CN116448086B - Optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection - Google Patents
Optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection Download PDFInfo
- Publication number
- CN116448086B CN116448086B CN202310715456.5A CN202310715456A CN116448086B CN 116448086 B CN116448086 B CN 116448086B CN 202310715456 A CN202310715456 A CN 202310715456A CN 116448086 B CN116448086 B CN 116448086B
- Authority
- CN
- China
- Prior art keywords
- microsphere
- suspension
- laser
- light
- rotor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000004005 microsphere Substances 0.000 title claims abstract description 188
- 230000003287 optical effect Effects 0.000 title claims abstract description 82
- 239000000725 suspension Substances 0.000 title claims abstract description 65
- 238000001514 detection method Methods 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 claims abstract description 8
- 230000010287 polarization Effects 0.000 claims description 58
- 230000008859 change Effects 0.000 claims description 28
- 239000011521 glass Substances 0.000 claims description 20
- 239000013078 crystal Substances 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 14
- 238000003384 imaging method Methods 0.000 claims description 12
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 4
- 229910021532 Calcite Inorganic materials 0.000 claims description 3
- 239000010453 quartz Substances 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 13
- 238000011161 development Methods 0.000 abstract description 2
- 238000005259 measurement Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000002245 particle Substances 0.000 description 8
- 230000000875 corresponding effect Effects 0.000 description 7
- 230000033001 locomotion Effects 0.000 description 7
- 238000013016 damping Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000004044 response Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 238000007667 floating Methods 0.000 description 3
- 238000005286 illumination Methods 0.000 description 3
- 239000011859 microparticle Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 210000001747 pupil Anatomy 0.000 description 2
- 238000005411 Van der Waals force Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005339 levitation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000003534 oscillatory effect Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/02—Rotary gyroscopes
- G01C19/04—Details
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Gyroscopes (AREA)
Abstract
The application discloses an optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection, which comprises a laser light source, an optical modulation unit, a capturing suspension unit and a detection unit which are sequentially arranged according to a laser light path. The application also discloses a method for using the optical suspension microsphere rotor gyroscope, which greatly simplifies the complexity of an optical path under the low noise advantage of an optical suspension technology, and realizes suspension and attitude angle detection of the birefringent microsphere rotor simultaneously by utilizing single-beam laser, thereby having great development potential.
Description
Technical Field
The application relates to the technical field of gyroscopes, in particular to an optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection.
Background
The gyroscope plays a very important role in the field of inertial navigation, and can realize full-autonomous inertial navigation by combining with the accelerometer without communicating with the outside. Therefore, the performance parameters of the gyroscope directly determine the accuracy of inertial navigation, which is important in engineering practice. Currently, the mainstream gyroscopes comprise a mechanical rotor gyroscope, a vibrating gyroscope, an optical gyroscope and an atomic gyroscope, wherein the development history of the mechanical rotor gyroscope is longest, but the gyroscope precision of the mechanical rotor gyroscope is kept at a leading level all the time. The earliest rotor gyroscopes utilize common mechanical bearings to support the rotor for high-speed rotation and for dead axle. According to a specific working principle, the dead axle of the high-speed rotor can be directly utilized to measure the movement included angle between the carrier and the rotating shaft of the rotor, so that the direct measurement of angular movement, namely the angle gyro, is realized. The torquer can be arranged in the orthogonal direction of the gyro rotation shaft to form a closed loop, and the torquer is controlled according to the input angular velocity so that the rotation shaft can follow the movement of the carrier to realize the measurement of acceleration, namely the angular velocity gyro. The friction force between the rotor and the bearing is a main error source of the mechanical rotor gyro, so in order to improve the precision of the rotor gyro, a liquid floating bearing, an air floating bearing, a magnetic floating bearing and an electrostatic bearing are sequentially provided, and the rotor and the bearing are separated by utilizing different suspension technologies, so that the friction force is reduced, and the purpose of improving the performance precision of the gyro is achieved.
In recent years, the optical levitation technology has gradually moved into the field of inertial navigation. The light suspension technology has the advantages that the light suspension technology suspends the microparticles in the air, so that the environmental noise is well isolated, and the superiority of the light suspension technology is verified in various precision measurement fields. Meanwhile, spin angular momentum transfer based on circularly polarized light drives the microsphere to rotate, so that the particle can be driven to GHz rotation speed in a vacuum environment. Thus, gyroscopic technology based on optically suspended rotors follows. At present, the existing optical suspension rotating micro-particle gyroscope is based on a multi-beam realization gyroscopic effect, for example, a device for measuring angular velocity of an optical suspension rotor micro-gyroscope is disclosed in Chinese patent publication No. CN104034322A, which is essentially based on an optical suspension rotor gyroscope of a three-dimensional vortex optical trap system, and after particles are stably captured by utilizing an optical suspension technology, attitude angle measurement is realized according to a detection pattern prepared on a microsphere, and then the attitude of the microsphere is adjusted by utilizing vortex optical rotation so as to work in a closed-loop state to realize angular velocity measurement. Six lasers are needed to achieve the gyroscopic effect, symmetrical patterns are needed to be prepared on the micrometer-sized balls in the detection of the attitude angle, the requirements on the preparation of a light path system and the preparation of microspheres are particularly high, and the performance accuracy of the gyroscope is extremely easy to influence by the parameters. As disclosed in chinese patent publication No. CN110514191a, a micro-electromechanical suspended rotating micro-particle gyroscope is disclosed, which uses three lasers to measure the attitude angle of particles in the optical suspended gyroscope scheme of the micro-electromechanical technology, and the measurement signal depends on the surface morphology of the microsphere, so as to limit the detection accuracy. For example, chinese patent publication No. CN 109059892B discloses a photon suspension gyro based on a double-beam optical trap system, which uses linear polarization and birefringent microspheres to measure the deflection angle of the photon suspension gyro, but requires three incident lasers and two photodetectors. On the one hand, the existing patents have the defects that the whole structure is complex due to multiple light beams, the difficulty of light path adjustment is increased, the unstable factors are increased, and the stability of the structure is not realized. On the other hand, in the working principle of the gyroscope, the influence of the optical orientation moment on the stability of the attitude angle is not considered, and when the external angle input exists, the included angle between the maximum principal axis of inertia of the particles and the linear polarization direction is unstable, so that the accuracy of the gyroscope is greatly influenced.
Disclosure of Invention
Aiming at the defects of the prior art, the application provides the light suspension microsphere rotor gyroscope based on the detection of the attitude angle of the optical axis, which utilizes one laser beam to realize suspension, driving and signal detection of the microsphere rotor simultaneously based on the rule of influence of the microsphere optical axis on the polarization state of the laser, thereby reducing the complexity of an optical path.
In order to solve the technical problems, the application adopts the following technical scheme:
the light suspension microsphere rotor gyroscope based on the optical axis attitude angle detection comprises a laser light source, a light modulation unit, a capture suspension unit and a detection unit which are sequentially arranged according to a laser light path, wherein laser emitted by the laser light source is adjusted by the light modulation unit and then is used for capturing microspheres in the capture suspension unit, the detection unit is used for detecting the attitude angle of the microspheres, the light modulation unit comprises a beam expander system, a dichroic mirror and a 1/4 wave plate which are sequentially arranged according to the laser light path, and the light modulation system is used for adjusting the polarization state of the laser into a circularly polarized light state; the capturing suspension unit comprises a vacuum cavity, a focusing objective lens, a vibrating piece and an imaging objective lens, wherein the focusing objective lens, the vibrating piece and the imaging objective lens are positioned in the vacuum cavity and are sequentially arranged according to a laser light path, the microsphere is placed on the vibrating piece capable of vibrating, and can be thrown and suspended above the vibrating piece when the vibrating piece vibrates, and the microsphere is prepared by adopting a birefringent crystal material; the detection unit comprises a polarization beam splitter prism, a photoelectric detector and a data acquisition device electrically connected with the photoelectric detector, which are arranged in sequence according to a laser light path.
As a further improvement of the above technical scheme:
the light suspension microsphere rotor gyroscope further comprises an observation unit, wherein the observation unit comprises a visible light source and an image capturing device, and the visible light source and the image capturing device are respectively positioned at the front end of the laser inlet and the rear end of the laser outlet of the vacuum cavity.
The dichroic mirror and the 1/4 wave plate are arranged between the visible light source and the front end of the laser inlet of the vacuum cavity.
The light suspension microsphere rotor gyroscope further comprises an optical filter and a reflecting mirror which are arranged in sequence according to a laser light path, wherein the optical filter is positioned between the image capturing device and the vacuum cavity, and the reflecting mirror is positioned between the polarization beam splitter prism and the optical filter.
The beam expander system comprises two beam expanders, and the convex surfaces of the beam expanders are arranged in opposite directions.
The birefringent crystal material is one of vaterite, calcite and quartz crystal material; the microsphere is ellipsoidal in shape.
The image capturing device is arranged at the back focal length of the imaging objective lens.
The vibration piece comprises a glass sheet and a piezoelectric sheet, wherein the microspheres are positioned on the glass sheet, the piezoelectric sheet is connected with the glass sheet, and the thickness of the glass sheet is matched with the focal length of the focusing objective lens.
The application also provides a use method of the optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection, which comprises the following steps:
step S1, a laser light source is turned on to vibrate a vibrating piece so that microspheres are separated from the vibrating piece, and the microspheres are captured;
s2, adjusting a 1/4 wave plate of the light modulation unit until the polarization state of laser is adjusted to be in a circularly polarized light state, and driving the microsphere to rotate;
and S3, inputting the angular velocity, and detecting the laser power change after the polarization beam splitter prism is detected by a photoelectric detector of the detection unit to obtain microsphere attitude angle information, thereby realizing detection of microsphere rotation signals.
As a further improvement of the above technical scheme:
step A1 is further included between the step S2 and the step S3, and the step A1 is as follows: and (3) opening the vacuum pump, reducing the air pressure in the vacuum cavity until the rotating speed of the microspheres reaches a first threshold value, and closing the vacuum pump to stabilize the rotating speed of the microspheres.
In the step S3, the direction of change of the attitude angle information is perpendicular to the measured angular velocity Ω, and the size of the attitude angle is Ω H/k, where H is the angular momentum of the microsphere, and k is the stiffness of the optical torque spring.
Compared with the prior art, the application has the advantages that:
the application discloses an optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection, which comprises a laser light source, a light modulation unit, a capturing suspension unit and a detection unit which are sequentially arranged according to a laser light path, wherein the light modulation unit is used for capturing suspension microspheres after adjusting the polarization state of laser emitted by the laser light source into a circularly polarized light state, the detection unit is used for detecting the attitude angle of the microspheres, and the optical suspension microsphere rotor gyroscope is mainly designed based on the optical suspension technology, the rotation driving technology and the attitude angle detection technology of the microspheres and comprehensively considers the dynamic response of the microsphere rotor to the input angular speed, the modulation effect of the polarization state of the laser and other factors. After the laser beam is expanded and focused, the suspension of the microsphere is realized in the vacuum cavity, and the scattered light transmitted through the microsphere is led into the photoelectric detector, so that the suspension driving and the detection of the microsphere are realized by utilizing a single laser beam. When the microspheres are stably suspended and driven to rotate at a high speed, after the angular velocity is input in a plane perpendicular to the rotation axis, the spatial attitude of the microspheres can generate an offset angle in the orthogonal direction of the angular velocity due to the self-stabilization effect of the orientation moment. The change of the microsphere posture is measured based on the modulation effect of the optical axis posture angle of the birefringent material on the laser polarization state, and the input angular velocity can be measured through resolving.
Drawings
The accompanying drawings are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain, without limitation, the embodiments of the application. In the drawings:
FIG. 1 is a schematic diagram of an overall structure of an optical suspension microsphere rotor gyroscope system according to the present application;
FIG. 2 is a kinetic model of a microsphere rotor according to the present application;
FIG. 3 is a schematic diagram of the operation of an optical suspension microsphere rotor gyroscope according to the present application;
FIG. 4 is a schematic diagram of the principle of detecting the attitude angle of the microsphere rotor in the application;
FIG. 5 shows the output test results of the microsphere rotor according to the present application for input angular velocity.
Reference numerals illustrate: 1. a laser light source; 11. an imaging objective; 12. a light filter; 13. an image capturing device; 14. a reflecting mirror; 15. a polarization beam splitting prism; 16. a photodetector; 17. a data acquisition device; 2. a beam expander system; 21. a beam expander; 3. a visible light source; 4. a dichroic mirror; 5. a 1/4 wave plate; 6. a vacuum chamber; 7. a focusing objective lens; 9. a microsphere; 10. a vibrating member; 101. a glass sheet; 102. a piezoelectric sheet.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art without inventive effort, are intended to be within the scope of the present application, based on the embodiments herein.
In the description of the present application, it should be noted that, the terms "center," "upper," "lower," "horizontal," "inner," "outer," "top," "bottom," and the like indicate an orientation or a positional relationship based on that shown in the drawings, and are merely for convenience of description and to simplify the description, rather than indicate or imply that the apparatus or elements being referred to must have a specific orientation, be constructed and operate in a specific orientation, and thus should not be construed as limiting the present application.
As shown in fig. 1 and fig. 2, the optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection in this embodiment includes a laser light source 1, a light modulation unit, a capturing suspension unit and a detection unit sequentially arranged in order of a laser light path, laser light emitted by the laser light source 1 is adjusted by the light modulation unit and then used for capturing microspheres 9 in the capturing suspension unit, the detection unit is used for detecting attitude angles of the microspheres 9, the light modulation unit includes a beam expander system 2, a dichroic mirror 4 and a 1/4 wave plate 5 sequentially arranged in order of the laser light path, and the light modulation system is used for adjusting a polarization state of the laser light into a circularly polarized light state; the capturing and suspending unit comprises a vacuum cavity 6, a focusing objective lens 7, a vibrating piece 10 and an imaging objective lens 11 which are positioned in the vacuum cavity 6 and are arranged in sequence according to a laser light path, wherein the microsphere 9 is placed on the vibrating piece 10 capable of vibrating, and when the vibrating piece 10 vibrates, the microsphere 9 can be thrown and suspended above the vibrating piece 10, and the microsphere 9 is prepared by adopting a birefringent crystal material; the detection unit includes a polarization beam splitter prism 15, a photodetector 16, and a data acquisition device 17 electrically connected to the photodetector 16, which are disposed in the order of the laser light path.
In this embodiment, the focusing objective 7 and the imaging objective 11 are located in the vacuum chamber 6, since the numerical aperture of the focusing objective 7 is larger than 1, which results in a very short focal length (one hundred microns). If the focusing objective 7 and the imaging objective 11 are placed outside the vacuum chamber 6, it is necessary that the wall thickness of the vacuum chamber 6 is smaller than the focal length dimension, which may result in a too thin chamber here to achieve a high vacuum.
In this embodiment, the optical suspension microsphere rotor gyroscope further includes an observation unit, where the observation unit includes a visible light source 3 and an image capturing device 13, and the visible light source 3 and the image capturing device 13 are respectively located at the front end of the laser inlet and the rear end of the laser outlet of the vacuum chamber 6. In this embodiment, the visible light source 3 is an illumination lamp, and the image capturing device 13 is a camera.
In the present embodiment, the dichroic mirror 4, the 1/4 wave plate 5 are provided between the visible light source 3 and the laser entrance front end of the vacuum chamber 6. The dichroic mirror 4 reflects laser light emitted from the laser to the focusing objective 7 for suspension capture of the microsphere 9 rotor, and transmits illumination light emitted from the visible light source 3 so that the illumination light can illuminate the microsphere, thereby realizing observation by the image capturing device 13.
In this embodiment, the optical suspension microsphere rotor gyroscope further includes an optical filter 12 and a reflecting mirror 14, which are arranged in order of the laser path, the optical filter 12 is located between the image capturing device 13 and the vacuum chamber 6, and the reflecting mirror 14 is located between the polarization beam splitter prism 15 and the optical filter 12.
In this embodiment, the beam expander system 2 includes two beam expanders 21, and the convex surfaces of the beam expanders 21 are disposed opposite to each other. The laser beam enters the first beam expander 21 to be focused, and then enters the second beam expander 21 to be expanded to obtain a light spot with a size equivalent to the pupil size of the focusing objective lens 7, and in the embodiment, the thickness of the two beam expanders 21 is different, and the focal lengths are not equal.
In this embodiment, the birefringent crystal material is one of vaterite, calcite, and quartz crystal material; the birefringent crystal material is subjected to the action of driving moment and orientation moment under the action of circularly polarized laser, and the optical axis of the microsphere 9 is oriented to be perpendicular to the plane of laser propagation while the microsphere 9 is driven to rotate. The microsphere 9 is in an ellipsoidal shape, the optical axis of the microsphere 9 is not coincident with the geometric principal axis (the geometric principal axis represents the long axis of the microsphere 9 on the particle geometric shape, the optical axis is the growth direction of the birefringent crystal, the growth direction of the crystal cannot be controlled, and the coincidence with the geometric principal axis is difficult to ensure), so that the centrifugal moment and the directional moment are balanced when the microsphere 9 rotates at a high speed, and the included angle between the optical axis of the microsphere and the propagation direction of laser is ensured to be unequal to 90 degrees.
In the present embodiment, the image capturing device 13 is disposed at the back focal length of the imaging objective lens 11.
In this embodiment, the vibrating member 10 includes a glass sheet 101 and a piezoelectric sheet 102, the microspheres 9 are located on the glass sheet 101, the piezoelectric sheet 102 is connected to the glass sheet 101, and the thickness of the glass sheet 101 matches the focal length of the focusing objective 7.
In the prior art, additional laser beams are required to detect the attitude angle, so multiple laser beams are required. Compared with the realization of the gyroscopic effect by multiple laser beams, the realization of the gyroscopic effect by a single laser beam has the difficulty of detecting the attitude angle of the gyroscope. The signal of the optical axis attitude angle is obtained by the change of the light intensity signal measured by the photoelectric detector, but the change is caused by the fact that the microsphere 9 adopts a birefringent crystal material and the optical axis attitude angle of the microsphere 9 modulates the laser polarization state, and the detection of the attitude angle is realized by utilizing the corresponding relation between the optical axis of the microsphere 9 particles and the laser polarization information, so that an additional laser beam is not needed.
The principle of the application is as follows: 1) Suspension and rotation driving of microsphere 9 rotor
As shown in fig. 1, the laser emitted by the laser light source 1 passes through the beam expander system 2 to obtain a spot with a size corresponding to the pupil size of the focusing objective lens 7. The focusing objective 7 used should be chosen as large as possible in numerical aperture to reduce the beam diameter as much as possible to obtain a large light intensity gradient for stable capturing. After the laser passes through the microsphere 9, the imaging objective lens 11 collects the laser and collimates the laser so as to detect the motion signal of the microsphere 9 by a subsequent light path. The image capturing device 13 is mounted on the back focal length of the imaging objective lens 11 to observe the suspended microspheres 9 in real time. The microspheres 9 are placed on a thin glass sheet 101, the thickness of the glass sheet 101 being matched to the focal length of the focusing objective 7 and the light transmittance being high in order to achieve stable suspension. The size of the microspheres 9 is small, so that large van der Waals forces exist between the microspheres 9 and between the microspheres 9 and the glass sheet 101, and particles cannot be directly captured from the surface in the air. Glass sheet 101 is fixed to circular piezoelectric sheet 102 and microspheres 9 are separated from glass sheet 101 by vibration to achieve capture.
After capturing the microsphere 9, the polarization state of the laser is adjusted to circular polarization by adjusting the 1/4 wave plate 5 in front of the focusing objective lens 7, so as to drive the microsphere 9 to rotate. The light path of the rotation signal of the detection microsphere 9 is reflected to the position of the polarization beam splitter prism 15 after passing through the optical filter 12, and the laser power after passing through the polarization beam splitter prism 15 is changed along with the change of the polarization direction. At this time, the microsphere 9 is similar to a rotating wave plate, and has a periodic modulation function on the polarization state of laser light, so that the rotation signal of the microsphere 9 can be detected by detecting the laser power change of the polarization beam splitter prism 15 by using the photoelectric detector 16.
2) Dynamic response characteristics of microsphere 9 rotor to input angular velocity (microsphere 9 rotor gyro principle of operation)
As shown in fig. 2, the coordinate system of the optical suspension microsphere 9 is defined, the origin of the coordinates is the center of the microsphere 9, and the xyz axis is the radial direction of the microsphere 9. Hereinafter I j (j=x, y, z) represents moment of inertia, k j Representing the optical torque spring rate, c j Indicating the rotation damping coefficient, Ω, of the microsphere 9 j Indicating the angular velocity of the input, and α and β indicate the angle of rotation of the microsphere along the y-axis and x-axis, respectively. Wherein the positive rotation of α coincides with the y-axis, but the positive rotation of β is opposite to the x-axis. Assuming that the laser propagates in the positive direction along the z-axisSowing, the microsphere rotates around the z axis at angular velocity omega under the action of the driving moment of circularly polarized light, and the moment of inertia of the microsphere 9 is H=I z ω。
The moment applied to the microsphere 9 in the x-axis direction comprises moment-I corresponding to angular acceleration x Ω' x ，I x Beta '', gyro moment-H omega y -hα', damping moment c x Beta', elastic directional moment k x Beta. The moment experienced in the y-axis direction is similar. For an ideal circularly polarized gaussian beam, the torque elastic coefficients of the microsphere 9 in different directions are equal, i.e. k x =k y =k. The ellipsoidal error of the microsphere 9 has limited influence on the rotation damping, so the damping coefficient can be approximately equal to c x =c y =c. Assuming that the input angular velocity is a constant value, the moment-I corresponding to the angular acceleration x Ω' x Can be ignored. And I x Beta″ corresponds to the nutation of the spindle of the microsphere 9, which is negligible since it has a frequency twice the rotational speed and a smaller amplitude. Further reduced to angular velocity omega in the x-axis direction only x The motion equation after the simplification of the microsphere 9 rotor is obtained by inputting is as follows:
solving to obtain
It can be seen that the axis of rotation of the microsphere 9 will be responsive about both the x and y axes when the x axis is input at angular velocity. But in the same direction of the input signal, i.e. rotated about the x-axis, the angle beta is a gradually decaying oscillatory rotation and eventually zero, where t is time. While the angle alpha of rotation about the y-axis, although also having an oscillating term, eventually produces a stable offset angle omega x H/k。
From the above analysis it was found that after inputting the angular velocity in a certain direction, a stable angle will be created in the orthogonal direction. Due to the included angle, the microsphere 9 (i.e., the rotor) is subjected to a forceAn elastic moment, which causes the rotor to precess to follow the input angular velocity, thereby achieving a steady state. In this state, the angle β=Ω in the orthogonal direction of the detection microsphere 9 is detected x H/k, the input angular velocity omega can be obtained x The size of the carrier is measured, so that the rotation speed of the rotor of the optical suspension microsphere 9 is measured. As shown in fig. 3, this process can be further explained as: gyro moment M Gyroscope And directional feedback moment M Feedback of Balance. When the angular velocity Ω x When input in the x-axis direction, the rotating microsphere 9 generates gyroscopic torque M relative to the y-axis direction Gyroscope = HΩ x . The gyroscopic torque drives the rotor away from the original equilibrium position, thus creating additional directional feedback torque to balance the gyroscopic torque. The deflection angle α finally reaches a new stable position, in which the directional feedback torque M Feedback of Kα equals gyro moment hΩ x And in opposite directions. In this case, α=Ω is obtained x The output expression of H/k, i.e., the expression of the attitude angle.
3) Attitude angle detection technology of microsphere 9 rotor
Fig. 4 is a schematic diagram of measurement of the attitude angle of the rotor optical axis of the microsphere 9. When the optical axis is close to the transverse plane (circular polarization) of the laser, the amplitude of the rotation signal is large and the frequency is high. Therefore, the spatial attitude angle of the optical axis of the microsphere 9 can be read out by the rotation signal. For the microballoon 9 rotor with specific rotation speed, the included angle of the optical axis relative to the rotation axis is fixed, so the measured change of the attitude angle of the optical axis is the change of the rotation axis.
As described above, the polarization state of the laser light of the microsphere 9 is circularly polarized, and the circularly polarized component of the polarization state of the outgoing light is reduced due to the phase retardation caused by the birefringent material microsphere 9, and the linear polarized component appears, i.e., the state of elliptical polarization (the state of superposition of linear polarization and circular polarization). For the test light path shown in fig. 1, that is, the polarizing beam splitter prism 15 added in front of the photodetector 16, the test result will reflect the attitude angle of the rotor optical axis of the microsphere 9 for different states of the microsphere 9. When the optical axis of the microsphere 9 is parallel to the laser propagation direction, the scattered light is not out of phase, and thus is still circularly polarized light. Since the intensity of circularly polarized light is uniform in any polarization direction, there is no change in the output on the photodetector 16. When the optical axis of the microsphere 9 forms a certain included angle theta with the laser propagation direction, the laser is in an elliptical polarization state due to the phase difference. It is decomposed into a circularly polarized component and a linearly polarized component, wherein the light intensity of the circularly polarized component is also uniform in all directions, so that the component acts on the photodetector 16 without an alternating signal output. For the linear polarization component, only the polarization direction component designated by the polarization beam splitter prism 15 can pass through after passing through the polarization beam splitter prism 15 (the polarization direction component is a preset fixed direction and is not adjusted according to the state of the microsphere 9), so that the light intensity acting on the photodetector 16 depends on the angle between the linear polarization component and the transmission polarization direction of the polarization beam splitter prism 15. Since the polarization direction of the linear polarization component is rotated with the rotation of the microsphere 9, the detection signal appears to be periodically changed, and the change amplitude is increased with the increase of the linear polarization component.
On the other hand, the larger the polarization component of the scattered light transmitted through the microspheres 9, the more circularly polarized light is converted into linearly polarized light. The spin angular momentum of the converted light is transferred to the microsphere 9 to form a driving moment, and the larger the linearly polarized light component is, the larger the driving moment is, the larger the rotating speed of the corresponding microsphere 9 is, and the change of the rotating speed of the microsphere 9 is further shown. Thus, by observing the change in the light intensity signal of the back-scattered light acting on the photodetector 16, the change in the attitude angle can be obtained, and the detection of angular movement can be realized.
In the testing process, the rotating speed information of the rotating signals is more sensitive to the response of the attitude angle, and the rotating speed is more convenient to measure. So when the pressure stabilizes, the rotation frequency will also reach a steady state, and the rotation speed can be used to measure the deflection angle caused by the input angular velocity, to ensure the sensitivity of the measurement. Since the rotational speed is also sensitive to the air pressure, the attitude angle is often measured by the amplitude information of the rotation signal during the pressure reduction.
The application relates to a use method of an optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection, which comprises the following steps:
step S1, turning on a laser light source 1 to vibrate a vibrating piece 10 so as to separate microspheres 9 from the vibrating piece 10, and capturing the microspheres 9;
step S2, adjusting a 1/4 wave plate 5 of the light modulation unit until the polarization state of laser is adjusted to be in a circularly polarized light state, and driving the microsphere 9 to rotate;
and S3, inputting the angular velocity, and detecting the laser power change after the polarizing beam splitter prism 15 by the photoelectric detector 16 of the detection unit to obtain the attitude angle information of the microsphere 9, thereby realizing the detection of the rotation signal of the microsphere 9.
In this embodiment, step A1 is further included between step S2 and step S3, where step A1 is: the vacuum pump in the vacuum cavity 6 is opened, the air pressure in the vacuum cavity 6 is reduced, the rotating speed of the microspheres 9 is increased to reach a first threshold value, the vacuum pump is closed, and the rotating speed of the microspheres 9 is stabilized.
Taking a rotor of microsphere 9 with a diameter of 4 μm as an example, the material of microsphere 9 is vaterite birefringent crystal, refractive indexes in the ordinary and extraordinary directions of the optical axis are 1.55 and 1.65, respectively, and ovality in shape is about 5%. Too much ovality results in unstable rotation of the particles of the microsphere 9, while too little ovality does not regulate the initial position of the optical axis, and in the present application, the preferred range of ovality may be between 3% and 20%.
The application method of the optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection of the embodiment comprises the following steps:
in the step P1, firstly, the microspheres 9 are placed on the glass sheet 101, then, a piezoelectric sheet vibration exciter is turned on to drive the glass sheet 101 to vibrate, and the microspheres 9 are thrown to the vicinity of a stable suspension position. Under the gradient force and scattering force of the suspending laser, the microsphere 9 near the capturing area will be stably suspended at the position where the light intensity is maximum, i.e. the central position where the laser is focused. To achieve stable suspension of the microspheres 9, the laser was strongly focused using a focusing objective lens 7 with a numerical aperture of 1.25, the power of the laser being about 20mW.
And P2, adjusting the 1/4 wave plate 5, observing the rotating speed of the microsphere 9 at the same time, and stopping adjusting when the rotating speed of the microsphere 9 reaches the maximum, wherein the laser is closest to the circular polarization state. In the atmosphere, the rotational speed of the microspheres 9 is about 40Hz. The vacuum pump for evacuating the vacuum chamber 6 is then turned on, and the air pressure in the vacuum chamber 6, that is, the air damping, is reduced, so that the rotation speed of the microspheres 9 is increased. When the air pressure was reduced to 8Pa, the rotational speed of the microspheres 9 was increased to 200kHz (first threshold). At this time, the vacuum valve is closed, and the air pressure in the cavity is kept stable, so that the rotation speed of the microsphere 9 is also stabilized.
And step P3, after the rotating speed of the rotor of the microsphere 9 is stable, recording the light intensity change rule of the back scattered light after passing through the polarization beam splitter prism 15 by utilizing the photoelectric detector 16, wherein the state corresponds to the attitude angle information of the microsphere 9 during zero input.
When the microsphere 9 rotates at a high speed, the angular velocity is input along the direction perpendicular to the rotation axis of the microsphere 9, and a gyroscopic moment is generated in the orthogonal direction of the angular velocity, and drives the rotation axis of the microsphere 9 rotor to deviate from the original position, so that the gyroscopic effect is realized by detecting the change of the attitude angle of the rotation axis of the microsphere 9. When the angular velocity is input, the rotation signal of the microsphere 9 is measured by the photoelectric detector 16, and the amplitude or the rotation speed change of the microsphere is extracted to be used as the output of the gyroscope.
The scattered light transmitted through the microsphere 9 is irradiated onto the photodetector 16 after passing through the polarization beam splitter prism 15, so that the change of the optical signal detected by the photodetector 16 is mainly a change of polarization information.
When the attitude angle of the microsphere 9 changes, the spatial position of the optical axis also changes. When the laser light passes through the birefringent crystal (microsphere 9), a retardation phase difference is generated in the ordinary and extraordinary directions, and the magnitude of the phase difference is correlated with the attitude angle of the optical axis. The closer the attitude angle of the optical axis of the microsphere 9 is to the perpendicular plane (90 degrees to the propagation direction) of the laser propagation direction, the larger the phase difference is. When the optical axis of the microsphere 9 is parallel to the propagation direction of the laser (the included angle between the optical axis and the propagation direction is 0 degrees), the microsphere 9 will not generate double refraction, and the phase difference is 0. Whereas for laser light, the phase difference of the ordinary and extraordinary rays is directly expressed as the polarization state of the laser light.
The polarization state of the laser light incident on the microsphere 9 is circularly polarized, and the circularly polarized component of the polarization state of the outgoing light is reduced with the increase of the phase delay, and a linear polarized component appears. The greater the polarization component of the scattered light transmitted through the microsphere 9, the more circularly polarized light is converted into linearly polarized light. The spin angular momentum of the converted light is transferred to the microsphere 9 to form a driving moment, and the larger the linearly polarized light component is, the larger the driving moment is, the larger the rotating speed of the corresponding microsphere 9 is, and the change of the rotating speed of the microsphere 9 is further shown. Therefore, by detecting the rotation speed change of the rotor of the microsphere 9, the change of the attitude angle information of the microsphere 9 can be corresponding, so that the angular motion measurement is realized.
In the experiment, the response of the microsphere 9 rotor to the input angular velocity can be obtained by pressing the air floatation platform (the whole device is arranged on the air floatation platform, and the platform is inclined to realize the input of the angular velocity when the air floatation platform is pressed) to input the angular velocity, and simultaneously recording the rotation speed change of the microsphere 9 rotor, as shown in fig. 5. The input angular speed of the air floatation platform is calibrated by a commercial gyroscope, and the output is the rotation speed change of the rotor of the microsphere 9. The output of the gyroscope changes along with the change of the angular velocity, the output of the gyroscope and the output of the gyroscope are approximately in linear relation, and R is linearly fitted 2 =0.94, with a better linear relationship.
The foregoing details of the optional implementation of the embodiment of the present application have been described in detail with reference to the accompanying drawings, but the embodiment of the present application is not limited to the specific details of the foregoing implementation, and various simple modifications may be made to the technical solution of the embodiment of the present application within the scope of the technical concept of the embodiment of the present application, and these simple modifications all fall within the protection scope of the embodiment of the present application.
Claims (8)
1. The utility model provides an optical suspension microballon rotor top based on optical axis attitude angle detects, includes laser light source (1), light modulation unit, the capture suspension unit, the detecting element that set gradually according to the laser light path order, the laser of laser light source (1) transmission is used for catching microballon (9) in the capture suspension unit after being adjusted by light modulation unit, the detecting element is used for detecting the attitude angle of microballon (9), its characterized in that:
the light modulation unit comprises a beam expander system (2), a dichroic mirror (4) and a 1/4 wave plate (5) which are arranged in sequence according to a laser light path, and is used for adjusting the polarization state of laser light into a circularly polarized light state;
the capturing suspension unit comprises a vacuum cavity (6), and a focusing objective lens (7), a vibrating piece (10) and an imaging objective lens (11) which are positioned in the vacuum cavity (6) and are arranged in sequence according to a laser light path, wherein the microsphere (9) is placed on the vibrating piece (10) capable of vibrating, and when the vibrating piece (10) vibrates, the microsphere (9) can be thrown and suspended above the vibrating piece (10), and the microsphere (9) is prepared by adopting a birefringent crystal material;
the detection unit comprises a polarization beam splitting prism (15), a photoelectric detector (16) and a data acquisition device (17) which are arranged in sequence according to a laser light path, wherein the data acquisition device is electrically connected with the photoelectric detector (16);
the light suspension microsphere rotor gyroscope further comprises a light filter (12) and a reflecting mirror (14) which are arranged in sequence of a laser light path, wherein the light filter (12) is positioned between the image capturing device (13) and the vacuum cavity (6), and the reflecting mirror (14) is positioned between the polarization beam splitting prism (15) and the light filter (12);
the microsphere (9) is in an ellipsoidal shape;
the light suspension microsphere rotor gyroscope utilizes a beam of laser to realize suspension, driving and signal detection of the microsphere rotor.
2. The light suspension microsphere rotor gyroscope of claim 1, wherein: the light suspension microsphere rotor gyroscope further comprises an observation unit, wherein the observation unit comprises a visible light source (3) and an image capturing device (13), and the visible light source (3) and the image capturing device (13) are respectively positioned at the front end of a laser inlet and the rear end of a laser outlet of the vacuum cavity (6).
3. The light suspension microsphere rotor gyroscope of claim 2, wherein: the dichroic mirror (4) and the 1/4 wave plate (5) are arranged between the visible light source (3) and the laser inlet front end of the vacuum cavity (6).
4. The light suspension microsphere rotor gyroscope of claim 1, wherein: the beam expander system (2) comprises two beam expanders (21), and the convex surfaces of the beam expanders (21) are arranged in opposite directions.
5. The light suspension microsphere rotor gyroscope of claim 1, wherein: the birefringent crystal material is one of vaterite, calcite and quartz crystal material.
6. The light suspension microsphere rotor gyroscope of claim 1, wherein: the image capturing device (13) is arranged at the back focal length of the imaging objective lens (11).
7. The light suspension microsphere rotor gyroscope of claim 1, wherein: the vibration piece (10) comprises a glass sheet (101) and a piezoelectric sheet (102), wherein the microspheres (9) are positioned on the glass sheet (101), the piezoelectric sheet (102) is connected with the glass sheet (101), and the thickness of the glass sheet (101) is matched with the focal length of the focusing objective lens (7).
8. A method of using an optical suspension microsphere rotor gyroscope according to any one of claims 1 to 7, characterized in that: the method comprises the following steps:
step S1, a laser light source (1) is turned on to vibrate a vibrating piece (10) so that the microspheres (9) are separated from the vibrating piece (10), and the microspheres (9) are captured;
s2, adjusting a 1/4 wave plate (5) of the light modulation unit until the polarization state of laser is adjusted to be in a circularly polarized light state, and driving the microsphere (9) to rotate;
s3, inputting angular velocity, detecting laser power change after a polarization beam splitting prism (15) by a photoelectric detector (16) of a detection unit to obtain attitude angle information of the microsphere (9), and detecting a rotation signal of the microsphere (9);
in the step S3, the direction of change of the attitude angle information is perpendicular to the measured angular velocity Ω, and the size of the attitude angle is Ω H/k, where H is the angular momentum of the microsphere (9), and k is the stiffness of the optical torque spring.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310715456.5A CN116448086B (en) | 2023-06-16 | 2023-06-16 | Optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310715456.5A CN116448086B (en) | 2023-06-16 | 2023-06-16 | Optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116448086A CN116448086A (en) | 2023-07-18 |
| CN116448086B true CN116448086B (en) | 2023-09-12 |
Family
ID=87128869
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310715456.5A Active CN116448086B (en) | 2023-06-16 | 2023-06-16 | Optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116448086B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2060503A1 (en) * | 1969-12-15 | 1971-06-24 | Western Electric Co | Device for capturing and accelerating neutral particles |
| CN104034322A (en) * | 2014-06-19 | 2014-09-10 | 浙江大学 | Device for measuring angular speed through optical suspension rotor microgyroscope |
| CN110514191A (en) * | 2019-10-22 | 2019-11-29 | 中国人民解放军国防科技大学 | Micro-computer electro-optical suspension rotary microparticle gyroscope |
| CN112635094A (en) * | 2021-03-11 | 2021-04-09 | 中国人民解放军国防科技大学 | Chip-type microparticle optical suspension device and microparticle capturing method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7746475B2 (en) * | 2007-10-09 | 2010-06-29 | Samsung Electronics Co., Ltd. | Microgyroscope |
| US10866099B1 (en) * | 2019-05-31 | 2020-12-15 | United States Of America As Represented By The Secretary Of The Navy | Electro-opto-mechanical micro gyroscope |
-
2023
- 2023-06-16 CN CN202310715456.5A patent/CN116448086B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2060503A1 (en) * | 1969-12-15 | 1971-06-24 | Western Electric Co | Device for capturing and accelerating neutral particles |
| CN104034322A (en) * | 2014-06-19 | 2014-09-10 | 浙江大学 | Device for measuring angular speed through optical suspension rotor microgyroscope |
| CN110514191A (en) * | 2019-10-22 | 2019-11-29 | 中国人民解放军国防科技大学 | Micro-computer electro-optical suspension rotary microparticle gyroscope |
| CN112635094A (en) * | 2021-03-11 | 2021-04-09 | 中国人民解放军国防科技大学 | Chip-type microparticle optical suspension device and microparticle capturing method |
Non-Patent Citations (1)
| Title |
|---|
| Research on a MEMS Microparticles Vacuum Chamber for Optical Levitation with a Built-In Vacuum Gauge;Junji Pu et.al;Photonics;1-15 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116448086A (en) | 2023-07-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112485163A (en) | Device and method for feeding back cooling particles in double-beam optical trap | |
| US10157692B2 (en) | Cold atom interferometry | |
| JP5161440B2 (en) | Vibrating beam gyroscope, driving method of vibrating beam gyroscope | |
| JP2010286477A (en) | Gyroscope and rotation detection method | |
| US20230243998A1 (en) | Absolute gravimeter and measurement method based on vacuum optical tweezers | |
| WO2016206152A1 (en) | Mems vibratory gyroscope having single anchor point and four mass block | |
| WO2019040817A2 (en) | Cold atom interferometry | |
| US6325172B1 (en) | Geophone including laser interferometer | |
| JP7381816B2 (en) | Optical levitation angular velocity measurement device and method based on the geometric phase of solid-state atomic spins | |
| CN113514179B (en) | Force field gradient measuring device and method based on double-vibrator suspension optomechanics system | |
| CN104655154A (en) | Static balance testing device and method of high-precision gyroscope suspension system | |
| JP2018132500A (en) | Acceleration meter using microparticles | |
| CN116448086B (en) | Optical suspension microsphere rotor gyroscope based on optical axis attitude angle detection | |
| CN115840257A (en) | Device and method for measuring relative gravity acceleration | |
| CN109059892B (en) | Photon suspension gyroscope based on double-beam optical trap system | |
| CN210199398U (en) | Control device for light trapping particles | |
| US9500766B2 (en) | Interferometric gravimeter apparatus and method | |
| CN102621348A (en) | Optical fiber accelerometer based on silicon micromachining technology | |
| CN102650525A (en) | Method for calibrating resolution of photoelectric sensor of electrostatic gyro polar axis | |
| CN110514191A (en) | Micro-computer electro-optical suspension rotary microparticle gyroscope | |
| CN111855505B (en) | Microsphere cluster state detection device and detection method applied to vacuum optical trap system | |
| Zeng et al. | Optically levitated gyroscopes with a MHz rotating micro-rotor | |
| CN113406715A (en) | Absolute gravimeter falling body error measuring device | |
| CN113701998A (en) | Focusing lens arrangement error correction device and method in optical tweezers system | |
| CN104034322B (en) | Optical levitation rotor micro gyro measures the device of angular velocity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |