RU2226675C2 - Fiber-optical device controlling vibration of load-carrying structure of underwater acoustic measurement aid in full-scale basin - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: fiber-optical device controlling vibration of load-carrying structure of underwater acoustic measurement aid in full-scale basin has inertial mass, springy backing and fiber-optical interferometer coming in the form of measurement and reference coils, source of coherent light and photodetector connected with output to recorder through amplifier. Measurement coil is wound interference fit on to outer surface of springy backing that presents hollow vessel made fast to controlled load-carrying structure. Inertial mass comes in the form of ball placed inside hollow vessel. EFFECT: provision for isotropic character of control over level of vibrations of object. 10 cl, 2 dwg

Description

The invention relates to the field of hydroacoustics and vibrometry and can be used to control the level of vibration of the supporting structures of the hoisting devices of various hydrophysical measuring instruments in a natural reservoir.

Installed in a natural body of water, for example at a buoy station, a sonar measuring instrument (RSI), in addition to its own weight, is exposed to wind, waves and currents that create hydrodynamic and mechanical stresses on its components, in particular on the cable cable. Under the influence of these factors, the supporting structures of the RCI are subjected to vibration in the natural reservoir, the level of which can take an unacceptably large value for the normal operation of the hydroacoustic working measuring instrument.

These circumstances lead to the necessity of introducing special vibrometers into the composition of underwater DSI to control the level of vibration of the supporting structures of the measuring instrument.

There are various fiber-optic devices suitable for solving the problem [1].

The closest in technical essence and the number of common features to the claimed is a fiber optic device [2], taken as a prototype.

The prototype contains an inertial mass in the form of a cylinder and two elastic substrates located on different sides of the inertial mass. There is also a fiber-optic interferometer with two coils wound tightly on the outer surface of the elastic substrates and optically matched with a coherent light source and a photodetector connected through an amplifier to the recorder.

The disadvantage of the prototype is the one-component nature of the vibration control of the object.

The technical result obtained from the implementation of the invention is to provide the isotropic nature of the control of the vibration level of the object, in particular the supporting structure of the hydroacoustic RSI.

This technical result is achieved due to the fact that in the known fiber-optic device for controlling vibrations of the supporting structures of hydroacoustic RSI in a natural reservoir containing an inertial mass, an elastic substrate and a fiber-optic interferometer made in the form of measuring and supporting fiber coils, optically matched with a coherent light source and a photodetector connected by an output through an amplifier to the recorder, the measuring coil being wound with an interference fit on the outer surface of another substrate, the elastic substrate is made in the form of a hollow tank, rigidly fixed to a controlled supporting structure, and the inertial mass is in the form of a ball placed inside the hollow tank.

The hollow tank is rigidly attached to the controlled structure, for example, using a clamping bracket.

The device also contains a neutral buoyancy float, on the outer surface of which a support fiber coil of the interferometer is wound, while the float is attached to the clamp bracket using a flexible cable cable.

The hollow tank and the float of neutral buoyancy perform the same shape and volume.

The support fiber spool can also be mounted on the outer surface of the clamping bracket.

The elastic substrate can be made in the form of a sphere or an ellipsoid of revolution.

The inertial mass can be suspended in the central part of the elastic substrate on weakly elastic suspensions, and the elastic substrate itself can be filled with liquid, for example, water or oil.

A coherent light source and a photodetector, as well as an amplifier with a recorder, are located on the underwater control center of the hydroacoustic RSI.

The invention is illustrated in the drawing, in Fig.1 which shows a diagram of the implementation of this technical solution for the carrier cable-cable RSI; figure 2 is an optical diagram of a fiber optic interferometer used in the device.

A fiber-optic device for controlling vibrations of a cable-cable 1 of a sonar RCI in a natural reservoir contains an inertial mass 2 made in the form of a ball, for example, of metal located inside an elastic substrate 3 made also of their metal, for example stainless steel, in the form of a ball ( 3 ₁ ) or an elliptical surface (3 ₃ ).

The device may also contain a float 4 neutral buoyancy, made in shape and dimensions that match the shape and size of the elastic substrate 3.

The elastic substrate 3 is rigidly attached to the controlled cable cable 1 using the clamping bracket 5 and a bolt. And the neutral buoyancy float 4 is attached to the bracket 5 using a flexible cable 7.

The inertial mass 2 ₂ can be attached to the inner surface of the elastic substrate 3 ₂ in its central part using slightly elastic suspensions 8. And the elastic substrate 3 itself can be filled with a liquid, for example, water or oil.

To pick up the signal about the vibrations of the cable in the x, y, z directions, the device includes a fiber optic interferometer, the measuring coil 9 of which is wound tightly on the outer surface of the elastic substrate 3, and the support coil 10 is wound on a neutral buoyancy float 4 or attached to the clamping bracket 5 (the last case is not shown in the drawing).

The coherent light source 11 and the photodetector 12 are optically matched with the measuring and supporting fiber coils 9, 10 (FIG. 2) of the interferometer.

The output of the photodetector 12 is connected through an amplifier to the recorder (not shown in the drawing).

The hydroacoustic RSI (not shown in the drawing) is lowered onto the cable cable 1, the vibrations of which should be controlled into a natural reservoir, for example, from an underwater control center (not shown in the drawing). Moreover, all the electronic components of the device, the photodetector 12 and the source of coherent light 11 are located outside the natural reservoir, for example, on the surface control center. The optical connection of the source 11 of coherent light and the photodetector 12 is carried out through the fibers of the optical cable 13 (figure 1).

The optical connection of the reference (10) and measuring (9) fiber coils is carried out via an optical fiber (not shown in the drawing) located in a flexible cable 7.

To control the vibration level of the RCI supporting structure in several places, a similar device is located in the required quantity in the corresponding places of the structure.

For example, figure 1 shows three variants of the device, secured with clamping brackets 5 and screws 6 in three places controlled cable cable, which in this case is the supporting structure of the RCI. The same elements of the device in figure 1 are digitized the same, but with different subscript numbers.

Fiber-optic device for controlling vibration of the supporting structure of the hydroacoustic RSI in a natural reservoir works as follows.

During mechanical vibrations of the cable cable 1, the elastic substrate 3 begins to move, and the inertial mass 2 begins to hit the inner surface of the elastic substrate 3. Moreover, this process proceeds regardless of the direction of mechanical action x, y, z.

In the event that it is necessary to highlight some preferred direction of vibration, for example, if the level of vibration in the z direction is much greater than the level of vibration in the x, y directions, then the elastic substrate 3 _{3 is} made in the form of an ellipsoid.

The impact of the inertial mass 3, made in the form of a ball, on the walls of the elastic substrate 3 leads to the appearance of acoustic pulses acting on the measuring fiber coil 9. These pulses are extracted at the output of the photodetector 12 and, after amplification, are recorded by the recorder.

The fiber-optic interferometer can operate in three modes.

In the counting mode of interference fringes, when the phase shift of the optical wave in the measuring fiber coil compared to the reference fiber coil is large enough. In this case, a pulse counter is used as a recorder.

In the homodyne mode, when the phase shift does not exceed π / 4. In this case, using a phase-shifting device (not shown in the drawing), the initial phase difference is set to π / 2, and an amplitude photocurrent detector is used as a recorder.

In the heterodyne mode, when a frequency modulator is introduced into one of the arms of the interferometer, a Doppler frequency meter is used as a detector.

The magnitude of the recorded signal is set by the length of the fibers in the measuring and supporting coils 9, 10, filling the elastic coil 3 with one or another viscous fluid and the stiffness used in option 2 of soft-elastic suspensions of inertial mass 2 ₂ .

Since the fiber lengths of the measuring and supporting coils are chosen the same and both coils are in the same hydrophysical conditions, for example wound on the same sphere, there will be no influence of extraneous factors on the meter readings (temperature, pressure, salinity, hydroacoustic interference).

Thus, using this fiber-optic device, the vibrations of the supporting structures of the hydroacoustic RSI in a natural reservoir are reliably controlled, regardless of the direction of vibration. That allows you to take appropriate measures in time to eliminate the emergency mode of RSI operation.

Sources of information

1. Balaev V.I. et al. Fiber-optic sensors of parameters of physical fields (review). Quantum Electronics. - 1984, No. 1, pp. 10-30.

2. Patent 2115933 of the Russian Federation, cl. G 01 P 15/08, 1998 - prototype.

Claims (11)

1. Fiber-optic device for controlling vibration of the supporting structure of a hydroacoustic working measuring instrument in a natural reservoir, containing an inertial mass, an elastic substrate and a fiber-optic interferometer made in the form of measuring and supporting fiber coils with the same fiber lengths, optically matched with a coherent light source and a photodetector connected by the output through the amplifier to the recorder, and the measuring coil is wound with an interference fit on the outer surface of the elastic base ki, characterized in that the elastic substrate is a hollow container rigidly fixed to a supporting structure controlled, and inertia mass - in the form of a ball, located inside the hollow container. 2. The fiber optic device according to claim 1, characterized in that it further comprises a neutral buoyancy float, on the outer surface of which a reference fiber coil of the interferometer is wound. 3. The fiber optic device according to claim 2, characterized in that the hollow container is rigidly attached to a controlled supporting structure using a clamping bracket. 4. The fiber optic device according to claim 1, characterized in that the elastic substrate is made in the form of a sphere. 5. The fiber optic device according to claim 1, characterized in that the elastic substrate is made in the form of an ellipsoid. 6. The fiber optic device according to claim 1, or 4, or 5, characterized in that the inertial mass is suspended in the center of the elastic substrate on weakly elastic suspensions. 7. The fiber optic device according to claim 1, or 4, or 5, characterized in that the elastic substrate is filled with liquid. 8. The fiber optic device according to claim 1, characterized in that the coherent light source and the photodetector, as well as the amplifier with the recorder, are located on the surface control center of the sonar measuring instrument. 9. The fiber optic device according to claim 3, characterized in that the neutral buoyancy float is attached to the clamp bracket using a flexible cable. 10. The fiber optic device according to claim 3, characterized in that the support fiber coil is fixed to the outer surface of the clamping bracket. 11. The fiber optic device according to claim 9, characterized in that the hollow tank and the float of neutral buoyancy are made of the same shape and volume.

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