JPH09277984A - Antimotion device for ocean structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antimotion device for an ocean structure which can be applied to change of a period of rocking of the ocean structure such as a vessel, in which power consumption is less, and in which a burden of mainte nance work is reduced. SOLUTION: A coil track 3 is disposed along an upper surface of a guide 1 fixed on a vessel 2, a movable mass 4 is disposed to cover the coil track 3 to passively reciprocate on the guide 1 at a shorter period than a period of supposed rocking of the vessel 2, and permanent magnets 5 are disposed inside the movable mass 4 to face each other on both sides of the coil track 3 to form magnetic flux almost in the perpendicular direction to the reciprocating direction. A regenerative current adjusting means to adjust energization quantity of an induced current generated at the coil track 3 by reciprocation of the movable mass 4 is controlled by a control device to set the reciprocation at a phase delay of about 90 deg. corresponding to the period of rocking of the vessel 2 to provide a proper regenerative braking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reducing vibration of marine structures used for suppressing the rocking of marine structures such as ships, barges and other floating bodies.

[0002]

2. Description of the Related Art As a conventional anti-sway device for a ship,
As shown in FIG. 5, it is known that the movable mass c reciprocates along an arcuate guide b fixed to an appropriate position of the ship a, which is the same as the assumed swing of the ship a. The design is such that the phase is delayed by about 90 ° in a cycle, and the passive system in which the movable mass c is passively resonated with the swing of the ship a is used, or a motor (not shown) is installed in the movable mass c. As a hybrid system in which reciprocating motion is performed while active control is applied, the swing of the ship a is suppressed.

[0003]

However, in the case of the passive system in which the movable mass c is made to resonate passively, the natural period is determined once it is designed. If the cycle changes depending on the loading state of cargo and the wave height of the ocean, there is a problem that the damping effect is reduced.

On the other hand, in the case of the hybrid system in which the movable mass c is actively controlled to reciprocate, it is possible to cope with a change in the swing cycle of the ship a, but the rush into the motor. There is a problem that the power consumption increases due to the large current.

Further, as shown by the chain double-dashed line in the figure, it is necessary to draw the power cable d into the movable mass c in order to supply the power, but generally, this kind of power cable d draws a curve. It is held by the outer skin so as to be drawn into the movable mass c, and follows the movement of the movable mass c while changing the bending position, so that the deterioration of the power cable d progresses quickly and the life is short. There was also a defect.

Further, mechanically reciprocating the movable mass c with a motor complicates the structure, which easily causes a failure and increases the burden of maintenance work.

The present invention has been made in view of the above situation, and can cope with changes in the swing cycle of a marine structure such as a ship, consumes less power, and can perform maintenance work. It is an object of the present invention to provide an anti-sway device for offshore structures that is less burdensome.

[0008]

DISCLOSURE OF THE INVENTION The present invention is directed to a guide fixed to a marine structure which is formed in an arc shape with both sides bent upward, and a coil arranged in an arc shape along the upper surface of the guide. An orbit and a direction that is arranged across the coil orbit so that it can passively reciprocate on the guide in a cycle shorter than the expected rocking cycle of the offshore structure, and in a direction substantially perpendicular to the reciprocating direction. A movable mass in which permanent magnets are arranged to face each other across the coil orbit so as to form a magnetic flux, a swing detecting means for detecting swing of an offshore structure, and a position detecting for detecting a moving position of the movable mass with respect to a guide. Means and
Based on the regenerative current adjusting means for adjusting the energization amount of the induced current generated in the coil orbit by the reciprocating movement of the movable mass, the swing signal from the swing detecting means and the position signal from the position detecting means. Control for controlling the regenerative current adjusting means so that the reciprocating motion of the movable mass corresponds to the period of rocking of the marine structure and has a phase delay of about 90 ° so as to apply appropriate regenerative braking to the movable mass. The present invention relates to an apparatus for reducing vibration of a marine structure, which is provided with a device.

Further, the regenerative current adjusting means may be composed of an input resistor and a transistor connected in series to the coil orbit via a rectifier.

When the offshore structure is rocking, the movable mass passively reciprocates on the guide in a cycle shorter than the rocking cycle of the offshore structure. The regenerative current adjusting means is controlled by the control device on the basis of the rocking signal from the motion detecting means and the position signal from the position detecting means, and the reciprocating motion of the movable mass corresponds to the rocking cycle of the marine structure and is about The energization amount of the induced current generated in the coil orbit is adjusted so that the phase delay is 90 °.

That is, when the movable mass reciprocates on the guide while the magnetic flux is formed by the permanent magnets in a direction substantially perpendicular to the reciprocating direction of the movable mass, an induced current is generated in the coil orbit. At this time, if the amount of induction current is adjusted to control the current, the maximum regenerative braking when the induction current is applied without being restricted can be moved by arbitrarily reducing the amount of induction current. Since it is possible to act on the mass, reciprocating motion of the movable mass is suppressed by applying regenerative braking to the movable mass that reciprocates on the guide in an appropriate size. It is possible to respond to changes in the motion cycle.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an example of an embodiment for carrying out the present invention. As shown in FIG. 1, a ship 1 is a marine structure in which guides 1 formed in an arc shape with both sides bent upward are formed. It is fixed at an appropriate position such as the engine room of No.2.

On the upper surface of the guide 1, a coil track 3 formed in a concentric arc shape along the upper surface is arranged with the guide 1, and further, at a cycle shorter than an expected rocking cycle of the ship 2. A movable mass 4 is disposed across the coil track 3 so as to be able to passively reciprocate on the guide 1. As shown in FIG. The permanent magnets 5 having magnetic poles opposite to each other so as to form a magnetic flux in a direction (width direction of the movable mass 4) substantially perpendicular to the direction indicated by the arrow A therein are arranged so as to face each other with the coil track 3 interposed therebetween. Has been done.

Further, a magnetic scale 6 is laid along the upper surface of the guide 1, and a position detecting head 7 capable of detecting a relative position with respect to the magnetic scale 6 is attached to the lower surface of the movable mass 4. The magnetic scale 6 and the position detecting head 7 constitute a position detecting means 8 for detecting the moving position of the movable mass 4 with respect to the guide 1.

Further, as shown in FIG. 3, the coil orbit 3
Constitutes a closed loop capable of circulating the induced current generated in the coil orbit 3 due to the reciprocating movement of the movable mass 4, and the energizing amount of the induced current can be adjusted by the regenerative current adjusting means 9. is there.

The regenerative current adjusting means 9 has a coil orbit 3
On the other hand, for example, an input resistor 11 and a transistor 12 are connected in series via a bridge-type rectifier 10, and the transistor 12 is controlled by a control signal 14 from a control device 13 so that the induction current flows. The amount is adjusted.

The control device 13 has an angular velocity signal 16 (swing signal) from an angular velocity meter 15 (swing detection means) and a position signal 17 from a position detection head 7 which constitutes the position detection means 8. The reciprocating motion of the movable mass 4 is based on the angular velocity signal 16 and the position signal 17, and the reciprocating motion of the movable mass 4 corresponds to the swing cycle of the ship 2 and has a phase delay of about 90 °. Thus, the transistor 12 of the regenerative current adjusting means 9 is controlled so that the movable mass 4 is appropriately regeneratively braked.

In this embodiment, the marine structure to be reduced is shown as the marine structure 2. Therefore, the existing angular velocity meter 15 provided in the marine vessel 2 is used as the rocking detecting means. Although it is used, it goes without saying that the swing detecting means may be separately provided.

When the ship 2 is swinging, the movable mass 4 is guided by the guide 1 in a cycle shorter than the swinging cycle of the ship 2.
It reciprocates passively above, but at this time, the angular velocity meter 15
The controller 12 controls the transistor 12 of the regenerative current adjusting means 9 on the basis of the angular velocity signal 16 from the position detecting head 7 and the position signal 17 from the position detecting head 7 which constitutes the position detecting means 8 so that the reciprocating motion of the movable mass 4 is controlled by the ship. The energization amount of the induced current generated in the coil track 3 is adjusted so as to correspond to the oscillation cycle of 2 and have a phase delay of about 90 °.

That is, when the movable mass 4 reciprocates on the guide 1 while the magnetic flux is formed by the permanent magnet 5 in a direction substantially perpendicular to the reciprocating direction of the movable mass 4, the movable mass 4 is guided to the coil orbit 3. A current will be generated.At this time, if the current amount is controlled by adjusting the energization amount of the induced current, the maximum regenerative braking when the induced current is applied without being restricted Since the movable mass 4 can be arbitrarily reduced and acted on the movable mass 4, the reciprocating motion of the movable mass 4 is performed by applying regenerative braking to the movable mass 4 that reciprocates on the guide 1 with an appropriate size. Thus, it is possible to suppress the fluctuation and respond to the change in the swing cycle of the ship 2.

Therefore, according to the above embodiment, the reciprocating motion of the movable mass 4 corresponds to the rocking cycle of the ship 2 even if the rocking cycle of the ship 2 changes depending on the loaded state of the cargo or the wave height of the ocean. In addition, since the phase can be controlled to have a phase delay of about 90 °, the maximum damping effect can always be obtained.

Further, the reciprocating motion of the movable mass 4 is basically passively performed by the swing of the ship 2, and this is suppressed by the regenerative braking so as to correspond to the change of the swing cycle of the ship 2. Since it requires only a small amount of electric power for the reciprocating movement of the movable mass 4, and does not require a large inrush current as in the case of using a motor,
The power consumption can be significantly reduced.

Further, since it is not necessary to mechanically reciprocate the movable mass 4 by a motor or the like, and it is not necessary to pull the power cable into the movable mass 4 for supplying electric power.
An extremely simple structure with few failures can be made, continuous use is possible for a long period of time, and the burden of maintenance work can be significantly reduced.

FIG. 4 shows another embodiment of the present invention.
Two coil tracks 3 are provided, and three permanent magnets 5 are arranged inside the movable mass 4 so as to face each other with both coil tracks 3 sandwiched between them. In addition, it is possible to provide the coil orbit 3 of three or more in the same manner.

The device for reducing vibration of a marine structure according to the present invention is not limited to the above-mentioned embodiment, and the marine structure may be other than a ship, and the vibration detecting means,
It goes without saying that the position detecting means and the regenerative current adjusting means are not limited to the illustrated example, and that various modifications can be made without departing from the scope of the present invention.

[0027]

EFFECTS OF THE INVENTION According to the above-described apparatus for reducing vibration of a marine structure of the present invention, various excellent effects as described below can be obtained.

(I) Even if the period of rocking of the marine structure changes depending on the loading condition of the cargo, the wave height of the ocean, etc., the reciprocating motion of the movable mass corresponds to the period of rocking of the marine structure and is about 90. Since the phase delay can be controlled so that the phase is delayed, the maximum damping effect can always be obtained.

(II) Basically, the reciprocating motion of the movable mass is passively performed by the rocking of the marine structure, and it is suppressed by regenerative braking so as to correspond to the change of the rocking cycle of the marine structure. Since it requires only a small amount of electric power for the reciprocating movement of the movable mass, and does not require a large inrush current as in the case of using a motor or the like, the power consumption can be remarkably reduced. it can.

(III) Since it is not necessary to mechanically reciprocate the movable mass by a motor or the like, and it is not necessary to pull the power cable into the movable mass to supply electric power,
An extremely simple structure with few failures can be made, continuous use is possible for a long period of time, and the burden of maintenance work can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment for implementing the present invention.

FIG. 2 is a cross-sectional view of the movable mass and the coil track of FIG.

FIG. 3 is a conceptual diagram showing a control system in an example of an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing another example of the embodiment for carrying out the present invention.

FIG. 5 is a schematic view showing a conventional example.

[Explanation of symbols]

 1 Guide 2 Ship (Offshore Structure) 3 Coil Trajectory 4 Movable Mass 5 Permanent Magnet 8 Position Detection Means 9 Regenerative Current Adjusting Means 13 Control Device 15 Angular Velocity Meter (Vibration Detection Means) 16 Angular Velocity Signal (Oscillation Signal) 17 Position Signal

Claims (2)

[Claims] 1. A guide which is fixed to a marine structure and is formed in an arc shape in which both sides are bent upward, and a coil trajectory which is arranged in an arc shape along the upper surface of the guide, and an assumed marine structure. The coil is arranged so as to straddle the coil so as to passively reciprocate on the guide in a cycle shorter than the swing cycle of an object, and to form a magnetic flux in a direction substantially perpendicular to the reciprocating direction. A movable mass in which permanent magnets are arranged opposite to each other across a track, swing detection means for detecting the swing of the marine structure, position detection means for detecting the moving position of the movable mass with respect to the guide, and the movable mass reciprocates. Regenerative current adjusting means for adjusting the amount of the induced current generated in the coil orbit by moving, and the movable mass based on the swing signal from the swing detecting means and the position signal from the position detecting means. A control device for controlling the regenerative current adjusting means so that the reciprocating motion of 1 corresponds to the period of rocking of the offshore structure and has a phase delay of about 90 ° so as to apply appropriate regenerative braking to the movable mass. An anti-swing device for offshore structures. 2. The vibration control device for a marine structure according to claim 1, wherein the regenerative current adjusting means comprises an input resistance and a transistor connected in series to the coil orbit through a rectifier.