RU1812429C - Method for measurement of frequency and amplitude of sea waves caused by wind - Google Patents

Abstract

Application: the invention relates to measuring technique and allows to increase the accuracy of recording the profile of waves on the water surface during meteorological and oceanographic studies. SUMMARY OF THE INVENTION: harmonic signals of a certain frequency and amplitude are formed on the coils of the remote deflection of the accelerometers, which are superimposed on the informative signals of the sensors. The formation of the output signal by the measured parameter includes the extraction and compensation of signals from the accelerometer informative signal by the angle of inclination of these sensors relative to the vertical and component from the acceleration of free fall. 4 ill.

Description

ate

WITH

The invention relates to measuring technique, in particular for measuring wind wave parameters and can be used, for example, in meteorological and oceanographic studies. .. ;. The aim of the invention is to improve the accuracy of measurement.

In FIG. 1 shows a structural diagram of the processing of informative signals, where 1 is the float of the sensor for vertical oscillations of the water surface level, 2 is the alternator, 3 are accelerometers (BWW - remote deflection coil, DS is the signal sensor), 4.10 are difference amplifiers: 5, 11 - double integrators, 6 - functional converter, 7 - adder, 8 - dividing device. 9 - source of support For example, 12 - the registrar.

The float 1 of the sensor of vertical fluctuations of the water surface level is rigidly connected to accelerometers 3. The output of the alternator 2 is connected to the input of the distance coils of the accelerometers 3. The outputs of the accelerometers 3 are connected to the inputs of the first difference amplifier 4 and adder 7. The output of the first difference amplifier 4 through the first double integrator 5 and functional converter b, and the output of the adder 7 is directly connected to the sharing device 8. The output of the sharing device 8, a

from th

Nь N) О

also, the output of the reference voltage source 9 is connected through a second differential amplifier 10 and a second double integrator 11 to a waveform profile recorder 12.

A waveograph that implements this measurement method may be performed according to autosample 1613861. The waveograph contains three P & spaced at the same distance from each other base floats, rigidly interconnected by a boom structure, and a buried cargo associated with the floats. A weather vane is attached to one of the floats to orient the entire device in the direction of wave propagation. The sensor of vertical fluctuations of the water surface level is made in the form of a float, which, due to the axial hinge, has a vertical degree of freedom relative to the structure along the axis passing through its center. Two vertically oriented accelerometers are spaced apart from the sensor float of vertical vibrations of the water surface level, spaced apart from the sensor float by the same distance in the direction of the vane axis,

The device operates as follows. In case of wind waves, due to the weather vane, the entire measuring system is oriented parallel to the direction of wave propagation, and due to the basic floats associated with the buried load, the stability and stability of the structure are ensured and its horizontal displacements are reduced. The float T, due to the structural design, has free movement in the vertical and minimal movement in the horizontal planes. Two vertically oriented accelerometers 3 are rigidly connected to the float 1, and a harmonic signal is supplied to the input of the remote deflection coils from the alternator 2. The frequency of the harmonic signal f is selected in the range fp f fc, where fo is the frequency of the upper boundary of the measured wavelength range, fc is the natural frequency of the accelerometer, and its amplitude is A - D Q / k, where AQ is the response threshold of the accelerometer, k is the slope of the characteristic remote deflection coils.

By means of a harmonic signal, the sensitive element of the accelerometers is oscillated at a high frequency. As a result, the friction of the silent inertial mass of the accelerometers becomes equal to zero, which ensures a decrease in the response threshold of the accelerometers and, therefore, increases the measurement accuracy in the low-frequency range,

Accelerometers 3 give out signals including the following components: First accelerometer

1) component of vertical acceleration a in aycos v (for example, with a positive sign, Fig. 2);

2) a g gcos v component of the acceleration of gravity (for example, with a negative sign, Fig. 2); 3) component of angular acceleration. where Li is the distance from the center of mass of the object db of the first accelerometer (for example, with a positive sign, Fig. 2);

4) a harmonic signal from an ac generator Aaslnw t. The second accelerometer 1) is a component of vertical acceleration a in aycos v (with a positive sign, respectively, Fig. 2); 2) component of the acceleration of gravity a g gcos v (respectively, with a negative sign, Fig. 2);

3) the component from the angular acceleration Ј v La, where La is the distance from the center of mass to the second accelerometer (in accordance with Fig. 2 with a negative sign);

4) a harmonic signal from an Aasinwt ac generator.

Thus, the signals of the first and second

Accelerometers can be described respectively by the following expressions:

a aycos v-gcosv + v Li + D 3 $ a aycos v -gcos v - V La + D asin t.

If the accelerometers are identical and the distance from the center of mass to the accelerometers 3 is equal to Lt La L, then the total signal from the two accelerometers generated by the adder 7 (with a transmission coefficient of 1/2). can be described by the expression

a + a (ay-g) cos v + A asin rw t.

The differential signal from the accelerometers generated by the differential amplifier 4 having a gain of 1/2, in this case, is written as

a -a Lv.

moreover, the coefficient L determines the sensitivity of the device according to angular acceleration.,.

In order to obtain information on angle v, the signal from the differential amplifier 4 needs to be integrated twice. Thus, the output signal of the integrator 5

is proportional to the angle v, which the functional converter b converts in accordance with the cosine function cosv. The division of the signal from the adder 7 into the signal from the functional Converter b occurs in the divider 8, the output signal of which can be written as

Us ay - g 4- Yes sin cos v

The signal from the divider 8, which is proportional to the difference between the vertical acceleration of the waveograph and the acceleration of free fall, is fed to one of the inputs of the difference amplifier 10, to the second input of which a signal from the reference voltage source 9 is proportional to the value of the acceleration of free fall. In this way, it will be compensated for by the distance from the acceleration of gravity. The signal from the difference amplifier will be proportional to the following value

U13, ay 4- Yes

cosv

The signal from the differential amplifier S proportional to the vertical acceleration of the float of the vertical vibration sensor of the water surface level 1 is integrated twice by the double integrator-11. The double integrator 1 f filters the signal for frequencies lying above the measured frequency range of the waves, therefore, the component of the signal Ui3

U yes

stn with I cosV

where the frequency a is determined by the alternator 2 will not introduce a fault in the measurements of waveforms recorded by the recorder 12.

As accelerometers, sensors of the DLUMM type (microminiature linear acceleration sensor) can be used. Difference amplifiers, adder and integrators can be made on the basis of operational amplifiers of the 140UD14 series.

The functional converter and the dividing device can be performed, for example, on the basis of the analog-to-digital converter 572PV T, read-only memory device 568RE1 and digital-to-analog converter 572PA2. A loop oscilloscope, a magnetic storage device, etc. can be used as a recorder.

The inventive method for measuring the parameters of sea waves can be implemented in the device for the application for invention No. 4497433 of 10.24.88, with 5 positive decision on the issuance of the copyright certificate of 30.01.90,

The design of the wave recorder is made up of the smelter and the associated load and weather vane. Yafig.Z depicts a structural diagram of the processing of informative signals, where 1 is the reference oscillator, 2 is the alternating current generator, 3 and 4 are the vertical accelerometers, 5 v the horizontal axis are oriented axes, 6.16 are adders, 7,

5 9, 13, 22 - dividers, 8,12, 18 - difference amplifiers 10,10 - double integrators, 11 - pefHcfpaiTop, 14-multiplier, 15,17t reference voltage sources, 20,21 - functional converters, 23 - quadrator

0 24-scale amplifier

The float 1 is rigidly connected with the accelerometers 3, 4, and 5 oriented mutually perpendicular to the accelerometers, as well as with a weather vane and a load. The 8th output of the alternating current generator 2 is connected to the input of the remote deviation coils of the accelerometers 3, 4 and 5. The outputs of the accelerometers 3 and 4 are connected by -co the adders of the adder b and the first differential amplifier 18. The output of the first differential

0 amplifier 18 through the first double integrator 19 and the first functional converter 20 are connected to the first input

yogrovozhodytyl 7, with its second input connected the output of the adder 6. The output of the divider

5 7, as well as the output of the first reference source. go for example 15 are connected through the second; differential amplifier 8. second divider 9: and a second double integrator 10 with a waveform profile recorder 11. The output of the first

0 of the double integrator 19 through the second functional converter 21 is connected to the first input of the fourth divider 22, and the output of the first functional converter 20 is connected to its second input.

5, the divider 22 is connected to the input of the multiplier 14 directly and through the quadrator 23 with the input of the second adder 16,; the second input of which is connected to the second reference voltage source 17. The output of the second adder W is connected to the second input of the second divider 9. The output of the third accelerometer 5 is connected to the third input of the second differential amplifier 8 through a series-connected third differential amplifier 12, the third divider 13 and a multiplier 14. The output of the second functional converter 21 is connected to the second input of the third difference amplifier 12 through a scale amplifier 24, and the output of the first functional converter 20 is connected to a second th input of the third divider 13.

The device operates as follows. In case of wind waves, the entire measuring system is oriented in such a way that the axis of the vane becomes parallel to the direction of wave propagation; The presence of a load ensures the stability of the structure and reduces its horizontal movements. The float 1 is rigidly connected to two vertically oriented accelerometers 3 and 4, which are spaced apart from the negro by the same distance in the plane of the wind vane. The third accelerometer 5, mounted in the center of mass, is oriented horizontally along the wave propagation.

The parameters of the harmonic signal supplied to the remote hatch coils of the accelerometers 3, 4 and 5 and its influence on the measurement process are similar to those considered in Example No. 1.

Accelerometers 3 and 4 give signals that include the following components:

Accelerometer 3.

1) it does not represent vertical acceleration a in aycosv (for example, with a positive sign, Fig. 4);

2) a g gcos v component of the acceleration of gravity (e.g., with a negative sign, Fig. 4); h; ; ,

3) component of horizontal acceleration a x axSinv (e.g. with a positive sign, Fig. 4);

4) component from the angular acceleration Li, where Li is the distance from the center of mass of the object to the first accelerometer (for example, with a positive sign, Fig. 4);

5) harmonic signal from the alternator ar Aasin in t, Accelerometer 4. ;

1) component of vertical ycVorein a in aycosv (respectively with a positive sign, FIG. 4);

2) component of the acceleration of gravity gcos v (respectively with the Negative sign, Fig. 4);

3) component of horizontal acceleration 3xslnv (respectively with a positive sign, fig.4);

4) component of angular acceleration a #. v Li, where L2 is the distance from the center of mass to the second accelerometer (in accordance with Fig. 4 with a negative sign);

5) a harmonic signal from an alternator ac A aslnwt.

The signal from the accelerometer 5 contains the following components:

1) axcos v component of horizontal acceleration (respectively with a positive sign, Fig. 4);

2) a component of a vertical acceleration a Hy aysln v (with a negative sign, respectively, Fig. 4);

3) component of the acceleration of gravity gsln v (respectively with the Positive sign, Fig. 4); 10 4) a harmonic signal from an alternator ac L asin ft) t.

Thus, the signals of the accelerometers 3, 4, and 5 can be described by the following expressions, respectively: 1 B.-.:.-.-. -, -. -. ., -, and aycos v - gcos v + axsln v + v Li + Л and xsinfwt;

a aycos v-gcos v + axsin v- vL2 + Yes 20xs1nft t;

xt.

a axcos v -aysin v + gsin v + Aasin

If the accelerometers are identical and the distance from the center of mass to the accelerometers 3 and 4 is equal to Li L, then the total signal from the accelerometers 3 and 4 generated by the adder 6 (with a transmission coefficient of 1/2) can be described by the expression:

a + a (ay-g) cosv + axslnv-f-Aasln cot.

The differential signal of the accelerometers 3 and 4, generated by the differential amplifier 18 having a gain of 1/2, in this case is written in the form:

40

aa l v

moreover, the coefficient L determines the sensitivity of the device according to the angular acceleration /. -. ....,. ::

To obtain information on ymyv, the signal from the differential amplifier 18 needs to be integrated twice. Thus, the output signal of the integrator 19 is proportional to the angle v, which the functional converters 20 and 21 transform

are called according to cosine functions

cosv and sinus sin v, respectively. The division of the signal from the adder 6 into the signal from the functional Converter 20 occurs in the divider 7, the output signal of which can be written in the form:

 + axtgv +.

cosv

The signal from the functional converter 21, which is proportional to the sine of the angle of inclination v through the scale amplifier 24 with a gain equal to the acceleration of gravity, is fed to one of the inputs of the differential amplifier 12, the second input of which is supplied by the signal from the accelerometer 5, Thus, the component will be compensated from the acceleration of free fall in the signal from a horizontally located accelerometer 5, the Signal from the differential amplifier 12 will be proportional to the following value:

Uia axcos v -aysln v + D asin an.

In the Divider 13, the signal is divided from the difference amplifier 12 into a signal proportional to the cosine of the angle of inclination from the functional converter 20:

Ui3 ax-aytg v + Yes

sin rut cos v

Then the signal from the divider 13 is fed to one of the inputs of the multiplier 14.

In the divider 22, the signals from the functional converters 20 and 21 are proportional to the cosine and sine of the angle of inclination, respectively, so that the output signal of the divider 22 is proportional to the tangent of the angle of inclination. Further, this signal is fed to the input of the quadrator 23 and to the second input of the multiplier 14, the output signal from which can be described by the following relationship:

 v -aytg2v +

+ Yes tgv

slnm cos v.

Subtraction of the signal proportional to the acceleration of free fall from the reference voltage source 15 and the signal from the multiplier 14 from the signal from the divider 7 is performed by the difference amplifier 8. Its output signal will be proportional to the following value:

Us ay (1 + tg2v) +

+ Aajia «i (1 + tgV).

Cosv

To eliminate the influence on the received signal of the angle of inclination v in the adder 16, the addition of signals from the quadrator 23 and from the source of reference

voltages proportional to, respectively, the square of the tangent of the angle of inclination v and the unit signal. In this case, the total signal supplied to one of the inputs of the divider 9 from the adder 16 will have the form:

Ui6 I + tg2 v.

At the second input of the divider 9, a signal is sent from the differential amplifier 8:

Ug av + yes

sin ft t I 4- tg v

COS V | + tg2 V

The signal from the divider 9, proportional to the vertical acceleration of the float, is integrated twice by the double integrator 10 and is recorded by the waveform profile recorder 11. When the signal from the divider 9 is double integrated, the component:

25

sinftjt 1 4- tgv cosv i + tg2v

will be filtered because the predetermined frequency a) lies above the measured frequency range of the wave.

As accelerometers, sensors of the DLUMM type (microminiature linear acceleration sensor) can be used.

Reference voltage sources, difference amplifiers and combiners can be

35 are based on operational amplifiers of the 140 series (see, for example, Likhachev V.D., Practical circuits for operational amplifiers x. - M.: Publishing house DOSAAF USSR, 1981, p. 80), multiplier, quadrator,

40 scale amplifier and dividers - based on 525 series microcircuits (see, for example, Aleksenko A.G., Kolombet E.A., Starodub T.I. Application of precision analog ICs, - M .: Radio and communication, 1981, p. 224). Integrators45 can be performed, for example, with frequency-dependent feedbacks that allow integration in a given frequency range (see the article Dubinsky Yu.V., Ferenets A.V. Inertial converter of vertical speed. In the book: Systems and elements of electrical equipment for aircraft. Interuniversity digest. Kazan, 1986. p. 89-92). Functional converters55 can be performed, for example, on the basis of analog-to-digital converter 572ПВ1, read-only memory device 568RE1 and digital-to-analog converter 572 ПА2.

A loop oscilloscope, a magnetic storage device, etc. can be used as a recorder. Thus, let alone the parameters of the sea; lvSh yayyu implemented on two examples, shows that / in the process of measurements ripOMexoflvi

measurements at low frequencies measured. : -u: Ts. .

TB | The economic and economic efficiency of the proposed method for measuring sea waves is to improve the accuracy of wave measurements in meteorological and oceanographic studies. D v i

F. Ormu of the invention

A method for determining the frequency and amplitude of sea wind waves, in which

Fieg

0

 generate signals from accelerometer sensors, compensate for the influence of the angle of inclination of their axis. Sensitivity relative to the vertical and generate an output signal proportional to the determined parameters of the waves; On the other hand, with the aim of increasing accuracy when generating signals from accelerometric sensors, they add an additional number of GarMoyichesk e signals f.c of frequency f lying in the Range f0 f fc. amplitude A equal to AO / K. where ft g is the value of the upper limit of the measured range of the Sea Wave Frequency ;;% is the natural frequency of the accelerometer; A Q accelerometer response threshold; K - xel sensitivity; eryometer .-; l-- - :; :: :::; - :. y;. :: -: ;;:;. .

 Ige - / -.

 /

nd