A method for optimizing the back frame and transition structure of a submillimeter-wave antenna

Abstract

The present invention discloses a submillimeter wave antenna back frame and transition structure optimization method, including: designing an initial model of the back frame structure; establishing an initial topology optimization model of the submillimeter wave antenna transition structure; performing static analysis on the initial topology optimization model and post-processing the analysis results, extracting required parameters to establish a corresponding optimization model; using the super-element method to compress the antenna back frame and its main panel particle units into interface nodes, and importing the compressed finite element model into the topology optimization module of Workbench; using the workbench optimization module to perform distributed optimization, output the optimization results, and obtain the optimal solution model; performing static analysis on the optimal solution model. The present invention can improve the structural rigidity as much as possible under the action of gravity to reduce the influence of gravity on the antenna surface accuracy, and obtain the optimal solution that satisfies the minimum antenna surface error.

Description

Technical Field

[0001] The present invention relates to the technical field of the design and optimization of large-scale precision antenna backbones and transition structures, and more particularly to an optimization method for a submillimeter-wave antenna backbone and a transition structure. Background Art

[0002] The submillimeter-wave band is a new window for exploring the universe. In recent years, countries around the world have successively planned and constructed the next-generation large-aperture and high-precision submillimeter-wave telescope antennas, including the CCAT (25m) in the United States, the LST (50m) in Japan, the AtLAST (50m) in Europe, and so on. In recent years, the submillimeter-wave research group in China has also proposed the idea of a 60-meter-class submillimeter-wave telescope. Building the next-generation large-scale submillimeter-wave astronomical observation facilities has become a high consensus in the international astronomical community. For single-aperture millimeter-wave and submillimeter-wave antennas, in order to improve the sensitivity and resolution of the system, the required aperture of the antenna is increasing day by day. However, as the aperture increases, the structural self-weight of large-scale precision antennas usually shows exponential growth, which poses higher requirements for their structural stiffness. If the self-weight and stiffness are mismatched, not only will the natural frequency of the structure decrease, but also the structure will undergo serious deformation, which will seriously affect the reflector surface accuracy of the antenna. Therefore, when designing the structure of a large-aperture antenna, it is necessary to solve the problem of the mismatch between the structural self-weight and stiffness, and specifically propose improvement plans through conceptual optimization design to carry out the overall structure development of the antenna.

[0003] The 60m submillimeter-wave antenna is an advanced large-aperture and large-field-of-view submillimeter-wave telescope, with a main reflector aperture of 60m, a working wavelength covering 0.65 - 3mm, a designed field-of-view diameter of up to 1°, and very strict requirements for the reflector surface accuracy and pointing accuracy, requiring a surface shape accuracy better than 30μm and a tracking pointing accuracy better than 2 arcseconds, and requiring the accuracy to be maintained stably for a long time. However, for large-aperture antennas, in order to maintain the surface shape accuracy and pointing accuracy, the self-weight of the antenna and the large-span structural distribution will inevitably have an impact. Therefore, optimization design means should be used in the preliminary structural design stage to reduce these impacts.

[0004] After the structural design of high-precision large-aperture submillimeter-wave telescopes is completed, active surface technology is often used to correct the influence of gravity deformation on the main surface accuracy. However, the correction accuracy range is limited, and a certain design accuracy needs to be achieved during the preliminary design to ensure that the active surface technology used later can meet the accuracy requirements. At present, the back frame design of the antenna generally adopts a shape-preserving design, but the transition structure design is a major difficulty. At present, there are probably the following types: For example, the 10mHHT millimeter-wave telescope uses a transition structure design of cross steel sheets to connect the CFRP back frame and the steel antenna base. This design can reduce the influence of thermal deformation on structural accuracy, but it will make the telescope structure seriously insufficient in rigidity, so it is not suitable for large-aperture radio telescopes. The 25mCCAT submillimeter-wave telescope planned to be built in the United States is going to use a CFRP back frame structure, and based on the thermal shape-preserving theory, a space truss transition structure design is proposed, which needs further research and verification. The 50mLMT millimeter-wave telescope adopts a transition structure design in which a dual drive shaft is directly connected to a steel back frame. The connection points are symmetrically distributed at the four connection positions on the 45° plane of the bottom layer of the back frame. The optical field of view and main surface accuracy requirements of this telescope are lower than those of the 60m submillimeter-wave antenna, but its structural design can be used as a design reference for the 60m submillimeter-wave telescope. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a submillimeter wave antenna back frame and transition structure optimization method, which can improve the structural stiffness as much as possible under the action of gravity to reduce the influence of gravity on the antenna surface accuracy, and obtain the optimal solution that satisfies the minimum antenna surface error.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A submillimeter wave antenna back frame and transition structure optimization method, the optimization method comprising the following steps:

[0008] S1, based on the main panel design of the 60m submillimeter wave antenna, the initial model of the back frame structure is designed using the conformal principle; according to the topology optimization principle, the initial topology optimization model of the 60m submillimeter wave antenna transition structure is established; static analysis is performed on the initial topology optimization model and the analysis results are post-processed to extract the required parameters and establish the corresponding optimization model;

[0009] S2, the super-element method is used to compress the antenna back frame and its main panel mass point elements into interface nodes, and the compressed finite element model is imported into the topology optimization module of Workbench. The constructed optimization model is:

[0010] find x=[x1,x2,……,x n ] T

[0011] Minimize \(C(x)=F\) T \(U(x)\)

[0012] Subject to \(v(x)=x\) T \(v - V^*\leq0\)

[0013] \(f\geq f\) l

[0014] \(x\in\chi,\chi = \{x\in R\) n , 0\leq x\leq1\}

[0015] where \(x\) i is the topological density variable assigned to each element. The objective function is the total structural compliance \(C(x)\); \(n\) is the total number of elements in the optimization domain, \(F\) is the nodal load vector, \(U(x)\) is the displacement vector of the structure, \(v(x)\) is the optimized volume, \(V^*\) is the volume constraint, \(f,f\) l are the natural frequency and the lower limit of the natural frequency of the structure, respectively;

[0016] S3. Use the workbench optimization module to perform distributed optimization, output the optimization results, and obtain the optimal solution model; perform a static analysis on the optimal solution model.

[0017] 2. According to the method for optimizing the sub - millimeter - wave antenna back - frame and transition structure as claimed in claim 1, characterized in that in step S3, the process of using the workbench optimization module to perform distributed optimization includes the following steps:

[0018] S31. Select the reference point coordinates of the back - frame as the optimization variables, and the root - mean - square error \(rmse\) of the geometric deformation of the main surface of the antenna pointing to the zenith as the objective function. Use the Genetic Aggregation response surface method in the Workbench optimization module to perform experimental analysis on the objective function. The analysis model is as follows:

[0019]

[0020]

[0021]

[0022]

[0023] where \(r\) j is the design variable of the \(j\) - th design point, \(N\) M is the number of models used, \(w\) k is the weight factor of the \(k\) - th iteration response, \(y(r\) j ) and are the output response and response prediction of the \(k\) - th iteration respectively, is the response prediction of the overall structure, Prediction of the overall structural response without the j-th design point; by minimizing the root mean square error of the design experimental points and the root mean square error based on cross-validation to obtain the optimal weight values, that is, the sensitivity results of each design variable;

[0024] S32, select the backframe coordinate parameters with high sensitivity as the optimization independent variables, take the effective error rmse of the antenna main surface deformation pointing downward as the objective function, and determine the value range of the design variables according to the spatial position of the backframe members; use the genetic algorithm of the Workbench optimization module for optimization, and the optimization model constructed is:

[0025] min rmse

[0026]

[0027]

[0028] zcen l ≤zcen≤zcen u

[0029] where x pq , z pq respectively represent the x and z axis coordinates of the reference point of the backframe in the main surface cylindrical coordinate system, p and q are the number of layers and rings of the backframe respectively, p = 1, 2,..., 4; q = 1, 2,..., 7, are the upper and lower limits of x pq respectively, are the upper and lower limits of z pq respectively, zcen l , zcen u are the upper and lower limits of the overall structural center of gravity position zcen respectively; after obtaining the optimization results, substitute the parameter results to re-establish the model required for the second-step optimization;

[0030] S33, select the cross-sectional parameters of the backframe and the transition structure as the optimization independent variables, and take the effective error rmse of the antenna main surface deformation pointing downward and the center of gravity position as the objective functions; use the multi-objective genetic algorithm of the Workbench optimization module for optimization, and the optimization model constructed is:

[0031] minΠ(rmse,zcen)

[0032]

[0033]

[0034]

[0035]

[0036] where rbs m and tbs m represent the outer diameter and thickness of the back frame members respectively, m is the number of back frame member types, m = 1, 2, …, 5, and are the upper and lower limits of rbs m and tbs m respectively. rts n and tts n represent the outer diameter and thickness of the transition structure members respectively, n is the number of transition structure member types, n = 1, 2, 3, and are the upper and lower limits of rts n and tts n respectively. After obtaining the optimization results, substitute the parameter results to re - establish the model required for the third - step optimization;

[0037] S34, select the spatial positions of different component interfaces as the optimization independent variables, and take the effective error rmse of the antenna main surface deformation pointing downward to the zenith and the center - of - gravity position zcen as the objective functions; use the multi - objective genetic algorithm of the Workbench optimization module for optimization. The constructed optimization model is:

[0038] minΠ(rmse,zcen)

[0039]

[0040]

[0041]

[0042]

[0043] where z 41 and z 43 are the coordinate values corresponding to the reference points at the bottom layer of the back frame, is the lower and upper limits corresponding to z 41 and z 43 respectively. h1 represents the height of the driving wheel connection platform, represents the lower and upper limits of h1, t c is the thickness of the driving wheel steel plate, and c is the number of driving wheel steel plate thickness types, c = 1, 2, 3.

[0044] S35, output the results after optimization. The output data includes the optimal solution, constraint variables, and design variables.

[0045] Furthermore, the antenna back frame of the 60m submillimeter-wave antenna is made of CFRP material rods.

[0046] Furthermore, the transition structure and drive wheels of the 60m submillimeter-wave antenna are made of steel materials.

[0047] In the back frame and transition structure designed by the present invention, the super element method is used to compress the back frame into a super element at the interface node position, and then the topology optimization method is used to simplify the annular solid transition structure into a space truss structure with good stiffness. The parametric modeling analysis of the antenna structure is carried out by using APDL. The back frame and transition structure are optimized by using the multi-objective genetic algorithm by calling the optimization module of ANSYS Workbench, so that the main surface shape of the antenna is optimal under the action of gravity while balancing the center of gravity position of the antenna, and the final design result is obtained. The present invention can improve the structural stiffness as much as possible under the action of gravity to reduce the influence of gravity on the surface shape accuracy of the antenna. Based on the conformal design of the back frame, the initial design of the transition structure is obtained through topology optimization, and the optimal solution that minimizes the antenna surface shape error is obtained through the genetic algorithm.

[0048] The beneficial effects of the present invention are as follows:

[0049] (1) Parameter modeling and analysis are carried out by using APDL, and key variables such as model size and material properties are parameterized for easy viewing and modification.

[0050] (2) The topology optimization method is adopted to ensure the stiffness of the antenna transition structure and effectively reduce the influence of structural gravity deformation on the antenna surface type accuracy.

[0051] (3) The sensitivity of parameters can be analyzed and optimized by using the test analysis results of ANSYS, and then the genetic algorithm of the Workbench optimization module is called to optimize the parameters of the overall model, improving the accuracy of structural optimization design.

[0052] (4) Each iteration variable and result in the optimization process can be viewed, and the final output data includes the optimal solution, constraint variables and design variables.

[0053] (5) This method is applicable to the design and optimization of the back frame and transition structure of large submillimeter-wave antennas, and the optimization process and optimization variables can be selected according to specific designs. Description of the Drawings

[0054] Figure 1 is the flow chart of the optimization method for the back frame and transition structure of the submillimeter-wave antenna in the embodiment of the present invention.

[0055] Figure 2 is the schematic diagram of the topology optimization design of the antenna transition structure in the embodiment of the present invention; wherein, Figure 2(a) Schematic diagram of the initial design for topology optimization, Figure 2 (b) Schematic diagram of the final design for topology optimization.

[0056] Figure 3 It is a schematic diagram of the topology optimization process of the transition structure in an embodiment of the present invention.

[0057] Figure 4 It is a schematic diagram of the test analysis results of the reference point coordinates of the back frame in an embodiment of the present invention.

[0058] Figure 5 It is a schematic diagram of the optimization iteration process of the genetic algorithm in an embodiment of the present invention; wherein, Figure 5 (a) Schematic diagram of the optimization of the reference point coordinates of the back frame, Figure 5 (b) Schematic diagram of the optimization of the cross-sectional parameters of the rod member, Figure 5 (c) Schematic diagram of the optimization of the spatial position parameters of the interface surface. Detailed implementation manners

[0059] Now, the present invention will be further described in detail with reference to the accompanying drawings.

[0060] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "rear", etc. cited in the invention are only for the convenience of clear description, rather than to limit the scope of implementation of the present invention. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0061] Figure 1 It is a flowchart of the optimization method for the submillimeter-wave antenna back frame and transition structure in an embodiment of the present invention. Refer to Figure 1 , and this optimization method includes the following steps:

[0062] S1. According to the design of the main panel of the 60m submillimeter-wave antenna, design the initial model of the back frame structure using the conformal principle; according to the topology optimization principle, establish the initial topology optimization model of the 60m submillimeter-wave antenna transition structure; conduct static analysis on the initial topology optimization model and post-process the analysis results to extract the required parameters and establish the corresponding optimization model.

[0063] S2. Use the super element method to compress the back frame of the antenna and its main panel mass point elements into interface nodes, and import the compressed finite element model into the topology optimization module of Workbench. The constructed optimization model is:

[0064] find x=[x1,x2,……,x n T

[0065] min C(x)=F T U(x) ​

[0066] such that \(v(x)=x\) T \(v - V^*\leq0\)

[0067] \(f\geq f\) l

[0068] \(x\in\chi,\chi = \{x\in R\) n , \(0\leq x\leq1\}\)

[0069] where \(x\) i is the topological density variable assigned to each element, the objective function is the total structural compliance \(C(x)\); \(n\) is the total number of elements in the optimization domain, \(F\) is the nodal load vector, \(U(x)\) is the displacement vector of the structure, \(v(x)\) is the optimized volume, \(V^*\) is the volume constraint, \(f,f\) l are the natural frequency and the lower limit of the natural frequency of the structure respectively.

[0070] S3. Use the workbench optimization module to perform distributed optimization, output the optimization results, and obtain the optimal solution model; perform static analysis on the optimal solution model.

[0071] The purpose of the present invention is to improve the structural stiffness as much as possible under the action of gravity to reduce the influence of gravity on the surface shape accuracy of the antenna. Therefore, an optimization design method for the antenna back frame and transition structure based on topology optimization and genetic algorithm is proposed. Based on the shape-preserving design of the back frame, the initial design of the transition structure is obtained through topology optimization, and the optimal solution that satisfies the minimum antenna surface shape error is obtained through genetic algorithm. The specific design process is as follows:

[0072] (1) According to the design of the main panel of the 60m submillimeter wave antenna, the initial model of the back frame structure is designed by using the shape-preserving principle. According to the topology optimization principle, the initial topology optimization model of the 60m submillimeter wave antenna transition structure is established. After establishing the overall model, perform static analysis on it and post-process the analysis results to extract the required parameters to establish the optimization model.

[0073] (2) Considering that there are a large number of non-optimization domain elements in the finite element model, first use the super-element method to compress the back frame of the antenna and its main panel mass point elements into interface nodes to reduce the scale of optimization iteration calculation. Then import the compressed finite element model into the topology optimization module of Workbench, and the established optimization model is:[[]]

[0074] find \(x = [x_1,x_2,\cdots,x\) n T

[0075] min \(C(x)=F\) T \(U(x)\)

[0076] such that \(v(x)=x\) T \(v - V^*\leq0\) ​

[0077] f ≥ f l

[0078] x ∈ χ, χ = {x ∈ R n , 0 ≤ x ≤ 1}

[0079] where x i is the topological density variable assigned to each element, the objective function is the total compliance C(x); n is the total number of elements in the optimization domain, F is the nodal load vector, U(x) is the displacement vector of the structure, v(x) is the optimized volume, V* is the volume constraint, f and f l are the natural frequency and the lower limit of the natural frequency of the structure respectively. After optimizing the model using the variable density method, the optimized model results are derived, converted into an optimizable space truss structure, and a parametric finite element model is established for multi-step optimization.

[0080] (3) Select the reference point coordinates of the back frame as the optimization variables, and the root mean square error rmse of the geometric deformation of the main surface of the zenith-pointing antenna as the objective function. First, conduct an experimental analysis on the objective function. The analysis method is the Genetic Aggregation response surface method in the Workbench optimization module. The analysis model is as follows:

[0081]

[0082]

[0083]

[0084]

[0085] where, r j is the design variable of the j-th design point, N M is the number of models used, w k is the weight factor of the k-th iteration response, y(r j ) and are the output response and response prediction of the k-th iteration respectively, is the response prediction of the overall structure, is the response prediction of the overall structure without the j-th design point; by minimizing the root mean square error of the design experimental points and the root mean square error based on cross-validation, the optimal weight value, that is, the sensitivity results of each design variable, are obtained.

[0086] Select the backframe coordinate parameters with high sensitivity as the optimization independent variables, take the effective error rmse of the antenna main surface deformation with the zenith pointing down as the objective function, and determine the value range of the design variables according to the spatial positions of the backframe members. Use the genetic algorithm of the Workbench optimization module for optimization. The optimization model constructed thereby is:

[0087] min rmse

[0088]

[0089]

[0090] zcen l ≤zcen≤zcen u

[0091] where x pq 、z pq respectively represent the x and z axis coordinates of the reference point of the backframe in the main surface cylindrical coordinate system, p and q are respectively the number of backframe layers and the number of rings, p = 1, 2,..., 4; q = 1, 2,..., 7, are respectively the upper and lower limits of x pq , are respectively the upper and lower limits of z pq , zcen l 、zcen u are respectively the upper and lower limits of the overall structure gravity center position zcen; After obtaining the optimization results, substitute the parameter results to re - establish the model required for the second - step optimization.

[0092] (4) Select the cross - section parameters of the backframe and transition structure (including the outer diameter and thickness of the members) as the optimization independent variables, take the effective error rmse of the antenna main surface deformation with the zenith pointing down and the gravity center position as the objective function. Use the multi - objective genetic algorithm of the Workbench optimization module for optimization. The optimization model constructed thereby is:

[0093] minΠ(rmse,zcen)

[0094]

[0095]

[0096]

[0097]

[0098] where rbs m 、tbs m respectively represent the outer diameter and thickness of the backframe members, m is the number of backframe member types, m = 1, 2,..., 5, and are the upper and lower limits of rbs m , tbs m respectively. rts n , tts n represent the outer diameter and thickness of the transition structure rod respectively. n is the number of types of transition structure rods, n = 1, 2, 3. and are the upper and lower limits of rts n , tts n respectively. After obtaining the optimization results, substitute the parameter results and re - establish the model required for the third - step optimization.

[0099] (5) Select the spatial positions of different component interfaces as the optimization independent variables, and use the effective error rmse of the deformation of the main surface of the antenna pointing downward and the center - of - gravity position zcen as the objective functions. Use the multi - objective genetic algorithm of the Workbench optimization module for optimization. The optimization model constructed is:

[0100] minΠ(rmse,zcen)

[0101]

[0102]

[0103]

[0104]

[0105] where z 41 and z 43 are the coordinate values corresponding to the reference points at the bottom layer of the back frame. is the lower and upper limits corresponding to z 41 and z 43 respectively. h1 represents the height of the driving - wheel connection platform. represents the lower and upper limits of h1. t c is the thickness of the driving - wheel steel plate. c is the number of types of driving - wheel steel - plate thicknesses, c = 1, 2, 3. Output the results after optimization.

[0106] (6) According to the optimization results, establish an antenna model based on the optimal results and analyze the whole antenna.

[0107] Taking the 60 - m - diameter sub - millimeter - wave antenna as an example, the back frame of the antenna uses CFRP material rods, the transition structure and the driving wheel use steel materials. Use the topology optimization method to design the antenna transition structure. The models before and after the design are as Figure 2As shown, the area pointed by the arrow is the optimization area of the transition structure. This part is first simplified into an annular solid structure, and through the topology optimization process and conversion, the final design structure is obtained. The optimization process is as Figure 3 shown.

[0108] According to the optimization model established in step (2), taking the root mean square error (rmse) of the geometric deformation of the main surface of the antenna as the main objective function, first perform a sensitivity analysis of the reference coordinates of the backframe joints in step (3). The analysis results are as Figure 4 shown. In the optimization process of steps (4) and (5), add the position of the center of gravity of the structure zcen as a secondary target parameter. The optimization process uses the reference coordinates of the backframe joints, the cross-sectional parameters of the backframe and the transition structure rods, and the interface position as design variables, and performs genetic algorithm optimization on the designed structure step by step. Output the objective function and the values of the design variables corresponding to the optimal results of each step to establish the optimization parameter model for the next step. Extract the data from the output file to obtain the iterative process of the objective function rmse and the position of the center of gravity of the structure zcen, as Figure 5 shown.

[0109] Finally, the optimal solution is obtained when the maximum number of generations of evolution is reached and the algorithm converges. That is, under the action of gravity, the geometric deformation error of the main surface of the antenna is 135.6 μm, and the center of gravity coordinate is 0.029 m. Compare the analysis results of the structures before and after optimization. Under the same gravity load, the deformation error of the main surface of the antenna is reduced by 61.1%, and the center of gravity coordinate is very close to the ideal position. Compared with the optimization results of the reference LMT design structure, the deformation error of the main surface of the antenna is reduced by 48.3%, and the center of gravity coordinate is closer to the ideal position.

[0110] The above is only the preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. Any technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements should be regarded as within the protection scope of the present invention.

Claims

1. A method for optimizing the back frame and transition structure of a sub-millimeter wave antenna, characterized in that, The optimization method includes the following steps: S1. According to the design of the main panel of the 60m submillimeter-wave antenna, an initial model of the back frame structure is designed using the conformal principle; according to the topology optimization principle, an initial topology optimization model of the transition structure of the 60m submillimeter-wave antenna is established; static analysis is performed on the initial topology optimization model and post-processing is carried out on the analysis results to extract the required parameters and establish the corresponding optimization model; S2. The super-element method is used to compress the back frame of the antenna and its main panel mass point elements into interface nodes, and the compressed finite element model is imported into the topology optimization module of Workbench. The constructed optimization model is: find x=[x1,x2,……,x n T ​ min C(x) = F T U(x) such that v(x) = x T v - V* ≤ 0 f≥f l x ∈ χ, where χ = {x ∈ R n , 0 ≤ x ≤ 1} where x i is the topological density variable assigned to each element, and the objective function is the total structural compliance C(x); n is the total number of elements in the optimization domain, F is the nodal load vector, U(x) is the displacement vector of the structure, v(x) is the optimized volume, V* is the volume constraint, f, f l are the natural frequency and the lower limit of the natural frequency of the structure, respectively; S3. The workbench optimization module is used for distribution optimization, and the optimization results are output to obtain the optimal solution model; static analysis is performed on the optimal solution model.

2. The method for optimizing the back frame and transition structure of a sub-millimeter wave antenna according to claim 1, characterized in that, In step S3, the process of using the workbench optimization module for distribution optimization includes the following steps: S31. Select the reference point coordinates of the back frame as the optimization variable, and the root mean square error (rmse) of the geometric error of the main surface deformation of the antenna pointing to the zenith as the objective function. The Genetic Aggregation response surface method in the Workbench optimization module is used to perform experimental analysis on the objective function. The analysis model is as follows: where r j is the design variable of the j-th design point, N M is the number of models used, w k is the weight factor of the k-th iteration response, y(r j ) and are the output response and response prediction of the k-th iteration respectively, is the response prediction of the overall structure, is the response prediction of the overall structure without the j-th design point; by minimizing the root mean square error of the design experiment points and the root mean square error based on cross-validation, the optimal weight value, i.e., the sensitivity results of each design variable, is obtained; S32. Select the back frame coordinate parameters with high sensitivity as the optimization independent variables, and the effective error rmse of the main surface deformation of the antenna pointing to the zenith as the objective function. Determine the value range of the design variables according to the spatial position of the back frame members; use the genetic algorithm of the Workbench optimization module for optimization. The constructed optimization model is: min rmse zcen l ≤zcen≤zcen u where x pq , z pq respectively represent the x-axis and z-axis coordinates of the reference point of the backrest frame in the main plane cylindrical coordinate system, p and q are the number of layers and the number of rings of the backrest frame respectively, p = 1, 2, …, 4; q = 1, 2, …, 7, are respectively the upper and lower limits of x pq , are respectively the upper and lower limits of z pq , zcen l , zcen u are respectively the upper and lower limits of the zcen of the overall structure center of gravity position; after obtaining the optimization result, substitute the parameter result to re-establish the model required for the second-step optimization; S33. Select the cross-sectional parameters of the back frame and the transition structure members as the optimization independent variables, and the effective error rmse of the main surface deformation of the antenna pointing to the zenith and the center of gravity position as the objective functions; use the multi-objective genetic algorithm of the Workbench optimization module for optimization. The constructed optimization model is: minΠ(rmse,zcen) where rbs m and tbs m represent the outer diameter and thickness of the back frame member respectively, m is the number of back frame member types, m = 1, 2, …, 5, and are the upper and lower limits of rbs m and tbs m respectively, rts n and tts n represent the outer diameter and thickness of the transition structure member respectively, n is the number of transition structure member types, n = 1, 2, 3, and are the upper and lower limits of rts n and tts n respectively; after obtaining the optimization result, substitute the parameter result to re - establish the model required for the third - step optimization; S34. Select the spatial positions of different component interfaces as the optimization independent variables, and the effective error rmse of the main surface deformation of the antenna pointing to the zenith and the center of gravity position zcen as the objective functions; use the multi-objective genetic algorithm of the Workbench optimization module for optimization. The constructed optimization model is: minΠ(rmse,zcen) where z 41 and z 43 are the coordinate values corresponding to the reference points at the bottom layer of the backrest frame, for z 41 and z 43 the corresponding lower and upper limits, h1 represents the height of the driving wheel connection platform, represents the lower and upper limits of and h1, t c is the thickness of the driving wheel steel plate, c is the number of types of driving wheel steel plate thickness, c = 1, 2, 3; S35. After the optimization is completed, the results are output. The output data includes the optimal solution, constraint variables, and design variables.

3. The sub-millimeter wave antenna back frame and transition structure optimization method according to claim 1, characterized in that, The antenna back frame of the 60m submillimeter-wave antenna uses CFRP material rods.

4. The sub-millimeter wave antenna back frame and transition structure optimization method according to claim 1, characterized in that, The transition structure and drive wheel of the 60m submillimeter-wave antenna use steel materials.

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