1. A flexible pendulum piece displacement testing device is used for testing the displacement of a flexible pendulum piece of a quartz accelerometer influenced by temperature, the flexible pendulum piece comprises a pendulum tongue and a coil arranged on the pendulum tongue, and a gold-plated film layer covers part of the surface of the pendulum tongue to form a reflecting area, and the flexible pendulum piece displacement testing device is characterized by comprising a light source, a light splitting plate, a temperature regulator, a first reflector set and a photoelectric detector, wherein parallel light emitted by the light source is reflected and transmitted at the light splitting plate to respectively form first detection light and second detection light, the first detection light is reflected to the first reflector set through the light splitting plate, passes through the light splitting plate again after being reflected by the first reflector set, is transmitted by the light splitting plate and then is received by the photoelectric detector, and the second detection light is transmitted to the reflecting area through the light splitting plate, the temperature regulator is used for regulating the temperature of the coil and acquiring the first displacement of the flexible pendulum piece at a set temperature according to the optical path information received by the photoelectric detector.

2. The apparatus according to claim 1, wherein the area of the pendulum tongue not covered by the gold-plated thin film is a transmissive area, the apparatus further comprises a second mirror set, the parallel light emitted from the light source is reflected and transmitted by the beam splitter to form a third detection light and a fourth detection light, respectively, the third detection light is reflected by the beam splitter to the first mirror set, reflected by the first mirror set, passes through the beam splitter again, and is received by the photodetector after being transmitted by the beam splitter, the fourth detection light is transmitted by the beam splitter to the transmissive area, transmitted by the transmissive area to the second mirror set, reflected by the second mirror set to the transmissive area, transmitted by the transmissive area to the beam splitter, and reflected by the beam splitter to be received by the photodetector, and acquiring a thermal expansion error of the flexible pendulous reed at a set temperature according to optical path information received by the photoelectric detector, and acquiring a second displacement of the flexible pendulous reed according to the first displacement of the flexible pendulous reed and the thermal expansion error.

3. The flexure pendulum displacement test apparatus of claim 1, further comprising a collection mirror, wherein the first detection light and the second detection light are collected by the collection mirror and received by the photodetector.

4. The flexible pendulum piece displacement testing device of claim 1, wherein the flexible pendulum piece further comprises a flexible beam and an outer ring, the coil is fixed on the pendulum tongue, the outer ring is disposed around the pendulum tongue, the pendulum tongue is connected with the outer ring through the flexible beam, and the pendulum tongue can swing relative to the outer ring, the flexible pendulum piece displacement testing device further comprises two identical fixtures, each fixture comprises a movable fixing base, a height-adjustable supporting frame and a hollow ring, the supporting frame is connected with the fixing base and the hollow ring, and the outer ring is clamped between the hollow rings of the two fixtures.

5. A flexible pendulous reed displacement testing method, characterized in that the displacement of a flexible pendulous reed of a quartz accelerometer influenced by temperature is tested by using the flexible pendulous reed displacement testing device according to any one of claims 1-4, and the method comprises the following steps:

s1, adjusting the positions of the beam splitter, the first reflector group, the flexible swinging sheet and the photoelectric detector;

step S2, setting the temperature of the coil of the flexible pendulous reed through a temperature regulator;

step S3, the light source is started, so that parallel light emitted by the light source is reflected and transmitted by the beam splitter to form first detection light and second detection light respectively, the first detection light is reflected to the first reflector group by the beam splitter, reflected by the first reflector group, passes through the beam splitter again, is transmitted by the beam splitter, and is received by the photodetector, the second detection light is transmitted to the reflection area of the flexible pendulum piece by the beam splitter, reflected by the reflection area, passes through the beam splitter again, reflected by the beam splitter, and is received by the photodetector, and a first displacement of the flexible pendulum piece at a set temperature is obtained according to optical path information received by the photodetector.

6. The flexible pendulous reed displacement testing method of claim 5, further comprising a second mirror group, wherein after the step S2 is performed and before the step S3 is performed, the flexible pendulous reed displacement testing method further comprises:

the light source is started, parallel light emitted by the light source is reflected and transmitted at the light splitting plate to form third detection light and fourth detection light respectively, the third detection light is reflected to the first reflector group through the light splitting plate, reflected by the first reflector group, passes through the light splitting plate again, is transmitted by the light splitting plate and then is received by the photoelectric detector, the fourth detection light is transmitted to the transmission area through the light splitting plate, is transmitted to the second reflector group through the transmission area, is reflected to the transmission area through the second reflector group, is transmitted to the light splitting plate through the transmission area, is reflected by the light splitting plate and then is received by the photoelectric detector, and thermal expansion error of the flexible pendulum piece at the set temperature is obtained according to light path information received by the photoelectric detector.

7. The flexible pendulum displacement test method of claim 6, wherein after the step S3, the flexible pendulum displacement test method further comprises:

and step S4, obtaining a second displacement of the flexible pendulous reed according to the first displacement of the flexible pendulous reed and the thermal expansion error.

8. The flexible pendulum displacement testing method of claim 7, wherein after the step S4, the flexible pendulum displacement testing method further comprises:

s5, adjusting the position of the flexible swing piece to enable the second detection light to be emitted on test points at different positions of the reflection area, wherein the vertical distances from the test points to the fixed end of the swing tongue are different;

s6, repeating the steps S3-S4 to obtain second displacements corresponding to different test points;

and S7, performing least square fitting on the data of the second displacements corresponding to all the test points to obtain a third displacement of the flexible pendulous reed.

9. The flexible pendulum displacement test method of claim 8, further comprising:

and adjusting the temperature of the coil of the flexible pendulous reed through a temperature adjuster, and repeating the steps to obtain third displacement of the flexible pendulous reed at different coil temperatures.

10. The flexible pendulum piece displacement test method of claim 6, wherein the first displacement and thermal expansion error of the flexible pendulum piece at the set temperature are calculated by the following formula:

Δh＝Nλ/2

wherein Δ h is a first displacement or thermal expansion error of the flexible pendulous reed at the set temperature, N is the number of field center movement fringes in the photodetector, and λ is the wavelength of the parallel light emitted by the light source.

Background

The accelerometer plays a crucial role in the rapid development of inertial navigation systems, and its basic function is to measure the linear acceleration in a direction, which the accelerometer will produce the largest output signal when an acceleration force acts in or around this direction. The accelerometer is widely applied to the fields of petroleum, ships, automobiles and the like, and the quality of the function of the accelerometer plays an irreplaceable role in inertial navigation.

The quartz flexible accelerometer has wide application scenes, the working principle of the quartz flexible accelerometer is that a flexible pendulous reed and a coil form a detection mass block, the detection mass block can displace relative to a balance position under the action of inertia, so that inertia moment is generated, the capacitance is changed due to the change of the distance between differential capacitors, corresponding current signals are output by detecting the change through a servo circuit, and the current signals are fed to a torquer to generate feedback moment so that the pendulous reed returns to the balance position. Because the displacement of the pendulous reed is directly related to the output of the accelerometer, the electrification of the coil can generate certain temperature change. Therefore, it is of great significance to study the displacement of the flexible pendulum piece when the flexible pendulum piece is affected by temperature.

The flexible pendulous reed of the quartz flexible accelerometer generally consists of quartz glass, a gold-plated film layer and a torque coil, the output of the accelerometer generally adopts a capacitance detection method, and because the displacement generated by the flexible pendulous reed is very small, the capacitance change of the flexible pendulous reed is also very small, the precision and the sensitivity of the capacitance detection method are difficult to improve. The changes of the capacitance value and the influence of the temperature change of the coil are mutually coupled, so that the output error of the accelerometer is difficult to separate.

Disclosure of Invention

The invention aims to provide a flexible pendulous reed displacement testing device and a testing method, which solve the problems of low resolution, high noise, low precision and slow response time caused by time integration in the traditional capacitance type detection method and improve the output precision of a quartz accelerometer.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a flexible pendulum piece displacement testing apparatus for testing displacement of a flexible pendulum piece of a quartz accelerometer affected by temperature, the flexible pendulum piece including a pendulum tongue and a coil disposed on the pendulum tongue, a part of a surface of the pendulum tongue being covered with a gold-plated film layer to form a reflection area, the flexible pendulum piece displacement testing apparatus including a light source, a beam splitter, a temperature regulator, a first mirror group and a photodetector, parallel light emitted from the light source being reflected and transmitted at the beam splitter to form a first detection light and a second detection light, respectively, the first detection light being reflected by the beam splitter to the first reflection light, reflected by the first mirror group to pass through the beam splitter again, transmitted by the beam splitter to be received by the photodetector, and the second detection light being transmitted to the reflection area through the beam splitter, the temperature regulator is used for regulating the temperature of the coil and acquiring the first displacement of the flexible pendulum piece at a set temperature according to the optical path information received by the photoelectric detector.

Optionally, an area of the pendulum tongue not covered by the gold-plated thin film is a transmission area, the flexible pendulum displacement testing apparatus further includes a second mirror group, parallel light emitted by the light source is reflected and transmitted at the beam splitter to form third detection light and fourth detection light, respectively, the third detection light is reflected by the beam splitter to the first mirror group, reflected by the first mirror group, passes through the beam splitter again, is transmitted by the beam splitter, and is received by the photodetector, the fourth detection light is transmitted to the transmission area through the beam splitter, is transmitted to the second mirror group through the transmission area, is reflected to the transmission area through the second mirror group, is transmitted to the beam splitter through the transmission area, is reflected by the beam splitter, and is received by the photodetector, and a thermal expansion error of the flexible pendulum piece at a set temperature is obtained according to optical path information received by the photodetector, and obtaining a second displacement of the flexible pendulous reed according to the first displacement of the flexible pendulous reed and the thermal expansion error.

Optionally, the flexible pendulum piece displacement testing device further includes a converging mirror group, and the first detection light and the second detection light are received by the photodetector after being converged by the converging mirror group.

Optionally, the flexible pendulum piece further includes a flexible beam and an outer ring, the coil is fixed on the pendulum tongue, the outer ring is disposed around the pendulum tongue, the pendulum tongue is connected to the outer ring through the flexible beam, and the pendulum tongue can swing relative to the outer ring, the flexible pendulum piece displacement testing apparatus further includes two identical fixtures, each fixture includes a movable fixing base, a height-adjustable support frame and a hollow ring, the support frame is connected to the fixing base and the hollow ring, and the outer ring is clamped between the hollow rings of the two fixtures.

In order to achieve the above object, according to a second aspect of the present invention, there is provided a flexible pendulous reed displacement testing method for testing the displacement of a flexible pendulous reed of a quartz accelerometer affected by temperature, including the following steps:

s1, adjusting the positions of the beam splitter, the first reflector group, the flexible swinging sheet and the photoelectric detector;

step S2, setting the temperature of the coil of the flexible pendulous reed through a temperature regulator;

step S3, the light source is started, so that parallel light emitted by the light source is reflected and transmitted by the beam splitter to form first detection light and second detection light respectively, the first detection light is reflected to the first reflector group by the beam splitter, reflected by the first reflector group, passes through the beam splitter again, is transmitted by the beam splitter, and is received by the photodetector, the second detection light is transmitted to the reflection area of the flexible pendulum piece by the beam splitter, reflected by the reflection area, passes through the beam splitter again, reflected by the beam splitter, and is received by the photodetector, and a first displacement of the flexible pendulum piece at a set temperature is obtained according to optical path information received by the photodetector.

Optionally, the flexible pendulous reed displacement testing apparatus further includes a second mirror group, and after the step S2 is executed and before the step S3 is executed, the flexible pendulous reed displacement testing method further includes:

the light source is started, parallel light emitted by the light source is reflected and transmitted at the light splitting plate to form third detection light and fourth detection light respectively, the third detection light is reflected to the first reflector group through the light splitting plate, reflected by the first reflector group, passes through the light splitting plate again, is transmitted by the light splitting plate and then is received by the photoelectric detector, the fourth detection light is transmitted to the transmission area through the light splitting plate, is transmitted to the second reflector group through the transmission area, is reflected to the transmission area through the second reflector group, is transmitted to the light splitting plate through the transmission area, is reflected by the light splitting plate and then is received by the photoelectric detector, and thermal expansion error of the flexible pendulum piece at the set temperature is obtained according to light path information received by the photoelectric detector.

Optionally, after the step S3 is executed, the flexible pendulum piece displacement testing method further includes:

and step S4, obtaining a second displacement of the flexible pendulous reed according to the first displacement of the flexible pendulous reed and the thermal expansion error.

Optionally, after the step S4 is executed, the flexible pendulum piece displacement testing method further includes:

s5, adjusting the position of the flexible swing piece to enable the second detection light to be emitted on test points at different positions of the reflection area, wherein the vertical distances from the test points to the fixed end of the swing tongue are different;

s6, repeating the steps S3-S4 to obtain second displacements corresponding to different test points;

and S7, performing least square fitting on the data of the second displacements corresponding to all the test points to obtain a third displacement of the flexible pendulous reed.

Optionally, the flexible pendulum piece displacement testing method further includes:

and adjusting the temperature of the coil of the flexible pendulous reed through a temperature adjuster, and repeating the steps to obtain the first displacement or the third displacement of the flexible pendulous reed at different coil temperatures.

Optionally, the calculation formula of the first displacement and the thermal expansion error of the flexible pendulous reed at the set temperature is as follows:

Δh＝Nλ/2

wherein Δ h is a first displacement or thermal expansion error of the flexible pendulous reed at the set temperature, N is the number of field center movement fringes in the photodetector, and λ is the wavelength of the parallel light emitted by the light source.

The invention provides a displacement testing device and a displacement testing method for a flexible pendulous reed, which are used for measuring the tiny displacement of the flexible pendulous reed of a quartz accelerometer, which is influenced by temperature, by simulating the temperature change of a coil and adopting an optical phase measurement method, and solve the problems of low resolution, large noise, low precision and slow response time caused by time integration in the traditional capacitance detection method, thereby improving the output precision of the quartz accelerometer.

Drawings

It will be appreciated by those skilled in the art that the drawings are provided for a better understanding of the invention and do not constitute any limitation to the scope of the invention. Wherein:

fig. 1 is a schematic view of a displacement testing device for a flexible pendulum plate according to an embodiment of the present invention;

FIG. 2 is a schematic view of a flexible pendulum plate according to an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating a thermal expansion error test according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a distribution of test points provided by an embodiment of the present invention;

in the drawings:

1-a flexible pendulum piece; 2-a light source; 3-a light splitting plate; 4-a first set of mirrors; 5-a photodetector; 6-a converging lens group; 7-a second mirror group; 8-a holder;

10-swinging the tongue; 11-a coil; 12-a flexible beam; 13-the outer ring; 21-he-ne laser; 22-a beam expander set; 81-fixed base; 82-a support frame; 83-hollow circular ring;

100-a reflective region; 110-a transmissive region; 200-test points.

Detailed Description

As described in the background art, the flexible pendulous reed of the quartz flexible accelerometer generally consists of quartz glass, a gold-plated film layer and a torque coil, the output of the accelerometer generally adopts a capacitive detection method, and because the displacement generated by the flexible pendulous reed is very small, the capacitance change of the flexible pendulous reed is also very small, the precision and the sensitivity of the capacitive detection method are difficult to improve. The changes of the capacitance value and the influence of the temperature change of the coil are mutually coupled, so that the output error of the accelerometer is difficult to separate.

In order to solve the above problems, a core idea of the present application is to provide a displacement testing apparatus and a testing method for a flexible pendulous reed of a quartz accelerometer, the displacement testing apparatus and the testing method being used for testing the displacement of the flexible pendulous reed affected by temperature, the flexible pendulous reed comprises a pendulous reed and a coil arranged on the pendulous reed, and a part of the surface of the pendulous reed is covered with a gold-plated film layer to form a reflection area.

The flexible pendulum piece displacement testing device comprises a light source, a light splitting plate, a temperature regulator, a first reflector group and a photoelectric detector, the parallel light emitted by the light source is reflected and transmitted at the light splitting plate to form a first detection light and a second detection light respectively, the first detection light is reflected to the first reflector group by the beam splitter, reflected by the first reflector group, passes through the beam splitter again, is transmitted by the beam splitter and is received by the photoelectric detector, the second detection light is transmitted to the reflecting area through the light splitting plate, reflected by the reflecting area, passes through the light splitting plate again, reflected by the light splitting plate and received by the photoelectric detector, the temperature regulator is used for regulating the temperature of the coil, and acquiring the first displacement of the flexible pendulous reed at the set temperature according to the optical path information received by the photoelectric detector.

The flexible pendulous reed displacement testing method for testing the displacement of the flexible pendulous reed of the quartz accelerometer, which is influenced by the temperature, by utilizing the flexible pendulous reed displacement testing device comprises the following steps of:

s1, adjusting the positions of the beam splitter, the first reflector group, the flexible swinging sheet and the photoelectric detector;

step S2, setting the temperature of the coil of the flexible pendulous reed through a temperature regulator;

step S3, the light source is started, so that parallel light emitted by the light source is reflected and transmitted by the beam splitter to form first detection light and second detection light respectively, the first detection light is reflected to the first reflector group by the beam splitter, reflected by the first reflector group, passes through the beam splitter again, is transmitted by the beam splitter, and is received by the photodetector, the second detection light is transmitted to the reflection area of the flexible pendulum piece by the beam splitter, reflected by the reflection area, passes through the beam splitter again, reflected by the beam splitter, and is received by the photodetector, and a first displacement of the flexible pendulum piece at a set temperature is obtained according to optical path information received by the photodetector.

The method is based on the optical interference principle, and considers that a part of the surface of the pendulum tongue is covered with a gold-plated film layer, the gold-plated film layer has good light reflecting performance and can be equivalent to a reflector, then the micro displacement of the flexible pendulum piece of the quartz accelerometer, which is influenced by temperature, is measured by an optical phase measurement method through simulating the temperature change of the coil, so that the problems of low resolution, high noise, low precision and slow response time caused by time integration in the traditional capacitance detection method are solved, and the output precision of the quartz accelerometer is improved.

To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is to be noted that the drawings are in greatly simplified form and are not to scale, but are merely intended to facilitate and clarify the explanation of the embodiments of the present invention. Further, the structures illustrated in the drawings are often part of actual structures. In particular, the drawings may have different emphasis points and may sometimes be scaled differently.

As used in this application, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this disclosure, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise. As used in this disclosure, the term "plurality" is generally employed in its sense including "at least one" unless the content clearly dictates otherwise. As used in this disclosure, the term "at least two" is generally employed in a sense including "two or more" unless the content clearly dictates otherwise. Furthermore, the terms "first", "second", "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", "third" may explicitly or implicitly include one or at least two of the features.

As shown in fig. 1-2, fig. 1 is a schematic view of a flexible pendulum piece displacement testing apparatus provided in an embodiment of the present invention, and fig. 2 is a schematic view of a flexible pendulum piece provided in an embodiment of the present invention. The embodiment provides a displacement testing device for a flexible pendulum piece, which is used for testing the displacement of a flexible pendulum piece 1 of a quartz accelerometer affected by temperature, wherein the flexible pendulum piece 1 comprises a pendulum tongue 10 and a coil 11 arranged on the pendulum tongue 10, a part of the surface of the pendulum tongue 10 is covered with a gold-plated film layer to form a reflection area 100, the displacement testing device for the flexible pendulum piece comprises a light source 2, a beam splitter 3, a temperature regulator, a first reflector group 4 and a photodetector 5, parallel light emitted by the light source 2 is reflected and transmitted at the beam splitter 3 to respectively form first detection light and second detection light, the first detection light is reflected to the first reflector group 4 through the beam splitter 3, passes through the beam splitter 3 again after being reflected by the first reflector group 4, and is received by the photodetector 5 after being transmitted by the beam splitter 3, and the second detection light is transmitted to the reflection area 100 through the beam splitter 3, the temperature regulator is used for regulating the temperature of the coil 11, and acquiring the first displacement of the flexible pendulum piece 1 at a set temperature according to the optical path information received by the photoelectric detector 5.

Specifically, referring to fig. 2, the flexible pendulum plate 1 generally includes a pendulum tongue 10, a coil 11, a flexible beam 12 and an outer ring 13, the pendulum tongue 10 is generally made of quartz glass, the coil 11 is fixed on the pendulum tongue 10, the outer ring 13 is disposed around the pendulum tongue 10, the pendulum tongue 10 is connected to the outer ring 13 through the flexible beam 12, and when the coil 11 is powered on (i.e., when a temperature occurs), the pendulum tongue 10 is caused to swing relative to the outer ring 13, i.e., a small displacement is generated, so that the present application substantially tests a small displacement of the pendulum tongue 10 for a displacement test of the flexible pendulum plate 1.

When the temperature of the coil 11 changes, the flexible pendulum piece 1 generates a small displacement, the first detection light and the second detection light converge with different optical paths to generate interference, and interference fringes are formed and detected by the optical photodetector 5, so that the displacement of the flexible pendulum piece 1 affected by the temperature can be calculated according to the optical path change observed in the photodetector 5. For example, when the light path distance of the second detection light is reduced by the minute displacement of the flexible pendulum piece 1, if a stripe of equal thickness is observed, the stripe moves in the direction of the thicker film; if isocline fringes are observed, the fringes shrink towards the center. The small displacement of the flexible pendulum 1 is λ/2 for each movement of one stripe. Therefore, the displacement of the flexible pendulous reed 1 of the quartz accelerometer influenced by temperature can be related to the wavelength lambda of parallel light by using optical phase detection, and the expression is as follows:

Δh₁＝Nλ/2

wherein,. DELTA.h₁For the first displacement of the flexible pendulous reed 1 at the set temperature, N is the number of field center shift stripes in the photoelectric detector 5, and λ is the wavelength of the parallel light emitted by the light source 2.

In this embodiment, the light source 2 may be a he-ne laser 21, and the laser emitted by the he-ne laser 21 has better monochromaticity, high directivity, coherence and high brightness compared with the ordinary light source 2, the laser emitted by the he-ne laser 21 has a certain divergence angle, and can obtain parallel monochromatic light, i.e. parallel light, by matching with the beam expander set 22, and the wavelength of the he-ne laser 21 is known, for example, 632.8 nm.

The temperature regulator is used for regulating the temperature of the coil 11 and simulating the temperature change generated by electrifying the coil 11 when the quartz accelerometer measures the acceleration so as to test the displacement of the flexible pendulum piece 1 influenced by the temperature, the temperature regulator is an incubator for example, and the flexible pendulum piece 1 is placed in the incubator. Of course, the temperature regulator may also adopt other devices capable of regulating the temperature change of the coil 11, such as a device for electrifying the coil 11.

The light splitting plate 3 belongs to a reflecting prism, is a composite prism, and is formed by gluing a right-angle tombstone coated with a neutral light splitting film and another right-angle prism with the same size, so that one beam of light can be split into two beams of light with any light intensity ratio. The beam splitter used by us can reflect and transmit half of incident parallel light, i.e. half-reflecting and half-transmitting mirror, and the light intensity of the parallel light is attenuated to a certain extent and then received by the photodetector 5.

In this embodiment, the photodetector 5 is, for example, a CCD. The CCD (Charge Coupled Device) is composed of a series of closely arranged MOS capacitors, and its outstanding feature is to use Charge as a signal to realize Charge storage and Charge transfer. In the CCD, charge packets are formed by minority carriers generated by absorption of incident photons by the silicon substrate, and thus the CCD has good photoelectric conversion characteristics. Meanwhile, the CCD also has a good spectrum effect, when the first detection light and the second detection light are received by the CCD, an interference phenomenon is generated, a plurality of light and dark stripes appear, so that a spectrum response curve has a plurality of wave crests and wave troughs, namely fluctuation occurs, and then the number of the moving stripes can be input into the center of the view field through an electric signal.

Further, the flexible pendulum piece displacement testing device further comprises a converging lens group 6, and the first detection light and the second detection light are received by the photoelectric detector after being converged by the converging lens group 6.

In this embodiment, the light splitting plate 3 and the incident direction of the parallel light are arranged at an angle of 45 °, the first mirror group 4 is parallel to the incident direction of the parallel light, and the flexible pendulum piece 1 is perpendicular to the incident direction of the parallel light.

Furthermore, because the pendulum tongue 10 is made of quartz glass, the light transmittance of the quartz glass is good, and in order to improve the calculation accuracy of the displacement of the flexible pendulum piece 1 affected by the temperature, the thermal expansion error of the flexible pendulum piece 1 caused by the temperature change of the coil 11 is also considered in the present application.

Specifically, referring to fig. 3, fig. 3 is a schematic diagram illustrating a thermal expansion error test provided by an embodiment of the present invention, a region of the pendulum tongue 10 not covered by the gold-plated thin film is a transmission region 110, the flexible pendulum displacement test apparatus further includes a second mirror group 7, parallel light emitted by the light source 2 is reflected and transmitted by the beam splitter 3 to form a third detection light and a fourth detection light, respectively, the third detection light is reflected to the first mirror group 4 through the beam splitter 3, reflected by the first mirror group 4, passes through the beam splitter 3 again, and is received by the photodetector 5 after being transmitted by the beam splitter 3, the fourth detection light is transmitted to the transmission region 110 through the beam splitter 3, transmitted to the second mirror group 7 through the transmission region 110, and reflected to the transmission region 110 through the second mirror group 7, the light is transmitted to the spectroscopic plate 3 through the transmission region 110, and then is reflected by the spectroscopic plate 3 and received by the photodetector 5, a thermal expansion error of the flexible pendulum piece 1 at a set temperature is obtained according to the optical path information received by the photodetector 5, and a second displacement of the flexible pendulum piece 1 is obtained according to the first displacement of the flexible pendulum piece 1 and the thermal expansion error.

The area of the pendulum tongue 10 not covered by the gold-plated film is equivalent to a transmission mirror, the third detection light and the fourth detection light converge to generate interference due to different optical paths, interference fringes are formed and are detected by the optical photoelectric detector 5, when the temperature of the coil 11 changes, the pendulum tongue 10 is thermally expanded due to heat conduction, so that the optical path difference observed by the optical photoelectric detector 5 also changes, and the displacement of the flexible pendulum piece 1 of the quartz accelerometer, which is affected by the temperature, is extremely small, so that the thermal expansion error can be eliminated on the basis of the first displacement, and a second displacement which is more accurate can be obtained. And during specific calculation, subtracting the thermal expansion error from the first displacement to obtain a second displacement at the set temperature.

For example, when the optical path distance of the second detection light is reduced by a thermal expansion error generated in the flexible pendulum piece 1, if a stripe of equal thickness is observed, the stripe moves in a direction of a thicker film; if isocline fringes are observed, the fringes shrink towards the center. The thermal expansion error generated by the flexible pendulum plate 1 is in/2 for every moving stripe. Therefore, the thermal expansion error of the flexible pendulum piece 1 of the quartz accelerometer, which is influenced by temperature, can be related to the wavelength lambda of parallel light by using optical phase detection, and the expression is as follows:

Δh₂＝Nλ/2

wherein,. DELTA.h₂The thermal expansion error of the flexible pendulous reed 1 at the set temperature is shown, N is the number of the field-of-view center moving stripes in the photoelectric detector 5, and lambda is the wavelength of the parallel light emitted by the light source 2.

Calculating to obtain a first displacement delta h of the flexible pendulum piece 1 at the set temperature₁And a thermal expansion error Δ h of the flexible pendulum piece 1 at the set temperature₂Then the second displacement Δ h of the flexible pendulum piece 1 at the set temperature₃＝Δh₁-Δh₂。

With reference to fig. 1 and fig. 3, the flexible pendulum piece displacement testing apparatus further includes two identical fixtures 8, each fixture 8 includes a movable fixing base 81, a height-adjustable supporting frame 82, and a hollow ring 83, the supporting frame 82 is connected to the fixing base 81 and the hollow ring 83, and the outer ring 13 is sandwiched between the hollow rings 83 of the two fixtures 8. The fixing device 8 is used for fixing the flexible pendulum piece 1, and meanwhile, by moving the fixing base 81 and adjusting the height of the supporting frame 82, the position of the second detection light hitting the reflection area 100 can be changed. Since the lower end of the swing tongue 10 swings relative to the upper end (fixed end) of the swing tongue 10, the vertical distances from the test points at different positions on the reflection area 100 to the fixed end of the swing tongue 10 are not completely the same, and the first displacement and the second displacement calculated from the test points at different positions are not completely the same.

Through carrying out a plurality of experiments on different test points of the second detection light, wherein the different test points are arranged on the reflection area 100, the first displacement of each test point at a set temperature can be obtained according to the light path information received by the photoelectric detector 5, so as to obtain the second displacement of each test point at the set temperature, and then least square fitting is carried out on the data of the second displacements corresponding to all the test points, so that the nonlinear error generated by the flexible pendulum piece 1 due to the temperature change of the coil 11 can be eliminated, and the third displacement of the flexible pendulum piece 1 can be obtained.

Based on the flexible pendulous reed displacement testing device, please refer to fig. 1-2, the application also provides a flexible pendulous reed displacement testing method, which is used for testing the displacement of the flexible pendulous reed 1 of the quartz accelerometer, which is affected by the temperature, and comprises the following steps:

step S1, adjusting the positions of the light splitting plate 3, the first reflector group 4, the flexible swinging sheet 1 and the photoelectric detector 5;

step S2, setting the temperature of the coil 11 of the flexible pendulous reed 1 through a temperature regulator;

step S3, the light source 2 is started, so that parallel light emitted by the light source 2 is reflected and transmitted by the spectroscopic plate 3 to form first detection light and second detection light, respectively, the first detection light is reflected by the spectroscopic plate 3 to the first reflector set 4, reflected by the first reflector set 4, passes through the spectroscopic plate 3 again, is transmitted by the spectroscopic plate 3, and is received by the photodetector 5, the second detection light is transmitted by the spectroscopic plate 3 to the reflection area 100 of the flexible pendulum piece 1, reflected by the reflection area 100, passes through the spectroscopic plate 3 again, is reflected by the spectroscopic plate 3, and is received by the photodetector 5, and a first displacement of the flexible pendulum piece 1 at a set temperature is obtained according to optical path information received by the photodetector 5.

First, step S1 is executed to adjust the positions of the beam splitter 3, the first mirror group 4, the flexible pendulum plate 1 and the photodetector 5. In this embodiment, the light splitting plate 3 and the incident direction of the parallel light are arranged at an angle of 45 °, the first mirror group 4 is parallel to the incident direction of the parallel light, and the flexible pendulum piece 1 is perpendicular to the incident direction of the parallel light.

Then, step S2 is executed to set the temperature of the coil 11 of the flexible balance staff 1 by the temperature regulator. The temperature regulator is used for measuring temperature change generated by electrifying the coil 11 when the quartz accelerometer measures acceleration so as to test the displacement of the flexible pendulous reed 1 affected by temperature, the temperature regulator is for example a thermostat, and the flexible pendulous reed 1 is placed in the thermostat. Of course, the temperature regulator may also adopt other devices capable of regulating the temperature change of the coil 11, such as a device for electrifying the coil 11.

Referring to fig. 3, the flexible pendulous reed displacement testing apparatus further includes a second mirror set 7, and after the step S2 is executed and before the step S3 is executed, the flexible pendulous reed displacement testing method further includes:

the light source 2 is started to make the parallel light emitted by the light source 2 form a third detecting light and a fourth detecting light after being reflected and transmitted at the light splitting plate 3, the third detection light is reflected to the first reflecting mirror group 4 through the beam splitter 3, reflected by the first reflecting mirror group 4, passes through the beam splitter 3 again, is transmitted by the beam splitter 3, and is received by the photodetector 5, the fourth detection light is transmitted to the transmission area 110 through the spectroscopic plate 3, transmitted to the second reflecting mirror group 7 through the transmission area 110, reflected to the transmission area 110 through the second reflecting mirror group 7, transmitted to the spectroscopic plate 3 through the transmission area 110, reflected by the spectroscopic plate 3 and received by the photodetector 5, and acquiring the thermal expansion error of the flexible pendulum piece 1 at the set temperature according to the optical path information received by the photoelectric detector 5.

In the process, the area of the pendulum tongue 10 not covered by the gold-plated film is equivalent to a transmission mirror, the third detection light and the fourth detection light converge with different optical paths to generate interference, interference fringes are formed and are detected by the optical photoelectric detector 5, when the temperature of the coil 11 changes, the pendulum tongue 10 is thermally expanded due to heat conduction, so that the optical path difference observed by the optical photoelectric detector 5 also changes, and the displacement of the flexible pendulum piece 1 of the quartz accelerometer affected by the temperature is extremely small, so that the thermal expansion error is eliminated on the basis of the first displacement, and a more accurate second displacement can be obtained.

For example, when the optical path distance of the second detection light is reduced by a thermal expansion error generated in the flexible pendulum piece 1, if a stripe of equal thickness is observed, the stripe moves in a direction of a thicker film; if isocline fringes are observed, the fringes shrink towards the center. The thermal expansion error generated by the flexible pendulum plate 1 is in/2 for every moving stripe. Therefore, the thermal expansion error of the flexible pendulum piece 1 of the quartz accelerometer, which is influenced by temperature, can be related to the wavelength lambda of parallel light by using optical phase detection, and the expression is as follows:

Δh₂＝Nλ/2

wherein,. DELTA.h₂The thermal expansion error of the flexible pendulous reed 1 at the set temperature is shown, N is the number of the field-of-view center moving stripes in the photoelectric detector 5, and lambda is the wavelength of the parallel light emitted by the light source 2.

Then, step S3 is executed again, the light source 2 is started, so that parallel light emitted by the light source 2 is reflected and transmitted by the spectroscopic plate 3 to form first detection light and second detection light, respectively, the first detection light is reflected by the spectroscopic plate 3 to the first reflector group 4, is reflected by the first reflector group 4, passes through the spectroscopic plate 3 again, is transmitted by the spectroscopic plate 3, and is received by the photodetector 5, the second detection light is transmitted by the spectroscopic plate 3 to the reflection area 100 of the flexible pendulum piece 1, is reflected by the reflection area 100, passes through the spectroscopic plate 3 again, is reflected by the spectroscopic plate 3, and is received by the photodetector 5, and a first displacement of the flexible pendulum piece 1 at a set temperature is obtained according to light path information received by the photodetector 5.

When the temperature of the coil 11 changes, the flexible pendulum piece 1 generates a small displacement, the first detection light and the second detection light converge with different optical paths to generate interference, and interference fringes are formed and detected by the optical photodetector 5, so that the displacement of the flexible pendulum piece 1 affected by the temperature can be calculated according to the optical path change observed in the photodetector 5. For example, when the light path distance of the second detection light is reduced by the minute displacement of the flexible pendulum piece 1, if a stripe of equal thickness is observed, the stripe moves in the direction of the thicker film; if isocline fringes are observed, the fringes shrink towards the center. The small displacement of the flexible pendulum 1 is λ/2 for each movement of one stripe. Therefore, the displacement of the flexible pendulous reed 1 of the quartz accelerometer influenced by temperature can be related to the wavelength lambda of parallel light by using optical phase detection, and the expression is as follows:

Δh₁＝Nλ/2

wherein,. DELTA.h₁For the first displacement of the flexible pendulous reed 1 at the set temperature, N is the number of field center shift stripes in the photoelectric detector 5, and λ is the wavelength of the parallel light emitted by the light source 2.

After the step S3 is executed, the flexible pendulum piece displacement testing method further includes:

step S4, obtaining a second displacement of the flexible pendulum plate 1 according to the first displacement of the flexible pendulum plate 1 and the thermal expansion error, wherein the step is to eliminate the influence of the thermal expansion error.

In this embodiment, the calculation formulas of the first displacement and the thermal expansion error of the flexible pendulum piece 1 at the set temperature are as follows:

Δh＝Nλ/2

wherein Δ h is a first displacement or thermal expansion error of the flexible pendulous reed 1 at the set temperature, N is the number of field center movement stripes in the photodetector 5, and λ is the wavelength of the parallel light emitted by the light source 2.

In combination with the above, the first displacement Δ h of the flexible pendulum piece 1 at the set temperature is obtained by calculation₁The thermal expansion error delta h of the flexible pendulum piece 1 at the set temperature₂Then the second displacement Δ h of the flexible pendulum piece 1 at the set temperature₃＝Δh₁-Δh₂。

After the step S4 is completed, the flexible pendulum piece displacement testing method further includes:

step S5, adjusting the position of the flexible pendulum piece 1 to enable the second detection light to irradiate on test points at different positions of the reflection area 100, wherein the vertical distances from the test points to the fixed end of the pendulum tongue 10 are different;

s6, repeating the steps S3-S4 to obtain second displacements corresponding to different test points;

and step S7, performing least square fitting on the data of the second displacements corresponding to all the test points to obtain a third displacement of the flexible balance staff 1.

Referring to fig. 4, fig. 4 is a schematic diagram illustrating a distribution of test points according to an embodiment of the present invention. It should be understood that, since the lower end of the swing tongue 10 swings relative to the upper end (fixed end) of the swing tongue 10, the vertical distances from the test points 200 at different positions on the reflection area 100 to the fixed end of the swing tongue 10 are not completely the same, and the first displacement and the second displacement calculated from the test points at different positions are not completely the same. The vertical distance referred to here is the distance between the test point 200 and the fixed end of the swing tongue 10 in the vertical direction, i.e., the up-down direction shown in fig. 4.

Preferably, since the coil 11 is fixed to the central portion of the swing tongue 10, a certain number of test points 200 can be selected around the coil 11.

Step S5 can be performed by moving the fixing base 81 of the fixer 8 back and forth and left and right and adjusting the height of the supporting frame 82.

And then executing the step S6 to obtain second displacements corresponding to different test points, executing the step S7 to perform least square fitting on the data of the second displacements corresponding to all the test points to obtain a third displacement of the flexible pendulum piece 1, so that the finally obtained displacement of the flexible pendulum piece 1 affected by the temperature is higher in calculation accuracy.

Further, the flexible pendulum piece displacement test method further comprises the following steps:

the temperature of the coil 11 of the flexible pendulum piece 1 is adjusted through a temperature adjuster, and then the steps are repeated, so that the first displacement, the second displacement and the third displacement of the flexible pendulum piece 1 at different temperatures of the coil 11 can be obtained.

In summary, the embodiment of the invention provides a displacement testing device and a displacement testing method for a flexible pendulous reed, which are used for measuring the tiny displacement of the flexible pendulous reed of a quartz accelerometer, which is influenced by temperature, by simulating the temperature change of a coil and adopting an optical phase measurement method, and solve the problems of low resolution, large noise, low precision and slow response time caused by time integration in the traditional capacitance detection method, thereby improving the output precision of the quartz accelerometer.

It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the protection scope of the technical solution of the present invention, unless the content of the technical solution of the present invention is departed from.