RU2810721C1 - Device for measuring tilt angle - Google Patents

Abstract

FIELD: measuring instrumentation.

SUBSTANCE: invention relates to inclinometers, and can be used to record fluctuations in the angular position of the Earth's surface in order to study microseismic phenomena. The device contains a base, a single-mode stabilized laser source, a cuvette with a viscous dielectric liquid, a recording device made in the form of an interferometric device consisting of an optical wedge-shaped plate, an optical device that deflects the path of the laser beam, made in the form of an optical cube, and a photodetector with a recording unit. Also, to adjust the interferometric device, an angular positioner is used, which contains a movable platform, an adjustment screw and a ball joint. The beam from a single-mode laser source is perpendicular to the surface of the liquid. The use of an interferometric device as a recording device makes it possible to make the registration of the angular inclination of the base insensitive to the angular inclination of the laser beam from a single-mode laser source.

EFFECT: increase in the accuracy of measuring changes in the angular position of the base.

2 cl, 4 dwg

Description

The invention relates to control and measuring equipment, namely, to inclinometers.

It can be used to record fluctuations in the angular position of the Earth's surface in order to study microseismic phenomena, both in the high-frequency region of the spectrum to study earthquakes, and in the low-frequency region of the spectrum to study the slow changes in the landscape of the Earth's surface in order to predict earthquakes.

There are several devices for recording the angular inclination of the Earth's surface relative to the Earth's gravity vector. Known: Patent SU 1194125, “Device for measuring the angle of inclination of an object”, Khlobystov A.V.; RF Patent 2093791, “Sensor for angle of deviation from the vertical”, Oryol State Technical University, Esipov, V. N.; RF Patent 2107896, “Liquid optical level”, Peoples' Friendship University of Russia, Nikitin A.K.; RF Patent No. 2510488, “Device for measuring the angle of inclination”, Joint Institute for Nuclear Research, Budagov Yu.A., Lyablin M.V.

Analogs use a horizontal liquid surface and reflection of a laser or ultrasonic beam from it. Determination of the angular change of the base relative to the vertical position of the gravity vector occurs using a system of photodetectors and ultrasound sensors. The disadvantage of these analogues is the low accuracy of measuring the angles of inclination of the Earth's surface.

The prototype of the invention is RF Patent No. 2510488 “Device for measuring the angle of inclination”, Joint Institute for Nuclear Research, Budagov Yu.A. Lyablin M.V., IPC G01C1/10.

The invention contains a base on which are fixed: an optical single-mode stabilized laser source, a cuvette with a viscous dielectric liquid, a position-sensitive photodetector device (PSPD); and a registration block. When the base is tilted, the laser beam reflected from the surface of a viscous dielectric liquid changes its angular position, which is recorded by the PCFU. In this case, the device uses a thin layer of viscous dielectric liquid in a cuvette with a ratio of the thickness of the liquid layer in the cuvette to its diameter in the range from 0.04 to 0.06 to reduce unwanted surface distortions.

In the cited devices and the prototype, there is noise in the angular displacement of the beam from a single-mode stabilized laser source, caused by changes in the deformation of the laser cavity during thermal exchange between the laser active zone and the environment. In this case, noise angular mixing of the laser beam occurs, which is recorded as a signal in the PFNC. This type of noise significantly reduces the sensitivity of the inclinometer.

The invention is aimed at eliminating the disadvantage present in analogues and the prototype. Reducing the angular mixing noise of the laser beam in the signal structure will lead to an increase in the sensitivity of recording angular vibrations of the base.

The proposed invention solves the problem of increasing the accuracy of measuring the angular position of the base by reducing the influence of the angular displacement noise of the beam from a single-mode laser source caused by changes in the deformation of the laser cavity during thermal exchange between the laser active zone and the environment.

The solution to the problem is achieved by the fact that the device for measuring the angle of inclination contains: a base, a single-mode stabilized laser source, a cuvette with a viscous dielectric liquid, with a ratio of the thickness of the liquid layer in the cuvette to its diameter in the range from 0.04 to 0.06, and a recording device.

The surface of the viscous dielectric liquid is located in the path of the laser beam, and the path of the laser beam perpendicular to the surface of the viscous dielectric liquid is used; the recording device is an interferometric device consisting of an optical wedge-shaped plate, one of the planes of which is located parallel to the surface of a viscous dielectric liquid, an optical laser beam that deflects the path of motion, a device and a photodetector with a recording unit; an angular positioner is additionally introduced, which serves to adjust the interferometric device, which consists of a movable platform, an adjustment screw and a ball joint; in this case, the laser source, the cuvette with a viscous dielectric liquid and the interferometric device are rigidly fixed on the movable platform, the optical wedge-shaped plate and the optical device that deflects the path of the laser beam are located on the path of the laser beam, and the optical device that deflects the path of the laser beam serves for outputting interfering laser beams reflected from the surface of a viscous dielectric liquid and the surface of an optical wedge-shaped plate parallel to the surface of a viscous dielectric liquid to a photodetector. An optical device that deflects the path of the laser beam is made in the form of an optical dividing cube.

Distinctive features of the proposed invention are:

• Perpendicular, relative to the surface of the viscous dielectric liquid, direction of movement of the laser beam;

• to record changes in the angular position of a laser beam reflected from the surface of a viscous dielectric liquid, an interferometric device is used,

• interferometric device, consists of a laser beam deflecting device, an optical wedge-shaped plate of a photodetector and a recording unit, while the optical wedge-shaped plate is located along the path of the laser beam and one of its planes is parallel to the surface of the viscous dielectric liquid,

• An optical device that deflects the laser beam is located in the path of the laser beam,

• an angular positioner, used to adjust the interferometric device, is located on the base and includes: a movable platform, a quotation screw and a ball joint,

• single-mode stabilized laser source, a cell with a viscous dielectric liquid and an interferometric device are rigidly mounted on a moving platform,

• optical, deflecting the path of the laser beam, the device is made in the form of an optical dividing cube.

The combination of the above features makes it possible to achieve the goal, namely, increasing the accuracy of measuring the angular position of the base by reducing the influence of the noise of the angular displacement of the laser beam from a single-mode stabilized laser source.

When there is a noise change in the angular direction of the laser beam from a single-mode stabilized laser source, there is no change in the interfering beams, since simultaneously both the laser beam reflected from the inclined plate and the laser beam from the surface of the liquid are tilted by the angle of change in the direction of the beam from the laser source.

List of illustrations.

In FIG. 1 Appendix 1 presents the elements of a device for measuring the angle of inclination with an optical deflection device made in the form of an optical dividing cube.

In FIG. 2 Appendix 1 shows a diagram of the passage of laser beams in the inclinometer while measuring the angle of inclination of the base.

In FIG. 3. Appendix 2. presents a diagram of the passage of laser beams in the inclinometer when changing the inclination of the base

In FIG. 4. Appendix 2 shows a diagram of the passage of laser beams in the inclinometer when changing the angular direction of the laser beam from a single-mode stabilized laser source.

In FIG. 1 Appendix 1 contains elements where:

1. base,

2. movable platform,

3. quotation screw,

4. ball joint,

5. single mode stabilized laser source,

6. cuvette with a viscous dielectric liquid,

7. a layer of liquid in a cuvette with a thickness to its diameter ranging from 0.04 to 0.06,

8. optical wedge plate,

9. optical, deflecting the path of the laser beam, a device made in the form of an optical cube,

10. photodetector,

11. registration block.

In FIG. 2 Appendix 1 shows the elements of the inclinometer and the path of laser beams

1. base,

2. movable platform,

3. quotation screw,

4. ball joint,

5. single-mode stabilized laser source,

6. cuvette with a viscous dielectric liquid,

7. a layer of liquid in a cuvette with a thickness to its diameter ranging from 0.04 to 0.06,

8. optical wedge plate,

9. optical, deflecting the path of the laser beam, a device made in the form of an optical cube,

10. photodetector,

11. registration block,

12. path of movement of the laser beam from a single-mode stabilized laser source,

13. surface of a viscous dielectric liquid,

14. path of movement of the laser beam reflected from the surface of the optical wedge-shaped plate,

15. path of movement of the laser beam reflected from the surface of a viscous dielectric liquid,

16. path of movement of interfering laser beams,

17. direction of movement of the moving platform,

In FIG. 3 Appendix 2 shows the elements of the inclinometer and the paths of laser beams. The dashed lines correspond to the inclinometer elements and the paths of laser beams when the base is tilted. Solid lines - no slope.

5. single-mode stabilized laser source,

6. cuvette with a viscous dielectric liquid,

8. optical wedge plate,

12. path of movement of the laser beam from a single-mode stabilized laser source,

13. surface of a viscous dielectric liquid,

14. path of movement of the laser beam reflected from the surface of the optical wedge-shaped plate

15. path of movement of a laser beam reflected from the surface of a viscous dielectric liquid

18. angle between laser beams reflected from the optical wedge-shaped plate and from the surface of the liquid.

In FIG. Figure 4 shows the elements and paths of movement of laser beams. The dashed lines of the paths of laser beams correspond to the position when the laser beam is tilted from a single-mode stabilized laser stoker.

5. single-mode stabilized laser source,

6. cuvette with a viscous dielectric liquid,

8. optical wedge plate,

12. path of movement of the laser beam from a single-mode stabilized laser source,

13. surface of a viscous dielectric liquid,

14. path of movement of the laser beam reflected from the surface of the optical wedge-shaped plate,

15. path of movement of a laser beam reflected from the surface of a viscous dielectric liquid.

The device shown in Fig. 2 Appendix 1 contains a base (1) on which are rigidly fixed: an angular positioner, consisting of a movable platform (2), an adjusting screw (3) and a ball joint (4). A single-mode stabilized laser source (5), a cuvette with a viscous dielectric liquid (6), a layer of liquid in the cuvette with a thickness to its diameter ranging from 0.04 to 0.06 (7), an optical wedge-shaped plate (8), are fixed on the movable platform (2). optical, deflecting the path of the laser beam, a device made in the form of an optical cube (9), photodetector (Y), registration unit (11).

The operation of the device is illustrated in Fig. 2 Appendix 1 A single-mode stabilized laser source (5) is installed so that its beam (12) is perpendicular to the surface of the viscous dielectric liquid (13).

The laser beam (12) passes through the optical dividing cube (9) and the optical wedge plate (8). Then it occurs sequentially: reflection of the laser beam (12) from the surface of the optical wedge-shaped plate (8) and from the surface of the viscous dielectric liquid (13). The reflected laser beam (14) from the plane of the optical wedge-shaped plate (8), which is parallel to the surface of the viscous dielectric liquid (13), and the reflected laser beam (15) from the surface of the liquid (13) coincide and interfere with each other. Using an optical dividing cube (9), interfering laser beams (16) are positioned on a photodetector (10) with a registration unit (11).

Using an angular positioner, which includes a movable platform (2), an adjustment screw (3) and a ball joint (4), the interfering laser beams (16) are adjusted (17). When the angle of inclination of the movable platform (2) is changed by the adjustment screw (3), the angle of inclination of the optical wedge-shaped plate (8) changes relative to the surface of the viscous dielectric liquid. By selecting the required angle of inclination of the movable platform (2), the plane of the optical wedge-shaped plate is set in a parallel position with the surface of the viscous dielectric liquid (13). When the base (1) is tilted, the intensity of laser radiation in the interfering beams (16) changes proportional to the tilt angle of the base (1). The change in laser radiation intensity, which is proportional to the angle of inclination of the base, is received by a photodetector (10) with a registration unit (11).

The directions of laser beams in the inclinometer when the base is tilted are shown in Fig. 3 Appendix 2.

The independence of the inclinometer readings from the angle of inclination of the laser beam is demonstrated by the direction of the laser beams before and after the inclination of the base Fig. 3 Appendix 2.

Solid lines show the elements of the inclinometer and the direction of the laser beams before the base is tilted, and the dashed lines show after the base is tilted.

After tilting the base (1) (Fig. 2 Appendix 1), the inclinometer elements are tilted, namely, cuvettes with a viscous dielectric liquid (b), an optical wedge-shaped plate (8), a single-mode stabilized laser source (5) (shown with a dashed line). Due to the horizontal surface of the liquid, an angular divergence (18) occurs between the laser beams (14, 12) reflected from the surface of the optical wedge-shaped plate (8) and from the surface of the liquid (13). Angular divergence (18) - the angle between laser beams reflected from the optical wedge-shaped plate and from the surface of the liquid. The resulting angle (18) between the laser beams (14, 12), reflected from the surface of the optical wedge-shaped plate (8) and from the surface of the liquid (13), changes the intensity of the interfering laser beams (16) (Fig. 2 Appendix 1). The change in the intensity of the interfering laser beams (16) (Fig. 2 Appendix 1) is subsequently received by the photodetector (8) with the registration unit (11).

The path of the laser beams after tilting the laser beam is shown in FIG. 4 Appendix 2.

The independence of the inclinometer readings from the influence of the noise of the angular displacement of the beam from a single-mode laser source (5) is ensured by the fact that the noise tilt of the laser beam occurs simultaneously, both in the laser beam (15) reflected from the surface of the viscous dielectric liquid (13), and in the laser beam reflected from the surface optical wedge-shaped plate (8) with a laser beam (14), while the parallelism of these laser beams does not change. Therefore, beam angular displacement noise from a single-mode laser source does not change the parallelism of the interfering beams (16) (Fig. 2 Appendix 1) and, therefore, does not change their intensity. Ultimately, the inclinometer readings become independent of the influence of beam angular displacement noise from a single-mode laser source (5).

An example of a specific implementation.

As:

- single-mode laser source, a single-mode semiconductor laser can be used with laser radiation output through a single-mode optical fiber,

- vacuum oil is applicable for viscous dielectric liquid,

- a silicon photodiode can be used for the photodetector,

- registration unit - amplitude-to-digital converter and computer.

Wedge-shaped optical plate and optical dividing cube are produced by optical companies and are available to consumers.

In addition, the optical deflection device can be made in the form of a plane-parallel dividing plate. This optical element is mass-produced by optical companies. In the absence of an optical dividing cube, the optical deflection device can be made in the form of a plane-parallel dividing plate.

The cuvette, fastening of inclinometer elements, movable platform, adjustment device, ball joint were produced as a prototype in mechanical production at the Joint Institute for Nuclear Research.

The use of the invention makes it possible to reduce the influence of noise in the angular displacement of a laser beam from a single-mode laser source by more than 10 times, which increases the final accuracy of measuring the inclination angle.

Claims (2)

1. A device for measuring the inclination angle, including a base, a single-mode stabilized laser source, a cuvette with a viscous dielectric liquid with a ratio of the thickness of the liquid layer in the cuvette to its diameter in the range from 0.04 to 0.06, and the surface of the viscous dielectric liquid is located in the path of the laser beam and a recording device, characterized in that the path of movement of the laser beam is used perpendicular to the surface of the viscous dielectric liquid; the recording device is an interferometric device consisting of an optical wedge-shaped plate, one of the planes of which is located parallel to the surface of a viscous dielectric liquid; an optical device and a photodetector with a recording unit have been introduced to deflect the path of the laser beam; an angular positioner is additionally introduced, which serves to adjust the interferometric device, which consists of a movable platform, an adjustment screw and a ball joint; in this case, a single-mode stabilized laser source, a cell with a viscous dielectric liquid and an interferometric device are rigidly fixed on a movable platform; an optical wedge-shaped plate and an optical device deflecting the path of movement of the laser beam are located on the path of movement of the laser beam, and an optical deflecting device of the path of movement of the laser beam is used to output interfering laser beams reflected from the surface of the viscous dielectric liquid and the surface of the optical wedge-shaped plate parallel to the surface of the viscous dielectric liquid, to the photodetector. 2. The device according to claim 1, characterized in that the optical device that deflects the path of the laser beam is made in the form of an optical dividing cube.