Two-frequency mechanically dithered laser gyroscope geometric structure optimization design method based on response surface method

Abstract

The invention provides a two-frequency mechanically dithered laser gyroscope geometric structure optimization design method based on a response surface method. The two-frequency mechanically dithered laser gyroscope geometric structure optimization design method based on the response surface method comprises the following steps: S1, carrying out parametric modeling on a two-frequency mechanically dithered laser gyroscope, importing a three-dimensional model of the two-frequency mechanically dithered laser gyroscope into ANSYS Workbench software to carry out thermal-structural analysis, and determining the thermal deformation condition of an optical resonant cavity of the laser gyroscope; s2, constructing a response surface model by adopting a center composite design method, performing test design on the combination of the input parameters and the output parameters to obtain performance data of the laser gyroscope under different parameter combinations, and further fitting to obtain the response surface model of the maximum thermal deformation of the cavity. The two-frequency mechanically dithered laser gyroscope geometric structure optimization design method based on the response surface method has the advantages that the design period of the gyroscope can be optimized and shortened, and effective suppression of thermal deformation and optimization of the overall performance are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of dual-frequency mechanical dither laser gyroscopes, and in particular to a method for optimizing the geometric structure of a dual-frequency mechanical dither laser gyroscope based on a response surface methodology. Background Art

[0002] The laser gyroscope based on the Sagnac effect principle is a non-electromechanical medium and high precision inertial sensitive instrument that has been widely used in the field of inertial technology. It has the advantages of stable performance, high precision, long life, wide dynamic range, excellent linearity of proportional factor and stability. It is the core component of high-precision inertial navigation systems and is widely used in aerospace, ship navigation and precision guidance.

[0003] The quality of the laser gyro structural design directly affects its stability and reliability in complex environments. Temperature change is one of the main external disturbances faced by the laser gyro. During operation, due to the uneven distribution of internal heat sources and external ambient temperature fluctuations, the temperature field of the laser gyro will change significantly, thereby inducing thermal deformation of the optical resonant cavity and its associated structures. This deformation has a particularly significant impact on the laser path, which may cause misalignment of optical components and beam deviation, ultimately increasing measurement errors. In addition, the zero bias performance of the laser gyro is easily disturbed by temperature changes, and ambient temperature fluctuations often lead to zero bias instability. In order to meet the strict requirements for zero bias stability in high-precision application scenarios, the zero bias error needs to be controlled within an extremely low range, which poses a great challenge to the structural design of the laser gyro.

[0004] Existing studies have proposed improving the performance of laser gyroscopes by improving the thermal expansion properties of cavity materials and using temperature compensation. However, these methods will significantly increase the complexity and cost of the system and cannot meet the needs of cost-effective design in some special scenarios. At the same time, the influence of the geometric parameters of the core components of the laser gyroscope on its thermal deformation and overall performance has not been fully explored, and parametric design optimization is still in the exploratory stage.

[0005] Although there are many methods for designing the geometric structure of laser gyroscopes, these methods still encounter many difficulties in the actual design process. For example, the laser gyroscope jitter mechanism can only be optimized and designed based on engineering experience according to the influence of different parameters. Although the finite element method can be used for calculation and design, it requires continuous trial and error, and relies too much on computer computing power, which greatly increases the design cycle and in disguise increases the design cycle of the overall equipment. This has strong limitations for the large-scale application of high-precision pointing equipment in the future.

[0006] Therefore, it is necessary to provide a new dual-frequency machine-dithered laser gyroscope geometric structure optimization design method based on response surface methodology to solve the above technical problems. Summary of the invention

[0007] The technical problem solved by the present invention is to provide a geometric structure optimization design method for a two-frequency mechanically dithered ring laser gyroscope based on the response surface method, which can optimize and shorten the design cycle of the gyroscope, effectively suppress thermal deformation, and optimize the overall performance.

[0008] To solve the above technical problem, the geometric structure optimization design method for a two-frequency mechanically dithered ring laser gyroscope based on the response surface method provided by the present invention includes the following steps:

[0009] S1: Perform parametric modeling on the two-frequency mechanically dithered ring laser gyroscope, import its three-dimensional model into the ANSYS Workbench software to carry out thermal-structural analysis, and determine the thermal deformation of the optical resonator of the ring laser gyroscope.

[0010] S2: Use the central composite design method to construct a response surface model. Through experimental design of the combination of input parameters and output parameters, obtain the performance data of the ring laser gyroscope under different parameter combinations, and then fit to obtain the response surface model of the maximum thermal deformation of the cavity.

[0011] S3: According to the established response surface model, use the optimization method of MOGA to solve the optimal design parameters of the geometric structure of the two-frequency mechanically dithered ring laser gyroscope. Taking the minimum value of the maximum thermal deformation of the cavity as the optimization goal, seek the global optimal solution set through iteration to obtain multiple candidate solution sets.

[0012] Preferably, in the S1, the following steps are specifically included:

[0013] S11: Carry out finite element modeling of the ring laser gyroscope, complete parametric modeling and material parameter setting.

[0014] S12: Carry out working condition setting and thermal-structural simulation calculation and solution.

[0015] S13: Post-process the simulation results. After the solution is completed, read the thermal deformation results of the gyroscope cavity, obtain the maximum value of the simulated thermal deformation, click in the box in front of the maximum value of the thermal deformation to display the character P, and set it as the output parameter.

[0016] Preferably, in the S11, specifically, referring to the geometric dimensions of the real ring laser gyroscope, establish the structural model of the gyroscope in the Solidworks software, set the key structural dimensions as parameters, import the model into the ANSYS Workbench software, select the linkage of the steady-state thermal analysis and static structure modules, refer to the materials used in the real ring laser gyroscope, set the material parameters of each component of the gyroscope in the Engineering Data of the steady-state thermal analysis module, edit the geometric structure in the DesignModeler, click in the box in front of the above key structural dimensions to display the character P, and set it as the input parameter.

[0017] Preferably, in S12, when entering the steady-state thermal analysis module, select the materials corresponding to each component in Geometry; set the connection relationships between each component in Connections. The connection method between the gyro cavity and the dithering mechanism is set to the bonded method, the connection method between the dithering mechanism and the mounting box is set to the pre-tightening force method, and the connection at other places is adopted without separation; divide the finite element meshes of the dithering mechanism, mounting box, cavity, anode, slot piece, getter cover plate, frequency stabilization prism, adapter resistor, and gripper in the two-frequency mechanically dithered ring laser gyro in Mesh, and set the mesh size; apply boundary conditions in Steady-State Thermal. Set the gyro anode as internal heat generation, the gyro cavity gain area as heat flux, the outer surface of the gyro mounting box as convection, the side surface of the gyro cavity as convection, and the ambient temperature as room temperature 25°C; select Temperature in Solution and click Solve to perform the solution; apply boundary conditions in Static Structure, that is, set the bottom surface of the gyro mounting box as a fixed support constraint; select the import load command in the imported geometry temperature option and import the temperature field data into the static structure solver; select Total Deformation in Solution, select the geometric structure as the gyro cavity, and click Solve to perform the solution.

[0018] Preferably, in S2, it specifically includes the following steps:

[0019] S21: Select Response Surface Optimization under Design Exploration in the left toolbox on the Workbench main interface. Set the variable types of the input parameters and output parameters as continuous in the experimental design of the response surface optimization project, as well as the upper and lower limits of each parameter, and set the experimental design type as central composite design; click the update button above the window to solve the generated design points;

[0020] S22: Set the response surface type as the neural network algorithm in the response surface of the response surface optimization project, set the response mode as 2D, set the X-axis as each input parameter, and the Y-axis as the maximum thermal deformation of the cavity, and obtain the 2D curve relationship between the corresponding design points and the maximum thermal deformation of the cavity in the response table.

[0021] Preferably, in S2, it specifically includes the following steps:

[0022] S31: Set the optimization method as MOGA in the optimization of the response surface optimization project, set the initial sample number, the sample number for each iteration, the maximum number of iterations, and the maximum number of candidates; define the objectives and constraints in Objectives and Constraints, that is, define the maximum thermal deformation value of the cavity as the minimum;

[0023] S32: Click "Update" to perform calculations. View the optimized design results in "Results - Candidate Points". Comprehensively analyze the results of multiple candidate solution sets. To achieve the optimal performance of the geometric structure of the two-frequency mechanically dithered ring laser gyro, select one solution set as the final structural optimization parameters.

[0024] Compared with related technologies, the optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method provided by the present invention has the following beneficial effects:

[0025] The present invention provides an optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method. Using this optimized design method can effectively shorten the design cycle of the gyro, and effectively suppress the thermal deformation of the cavity and optimize the overall performance, having good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flowchart of the optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method provided by the present invention;

[0027] Figure 2 is a schematic diagram of the geometric parameters of the key structural dimensions of the laser gyro in the optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method provided by the present invention;

[0028] Figure 3 is a 2D curve relationship diagram of the design points and the maximum thermal deformation of the cavity in the optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described below with reference to the drawings and embodiments.

[0030] Please refer to Figure 1 、 Figure 2 and Figure 3 , where Figure 1 is a flowchart of the optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method provided by the present invention; Figure 2 is a schematic diagram of the geometric parameters of the key structural dimensions of the laser gyro in the optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method provided by the present invention; Figure 3 is a 2D curve relationship diagram of the design points and the maximum thermal deformation of the cavity in the optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method provided by the present invention. The optimized design method for the geometric structure of a two-frequency mechanically dithered ring laser gyro based on the response surface method includes the following steps:

[0031] 1) Parametrically model the two-frequency dither laser gyroscope, import its 3D model into ANSYS Workbench software to conduct thermal-structural analysis, and determine the thermal deformation of the optical resonator of the laser gyroscope. The specific process is as follows:

[0032] 1.1) Conduct finite element modeling of the laser gyroscope, and complete parametric modeling and material parameter setting;

[0033] Refer to the geometric dimensions of the real laser gyroscope, establish the structural model of the gyroscope in Solidworks software, and set the key structural dimensions as parameters, such as Figure 2 shown (the diameter D of the central hole of the optical resonator, the height H of the contact surface between the dither structure and the inner wall of the cavity, the outer wall thickness h of the dither structure, the width b of the support spoke p , and the depth l of the spoke groove c , width b c and the distance l from the center point p etc. are key structural dimensions). Import the model into ANSYS Workbench software, select the steady-state thermal analysis and static structure modules to be linked, and refer to the materials used in the real laser gyroscope, including super-invar alloy, microcrystalline glass, 7075-T6, etc. Set the material parameters of each component of the gyroscope, such as density, specific heat, thermal conductivity, etc. in the Engineering Data of the steady-state thermal analysis module. The material parameters can refer to the literature "Inertial Technology Handbook / Edited by Yang Lixi.—Beijing: China Astronautic Publishing House, December 2013". Edit the geometric structure in DesignModeler, click in the square box in front of the above key structural dimensions to display the P character, and set it as an input parameter.

[0034] 1.2) Conduct working condition setting and thermal-structural simulation calculation and solution;

[0035] Enter the steady-state thermal analysis module. Select the materials corresponding to each component in Geometry; set the connection relationships between each component in Connections. The connection method between the gyro cavity and the dithering mechanism is set to the bonded method, and the connection method between the dithering mechanism and the mounting box is set to the pre-tightening force method. The connections at other locations (including the connections between the piezoelectric ceramics and the spokes, the anode and the gyro body, the slot piece and the gyro body, the getter cover and the gyro body, the flat piece and the gyro body, the flat piece and the beam combining prism, the flat piece and the frequency stabilizing prism, the gripper and the cavity, the adapter resistor and the cavity) adopt the non-separation method; divide the finite element meshes of the dithering mechanism, the mounting box, the cavity, the anode, the slot piece, the getter cover, the frequency stabilizing prism, the adapter resistor, and the gripper in the two-frequency dithered ring laser gyro in Mesh, and set the mesh size; apply boundary conditions in Steady-State Thermal. Set the gyro anode to internal heat generation, with a magnitude of 240 W / m3. Set the gain area of the gyro cavity to heat flux, with a magnitude of 0.588 W. Set the outer surface of the gyro mounting box to convection, with a film coefficient of 5 W / m2·°C. Set the side surface of the gyro cavity to convection, with a film coefficient of 7 W / m2·°C. Set the ambient temperature to room temperature of 25°C; select Temperature in Solution and click Solve to perform the solution; apply boundary conditions in Static Structure, that is, set the bottom surface of the gyro mounting box to a fixed support constraint; select the "Import Load" command in the imported "Geometry Temperature" option to import the temperature field data into the static structure solver; select Total Deformation in Solution, select the geometric structure as the gyro cavity, and click Solve to perform the solution.

[0036] 1.3) Post-process the simulation results. After the solution is completed, read the thermal deformation results of the gyro cavity to obtain the maximum simulated thermal deformation value. Click in the box in front of the maximum thermal deformation value to display the character P, and set it as the output parameter.

[0037] 2) Use the central composite design (CCD) method to construct a response surface model. Through the experimental design of the combination of input parameters and output parameters, obtain the performance data of the ring laser gyro under different parameter combinations, and then fit to obtain the response surface model of the maximum thermal deformation of the cavity; the specific process is as follows:

[0038] 2.1) Select "Response Surface Optimization" under Design Exploration in the left toolbox on the main Workbench interface. In the "Design of Experiments (DOE)" in the response surface optimization project, set the variable types of the input and output parameters to continuous, and set the upper and lower limits of each parameter (the range of the central hole diameter of the optical resonator is 1 mm ≤ D ≤ 2.5 mm, the range of the contact surface height between the dither structure and the inner wall of the cavity is 2 mm ≤ H ≤ 10 mm, the range of the outer wall thickness of the dither structure is 1 ≤ h p ≤ 3, the range of the width of the support spoke is 0.4 ≤ b c ≤ 1.4, and the range of the depth of the spoke groove is 1 ≤ l c ≤ 8, the range of the width is 0.5 ≤ b p ≤ 0.7, and the range of the distance from the center point is 8 ≤ l

[0039] ≤ 12), and set the experimental design type to central composite design; click the "Update" button above the window to solve the generated design points. Figure 3 as shown

[0040] 3) According to the established response surface model, use the optimization method of MOGA to solve the optimal design parameters of the geometric structure of the two-frequency mechanically dithered laser gyro. Take the minimum value of the maximum thermal deformation of the cavity as the optimization goal, and seek the global optimal solution set through iteration to obtain 3 candidate solution sets; the specific process is as follows:

[0041] 3.1) In the "Optimization" in the response surface optimization project, set the optimization method to MOGA, set the initial sample number to 1000, the sample number for each iteration to 1000, the maximum number of iterations to 50, and the maximum number of candidates to 3; define the objectives and constraints in the "Objectives and Constraints", that is, define the maximum thermal deformation value δ of the cavity max and select Minimize in the Type column under it.

[0042] 3.2) Click "Update" to perform the calculation, view the optimization design results in the "Results - Candidate Points", comprehensively analyze the results of the 3 candidate solution sets, as shown in Table 1, and select Solution Set 2 as the final structural optimization parameters to achieve the optimal performance of the geometric structure of the two-frequency mechanically dithered laser gyro.

[0043] Table 1 Structural Optimization Results

[0044]

[0045] Compared with the related technologies, the geometric structure optimization design method of the two-frequency mechanically dithered ring laser gyroscope based on the response surface method provided by the present invention has the following beneficial effects:

[0046] The present invention provides a geometric structure optimization design method of a two-frequency mechanically dithered ring laser gyroscope based on the response surface method. By using this optimization design method, the design cycle of the gyroscope can be effectively shortened, the effective suppression of the cavity thermal deformation and the optimization of the overall performance can be realized, and it has good engineering application value.

[0047] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A geometric structure optimization design method for a dual-frequency machine-shaking laser gyro based on response surface methodology, characterized in that: The following steps are involved: S1: Parametric modeling of the dual-frequency machine-shaking laser gyro was performed, and its three-dimensional model was imported into ANSYS Workbench software for thermal-structural analysis to determine the thermal deformation of the laser gyro's optical resonator; S2: The response surface model is constructed by using the central composite design method. By conducting experimental design on the input and output parameter combinations, the performance data of the laser gyro under different parameter combinations are obtained, and then the response surface model of the maximum thermal deformation of the cavity is fitted; S3: Based on the established response surface model, the MOGA optimization method is used to solve the optimal design parameters of the geometric structure of the dual-frequency machine-shake laser gyroscope. The minimum maximum thermal deformation value of the cavity is taken as the optimization goal. The global optimal solution set is sought through iteration to obtain multiple candidate solution sets.

2. The geometric structure optimization design method of the dual-frequency machine-shake laser gyro based on the response surface method according to claim 1 is characterized in that: The S1 specifically includes the following steps: S11: Perform finite element modeling of the laser gyro, complete parametric modeling and material parameter setting; S12: Perform working condition setting and thermal-structural simulation calculation and solution; S13: Post-process the simulation results. After the solution is completed, read the thermal deformation results of the gyro cavity to obtain the maximum thermal deformation value δ of the simulation. max , click in the box in front of the maximum value of thermal deformation to make the P character appear and set it as the output parameter.

3. The geometric structure optimization design method of the dual-frequency machine-shake laser gyro based on the response surface method according to claim 2 is characterized in that: In the S11, specifically, referring to the geometric dimensions of a real laser gyroscope, establishing a structural model of the gyroscope in the Solidworks software, setting key structural dimensions as parameters, importing the model into the ANSYS Workbench software, selecting the steady-state thermal analysis and static structural module linkage, referring to the materials used in the real laser gyroscope, setting the material parameters of each component of the gyroscope in the Engineering Data of the steady-state thermal analysis module, editing the geometric structure in DesignModeler, clicking the P character in the box in front of the above-mentioned key structural dimensions, and setting it as an input parameter.

4. The geometric structure optimization design method of the dual-frequency machine-shaking laser gyro based on the response surface method according to claim 2 is characterized in that: In the S12, enter the steady-state thermal analysis module, select the material corresponding to each component in Geometry; set the connection relationship between each component in Connections, set the connection mode between the gyro cavity and the shaking mechanism to binding mode, set the connection mode between the shaking mechanism and the mounting box to preload mode, and use the non-separation mode for other connections; divide the finite element mesh of the shaking mechanism, mounting box, cavity, anode, slot, getter cover, frequency stabilization prism, adapter resistor, and gripper in the dual-frequency machine shaking laser gyro in Mesh, and set the mesh size; apply boundary conditions in Steady-State Thermal, set the gyro anode to internal heat generation, the gyro cavity gain zone to heat flow, the outer surface of the gyro mounting box to convection, the side of the gyro cavity to convection, and the ambient temperature to room temperature 25°C; select Temperature in Solution, click Solve to solve; in Static Apply boundary conditions in Structure, that is, set the bottom surface of the gyro mounting box as a fixed support constraint; select the Import Load command in the Imported Geometry Temperature option to import the temperature field data into the static structural solver; select Total Deformation in Solution, select the geometric structure as the gyro cavity, and click Solve to solve.

5. The geometric structure optimization design method of dual-frequency machine-shake laser gyro based on response surface methodology according to claim 1 is characterized in that: The S2 specifically includes the following steps: S21: In the main interface of Workbench, select Response Surface Optimization under Design Exploration in the left toolbox. In the experimental design of the response surface optimization project, set the variable type of input parameters and output parameters to continuous, as well as the upper and lower limits of each parameter, and set the experimental design type to central composite design. Click the Update button at the top of the window to solve the generated design points. S22: In the response surface of the response surface optimization project, the response surface type is set to the neural network algorithm, the response mode is set to 2D, the X-axis is set to each input parameter, and the Y-axis is set to the maximum thermal deformation of the cavity. In the response table, the 2D curve relationship between the corresponding design point and the maximum thermal deformation of the cavity is obtained.

6. The geometric structure optimization design method of dual-frequency machine-shake laser gyro based on response surface methodology according to claim 1 is characterized in that: The S2 specifically includes the following steps: S31: In the optimization of the response surface optimization project, set the optimization method to MOGA, set the initial sample number, the number of samples for each iteration, the maximum number of iterations, and the maximum number of candidates; define the objectives and constraints in the objectives and constraints, that is, define the maximum thermal deformation value of the cavity to be the minimum; S32: Click Update to perform calculations, view the optimization design results in Results-Candidate Points, and comprehensively analyze the results of multiple candidate solution sets. In order to achieve the optimal performance of the dual-frequency machine-shake laser gyroscope geometric structure, select one of the solution sets as the final structural optimization parameters.

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