A method and system for predicting the residual life of a laser gyroscope

Abstract

This invention discloses a method and system for predicting the remaining lifetime of a laser gyroscope, belonging to the field of laser gyroscope testing technology. The method calculates the first degradation rate of the resonant cavity and the second degradation rate of the cathode by collecting discharge data from the laser gyroscope. Then, it updates the first and second degradation rates based on the lock-in width and beat frequency signal-to-noise ratio. Simultaneously, it collects thin-film images of the getter to calculate the third degradation rate of the getter. A relationship matrix is ​​generated based on the first, second, and third degradation rates. A degradation model is fitted based on the relationship matrix, and the remaining lifetime of the laser gyroscope is predicted based on the degradation model. This invention can effectively screen out laser gyroscope products with substandard remaining lifetime, thereby improving the reliability of laser gyroscopes in applications such as aviation and aerospace.

Description

Technical Field

[0001] This invention relates to the field of laser gyroscope detection technology, and in particular to a method and system for predicting the remaining lifetime of a laser gyroscope. Background Technology

[0002] As a core sensor for high-precision attitude measurement of carriers in aviation and aerospace fields, the performance and reliability of laser gyroscopes directly affect the navigation accuracy and mission safety of aircraft. To meet the stringent requirements of long-term missions, the service life of laser gyroscopes must be continuously evaluated. In existing technologies, the service life and reliability of laser gyroscopes are generally assessed by conducting accelerated life tests under environmental stress before they are put into use. Chinese Patent Publication No. CN110567487B discloses a laser gyroscope reliability testing system and method. This method applies electrical and thermal stresses to multiple groups of laser gyroscopes to conduct accelerated life tests. Based on multiple sets of degradation data, a linear degradation model of the laser gyroscope is determined. Combined with relevant parameters, a pseudo-life value for the test sample is derived. Then, based on the evaluation model of the laser gyroscope's reliability parameter MTBF, the reliability of the laser gyroscope under corresponding conditions is obtained, realizing reliability assessment during the laser gyroscope product development process. However, in actual work, due to significant differences in the operating environments of different laser gyroscopes, the conditions set in the pre-conducted accelerated life tests cannot fully cover all real-world operating conditions, resulting in life prediction results that cannot accurately reflect individual product differences and performance degradation during actual operation. There is a need for further improvement of existing technology. Summary of the Invention

[0003] To address the shortcomings of the existing technology, this invention proposes a method and system for predicting the remaining lifetime of a laser gyroscope. This method predicts the remaining lifetime of the laser gyroscope by collecting the degradation rates of three core components: the resonant cavity, the cathode, and the getter, thereby improving the reliability of laser gyroscopes in aviation, aerospace, and other fields.

[0004] The technical solution of this invention is implemented as follows:

[0005] A method for predicting the remaining lifetime of a laser gyroscope includes the following steps:

[0006] Step 1: Preset the first angular velocity for measuring the width of the laser gyroscope lock zone and the second angular velocity for measuring the beat frequency signal-to-noise ratio, and collect the initial margin of the getter;

[0007] Step 2: Enter the working state, collect pump current and output power, calculate the first degradation rate of the resonant cavity, collect the start-up voltage and discharge voltage, calculate the second degradation rate of the cathode, collect the getter temperature and calculate the activation rate of the getter.

[0008] Step 3: Enter the first detection state, apply the first angular velocity to the laser gyroscope, collect the response angular velocity, calculate the lock zone width, then apply the second angular velocity to the laser gyroscope, collect the signal power and noise power, and calculate the beat frequency signal-to-noise ratio;

[0009] Step 4: Enter the second detection state, acquire instantaneous images of the getter, calculate the current area and average thickness of the getter film, and calculate the third degradation rate of the getter by combining the initial margin and activation rate.

[0010] Step 5: Update the first degradation rate of the resonant cavity based on the locked region width, calculate the correlation coefficient based on the beat frequency signal-to-noise ratio and the locked region width, and update the second degradation rate of the cathode based on the correlation coefficient;

[0011] Step 6: Generate a relation matrix based on multiple sets of first degradation rate, second degradation rate, and third degradation rate. Fit a degradation model of the laser gyroscope based on the relation matrix. Predict the remaining lifetime of the laser gyroscope based on the degradation model. Return to Step 2.

[0012] In this invention, in step 2, a PI curve is plotted based on multiple sets of pump current and output power data to generate a threshold current and electro-optic conversion slope efficiency. The first degradation rate of the resonant cavity is calculated based on the electro-optic conversion slope efficiency, and the second degradation rate of the cathode is calculated based on the start-up voltage.

[0013] In this invention, in step 2, the total cavity loss of the resonant cavity is calculated based on the discharge voltage, threshold current and electro-optic conversion skew efficiency, and the activation rate of the getter is calculated based on the getter cavity temperature.

[0014] In this invention, in step 4, the current thin film region is extracted from the instantaneous image, the coordinates and gray values ​​of each pixel in the thin film region are collected, the area and average thickness of the current getter film are calculated, the current reserve of the getter is calculated based on the initial reserve and activation rate, and the third degradation rate of the getter is calculated by combining the area and average thickness.

[0015] In this invention, in step 5, the scattering loss of the resonant cavity is calculated based on the lock region width, the first degradation rate is updated in combination with the total cavity loss, the correlation coefficient is calculated based on the scattering loss and the beat frequency signal-to-noise ratio, and the second degradation rate of the cathode is updated based on the correlation coefficient.

[0016] In this invention, in step 6, the first degradation rate of N detections is combined to generate a first degradation sequence, the second degradation rate of N detections is combined to generate a second degradation sequence, the third degradation rate of N detections is combined to generate a third degradation sequence, and a relation matrix is ​​generated based on the first degradation sequence, the second degradation sequence, and the third degradation sequence.

[0017] In this invention, in step 6, the degradation rate of the resonant cavity, cathode, and getter is calculated based on the degradation model of the laser gyroscope fitted by the relation matrix. The failure time of the laser gyroscope is predicted by combining the failure threshold, the lifetime prediction sequence is updated, and the remaining lifetime of the laser gyroscope is calculated based on the updated lifetime prediction sequence.

[0018] A detection system for implementing the remaining lifetime prediction method of the laser gyroscope, comprising:

[0019] The device acquisition unit is configured to acquire the static parameters of the laser gyroscope;

[0020] The operating condition acquisition unit is configured to acquire dynamic parameters of the laser gyroscope when it enters the working state;

[0021] The first detection unit is configured to collect dynamic parameters of the laser gyroscope entering the first detection state;

[0022] The second detection unit is configured to collect dynamic parameters of the laser gyroscope entering the second detection state;

[0023] The data processing unit is configured to calculate the first degradation rate, the second degradation rate, the third degradation rate, and the activation rate of the inhaler;

[0024] The data analysis unit is configured to generate a relation matrix and fit a degradation model of the laser gyroscope;

[0025] The data prediction unit is configured to predict the remaining lifetime of the laser gyroscope;

[0026] The data storage unit is configured to store and update the first degradation sequence, the second degradation sequence, the third degradation sequence, and the lifetime prediction sequence.

[0027] In this invention, the static parameters include the initial margin of the getter, the dynamic parameters for entering the working state include: pump current, output power, discharge voltage, start-up voltage, and getter chamber temperature, the dynamic parameters for entering the first detection state include: lock zone width and beat frequency signal-to-noise ratio, and the dynamic parameters for entering the second detection state include: instantaneous image of the getter.

[0028] The present invention provides a method and system for predicting the remaining lifetime of a laser gyroscope, which has the following beneficial effects: The present invention collects discharge data from the laser gyroscope, calculates the first degradation rate of the resonant cavity and the second degradation rate of the cathode, and combines this with a third degradation rate obtained from getter film image analysis. This comprehensive consideration of multiple key factors affecting the lifetime of the laser gyroscope significantly improves the accuracy of the remaining lifetime prediction. Since the first and second degradation rates are collected during operation and are easily affected by other factors, and the first degradation rate of the resonant cavity is strongly correlated with the locking region width, while the second degradation rate of the cathode is strongly correlated with the locking region width and the beat frequency signal-to-noise ratio, the present invention updates the first and second degradation rates using the locking region width and beat frequency signal-to-noise ratio obtained from the first detection state, thereby improving the accuracy of equipment degradation prediction.

[0029] Furthermore, based on the above three degradation rates, three sets of degradation sequences are generated, a relation matrix is ​​generated based on the degradation sequences, and a degradation model is fitted accordingly to achieve scientific prediction of the remaining lifespan of the laser gyroscope, thereby improving the reliability of laser gyroscopes in aviation, aerospace and other fields. Attached Figure Description

[0030] Figure 1 This is a structural diagram of the laser gyroscope of the present invention;

[0031] Figure 2 This is a schematic diagram of the laser gyroscope of the present invention;

[0032] Figure 3 This is a flowchart of the method for predicting the remaining lifetime of a laser gyroscope according to the present invention;

[0033] Figure 4 This is a schematic diagram of the getter evaporation in the laser gyroscope of the present invention;

[0034] Figure 5 This is a schematic diagram of a thin film region image according to the present invention;

[0035] Figure 6 The PI curve of the preferred laser gyroscope of the present invention;

[0036] Figure 7 This is a preferred response angular velocity curve of the present invention;

[0037] Figure 8 This is a preferred beat frequency power spectrum curve of the present invention;

[0038] Figure 9 This is a lifetime curve diagram of a preferred laser gyroscope according to the present invention;

[0039] Figure 10 This is a block diagram of the detection system for implementing the remaining lifetime prediction method of the laser gyroscope according to the present invention;

[0040] Figure 11 This is a block diagram of the working condition acquisition unit of the present invention;

[0041] Figure 12 This is a block diagram of the first detection unit of the present invention;

[0042] Figure 13 This is a block diagram of the second detection unit of the present invention.

[0043] Reference numerals in the attached figures: getter assembly 10, glass plate 11, getter film 12, laser gyroscope 20, cathode emitter 21, resonant cavity 22, anode emitter 23, first plane mirror 24, second plane mirror 25, spherical mirror 26, light combining prism 27, getter cavity 28. Detailed Implementation

[0044] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0045] like Figure 1 and Figure 2 As shown, the laser gyroscope 20 includes a cathode emitter 21, a resonant cavity 22, an anode emitter 23, a first plane mirror 24, a second plane mirror 25, a spherical mirror 26, a beam combining prism 27, and a light signal detector. The cathode emitter 21 and the two sets of anode emitters 23 generate a first laser and a second laser, respectively. The first and second lasers are emitted in opposite directions and intersect at the beam combining prism 27 after passing through the first plane mirror 24, the second plane mirror 25, and the spherical mirror 26. The light signal detector receives the imaging signals of the first and second lasers and measures the angular velocity of the laser gyroscope based on the interference data of the imaging signals. To absorb the stray gas generated inside the laser gyroscope, a cylindrical gas-absorbing cavity 28 is machined on the laser gyroscope 20. A getter assembly 10 is placed in the gas-absorbing cavity 28. The getter assembly 10 consists of a tray, getter, spring, etc. The three components are placed into the gas-absorbing cavity 28 in sequence, and then covered with a glass pressure plate 11. The getter assembly is sealed and installed in the laser gyroscope 20 between the glass pressure plate 11 and the laser gyroscope body by means of optical adhesive.

[0046] During the long-term operation of a laser gyroscope, on the one hand, the getter capacity gradually approaches saturation due to the continuous adsorption of impurity gases, leading to an increase in the partial pressure of residual gas within the cavity and directly exacerbating the absorption loss of the resonant cavity. On the other hand, the cathode is sputtered under ion bombardment, and the resulting metal particles not only contaminate optical components such as mirrors, increasing optical scattering and absorption losses, but also cause continuous consumption of the cathode active material, resulting in a continuous decline in its electron emission capability and accelerating cathode aging. These processes together disrupt the discharge characteristics and significantly increase the total loss of the resonant cavity, forming a vicious cycle of performance degradation and ultimately leading to the failure of the laser gyroscope. This invention calculates the first degradation rate of the resonant cavity and the second degradation rate of the cathode by collecting discharge data from the laser gyroscope. The first and second degradation rates are then updated based on the lock-in width and beat frequency signal-to-noise ratio. Simultaneously, a thin-film image of the getter is collected to calculate the third degradation rate of the getter. A relationship matrix is ​​generated based on the first, second, and third degradation rates. A degradation model is fitted based on the relationship matrix, and the remaining lifetime of the laser gyroscope is predicted based on the degradation model. This allows for the screening of products with insufficient remaining lifetime, thereby improving the reliability of laser gyroscopes in applications such as aviation and aerospace. Example 1

[0047] like Figures 1 to 9 As shown, the present invention provides a method for predicting the remaining lifetime of a laser gyroscope, comprising the following steps.

[0048] Step 1: Preset a first angular velocity for measuring the width of the lock zone of the laser gyroscope and a second angular velocity for measuring the beat frequency signal-to-noise ratio, and collect the initial getter margin. Specifically, after the solid getter is evaporated into the getter chamber of the laser gyroscope to form an initial getter film, the mass of the remaining solid getter is collected, which is the initial getter margin. The first angular velocity is set according to the accuracy of the laser gyroscope, usually between 0.001° / h and 0.1° / h, and the second angular velocity needs to be greater than the lock zone, usually between 1° / s and 10° / s. For example, in this embodiment, the first angular velocity is set to 0.01° / h and the second angular velocity is set to 2° / s.

[0049] Step 2: Enter the working state, collect pump current and output power, calculate the first degradation rate of the resonant cavity, collect the start-up voltage and discharge voltage, calculate the second degradation rate of the cathode, collect the getter temperature and calculate the getter activation rate. The degradation rate of this invention is used to characterize the degradation of components. The prediction methods for the first and second degradation rates are described below.

[0050] Calculate the first degradation rate of the resonant cavity. For example... Figure 6 Based on multiple sets of pump current I and output power P data, a PI curve was plotted and linearly fitted to obtain the curve expression P=η·(II) th ), where the intercept of the curve on the I-axis is I. thLet η be the threshold current, and η be the slope of the curve, representing the electro-optic conversion efficiency. As the laser gyroscope gradually degrades, the electro-optic conversion efficiency will gradually decrease. The first degradation rate R1 of the resonant cavity is calculated based on the electro-optic conversion efficiency η, where R1 = (η0 - η) / η0. η0 is the initial value of the electro-optic conversion efficiency, obtained through experimental calibration, typically between 0.01% and 0.1%. For example, in this embodiment, η0 = 0.02%.

[0051] The second degradation rate of the cathode is calculated. Cathode degradation can lead to difficulties in starting the laser gyroscope, specifically manifested as an increase in the start-up voltage or threshold current. Based on the start-up voltage U1, the second degradation rate R2 of the cathode is calculated. In this embodiment, the relationship between device parameter changes and the second degradation rate is expressed as a linear function, i.e., R2 = (U1 - U0) / U0. U0 is the initial start-up voltage, obtained through experimental calibration, typically 1500V. In other preferred embodiments, the relationship between parameter changes and degradation rate can be generated through lifetime testing, such as accelerated lifetime curves or decelerated lifetime curves.

[0052] In addition, based on the discharge voltage U2 and the threshold current I th The total cavity loss δ of the resonant cavity is calculated using the electro-optic conversion slope efficiency η. Among them, δ OC The output coupling loss is typically equal to the transmittance of the output coupling mirror. pump This represents the pump power of the upper energy level of the laser in the laser gyroscope. e is the elementary charge, approximately 1.6 × 10⁻⁶. -19 C. E is the photon energy, E = hc / λ. h is Planck's constant, which is approximately 6.63 × 10⁻⁶. -34 c is the speed of light, which is approximately 3 × 10⁻⁶. 8 m / s. λ is the wavelength of the laser gyroscope, typically 632.8 nm.

[0053] Calculate the activation rate of the getter. The activation rate refers to the mass of barium diffused per second from a unit area of ​​getter, expressed in kg / (m²). 2 The activation rate (J) is the rate at which barium atoms diffuse to the getter surface when the remaining solid getter is activated by heat. The activation rate is calculated as J = D0·exp(-E). a / K B T)·(-dC / dx). Where D0 is the diffusion coefficient, which is related to the getter material and is expressed in m³. 2 / s. E a The activation energy for barium atom diffusion is typically between 1.5 and 2.0 eV. K B Here is the Boltzmann constant, which is approximately 8.617 × 10⁻⁶. -5 eV / K. C is the mass concentration of barium atoms in the getter, in kg / m³. 3dC / dx represents the concentration gradient of barium atoms along the thickness direction (x-direction) of the getter. The negative sign indicates that the diffusion direction is from the high concentration region (inside the getter) to the low concentration region (on the getter surface). T is the getter chamber temperature in Kelvin. In this embodiment, a thermistor is placed on the surface of the getter chamber, and the instantaneous resistance value of the thermistor is collected. The instantaneous temperature of the getter chamber can be calculated based on the instantaneous resistance value, and the average of multiple instantaneous temperatures is used as the getter chamber temperature.

[0054] Step 3: Enter the first detection state, apply a first angular velocity to the laser gyroscope, collect the response angular velocity, calculate the lock zone width, then apply a second angular velocity to the laser gyroscope, collect the signal power and noise power, and calculate the beat frequency signal-to-noise ratio. In this embodiment, in the first detection state, the laser gyroscope is mounted on a single-axis rate turntable, and a specified angular velocity is applied to the laser gyroscope by controlling the rotation of the turntable.

[0055] Specifically, first, an initial angular velocity is applied to the laser gyroscope to initiate rotation in one direction (e.g., clockwise). During rotation, the gyroscope's response angular velocity (output angular velocity) is continuously collected. The critical point where the gyroscope's response angular velocity jumps from zero to a non-zero value is found. Based on the turntable's rotational angular velocity and time, the input angular velocity value Ω1 corresponding to this critical point is calculated. Then, the turntable's rotation direction is changed (counterclockwise) to obtain the input angular velocity value Ω2 at another critical point. Figure 7 As shown, the lock area width Ω L =|Ω 1- Ω2|. Next, a second angular velocity is applied to the laser gyroscope, and the beat frequency power of the laser gyroscope is collected using a spectrum analyzer, such as... Figure 8 As shown, the signal power P of the laser gyroscope is extracted from the spectrum. s and noise power P n Calculate the beat frequency signal-to-noise ratio (SNR) as follows: SNR = 10 × lg(P s / P n ).

[0056] Step 4: Enter the second detection state, acquire instantaneous images of the getter, calculate the current area and average thickness of the getter film, and calculate the third degradation rate of the getter based on the initial margin and activation rate. A preferred method for acquiring instantaneous images of the getter involves installing a CCD image acquisition device above the getter area of ​​the laser gyroscope, with the CCD lens facing the getter cavity 28 of the laser gyroscope 20 to ensure complete acquisition of the getter cavity image. During the process of the getter film absorbing impurity gases, after the original film absorbs the impurity gases and is consumed, its color changes from dark gray to light white. For example... Figure 5 As shown, the getter film 12 changes due to the absorption of impurities, and its shape gradually shrinks and becomes smaller.

[0057] A circular region image of the getter cavity is segmented from a transient image using an ideal mask for the getter film. This circular region image is then processed in grayscale. Based on a grayscale threshold, the current film region is extracted. The coordinates and grayscale values ​​of each pixel in this film region are collected to generate the shape and pixel features of the current getter film. The area and average thickness of the current getter film are calculated based on these shape and pixel features. The current reserve of the getter is calculated based on the initial reserve and activation rate. The third degradation rate of the getter is then calculated by combining the area and average thickness of the current getter film. Example 2 further discloses a preferred method for calculating the third degradation rate of the getter.

[0058] Step 5: Update the first degradation rate of the resonant cavity based on the locked region width, calculate the correlation coefficient based on the beat frequency signal-to-noise ratio and the locked region width, and update the second degradation rate of the cathode based on the correlation coefficient.

[0059] The first degradation rate of the resonant cavity is updated. Mirror contamination caused by cathode sputtering is the main cause of resonant cavity degradation, directly resulting in increased scattering loss and consequently, an increased lock-in width. Based on the lock-in width Ω... L Calculate the scattering loss δ of the resonant cavity s δ s =(Ω L πLS rc ) / (k s cλ). Where L is the perimeter of the resonant cavity, S rc Let be the area enclosed by the resonant cavity. Let c be the speed of light, approximately 3 × 10⁻⁶. 8 m / s. λ is the wavelength of the laser gyroscope, typically 632.8 nm. k s The proportionality constant is determined by the geometry and scattering characteristics of the resonant cavity and can be obtained through experimental calibration; it is typically around 10. -3 ~10 -2 Between. Based on scattering loss δ s The total cavity loss δ updates the first degradation rate of the resonant cavity, R1'=[δ s / (δ-δ0)]·R1, where δ0 is the initial value of the total cavity loss.

[0060] The second degradation rate of the updated cathode is determined. As the cathode gradually degrades, the measured beat frequency signal-to-noise ratio will gradually decrease. This is based on the scattering loss δ. s The correlation coefficient γ is calculated based on the beat frequency signal-to-noise ratio (SNR), where γ = [1-δ]. s / (δ-δ0)]·[(SNR0-SNR) / SNR0], where SNR0 is the initial signal-to-noise ratio. The second degradation rate of the cathode is updated based on the correlation coefficient γ, R2'=γ·R2.

[0061] Step 6: Generate a relationship matrix based on multiple sets of first, second, and third degradation rates. Fit a degradation model of the laser gyroscope based on the relationship matrix, predict the remaining lifetime of the laser gyroscope based on the degradation model, and return to Step 2. Specifically, combine the first degradation rate from N detections to generate a first degradation sequence, combine the second degradation rate from N detections to generate a second degradation sequence, and combine the third degradation rate from N detections to generate a third degradation sequence. Generate a relationship matrix based on the first, second, and third degradation sequences. For example, assuming N=10 and the detection interval Δt=5h, the laser gyroscope is detected every 5 hours. When the number of detections is greater than or equal to 10, the latest 10 sets of degradation rates are extracted as the data for the current lifetime prediction. When performing the next lifetime prediction, return to Step 2, generate a new set of degradation rates, and update the degradation sequence.

[0062] The first, second, and third degradation sequences record degradation data for the three core components: the resonant cavity, the cathode, and the getter, respectively. As a whole, the degradation data of different components of the laser gyroscope are interconnected. This invention describes the correlation of this degradation data using a relationship matrix, thereby fitting a degradation model for the core components of the laser gyroscope. Furthermore, the failure time of the laser gyroscope is predicted based on the degradation model, and the lifetime prediction sequence is updated. The remaining lifetime of the laser gyroscope is then predicted based on the updated lifetime prediction sequence. The lifetime prediction sequence is the set of predicted failure times of the laser gyroscope each time. Example 3 further discloses a preferred method for fitting the degradation model and predicting the remaining lifetime. Example 2

[0063] The data related to the first and second degradation rates are directly collected during the operation of the laser gyroscope, and data interference during operation is reduced by adjusting the lock zone width and beat frequency signal-to-noise ratio. The third degradation rate is predicted using an image algorithm. This embodiment further discloses a preferred method for calculating the third degradation rate of the getter.

[0064] First, a momentary image of the getter is acquired, and the shape and pixel features of the current getter film are extracted. Specifically, in this embodiment, a circular mask layer is set as an ideal mask for the getter film based on the glass pressure plate 11. The pixel values ​​of the ideal mask layer are the same as those of the circular mask layer. Based on this, the circular region image of the getter cavity is segmented from the momentary image. The circular region image is subjected to grayscale processing to generate a grayscale threshold, and pixels with grayscale values ​​less than or equal to the grayscale threshold are extracted. The grayscale values ​​of other pixels are set to 255 (white). The non-white area is the getter film area. The coordinates and grayscale values ​​of each pixel in this film area are acquired to generate the shape and pixel features of the current getter film.

[0065] Next, calculate the area and average thickness of the current getter film. Based on the shape characteristics of the current getter film, count the number of pixels N1, and calculate the area S' of the current getter film, S' = AN1 / N0, where A is the surface area of ​​the getter cavity base and N0 is the total number of pixels in the circular region. The pixel grayscale value p is obtained through experimental calibration. i With thickness d i relational function d i =f(p i Based on the pixel features of the current getter film, the thickness corresponding to each pixel is calculated, and the arithmetic mean of the thicknesses of all pixels is calculated as the average thickness d' of the current getter film.

[0066] Then, calculate the current remaining amount of the inhaled agent. Calculate the activation rate J based on the instantaneous temperature T of the inhalation chamber, J = D0·exp(-E a / K B T)·(-dC / dx). Where D0 is a proportionality constant, which is related to the getter material and is expressed in m³. 2 / s. E a The activation energy for barium atom diffusion is typically between 1.5 and 2.0 eV. K B Here is the Boltzmann constant, which is approximately 8.617 × 10⁻⁶. -5 eV / K. C is the mass concentration of barium atoms in the getter, in kg / m³. 3 dC / dx represents the concentration gradient of barium atoms along the thickness direction (x-direction) of the getter. The negative sign indicates that the diffusion direction is from the high concentration region (inside the getter) to the low concentration region (on the getter surface). The current remaining amount of getter, m2, is calculated based on the activation rate, where m2 = m1 - JS. x t. m1 is the initial balance of getter, S x t represents the surface area of ​​the getter, and t represents the operating time of the laser gyroscope.

[0067] Finally, the third degradation rate of the getter is calculated. Based on the current remaining amount of getter m2 and the current area S' and average thickness d' of the getter film, the third degradation rate R3 of the getter is calculated as follows: R3 = 1 - (ρS'd' + m2) / m x Where ρ is the density of the getter material, m x This refers to the mass of the getter before activation. Example 3

[0068] This embodiment further discloses the method for fitting the degradation model of the laser gyroscope in step 6 and predicting the remaining lifetime of the laser gyroscope.

[0069] The first degradation rate obtained from N detections is combined to generate the first degradation sequence G1 of the resonant cavity, G1=[R 11 ,R 12,…,R 1n ,…,R 1N The second degradation rate obtained from N detections is combined to generate the second degradation sequence G2 of the cathode, G2=[R]. 21 ,R 22 ,…,R 2n ,…,R 2N The third degradation rate obtained from N tests is combined to generate the third degradation sequence G3 of the getter, where G3 = [R]. 31 ,R 32 ,…,R 3n ,…,R 3N ].

[0070] Generate the relation matrix B of the laser gyroscope. b ij That is, the relationship coefficient between component i and component j, used to represent the influence of the degradation rate of component i on the degradation rate of component j, where i = 1, 2, 3 and j = 1, 2, 3. In this embodiment, components 1, 2, and 3 refer to the resonant cavity, cathode, and getter, respectively. For example, b 12 This indicates the effect of the resonant cavity degradation rate on the cathode degradation rate. The larger the value, the easier it is for the resonant cavity degradation to lead to accelerated cathode degradation.

[0071] When i=j, let b ij =0. When i≠j, the relation coefficient b is calculated based on the degenerate sequences G1, G2, and G3. ij , Among them, G i,avg G j,avg These are the degenerate sequences G. i G j The average value.

[0072] Fitting the degradation model V of the three core components in a laser gyroscope m For component m, its degradation model is: Among them, μ m The intrinsic rate constant for component m's degradation can be determined through accelerated lifetime experiments on laser gyroscopes. w This refers to the operating time of the laser gyroscope. (V) m That is, the degradation rate of component m. m = 1, 2, 3.

[0073] Failure time of laser gyroscopes is predicted based on a degradation model. First, the failure time of each component in the current number of tests is calculated. The failure time of component m is t. m =(R m0 -R mN ) / V m R m0Let m be the failure threshold of component m. The failure threshold of the resonant cavity is typically 20%~40%, the failure threshold of the cathode is typically 15%~30%, and the failure threshold of the getter is typically 75%~90%. Let the minimum failure time of the three core components be denoted as the failure time τ of the laser gyroscope. K , that is, τ K =min(t1,t2,t3).

[0074] Predict the remaining lifetime of the laser gyroscope. The failure time τ is based on the current number of detections Z. K The lifetime prediction sequence is updated, consisting of the predicted failure time of the laser gyroscope for each iteration. The updated lifetime prediction sequence is: {τ1, τ2, ..., τ} K}, where K is the total number of predictions, K = Z - N + 1, Z ≥ N. Remaining lifetime The remaining lifetime of this invention not only considers the failure time of different core components, but also the detection error of different number of tests, which can improve the accuracy of remaining lifetime prediction. For example... Figure 9 As the degradation rate of the core components of a laser gyroscope increases, its remaining lifespan continues to decrease. Example 4

[0075] like Figures 10 to 13 As shown, the detection system for implementing the remaining life prediction method of the laser gyroscope according to the present invention includes a device acquisition unit, a working condition acquisition unit, a first detection unit, a second detection unit, a data processing unit, a data analysis unit, a data prediction unit, and a data storage unit.

[0076] The device acquisition unit is configured to acquire static parameters of the laser gyroscope, including but not limited to the initial headroom of the getter. The acquisition unit is typically configured using I / O devices such as a computer.

[0077] The operating condition acquisition unit is configured to acquire dynamic parameters of the laser gyroscope entering the working state. These dynamic parameters include pump current, output power, discharge voltage, start-up voltage, and intake chamber temperature. Figure 11 The operating condition acquisition unit includes a temperature acquisition module, a power acquisition module, a voltage acquisition module, and a current acquisition module. The temperature acquisition module is used to acquire the instantaneous temperature of the intake chamber, the power acquisition module is used to acquire the output power, the voltage acquisition module is used to acquire the discharge voltage and the start-up voltage, and the current acquisition module is used to acquire the pump current.

[0078] The first detection unit is configured to collect dynamic parameters of the laser gyroscope entering the first detection state, including the locking zone width and the beat frequency signal-to-noise ratio. For example... Figure 12The first detection unit includes a rotation drive module, an angular velocity input module, an angular velocity acquisition module, a lock zone analysis module, a power acquisition module, and a noise analysis module. The rotation drive module controls the laser gyroscope's rotation based on the input angular velocity sent by the angular velocity input module. When the input angular velocity is the first angular velocity, the angular velocity acquisition module acquires the laser gyroscope's output angular velocity and sends it to the lock zone analysis module. The lock zone analysis module calculates the laser gyroscope's lock zone width based on the input and output angular velocities. When the input angular velocity is the second angular velocity, the power acquisition module acquires the laser gyroscope's beat frequency power and sends it to the noise analysis module. The noise analysis module extracts the signal power and noise power based on the beat frequency power, and then calculates the laser gyroscope's beat frequency signal-to-noise ratio.

[0079] The second detection unit is configured to acquire dynamic parameters of the laser gyroscope entering a second detection state, including instantaneous images of the getter. For example... Figure 13 The second detection unit includes a light generator, a beam splitter, a light receiver, and an image acquisition module. When the detection environment is set up according to this invention, the incident light from the light generator enters the getter chamber through the beam splitter, the reflected light enters the light receiver through the beam splitter, and the image acquisition module obtains a momentary image of the getter. Furthermore, a light shield can be arranged on the outside of the detection environment to reduce interference from ambient light sources.

[0080] The data processing unit is configured to calculate a first degradation rate, a second degradation rate, a third degradation rate, and the activation rate of the getter. Specifically, the data processing unit receives dynamic parameters from the operating condition acquisition unit, calculates the first degradation rate, the second degradation rate, the total cavity loss of the resonant cavity, and the activation rate of the getter; receives dynamic parameters from the first detection unit, updates the first and second degradation rates of the resonant cavity; and receives dynamic parameters from the second detection unit, calculates the third degradation rate of the getter.

[0081] The data analysis unit is configured to generate a relation matrix and fit a degradation model of the laser gyroscope. Based on the first, second, and third degradation sequences, the data analysis unit generates a relation matrix, fits degradation models of the three core components of the laser gyroscope according to the relation matrix, and calculates the degradation rates of the resonant cavity, cathode, and getter based on the degradation models.

[0082] The data prediction unit is configured to predict the remaining lifetime of the laser gyroscope. The data prediction unit predicts the failure time of the laser gyroscope based on the degradation rates of the resonant cavity, cathode, and getter, and combines this prediction with a lifetime prediction sequence to predict the remaining lifetime of the laser gyroscope.

[0083] The data storage unit is configured to store and update a first degradation sequence, a second degradation sequence, a third degradation sequence, and a lifetime prediction sequence. The data storage unit generates initial first, second, and third degradation sequences based on the first, second, and third degradation rates obtained from the previous N detections. Subsequently, the data processing unit sends the latest detected first, second, and third degradation rates to the data storage unit, which updates the corresponding degradation sequences. Furthermore, the data storage unit receives the currently detected and predicted failure time from the data prediction unit and adds it to the current lifetime prediction sequence, thereby updating the lifetime prediction sequence.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of predicting the residual life of a laser gyroscope, characterized in that, The method comprises the following steps: Step 1: preset a first angular velocity for measuring the lock-in width of the laser gyroscope and a second angular velocity for measuring the beat frequency signal-to-noise ratio, and collect the initial residual amount of the getter; Step 2: enter the working state, collect the pump current and output power, calculate the first degradation rate of the resonant cavity, collect the starting voltage and discharge voltage, calculate the second degradation rate of the cathode, collect the getter cavity temperature and calculate the activation rate of the getter; Step 3: enter the first detection state, apply the first angular velocity to the laser gyroscope, collect the response angular velocity, calculate the lock-in width, then apply the second angular velocity to the laser gyroscope, collect the signal power and noise power, and calculate the beat frequency signal-to-noise ratio; Step 4: enter the second detection state, collect the instantaneous image of the getter, calculate the area and average thickness of the current getter film, and calculate the third degradation rate of the getter in combination with the initial residual amount and the activation rate; Step 5: update the first degradation rate of the resonant cavity according to the lock-in width, calculate the correlation coefficient according to the beat frequency signal-to-noise ratio and the lock-in width, and update the second degradation rate of the cathode according to the correlation coefficient; Step 6: generate a relationship matrix based on multiple sets of first degradation rates, second degradation rates and third degradation rates, fit a degradation model of the laser gyroscope according to the relationship matrix, predict the remaining life of the laser gyroscope based on the degradation model, and return to Step 2.

2. The method of predicting the residual life of a laser gyro according to claim 1, wherein In Step 2, the P-I curve is drawn based on multiple sets of pump current and output power data to generate a threshold current and an electro-optical conversion slope efficiency, the first degradation rate of the resonant cavity is calculated based on the electro-optical conversion slope efficiency, and the second degradation rate of the cathode is calculated based on the starting voltage.

3. The method of predicting the residual life of a laser gyro according to claim 2, wherein In Step 2, the total cavity loss of the resonant cavity is calculated based on the discharge voltage, the threshold current and the electro-optical conversion slope efficiency, and the activation rate of the getter is calculated based on the getter cavity temperature.

4. The method of predicting the residual life of a laser gyro according to claim 1, wherein In Step 4, the current film area is extracted from the instantaneous image, the coordinates and gray values of each pixel point in the film area are collected, the area and average thickness of the current getter film are calculated, the current residual amount of the getter is calculated based on the initial residual amount and the activation rate, and the third degradation rate of the getter is calculated in combination with the area and the average thickness.

5. The method of predicting the residual life of a laser gyro according to claim 3, wherein In Step 5, the scattering loss of the resonant cavity is calculated based on the lock-in width, the first degradation rate is updated in combination with the total cavity loss, the correlation coefficient is calculated based on the scattering loss and the beat frequency signal-to-noise ratio, and the second degradation rate of the cathode is updated based on the correlation coefficient.

6. The method of predicting the residual life of a laser gyro as defined in claim 1, wherein In Step 6, the first degradation sequence is generated by combining the first degradation rates of N detections, the second degradation sequence is generated by combining the second degradation rates of N detections, the third degradation sequence is generated by combining the third degradation rates of N detections, and the relationship matrix is generated based on the first degradation sequence, the second degradation sequence and the third degradation sequence.

7. The method of predicting the residual life of a laser gyro according to claim 6, wherein In Step 6, the degradation model of the laser gyroscope is fitted according to the relationship matrix, the degradation rates of the resonant cavity, the cathode and the getter are calculated, the failure time of the laser gyroscope is predicted in combination with the failure threshold, the life prediction sequence is updated, and the remaining life of the laser gyroscope is calculated based on the updated life prediction sequence.

8. A detection system for implementing the method for predicting the residual life of a laser gyroscope according to claim 1, characterized in that, It comprises: A device acquisition unit configured to acquire static parameters of the laser gyroscope; A working condition acquisition unit configured to acquire dynamic parameters of the laser gyroscope in the working state; A first detection unit configured to acquire dynamic parameters of the laser gyroscope in the first detection state; a second detection unit configured to collect dynamic parameters of the laser gyroscope entering a second detection state; a data processing unit configured to calculate a first degradation rate, a second degradation rate, a third degradation rate, and an activation rate of the getter; a data analysis unit configured to generate a relationship matrix and fit a degradation model of the laser gyroscope; a data prediction unit configured to predict a remaining life of the laser gyroscope; a data storage unit configured to store and update a first degradation sequence, a second degradation sequence, a third degradation sequence, and a life prediction sequence.

9. The detection system of claim 8, wherein, The static parameters include an initial residual amount of the getter, the dynamic parameters entering the working state include a pump current, an output power, a discharge voltage, a starting voltage, and a getter cavity temperature, the dynamic parameters entering the first detection state include a lock width and a beat frequency signal-to-noise ratio, and the dynamic parameters entering the second detection state include a transient image of the getter.

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