RU1820214C - Laser gyroscope - Google Patents

Abstract

The invention relates to laser gyroscopy. The aim of the invention is to reduce the temperature drift from the difference in the coefficients of thermal expansion and averaging of the coupling of counterpropagating waves. The goal is achieved in that the monoblock and the elastic support 2 are made monolithic. 2 ill.

Description

The invention relates to laser gyroscopy and can be used to create a high-precision sensor for angular velocity and angle of rotation in an inertial navigation system.

The aim of the invention is to reduce the temperature drift from the difference in the coefficients of thermal expansion and averaging of the coupling of counterpropagating waves.

In FIG. 1-3 shows the proposed gyroscope ..

In FIG. 1-3 indicate: 1 - a monoblock of a ring laser with channels for laser radiation and mirrors; support 2 (gyroscope case); additional identical holes 3; sections of monoblock 4 with parallel walls; ring optical circuit 5; attachment point of monoblock 6. Nafig, 1 not shown: active medium with excitation elements; output optical system; vibration generating means (vibration motor); power supply and information processing units.

The gyroscope works as follows.

In the ring cavity, two counter-traveling light waves of the same frequency are formed due to the excitation of the active medium. When the resonator rotates, the optical paths of the light waves moving in and against the rotation differ from each other, which leads to a difference in the frequencies of the counterpropagating waves in the ring laser. The output optical system and the information processing unit converts the frequency difference of the light waves into an output electric | a signal whose frequency is proportional to the angular velocity of the gyroscope. However, due to the coupling of counterpropagating waves in the resonator, the gyroscope is not sensitive to low input angular velocities. To exclude the influence of -; no deadband for accuracy; The KLG uses the so-called frequency stand - alternating angular oscillations of the KLG resonator around its sensitivity axis, in which the gyroscope is removed from the dead zone due to angular oscillations most of the time. To enable the creation of monoblock angular oscillations

00

y o y

Jv

additional openings in the monoblock are used, located inside the optical circuit symmetrically with respect to the attachment point of the monoblock to the support and symmetrically with respect to the monoblock, the axis of the holes parallel to the sensitivity axis of the gyroscope, and the bridges between adjacent holes have sections with walls parallel to each other. Such a system of holes forms blades in the monoblock (portions of the monoblock between holes with parallel walls) having certain elastic properties, which allows angular vibration of the monoblock. In FIG. Figure 16 shows a variant of securing a monoblock in a gyroscope case, in which the monoblock is fixed (by gluing, soldering) on a support made in the form of an axis entering the monoblock’s hole, the axis of the support being parallel to the gyro sensitivity axis and passing through the center of symmetry of the additional holes. Fig. 16 shows a variant of double-sided fixing of the monoblock in the gyroscope case, the connection is made by gluing or soldering the monoblock with the support (or additional protrusions of the monoblock with the support).

As already mentioned, a monoblock is usually made of quartz or ceramic, and Invar can serve as the material of the vibration suspension or support. When the temperature changes, it is necessary to compensate for the difference in the elongations AI R (a 1 - a g), where R is the contact radius of dissimilar materials, a. - KTP t-ro material. The gain in D I compared with the prototype is

Ј - dr - - - where R1 is the radius of the support in

version Ra - the radius of the ring in the prototype. For LTN-90 type CLG with a perimeter of 30 cm, mm, RI can be made Ri i 6 mm. Thus, the gain in the created deformations will be Ј 5 times in comparison with the prototype.

Thus, the meaning of this technical solution lies in the fact that the vibro-suspension is actually formed due to the presence of jumpers between the holes (blades) of the one-piece monoblock, i.e. there is no KTP difference between the materials of the vibro-suspension and the monoblock and, therefore, there is no thermal stress. The contact area of the monoblock with the support in this case has significantly smaller linear dimensions than in the presence of a vibro-suspension of radius R as in the prototype. The contact of the monoblock with the support occurs in the center of symmetry of all the holes, which should optimally

coincide with the axis of symmetry of the monoblock and

center of inertia. As a result of this being. The voltages transmitted to the monoblock are substantially reduced and symmetrized, and therefore, the thermal stability of the optical KLG circuit is increased.

It is known that the scale factor of CLG is non-linear. A consequence of this is the dependence of the accuracy of the KLG (drift) on the amplitude (as well as the shape and frequency) of the angular frequency base. This imposes requirements on the stability of the amplitude-frequency characteristics of the elastic element and the symmetry of the angular oscillations (amplitude of the stand) with respect to the equilibrium position.

For this purpose, in this technical solution, the monoblock is made with additional holes of identical shape, located symmetrically with respect to the attachment point to the support and the monoblock itself. The parallel parallel spring sections between the holes 5 are also located symmetrically with respect to the fixing point and the monoblock.

In addition to the symmetrization of angular oscillations, this also balances the thermal

0 flow between the monoblock and the support (gyroscope case). Consequently, the change in the size of the monoblock during its heating after switching on or when the external conditions change, as well as the thermal processes of mass transfer in the gas active medium, will proceed more uniformly, without disturbing the shape of the optical circuit and causing the Langmuir effect in the gas medium. Although specific estimates are here

It is difficult to give, but it is obvious that the positive effect of increasing accuracy is taking place.

The manufacture of a number of additional holes having the same shape simplifies the design of the monoblock, since the same holes are more technological in manufacturing.

To assess the real stiffness parameters of the monoblock jumpers according to the proposed technical solution, we present the four-blade design shown in Fig. 1 as four rigidly connected parallel to the gyroscope body connected in parallel with one

5. by the end of the beam of section bxh and length I, with elastic modulus E and permissible stress u, the free ends of which are loaded with mass m (monoblock). With a small amplitude of oscillations of mass m, when they can be considered linear, it is known

the formula for the frequency f of oscillations of such a system:

1 k v4 f - - (-), where m is oscillating with

mass, k — coefficient of elasticity of a system of four beams. From the theory of resistance of materials, formulas are known for calculating the coefficient of elasticity of such a system: k

3EI i-s.

where i

bhj

moment of inert-o. 12

not a beam. Thus, the frequency of such an elastic system of beams:

, 1-., 12E1 chu &

2p

(

mlj

)

We give the data for Invar and Quartz.

AND ABOUT

kg / m2, kg / m2,

For Invar: 510, 3.0-107 kg / m2;

for quartz: 5-109 -1.2-TO7 kg / m2.

For a beam structure close to the real parameters of the KL G vibro-suspension, type LTN-90, b "30 mm, h 3 mm, mm, m 0.5 kg, the oscillation frequency of the Invar vibro-suspension will be time" 210 Hz. A similar frequency can be obtained on smaller quartz beams (jumpers): mm (instead of mm for invar) fKBapn 200 Hz.

In order to create an effective frequency stand, it is necessary to ensure the angular oscillations of the monoblock for several angular minutes and the strength condition must not be violated:

M W a

where M d t - the moment that occurs

when bending the beam at an angle p:. . a - permissible voltage;

W

bh

is the moment of resistance of the beam section.

For the above parameters of vibro-suspension and jumper, the reserve ratio

N-ff strength% -ini- at a vibration amplitude of 1 arcmin will be: for Invar% 2,3 10 2: for Quartz% 1.4 102

i.e. in both cases, the structures satisfy the strength requirement with a margin of more than 100 times.

From the point of view of manufacturing the indicated 5 CLGs, a monoblock design with single jumpers is also more preferable, as compared to an inserted vibro-suspension, it is performed due to the same drilling and milling operations of a mono-10 block in a single manufacturing process, whereas an inserted vibro-suspension usually has a complex shape and requires in the manufacture of electrical discharge machining. :

15 We also note that the system of holes in the KLG monoblock, formed according to this technical solution, forms elastic blades for the entire thickness (height) of the monoblock, while maximum stiffness is achieved for parasitic (conical) vibrations with respect to the axes that do not coincide with the sensitivity axis of the monoblock ( KGL).

Claims (1)

The presence of monoblock sections between 25 additional holes having walls parallel to each other allows using them to form piezoelectric motors creating angular vibration of the monoblock. To this end, piezoceramic plates are glued to the opposite walls of the flat bridges between the holes. A similar bimorph structure, when applied to it, is capable of bending. The creation of piezod35 actuators on non-planar surfaces is difficult and ineffective. SUMMARY OF THE INVENTION A laser gyroscope comprising a ring laser with a resonator made in 40 in the form of a monoblock, with an output optical system and with an elastic support mounted on the basis of the gyroscope, the elastic support having at least two identical holes located symmetrically inside the optical circuit 45 relative to the location of the monoblock, the axis of the holes parallel to the axis of sensitivity of the gyroscope, jumpers between adjacent holes we have sections with parallel walls to each other, characterized in that, in order to reduce the temperature drift from the difference in the coefficients of thermal expansion and sredneni communication counterpropagating waves, and resilient monoblock 55 support made monolithic. 1 6 N w Figure 1