withstand water pressure in an environment where hydrostatic pressure is applied, such as a sea bottom, a lake bottom, or an excavation pit, or a harmful gas,
It refers to a container having a structure that protects a housing device such as a seismometer or an electronic circuit in the container for a long period of time even in a bad environment where a fluid or the like exists.

As shown in the cross-sectional view of FIG. 1A, both sides of a vertical axis v at an intersection C between a long axis h of the pressure-resistant container inner housing 1 and a vertical axis v orthogonal thereto are more than ± 45 °. At an angle, the entire peripheral surface of the inner peripheral surface region of the pressure-resistant container inner housing 1 sandwiched by the lines m ₁ and m ₂ crossing and passing through the intersection C is:
In FIG. 1 (A), by drawing a sphere centered on the intersection C of the long axis h of the pressure-resistant container inner housing 1 and a vertical axis v orthogonal thereto, as shown by the solid line, the inner peripheral surface area Are formed in a spherical shape in the direction around the major axis h and in the circumferential direction.

Then, both end faces are formed substantially flat,
The seismometer main body 2 whose outer peripheral surface has a spherical shape corresponding to the spherical inner peripheral surface of the pressure-resistant container inner housing 1 has a spherical inner peripheral surface of the pressure-resistant container inner housing 1 with the spherical outer peripheral surface interposed therebetween. The seismometer main body 2 is rotatably supported between a spherical inner peripheral surface of the housing 1 and a spherical outer peripheral surface of the seismometer main body 2. .

The ball bearing 3 is used for the seismometer main body 2.
Micro motor or step motor 5 built in
As shown in FIG. 1 (A), it is on a vertical axis v passing through the seismometer main body 2 in two equal parts, and as shown in FIG. 1 (B), At least three or more are arranged at regular intervals around the axis of the long axis h of the in-container housing 1, and the surface thereof is hard film having a coefficient of static friction of about 0.5 or more in a dry state at room temperature, for example, , A hard rubber film or a synthetic resin film 4
Alternatively, the attitude can be controlled by freely rotating by the stepping motor 5, or it can be fixed in a friction clamp state, and further, the ball bearing 3 can be released to be in a completely free state. It has become.

As described above, when the ball bearing 3 is in the free state, the seismometer main body 2 is supported to rotate on the spherical inner peripheral surface of the pressure-resistant container inner housing 1 by the action of gravity. As shown in FIGS. 1A and 1B, a center of gravity G is set at a point away from the rotation center C. For this reason, when the ball bearing 3 is released to be in a free state, the seismometer main body 2 moves due to the action of gravity.
It rotates freely and stabilizes in a posture in which its center of gravity G is located directly below the center C. Therefore, the pressure vessel 8, in other words,
The housing 1 in the pressure vessel is 360 ° around the axis of the long axis h
Even if the seismometer main body 2 rotates freely by the ball bearings 3 even if it rotates, or the long axis h is inclined to the left and right sides within ± 45 ° about its vertical axis v, as shown in FIG. As shown in the drawing, the posture can be passively controlled by the gravity action so that the center of gravity G is located immediately below.

Further, the inclinometer is built in, and the ball bearing 3 is driven by driving the micromotor or the step motor 5 using the inclination data in the direction around the major axis h and the inclination direction of the major axis h. Rotate and control the attitude of the seismometer main body 2 so that the output of the inclinometer becomes 0,
The posture can be finely adjusted actively.

As shown in FIG. 1A, the clamp pins 7, 7 are advanced by a micromotor or a step motor 6, 6 provided outside the bottom wall located on the right side of the housing 1 in the pressure-resistant container in the drawing. The seismometer main body 2 is fixedly placed in the pressure-resistant container inner housing 1 so as to be able to withstand vibration and shock applied during transportation and installation, and is configured to be retracted, and a micromotor or As shown in FIG. 1A, the crankpins 7, 7 locked to the seismometer main body 2 are retracted by the stepping motor 6 to the unlocked state shown in FIG. Can be released.

Next, the control operation of the above-described attitude control apparatus for seismic observation according to the present invention from transport to installation to seismic observation will be described with reference to a flowchart shown in FIG. First, during transportation and installation from shipping to landing on the seabed, the ball bearing 3 is brought into a friction clamp state by a micromotor or a step motor 5, and as shown in FIG. The seismometer main body 2 is fixed to the pressure-resistant container inner housing 1 by the clamp pin 7 so as to withstand vibration and impact. FIG.
As shown in FIG. 1, it is determined whether or not the vehicle has arrived on the inclined surface (step S11). When it is determined that the vehicle has arrived on the inclined surface, the vehicle is settled and laid on the inclined seabed, and then shown in FIG. The locked crank pin 7 is retracted from the seismometer main body 2 by the micromotor or the stepping motor 6 to release the locking and release the fixing (step S12), and the micromotor or the stepping motor 5 Makes the ball bearing 3 free (step S1)
3). As a result, even if the observation device installation surface is inclined,
In accordance with the inclination of the housing 1 in the pressure-resistant container in the direction of the long axis h and the rotation around the axis of the long axis h, the seismometer main body 2 causes the center of gravity G to be located directly below the housing 1 in the pressure-resistant container by the action of gravity. As described above, the robot is passively rotated, and a certain horizontal posture is automatically obtained. Further, the detection signal of the inclinometer is taken in (step S14), and it is determined whether or not the seismometer main body 2 has obtained a complete horizontal posture (step S15). The micromotor or the step motor 5 is actively driven based on the detection signal of the inclinometer to perform fine adjustment of the attitude (step S).
16). After the posture is stabilized in this way, the ball bearing 3 is again set to the friction clamp state by the micromotor or the step motor 5 (step S17), and the observation state is set, and the earthquake observation is started (step S18). . FIG. 3 shows that the pressure vessel of the attitude control device for earthquake observation incorporating three ball bearings 3 has an inclination angle of 4 degrees.
FIG. 7 is a vertical sectional view showing a stable state of the seismometer main body 2 which has completed the attitude control as described above even when landing at 5 °. When the horizontal posture is obtained in step S15, it goes without saying that the process jumps to step S17 described above.

Next, if the pressure vessel 8 moves and the horizontal attitude of the seismometer main body 2 cannot be obtained after the observation state, the micromotor or the step motor is again readjusted to adjust the attitude. 5, the ball bearing 3 is set in a free state, or a horizontal attitude can be obtained by driving a micromotor or a step motor 5 based on a detection signal of an inclinometer. Ball bearing 3 described above
The surface is covered with a polymer material 4 such as a hard rubber film, so that the seismometer main body 2 is fixed in the pressure-resistant container housing 1 in a friction clamp state, or the posture is finely adjusted by a micromotor or a step motor 5. The adjustment can be made active. As described above, in addition to the passive attitude control of the seismometer main body 2 of the present invention, the active attitude control can be performed so that the output of the inclinometer becomes zero. This method has an advantage that it may be reduced as compared with the method described above.

FIG. 4 to FIG.
9 shows another embodiment of the attitude control device for earthquake observation according to the present invention, in which the present invention is incorporated. FIG. 4 shows the state shown in FIG.
5A is a cross-sectional view taken along the vertical axis v of FIG. 5, viewed from the direction of the arrow U (the direction of the long axis h) in FIG.
(A) is a cross-section of the seismometer main body 2 cut along a straight line connecting the center of gravity G and the intersection C in FIG. 4, arrow T direction (direction perpendicular to the long axis h direction)
FIG. 5B is an oblique external view of the seismometer main body 2 shown in FIG. 5A.

FIG. 6A shows a state before the attitude control of the seismometer main body 2 when the pressure-resistant vessel 8 is settled down in the direction of the long axis h, and FIG. 6B shows a position state after the attitude control. FIG. 6 (C) is a cross-sectional view showing the state in which the pressure-resistant container 8 has landed on a plane inclined in a plane perpendicular to the long axis h direction, that is, FIG.
(D) shows a state before attitude control in which the center of gravity G is rotated by 90 ° about the axis of the long axis h in FIG. 5 (A), and FIG. It is sectional drawing which respectively shows.

As shown in FIG. 5A, when the seismometer main body 2 is formed in a polygonal cross section (octagonal shape), it has the following specific shape. That is, as shown in FIG. 5 (A), the straight line e ₁ of the pressure-resistant container inner housing ₁ ,
Each section cut along e ₂ , f ₁ , and f ₂ and viewed from the long axis h direction (the direction of the arrow U) has a circular area. The portion surrounded by the straight lines e ₁ and e ₂ sandwiching the vertical axis v has, for example, a cylindrical shape, and as shown in FIG. 5B, both end surfaces of the cylindrical body, that is, the straight line e.
₁ and e ₂ as the bottom surface, and the straight line f ₁ ,
The truncated cones k ₁ and k ₂ having a circular area with the top area at f ₂ are formed continuously and integrally with the above-mentioned cylindrical body, and have the shape shown in FIG. 5B. As shown in FIG. 4, the ball bearing 3, the micromotor, or the step motor 5 that supports the seismometer main body 2 having the above-described shape forms a straight line connecting the center of gravity G of the seismometer main body 2 and the center C thereof. It is symmetrically shifted by ± 60 ° to both sides, and two pieces are arranged at an interval of 60 °. Of course, the ball bearing 3 is covered with a film having a large coefficient of friction, that is, a film having a coefficient of static friction of about 0.5 or more in a dry state at room temperature.

By arranging in this manner, the horizontal housing 1 shown in FIG.
As shown in the figure, when the seismograph main body 2 is landed on the sea floor with inclination, the center of gravity G of the seismometer main body 2 is maintained in a state of being displaced to the right of the vertical line w in the figure. When the ball bearing 3 is set to the free state mode before the attitude control,
As shown in FIG. 6B, the seismometer main body 2
When the center of gravity G rotates in the direction of the arrow in the figure and is positioned vertically below the vertical line w, the center of gravity returns passively, whereby the seismometer main body 2 is in a state in which the posture is controlled.

Next, as shown in FIG. 4, the pressure vessel housing 1 in which the center of gravity G of the seismometer main body 2 is located vertically below the vertical line w is moved from the state of FIG. G
However, as shown in FIG. 6C, 90
° Assume that the player has landed while turning. Ball bearing 3
Is set to the free state mode, as shown in FIG. 6 (D), the seismometer main body 2 is driven by gravity so that the center of gravity G rotates in the direction of the arrow in the figure and is positioned vertically below the vertical line w. Then, the seismometer main body 2 is in a posture-controlled state. In this modified example, as shown in FIG.
Is separated by an angle of ± 60 ° on both sides of the line connecting the two and the two are arranged symmetrically with respect to each other with a 60 ° angle therebetween. ,
Seismometer body 2, since the ball bearing 3 is rotationally displaced so as to draw a locus of a circle O ₂ of smaller diameter than the circle O _1, spherical inner surface of the pressure-resistant container housing 1, circular to Nagajikusen h direction O It can cope with n ₁ ~n ₂ width of _1. In this modification, as described above,
It goes without saying that the attitude control is actively performed so that the output of the inclinometer becomes zero.

Although the attitude control apparatus for seismic observation described in the above embodiment has been described as being installed on the sea floor, the present invention is not limited to this. Of course, it can be installed on a non-horizontal slope to observe seismic motion.

Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example,
In the above embodiment, the ball bearing is connected to the seismometer main body 2.
Although three or four are provided at equal intervals around the area, it is needless to say that the number may be further increased. In such a case, one that controls the direction driven by the micromotor or the step motor in the direction of inclination of the long axis h and one that controls the direction of rotation of the long axis h may be provided. The shape of the seismometer main body 2 is not limited to a rotating body having an axis in the long axis h direction as long as the above-described embodiment is possible. Further, in the pressure-resistant container inner housing 1, the axial inclination of the spherical inner peripheral surface is ± 4 as shown in FIG.
Although it was made possible to cope with up to 5 °, it may be enlarged so that it can follow even a larger inclination angle. The hard rubber film may be made of another material as long as the material is a thin film having a coefficient of static friction in a dry state at room temperature of about 0.5 or more. Furthermore, in order to remove deformation error, a ball bearing, the elastic modulus at room temperature (Young's modulus) is small hard film, ^{i.e., 1 × 10 -3 N / m} 2 or more at 1 × ¹⁰ 10 N /
It can be covered with a hard film of m ² or less.

[0025]

As is apparent from the above description, according to the present invention, the housing in the pressure-resistant container has a certain angle range with respect to the longitudinal direction of the housing, and has three angles around the longitudinal axis.
A pressure-resistant container inner housing having a 60 ° spherical inner peripheral surface, a seismometer main body that is housed in the pressure-resistant container inner housing, and has a center of gravity set just below the center position and provided on the seismometer main body, At least three or more ball bearings abutting at equal intervals on the spherical inner peripheral surface of the pressure-resistant container inner housing, and control means having a mode for driving the ball bearings for rotation, a mode for free, and a mode for clamping. And the ball bearing is covered with a film such as a hard rubber film having a coefficient of static friction in a dry state at room temperature of about 0.5 or more. In addition to being able to rotate freely to control the attitude passively by the action of gravity, it is also possible to actively control the attitude of the seismometer itself by rotating it. In addition, it is possible to fix the seismometer body in a pressure vessel housing with a ball bearing in the clamping state. In addition, since the ball bearing can be controlled to the rotational drive, the free state, and the clamped state by the control means, the attitude control can be performed by a simple mechanism.

[Brief description of the drawings]

1A and 1B are diagrams showing an embodiment of an attitude control device for earthquake observation according to the present invention, wherein FIG. 1A is a diagram showing the attitude control device for earthquake observation of FIG. 1B as a straight line connecting a center of gravity G and a center C; 1B is a cross-sectional view taken along the direction of arrow R in FIG. 1B, and FIG. 1B is a cross-sectional view taken along the vertical axis v of the pressure-resistant container in FIG. It is sectional drawing seen from the arrow S direction of B).

FIG. 2 is a flowchart for explaining a flow of a procedure of attitude control of the seismometer main body 2.

FIG. 3 shows a ball bearing 3 at an inclination angle of 45 °.
FIG. 6 is a vertical sectional view showing a state in which attitude control of the seismometer main body 2 to which three are mounted is completed.

FIG. 4 is a view showing another embodiment of the attitude control apparatus for earthquake observation according to the present invention, in which a cross section cut along a vertical axis v in FIG. 5A is indicated by an arrow U in FIG. It is sectional drawing seen from the direction.

5A shows an embodiment in which four ball bearings 3 are mounted, and is cut along a straight line connecting the center of gravity G and the center C of the attitude control device for earthquake observation shown in FIG. Sectional view of the cross section taken from the direction of arrow T in FIG. 4,
(B) is an external view of the seismometer main body 2 viewed from an oblique direction.

FIGS. 6A and 6B are cross-sectional views showing a state before and after the attitude control of the seismometer main body 2 when the pressure-resistant container 8 has been settled down in the direction of the long axis h. , FIG.
(C) and (D) show a state in which the pressure-resistant vessel 8 has landed on a plane inclined with respect to the direction of the long axis h, that is, the seismometer main body 2 viewed from the direction shown in FIG. Fig. 5
(A) is sectional drawing which shows the state before attitude | position control of the state rotated 90 degrees about the axis of the long axis h, and the state after attitude control.

FIG. 7 is a cross-sectional view of a conventional earthquake observation device.

FIG. 8 is a cross-sectional view schematically showing a conventional attitude control device of an earthquake observation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Housing in pressure-resistant container, 2 ... Seismometer main body, 3 ... Ball bearing, 4 ... Hard rubber film, 5 or 6 ... Micro motor or step motor, 7 ... Clamp pin, 8
... pressure vessel.

Claims (6)

[Claims] 1. A seismic observation attitude control device which is housed in a pressure-resistant container and whose attitude is controlled in accordance with the inclination of a landing surface, comprising: a cylindrical inner peripheral surface; An area within a certain angle range sandwiching a vertical axis perpendicular to the long axis of the pressure vessel at the center thereof, a pressure vessel inner housing formed into a spherical shape having a rotation center at an intersection of the long axis and the vertical axis. The spherical inner peripheral surface of the pressure vessel inner housing,
A seismometer main body, which is provided opposite to the intervening gap, and whose center of gravity is set just below the center position thereof, and which is provided on the seismometer main body and is provided on the spherical inner peripheral surface of the pressure-resistant container inner housing. At least three or more ball bearings abutting at equal intervals, and control means for setting a mode of rotating the ball bearing, a mode of setting a free state, and a mode of setting a clamp state, An attitude control apparatus for seismic observation, characterized in that the attitude control apparatus is covered with a film having a coefficient of static friction of about 0.5 or more in a dry state at room temperature. 2. The attitude control apparatus for earthquake observation according to claim 1, wherein said control means includes a motor. 3. The control means has an inclinometer, and drives the motor and rotates the ball bearing in the rotationally driving mode based on a detection signal of the inclinometer, thereby rotating the seismometer main body. The attitude control device for earthquake observation according to claim 2, wherein the attitude control is performed. 4. A hard film having an elastic modulus (Young's modulus) at room temperature of 1 × 10 ⁻³ N / m ² or more and 1 × 10 ¹⁰ N / m ² or less at room temperature. The attitude control device for earthquake observation according to claim 1. 5. The attitude control device for earthquake observation according to claim 1, wherein a clamp pin for clamping the seismometer main body is provided in the pressure-resistant container inner housing. 6. An attitude control device for seismic observation for controlling and fixing a horizontal attitude of a seismometer main body provided in a pressure-resistant container, wherein the static friction coefficient in a dry state at room temperature is substantially 0.5 or more. The ball bearing whose surface is covered with the membrane allows the main body of the seismometer to be supported on the pressure vessel, and the ball bearing is rotated by a motor in accordance with the inclination of the pressure vessel in the long axis direction and the rotation around the axis of the long axis. An attitude control device for seismic observation characterized by controlling and fixing the horizontal attitude of the seismometer main body.