RU125363U1 - ACTIVE TWO-GRADE VIBRATION PROTECTION DEVICE - Google Patents

Abstract

The invention relates to the field of instrumentation, mechanics of systems with auto-regulation, and more specifically, to the design of active vibration-proof devices. The proposed active two-stage vibroprotection device contains a mechanical part having a base plate with four elastic supports supporting the base plate, on which eight accelerometers and eight service magnetoelectric propellers are mounted. Elastic supports are installed on the base plate supporting an additional base plate, on which eight accelerometers and eight service magnetoelectric propellers are installed, two electronic six-channel autoregulators connected in such a way that both base plates are included in series partial active vibration dampers suppressing six modes of carrier plates , so that the module of the transfer function of a two-stage device is the product of the modules of the functions of transfer of partial a ktivnyh vibroprotective devices. Ill.5

Description

The invention relates to the field of instrumentation, mechanics of systems with auto-regulation, and more specifically, to the design of active vibration-proof devices.

Many modern measuring devices and technological equipment need effective protection against vibrations. These include: 1) high-resolution X-ray diffractometry (flat-wave topography, small-angle scattering in film technologies, standing wave method, etc.); 2) microprobe apparatus, microscopes, nano-manipulators for research and technologies in the field of micro- and nanoelectronics, nano-mechanics; 3) laser experimental and technological devices; 4) apparatus for growing biological and inorganic crystals (this list can be continued). Equally great is the need for active protection from the vibrations of sensitive equipment on spacecraft, airplanes, and other vehicles.

Expensive massive foundations in basements are not always able to isolate equipment from vibrations that are excited by trucks, buses, trolley buses, trains. In such cases, active vibration protection panels are the only means of protection against vibrations. They significantly reduce the requirements for noise at the location of sensitive equipment.

The active vibroprotection device is known, consisting of a mechanical part containing a base plate with four elastic supports supporting a carrier plate, on which eight accelerometers and eight service magnetoelectric propellers are installed (RF Patent No. 2337390 "Active vibration-proof panel (box) with compensation of the accelerometer tilt signal for stationary conditions and vehicles ", IPC G05D 19/00, priority from 09.10.2006) This patent is selected as a prototype of the proposed device.

The main disadvantage of the prototype is that, despite the expansion of the border of the active range towards low frequencies (from ≈2 Hz to ≈0.2 Hz) and an increase in the maximum oscillation suppression factor (from ≈40 dB to ≈60 dB), which are achieved in this design, there are a number of specific applications for which the achieved parameters are insufficient due to the inability of using separate active vibration-proof devices to obtain the necessary characteristics.

The technical task of the present utility model is the creation of an active vibroprotection device providing an increase in the range of adjustable parameters, which will protect devices especially sensitive to vibrations (permissible vibration level ≤ ^10-6 g), which, if necessary, are installed on supports with high vibration level (≥10 ^{- 3} g) and also guarantee the protection of vibration-sensitive devices on vehicles.

It should be noted that the range of experimental and technological equipment that is particularly sensitive to vibration is wide enough; for example, it includes: 1) high-resolution X-ray diffractometry (flat-wave topography, small-angle scattering in film technologies, the standing wave method, etc.), 2) microprobe apparatus, microscopes, nano-manipulators for research and nanomechanics and micro- and nanoelectronics, 3) laser experimental and technological devices, 4) apparatus for growing biological and inorganic Sgiach crystals

On the ground, the most unfavorable for the placement of sensitive equipment are buildings located close to highways or containing their own sources of noise. On vehicles (aircraft, helicopter, car), vibrations are essential in the frequency range from (2-4) Hz to (50-100) Hz, therefore, for effective protection of sensitive devices, such as precise gravimeters, vibration-proof devices with a slope are needed characteristics of at least 50 dB / dec, which is not achievable when using known designs.

The technical result is the expansion of the scope of the active vibroprotection device and increase the reliability of sensitive instrumentation.

The stated technical problem and the result are achieved as a result of the fact that in an active vibroprotection device containing a mechanical part having a base plate with four elastic supports supporting a carrier plate on which eight accelerometers and eight service magnetoelectric propulders are installed, the elastic supports are mounted on the carrier plate, supporting additional carrier plate, on which eight accelerometers and eight service magnetoelectric propellers are installed, two electronic six channel autoregulators. The mentioned autoregulators are connected in such a way that both carrier plates are included in series partial active vibration-proof devices that suppress six modes of oscillations of the carrier plates, so that the transfer function module of a two-stage device is a product of the transfer function modules of the partial active vibration protection devices.

The essence of the utility model is illustrated by diagrams and graphs presented in the figures.

Figure 1 - Single-mode design of a two-stage active vibroprotection device;

Figure 2 - Frequency dependence of the module loop transfer function of a partial vibration-proof device;

Figure 3 - Frequency response coefficient of the partial vibration protection device;

4 — Frequency dependence of the total transmission coefficient of a two-stage vibration-proof device;

FIG. 5 — Frequency dependence of the total transmission coefficient of a two-stage vibration-proofing device adapted for an aircraft-based microgravimeter.

The proposed design of a two-stage active vibroprotective device greatly expands the scope of the equipment in question.

The single-mode design of a two-stage active vibroprotection device is shown schematically in FIG. Here 1 is a base plate, 2 is a protected object, 3 is an elastic support, 4 is a carrier plate, 5 is an accelerometer, 6 is a service magnetoelectric propulsion device, 7 is an auto-regulation / control electrical circuit, 8 is an elastic support, 9 is an additional base plate, 10 is an accelerometer, 11 is a service magnetoelectric propulsion unit, and 12 is an auto-regulation / control electrical circuit. From the scheme it follows that the mechanical part of the device contains two nodes, which are partial active vibration-proof devices connected in series, with the base plate 4 of the lower node being the base plate of the top node, in which the additional base plate 9 is applied.

Active two-stage vibroprotection device operates as follows. The support plate 1 is rigidly installed on the working surface (table, foundation, vehicle body) with an unacceptably high vibration level for the protected equipment, so the task of the device is to isolate the protected object 2 from the vibrations of the support plate 1. On the support plate 1 there are installed elastic supports 3, supporting carrier plate 4, to which the accelerometer 5 and the movable stop of the magnetoelectric propulsion unit 6 are attached. Together with the electrical circuits 7, these nodes form a closed control circuit containing an elastic oscillation A controller (carrier plate 4 mounted on elastic supports 3), an accelerometer 5, electronic circuits 7 and a service magnetoelectric propeller 6. In this mechanoelectric circuit, oscillations of the carrier plate 4 are suppressed, and the active frequency range and maximum oscillation suppression ratio (or transmission coefficient) are determined parameters of electrical control circuits 7.

Consistently with the first cascade of the active vibroprotection device discussed above, a second cascade is installed, supported on the carrier plate 4. Elastic supports 8 are mounted on the carrier plate 4 supporting the carrier plate 9 to which the accelerometer 10 and the movable stop of the magnetoelectric propulsion device 11 are attached. These nodes form a closed control circuit containing an elastic oscillator (carrier plate 9 mounted on elastic supports 8), an accelerometer 10, electronic circuits 12 and a service magnetoelectric All propulsion 11. In this mechano-electric circuit, the oscillations of the carrier plate 9 are suppressed, and the active frequency range and maximum oscillation suppression factor (or transmission coefficient) are determined by the parameters of the electric control circuits 12.

When two partial active vibroprotective devices are connected in series, the total transmission coefficient is equal to the product of the transmission coefficients of the partial vibration protection devices.

In the actual design, eight accelerometers and eight service drivers are installed on each base plate (4 and 9). All modes of oscillation of carrier plates are measured and with the help of six control circuits (for each partial device) all six modes of oscillation of carrier plates, three torsion and three translational, are suppressed. The total height of the two-stage device will be ≈120 mm.

The stability and dynamic characteristics of each partial auto regulator are determined by the correctly calculated loop transfer function H (iω) = M (iω) · K (iω), where M (iω) is the transfer function of electrical circuits, and K (iω) is the complete transfer function of the mechanical system . The latter can be represented as the product K (iω) = К _A (iω) · K _M (iω) · K _D (iω), where K _A (iω), K _M (iω), K _D (iω) are the transfer functions , respectively, accelerometer, mechanical oscillator / suspension, magnetoelectric propulsion. Usually, the designs of accelerometers and magnetoelectric propellants are chosen so that in the active frequency range they do not introduce a significant phase shift in K (iω), in which case K (iω) = K _A · K _M (iω) · K _D , where K _A and K _{D are} the transmission coefficients of accelerometers and thrusters, respectively.

The loopback transfer function, calculated taking into account the conditions noted above, may have the following form:

Here, the first factor reflects the quadratic frequency dependence of the accelerometer signal, the second represents the transfer function of the integrator, the third the corrector, and the fourth the mechanical oscillator.

The frequency dependence of the module of the loop transfer function is schematically shown in FIG. 2. It can be seen that at frequencies below the resonance frequency of the mechanical oscillator 1 / 2πT ₀ ≈10 Hz, the dependence under consideration is described by a straight line with a slope of ≈30 dB / dec, and above the resonance frequency, a straight line with an inclination of ≈-20 dB / dec. With such a frequency dependence of the modulus of the loop transfer function | H (iω) | It is obvious that the maximum value of | H (iω) |, which is reached at the point of resonance, depends on the lower limit of the active frequency range. From Figure 2 it is seen that at the lower limit of the active frequency range of ≈0.2 Hz, a maximum of | H (iω) | ≈60 dB is reached (solid curve), and at the lower limit of ≈2 Hz, only <40 dB (dashed curve ).

The frequency dependence of the module of the loop transfer function | H (iω) | shown in FIG. 2 gives a satisfactory frequency response of the oscillation suppression factor K (ω) shown in FIG. 3 in the case when the vibration protection device is intended to isolate the protected object from the external environment, that is, from the vibration of the base plate a (t). In this case, at frequencies higher than the resonance of the elastic oscillator, the total oscillation suppression factor is the product of the suppression factors of the active circuit and the passive element (carrier plate mounted on elastic supports). Since the frequency dependences of these two factors are straight lines with a slope of the opposite sign, -20 dB / dec and +20 dB / dec, the full dependence K (ω) above the resonance frequency has the form of a plateau, as shown in Figure 3. Here, also, as in Figure 2, the solid curve corresponds to the lower limit of the active frequency range of ≈0.2 Hz, and the dotted, ≈2 Hz.

The effectiveness of the partial active vibroprotection device shown in Figure 3 for the level of technology used is the limit. Therefore, for a number of applications that require a higher suppression ratio and a greater steepness of the curve in the region below the frequency of mechanical resonance, a two-stage active vibroprotection device can be optimal, greatly increasing the efficiency of conventional active vibroprotection devices. The two-stage activation of partial active vibration-proof devices is a mechanical analogue of the electrical circuit of two high-pass filters connected in series.

Figure 4 shows the frequency dependence of the total transfer coefficient K (ω) of a two-stage device, which is equal to the product of the transfer coefficients of the two partial devices. The solid curve in the graph corresponds to the lower boundary of the active range ≈2 Hz, and the dotted, ≈0.2 Hz. It can be seen that the slope of the transmission curves in the frequency range below the resonance of the mechanical oscillator reaches ≈ –60 dB / dec, and the maximum oscillation suppression factor is ≈60 dB and ≈120 dB, respectively.

Two-stage active vibroprotective devices with the characteristics shown in Figure 4 can be successfully used where the effectiveness of conventional devices is insufficient.

Firstly, it is the protection of a particularly sensitive to vibrations measuring or technological equipment, which is located on supports with a high level of vibrations. It is important that the two-stage design easily adapts to the specified support vibration levels and the residual vibration level of the carrier plate by optimizing such parameters of partial vibration protection devices as the loop transfer function H (iω), the power of the service drivers, the sensitivity of the vibration measurement circuits. The slope of the oscillation suppression curve to ≈60 dB / dek can be achieved, and the maximum oscillation suppression coefficient (residual vibration level of the carrier plate) will be limited only by thermal noises of the mechanical design [Aki K., Richards P. Quantitative seismology, M .: Mir, 1983 ] and vibration measurement circuits.

Secondly, it is the protection of vibration-sensitive equipment on vehicles. Examples include autonomous navigation systems, as well as precision gravimeters used for geological surveys from an aircraft or helicopter.

A specific example is a two-stage active vibroprotection device adapted to the protection conditions of highly sensitive gravimeters GT-1A / 2A on board aircraft (helicopters). World-class gravimeters GT-1A / 2A (manufactured by NTP Gravtekhnologiya CJSC) are widely used for airbrush and geological exploration by Russian and leading foreign companies. However, the maximum sensitivity of the measuring cell of gravimeters is not fully implemented due to vibrations on board aircraft (helicopters). So the parking sensitivity ≈0.1 mGal in flight deteriorates to ≈0.6 mGal due to the lack of effectiveness of the used passive protection against side vibrations. It is estimated that the use of active vibroprotective devices instead of passive ones may decrease the influence of onboard vibrations on their sensitivity (or SCR, the error in measuring gravity) by a factor of ten. Established, agreed with the manufacturer of gravimeters, the basic requirements for active vibration protection devices: 1) the limiting frequency of the active range ≈1 Hz in six modes of oscillation and 2) oscillation suppression curve with a slope of at least 40 dB / dec, 3) the design of the active system should not go for the dimensions of the passive damper.

From Figure 5 it is seen that the two-stage design of the vibration-proof device meets the specified requirements. The dotted line on the graph indicates the frequency dependence of the passive protection transmission coefficient, which is a straight line with a slope of -20 dB / dek. The two-stage active protection provides, as you can see, the limiting frequency ≈1 Hz, the slope of the oscillation suppression curve of ≈-60 dB / dec, and the maximum suppression coefficient of ≈60 dB at frequencies above the resonance of the mechanical suspension. If we consider that the maximum vibrations on board the aircraft are located in the frequency range from Hz to ≈100 Hz, it is clear that the effectiveness of the two-stage device in this case is very high. (If necessary, it can be enhanced.).

The above indicates the industrial applicability of the utility model.

Claims (1)

Active two-stage vibroprotection device containing a mechanical part having a base plate with four elastic supports supporting a carrier plate, on which eight accelerometers and eight service magnetoelectric propellers are installed, characterized in that elastic supports supporting an additional plate, supporting an additional plate, on which eight accelerometers and eight service magnetoelectric propellers, two electronic six-channel auto-regulators, connected in such a way, are installed then the two bearing plates are connected in series partial Active Vibration device suppressing vibration modes six bearing plate so that the transfer function module is a two-stage device is the product of the transfer functions of the partial modules active vibration isolation devices.

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