Fiber optic gyroscope with stress compensation

Abstract

The present application relates to a fiber optic gyroscope with stress compensation. In addition to the existing fiber optic gyroscope comprising a light source, a coupler, a Y-waveguide, a fiber optic ring, a detector, and a signal processing circuit, a temperature sensor and a piezoelectric ceramic are added. The coupler is connected to the light source, the detector, and the Y-waveguide, respectively; and the signal control circuit is connected to the detector, the temperature sensor, the Y-waveguide, and the piezoelectric ceramic, respectively. Since the fiber optic ring is wound with a first optical fiber and a second optical fiber, the Y-waveguide and the fiber optic ring are connected via a first optical fiber pigtail and a second optical fiber pigtail, and the first optical fiber pigtail or the second optical fiber pigtail is also wound around the piezoelectric ceramic. During operation, the signal processing circuit controls the piezoelectric ceramic in real time to perform pressure compensation on the first optical fiber pigtail or the second optical fiber pigtail wound around the piezoelectric ceramic based on the sensitive angular velocity information and temperature information of the fiber optic gyroscope, thereby balancing the stress values ​​on both sides and thereby compensating for the zero drift of the fiber optic gyroscope caused by stress.

Description

Technical Field

[0001] The present application relates to the technical field of angular rate sensors, and in particular to a fiber optic gyroscope with stress compensation. Background Art

[0002] Fiber optic ring fabrication typically begins at the midpoint of a single fiber and is wound in both clockwise and counterclockwise directions. This process inevitably introduces additional stress interference, resulting in asymmetric stress within the fibers on both sides. Furthermore, as the number of winding layers increases, the bending radius also increases, causing the average stress within each layer to vary. After the fiber optic ring is wound, it needs to be filled with potting compound and cured. This curing process also introduces stress interference. Consequently, after the fiber optic ring is fabricated, the stresses on the two fibers, which are symmetrical about the midpoint, deviate. This deviation also changes with ambient temperature, causing the zero position of the fiber optic gyroscope to drift and severely lose accuracy. Summary of the Invention

[0003] In order to at least overcome the problems existing in the related art to a certain extent, the present application provides a fiber optic gyroscope with stress compensation.

[0004] The scheme of this application is as follows:

[0005] A fiber optic gyroscope with stress compensation, characterized by comprising:

[0006] Light source, coupler, Y waveguide, optical fiber ring, detector, temperature sensor, signal processing circuit, piezoelectric ceramics;

[0007] The coupler is respectively connected to the light source, the detector and the Y waveguide;

[0008] The signal control circuit is respectively connected to the detector, the temperature sensor, the Y waveguide and the piezoelectric ceramic;

[0009] The optical fiber ring is wound with a first optical fiber and a second optical fiber;

[0010] The Y-waveguide and the optical fiber ring are connected via a first optical fiber pigtail and a second optical fiber pigtail;

[0011] The first optical fiber pigtail or the second optical fiber pigtail is further wound on the piezoelectric ceramic;

[0012] The detector is used to detect sensitive angular rate information of the fiber optic gyroscope and send it to the signal processing circuit;

[0013] The temperature sensor is used to detect the temperature information of the fiber optic gyroscope and send it to the signal processing circuit;

[0014] The signal processing circuit is used to control the piezoelectric ceramic to perform stress compensation on the first optical fiber pigtail or the second optical fiber pigtail wound on the piezoelectric ceramic according to the sensitive angular rate information and the temperature information.

[0015] Preferably, in one achievable method of the present application,

[0016] The signal processing circuit controls the magnitude of the current on the piezoelectric ceramic and performs stress compensation on the first optical fiber pigtail or the second optical fiber pigtail wound on the piezoelectric ceramic.

[0017] Preferably, in one achievable method of the present application,

[0018] The first optical fiber and the second optical fiber are wound around the optical fiber ring in opposite directions.

[0019] Preferably, in one achievable method of the present application,

[0020] The signal processing circuit includes: a signal control circuit and a stress control circuit;

[0021] The signal control circuit is respectively connected to the detector, the temperature sensor, the Y waveguide and the stress control circuit;

[0022] The stress control circuit is connected to the piezoelectric ceramic.

[0023] Preferably, in one achievable manner of the present application, the optical fiber pigtail wound around the piezoelectric ceramic is the optical fiber pigtail with the least stress among the first optical fiber and the second optical fiber.

[0024] Preferably, in an achievable manner of the present application, the winding length of the first optical fiber pigtail or the second optical fiber pigtail on the piezoelectric ceramic is 50 cm-100 cm.

[0025] Preferably, in an achievable manner of the present application, the winding length of the first optical fiber pigtail or the second optical fiber pigtail on the piezoelectric ceramic is determined by the stress deviation of the first optical fiber and the second optical fiber.

[0026] Preferably, in one achievable method of the present application,

[0027] The first optical fiber and the second optical fiber are wound on the optical fiber ring in a quadrupole symmetric manner.

[0028] Preferably, in one achievable method of the present application,

[0029] The winding tension of the first optical fiber and the second optical fiber is 5g-10g.

[0030] Preferably, in one achievable method of the present application,

[0031] The piezoelectric ceramic is a ring structure.

[0032] The technical solution provided by this application may have the following beneficial effects:

[0033] The fiber optic gyroscope with stress compensation in the present application is based on the existing fiber optic gyroscope including a light source, a coupler, a Y-waveguide, a fiber ring, a detector and a signal processing circuit, and adds a temperature sensor and a piezoelectric ceramic. Among them, the coupler is respectively connected to the light source, the detector and the Y-waveguide; the signal control circuit is respectively connected to the detector, the temperature sensor, the Y-waveguide and the piezoelectric ceramic. Since the fiber ring is wound with a first optical fiber and a second optical fiber, the Y-waveguide and the fiber ring are connected through a first optical fiber pigtail and a second optical fiber pigtail, and the first optical fiber pigtail or the second optical fiber pigtail is also wound on the piezoelectric ceramic. During operation, the detector detects the sensitive angular velocity information of the fiber optic gyroscope and sends it to the signal processing circuit, the temperature sensor detects the temperature information of the fiber optic gyroscope and sends it to the signal processing circuit, and the signal processing circuit controls the piezoelectric ceramic in real time according to the sensitive angular velocity information and temperature information of the fiber optic gyroscope to perform pressure compensation on the first optical fiber pigtail or the second optical fiber pigtail wound on the piezoelectric ceramic, balances the stress values ​​on both sides, and thus compensates for the zero drift of the fiber optic gyroscope caused by stress.

[0034] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0036] Figure 1 This is a schematic structural diagram of a fiber optic gyroscope with stress compensation provided by an embodiment of the present application;

[0037] Figure 2 This is a schematic structural diagram of a fiber optic gyroscope with stress compensation provided in another embodiment of the present application.

[0038] Reference numerals: light source 1 ; coupler 2 ; Y-waveguide 3 ; optical fiber ring 4 ; detector 5 ; signal processing circuit 6 ; signal control circuit 61 ; temperature control circuit 62 ; piezoelectric ceramic 7 ; temperature sensor 8 . DETAILED DESCRIPTION

[0039] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0040] Figure 1 This is a schematic diagram of the structure of a fiber optic gyroscope with stress compensation provided by an embodiment of the present application, with reference to Figure 1 , a fiber optic gyroscope with stress compensation, comprising:

[0041] Light source 1, coupler 2, Y waveguide 3, optical fiber ring 4, detector 5, temperature sensor 8, signal processing circuit 6 and piezoelectric ceramic 7;

[0042] The coupler 2 is connected to the light source 1, the detector 5 and the Y waveguide 3 respectively;

[0043] The signal control circuit 61 is respectively connected to the detector 5, the temperature sensor 8, the Y waveguide 3 and the piezoelectric ceramic 7;

[0044] The optical fiber ring 4 is wound with a first optical fiber and a second optical fiber;

[0045] The Y-waveguide 3 and the optical fiber ring 4 are connected by a first optical fiber pigtail and a second optical fiber pigtail;

[0046] The first optical fiber pigtail or the second optical fiber pigtail is further wound on the piezoelectric ceramic 8;

[0047] The detector 5 is used to detect the sensitive angular rate information of the fiber optic gyroscope and send it to the signal processing circuit 6;

[0048] The temperature sensor 8 is used to detect the temperature information of the fiber optic gyroscope and send it to the signal processing circuit 6;

[0049] The signal processing circuit 6 is used to control the piezoelectric ceramic 7 to perform stress compensation on the first optical fiber pigtail or the second optical fiber pigtail wound on the piezoelectric ceramic 8 according to the sensitive angular rate information and the temperature information.

[0050] In the fiber optic ring 4 manufacturing technology, the optical fiber needs to be wound around the fiber optic ring 4 skeleton according to a specific winding method. According to the working principle of the fiber optic ring 4, the optical signal generated by the light source 1 is input separately by the two ends of the optical fiber. To minimize the external disturbances on the optical signal, the optical signals are synchronously input into the optical fiber, and they travel the same optical path and are subjected to the same external disturbances at the same time. In this way, the errors introduced by external factors can be eliminated when the two beams of light return and interfere, thereby ensuring the accuracy of the fiber optic gyroscope.

[0051] The optical fiber pigtail refers to the remaining portion after the first optical fiber and the second optical fiber are wound around the optical fiber ring 4 .

[0052] Preferably, in this embodiment, the first optical fiber and the second optical fiber are wound on the optical fiber ring 4 in a quadrupole symmetrical manner, thereby eliminating temperature-induced phase errors to a great extent.

[0053] The fiber optic ring 4 is wound in a quadrupole symmetrical manner and then potted and cured. During the fiber optic ring winding process, stress fluctuations caused by imperfect winding equipment are inevitable. Preferably, a tension of 5-10g is generally used for winding. The tension is ultimately reflected in different stress distribution effects inside the optical fiber. There will be tension fluctuations at the winding turn, layer change, and edge locations, resulting in abnormal stress. As the number of winding layers increases, the stress at different winding radii will also be inconsistent. On the other hand, during the potting process, curing stress and vacuum treatment stress will be introduced. This asymmetric stress distribution inside the fiber optic ring will affect the fiber optic ring 4 and produce phase error. The fiber optic gyroscope error effect caused by stress can be expressed as:

[0054]

[0055] Where Ω is the zero drift of the gyroscope, n is the refractive index of the fiber, λ is the wavelength of light, c0 is the speed of light in a vacuum, β0 is the propagation constant of light, ΔS(z) represents the stress change at point z of the fiber sensing loop, L is the fiber length, and D is the loop diameter.

[0056] It can be seen from the formula that if stress symmetry exists between two points symmetrical about the midpoint, the optical fiber ring 4 will eventually generate an error in the detection angular rate signal.

[0057] In particular, when environmental factors change, such as temperature, the stress inside the optical fiber ring 4 also changes, thereby affecting the stability of the overall performance of the optical fiber gyroscope.

[0058] A fiber optic gyroscope generally consists of a light source 1, a coupler 2, a Y-waveguide 3, a fiber ring 4, a detector 5, and a processing circuit. After the fiber ring 4 is wound, its internal stress distribution is fixed accordingly. This stress changes with temperature, causing the fiber optic gyroscope to also experience zero-position drift with temperature changes.

[0059] The first optical fiber and the second optical fiber are wound around the optical fiber ring in opposite directions. For example, the first optical fiber is wound around the optical fiber ring 4 in a clockwise direction, and the second optical fiber is wound around the optical fiber ring 4 in a counterclockwise direction.

[0060] In this embodiment, first, a stress analyzer is used to test different optical fiber rings 4 through simulation calculation to obtain a stress distribution curve inside the optical fiber ring 4; the optical fiber ring 4 is placed in a temperature box to test the stress distribution curve under a temperature change environment.

[0061] Since the first optical fiber and the second optical fiber may be of different lengths, a certain stress integral difference will be generated between the first optical fiber and the second optical fiber.

[0062] According to the test results, the stress integral difference on both sides of the optical fiber ring 4 and the curve of its change with temperature are calculated.

[0063] The optical fiber pigtail with less stress is wound around the piezoelectric ceramic 7 .

[0064] Preferably, the piezoelectric ceramic 7 is a ring structure, which is easier to wind.

[0065] The winding length of the first optical fiber pigtail or the second optical fiber pigtail on the piezoelectric ceramic 7 is 50 cm-100 cm, and the winding length is determined by the stress deviation of the first optical fiber and the second optical fiber.

[0066] Combined with the stress analyzer test, the effect of stress applied by piezoelectric ceramics is obtained, and the control parameters equal to the stress difference of the optical fiber ring are found.

[0067] The method of controlling the stress of the optical fiber by the piezoelectric ceramic 7 is used to fit the stress variation curve of the optical fiber ring 4 under temperature variation conditions, and the control parameters of the piezoelectric ceramic 7 under different temperature conditions are obtained.

[0068] When the fiber optic gyroscope is working, the fiber ring 4 generates stress due to temperature, resulting in zero drift. The detector 5 detects the temperature value of the fiber optic gyroscope and sends it to the signal processing circuit 6. The signal processing circuit 6 obtains the temperature value of the fiber optic gyroscope, and controls the current on the piezoelectric ceramic 7 in real time according to the gyro output value and the temperature value. The current is regulated according to the pre-fitted temperature and current correspondence, balancing the stress values ​​on both sides, thereby compensating for the zero drift of the fiber optic gyroscope caused by stress.

[0069] The gyro output value is calculated by the signal processing circuit based on the sensitive angular rate information of the fiber optic gyroscope detected by the detector.

[0070] The temperature value is obtained based on the temperature information detected by the temperature sensor.

[0071] In some embodiments, the fiber optic gyroscope with stress compensation is described with reference to Figure 2 ,

[0072] The signal processing circuit 6 includes: a signal control circuit 61 and a temperature control circuit 62;

[0073] The signal control circuit 61 is respectively connected to the detector 5, the temperature sensor 8, the Y waveguide 3 and the temperature control circuit 62;

[0074] The temperature control circuit 62 is connected to the piezoelectric ceramic 7 .

[0075] The signal control circuit 61 is mainly used to receive the sensitive angular rate information sent by the detector 5 and the temperature information sent by the temperature sensor 8, and calculate the temperature value that needs to be controlled based on the sensitive angular rate information and temperature information of the fiber optic gyroscope. The temperature control circuit 62 is mainly used to control the piezoelectric ceramic 7 to perform stress compensation on the first optical fiber pigtail or the second optical fiber pigtail wound on the piezoelectric ceramic 7.

[0076] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0077] It should be noted that, in the description of this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0078] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0079] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0080] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0081] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0082] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0083] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0084] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A fiber optic gyroscope with stress compensation, characterized in that: include: Light source, coupler, Y waveguide, optical fiber ring, detector, temperature sensor, signal processing circuit, piezoelectric ceramics; The signal processing circuit includes: a signal control circuit and a stress control circuit; The signal control circuit is respectively connected to the detector, the temperature sensor, the Y waveguide and the stress control circuit; The stress control circuit is connected to the piezoelectric ceramic; The coupler is respectively connected to the light source, the detector and the Y waveguide; The signal control circuit is respectively connected to the detector, the temperature sensor, the Y waveguide and the piezoelectric ceramic; The optical fiber ring is wound with a first optical fiber and a second optical fiber; The Y-waveguide and the optical fiber ring are connected via a first optical fiber pigtail and a second optical fiber pigtail; The first optical fiber pigtail or the second optical fiber pigtail is further wound on the piezoelectric ceramic; The detector is used to detect sensitive angular rate information of the fiber optic gyroscope and send it to the signal processing circuit; The temperature sensor is used to detect the temperature information of the fiber optic gyroscope and send it to the signal processing circuit; The signal processing circuit is used to control the piezoelectric ceramic to perform stress compensation on the first optical fiber pigtail or the second optical fiber pigtail wound on the piezoelectric ceramic according to the gyroscope output value and the temperature information, so as to balance the stress values ​​on both sides; The optical fiber pigtail wound around the piezoelectric ceramic is the optical fiber pigtail with the smallest stress among the first optical fiber and the second optical fiber.

2. The optical fiber gyroscope with stress compensation according to claim 1, wherein: The signal processing circuit controls the magnitude of the current on the piezoelectric ceramic and performs stress compensation on the first optical fiber pigtail or the second optical fiber pigtail wound on the piezoelectric ceramic.

3. The optical fiber gyroscope with stress compensation according to claim 1, wherein: The first optical fiber and the second optical fiber are wound around the optical fiber ring in opposite directions.

4. The optical fiber gyroscope with stress compensation according to claim 1, wherein: The winding length of the first optical fiber pigtail or the second optical fiber pigtail on the piezoelectric ceramic is 50 cm-100 cm.

5. The optical fiber gyroscope with stress compensation according to claim 4, characterized in that: The winding length of the first optical fiber pigtail or the second optical fiber pigtail on the piezoelectric ceramic is determined by the stress deviation of the first optical fiber and the second optical fiber.

6. The optical fiber gyroscope with stress compensation according to claim 1, wherein: The first optical fiber and the second optical fiber are wound on the optical fiber ring in a quadrupole symmetric manner.

7. The optical fiber gyroscope with stress compensation according to claim 1, wherein: The winding tension of the first optical fiber and the second optical fiber is 5g-10g.

8. The optical fiber gyroscope with stress compensation according to claim 1, wherein: The piezoelectric ceramic is a ring structure.

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