RU2518975C2 - Test bench for measurement of vibratory reaction moments in gyromotor - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: invention relates to instrumentation equipment, namely to instruments for the measurement of vibratory reaction moments of gyromotors. A test bench comprises a suspender, a chamber providing for the fixation of a gyromotor with its transverse or polar axes along the suspender axis, vibration measuring instrument in the form of the first magnetoelectric sensor with its windings being fixed in the device casing in the field of magnets set at the suspender axis and joined through a measuring amplifier with a signal measuring instrument and a power amplifier, the load to the latter is applied by the windings of the second magnetoelectric sensor set coaxially to the first sensor, the suspender is made as a shaft connected to the chamber and vertically installed in the bearings of the casing mounted on a base, current leads of the gyromotor are made as three springs with their opposite ends being joined with the chamber and the test bench body through contact plates.

EFFECT: improved accuracy and processability of control of gyromotor's vibratory reaction moments at the gyromotor production stage.

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Description

The invention relates to measuring equipment, namely to means for measuring vibrational reactive moments of gyromotors.

A known installation (analogue) is described in SU No. 325690, where a reference float electromechanical angular velocity sensor (DLS) is used as a measuring instrument of angular vibrations excited by a gyromotor installed in a float gyro unit. The controlled gyro unit is connected mechanically to the reference sensor and placed on a gasket, which plays the role of an elastic suspension, which allows the reference TLS to perceive and measure angular vibrations. In the reference TLS, the feedback from the precession angle sensor through the amplifier to the torque sensor is closed, the load resistor is connected through the ADC to the PC. The gyro motor of the controlled gyro unit is turned on, the gyro motor of the reference sensor is left not turned on, and the voltage across the load resistor as a function of time is measured for the reference TLS with a measuring device and, according to the results of the expansion of the voltage function in a Fourier series, a conclusion is made about the amplitudes of the variable component at individual frequencies that will be contained in the output signal of the TLS collected using a controlled gyro. The specified installation has uncertain dynamic characteristics and a significant moment of elastic resistance, which reduces the sensitivity of the system.

For the prototype adopted the installation described in RU 2427801 from 11.11.2009, depicted in figure 1. The installation comprises a suspension, a means of mechanical connection in the form of a technological chamber that allows fixing the gyromotor with the equatorial or polar axes along the suspension axis, means for measuring and processing the output signal from the angular vibration characteristics meter, made in the form of the first magnetoelectric sensor, the windings of which are connected through the measuring amplifier with the means signal measurements and are fixed on the device body in the field of magnets mounted on the suspension axis. The design of the installation with the assembly of the gyromotor in the technological case fixed in the position corresponding to the control of the frequencies of angular vibrations in the equatorial plane is presented.

The tested gyromotor 5 is installed in the housing 4, which is fixed in the collet 2 using the clamp 3. The collet 2 is a movable part of the installation, has an elastic suspension on 3 strings 7 through a locking device 6 to the housing 1 of the installation and is rigidly connected to the magnetoelectric system 8 sensor, the windings of which 9 are mounted on the housing. A centering stone support 10 is introduced to ensure uniform working gap of the magnetoelectric signal sensor. The power supply to the gyromotor is carried out through three metal strings 7 - installation suspension.

Thus, the control of the vibrational reactive moments of the gyromotors is carried out by fixing the tested gyromotor in the suspension of the installation when the rotor is oriented either by the axis of rotation along the vertical axis of the installation and control of angular vibrations around the polar axis of the rotor, or when the rotor is oriented by the equatorial axis along the vertical axis of the installation to control angular vibrations, arising around the equatorial axis of the rotor, oriented along the axis of sensitivity of the installation. Since in the latter case the gyro motor under test can simultaneously excite a number of frequencies, the signal of the installation sensor will be a complex periodic function.

The specified installation in figure 1 has the following disadvantages.

1. Direct measurement of the voltage from the output of the measuring amplifier in the absence of compensating feedback does not provide high accuracy for controlling the intensity (a number of amplitudes) of the vibrational moment around the suspension axis with unstable scale factors of the installation at fixed frequencies.

2. The elastic suspension on metal strings does not provide a constant orientation of the suspension axis and, therefore, the gap in the magnetoelectric sensor, affecting the stability of the scale factor of the installation at fixed frequencies.

3. Scaling the installation using a reference gyromotor and a number of frequencies of a single-phase supply voltage is a rather laborious technological process.

The objective of the invention is to increase the accuracy and manufacturability of the control of vibrational reactive moments of gyromotors at the stage of its manufacture by introducing the inventive stand.

The technical result is achieved by the fact that in the device containing the suspension, the means of mechanical connection in the form of a technological chamber that allows the gyromotor to be fixed with the equatorial or polar axes along the suspension axis, means for measuring and processing the output signal from the angular vibration characteristics meter, made in the form of the first magnetoelectric sensor, the windings of which are connected through a measuring amplifier with a means of measuring the signal and mounted on the device’s body in the field of magnets, installed On the suspension axis, a second magnetoelectric sensor is introduced, mounted coaxially and similarly attached to the first magnetoelectric sensor, a power amplifier, the load of which is the windings of the second magnetoelectric sensor, and current leads with the possibility of changing the stiffness coefficient, while the input of the power amplifier is connected to the output of the measuring amplifier, and the suspension is made in the form of a shaft connected to the camera and vertically mounted in the bearings of the housing, current leads to the gyromotor are made in the form three springs, the ends of which through the contact boards are joined with the technological chamber and the housing of the device.

Figure 2 presents the functional diagram of the proposed stand, with the orientation of the gyromotor rotor with the equatorial axis along the suspension axis, containing the following functional units: gyromotor 1 in the form of a synchronous hysteresis motor, process chamber 2, suspension shaft 3, bearings 4, magnets 5, 7 and windings 6, 8, respectively, of the first and second magnetoelectric sensors (the second sensor is mounted coaxially and similarly to the first sensor - the winding is mounted on the stand body, and the magnet is mounted on the suspension shaft), case 9, stand 10, contact circuit boards 11, springs 12 (current leads with adjustable angular stiffness), measuring amplifier 13, power amplifier 14, signal measuring means (PC 16 and analog-to-digital converter 15, through which the output signal from the first sensor is supplied to the PC), the gyromotor is supplied from a power source in the form of a processor module (based on ADUC 7026) (not shown in FIG. 2).

The designs of the first and second magnetoelectric sensors are identical to the design of the moment sensor of the reference CRS described in SU No. 325690.

The power amplifier (Fig. 3), configured to change the gain, connected to the terminals of the winding of the second sensor by an output, contains an amplifier U1, an inverting input through a resistor R1 connected to the output of the measuring amplifier (through resistor R2, it is possible to connect to the output of a sinusoidal voltage generator ) The output of amplifier U1 through amplifier U2 (an emitter follower according to Darlington's circuit) is connected to the beginning of the winding of the second sensor, the end of which is connected through a reference resistor RH to a common bus, and also through a resistor R _n to the inverting input of amplifier U1. The current i _dm through the second sensor and the voltage U _oc on the resistor R _{n are} determined by the formulas:

, $$U_{oc}=\frac{R3}{R1}\left(U_f-\frac{R1}{R2}{U}_{Г}\right)$$

, $$i_{dm}=\frac{R3+R_n}{R_{n}R\mathrm{one}}\left(U_f-\frac{R\mathrm{one}}{R2}{U}_G\right)$$

, $$U_{oc}=\frac{R3}{R\mathrm{one}}\left(U_f-\frac{R\mathrm{one}}{R2}{U}_G\right)$$

,

where R _n <(R1 and R3), R3 is the control resistor, U _G is the reference voltage from the sinusoidal voltage generator, U _f is the output voltage of the angular vibration meter.

The stand works as follows:

When scaling a bench using an unbalanced rotor of a reference gyromotor, one value of the scale factor from a number of fixed frequencies of a single-phase supply voltage is required if the following condition is satisfied at these frequencies: M _f -M _dm = 0, in the absence of a frequency dependence of compensating voltage feedback U _f , at this U _f = M _dm / (K · K _{mind dm} / R _n where K _{mind dm} · K / KH -. scaling factor at fixed frequencies on which to determine the vibration characteristics of the excited GM thereby decreases rudoemkost prediction process variable zero CRS signal component.

где К_ду, К_у - крутизна по угловой скорости ω_f для первого датчика и коэффициент усиления измерительного усилителя, С, J, ν - угловая жесткость пружины, момент инерции и коэффициент демпфирования по оси подвеса стенда. Следовательно, масштабный коэффициент у стенда без обратной связи зависит от частоты вибраций гиромотора (угловой скорости).The accuracy of determining the scale factor increases with an unstable slope of the angular vibration characteristics meter made in the form of the first magnetoelectric sensor. Moreover, from the equation of oscillation of the suspension (without feedback) we have: $$U_f=M_f\cdot \frac{K_{d\mathrm{at}}{K}_{\mathrm{at}}}{\sqrt{{\left(C-J{\omega }_f^2\right)}^2{\left(\nu {\omega }_f\right)}^2}}{\omega }_f,$$

where K _d , K _y is the slope of the angular velocity ω _f for the first sensor and the gain of the measuring amplifier, C, J, ν is the angular stiffness of the spring, the moment of inertia and the damping coefficient along the axis of the suspension stand. Therefore, the scale factor of the stand without feedback depends on the frequency of vibrations of the gyromotor (angular velocity).

Effective control of the amplitude-frequency characteristics of the device is possible by supplying a reference voltage from a sinusoidal voltage generator to the windings of the second magnetoelectric sensor. In this case, the voltage frequency corresponds to a number of fixed frequencies from the results of the expansion of the measured voltage in a Fourier series.

To implement the method for predicting the variable component of the output of the TLS (ω _f ) according to the characteristics of the angular vibrations (M _f ) excited by the gyromotor, the structural diagram of the stand and the transfer functions of the closed and open systems shown in Fig. 4 are used.

The inventive stand relates to closed systems of automatic control, where the control action is the moment M _dm , is formed depending on the controlled voltage U _f , the change of which occurs under the influence of a disturbing moment M _f .

The generated moment M _dm is subtracted from the moment M _f with negative (compensating) feedback connecting the system input (stand suspension) with its output (second sensor) through the first sensor, measuring amplifier, power amplifier, and second sensor connected in series. The stand is referred to as open control systems, if the moment M _{dm is} not subtracted from the moment M _f .

The structural diagram in figure 4 is formed in accordance with the operator matrix form of the equation of oscillation along the axis of the suspension:

$$|\; |\; |\begin{array}{cc}{a}_{\mathrm{eleven}}& a_{12}\\ a_{21}& a_{22}\end{array}|\; |\; |\cdot |\; |\; |\begin{array}{c}\varphi \\ i_{dm}\end{array}|\; |\; |=|\; |\; |\begin{array}{c}{M}_{\Sigma }\\ O\end{array}|\; |\; |$$

- суммарный момент по оси подвеса стенда при работе с испытуемым гиромотором, $$M_{\Sigma }=M_f^U+M_f^{э}$$

- суммарный момент по оси подвеса стенда при работе с эталонным гиромотором, M_f - момент по оси подвеса стенда, обусловленный вибрацией гиромотора в широком диапазоне спектра частот; $$M_f^U$$

- момент по оси подвеса стенда при подаче синусоидального напряжения U_Г на второй вход усилителя мощности; $$M_f^{э}$$

- момент по оси подвеса стенда при установке в камеру эталонного гиромотора с грузами; φ - угол при колебании камеры по оси подвеса; i_дм - ток через обмотки второго магнитоэлектрического датчика; $$M_{\Sigma }=M_f+M_f^U$$

- total moment along the axis of the suspension of the stand when working with the tested gyro motor, $$M_{\Sigma }=M_f^U+M_f^{\mathrm{uh}}$$

- the total moment along the axis of the suspension of the stand when working with a reference gyromotor, M _f - the moment along the axis of the suspension of the stand, due to vibration of the gyromotor in a wide range of frequency spectrum; $$M_f^U$$

- the moment along the suspension axis of the stand when applying a sinusoidal voltage U _G to the second input of the power amplifier; $$M_f^{\mathrm{uh}}$$

- the moment along the axis of the suspension of the stand when installing a standard gyro motor with loads in the chamber; φ is the angle when the camera oscillates along the suspension axis; i _dm is the current through the windings of the second magnetoelectric sensor;

a ₁₁ = J · s ² + ν · s + C, where J, ν is the moment of inertia and damping coefficient along the suspension axis (ν is determined by the harmonious linearization of friction in the bearings); C is the adjustable angular stiffness of the current supply spring, while the stiffness of the springs wound from steel wire and working in tension, or leaf bend springs, is regulated by moving the contact board parallel to the suspension axis;

a ₂₁ = s · To _do · K _y · To _mind / R _p , where s = jω, To _do - the steepness of the characteristics of the first sensor according to the angular velocity of oscillations along the suspension axis; To _y - the gain of the measuring amplifier, K _mind - adjustable gain of the power amplifier; R _p is the reference resistor at the output of the power amplifier; a ₁₂ = K _dm , where K _dm is the slope of the moment characteristic of the second sensor; a ₂₂ = -1.

To analyze the stability of the stand, the transfer functions of an open and closed system are used (s = jω is the Laplace operator): W (s) = W ₁ (s) · W ₂ (s), Ф (s) = W (s) / (1+ W (s))

From the analysis of figure 4 it follows that W ₁ (s) = K _mind · K _dm / R _n ;

W ₂ (s) = s · To _do · K _y / (J · s ² + ν · s + С)

From the analysis of the phase-frequency characteristic of the open-feedback stand, it follows that there is no level crossing of -180 °, therefore, in the closed state, the stand has sufficient stability margins (phase margin of 90 °). From the analysis of the logarithmic frequency response of the stand with open feedback, it follows that there are lower and upper cut-off frequencies that are set taking into account the minimum and maximum of the fixed frequencies of vibrational vibrations by adjusting the gain (K _y , K _mind ) and spring stiffness (C) in the stand while the stability margins are practically unchanged.

Using the transfer function Φ (s), the amplitude-frequency characteristic (AFC) of the stand layout with compensating feedback is constructed.

From the analysis of the frequency response of the test bench with feedback, it follows that at level 0.7 there are lower and upper passbands corresponding to the lower and upper cutoff frequencies.

To assess the accuracy and manufacturability of controlling the vibrations of the gyromotor, by introducing the proposed bench, the transfer functions of the closed system for the output signal U _f and for the moment M _dm by the disturbing effect M _f : Y (s) = W ₂ (s) / (1 + W (s)), Φ (s) = W (s) / (1 + W (s))

From a comparative analysis of Y (s) and φ (s) taking into account W ₁ (s) it follows:

, $$M_f^U$$

аналогичны АЧХ стенда с обратной связью;- frequency characteristics for the measured voltage U / and the compensating moment M _dm according to the moments M _f , $$M_f^{\mathrm{uh}}$$

, $$M_f^U$$

similar to the frequency response of a feedback stand;

- the scale factor of the stand is determined from the expression for Y (s) and is at fixed frequencies - K _mind · K _dm / R _n . Therefore, taking into account the frequency response of the test bench with feedback, when scaling, one value of the scale factor at any fixed frequency in the interval from the lower to the upper cutoff frequencies will be required;

- periodic control of the frequency response of a closed system is possible by the ratio of the amplitude of the measured voltage U _f to the amplitude of the voltage U _G from the sinusoidal voltage generator;

- stability of a number of scale coefficients of the stand in the absence of the compensating feedback given by the expression for the transfer function W ₂ (s), where the slope K _dy first magnetoelectric transducer and depends on the stability of the gap between the magnets and the coils of the sensor in the elastic suspension.

на фиксированных частотах определяется согласно выражению: $$M_f^{don}=A^{-1}\left(2\pi f\right)\cdot H\cdot {\omega }_f^{don}$$

, где A(2πf) - значения АЧХ датчика угловой скорости для компенсирующего момента по гироскопическому моменту; H - кинетический момент; $$M_f^{don}$$

- допустимая переменная составляющая нулевого сигнала ДУС, приведенная к угловой скорости по оси чувствительности.In addition, the permissible value of the vibration moment $$M_f^{don}$$

at fixed frequencies is determined according to the expression: $$M_f^{don}=A^{-\mathrm{one}}\left(2\pi f\right)\cdot H\cdot {\omega }_f^{don}$$

where A (2πf) is the frequency response of the angular velocity sensor for the compensating moment by the gyroscopic moment; H is the kinetic moment; $$M_f^{don}$$

- the permissible variable component of the zero signal of the TLS, reduced to the angular velocity along the sensitivity axis.

Thus, a stand for measuring vibrational reactive moments of a gyromotor is declared, comprising a suspension, a camera that secures the gyromotor with either the equatorial or polar axes along the axis of the suspension, the first magnetoelectric sensor, the winding of which is connected through a measuring amplifier to a signal measuring device and mounted on the bench body in field of a magnet mounted on the axis of the suspension. A distinctive feature of the stand is that a second magnetoelectric sensor is introduced, mounted coaxially and similarly attached to the first sensor, a power amplifier connected to the winding of the second sensor by an output, and connected to the output of the measuring amplifier by an input, and current leads with the possibility of changing the stiffness coefficient, while the suspension is made in the form of a shaft connected to the camera and installed in the bearings of the stand body, and the ends of the current leads are joined to the camera and the stand body.

The technical result of the invention is to increase the accuracy of determining the scale factor and manufacturability of control of vibrational reactive moments of gyromotors, which reduces the complexity of the method for predicting the variable component of the zero signal of the TLS.

Claims (1)

A stand for measuring vibrational reactive moments of a gyromotor, containing a suspension, a camera that secures the gyromotor with either the equatorial or polar axes along the axis of the suspension, the first magnetoelectric sensor, the winding of which is connected through a measuring amplifier with signal measuring means and mounted on the stand body in the magnet field installed on the suspension axis, characterized in that a second magnetoelectric sensor is introduced, coaxially mounted and similarly attached to the first sensor, the amplifier m the output connected to the winding of the second sensor, and the input connected to the output of the measuring amplifier, and current leads with the possibility of changing the stiffness coefficient, while the suspension is made in the form of a shaft connected to the camera and installed in the bearings of the stand housing, and the ends of the current leads are connected to the camera and the body of the stand.

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