RU2543706C1 - Microacoustic mechanical gyroscope - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: microacoustic mechanical gyroscope comprises a base, a structure of inertia masses, placed in staggered order, piezoelectric converters and measurement comb transducers of the total field of surface acoustic waves from the regular structure of inertia masses. On the outer surface of the bearing base there is a thin film applied from piezoelectric with installed regular structure of inertia masses and measurement comb transducers for each of directions of rotation. At the same time the measurement comb transducers are placed symmetrically relative to the position of the regular structure of inertia masses and perpendicularly to axes of rotation of the bearing base. On the inner surface of the bearing base there is a trapezoidal ledge, the larger base of which faces the external surface of the bearing base, active piezoelectric converters are installed symmetrically to each other on the side surfaces of the trapezoidal ledge.

EFFECT: invention provides for conversion of angular speeds of rotation of a bearing base into electric signals of simultaneously two axes of rotation.

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Description

The invention relates to acoustoelectronic devices designed to convert the angular velocity of rotation of the base into an electrical signal, and can be used in navigation systems, orientation and control of various moving objects.

Known analogues of a microacoustic mechanical gyroscope, proposed, for example, in [1] (Patent of the Russian Federation No. 2387951 "Piezoelectric gyroscope" / VA Kalinin, VD Lukyanov, VA Shubarev, VA Melnikov, application No. 2009109735/28 dated 03/17/2009; published on 04/27/2010 Bull. No. 12), [2] (Patent of the Russian Federation No. 2390727 “Gyroscope on surface acoustic waves” / V. A. Kalinin, V. D. Lukyanov, V. A. Shubarev, VA Melnikov, application No. 2009109734/28 dated 03/17/2009; published May 27, 2010, Bull. No. 15) containing a supporting dielectric base with a piezoelectric plate mounted on it a trica, on one side of which a regular structure of inertial masses is applied, an active interdigital transducer (IDT) with a reflecting structure, exciting surface acoustic waves (SAWs) in one direction and measuring IDTs of the total surfactant field located in the perpendicular direction from the regular structure of inertial masses, consisting of surfactant fields that are diffractive and signal from the Coriolis forces, according to [1] opposite to the active IDT after a regular structure of inertial masses, an absorbing ID is applied to the plate the outputs of which are electrically connected by conductors with complex and adjustable load resistance or, according to [2] opposite to the active IDT, after a regular structure of inertial masses, a surfactant-absorbing layer with a reflection coefficient close to zero is applied to the piezoelectric plate and made in the form of a wedge with a tip directed to regular structure of inertial masses.

A significant drawback of these analogues, which impedes the practical use of the gyroscope, is the limitation of its functionality, due to the fact that this device provides registration of the angular velocity of rotation of the carrier base relative to only one direction of rotation. To register angular velocities with respect to two directions of rotation of the bearing base, it is necessary to additionally install a second similar gyroscope on it, which leads to a complication of the structure and an increase in its cost.

In terms of features, the closest analogue of the proposed device, taken as a prototype, is a microelectromechanical gyroscope described in [3] (US Patent No. 6984332 B2, H01L 21/00, G01P 3/00, 2006.01.10, VK Varadan, Pascal B. Xavier , William D. Suh, Jose A. Kollakompil, Vasundara V. Varadan / "MICRO-ELECTRO-MECHANICAL GYROSCOPE"), which contains a piezoelectric plate, on one side of which a regular structure of inertial masses is applied in a checkerboard pattern and in antinodes of a standing surfactant, active IDT with reflective structures, exciting surfactants in one direction, and perpendicular yarnom direction measuring IDT SAW total field from the regular structure of the inertial mass, and consisting of a diffraction signal from the Coriolis force fields surfactant. The principle of operation of the prototype device is that the regular structure of inertial masses arranged in a checkerboard pattern applied to a pieoelectric plate is excited in one direction by a standing surfactant by active IDTs with reflective structures so that the inertial masses are in its antinodes, and the total surfactant field is of a regular structure of inertial masses, consisting of SAW fields that are diffraction and signal from the Coriolis forces, are recorded in the direction perpendicular to the standing SAW by measuring IDT, while the diffraction field Surfactants measuring GSW is recorded as a non-rotating device, and during its rotation, and the signal field - only when the device is rotated.

A significant disadvantage of the prototype, hindering its practical use, is the limitation of its functionality, due to the fact that this device provides registration of the angular velocity of rotation of the carrier base relative to only one direction of rotation. To register angular velocities with respect to two directions of rotation of the bearing base, it is necessary to additionally install a second similar gyroscope on it, which leads to a complication of the structure and an increase in its cost.

The aim of creating the proposed technical solution is to expand the functionality by converting the angular speeds of rotation of the base into electrical signals simultaneously relative to two axes of rotation.

To achieve this goal, a microacoustomechanical gyroscope is proposed that contains a bearing base, a regular structure of inertial masses placed in a checkerboard pattern, active piezoelectric transducers and measuring IDTs of the total surfactant field from the regular structure of inertial masses consisting of surfactant fields that are diffractive and signal from Coriolis forces.

According to the invention, in the proposed microacoustomechanical gyroscope, the carrier base is made of isotropic material, a thin piezoelectric film is applied on the outer surface of the carrier base with a regular structure of inertial masses and measuring IDTs for each of the directions of rotation of the bearing base, while the measuring IDTs are placed symmetrically relative to the position regular structure of inertial masses and perpendicular to the axis of rotation of the bearing base, on the inner surface ti bearing base is made trapezoidal protrusion whose larger base faces the outer surface of the support base, the active piezoelectric transducers arranged symmetrically to each other on side surfaces of the trapezoidal projection and provide excitation of longitudinal acoustic waves in the material of the carrier base in a direction defined by an angle Q.

Wherein

SINQ = V _L / V _R ,

where V _L is the velocity of longitudinal waves in the material of the bearing base;

V _R - surfactant speed,

and the angle Q is defined by the position of the lateral surfaces of the trapezoidal protrusion relative to the outer surface of the carrier base.

Figure 1 schematically shows the proposed microacoustomechanical gyroscope (top view), figure 2 is a section aa.

The proposed microacoustomechanical gyroscope (Fig. 1) contains a carrier base 1 made of an isotropic material, on the outer surface 2 of which a thin film 3 of a piezoelectric with a regular structure of inertial masses 4 and measuring IDT 5, 6 (relative to the X axis) is installed on it and 7, 8 (relative to the Y axis), respectively, of the total surfactant field from the regular structure of inertial masses 4, consisting of the surfactant fields that are diffractive and signal from the Coriolis forces.

A trapezoidal protrusion 10 is made on the inner surface 9 (FIG. 2) of the bearing base 1, having a small base 11, a larger base 12 and side surfaces 13, with the larger base 12 facing the outer surface 2 of the bearing base 1.

The lateral surfaces 13 of the trapezoidal protrusion 10 form an angle Q with the outer surface 2 of the bearing base 1, which is selected from the condition of optimal excitation of the surfactant on the outer surface 2 of the bearing base 1:

SINQ = V _L / V _R ,

where V _L is the velocity of longitudinal waves in the material of the bearing base 1,

V _R - surfactant speed.

The angle Q is set by the position of the side surfaces 13 of the trapezoidal protrusion 10 relative to the outer surface 2 of the bearing base 1.

Active piezoelectric transducers 14 and 15 are mounted symmetrically to each other on the lateral surfaces 13 of the trapezoidal protrusion 10, which provide excitation of longitudinal acoustic waves in the material of the carrier base 1 in the directions determined by the angle Q.

Measuring IDTs 5, 6 (relative to the X axis) and 7, 8 (relative to the Y axis) are mounted on the film 3 symmetrically with respect to the position of the regular structure of inertial masses 4 and perpendicular to the axes of rotation of the bearing base 1.

Inertial masses in the regular structure of inertial masses 4 are placed in a checkerboard pattern with distances between them providing primary radiation in the directions to the measuring IDT 5, 6 and 7, 8.

The proposed microacoustomechanical gyroscope works as follows.

Active piezoelectric transducers 14 and 15 excite longitudinal waves in the base 1, which, when interacting with the outer surface 2 of the base 1, excite surfactants traveling in different directions along the X axis.

In the region 16 (figure 2) of the interference of longitudinal wave beams on the outer surface 2 of the bearing base 1 at the location of the regular structure of inertial masses 4, a standing wave with distances between antinodes equal to:

λ _R / 2,

where λ _R = V _R / f is the excitation frequency.

Under the influence of standing waves, the masses of the regular structure of inertial masses 4 perform vertical (along the Z axis) (not shown in Fig. 2) oscillations and, in turn, are sources of surfactants that propagate along the X and Y axes. Thus, from region 16 The interference of the longitudinal wave beams towards the measuring IDTs 5, 6 and 7, 8 propagates traveling waves, which are detected by IDT data. As a result, the corresponding signals appear at the outputs of the measuring IDTs 5, 6, and 7, 8.

During rotation of the carrier base 1 relative to the X axis, the Coriolis force directed along the Y axis acts on the masses moving along the Z axis:

F = 2m (Ω × V),

where m is the mass of the oscillating structure;

Ω is the angular velocity of rotation of the gyroscope;

V is the vibrational velocity of the mass.

Under the influence of this force, an additional surfactant is generated, which changes the electrical signals at the IDT outputs 7 and 8. This change is proportional to the angular velocity Ω directed along the X axis and is fixed by an appropriate meter (not shown). At the output of IDT 5 and 6, the signals remain virtually unchanged.

When the carrier base 1 rotates around the Y axis, similar phenomena occur, and useful signals occur at the IDT outputs 5 and 6.

With the simultaneous rotation of the carrier base 1 relative to the X and Y axes, useful signals appear on all measuring IDTs 5, 6 and 7, 8, and the signal level at the IDT outputs 7 and 8 corresponds to the rotation speed relative to the X axis, and the signal level at IDT outputs 5, 6 corresponds to the rotation speed with respect to the Y axis. Thus, useful signals are recorded that allow determining the rotation speeds of the carrier base 1 with respect to two axes of rotation.

A comparative analysis revealed that, in contrast to analog devices and a prototype device, the proposed microacoustomechanical gyroscope is characterized by new features, namely, new structural elements having a new shape and arrangement in the proposed device, which allow expanding the functionality by converting the angular rotation speeds of the bearing base into electrical signals simultaneously relative to two axes of rotation.

The proposed device, while maintaining the positive qualities of the analogues and prototype described in the description, differs in comparison with them in the expansion of functionality by converting the angular speeds of rotation of the carrier base into electrical signals simultaneously relative to two rotation axes and can be used in navigation, orientation and control systems of various mobile objects.

Claims (1)

A microacoustomechanical gyroscope containing a bearing base, a regular structure of inertial masses placed in a checkerboard pattern, active piezoelectric transducers and measuring interdigital transducers of the total field of surface acoustic waves from the regular structure of inertial masses, consisting of the fields of surface acoustic waves diffraction and signal from the Coriolis forces, characterized in that the carrier base is made of isotropic material, based on the outer surface of the carrier a thin piezoelectric film is applied with a regular structure of inertial masses mounted on it and measuring interdigital transducers for each of the directions of rotation of the bearing base, while measuring interdigital transducers are placed symmetrically with respect to the position of the regular structure of inertial masses and perpendicular to the axes of rotation of the bearing base, a trapezoidal protrusion is made on the inner surface of the bearing base, the larger base of which is turned to the sides near the outer surface of the carrier base, the active piezoelectric transducers are mounted symmetrically to each other on the lateral surfaces of the trapezoidal protrusion and provide excitation of longitudinal acoustic waves in the material of the carrier base in the directions determined by the angle Q, while
SIN Q = V _L / V _R ,
where V _L is the velocity of longitudinal waves in the material of the bearing base;
V _R is the speed of the surface acoustic wave;
and the angle Q is defined by the position of the lateral surfaces of the trapezoidal protrusion relative to the outer surface of the carrier base.

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