Ground equivalent test piece design method for simulating quality characteristics of miniature spacecraft

Abstract

The invention discloses a ground equivalent test piece design method for simulating the quality characteristic of a micro spacecraft, which is used for simulating and researching the disturbance condition of the micro spacecraft under the microgravity condition in a tower falling experiment, and the structure design is mainly used for the three-dimensional model design and the quality characteristic parameter calculation function of Solidworks software. An axial centroid symmetric inertia parameter adjusting method is mainly adopted; the overall structure design method comprises the following steps: preliminarily determining a frame main load-bearing structure under the condition of meeting the requirements required by the experiment according to known parameters obtained from a real spacecraft, and then adjusting and simulating the mass center, the rotational inertia, the inertia product and the overall mass of a ground equivalent test piece by using a mass block; the error between the parameters and actual spacecraft parameters is less than or equal to 3%; according to the design method of the ground equivalent test piece, on the premise that the spacecraft is not affected, the real quality characteristic is accurately simulated with low cost and a simple structure, and the design method has a good reference effect on ground tests of miniature spacecrafts and ground tests of complex equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of ground test of micro-spacecraft, and in particular relates to a design method of a ground equivalent test piece for simulating the mass characteristics of a micro-spacecraft. Background Art

[0002] With the rapid development of materials science, microelectronics technology, precision manufacturing technology, etc., it has become possible to manufacture smaller, lighter and more powerful spacecraft. Compared with traditional large spacecraft, the R&D and launch costs of micro spacecraft are lower, which enables more countries and institutions to participate in space activities. Micro spacecraft has gradually become one of the main directions of spacecraft research. However, due to the complexity and precision of micro spacecraft, it is difficult to conduct ground tests directly. Many spacecraft use equivalent test pieces with corresponding mass characteristics to conduct ground tests. In terms of the launch disturbance of spacecraft carrying payloads, it is particularly important to establish accurate, economical and practical ground equivalent test pieces for ground equivalent tests and to know the disturbance of micro spacecraft in microgravity in advance. Studying the attitude disturbance after the launch of payloads in advance through ground tests can not only reduce costs and avoid unnecessary losses to a large extent, but also verify the technology.

[0003] At present, patent CN202211281718.3 discloses an "adjustable moment of inertia simulation device", which changes the moment of inertia parameters by changing the distance of the counterweight block relative to the rotating axis. The application field of this device is limited. The disadvantage is that the adjustment range is limited and it can only be adjusted in a two-dimensional plane, and it cannot effectively simulate the inertia parameters of three-dimensional space.

[0004] In the article "Research on Space Vehicle Simulation Test Bench", Chen Tengfei designed several configurations of mass inertia simulation mechanisms based on mass characteristic indicators, selected a suitable configuration through programming, and installed the configuration on the axial slide bar to complete the simulation of the test piece's moment of inertia. Although the simulated test piece designed by this method can simulate and adjust the moment of inertia in three-dimensional space, it cannot adjust the product of inertia, and the use of the simulated test piece is greatly restricted by the environment, and the simulation device cannot move effectively and withstand impact. Summary of the invention

[0005] The present invention proposes a design method for a micro-spacecraft equivalent test piece with a simple structure, high precision and strong practicality, which can effectively simulate the mass characteristic parameters of the micro-spacecraft. While satisfying the requirement of simulating accurate mass characteristics, this method is also relatively simple in structure, low in cost and easy to process.

[0006] The technical solution to realize the present invention is: a method for designing a ground equivalent test piece simulating the mass characteristics of a micro-spacecraft, the steps are as follows:

[0007] Step 1: The experimental objects include two sets of separation mechanisms and two loads. The physical assemblies of the two sets of separation mechanisms and the two loads and their dimensional parameters are obtained, and the actual mass characteristic parameters of the micro-spacecraft are obtained at the same time. It is assumed that the error of the ground equivalent test piece is ≤3%, the X-axis is the load launch direction, the Y-axis is parallel to the short side of the top frame, +Z is determined by +X and +Y by the right-hand rule, and the coordinate system of the ground equivalent test piece is consistent with the actual spacecraft.

[0008] Step 2: According to the dimensional parameters of the two separation mechanisms and the two load assemblies and the actual mass characteristic parameters of the micro-spacecraft, the ground equivalent test piece is determined to be a cube structure and has length, width and height dimensions. The actual mass characteristic parameters of the micro-spacecraft include mass, center of mass coordinates, moment of inertia and product of inertia. The cube structure is convenient for installing mass blocks to adjust the mass, center of mass, moment of inertia and product of inertia. The frame main load-bearing structure of the ground equivalent test piece is designed according to the experimental requirements.

[0009] The main load-bearing structure of the frame of the ground equivalent test piece includes: a top frame, a bottom frame, an upper mass block connecting plate, a lower mass block connecting plate, an electromagnet, an electric controller, an electric controller mounting plate, a baffle, a central mass compensation structure, two separation mechanism mounting plates, two symmetrically arranged front and rear lateral frames, two symmetrically arranged left and right lateral frames, and four columns.

[0010] Step 3: Assemble the load and separation mechanism in the main load-bearing structure of the frame of the ground equivalent test piece, and then adjust the center of mass of the frame of the ground equivalent test piece by adding the first adjustment mass block and the second adjustment mass block to the main load-bearing structure of the frame of the ground equivalent test piece, and calculate the masses of the first adjustment mass block and the second adjustment mass block, so that the center of mass coordinates of the frame of the ground equivalent test piece meet the error requirement of ≤3%.

[0011] Step 4: Based on the main load-bearing structure of the frame of the ground equivalent test piece in step 3, two symmetrical first mass blocks, second mass blocks, third mass blocks, fourth mass blocks, fifth mass blocks, and sixth mass blocks are loaded on the outer surfaces in the diagonal directions of the X-axis, Y-axis, Z-axis, XY plane, YZ plane, and ZX plane, respectively. According to the known actual spacecraft moment of inertia and product of inertia parameters, an inertia parameter adjustment method symmetrical along the axial center of mass is adopted. The inertia parameters include the moment of inertia and product of inertia. The mass of the corresponding mass blocks is solved so that the moment of inertia and product of inertia of the ground equivalent test piece at this time are within an error range of ≤3%.

[0012] Step 5: Determine whether the total mass of the ground equivalent test piece after adding the above-mentioned mass block meets the requirement of ≤3%. If so, complete the design; otherwise, add a mass block to the center mass compensation structure until the requirement of ≤3% is met.

[0013] Compared with the prior art, the present invention has the following significant advantages:

[0014] (1) The present invention has the function of simulating and adjusting the mass characteristics of three-dimensional space (including mass, center of mass, moment of inertia, and product of inertia).

[0015] (2) The simulation device of the present invention can also be used for secondary use. According to the test requirements, various parameters of the quality characteristics of the equivalent test piece can be adjusted within a certain limit, and the simulation quality characteristic parameters are of high accuracy.

[0016] (3) The present invention has a simple structure, high precision, low cost and strong practicality. It can be used in high-precision or complex equipment fields where ground experiments cannot be conducted to achieve the goals of accuracy, high efficiency and low cost.

[0017] (4) The overall ground test device is divided into multiple components, and the components can be replaced according to different test components. Since the present invention is an independent test device, accurate results can be obtained without affecting the aircraft at all. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram for reference of the overall structure of a mass equivalent test piece simulating a micro-spacecraft.

[0019] Figure 2 Assembly drawings for load and separation mechanisms.

[0020] Figure 3 This is the main load-bearing structure diagram of the ground equivalent test piece frame.

[0021] Figure 4 Map of the mass positions used to adjust the inertia parameters of the ground equivalent test piece. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0024] In addition, in the present invention, the descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0025] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation" and the like should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; "connection" can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] The following will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention in combination with this design example.

[0028] Combination Figure 1 to Figure 4 , a ground equivalent test piece design method for simulating the mass characteristics of a micro-spacecraft, the steps are as follows:

[0029] Step 1: If Figure 2 As shown, the experimental object includes two sets of separation mechanisms 20 and two loads 21. The physical assembly of the two sets of separation mechanisms 20 and the two loads 21 and their size parameters are obtained, and the actual mass characteristic parameters of the micro spacecraft are obtained at the same time. It is assumed that the error of the ground equivalent test piece is ≤3%, the X-axis is the load launch direction, the Y-axis is parallel to the short side direction of the top frame 1, +Z is determined by +X and +Y by the right-hand rule, and the coordinate system of the ground equivalent test piece is consistent with the actual spacecraft, wherein the mass characteristic parameters include mass, center of mass coordinates, moment of inertia and product of inertia.

[0030] Furthermore, after the separation structure 20 and the load 21 are assembled, the necessary parameters for designing the ground equivalent test piece are measured, including the height h1, the maximum diameter d1, and the two load installation distances l1. h1 is used to determine the frame height range, d1 is used to design the separation mechanism mounting plate 19 that carries the assembly, and l1 is used to determine the frame width.

[0031] The mass characteristic parameters of the real spacecraft are known:

[0032] Mass: m0, unit: kg;

[0033] Center of mass coordinates: (x0, y0, z0), unit: mm;

[0034] Inertia parameters: Unit: kg / mm 2 .

[0035] Step 2: Determine that the ground equivalent test piece is a cube structure and has length, width and height dimensions according to the dimensional parameters of the two separation mechanisms 20 and the two loads 21 assemblies and the actual mass characteristic parameters of the micro-spacecraft. The actual mass characteristic parameters of the micro-spacecraft include mass, center of mass coordinates, moment of inertia and product of inertia. The cube structure facilitates the installation of mass blocks to adjust the mass, center of mass, moment of inertia and product of inertia. Design the main load-bearing structure of the frame of the ground equivalent test piece according to the experimental requirements.

[0036] Furthermore, the basic dimensions of the cubic test piece frame are length l2, width w2, and height h2, where: w2>l1+d1, h1<h2

[0037] like Figure 3 As shown, the main load-bearing structure of the frame of the ground equivalent test piece includes: a top frame 1, a bottom frame 2, an upper mass block connecting plate 5, a lower mass block connecting plate 6, an electromagnet 15, an electric controller 16, an electric controller mounting plate 17, a baffle 18, a central mass compensation structure 22, two separation mechanism mounting plates 19, two symmetrically arranged front and rear lateral frames 3, two symmetrically arranged left and right lateral frames 4, and four columns 23. The four columns 23 are made of angle steel as support, and the top frame 1, the bottom frame 2, the front and rear lateral frames 3 and the left and right lateral frames 4 are connected to the top and bottom, front and back, and left and right of the four columns 23, respectively. The upper mass block connecting plate 5 is fixed on the top frame 1, the lower mass block connecting plate 6 is fixed on the bottom frame 2, the baffle 18 is fixed on the lower mass block connecting plate 6, the electric controller mounting plate 17, the central mass compensation structure 22, and the two separation mechanism mounting plates 19 are all fixed between the two front and rear lateral frames 3, and the two separation mechanism mounting plates 19 are parallel to the top frame 1, the electric controller 16 and the central mass compensation structure 22 are both fixed on the electric controller mounting plate 17, the electromagnet 15 is fixed on the upper mass block connecting plate 5 and is located on the X-axis, and all components are connected with screws and threads.

[0038] Installation process and component functions of the main frame bearing structure:

[0039] ​Step 1: Install the Y-axis lateral frame 3 and the Z-axis lateral frame 4 around the top frame 1 and the bottom frame 2 as the basic frame structure, and the outer surface of the lateral frame can be used to install the mass block;

[0040] Step 2: The columns 23 are installed at the four lateral corners of the main load-bearing mechanism of the frame to fix and support the overall model;

[0041] Step 3: The upper mass block connecting plate 5 is installed on the inner surface of the top frame 1, the upper surface is used to install the electromagnet 15, and the mass block 9 is installed on the lower surface. The center of mass of the electromagnet 15 and the mass block 9 are both located in the X-axis direction;

[0042] Step 4: The lower mass block connecting plate 6 is installed on the inner surface of the bottom frame 2, the mass block 9 is installed on the upper surface, and the mass block 8 is installed on the lower surface. The mass centers of mass blocks 8 and 9 are both located in the X-axis direction;

[0043] Step 5: Two separation mechanism mounting plates 19 are fixed on the inner sides of the front and rear lateral frames 3 for mounting and fixing the separation structure 20;

[0044] Step 6: The controller mounting plate 17 is installed on the inner side of the front and rear lateral frames 3, and the controller 16 and the center mass compensation structure 22 are installed on both sides thereof.

[0045] Step 3: Assemble the load 21 and the separation mechanism 20 in the main load-bearing structure of the frame of the ground equivalent test piece, and then adjust the center of mass of the main load-bearing structure of the frame of the ground equivalent test piece by adding the first adjustment mass block 7 and the second adjustment mass block 8 to the main load-bearing structure of the frame of the ground equivalent test piece, and solve the mass of the first adjustment mass block 7 and the second adjustment mass block 8 so that the center of mass coordinates meet the error requirement of ≤3%.

[0046] Calculation method of m2 and m3 corresponding to the first adjustment mass block 7 and the second adjustment mass block 8:

[0047] S31), based on the main load-bearing mechanism of the frame designed in step 2, the separation mechanism 20 and the load 21 are assembled, and the total mass of the mass characteristic parameters of the model analyzed by Solidworks software is: m1, the center of mass coordinates are: (x1, y1, z1), and the origin of the reference coordinate system is located at the geometric center point of the ground equivalent test piece.

[0048] S32), solving the masses of the first adjustment mass block 7 and the second adjustment mass block 8 are: m2, m3;

[0049]

[0050] Among them, h2 is the height of the main load-bearing structure of the frame; l2 is the length of the main load-bearing structure of the frame; (x0, y0, z0) are the center of mass coordinates of the real spacecraft, and (x1, y1, z1) are the center of mass coordinates of the main load-bearing structure of the frame calculated by Solidworks software after assembling the separation mechanism 20 and the load 21 assembly.

[0051] Combination Figure 3 and Figure 4 As shown, the first adjustment mass block 7 is installed on the inner surface of the left lateral frame 4, and its center of mass is located in the Z-axis direction; the second adjustment mass block 8 is installed on the outer surface of the lower mass block connecting plate 6, and its center of mass is located in the X-axis direction.

[0052] Step 4: Two symmetrical first mass blocks 9, second mass block 10, third mass block 11, fourth mass block 12, fifth mass block 13 and sixth mass block 14 are respectively loaded on the outer surfaces in the diagonal directions of the X-axis, Y-axis, Z-axis and XY plane, YZ plane and ZX plane of the frame main load-bearing structure of the ground equivalent test piece in step 3. According to the known actual spacecraft rotational inertia and inertia product parameters, an inertia parameter adjustment method symmetrical along the axial center of mass is adopted. The inertia parameters include the moment of inertia and the inertia product. The masses of the mass blocks 9 to 14 are solved so that the rotational inertia and the inertia product of the ground equivalent test piece are within an error range of ≤3% at this time.

[0053] Furthermore, based on the installation of identical and symmetrical mass blocks on each surface of the main load-bearing structure of the frame in step 3, and the center of mass is located in the axial direction, based on the mass of mass blocks 9 to 14, the inertia parameter adjustment method symmetrical along the axial center of mass is used to adjust the inertia parameter of the ground equivalent test piece and the inertia parameter error of the real micro-spacecraft to ≤3%. The mass calculation method and installation position of mass blocks 9 to 14 are as follows:

[0054] S41), assume that the mass characteristic parameters of the main load-bearing structure of the frame of the ground equivalent test piece described in step 3 after adjusting the center of mass are analyzed by software and the accurate results are as follows:

[0055] Mass: m′0=m1+m2+m3

[0056] Center of mass coordinates: (x2, y2, z2)

[0057] Inertia parameters:

[0058] S42), assuming that the masses of the first mass block 9, the second mass block 10 and the third mass block 11 are adjusted by the moment of inertia along the coordinate X axis, Y axis and Z axis respectively: m4, m5, m6, and the masses of the fourth mass block 12, the fifth mass block 13 and the sixth mass block 14 are adjusted by the diagonal moment of inertia of the XY plane, YZ plane and ZX plane respectively: m7, m8, m9, wherein the mass blocks 9 to 14 are all regular bodies and can be equivalent to the center of mass, and the corresponding center of mass coordinates are (x i ,y i ,z i ), subscript i=4~9.

[0059] Find the mass m of mass blocks 9 to 14 i , mass block number n = 9:

[0060]

[0061]

[0062] This calculation method can effectively calculate the mass of a regular geometric mass block (which can be equivalent to the center of mass point).

[0063] in, It represents the inertia parameters of the main load-bearing structure of the frame after the separation mechanism 20, the load 21 and the mass blocks 7 to 14 are installed. (x2, y2, z2) are the center of mass coordinates of the main load-bearing structure of the frame after the separation mechanism 20, the load 21, the first adjustment mass block 8 and the second adjustment mass block 9 are installed as analyzed by Solidworks software.

[0064] S43), mass blocks 9 to 14 are installed at the corresponding positions of the main load-bearing structure of the ground equivalent test piece frame. Figure 4 and Figure 3 As shown, the first mass block 9 is symmetrically installed on the inner surfaces of the upper mass fast mounting plate 5 and the lower mass block mounting plate 6 along the X-axis, the second mass block 10 is symmetrically installed on the outer surfaces of the front and rear lateral frames 3 along the Y-axis, the third mass block 11 is symmetrically installed on the outer surfaces of the left and right lateral frames 4 along the Z-axis, the fourth mass block 12 is installed on the outer surfaces of the front and rear lateral frames 3 along the XY plane diagonal, the fifth mass block 13 is installed on the outer surface of the column 23 along the YZ plane diagonal, and the sixth mass block 14 is installed on the outer surface of the column 23 along the ZX plane diagonal.

[0065] Step 5: Determine whether the total mass of the ground equivalent test piece after adding mass blocks 7 to 14 meets the requirement of ≤3%. If so, complete the design; otherwise, add mass blocks to the center mass compensation structure 22 until the requirement of ≤3% is met.

[0066] The judgment method is as follows:

[0067] |m'0+2(m4+m5+m6+m7+m8+m9)-m0|≤3%

[0068] The final extended function of the present invention can add the required mass again on the surface of the mass block according to the accuracy required by the test. The mass calculation method is the same as the above steps, so that it can achieve higher accuracy; mass can be added to the central mass compensation structure 22 without affecting the moment of inertia and product of inertia of the model; at the same time, the two symmetrically arranged front and rear lateral frames 3 and the two symmetrically arranged left and right lateral frames 4 can also be translated within a limited range; these extended functions can not only meet more test requirements, but also further improve accuracy.

[0069] Compared with the real model, the quality characteristics of theoretical calculation and software analysis have errors. To avoid error accumulation, the quality characteristic parameters need to be re-analyzed by software each time the above steps are adjusted. After obtaining more accurate quality characteristic parameters, the next step of analysis and design can be carried out. This can greatly reduce errors and reduce the impact of error accumulation on the accuracy of ground test pieces.

[0070] like Figure 1 As shown, in the simulation device, the electromagnet 15 is installed at the top and the center of mass is along the X-axis direction. The purpose of this design is to keep the device in a stable horizontal state to the greatest extent when suspended, and the electrical appliance is unlocked faster with less disturbance; the separation mechanism mounting plate 19 is offset by a certain distance from the center of mass of the entire device, and it can also move in the Y-axis direction along the inner surfaces of the two symmetrically arranged front and rear lateral frames 3. The limitation is that it is connected by screws and can only move horizontally within a limited range; the baffle 18 is installed on the lower mass block connecting plate 6, and the position is between the two loads 21, which is used to simulate the actual situation of the spacecraft door opening and blocking.

Claims

1. A method for designing a ground equivalent test piece for simulating the mass characteristics of a micro-spacecraft, characterized in that: The design steps are as follows: Step 1: The experimental objects include two sets of separation mechanisms (20) and two loads (21). The physical assembly objects and their size parameters of the two sets of separation mechanisms (20) and the two loads (21) are obtained, and the actual mass characteristic parameters of the micro-spacecraft are obtained at the same time. It is assumed that the error of the ground equivalent test piece is ≤3%, the X axis is the direction of the load launch, the Y axis is parallel to the short side of the top frame (1), +Z is determined by +X and +Y is determined by the right-hand rule, and the coordinate system of the ground equivalent test piece is consistent with the actual spacecraft; Step 2: According to the size parameters of the two sets of separation mechanisms (20) and the two loads (21) assembly and the actual mass characteristic parameters of the micro-spacecraft, the ground equivalent test piece is determined to be a cubic structure and the length, width and height dimensions. The actual mass characteristic parameters of the micro-spacecraft include mass, center of mass coordinates, moment of inertia and product of inertia. The cubic structure is convenient for installing mass blocks to adjust the mass, center of mass, moment of inertia and product of inertia. The frame main bearing structure of the ground equivalent test piece is designed according to the experimental requirements; The main load-bearing structure of the frame of the ground equivalent test piece comprises: a top frame (1), a bottom frame (2), an upper mass block connecting plate (5), a lower mass block connecting plate (6), an electromagnet (15), an electric controller (16), an electric controller mounting plate (17), a baffle (18), a central mass compensation structure (22), two separation mechanism mounting plates (19), two symmetrically arranged front and rear lateral frames (3), two symmetrically arranged left and right lateral frames (4), and four columns (23); Step 3: Assemble the load (21) and the separation mechanism (20) in the main load-bearing structure of the frame of the ground equivalent test piece, and then adjust the center of mass of the main load-bearing structure of the frame of the ground equivalent test piece by adding a first adjustment mass block (7) and a second adjustment mass block (8) to the main load-bearing structure of the frame of the ground equivalent test piece, and solve the mass of the first adjustment mass block (7) and the second adjustment mass block (8) so that the center of mass coordinates of the main load-bearing structure of the frame of the ground equivalent test piece at this time meet the error requirement of ≤3%; Step 4: Based on the main load-bearing structure of the frame of the ground equivalent test piece in step 3, two symmetrical first mass blocks (9), second mass blocks (10), third mass blocks (11), fourth mass blocks (12), fifth mass blocks (13), and sixth mass blocks (14) are respectively installed on the outer surfaces in the diagonal directions of the X-axis, Y-axis, Z-axis, XY plane, YZ plane, and ZX plane. According to the known parameters of the actual spacecraft moment of inertia and product of inertia, an inertia parameter adjustment method symmetrical along the axial center of mass is adopted. The inertia parameters include the moment of inertia and product of inertia. The masses of the mass blocks (9-14) are solved so that the moment of inertia and product of inertia of the ground equivalent test piece at this time are within an error range of ≤3%; Step 5: Determine whether the total mass error of the ground equivalent test piece after adding the mass blocks (7-14) meets the requirement of ≤3%. If so, complete the design; otherwise, add mass blocks to the central mass compensation structure (22) until the requirement of ≤3% is met.

2. The method for designing a ground equivalent test piece for simulating the mass characteristics of a micro-spacecraft according to claim 1, characterized in that: In step 1, after the separation structure (20) and the load (21) are assembled, the necessary parameters of the ground equivalent test piece are measured, including the height h1, the maximum diameter d1, and the installation distance l1 of the two loads, where h1 is used to determine the frame height range, d1 is used to design the separation mechanism mounting plate (19) that carries the assembly, and l1 is used to determine the frame width; The mass characteristic parameters of the real spacecraft are known: Mass: m0, unit: kg; The coordinates of the center of mass are: (x0, y0, z0), unit: mm; Inertia parameters: Unit: kg / mm 2 ; It is required that the errors of various parameters of the mass characteristics of the designed ground equivalent test piece and the actual spacecraft parameters are ≤3%, the X-axis is the load launch direction, the Y-axis is parallel to the short side of the top frame (1), +Z is determined by +X and +Y by the right-hand rule, and the coordinate system of the ground equivalent test piece is consistent with the actual spacecraft.

3. The method for designing a ground equivalent test piece for simulating the mass characteristics of a micro-spacecraft according to claim 2, characterized in that: In step 2, the basic dimensions of the cubic test piece frame are length l2, width w2, and height h2, where: w2>l1+d1, h1<h2<h1+140, the unit is mm, and the length l2 is determined according to actual needs. The main load-bearing structure of the frame of the ground equivalent test piece is designed according to the experimental requirements.

4. The method for designing a ground equivalent test piece for simulating the mass characteristics of a micro-spacecraft according to claim 3, characterized in that: In step 2, the main load-bearing structure of the frame of the ground equivalent test piece includes a top frame (1), a bottom frame (2), an upper mass block connecting plate (5), a lower mass block connecting plate (6), an electromagnet (15), an electric controller (16), an electric controller mounting plate (17), a baffle (18), a central mass compensation structure (22), two separation mechanism mounting plates (19), two symmetrically arranged front and rear lateral frames (3), two symmetrically arranged left and right lateral frames (4), and four columns (23), wherein the four columns (23) serve as supports, and the top frame (1), the bottom frame (2), the front and rear lateral frames (3) and the lower mass block connecting plate (6) are respectively connected to the top frame (1), the bottom frame (2), the front and rear lateral frames (3) and the lower mass block connecting plate (6), an electromagnet (15), an electric controller (16), an electric controller mounting plate (17), a baffle (18), a central mass compensation structure (22), two separation mechanism mounting plates (19), two symmetrically arranged front and rear lateral frames (3), and two symmetrically arranged left and right lateral frames (4). The left and right lateral frames (4), the upper mass block connecting plate (5) is fixed on the top frame (1), the lower mass block connecting plate (6) is fixed on the bottom frame (2), the baffle (18) is fixed on the lower mass block connecting plate (6), the electric controller mounting plate (17), the central mass compensation structure (22), and the two separation mechanism mounting plates (19) are all fixed between the two front and rear lateral frames (3), and the two separation mechanism mounting plates (19) are parallel to the top frame (1), the electric controller (16) and the central mass compensation structure (22) are all fixed on the electric controller mounting plate (17), and the electromagnet (15) is fixed on the upper mass block connecting plate (5) and is located on the X-axis.

5. The method for designing a ground equivalent test piece for simulating the mass characteristics of a micro-spacecraft according to claim 4, characterized in that: In step 3, the centroid of the main load-bearing structure of the frame of the ground equivalent test piece is adjusted, and the masses of the first adjustment mass block (7) and the second adjustment mass block (8) are solved so that the centroid coordinates of the main load-bearing structure of the frame of the ground equivalent test piece meet the error requirement of ≤3%, as follows: The calculation method of the masses m2 and m3 corresponding to the first adjustment mass block (7) and the second adjustment mass block (8) is as follows: S31), the overall mass of the mass characteristic parameters of the model of the main load-bearing structure of the frame designed in step 2 after the assembly of the separation mechanism (20) and the load (21) is calculated by Solidworks software: m1, the center of mass coordinates are: (x1, y1, z1), and the origin of the reference coordinate system is located at the geometric center point of the ground equivalent test piece; S32), solving the masses of the first regulating mass block (7) and the second regulating mass block (8) as: m2, m3 respectively; Wherein, h2 is the height of the main bearing structure of the frame; l2 is the length of the main bearing structure of the frame; (x0, y0, z0) is the coordinate of the center of mass of the real spacecraft, and (x1, y1, z1) is the coordinate of the center of mass of the main bearing structure of the frame analyzed by Solidworks software after assembling the separation mechanism (20) and the load (21) assembly; The first adjustment mass block (7) is mounted on the inner surface of the left lateral frame (4), and its center of mass is located in the Z-axis direction; the second adjustment mass block (8) is mounted on the outer surface of the lower mass block connecting plate (6), and its center of mass is located in the X-axis direction.

6. The method for designing a ground equivalent test piece for simulating the mass characteristics of a micro-spacecraft according to claim 5, characterized in that: In step 4, two symmetrical first mass blocks (9), second mass blocks (10), third mass blocks (11), fourth mass blocks (12), fifth mass blocks (13), and sixth mass blocks (14) are respectively loaded on the outer surfaces of the main load-bearing structure of the frame of the ground equivalent test piece in step 3 in the diagonal directions of the X-axis, Y-axis, Z-axis, XY plane, YZ plane, and ZX plane. According to the known actual spacecraft rotational inertia and inertia product parameters, an inertia parameter adjustment method symmetrical along the axial center of mass is adopted. The inertia parameters include the rotational inertia and the inertia product. The mass of the mass blocks (9-14) is solved so that the rotational inertia and the inertia product of the ground equivalent test piece at this time are within an error range of ≤3%, as follows: Based on the installation of identical and symmetrical mass blocks on each surface of the main load-bearing structure of the frame in step 3, and the center of mass is located in the axial direction, based on the mass of the mass blocks (9-14), the inertia parameter adjustment method symmetrical along the axial center of mass is used to adjust the inertia parameters of the ground equivalent test piece and the inertia parameters of the real micro-spacecraft to an error of ≤3%. The mass calculation method and installation position of the mass blocks (9-14) are as follows: S41), assume that the quality parameters of the main load-bearing structure of the ground equivalent test piece frame after adjusting the centroid in step 3 are analyzed by the software and the accurate results are as follows: Mass: m'0 = m1 + m2 + m3 Center of mass coordinates: (x2, y2, z2) Inertia parameters: S42), assuming that the masses of the first mass block (9), the second mass block (10), and the third mass block (11) are adjusted by the moment of inertia symmetrically along the coordinate X axis, Y axis, and Z axis: m4, m5, and m6 respectively, and the masses of the fourth mass block (12), the fifth mass block (13), and the sixth mass block (14) are adjusted by the moment of inertia of the diagonal lines of the XY plane, the YZ plane, and the ZX plane: m7, m8, and m9 respectively, wherein the mass blocks (9 to 14) are all regular bodies and can be equivalent to the center of mass points, and the corresponding center of mass point coordinates are (x i ,y i ,z i ), subscript i = 4 to 9; Solve for the mass m corresponding to the mass block (9-14) i , mass block number n = 9 This calculation method can effectively calculate the mass of a regular geometric mass block (which can be equivalent to the center of mass point); in, The invention relates to an inertia parameter of the main load-bearing structure of the frame after the separation mechanism (20), the load (21) and the mass blocks (7-14) are installed; (x2, y2, z2) are the coordinates of the center of mass of the main load-bearing structure of the frame after the separation mechanism (20), the load (21), the first adjustment mass block (8) and the second adjustment mass block (9) are installed; S43), the first mass block (9) is symmetrically installed on the inner surface of the upper mass fast mounting plate (5) and the lower mass block mounting plate (6) along the X axis, the second mass block (10) is symmetrically installed on the outer surface of the front and rear lateral frames (3) along the Y axis, the third mass block (11) is symmetrically installed on the outer surface of the left and right lateral frames (4) along the Z axis, the fourth mass block (12) is installed on the outer surface of the front and rear lateral frames (3) along the XY plane diagonal, the fifth mass block (13) is installed on the outer surface of the column (23) along the YZ plane diagonal, and the sixth mass block (14) is installed on the outer surface of the column (23) along the ZX plane diagonal.

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