Single material structure thermal deformation optimization design method with directivity constraint

Abstract

The application provides a single material structure thermal deformation optimization design method with directivity constraint, which comprises the following steps: firstly, an initial three-dimensional parameterized model of a star sensor support is established according to the design requirements of the star sensor support; then, the installation point positions of the star sensor support on the equipment cabin plate are taken as design variables, the absolute value of the directivity deflection angle of the star sensor installation surface in a set temperature range is taken as an objective function, the installation surface position of the star sensor remains unchanged, the connection relationship between the installation points remains unchanged, the global strain energy is less than a set value, and the fundamental frequency is greater than a set value are taken as constraint conditions, and an optimization model is established; and finally, the final optimization result is obtained by solving the optimization model. The application starts from the installation point positions of the star sensor support on the equipment cabin plate, optimizes the installation point positions, realizes mutual offset of the structure thermal deformation in certain specific directions by adopting symmetrization design, and thus the control difficulty of the directivity angle of the star sensor installation surface in the variable temperature environment is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of star sensor support structure design, in particular to a single material structure thermal deformation optimization design method with directivity constraint, which is used for the directivity shape optimization design of a star sensor support. BACKGROUND

[0002] With the development of space technology, the requirement for the pointing accuracy of a star sensor on a satellite is getting higher and higher. The star sensor support is a device for installing a star sensor on a satellite equipment cabin panel at a specific angle, and the pointing accuracy of the star sensor installation surface directly affects the measurement accuracy of the star sensor.

[0003] The space where the satellite is located has a high-low temperature alternating environment. However, due to the thermal expansion and contraction of the material, the unbalanced thermal deformation of the star sensor support in the complex variable temperature environment in space will seriously affect the pointing accuracy of the star sensor installation surface. Therefore, in order to reduce the influence of the thermal deformation of the star sensor support on the measurement accuracy of the star sensor, the thermal deformation of the star sensor support is currently controlled in the following two ways: one is to design the star sensor support by using a material with a low thermal expansion coefficient, such as invar, but this kind of material often has a large density, resulting in a redundant structure weight, which is not conducive to the lightweight of the space product; the other is to design by matching two materials with different thermal expansion coefficients, and the deformation of the materials with different thermal expansion coefficients is coordinated to finally realize the overall thermal deformation regulation and control of the star sensor support, but this design method needs to consider the connection design of the two materials, which increases the design complexity and preparation difficulty. SUMMARY

[0004] In order to reduce the influence of the thermal deformation of the star sensor support on the measurement accuracy of the star sensor, and overcome the problems existing in the prior art, the present application takes a different approach, and does not improve the design of the material of the star sensor support, but allows the star sensor support structure to have thermal deformation. Starting from the installation point position of the star sensor support on the equipment cabin panel, the installation point position is optimized and designed, the thermal deformation of the star sensor support structure in certain specific directions is offset by symmetrization design, so as to reduce the control difficulty of the pointing angle of the star sensor installation surface in the variable temperature environment.

[0005] The technical scheme of the present application is as follows:

[0006] The single material structure thermal deformation optimization design method with directivity constraint comprises the following steps:

[0007] Step 1: according to the design requirements of the star sensor support, an initial three-dimensional parametric model of the star sensor support is established; wherein from the mounting points of the star sensor support on the equipment cabin plate to the star sensor mounting surface in the star sensor support, a plurality of connecting rods are connected to form a three-dimensional parametric model of the star sensor support; and the overall layout of all mounting points of the star sensor support on the equipment cabin plate adopts a symmetrical layout;

[0008] Step 2: build an optimization model:

[0009] Take the mounting point position of the star sensor support on the equipment cabin plate as the design variable, take the minimum absolute value of the pointing angle of the star sensor mounting surface in the star sensor support within the set temperature range as the objective function, take the unchanged position of the star sensor mounting surface, the unchanged connection relationship between the star sensor mounting surface and the mounting points of the star sensor support on the equipment cabin plate, the global strain energy of the star sensor support less than the set value, and the fundamental frequency of the star sensor support greater than the set value as the constraint conditions, and establish the optimization model;

[0010] The pointing angle refers to the pointing deviation of the star sensor mounting surface caused by the maximum allowable temperature difference leading to the deformation of the star sensor support, and the value is calculated by extracting the mounting hole coordinates of the star sensor mounting surface through the finite element software;

[0011] The global strain energy refers to the global strain energy generated by the deformation of the star sensor support after a concentrated force load perpendicular to the star sensor mounting surface is applied at the overall geometric center position of the star sensor mounting surface, and is directly solved by the finite element software;

[0012] The fundamental frequency refers to the first order mode of the star sensor support after modal analysis of the star sensor support, and is directly solved by the finite element software;

[0013] Step 3: the optimization algorithm is used to iteratively calculate the optimization model established in step 2 to obtain the design variable that satisfies the optimization constraint condition and has the optimal objective function; wherein in each iteration process, the pointing angle of the star sensor mounting surface corresponding to the previous design variable, and the global strain energy and the fundamental frequency of the star sensor support are obtained by finite element simulation calculation.

[0014] Further, in step 1, when the number of mounting points of the star sensor support on the equipment cabin plate is odd, then there are odd number of mounting points on the symmetry plane, and the remaining mounting points are symmetrically arranged on the left and right of the symmetry plane; when the number of mounting points of the star sensor support on the equipment cabin plate is even, then there is no mounting point on the symmetry plane or there are even number of mounting points on the symmetry plane, and the remaining mounting points are symmetrically arranged on the left and right of the symmetry plane.

[0015] Further, the mounting points of the star sensor support on the equipment cabin plate are five, the positions of which are on the same circle, and the center of the circle is symmetric with the line connecting the center of the circle and a mounting point, the other four mounting points are symmetric with respect to the symmetric axis.

[0016] The mounting point on the symmetric axis is the first mounting point, the central angle between the first mounting point and the adjacent mounting point is θ1, the central angle between the first mounting point and the interval mounting point is θ2, the diameter of the circle is D, and the vertical distance h between the overall geometric center of the star sensor mounting surface and the equipment mounting surface of the star sensor support is obtained.

[0017] (θ1, θ2, D, h) are used as design variables for representing the positions of the mounting points of the star sensor support on the equipment cabin plate, and in the optimization process, the constraint conditions that the five mounting points are on the same circle and the two groups of mounting points are symmetric with respect to the symmetric axis are maintained.

[0018] Further, the mounting points of the star sensor support on the equipment cabin plate are five, wherein four mounting points are divided into two groups, and the two groups of mounting points are symmetric with respect to a certain straight line between the two groups of mounting points, and the fifth mounting point is on the symmetric axis; a rectangular coordinate system is constructed, a point on the symmetric axis is taken as the origin, the symmetric axis is taken as the Y axis, the coordinates x1, y1, x2, y2 of the two mounting points on one side of the symmetric axis, the Y axis coordinate y3 of the fifth mounting point, and the vertical distance h between the overall geometric center of the star sensor mounting surface and the equipment mounting surface of the star sensor support form a design variable sequence (x1, y1, x2, y2, y3, h); and in the optimization process, the constraint conditions that the two groups of mounting points are symmetric with respect to a certain straight line between the two groups of mounting points, and the fifth mounting point is on the symmetric axis are maintained.

[0019] Advantages

[0020] The present application reduces the influence of the thermal deformation of the star sensor support on the measurement accuracy of the star sensor, optimizes the positions of the mounting points of the star sensor support on the equipment cabin plate, reduces the directional deformation caused by the thermal deformation of the star sensor support structure itself, and thus reduces the influence of the thermal deformation of the star sensor support on the measurement accuracy of the star sensor.

[0021] The application abandons the thought of restraining the thermal deformation of the material in the traditional scheme, and instead grasps the key factor of the measurement accuracy of the star sensor: the directivity of the mounting surface of the star sensor; in the scheme of the application, under the condition of allowing the thermal deformation of the star sensor support structure, through the optimization design of the mounting point position, when the star sensor support structure is deformed by heat, the thermal deformation of the star sensor support structure in certain specific directions is offset, so as to reduce the directivity deformation of the star sensor support structure, so as to meet the specific directivity requirements, thereby reducing the influence of the thermal deformation of the star sensor support on the measurement accuracy of the star sensor. Moreover, the star sensor support can realize the technical scheme of the application by using a single material, and the method has universality for different materials.

[0022] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and / or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and / or additional aspects and advantages of the application will become apparent and be readily understood by considering the following detailed description, from which the singular aspects become apparent.

[0024] Figure 1 The flowchart of the star sensor support directivity shape optimization design method of the application.

[0025] Figure 2 The initial structure diagram of the star sensor support in embodiment 1 of the application.

[0026] Figure 3 The parameterized design diagram of the mounting point of the star sensor support on the equipment cabin plate in embodiment 1 of the application.

[0027] Figure 4 The optimized structure diagram of the star sensor support in embodiment 1 of the application.

[0028] Figure 5 The initial structure diagram of the star sensor support in embodiment 2 of the application.

[0029] Figure 6 The parameterized design diagram of the mounting point of the star sensor support on the equipment cabin plate in embodiment 2 of the application.

[0030] Figure 7 The optimized structure diagram of the star sensor support in embodiment 2 of the application. DETAILED DESCRIPTION

[0031] For the star sensor support, due to the installation requirements of the star sensor device, the relative positions of the mounting blocks for connecting with the star sensor in the star sensor support are unchangeable, and the normal direction of the fitting surface in the mounting blocks matched with the star sensor is the key factor affecting the pointing accuracy of the star sensor. In order to reduce the influence of the thermal deformation of the star sensor support on the measurement accuracy of the star sensor, the installation point position of the star sensor support on the equipment cabin plate is optimized, and the pointing deformation caused by the thermal deformation of the star sensor support structure (i.e. the offset of the normal direction of the star sensor mounting surface) is reduced in the case that the thermal deformation of the star sensor support structure occurs, so that the influence of the thermal deformation of the star sensor support on the measurement accuracy of the star sensor is reduced.

[0032] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0034] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0035] Embodiment 1:

[0036] In this embodiment, the installation points of the star sensor support on the equipment cabin plate are a total of 5 points, as shown in Figure 2 The star sensor support has symmetry, and the 5 installation points between the star sensor support and the equipment cabin plate are distributed in a circular shape, are located on the same circumference, and the center of the circumference and the line connecting a certain installation point are the symmetry axis, and the other four installation points are divided into two groups, and the two groups of installation points are symmetric about the symmetry axis.

[0037] As shown in Figure 3 The coordinates of the five mounting points are controlled by four parameters: the first mounting point is on the symmetry axis, the central angle between the first mounting point and the adjacent mounting point is θ1, the central angle between the first mounting point and the interval mounting point is θ2, the circumference diameter is D, and h is the vertical distance from the overall geometric center of the star sensor mounting surface to the mounting surface of the star sensor support device. Due to the symmetry of the star sensor support structure, θ1 can determine the positions of the two mounting points B2 and B4, and θ2 can determine the positions of the two mounting points B1 and B5. Thus, (θ1, θ2, D, h) are used as design variables to represent the positions of the mounting points of the star sensor support on the equipment cabin plate.

[0038] The specific steps are as follows:

[0039] Step 1: According to the design requirements of the star sensor support, an initial three-dimensional parametric model of the star sensor support is established in the finite element software. The star sensor mounting surface in the star sensor support is connected to the mounting points of the star sensor support on the equipment cabin plate through a plurality of connecting rods to form a three-dimensional parametric model of the star sensor support.

[0040] Step 2: Construct an optimization model:

[0041] The above (θ1, θ2, D, h) are used as design variables, and the absolute value of the pointing angle of the star sensor mounting surface in the star sensor support within a set temperature range is used as the objective function, which is the minimum. The pointing angle is the pointing deviation of the star sensor mounting surface caused by the maximum allowed temperature difference leading to the deformation of the star sensor support. Its value is calculated by extracting the coordinates of the four mounting holes of the star sensor mounting surface through the finite element software and using Matlab code.

[0042] The position of the star sensor mounting surface remains unchanged, the connection relationship between the star sensor mounting surface and the mounting points of the star sensor support on the equipment cabin plate remains unchanged, the global strain energy of the star sensor support is less than a set value, and the fundamental frequency of the star sensor support is greater than a set value as the constraint conditions.

[0043] The global strain energy refers to the global strain energy generated by the deformation of the star sensor support after a concentrated force load perpendicular to the star sensor mounting surface is applied at the overall geometric center position of the four mounting holes of the star sensor mounting surface, which is directly solved by the finite element software.

[0044] The fundamental frequency refers to the first-order mode of the star sensor support after modal analysis of the star sensor support, which is directly solved by the finite element software.

[0045] In the optimization process, the five mounting points are kept on the same circumference, and the two groups of mounting points are left-right symmetrical relative to the symmetry axis, thereby establishing an optimization model:

[0046] find: x = (θ1, θ2, D, h)

[0047] min: α(x) = |β(x) - β0|

[0048] s.t.: E(x) < E0

[0049] f(x) > f0

[0050] where x is the design variable, including θ1, θ2, D, h; α(x) is the pointing angle of the star sensor mounting surface, β0 is the pointing angle of the star sensor mounting surface before deformation of the star sensor support, β(x) represents the pointing angle of the star sensor mounting surface after deformation of the star sensor support under the maximum allowable temperature difference under the parameter x; E(x) is the global strain energy of the star sensor support, which is used to measure the stiffness of the star sensor support, E0 is the upper limit thereof, and the value is 0.05 mJ; f(x) is the fundamental frequency of the star sensor support, and f0 is the lower limit thereof, and the value is 600 Hz; the stiffness and the fundamental frequency of the star sensor support are taken as the constraint functions of the optimization model, so as to ensure the anti-deformation performance of the star sensor support.

[0051] Step 3: The optimization model established in step 2 is iteratively calculated by using the GCMMA optimization algorithm to obtain the design variable meeting the requirement of the objective function; wherein in each iteration process, the pointing angle of the star sensor mounting surface corresponding to the previous design variable, and the global strain energy and the fundamental frequency of the star sensor support are obtained by finite element simulation calculation.

[0052] The finally obtained star sensor support model is as shown in Figure 4 , and the comparison of the design variable, the objective function and the constraint function before and after optimization is shown in Table 1.

[0053] Table 1

[0054] Example 1 [theta]1 / ° [theta]2 / ° D / mm h / mm α / ° E / mJ f / Hz Before optimization 50.00 120.00 160.00 105.00 1.2 x 10 -2 ]]> 0.0400 814.90 After optimization 46.18 114.44 153.10 103.29 3.4 x 10 -5 ]]> 0.0425 841.47

[0055] Example 2:

[0056] In this embodiment, the mounting points of the star sensor support on the equipment cabin plate are a total of 5 points, as shown in Figure 5As shown, the star sensor support has symmetry, four of the five mounting points between the equipment cabin plate are divided into two groups, and the two groups of mounting points are symmetric about a certain line between the two groups of mounting points, and the fifth mounting point is on the symmetry axis; a rectangular coordinate system is constructed, a point on the symmetry axis is taken as the origin, the symmetry axis is the Y axis, the coordinates x1, y1, x2, y2 of the two mounting points on one side of the symmetry axis, the y-axis coordinate y3 of the fifth mounting point, and the vertical distance h from the overall geometric center of the star sensor mounting surface to the equipment mounting surface of the star sensor support are taken as design variables (x1, y1, x2, y2, y3, h) representing the mounting point positions of the star sensor support on the equipment cabin plate.

[0057] The specific steps are:

[0058] Step 1: According to the design requirements of the star sensor support, an initial three-dimensional parametric model of the star sensor support is established in the finite element software; wherein a plurality of connecting rods are used to connect between the mounting points of the star sensor support on the equipment cabin plate and the star sensor mounting surface in the star sensor support, to form a three-dimensional parametric model of the star sensor support;

[0059] Step 2: Construct the optimization model:

[0060] The above (x1, y1, x2, y2, y3, h) are taken as design variables, and the minimum absolute value of the pointing angle of the star sensor mounting surface in the star sensor support within a set temperature range is taken as the objective function. The pointing angle is the pointing deviation of the star sensor mounting surface caused by the deformation of the star sensor support due to the maximum allowed temperature difference, which is calculated by extracting the coordinates of the four mounting holes of the star sensor mounting surface through the finite element software and using Matlab code.

[0061] The position of the star sensor mounting surface remains unchanged, the connection relationship between the star sensor mounting surface and the mounting points of the star sensor support on the equipment cabin plate remains unchanged, the global strain energy of the star sensor support is less than a set value, and the fundamental frequency of the star sensor support is greater than a set value.

[0062] The global strain energy refers to the global strain energy generated by the deformation of the star sensor support after a concentrated force load perpendicular to the star sensor mounting surface is applied at the overall geometric center position of the four mounting holes of the star sensor mounting surface, which is directly solved by the finite element software.

[0063] The fundamental frequency refers to the first-order mode of the star sensor support after modal analysis of the star sensor support, which is directly solved by the finite element software.

[0064] And in the optimization process, the two groups of mounting points are symmetric about a certain line between the two groups of mounting points, and the fifth mounting point is on the symmetry axis, thereby establishing an optimization model:

[0065] find: x = (x1, y1, x2, y2, y3, h)

[0066] min: a(x) = |b(x) - b0|

[0067] s.t.: E(x) < E0

[0068] f(x) > f0

[0069] Where x is the design variable, including x1, y1, x2, y2, y3, h; a(x) is the pointing angle of the star sensor support, b0 is the pointing angle of the star sensor mounting surface before the deformation of the star sensor support, b(x) represents the pointing angle of the star sensor mounting surface after the deformation of the star sensor support under the maximum allowable temperature difference under the parameter x; E(x) is the global strain energy of the star sensor support, which is used to measure the stiffness of the star sensor support, E0 is the upper limit, and the value is 0.05mJ; f(x) is the fundamental frequency of the star sensor support, and f0 is the lower limit, and the value is 600Hz; The stiffness and the fundamental frequency of the star sensor support are used as the constraint function of the optimization model to ensure the anti-deformation performance of the star sensor support.

[0070] Step 3: The optimization model established in step 2 is iteratively calculated by using the GCMMA optimization algorithm to obtain the design variable meeting the requirements of the objective function; Wherein in each iteration process, the pointing angle of the star sensor mounting surface corresponding to the previous design variable, and the global strain energy and the fundamental frequency of the star sensor support are obtained by finite element simulation calculation.

[0071] The finally obtained star sensor support model is as Figure 7 , and the comparison of the design variables, the objective function and the constraint function before and after optimization is shown in Table 2.

[0072] Example 2 [ x1 / mm ] [y1 / mm] [ x2 / mm ] [y2 / mm] [y3 / mm] h / mm α / ° E / mJ f / Hz Before optimization 50.00 50.00 50.00 -50.00 0.00 100.00 5.6 x 10 -2 ]] 0.0219 1016.50 After optimization 159.63 63.67 56.78 -38.91 -7.09 93.78 8.8 x 10 -5 ]] 0.0427 1042.60

[0073] Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and modifications to the above-mentioned embodiments without departing from the principles and purposes of the present application within the scope of the present application.

Claims

1. A method for single material structure thermal distortion optimization with directional constraints, characterized in that: The method comprises the following steps: Step 1: according to the design requirements of the star sensor support, an initial three-dimensional parametric model of the star sensor support is established; Wherein from the mounting point of the star sensor support on the equipment cabin plate to the star sensor mounting surface in the star sensor support, a plurality of connecting rods are connected to form a three-dimensional parametric model of the star sensor support; and the overall layout of all mounting points of the star sensor support on the equipment cabin plate adopts a symmetrical layout; The mounting point of the star sensor support on the equipment cabin plate is five, which is located on the same circumference, and the center of the circle and a certain mounting point are connected as the symmetry axis, and the remaining four mounting points are divided into a group, and the two groups of mounting points are symmetrically arranged on the left and right of the symmetry axis; Taking the mounting point on the symmetry axis as the first mounting point, the central angle of the first mounting point and the adjacent mounting point is θ1, the central angle of the first mounting point and the interval mounting point is θ2, the diameter of the circle is D, and the vertical distance h from the overall geometric center of the star sensor mounting surface to the equipment mounting surface of the star sensor support is obtained; Step 2: construct an optimization model: Taking the mounting point position of the star sensor support on the equipment cabin plate as the design variable, taking the minimum absolute value of the pointing deviation of the star sensor mounting surface in the star sensor support within the set temperature range as the objective function, taking the star sensor mounting surface position unchanged, the connection relationship between the star sensor mounting surface and the mounting point of the star sensor support on the equipment cabin plate unchanged, the global strain energy of the star sensor support less than the set value, and the fundamental frequency of the star sensor support greater than the set value as the constraint condition, an optimization model is established; Wherein (θ1, θ2, D, h) is used as the design variable representing the mounting point position of the star sensor support on the equipment cabin plate, and in the optimization process, the constraint conditions that the five mounting points are located on the same circumference and the two groups of mounting points are symmetrically arranged on the left and right of the symmetry axis are maintained; Step 3: the optimization algorithm is used to iteratively calculate the optimization model established in step 2 to obtain the design variable that satisfies the optimization constraint condition and has the optimal objective function; Wherein in each iteration process, the pointing deviation of the star sensor mounting surface corresponding to the previous design variable, and the global strain energy and the fundamental frequency of the star sensor support are obtained by finite element simulation calculation.

2. The method of claim 1, wherein: The mounting point of the star sensor support on the equipment cabin plate is five, wherein four mounting points are divided into a group, and the two groups of mounting points are symmetrically arranged on the left and right of a certain straight line between the two groups of mounting points, and the fifth mounting point is on the symmetry axis; a rectangular coordinate system is constructed, a point on the symmetry axis is taken as the origin, the symmetry axis is taken as the Y axis, the coordinates x1, y1, x2, y2 of the two mounting points on one side of the symmetry axis, the y axis coordinate y3 of the fifth mounting point, and the vertical distance h from the overall geometric center of the star sensor mounting surface to the equipment mounting surface of the star sensor support form a design variable sequence (x1, y1, x2, y2, y3, h); and in the optimization process, the constraint conditions that the two groups of mounting points are symmetrically arranged on the left and right of a certain straight line between the two groups of mounting points, and the fifth mounting point is on the symmetry axis are maintained.

3. The method of claim 1, wherein: The pointing deviation refers to the pointing deviation of the star sensor mounting surface caused by the maximum allowable temperature difference leading to the deformation of the star sensor support.

4. The method of claim 1, wherein: The global strain energy refers to global strain energy generated by deformation of the star sensor support after a concentrated force load perpendicular to the star sensor mounting surface is applied at the position of the overall geometric center of several mounting holes of the star sensor mounting surface.

5. The method of claim 1, wherein: The fundamental frequency refers to a first-order mode of the star sensor support after modal analysis is performed on the star sensor support.

6. A computer device, comprising: The method comprises: at least one processor; and a memory storing computer instructions executable on the processor, the instructions being executed by the processor to implement the steps of the method of any one of claims 1-5.

7. A computer-readable storage medium storing a computer program, wherein the computer program comprises the following steps of: receiving a request for a resource from a client; determining whether the client is authorized to access the resource; and if the client is authorized to access the resource, providing the resource to the client. The computer program, when executed by the processor, implements the steps of the method of any one of claims 1-5.

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