A resonant fiber optic gyroscope with large dynamic range

Abstract

The present invention discloses a large dynamic range resonant fiber optic gyroscope, belonging to the technical field of optical sensing. It solves the problem that current optical gyroscopes have a small dynamic range and are non-adjustable, making it difficult to meet the needs of places with a large range of rotational speed variations, and that the direction of rotational speed can only be determined by phase modulation of light. The invention comprises first and second voltage signal sources, a laser, a polarization controller, a fiber coupler, a fiber ring, a piezoelectric ceramic tube, a detector, and a signal processing and control system. The invention utilizes the piezoelectric ceramic tube to control the cavity length of the fiber resonant cavity, thereby achieving a large dynamic range. At the same time, a narrow linewidth laser is utilized to output continuous, constant-intensity, frequency-tunable narrow linewidth laser light to obtain the transmission spectrum of the fiber resonant cavity. By accurately locating the resonant frequency, the magnitude and direction of the rotational speed can be simultaneously determined. The invention has the advantages of a large dynamic range, a large rotation rate measurement range, and the ability to determine the direction of rotational speed without phase modulation of light.

Description

Technical Field

[0001] The present invention relates to the technical field of optical sensing, and in particular to a large dynamic range resonant fiber optic gyroscope. Background Art

[0002] In 1976, V. Vali and RW Shorthill of the University of Utah successfully developed the first fiber optic gyroscope. The fiber optic gyroscope has the advantages of no mechanical moving parts, no warm-up time, insensitivity to acceleration, digital output, small size, and low cost. In addition, the fiber optic gyroscope overcomes the fatal shortcomings of the laser gyroscope, such as the locking phenomenon. Therefore, the fiber optic gyroscope attracted the attention of many universities and research institutions in the world as soon as it came out, and it has developed rapidly.

[0003] Current resonant fiber gyros (RFGs) use a fiber resonator made of a single-mode fiber. As the gyro rotates, the resonant frequency of the fiber resonator changes with the angular velocity of the rotation. Therefore, by detecting changes in the resonant frequency of the fiber resonator, the angular velocity of the rotation can be measured. However, current RFGs have a small and fixed dynamic range, making them difficult to meet the needs of environments with a wide range of rotational speed variations. Furthermore, current RFGs contain a phase modulator, which modulates light by applying a voltage signal to the phase modulator to determine the direction of rotational speed. This method of determining the direction of rotational speed increases the complexity of the gyro system, introduces corresponding noise, and reduces sensing accuracy. Summary of the Invention

[0004] Based on the above shortcomings, the present invention provides a large dynamic range resonant fiber gyroscope, which solves the problems of the current resonant fiber gyroscope, such as small dynamic range, fixed dynamic range, difficulty in meeting the needs of places with a large range of rotation speed changes, and the need to phase modulate the light to distinguish the direction of the rotation speed.

[0005] The objective of the present invention is achieved as follows: a large dynamic range resonant fiber gyroscope, comprising a first voltage signal source, a laser, a polarization controller, a fiber coupler, a fiber ring, a piezoelectric ceramic tube, a second voltage signal source, a detector, and a signal processing and control system; wherein the first signal output end of the first voltage signal source is connected to the modulation signal input end of the laser, the second signal output end of the first voltage signal source is connected to the first signal input end of the signal processing and control system, the optical output end of the laser is connected to the optical input end of the polarization controller, the optical output end of the polarization controller is connected to the first optical input end of the fiber coupler, the fiber ring is respectively connected to the second optical input end and the second optical output end of the fiber coupler, the fiber ring is wound around and fixed on the outer surface of the piezoelectric ceramic tube, the fiber coupler is a 2×2 fiber coupler, the signal output end of the second voltage signal source is connected to the signal input end of the piezoelectric ceramic tube, the signal input end of the second voltage signal source is connected to the first signal output end of the signal processing and control system, the first optical output end of the fiber coupler is connected to the optical input end of the detector, the signal output end of the detector is connected to the second signal input end of the signal processing and control system, and the second signal output end of the signal processing and control system outputs the gyroscope output signal;

[0006] The fiber coupler and fiber ring constitute a fiber resonant cavity; the laser outputs continuous, constant-intensity, frequency-tunable narrow-linewidth laser light, the linewidth of the laser light being smaller than the linewidth of the transmission valley of the fiber resonant cavity, and the frequency of the laser light corresponding to the voltage at the modulation signal input end of the laser; the greater the voltage, the greater the laser frequency, and the smaller the voltage, the smaller the laser frequency; the first signal output end and the second signal output end of the first voltage signal source output the same periodic triangular wave voltage signal, the maximum voltage of this periodic triangular wave voltage signal being U2 and the minimum voltage being U1. This periodic triangular wave voltage signal is applied to the modulation signal input end of the laser, so that the frequency tuning range of the laser light output by the laser light is equal to the free spectral width of the fiber resonant cavity when it is stationary;

[0007] The outer diameter of the piezoelectric ceramic tube changes in accordance with the voltage at its signal input end; the smaller the voltage, the larger the outer diameter of the piezoelectric ceramic tube, and the larger the voltage, the smaller the outer diameter of the piezoelectric ceramic tube;

[0008] The signal output end of the second voltage signal source outputs a DC voltage signal, and the DC voltage signal is applied to the signal input end of the piezoelectric ceramic tube to control the outer diameter of the piezoelectric ceramic tube;

[0009] When the fiber optic gyroscope is working, the signal processing and control system outputs a control signal and sends it to the second voltage signal source, so that the voltage value output by the second voltage signal source is 0; then, the first voltage signal source outputs a triangular wave voltage signal with a period of T and sends it to the signal processing and control system, and the triangular wave voltage signal is loaded into the modulation signal input end of the laser. At the same time, the transmission spectrum of the optical fiber resonant cavity with a period of T is detected by the detector, and the transmission spectrum signal output by the detector enters the signal processing and control system; then, the signal processing and control system obtains the triangular wave voltage signal and the transmission spectrum signal. If there is no transmission valley in the transmission spectrum signal, the signal processing and control system outputs a control signal and sends it to the second voltage signal source, so that the voltage value of the DC voltage signal output by the second voltage signal source gradually increases, thereby gradually reducing the outer diameter of the piezoelectric ceramic tube and the radius of the optical fiber ring until a transmission valley appears in the transmission spectrum signal; then, the signal processing and control system compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the triangular wave voltage signal, and generates a signal signal. The signal processing and control system compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the minimum voltage U1 of the triangular wave voltage signal as the time origin, and reads the time corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal. If the time t1 is greater than the time t0, the rotation speed direction is clockwise, and if the time t1 is less than the time t0, the rotation speed direction is counterclockwise, and the rotation speed magnitude is obtained by the absolute value of the difference between the time t1 and the time t0. Wherein, the time t0 is the voltage minimum U1 of the triangular wave voltage signal with a period of T output by the first voltage signal source of the optical fiber gyroscope under static conditions. The signal processing and control system compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the voltage minimum U1 of the triangular wave voltage signal as the time origin, and reads the time corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal. Finally, the signal processing and control system outputs a gyro output signal, and the gyro output signal includes the magnitude and direction of the rotation speed.

[0010] Furthermore, the signal processing and control system includes a sampling filtering circuit and a comparison output circuit; the first signal input end of the sampling filtering circuit is the first signal input end of the signal processing and control system, the second signal input end of the sampling filtering circuit is the second signal input end of the signal processing and control system, the first signal output end of the comparison output circuit is the first signal output end of the signal processing and control system, and the second signal output end of the comparison output circuit is the second signal output end of the signal processing and control system; the second signal output end of the first voltage signal source is connected to the first signal input end of the sampling filtering circuit, the signal output end of the detector is connected to the second signal input end of the sampling filtering circuit, the first signal output end of the sampling filtering circuit is connected to the first signal input end of the comparison output circuit, the second signal output end of the sampling filtering circuit is connected to the second signal input end of the comparison output circuit, the first signal output end of the comparison output circuit is connected to the signal input end of the second voltage signal source, and the second signal output end of the comparison output circuit outputs the gyroscope output signal.

[0011] Furthermore, when the fiber optic gyroscope is working, the comparison output circuit outputs a control signal 1 which is sent to the second voltage signal source, so that the voltage value output by the second voltage signal source is 0; then, the sampling and filtering circuit samples the triangular wave voltage signal with a period of T output by the first voltage signal source, and sends the triangular wave voltage signal to the comparison output circuit. At the same time, the sampling and filtering circuit samples the transmission spectrum signal with a period of T output by the detector, filters the transmission spectrum signal, and sends it to the comparison output circuit; after the comparison output circuit obtains the triangular wave voltage signal and the transmission spectrum signal, if there is no transmission valley in the transmission spectrum signal, the comparison output circuit outputs a control signal 2 which is sent to the second voltage signal source, so that the voltage value of the DC voltage signal output by the second voltage signal source gradually increases, thereby causing the piezoelectric ceramic tube to The outer diameter and the radius of the optical fiber ring gradually decrease until a transmission valley appears in the transmission spectrum signal; then, the comparison output circuit compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same cycle of the triangular wave voltage signal and the transmission spectrum signal, takes the moment corresponding to the minimum voltage value U1 of the triangular wave voltage signal as the time origin, reads the moment t1 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal, if the moment t1 is greater than the moment t0, the rotation speed direction is clockwise, if the moment t1 is less than the moment t0, the rotation speed direction is counterclockwise, and the rotation speed magnitude is obtained from the absolute value of the difference between the moment t1 and the moment t0; finally, the comparison output circuit outputs a gyroscope output signal, and the gyroscope output signal includes the rotation speed magnitude and direction.

[0012] Furthermore, before use, the fiber optic gyroscope needs to be "zeroed" under static conditions. The "zeroing" method is as follows: the comparison output circuit outputs a control signal 1 and sends it to the second voltage signal source, so that the voltage value output by the second voltage signal source is 0; then, the sampling and filtering circuit samples the triangular wave voltage signal with a period of T output by the first voltage signal source, and sends the triangular wave voltage signal to the comparison output circuit. At the same time, the sampling and filtering circuit samples the transmission spectrum signal with a period of T output by the detector, filters the transmission spectrum signal, and sends it to the comparison output circuit; after the comparison output circuit obtains the triangular wave voltage signal and the transmission spectrum signal, it compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the minimum voltage value U1 of the triangular wave voltage signal as the time origin, and reads the time t0 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal.

[0013] The beneficial effects and advantages of the present invention are as follows: the present invention utilizes a piezoelectric ceramic tube to control the cavity length of the optical fiber resonant cavity, thereby obtaining a large dynamic range. At the same time, a narrow-linewidth laser is utilized to output continuous, constant-intensity, frequency-tunable narrow-linewidth laser light to obtain the transmission spectrum of the optical fiber resonant cavity. Then, by precisely positioning the resonant frequency, the magnitude and direction of the rotation speed can be simultaneously obtained. The present invention has the advantages of a large dynamic range, a large range for measuring rotation rates, does not contain a phase modulation device, and can distinguish the direction of the rotation speed without performing phase modulation on the light. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention,

[0015] Figure 2 yes Figure 1 The voltage waveform diagram of the periodic triangular wave voltage signal output by the first voltage signal source is shown in FIG.

[0016] Figure 3 yes Figure 1 Schematic diagram of the optical fiber ring 5 being wound around and fixed on the outer surface of the piezoelectric ceramic tube,

[0017] Figure 4 yes Figure 1 Schematic diagram of the circuit structure of the signal processing and control system. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings:

[0019] Example 1

[0020] like Figure 1As shown, a large dynamic range resonant fiber gyroscope includes a first voltage signal source 1, a laser 2, a polarization controller 3, a fiber coupler 4, a fiber ring 5, a piezoelectric ceramic tube 6, a second voltage signal source 7, a detector 8 and a signal processing and control system 9; the first signal output end of the first voltage signal source 1 is connected to the modulation signal input end of the laser 2, the second signal output end of the first voltage signal source 1 is connected to the first signal input end of the signal processing and control system 9, the light output end of the laser 2 is connected to the light input end of the polarization controller 3, the light output end of the polarization controller 3 is connected to the first light input end of the fiber coupler 4, the fiber ring 5 is connected to the second light input end and the second light output end of the fiber coupler 4, the fiber ring 5 is wound around and fixed on the outer surface of the piezoelectric ceramic tube 6, the signal output end of the second voltage signal source 7 is connected to the signal input end of the piezoelectric ceramic tube 6, the signal input end of the second voltage signal source 7 is connected to the first signal output end of the signal processing and control system 9, the first light output end of the fiber coupler 4 is connected to the light input end of the detector 8, the signal output end of the detector 8 is connected to the second signal input end of the signal processing and control system 9, and the second signal output end of the signal processing and control system 9 outputs the gyroscope output signal;

[0021] The fiber coupler 4 and fiber ring 5 form a fiber resonant cavity; the laser 2 outputs a continuous, constant-intensity, frequency-tunable narrow-linewidth laser, the laser linewidth being smaller than the linewidth of the transmission valley of the fiber resonant cavity. The laser frequency is determined by the voltage at the modulation signal input end of the laser 2. The greater the voltage, the greater the laser frequency, and the smaller the voltage, the smaller the laser frequency. The relationship between the voltage at the modulation signal input end of the laser 2 and the laser frequency output by the laser 2 is known.

[0022] The first signal output terminal and the second signal output terminal of the first voltage signal source 1 output the same periodic triangular wave voltage signal. The waveform of this periodic triangular wave voltage signal is as shown in FIG. Figure 2 As shown, the maximum voltage is U2 and the minimum voltage is U1. This periodic triangular wave voltage signal is loaded into the modulation signal input terminal of laser 2, so that the frequency tuning range of the laser output by laser 2 is equal to the free spectrum width when the fiber resonant cavity is stationary.

[0023] The outer diameter of the piezoelectric ceramic tube 6 is determined by the voltage at the signal input end of the piezoelectric ceramic tube 6. The smaller the voltage, the larger the outer diameter of the piezoelectric ceramic tube 6, and the larger the voltage, the smaller the outer diameter of the piezoelectric ceramic tube 6. The relationship between the voltage at the signal input end of the piezoelectric ceramic tube 6 and the outer diameter of the piezoelectric ceramic tube 6 is known.

[0024] The signal output end of the second voltage signal source 7 outputs a DC voltage signal, and the DC voltage signal is applied to the signal input end of the piezoelectric ceramic tube 6 to control the outer diameter of the piezoelectric ceramic tube 6;

[0025] The optical fiber ring 5 is wound around and fixed on the outer surface of the piezoelectric ceramic tube 6. Figure 3 As shown;

[0026] The optical fiber coupler 4 is a 2×2 optical fiber coupler;

[0027] The signal processing and control system 9 is composed of a sampling filter circuit 9-1 and a comparison output circuit 9-2;

[0028] The first signal input end of the sampling and filtering circuit 9-1 is the first signal input end of the signal processing and control system 9, the second signal input end of the sampling and filtering circuit 9-1 is the second signal input end of the signal processing and control system 9, the first signal output end of the comparison output circuit 9-2 is the first signal output end of the signal processing and control system 9, and the second signal output end of the comparison output circuit 9-2 is the second signal output end of the signal processing and control system 9; the second signal output end of the first voltage signal source 1 is connected to the first signal input end of the sampling and filtering circuit 9-1, the signal output end of the detector 8 is connected to the second signal input end of the sampling and filtering circuit 9-1, the first signal output end of the sampling and filtering circuit 9-1 is connected to the first signal input end of the comparison output circuit 9-2, the second signal output end of the sampling and filtering circuit 9-1 is connected to the second signal input end of the comparison output circuit 9-2, the first signal output end of the comparison output circuit 9-2 is connected to the signal input end of the second voltage signal source 7, and the second signal output end of the comparison output circuit 9-2 outputs the gyroscope output signal.

[0029] Working principle: The fiber coupler 4 and fiber ring 5 constitute a fiber resonant cavity; the first voltage signal source 1 outputs a periodic triangular wave voltage signal which is loaded into the modulation signal input terminal of the laser 2 to tune the frequency of the laser output by the laser 2. At the same time, this periodic triangular wave voltage signal is sent to the signal processing and control system 9. The laser 2 outputs a continuous and constant intensity laser which enters the polarization controller 3. The polarization controller 3 selects to retain one polarization state of the laser. The laser output by the polarization controller 3 enters the fiber resonant cavity. Since the laser line width is smaller than the line width of the transmission valley of the fiber resonant cavity, a fiber resonant cavity can be obtained. The transmission spectrum of the optical fiber resonant cavity is detected by the detector 8. The transmission spectrum signal output by the detector 8 enters the signal processing and control system 9. The signal processing and control system 9 collects the periodic triangular wave voltage signal output by the first voltage signal source 1 and collects the transmission spectrum signal. At the same time, the signal processing and control system 9 outputs a control signal to the second voltage signal source 7 to control the voltage value of the DC voltage signal output by the second voltage signal source 7, thereby controlling the outer diameter of the piezoelectric ceramic tube 6. Finally, the signal processing and control system 9 outputs a gyro output signal, which includes the size and direction of the rotation speed.

[0030] When light enters a fiber resonant cavity, the product of the cavity length of the fiber resonant cavity and the fiber refractive index is an integer multiple of some light wavelengths. These light wavelengths are called the "resonance wavelengths" of the fiber resonant cavity, and the light frequency corresponding to the resonant wavelength of the fiber resonant cavity is called the "resonance frequency" of the fiber resonant cavity. The frequency interval between any two adjacent resonant frequencies of the fiber resonant cavity is equal, and this frequency interval is called the "free spectral width" of the fiber resonant cavity. Light with a frequency equal to the resonant frequency of the fiber resonant cavity can resonate in the fiber resonant cavity, and the transmittance of light is minimum during resonance. Therefore, the transmission spectrum of the fiber resonant cavity is a transmission valley with equal frequency intervals. This frequency interval is the free spectral width of the fiber resonant cavity, and the minimum transmittance of the transmission valley is the transmittance at the resonant frequency of the fiber resonant cavity.

[0031] Before using the fiber optic gyroscope, it is necessary to "zero" under static conditions. The process of "zeroing" is as follows: first, the signal processing and control system 9 outputs a control signal and sends it to the second voltage signal source 7, so that the voltage value output by the second voltage signal source 7 is 0; then, the first voltage signal source 1 outputs a triangular wave voltage signal with a period of T and sends it to the signal processing and control system 9, and loads this triangular wave voltage signal to the modulation signal input end of the laser 2 to tune the frequency of the laser output by the laser 2. Since the maximum voltage value of the triangular wave voltage signal is set to U2 and the minimum voltage value is U1 (the size of U2 and U1 depends on the voltage-frequency tuning parameters of the laser 2 and the free spectrum width of the optical fiber resonant cavity when it is static), the laser can be tuned. The frequency tuning range of the output laser light is equal to the free spectrum width of the optical fiber resonator when it is stationary. Thus, the period of the transmission spectrum of the laser light through the optical fiber resonator is also T, and each period of the transmission spectrum contains only one transmission valley. The transmission spectrum of the optical fiber resonator is detected by a detector 8, and the transmission spectrum signal output by the detector 8 enters a signal processing and control system 9. Then, the signal processing and control system 9 obtains the triangular wave voltage signal and the transmission spectrum signal, compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the minimum voltage value U1 of the triangular wave voltage signal as the time origin, and reads the time t0 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal.

[0032] The working process of the fiber optic gyroscope is as follows: first, the signal processing and control system 9 outputs a control signal and sends it to the second voltage signal source 7, so that the voltage value output by the second voltage signal source 7 is 0; then, the first voltage signal source 1 outputs a triangular wave voltage signal with a period of T and sends it to the signal processing and control system 9, and loads this triangular wave voltage signal to the modulation signal input end of the laser 2 to tune the frequency of the laser output by the laser 2. At the same time, the transmission spectrum of the optical fiber resonant cavity with a period of T is detected by the detector 8, and the transmission spectrum signal output by the detector 8 enters the signal processing and control system 9; then, the signal processing and control system 9 obtains the triangular wave voltage signal and the transmission spectrum signal. If there is no transmission valley in the transmission spectrum signal, the signal processing and control system 9 outputs a control signal and sends it to the second voltage signal source 7, so that the voltage value of the DC voltage signal output by the second voltage signal source 7 gradually increases, thereby gradually reducing the outer diameter of the piezoelectric ceramic tube 6 and the radius of the optical fiber ring 5. The rotation speed is small until a transmission valley appears in the transmission spectrum signal. Then, the signal processing and control system 9 compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the minimum voltage U1 of the triangular wave voltage signal as the time origin, and reads the time t1 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal. If t1 is greater than t0, the rotation speed direction is clockwise. If t1 is less than t0, the rotation speed direction is counterclockwise. Since the corresponding relationship between the voltage at the modulation signal input end of the laser 2 and the laser frequency output by the laser 2 is known, and the corresponding relationship between the voltage at the signal input end of the piezoelectric ceramic tube 6 and the outer diameter of the piezoelectric ceramic tube 6 is known, the rotation speed is obtained from the absolute value of the difference between t1 and t0. Finally, the signal processing and control system 9 outputs a gyro output signal, which includes the rotation speed magnitude and direction.

[0033] Working principle of signal processing and control system 9:

[0034] Before use, the fiber optic gyroscope needs to be "zeroed" under static conditions. The process of "zeroing" of the signal processing and control system 9 is as follows: first, the comparison output circuit 9-2 outputs a control signal 1 and sends it to the second voltage signal source 7, so that the voltage value output by the second voltage signal source 7 is 0; then, the sampling and filtering circuit 9-1 samples the triangular wave voltage signal with a period of T output by the first voltage signal source 1, and sends the triangular wave voltage signal to the comparison output circuit 9-2. At the same time, the sampling and filtering circuit 9-1 samples the transmission spectrum signal with a period of T output by the detector 8, filters the transmission spectrum signal, and sends it to the comparison output circuit 9-2; after the comparison output circuit 9-2 obtains the triangular wave voltage signal and the transmission spectrum signal, it compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the minimum voltage value U1 of the triangular wave voltage signal as the time origin, and reads the time t0 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal;

[0035] When the fiber optic gyroscope is working, the working process of the signal processing and control system 9 is as follows: first, the comparison output circuit 9-2 outputs a control signal 1 and sends it to the second voltage signal source 7, so that the voltage value output by the second voltage signal source 7 is 0; then, the sampling and filtering circuit 9-1 samples the triangular wave voltage signal with a period of T output by the first voltage signal source 1, and sends the triangular wave voltage signal to the comparison output circuit 9-2. At the same time, the sampling and filtering circuit 9-1 samples the transmission spectrum signal with a period of T output by the detector 8, filters the transmission spectrum signal and sends it to the comparison output circuit 9-2; after the comparison output circuit 9-2 obtains the triangular wave voltage signal and the transmission spectrum signal, if there is no transmission valley in the transmission spectrum signal, the comparison output circuit 9-2 outputs a control signal 2 and sends it to the second voltage signal source 7, so that the voltage value of the DC voltage signal output by the second voltage signal source 7 gradually increases, thereby gradually reducing the outer diameter of the piezoelectric ceramic tube 6 and gradually increasing the radius of the optical fiber ring 5. Gradually decreases until a transmission valley appears in the transmission spectrum signal; then, the comparison output circuit 9-2 compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the moment corresponding to the minimum voltage value U1 of the triangular wave voltage signal as the time origin, and reads the moment t1 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal. If t1 is greater than t0, the rotation speed direction is clockwise; if t1 is less than t0, the rotation speed direction is counterclockwise. Since the relationship between the voltage at the modulation signal input end of the laser 2 and the laser frequency output by the laser 2 is known, and the relationship between the voltage at the signal input end of the piezoelectric ceramic tube 6 and the outer diameter of the piezoelectric ceramic tube 6 is known, the rotation speed is obtained from the absolute value of the difference between t1 and t0; finally, the comparison output circuit 9-2 outputs the gyroscope output signal, and the gyroscope output signal includes the rotation speed magnitude and direction.

Claims

1. A large dynamic range resonant fiber gyroscope comprising a first voltage signal source, a laser, a polarization controller, a fiber coupler, a fiber ring, a piezoelectric ceramic tube, a second voltage signal source, a detector, and a signal processing and control system; characterized in that: The first signal output end of the first voltage signal source is connected to the modulation signal input end of the laser, the second signal output end of the first voltage signal source is connected to the first signal input end of the signal processing and control system, the optical output end of the laser is connected to the optical input end of the polarization controller, the optical output end of the polarization controller is connected to the first optical input end of the optical fiber coupler, the optical fiber ring is respectively connected to the second optical input end and the second optical output end of the optical fiber coupler, the optical fiber ring is wound around and fixed on the outer surface of the piezoelectric ceramic tube, the optical fiber coupler is a 2×2 optical fiber coupler, the signal output end of the second voltage signal source is connected to the signal input end of the piezoelectric ceramic tube, the signal input end of the second voltage signal source is connected to the first signal output end of the signal processing and control system, the first optical output end of the optical fiber coupler is connected to the optical input end of the detector, the signal output end of the detector is connected to the second signal input end of the signal processing and control system, and the second signal output end of the signal processing and control system outputs the gyroscope output signal; the optical fiber coupler and the optical fiber ring constitute Fiber resonator; the laser outputs a continuous, constant-intensity, frequency-tunable narrow-linewidth laser, the linewidth of the laser being smaller than the linewidth of the transmission valley of the fiber resonator, and the frequency of the laser corresponding to the voltage at the modulation signal input end of the laser, wherein the greater the voltage, the greater the laser frequency, and the smaller the voltage, the smaller the laser frequency; the first signal output end and the second signal output end of the first voltage signal source output the same periodic triangular wave voltage signal, wherein the maximum voltage of this periodic triangular wave voltage signal is U2 and the minimum voltage is U1, and this periodic triangular wave voltage signal is loaded onto the modulation signal input end of the laser, so that the frequency tuning range of the laser output by the laser is equal to the free spectral width of the fiber resonator when it is stationary; the outer diameter of the piezoelectric ceramic tube changes corresponding to the voltage at its signal input end, wherein the smaller the voltage, the larger the outer diameter of the piezoelectric ceramic tube, and the larger the voltage, the smaller the outer diameter of the piezoelectric ceramic tube; the signal output end of the second voltage signal source outputs a DC voltage signal, and the DC voltage signal is loaded onto the signal input end of the piezoelectric ceramic tube to control the outer diameter of the piezoelectric ceramic tube; When the fiber optic gyroscope is working, the signal processing and control system outputs a control signal and sends it to the second voltage signal source, so that the voltage value output by the second voltage signal source is 0; then, the first voltage signal source outputs a triangular wave voltage signal with a period of T and sends it to the signal processing and control system, and the triangular wave voltage signal is loaded into the modulation signal input end of the laser. At the same time, the transmission spectrum of the optical fiber resonant cavity with a period of T is detected by the detector, and the transmission spectrum signal output by the detector enters the signal processing and control system; then, the signal processing and control system obtains the triangular wave voltage signal and the transmission spectrum signal. If there is no transmission valley in the transmission spectrum signal, the signal processing and control system outputs a control signal and sends it to the second voltage signal source, so that the voltage value of the DC voltage signal output by the second voltage signal source gradually increases, thereby gradually reducing the outer diameter of the piezoelectric ceramic tube and the radius of the optical fiber ring until a transmission valley appears in the transmission spectrum signal; then, the signal processing and control system compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the triangular wave voltage signal, and generates a signal signal. The signal processing and control system compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the minimum voltage U1 of the triangular wave voltage signal as the time origin, and reads the time corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal. If the time t1 is greater than the time t0, the rotation speed direction is clockwise, and if the time t1 is less than the time t0, the rotation speed direction is counterclockwise, and the rotation speed magnitude is obtained by the absolute value of the difference between the time t1 and the time t0. Wherein, the time t0 is the voltage minimum U1 of the triangular wave voltage signal with a period of T output by the first voltage signal source of the optical fiber gyroscope under static conditions. The signal processing and control system compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the voltage minimum U1 of the triangular wave voltage signal as the time origin, and reads the time corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal. Finally, the signal processing and control system outputs a gyro output signal, and the gyro output signal includes the magnitude and direction of the rotation speed.

2. The large dynamic range resonant fiber gyroscope according to claim 1, characterized in that: The signal processing and control system includes a sampling and filtering circuit and a comparison output circuit; the first signal input end of the sampling and filtering circuit is the first signal input end of the signal processing and control system, the second signal input end of the sampling and filtering circuit is the second signal input end of the signal processing and control system, the first signal output end of the comparison output circuit is the first signal output end of the signal processing and control system, and the second signal output end of the comparison output circuit is the second signal output end of the signal processing and control system; the second signal output end of the first voltage signal source is connected to the first signal input end of the sampling and filtering circuit, the signal output end of the detector is connected to the second signal input end of the sampling and filtering circuit, the first signal output end of the sampling and filtering circuit is connected to the first signal input end of the comparison output circuit, the second signal output end of the sampling and filtering circuit is connected to the second signal input end of the comparison output circuit, the first signal output end of the comparison output circuit is connected to the signal input end of the second voltage signal source, and the second signal output end of the comparison output circuit outputs a gyroscope output signal.

3. The large dynamic range resonant fiber gyroscope according to claim 2, characterized in that: When the fiber optic gyroscope is in operation, the comparison output circuit outputs a first control signal and sends it to the second voltage signal source, so that the voltage value output by the second voltage signal source is 0; then, the sampling and filtering circuit samples the triangular wave voltage signal with a period of T output by the first voltage signal source and sends the triangular wave voltage signal to the comparison output circuit. At the same time, the sampling and filtering circuit samples the transmission spectrum signal with a period of T output by the detector, filters the transmission spectrum signal, and then sends it to the comparison output circuit; after the comparison output circuit obtains the triangular wave voltage signal and the transmission spectrum signal, if there is no transmission valley in the transmission spectrum signal, the comparison output circuit outputs a second control signal and sends it to the second voltage signal source, so that the voltage value of the DC voltage signal output by the second voltage signal source gradually increases, thereby gradually reducing the outer diameter of the piezoelectric ceramic tube and the radius of the optical fiber ring, until a transmission valley appears in the transmission spectrum signal; Then, the comparison output circuit compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same cycle of the triangular wave voltage signal and the transmission spectrum signal, takes the time corresponding to the minimum voltage value U1 of the triangular wave voltage signal as the time origin, reads the time t1 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal, if the time t1 is greater than the time t0, the rotation speed direction is clockwise, if the time t1 is less than the time t0, the rotation speed direction is counterclockwise, and the rotation speed magnitude is obtained from the absolute value of the difference between the time t1 and the time t0; finally, the comparison output circuit outputs the gyroscope output signal, and the gyroscope output signal includes the rotation speed magnitude and direction.

4. The large dynamic range resonant fiber gyroscope according to claim 2 or 3, characterized in that: Before use, the fiber optic gyroscope needs to be "zeroed" under static conditions. The "zeroing" method is as follows: the comparison output circuit outputs a first control signal and sends it to the second voltage signal source, so that the voltage value output by the second voltage signal source is 0; then, the sampling and filtering circuit samples the triangular wave voltage signal with a period of T output by the first voltage signal source and sends the triangular wave voltage signal to the comparison output circuit. At the same time, the sampling and filtering circuit samples the transmission spectrum signal with a period of T output by the detector, filters the transmission spectrum signal, and sends it to the comparison output circuit; after the comparison output circuit obtains the triangular wave voltage signal and the transmission spectrum signal, it compares the triangular wave voltage signal and the transmission spectrum signal on the same time axis, intercepts the same period of the triangular wave voltage signal and the transmission spectrum signal, and uses the time corresponding to the minimum voltage value U1 of the triangular wave voltage signal as the time origin to read the time t0 corresponding to the minimum transmittance of the transmission valley in the transmission spectrum signal.

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