A variable-parameter satellite vibration isolator and vibration isolation method

Abstract

The present invention specifically relates to a variable-parameter satellite vibration isolator and an isolation method. The vibration isolator includes a thermistor, a metal shell, a resistance wire, a filling polymer, a connector, an upper fixed support, a heat insulation component, a lower fixed support and a wire; the filling polymer, the connector, the upper fixed support and the lower fixed support are all annular structures. The outer surface of the connector is connected to the inner wall of the upper fixed support. The outer wall of the upper fixed support is connected to the inner wall of the upper half of the filling polymer. The outer wall of the lower fixed support is connected to the inner wall of the lower half of the filling polymer. The inner wall of the lower fixed support and the bottom of the connector and the bottom of the upper half of the filling polymer enclose a bolt installation cavity. The outer wall of the filling polymer is provided with a metal shell. A resistance wire is wound around the outside of the metal shell. A heat insulation component is provided outside the resistance wire. The satellite control unit is connected to the thermistor and the resistance wire respectively through two wires.

Description

Technical Field

[0001] The present invention relates to the technical field of spacecraft mechanics, and particularly relates to a variable-parameter satellite vibration isolator and an isolation method. Background Art

[0002] The mechanical environment conditions of a satellite mainly consist of three aspects: ground assembly-test conditions, rocket launch conditions, and on-orbit conditions. Among them, during the rocket launch phase, the satellite has to withstand mechanical environments such as quasi-static overload, transient environments (low-frequency transient environments during ignition of rocket engines at all levels and high-frequency transient environments during ignition of pyrotechnics on the satellite), random vibration, and acoustic environment. The mechanical environment in this stage is complex, with multiple vibration characteristics, a wide frequency range, and large amplitudes. If not properly dealt with, it will cause structural instability, deformation, and fracture damage to the satellite structure, resulting in loosening and detachment of instrument equipment, pipelines, and cables, and performance parameter drift, out-of-tolerance, and even failure of electronic devices. When the satellite is in orbit, it mostly withstands a quasi-periodic vibration environment. For example, satellite rotating mechanisms such as on-board momentum wheels, control moment gyros, solar panel drive assemblies, and antenna turntables have different operating rotation speeds, small disturbance amplitudes, and a relatively wide frequency distribution, which are prone to cause structural coupling.

[0003] Existing vibration isolation devices for satellites during the rocket launch phase and on-orbit working phase are mainly divided into two categories. The first is a passive vibration isolation device with materials as the core, such as silicone rubber vibration isolators, wire rope vibration isolators, wire spring vibration isolators, etc. The disadvantage of passive vibration isolation devices is low vibration isolation efficiency, and they can only be designed for one or several working conditions. Usually, there is only one fixed vibration isolation frequency (for a second-order system), and the damping ratio is also a fixed value. The second is semi-active and active vibration isolation devices based on various driving methods, such as Stewart mechanisms, electromagnetic mechanisms, etc. The disadvantages are complex structure, high cost, low reliability, and limited use during the satellite launch phase. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art, so as to provide an intelligent variable-parameter satellite vibration isolator and an isolation method.

[0005] A variable-parameter satellite vibration isolator includes a thermistor, a metal shell, a resistance wire, a filled polymer, a connector, an upper fixed support, a heat insulation component, a lower fixed support, and a wire;

[0006] The filling polymer, connector, upper fixed support, and lower fixed support are all annular structures. The connector is provided with a through hole. The outer surface of the connector is connected to the inner wall of the upper fixed support in a matching manner. The outer wall of the upper fixed support is connected to the inner wall of the upper half of the filling polymer in a matching manner. The outer wall of the lower fixed support is connected to the inner wall of the lower half of the filling polymer in a matching manner. The bottom of the lower fixed support is provided with a through hole, which is coaxial with the through hole on the connector. The inner wall of the lower fixed support, the bottom of the connector, and the bottom of the upper half of the filling polymer enclose a bolt installation cavity. The outer wall of the filling polymer is provided with a metal shell, and a resistance wire is wound around the outside of the metal shell. At least one layer of heat insulation component is provided outside the resistance wire. The upper surface of the thermistor is connected to the bottom of the metal shell, the filling polymer, and the lower fixed support. The satellite control unit is connected to the thermistor and the resistance wire respectively through two wires. The thermistor, the resistance wire, and the satellite control unit jointly form a heating and temperature measurement circuit to heat and measure the temperature of the filling polymer.

[0007] Furthermore, the filling polymer is made of silicone rubber, butyl rubber, epoxy resin, or polyurethane material.

[0008] Furthermore, the filling polymer is silicone rubber, and a softening agent and a plasticizer are added during the processing of the silicone rubber.

[0009] Furthermore, the glass transition temperature range of the silicone rubber is 25°C - 30°C, and the temperature width ΔT = 5°C.

[0010] Furthermore, the filling polymer is poured in a liquid form into the metal cavity surrounded by the metal shell, the connector, the upper fixed support, and the lower fixed support in a high-temperature environment and cooled and solidified to form a shape.

[0011] A vibration isolation method based on the variable-parameter satellite isolator described in any one of the above items is as follows: First, conduct a ground test to obtain a speed-frequency-amplitude data table of the satellite rotation mechanism in the working speed mode, select the material of the filling polymer, and obtain the elastic modulus E and damping ratio ζ of the material in the temperature range of t 1 ~t 2 , where t 1 is the temperature during the satellite launch stage, and t 2is the highest temperature of the variable parameter satellite vibration isolator; input the above two data tables into the mathematical model of vibration isolation, and calculate the corresponding elastic modulus E and damping ratio ζ required for each rotational speed of the satellite rotating mechanism to reach a reasonable vibration isolation index according to the mathematical model of vibration isolation, so as to obtain a comparison table of temperature t and the rotational speed ω of the satellite rotating mechanism; after the satellite is in orbit, the satellite control unit reads the comparison table and the rotational speed ω of the satellite rotating mechanism, and sends a temperature control command to the heating wire according to the corresponding relationship between the current rotational speed ω of the satellite rotating mechanism and the comparison table. When heating is required, the heating wire heats the variable parameter satellite vibration isolator, and the thermistor collects the temperature of the filled polymer and transmits the temperature signal to the satellite control unit.

[0012] Advantages of the present invention:

[0013] In the technical solution of the present invention, the satellite control unit can perform autonomous heating and temperature acquisition control on the filled polymer in the vibration isolator according to the vibration isolation requirements, so as to obtain the optimal elastic modulus and damping ratio of the vibration isolator. On-orbit vibration isolation does not require manual intervention and realizes fully autonomous operation. It is an intelligent vibration isolation with the characteristics of high vibration isolation efficiency and good stability. It is a vibration isolation device with light weight, small volume, easy operation and easy implementation.

[0014] The filled polymer in the present invention can design the material properties of the rubber according to the vibration isolation parameter requirements of the system, so that the present vibration isolator has a wide range of applications and can be applied to the vibration isolation during satellite launch and on-orbit stages. It can be installed on mechanisms such as on-board momentum wheels, control moment gyros, solar panel drive assemblies, and antenna turntables on the satellite. Description of the drawings

[0015] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 is a sectional view of the variable parameter satellite vibration isolator of the present invention;

[0017] Figure 2 is an assembly drawing of the variable parameter satellite vibration isolator and the satellite rotating mechanism;

[0018] Figure 3 is a damping and stiffness curve graph of silicone rubber material;

[0019] Figure 4 is a comparison graph of the absolute transmissibility of the variable parameter satellite vibration isolator;

[0020] Figure 5 is the working process of the variable parameter satellite vibration isolator.

[0021] Description of the reference numerals:

[0022] 1 - Thermistor; 2 - Metal shell; 3 - Resistance wire;

[0023] 4 - Filled polymer; 5 - Connector; 6 - Upper fixed support;

[0024] 7 - Heat insulation component; 8 - Lower fixed support; 9 - Conducting wire;

[0025] 10 - Satellite rotation mechanism; 11 - Variable - parameter satellite vibration isolator; 12 - Satellite control unit. Detailed implementation manners

[0026] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] The specific target of the present invention is those satellite rotating mechanisms that are sensitive to external vibrations and output disturbing vibrations externally. The present invention proposes a variable-parameter vibration isolator, which can meet the vibration isolation requirements during the satellite launch stage and, during the on-orbit stage, maximize the attenuation of the disturbing force / moment of the satellite rotating mechanism, providing a more stable mechanical working environment for on-board equipment;

[0031] Please refer to Figure 1 and Figure 2 , a variable-parameter satellite vibration isolator, comprising a thermistor 1, a metal shell 2, a resistance wire 3, a filling polymer 4, a connector 5, an upper fixed support 6, a heat insulation component 7, a lower fixed support 8, and a wire 9;

[0032] The filling polymer 4, the connector 5, the upper fixed support 6, and the lower fixed support 8 are all of annular structures. The connector 5 is provided with a through hole. The outer surface of the connector 5 is connected to the inner wall of the upper fixed support 6. The outer wall of the upper fixed support 6 is connected to the inner wall of the upper half of the filling polymer 4. The outer wall of the lower fixed support 8 is connected to the inner wall of the lower half of the filling polymer 4. The bottom of the lower fixed support 8 is provided with a through hole, which is coaxial with the through hole on the connector 5. The inner wall of the lower fixed support 8 and the bottom of the connector 5 and the bottom of the upper half of the filling polymer 4 enclose a bolt installation cavity. The outer wall of the filling polymer 4 is provided with a metal shell 2. The metal shell 2 is externally wound with a resistance wire 3. At least one layer of heat insulation component 7 is provided outside the resistance wire 3. The upper surface of the thermistor 1 is connected to the bottoms of the metal shell 2, the filling polymer 4, and the lower fixed support 8. The satellite control unit 12 is connected to the thermistor 1 and the resistance wire 3 respectively through two wires 9. The thermistor 1, the resistance wire 3, and the satellite control unit 12 together form a heating and temperature measurement circuit to heat and measure the temperature of the filling polymer 4. The elastic modulus and damping ratio of the filling polymer 4 are related to temperature. During the ground test stage, a rotational speed-frequency-amplitude data table of the satellite rotating mechanism 10 in the working speed mode is obtained. The material of the filling polymer 4 is selected and the data table of the elastic modulus E and damping ratio ζ of this material in the temperature range of t 1 ~t 2 is obtained, where t 1 is the temperature during the satellite launch stage, and t 2is the highest temperature of the variable parameter satellite vibration isolator 11; input the above two data tables into the mathematical model of vibration isolation, and calculate the elastic modulus E and damping ratio ζ corresponding to each rotational speed of the satellite rotating mechanism 10 to achieve reasonable vibration isolation indexes according to the mathematical model of vibration isolation, so as to obtain a comparison table of temperature t and rotational speed ω of the satellite rotating mechanism 10; after the satellite is in orbit, the satellite control unit 12 reads the comparison table and the rotational speed ω of the satellite rotating mechanism 10, and sends a temperature control command to the heating wire 3 according to the corresponding relationship between the current rotational speed ω of the satellite rotating mechanism 10 and the comparison table. When heating is required, the heating wire 3 heats the variable parameter satellite vibration isolator 11, and the thermistor 1 collects the temperature of the filled polymer 4 and transmits the temperature signal to the satellite control unit 12; through the satellite control unit 12 querying the rotational speed ω of the satellite rotating mechanism 10 in orbit in a cycle, the satellite control unit 12 automatically sets the heating target temperature of the heating wire 3, and finally realizes intelligent vibration isolation. This process does not require manual intervention, and the vibration isolation requirements can be automatically realized after the satellite is in orbit.

[0033] The core of the variable parameter satellite vibration isolator is the filled polymer 4. The filled polymer 4 can be silicone rubber, butyl rubber, epoxy resin or polyurethane material. In this embodiment, silicone rubber is selected. Silicone rubber material is a kind of polymer matrix composite material, which is made of rubber polymer as the matrix material and adding different compounding systems and filler systems. Its mechanical properties are closely related to the composition and microstructure of the material. The main chain of the silicone rubber molecule is composed of silicon and oxygen atoms. The energy dissipation ability of the rubber mainly comes from the friction between the molecular chain segments. On the one hand, during the vulcanization process of the matrix rubber, by controlling the type and content of the vulcanizing agent, the cross-linking network structure and cross-linking density can be changed. As the cross-linking density increases, the modulus value of the material increases while the loss factor decreases; on the other hand, softeners and plasticizers are added during the rubber processing process. The plasticizer can adjust the glass transition temperature of the rubber, and then improve the damping performance of the material near the working temperature. Organic polar small molecules can be added to the rubber molecules, and the interaction between the rubber molecules and the small molecules can be used to improve the damping of the material and improve the position and width of the damping peak of the material. Therefore, according to the vibration isolation parameter requirements of the system, the material characteristics of the rubber can be designed to realize the corresponding relationship between the material temperature and the parameters.

[0034] The glass transition temperature range of the silicone rubber in this embodiment is 25°C - 30°C, and the temperature width ΔT = 5°C. The temperature during the satellite launch stage is t 1 (the upper limit value of the temperature inside the fairing), at this time the mechanical parameters of the vibration isolator rubber are S 1 (t 1 , E 1 , ζ 1 ), that is, under the temperature environment of the fairing temperature, the elastic modulus of the material is E 1 , and the damping ratio is ζ 1 ; when the satellite is in orbit, the highest temperature of the vibration isolator is t2 , corresponding to the vibration isolator parameter S 2 (t 2 , E 2 , ζ 2 ), the elastic modulus of the material at this temperature is E 2 , and the damping ratio is ζ 2 . There is the following relationship E 1 > E 2 , ζ 1 < ζ 2 . After the satellite is in orbit, the temperature of the vibration isolator can be adjusted within the range of t 1 ~t 2 . The damping and stiffness curves of the silicone rubber material are as shown in Figure 3 .

[0035] This variable-parameter satellite vibration isolator is installed between the satellite rotating mechanism 10 and the satellite platform. During installation, first connect the lower fixed support 8 of the vibration isolator to the satellite platform, and then connect the satellite rotating mechanism 10 to the upper fixed support 6 of the vibration isolator. The standard torque is used during installation; the satellite platform provides mechanical and electrical interfaces for the vibration isolator and provides a heating current of 5V1A. When the satellite rotating mechanism 10 is working, it can generate a vibration disturbance output related to the rotational speed Ω, expressed as F(Ω, ω). The vibration disturbance frequency distribution range is relatively wide and has a certain universality.

[0036] According to the transfer ratio formula of the single-degree-of-freedom vibration isolation system:

[0037]

[0038] In the formula: ζ is the damping ratio ζ = c / c c , c is the damping coefficient, c c is the critical damping coefficient, λ is the frequency ratio λ = ω j / ω n , ω j is the excitation frequency, ω n is the natural frequency of the system. T is the transfer efficiency of the vibration isolation system. The smaller T is, the higher the vibration isolation efficiency and the better the effect.

[0039] Take Figure 3 the rubber material parameters S 1 (t 1 , E 1 , ζ 1 ), S 2 (t 2 , E 2 , ζ 2 ). The designed natural frequencies of the vibration isolation system are ω n1 , ω n2 . Since E 1 > E 2 , then the corresponding natural frequency ω of the vibration isolation systemn1 > ω n2 。 Substitute S 1 (t 1 , E 1 , ζ 1 ) and S 2 (t 2 , E 2 , ζ 2 ) and ω n1 , ω n2 into Equation (1). The comparison of the absolute transmissibility of the vibration isolator is as Figure 4 shown. By appropriately controlling the operating temperature of the silicone rubber, T s2 (t 2 , E 2 , ζ 2 ) << T s1 (t 1 , E 1 , ζ 1 ), which can greatly improve the vibration isolation efficiency of the system.

[0040] The overall structure of the variable parameter satellite vibration isolator is a thermosetting elastomer. During processing, at high temperature, the metal shell 2, the connector 5, the upper fixed support 6 and the lower fixed support 8 are installed at fixed positions in the mold. The filling polymer 4 is poured into the metal cavity surrounded by the metal shell 2, the connector 5, the upper fixed support 6 and the lower fixed support 8 in liquid form and cooled and solidified. Then other components are successively installed, and after assembly, the performance tests of the resistance wire 3 and the thermistor 1 are carried out.

[0041] The variable parameter satellite vibration isolator can also be applied to mechanisms such as on - satellite momentum wheels, control moment gyroscopes, solar panel drive assemblies, and antenna turntables on satellites.

[0042] Please refer to Figure 5 . The present invention also includes a vibration isolation method based on the variable parameter satellite vibration isolator described in any one of the above. Specifically, first, a ground test is carried out to obtain the rotational speed - frequency - amplitude data table of the satellite rotating mechanism 10 in the working speed mode. Select the material of the filling polymer 4 and obtain the data table of the elastic modulus E and damping ratio ζ of this material in the temperature range of t 1 to t 2 , where t 1 is the temperature during the satellite launch phase, and t 2is the highest temperature of the variable parameter satellite vibration isolator 11; input the above two data tables into the mathematical model of vibration isolation, and calculate the elastic modulus E and damping ratio ζ corresponding to each rotational speed of the satellite rotating mechanism 10 to achieve reasonable vibration isolation indexes according to the mathematical model of vibration isolation, so as to obtain a comparison table of temperature t and rotational speed ω of the satellite rotating mechanism 10; after the satellite is in orbit, the satellite control unit 12 reads the comparison table and the rotational speed ω of the satellite rotating mechanism 10, and issues a temperature control command to the heating wire 3 according to the corresponding relationship between the current rotational speed ω of the satellite rotating mechanism 10 and the comparison table. When heating is required, the heating wire 3 heats the variable parameter satellite vibration isolator 11, and the thermistor 1 collects the temperature of the filling polymer 4 and transmits the temperature signal to the satellite control unit 12.

[0043] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A variable-parameter satellite vibration isolator, characterized in that, it includes a thermistor (1), a metal shell (2), a resistance wire (3), a filling polymer (4), a connector (5), an upper fixed support (6), a heat insulation component (7), a lower fixed support (8) and a wire (9); The filling polymer (4), the connector (5), the upper fixed support (6) and the lower fixed support (8) are all annular structures. The connector (5) is provided with a through hole. The outer surface of the connector (5) is connected with the inner wall of the upper fixed support (6). The outer wall of the upper fixed support (6) is connected with the inner wall of the upper half of the filling polymer (4). The outer wall of the lower fixed support (8) is connected with the inner wall of the lower half of the filling polymer (4). The bottom of the lower fixed support (8) is provided with a through hole, which is coaxial with the through hole on the connector (5). The inner wall of the lower fixed support (8) and the bottom of the connector (5) and the bottom of the upper half of the filling polymer (4) enclose a bolt installation cavity. The outer wall of the filling polymer (4) is provided with a metal shell (2). The metal shell (2) is externally wound with a resistance wire (3). At least one layer of heat insulation component (7) is provided outside the resistance wire (3). The upper surface of the thermistor (1) is connected with the bottoms of the metal shell (2), the filling polymer (4) and the lower fixed support (8). The satellite control unit (12) is connected to the thermistor (1) and the resistance wire (3) respectively through two wires (9). The thermistor (1), the resistance wire (3) and the satellite control unit (12) together form a heating and temperature measurement circuit to heat and measure the temperature of the filling polymer (4); The filling polymer (4) is made of silicone rubber, butyl rubber, epoxy resin or polyurethane material. When the filling polymer (4) is silicone rubber, a softening agent and a plasticizer are added during the processing of the silicone rubber; The glass transition temperature range of the silicone rubber is 25°C - 30°C, and the temperature width ΔT = 5°C; The filling polymer (4) is poured in a liquid form into the metal cavity surrounded by the metal shell (2), the connector (5), the upper fixed support (6) and the lower fixed support (8) in a high-temperature environment and cooled and solidified into shape.

2. A vibration isolation method based on the variable-parameter satellite vibration isolator according to claim 1, characterized in that, The specific steps are as follows: First, conduct a ground test to obtain the rotational speed-frequency-amplitude data table of the satellite rotating mechanism (10) in the working rotational speed mode, select the material of the filled polymer (4) and obtain the data table of the elastic modulus E and damping ratio ζ of this material in the temperature range of t 1 ~t 2 , where t 1 is the temperature during the satellite launch stage, and t 2 is the highest temperature of the variable parameter satellite vibration isolator (11); input the above rotational speed-frequency-amplitude data table and the data table of the elastic modulus E and damping ratio ζ into the vibration isolation mathematical model, calculate the elastic modulus E and damping ratio ζ corresponding to each rotational speed of the satellite rotating mechanism (10) to achieve reasonable vibration isolation indicators according to the vibration isolation mathematical model, and obtain the comparison table of temperature t and the rotational speed ω of the satellite rotating mechanism (10); after the satellite is in orbit, the satellite control unit (12) reads the comparison table and the rotational speed ω of the satellite rotating mechanism (10), and sends a temperature control instruction to the heating wire (3) according to the corresponding relationship between the current rotational speed ω of the satellite rotating mechanism (10) and the comparison table. When heating is required, the heating wire (3) heats the variable parameter satellite vibration isolator (11), and the thermistor (1) collects the temperature of the filled polymer (4) and transmits the temperature signal to the satellite control unit (12).

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