Parameter optimization design method for stack satellite load-bearing cylinder

Abstract

The application discloses a method for optimizing the parameters of a stacked satellite force-carrying cylinder, which comprises the following steps: performing mechanical simulation on a stacked multi-satellite combination body to analyze the force-carrying cylinder parameters affecting the fundamental frequency k of the combination body; performing mechanical simulation on the force-carrying cylinder parameters with different values to obtain the corresponding fundamental frequency k of the combination body, and fitting a binary polynomial function about the force-carrying cylinder parameters and the fundamental frequency k of the combination body; selecting different values for the outer diameter d and the wall thickness h of the force-carrying cylinder to perform 3D model design and obtain the corresponding weight m; fitting a binary polynomial function about the force-carrying cylinder parameters and the weight m of the force-carrying cylinder; and establishing a force-carrying cylinder strength constraint function according to the allowable stress σ0 of the force-carrying cylinder material; the method optimizes the parameters of the stacked satellite force-carrying cylinder, takes the outer diameter and the wall thickness of the force-carrying cylinder as design variables, takes the fundamental frequency of the combination body and the strength of the force-carrying cylinder as constraint conditions, and takes the weight of the force-carrying cylinder as an optimization target.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite structure design, in particular to a method for optimizing parameters of a stacked satellite force-carrying cylinder. BACKGROUND

[0002] A low-orbit satellite internet constellation usually adopts a stacked multi-satellite assembly for launching, which can fully utilize the space of a launch vehicle fairing, improve launch efficiency, and reduce redundant weight without a dedicated satellite-launch vehicle adapter, thereby improving the carrying capacity. In the stacked configuration, satellites are connected to each other by force-carrying cylinders, and the structural parameters of the force-carrying cylinders affect both the fundamental frequency of the stacked multi-satellite assembly and the weight of the force-carrying cylinders, thereby affecting the weight of the satellite. If the fundamental frequency of the assembly is increased to ensure launch safety, the weight of the satellite will be increased, the launch cost will be increased, and the launch efficiency will be reduced. However, if the weight of the force-carrying cylinders is reduced, the fundamental frequency of the assembly will be reduced, the strength of the force-carrying cylinders will be reduced, and launch safety hazards will be caused. Therefore, it is of great significance to optimize the parameters of the force-carrying cylinders. SUMMARY

[0003] In view of the deficiencies in the prior art, the present application provides a method for optimizing parameters of a stacked satellite force-carrying cylinder, which aims to solve the problem that, in the prior art, when a designer designs a force-carrying cylinder structure, the requirements for the fundamental frequency of the assembly, the structural strength, and the lightweight are usually considered, and the weight of the force-carrying cylinder must be sacrificed to improve the fundamental frequency and the structural strength of the assembly, so that the optimal parameters of the force-carrying cylinder are difficult to be obtained.

[0004] To achieve the above object, the present application provides the following technical scheme:

[0005] The method for optimizing parameters of a stacked satellite force-carrying cylinder comprises the following steps:

[0006] Step S1: performing mechanical simulation on a stacked multi-satellite assembly to analyze the parameters of the force-carrying cylinders that affect the fundamental frequency k of the assembly;

[0007] Step S2: performing mechanical simulation on the force-carrying cylinders according to different values of the parameters to obtain the corresponding fundamental frequency k of the assembly, and fitting a binary polynomial function f k (d,h) about the parameters of the force-carrying cylinders and the fundamental frequency k of the assembly, i.e., a constraint function f k (d,h) = k0, wherein h is the wall thickness of the force-carrying cylinder, and d is the outer diameter of the force-carrying cylinder;

[0008] Step S3: performing 3D model design on the force-carrying cylinders according to different values of the outer diameter d and the wall thickness h of the force-carrying cylinders to obtain the corresponding weight m;

[0009] Step S4: fitting a binary polynomial function f m (d,h) about the parameters of the force-carrying cylinders and the weight m of the force-carrying cylinders, i.e., an optimization objective function min f m(d, h) = [d, h] T ;

[0010] Step S5: according to the allowable stress σ0 of the material of the load-bearing cylinder, a load-bearing cylinder strength constraint function f σ (d, h) < σ0 is established, and the minimum value of the objective function is found by using fmincont algorithm of Matlab, and the corresponding design variable is obtained.

[0011] As a further scheme of the present application, in step S1, specifically comprising: performing mechanical simulation on the stacked multi-satellite combination, analyzing the load-bearing cylinder parameters which have greater influence on the combination base frequency k, and finding the vector p: p = [d, h] T .

[0012] As a further scheme of the present application, in step S1: different values are selected according to the load-bearing cylinder parameters to perform mechanical simulation, and the specific process of obtaining the corresponding combination base frequency k is: different values are selected for the load-bearing cylinder outer diameter d and the load-bearing cylinder wall thickness h to perform mechanical simulation, and the corresponding combination base frequency k is obtained, and a fitting relationship matrix is established:

[0013] As a further scheme of the present application, in step S2, specifically comprising: fitting a binary polynomial function f k (d, h) about the load-bearing cylinder parameters and the combination base frequency k; f k (d, h) = p0 + p1 * d + p2 * h, wherein p0, p1, and p2 are binary polynomial constant coefficients obtained by fitting.

[0014] As a further scheme of the present application, in step S3, specifically comprising: selecting different values for the load-bearing cylinder outer diameter d and the load-bearing cylinder wall thickness h to perform 3D model design, obtaining the corresponding weight m, and establishing a fitting relationship matrix:

[0015] As a further scheme of the present application, in step S4, specifically comprising: fitting a binary polynomial function f m (d, h) about the load-bearing cylinder parameters and the load-bearing cylinder weight m; f m (d, h) = q0 + q1 * d + q2 * h; wherein q0, q1, and q2 are binary polynomial constant coefficients obtained by fitting.

[0016] As a further scheme of the present application, in step S5, according to the allowable stress σ0 of the material of the load-bearing cylinder, a load-bearing cylinder strength constraint function f σ (d, h) < σ0 is established, and the minimum value of the objective function is found by using fmincont algorithm of Matlab, and the corresponding design variable is obtained. σ (d, h) < σ0 is established.

[0017] f σ (d, h) = (fn +n*M*g) / (pi*((d / 2)^2-(d / 2-h)^2)), wherein f n is the pre-tightening force of the force-bearing cylinder when the multiple satellites are stacked; n is an overload coefficient given by the carrier rocket; M is the average weight of the stacked multiple satellite combination borne by each force-bearing cylinder; and g is the acceleration of gravity.

[0018] As a further scheme of the present application, in the step S5, the specific process of finding the minimum value of the objective function by using the fmincont algorithm of Matlab and obtaining the corresponding design variable is as follows: finding the minimum value of the objective function by using the fmincont algorithm of Matlab: min f m (d,h)=[d,h] T and obtaining the corresponding design variable: d min , h min .

[0019] The present application has the following beneficial effects:

[0020] The present application optimizes the parameters of the force-bearing cylinder of the stacked satellite, takes the outer diameter and wall thickness of the force-bearing cylinder as the design variable, takes the base frequency of the combination and the strength of the force-bearing cylinder as the constraint condition, and takes the weight of the force-bearing cylinder as the optimization target.

[0021] In order to more clearly illustrate the structural features and effects of the present application, the present application will be described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of the force-bearing cylinder structure mentioned in the present application.

[0023] Figure 2 is a schematic diagram of the stacked multiple satellite combination mentioned in the present application. DETAILED DESCRIPTION

[0024] The present application will be further described below with reference to the accompanying drawings and relevant knowledge, and will be clearly and completely described, and obviously, the described application is only a part of the embodiments of the present application, but not all the embodiments.

[0025] The parameter optimization design method of the stacked satellite force-bearing cylinder solves the problem that the designer usually considers the base frequency requirement, structural strength requirement and lightweight requirement of the combination when designing the force-bearing cylinder structure, and must sacrifice the weight of the force-bearing cylinder to improve the base frequency and structural strength of the combination, which is difficult to obtain the optimal parameters of the force-bearing cylinder.Figure 1 and Figure 2 In the formula, 1 is the wall thickness h of the bearing cylinder, 2 is the outer diameter d of the bearing cylinder, 3 is a satellite, and 4 is the bearing cylinder.

[0026] The application provides a stacked satellite bearing cylinder parameter optimization design method, which comprises the following steps:

[0027] Step S1: performing mechanical simulation on a stacked multi-satellite combination body to analyze bearing cylinder parameters affecting the fundamental frequency k of the combination body;

[0028] Step S2: performing mechanical simulation according to different values of the bearing cylinder parameters to obtain corresponding fundamental frequencies k of the combination body, and fitting a binary polynomial function f k (d, h) about the bearing cylinder parameters and the fundamental frequency k of the combination body, that is, a constraint function f k (d, h) = k0, wherein h is the wall thickness of the bearing cylinder, and d is the outer diameter of the bearing cylinder;

[0029] Step S3: selecting different values of the outer diameter d of the bearing cylinder and the wall thickness h of the bearing cylinder to perform 3D model design and obtain corresponding weights m;

[0030] Step S4: fitting a binary polynomial function f m (d, h) about the bearing cylinder parameters and the weight m of the bearing cylinder, that is, an optimization objective function min f m (d, h) = [d, h] T ;

[0031] Step S5: establishing a bearing cylinder strength constraint function f σ (d, h) < σ0 according to the allowable stress σ0 of the bearing cylinder material; and finding the minimum value of the objective function by using the fmincont algorithm of Matlab and obtaining corresponding design variables.

[0032] Further preferably, the mechanical simulation is performed on the stacked multi-satellite combination body to analyze the bearing cylinder parameters, that is, the outer diameter d of the bearing cylinder and the wall thickness h of the bearing cylinder, which have greater influences on the fundamental frequency k of the combination body, that is, the optimization problem is to find a vector p: p = [d, h] T .

[0033] Further preferably, different values of the outer diameter d of the bearing cylinder and the wall thickness h of the bearing cylinder are selected to perform mechanical simulation and obtain corresponding fundamental frequencies k of the combination body, and a fitting relationship matrix is established:

[0034]

[0035] Further preferably, according to the corresponding fundamental frequencies k of the combination body obtained above, a binary polynomial function f k (d, h) about the bearing cylinder parameters (the outer diameter d and the wall thickness h) and the fundamental frequency k of the combination body is fitted: fk (d,h) = p0 + p1 *d + p2 *h, wherein p0, p1, p2 are constant coefficients of the bivariate polynomial obtained by fitting. The base frequency constraint function is: k (d,h) = k0;

[0036] Further preferably, 3D model design is performed by selecting different values of the outer diameter d and the wall thickness h of the load-bearing cylinder, to obtain corresponding weights m, and a fitting relationship matrix is established:

[0037]

[0038] Further preferably, according to the corresponding weights m obtained above, a bivariate polynomial function f m (d,h) is fitted about the load-bearing cylinder parameters (outer diameter d, wall thickness h) and the weight m of the load-bearing cylinder: m (d,h) = q0 + q1 *d + q2 *h; wherein q0, q1, q2 are constant coefficients of the bivariate polynomial obtained by fitting;

[0039] Further preferably, a load-bearing cylinder strength constraint function f σ (d,h) is established:

[0040] f σ (d,h) = (f n +n*M*g) / (π*((d / 2)^2-(d / 2-h)^2)), wherein f n is the pre-tightening force borne by the load-bearing cylinder when the multi-satellite stack is stacked; n is an overload coefficient given by the launch vehicle; M is the average weight of the stacked multi-satellite assembly borne by each load-bearing cylinder; and g is the acceleration of gravity.

[0041] In addition, a load-bearing cylinder strength constraint function is established according to the allowable stress σ0 of the load-bearing cylinder material, and the strength constraint function is: σ (d,h) < σ 0。

[0042] Further preferably, the fmincont algorithm of Matlab is used to find the minimum value of the objective function: min f m (d,h) = [d,h] T , and the corresponding design variables d min , h min are obtained.

[0043] The technical principles of the present application are described above in combination with specific embodiments, which are only preferred embodiments of the present application. The protection scope of the present application is not limited to the above-described embodiments only, and any technical solutions falling within the concept of the present application shall fall within the protection scope of the present application. Other specific embodiments of the present application can be conceived by those skilled in the art without creative efforts, and these embodiments shall fall within the protection scope of the present application.

Claims

1. A method for parameter optimization design of a stack satellite's load-carrying cylinder, characterized in that, Comprising the following steps: Step S1: Perform mechanical simulation on the stacked multi-satellite combination, analyze the load-bearing cylinder parameters that affect the fundamental frequency k of the combination, and form a vector p; p=[d, h], wherein h is the wall thickness of the load-bearing cylinder, and d is the outer diameter of the load-bearing cylinder; Step S2: According to the different values of the force cylinder parameters, the mechanical simulation is carried out to obtain the corresponding combination body fundamental frequency k, and the binary polynomial function f about the force cylinder parameters and the combination body fundamental frequency k is fitted k (d,h), that is, the constraint function is: f k (d,h)=k0; f k (d,h)=p0+p1*d+p2*h, wherein p0, p1 and p2 are the binary polynomial constant coefficients obtained by fitting Step S3: Select different values for the outer diameter d of the load-bearing cylinder and the wall thickness h of the load-bearing cylinder to perform 3D model design, and obtain the corresponding weight m; Step S4: fitting a bivariate polynomial function f of the parameters of the load cylinder and the weight m of the load cylinder m (d,h), i.e. the optimization objective function: min f m (d,h); Step S5: According to the allowable stress σ0 of the load-carrying cylinder material, a load-carrying cylinder strength constraint function f is established σ (d, h) < σ0; and the minimum value of the objective function is found by using fmincont algorithm of Matlab, and the corresponding design variable is obtained; wherein, f σ (d, h) = (f n + n * M * g) / (π * ((d / 2)^2 - (d / 2 - h)^2)), wherein, f n is the pre-tightening force of the load-carrying cylinder when the multiple satellites are stacked; n is an overload coefficient given by the carrier rocket; M is the average weight of the stacked multiple satellite combination borne by each load-carrying cylinder; and g is the acceleration of gravity.

2. The method of claim 1, wherein, In step S1, different values are selected according to the parameters of the load-bearing cylinder to perform mechanical simulation, and the specific process of obtaining the corresponding base frequency k of the combination is as follows: different values are selected for the outer diameter d of the load-bearing cylinder and the wall thickness h of the load-bearing cylinder to perform mechanical simulation, and the corresponding base frequency k of the combination is obtained, and a fitting relationship matrix is established: .

3. The method of claim 2, wherein, The step S3 specifically includes selecting different values for the outer diameter d of the load-bearing cylinder and the wall thickness h of the load-bearing cylinder to perform 3D model design, obtaining a corresponding weight m, and establishing a fitting relationship matrix: .

4. The method for optimizing the parameters of a stacked satellite load-bearing cylinder as described in claim 3, characterized in that, The step S4 specifically comprises fitting a binary polynomial function f m (d,h) ; f m (d,h) = q0 + q1 *d + q2 *h; wherein q0, q1, q2 are binary polynomial constant coefficients obtained by fitting.

5. The method of claim 4, wherein, In the step S5, the minimum value of the objective function is found by using the fmincon algorithm of Matlab, and the specific process of obtaining the corresponding design variable is as follows: the minimum value of the objective function is found by using the fmincon algorithm of Matlab: min f m (d, h), and the corresponding design variable d min , h min is obtained.

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