RU2750180C1 - Method for reducing vibration errors of gyro platform using dynamically tuned gyroscopes - Google Patents

Abstract

FIELD: gyroscopic instrumentation.

SUBSTANCE: invention relates to the field of gyroscopic instrumentation. Before installing the dynamically tuned gyroscope into the gyro platform, its autonomous vibration studies are carried out using a vibration stand, the platform of which has an elastic suspension. At the same time, the speed of the gyroscope drift from self-swinging caused by periodic changes in the components of the natural vibration spectrum of the ball-bearing support of its drive, the spectral composition of its own vibration and the magnitude of the vibration components of this spectrum, natural resonance frequencies due to the axial and radial stiffness of its elastic suspension are determined. Gyroscopes installed in the gyro platform are matched with taking into account the requirements imposed on the spacing of the natural frequencies of the two gyroscopes from each other, the values of the natural vibration components of the vertical and course gyroscopes located in the specified regions near the resonance frequencies of the course and vertical gyroscopes, respectively, the values of the drift velocities from the self-swinging of the vertical and heading gyroscopes.

EFFECT: reduction of vibration errors of the gyro platform from the own vibration interaction of the DTG at the same tuning frequency of the generators supplying the gyro drives for all manufactured gyro platforms.

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Description

The invention relates to the field of instrumentation, mainly gyroscopic, and can be used in the production of gyro platforms for inertial navigation systems on dynamically tuned gyroscopes (DGS).

There is a known method of decreasing the drift speed of mechanical gyroscopes caused by the effect of linear vibration by increasing the equal rigidity of the suspensions of their rotors (see, for example, the book by E.N. Nikitin and others under the general editorship of DS Pelpor "Gyroscopic systems. Part III. Elements of gyroscopic devices ", M, 1972, pp. 117-121), when with an equal rotor suspension structure and with equal damping coefficients along the axis of its own rotation and the radial axis, there is no constant elastic unbalance component and, accordingly, the drift speed caused by it is absent. However, due to design and technological limitations, the absolute fulfillment of these conditions in practice is not ensured and mechanical gyroscopes, in particular dynamically tuned gyroscopes, have errors when exposed to linear vibration, which causes errors in the gyro platforms in which they are used.

The prototype is taken as a method of adjusting a dynamically tuned gyroscope (see inventor's certificate SU No. 1598615 according to class G 01 C 19/22 dated June 8, 1990). In this method, it is proposed to reduce the error of a dynamically tuned gyroscope due to the effect of its own linear vibration generated by the operating ball bearing support of the gyroscope drive. In this case, the gyroscope has an unequally rigid elastic suspension of the rotor and damping of its vibrations. Due to the spread of parameters in the serial production of dynamically tuned gyroscopes, their resonant frequencies due to the axial and radial stiffness of the elastic suspension are not the same and have a spread (2-5)% of the average frequency. Therefore, for a certain part of the produced DNG, the resonance frequency of the elastic suspension may coincide with the frequency of one of the components of the natural vibration spectrum of the ball bearing support. As a rule, the vibration acceleration of the components of the natural vibration spectrum, located in the resonance frequency range of the elastic suspension, is unstable and changes with a period of (5-50) s due to different rotation speeds of the separators of the two ball bearings of the DNG drive. In the DNG with the same resonance frequencies of the elastic suspension and natural vibration, resonant oscillations of the DNG drift velocity (self-swinging) occur, which reduce its accuracy. Since the frequencies of the natural vibration of the ball bearing support are proportional to the frequency of rotation of the drive shaft, then by changing the frequency of rotation of the shaft by changing the frequency of the generator supplying the synchronous electric motor of the DNG drive, it is possible to shift the frequency of the natural vibration component relative to the resonance frequency of the elastic suspension, thereby eliminating the fluctuations in the speed of its drift. After determining the operating frequency of rotation of the DNG rotor, which minimizes the fluctuations in the drift speed from the effect of its own vibration, the DNG is tuned to the natural frequency by sequentially determining the frequency detuning and changing the moments of inertia of the cardan frames.

In the known method, the displacement of the frequency of the natural vibration component relative to the resonance frequency of the elastic suspension of the DNG is produced by changing the frequency of the generator supplying the synchronous electric motor of the gyroscope drive. For each DNG, in which a spacing of these frequencies is required, in this case there will be practically its own tuning frequency of the supply generator, which is different from other gyroscopes, and generators with different operating frequencies will be installed in the platform. Tuning the generators to different frequencies complicates the process of their release and, when replaced in the DNG gyro platform, the generator must also be replaced, which increases the cost of repair. The known method solves the problem of installing in the gyro platform two DNG with a reduced drift speed from self-swinging. However, the gyro platform on which two DNGs are installed, due to the finite rigidity of the structural elements of its gimbal suspension, is an elastic foundation. As part of the gyro platform, each DNG is affected by an external vibration caused by another DNG, and its own vibration. In the known method, a proposal is made to reduce the speed of the DNG drift from self-swinging caused only by its own vibration, however, in this case, errors occur in the gyro-platform caused by the mutual vibration influence of the DNG on each other, which are not taken into account in this method.

The technical result that can be obtained with the implementation of the present invention is to reduce the vibration errors of the gyro platform from the own vibration mutual influence of the DNG at the same tuning frequency of the generators supplying the gyro drives for all manufactured gyro platforms.

The technical result is achieved by the fact that in the known method of adjusting a dynamically tuned gyroscope, which includes measuring, when dynamically tuned gyroscopes are released, their drift velocity from self-swing, for which the amplitude of fluctuations in the drift velocity caused by a periodic change in the components of the spectrum of the own vibration of the ball bearing support of the gyroscope drive is determined, in addition before installation the gyroscope in the gyro platform, it is placed on the platform of the shaker, which has an elastic suspension, and when measuring the drift velocity from self-swing, the spectral composition of its own vibration and the values of the vibration components of this spectrum are found when the shaker is turned off, then the shaker is turned on and the gyroscope drift speed is measured when it is subjected to linear vibration in the frequency range from 800 Hz to 1100 Hz and according to the greatest deviation of the drift speed from the level of the drift speed without the influence of external vibration, the first and second resonance frequencies are found, due to determined by the axial and radial stiffness of the elastic suspension of the gyroscope, after which the gyroscopes installed in the gyro platform are matched in such a way that the resonance frequencies of one gyroscope should differ from the resonance frequencies of another gyroscope by at least 20 Hz, while the vertical gyroscope of the gyro platform should not have in the range of ± 15 Hz near the resonance frequencies of the course gyroscope components of its own vibration with vibration acceleration higher than 0.04 g, and the course gyroscope should not have in the range of ± 15 Hz near the resonance frequencies of the vertical gyroscope of natural vibration components with vibration acceleration above 0.02 g, and the drift speed from self-swinging should be no more than 0.2 ° / h for a vertical gyroscope and no more than 0.4 ° / h for a heading gyroscope.

Thus, the proposed method for reducing the vibration errors of the gyro platform on the DNG has the following differences from the known method:

- a new action is introduced, associated with the determination of the frequencies of the spectral components of the own vibration of the DNG and their values;

- a new action is performed to determine the resonance frequencies of the elastic suspension as a result of the impact on the DNG of the external vibration of the shaker;

- a new quality is proposed for reducing the vibration errors of the gyro platform on the DNG, associated with a decrease in vibration errors caused by the mutual vibration influence in the gyro platform of two DNGs on each other;

- based on practical experience, the following criteria were proposed: the separation of the resonant frequencies of two DNGs in the gyro platform; the frequency range in the area of resonant frequencies of the vertical and directional DNG, which is critical to vibration interaction; values of permissible drift velocities from self-swinging for vertical and directional DNG;

- it is proposed to use power generators for electric motors of gyro drives, which are always tuned to the same frequency, while reducing the errors of the gyro platform on the DNG from its own vibration accelerations.

The proposed method is used in technical documentation for a gyroscope with an internal gimbal GVK-6 in the form of technical requirements 6D2.562.030 D2.6 for the selection of GAK-6 in pairs for the gyro platform.

Using the proposed method allows you to improve the technical characteristics of the gyro platform on the DNG, in particular, to reduce the "hull" drift speed caused by a change in the rigidity characteristics of the gimbal of a stabilized platform with DNG, when changing its orientation relative to the body of the gyro platform, due to a change in the spatial orientation of the object.

Claims (1)

A method for reducing vibration errors of a gyro platform on dynamically tuned gyroscopes, including measuring, when dynamically tuned gyroscopes are released, their drift rate from self-swing, for which the amplitude of fluctuations in the drift velocity caused by a periodic change in the components of the spectrum of its own vibration of the ball bearing support of the gyroscope drive is determined, characterized in that before installing the gyroscope in the gyro platform, it is placed on the platform of the vibration stand, which has an elastic suspension, and when measuring the drift speed from self-swing, the spectral composition of its own vibration and the values of the vibration components of this spectrum are found when the vibration stand is turned off, then the vibration stand is turned on and the speed of the gyroscope drift is measured when it is subjected to linear vibration in the range frequencies from 800 to 1100 Hz and according to the greatest deviation of the drift speed from the level of the drift speed without the influence of external vibration, the first and second resonance frequencies are found, due to the axial and radial stiffness of the elastic suspension of the gyroscope, after which the gyroscopes installed in the gyro platform are matched in such a way that the resonance frequencies of one gyroscope differ from the resonance frequencies of another gyroscope by at least 20 Hz, while the vertical gyroscope of the gyro platform should not have in the range ± 15 Hz near the resonance frequencies of the course gyroscope of its own vibration components with vibration acceleration above 0.04 g, and the course gyroscope should not have, in the ± 15 Hz range, near the resonance frequencies of the vertical gyroscope of its own vibration components with vibration acceleration above 0.02 g, and the drift velocity from self-swing should be no more than 0.2 ° / h for a vertical gyroscope and no more than 0.4 ° / h for a heading gyroscope.