Microgravity simulation device for ground test of spacecraft component

Abstract

The invention belongs to the technical field of spacecraft ground test equipment, and particularly relates to a microgravity simulation device for spacecraft component ground test, which comprises a base, an air floatation support mechanism, an ultrasonic standing wave stabilization mechanism, a self-adaptive clamping mechanism, a servo drive error compensation mechanism, a control system and a test platform. The air floatation supporting mechanism provides vertical non-contact supporting force to offset gravity, the ultrasonic stabilizing mechanism maintains horizontal stability, the self-adaptive clamping mechanism is adaptive to parts of multiple sizes, and the servo compensation mechanism corrects deviation in real time. The composite suspension structure is combined with PID-fuzzy closed-loop control, the simulation error is controlled within 4.0%, the defects that existing equipment is low in precision, short in time, prone to pollution and poor in universality are overcome, long-time stable simulation can be achieved, and reliable support is provided for part ground verification.

Description

Technical Field

[0001] This invention belongs to the technical field of spacecraft ground testing equipment, specifically relating to a microgravity simulation device for ground testing of spacecraft components. Background Technology

[0002] The on-orbit performance of spacecraft components is highly dependent on the microgravity environment in space. During ground testing, microgravity simulation devices are needed to reproduce the effects of microgravity in space to accurately verify the structural reliability, functional stability, and operational precision of components, thus ensuring the safety of spacecraft operation in orbit. The "National Medium- and Long-Term Development Plan for Space Science (2024-2050)" proposes to strengthen innovation in spacecraft ground testing technologies, break through key technologies such as high-precision microgravity simulation, and support the industrialization of small spacecraft. Currently, microgravity simulation technologies for ground testing of spacecraft components both domestically and internationally are mainly divided into three categories: acceleration control, physical support, and suspension methods. All of these technologies have significant shortcomings and cannot meet the high-efficiency, high-precision testing requirements of precision components for small spacecraft. Specific problems are as follows:

[0003] (a) Acceleration control devices (such as drop towers and electromagnetic catapults): These devices simulate microgravity by controlling the movement of the experimental platform to generate reverse acceleration. Although they can reproduce the microgravity state relatively realistically, they have a fatal flaw of extremely short simulation time. The effective microgravity time of drop tower devices is usually only 3.6 seconds, and the longest electromagnetic catapult device is only 4 seconds. They cannot complete long-term static performance tests of small spacecraft precision components (such as micro sensors) (usually more than 30 minutes). Moreover, the equipment is bulky (traditional drop towers are over 100m high), has high manufacturing costs (a single unit costs more than 50 million yuan), and low experimental efficiency (traditional drop towers can only complete 2-3 experiments a day). They are not suitable for batch component testing.

[0004] (ii) Physical support devices (such as suspension and water flotation methods): These devices achieve microgravity simulation by using physical support to counteract gravity. However, they inevitably come into direct contact with the test components, which can easily cause wear and contamination on the surface of the components. They are especially unsuitable for testing components related to space metal 3D printing, precision sensors, and other parts that are easily contaminated. At the same time, the suspension method is affected by the elastic deformation of the rope (deformation error can reach 0.5mm), and the water flotation method is affected by the liquid resistance (resistance error can reach 1.2N). Both of these result in low accuracy of microgravity simulation, with the maximum force compensation error reaching 13.9%, which cannot meet the requirements of high-precision testing (requiring an error of ≤5.0%).

[0005] (III) Single suspension devices (such as air-floating and ultrasonic standing wave suspension): Air-floating devices use high-pressure gas to form an air film to support the test component. However, they have problems such as uneven air film thickness (fluctuation range 0.03-0.15mm) and poor vertical stability, which can easily cause component displacement (the displacement can reach 0.8mm). Ultrasonic standing wave suspension devices can only maintain the horizontal stability of the test component and cannot achieve effective vertical support. Both lack real-time error compensation mechanisms and are easily affected by external interference (such as airflow and vibration) during the simulation process, resulting in fluctuations in simulation accuracy (fluctuation range ±2.1%). They cannot be adapted to small spacecraft components of different sizes and weights and have poor versatility.

[0006] (iv) Existing composite suspension devices: Although some composite suspension systems combine the advantages of air buoyancy and ultrasonic standing waves, they are not equipped with efficient error compensation mechanisms, resulting in problems such as inconsistent stiffness and insufficient compensation accuracy due to friction. At the same time, their range of motion is limited (usually only 800mm), making them unsuitable for small spacecraft components of different sizes (size range 50-500mm). Furthermore, their control algorithm has a slow response speed (response time ≥0.5s), making it impossible to dynamically correct microgravity simulation deviations and failing to meet diverse testing needs.

[0007] In summary, existing microgravity simulation devices generally suffer from problems such as low simulation accuracy, short simulation time, poor versatility, easy contamination of test components, and low experimental efficiency. These issues have become key bottlenecks restricting the improvement of ground testing quality for precision components of small spacecraft, and cannot meet the ground verification requirements of high reliability, high precision, and high efficiency for spacecraft components. Therefore, it is urgent to design a microgravity simulation device that can solve the above problems. Summary of the Invention

[0008] This invention provides a microgravity simulation device for ground testing of spacecraft components. The aim is to address the shortcomings of existing microgravity simulation technologies, such as low accuracy, short simulation time, poor versatility, easy contamination of test components, and low experimental efficiency. This invention provides a microgravity simulation device for ground testing of spacecraft components that combines a composite suspension structure with closed-loop error compensation control. Based on precise control formulas and optimized parameters, it achieves long-term, high-precision, non-contact microgravity simulation, improving the device's versatility and experimental efficiency. It is adaptable to the ground testing needs of various precision components in small spacecraft, reduces testing costs, and provides reliable technical support for on-orbit performance verification of spacecraft components.

[0009] The above objectives are achieved through the following technical solutions:

[0010] A microgravity simulation device for ground testing of spacecraft components includes a base, an air-bearing support mechanism, an ultrasonic standing wave stabilization mechanism, an adaptive clamping mechanism, a servo-driven error compensation mechanism, a control system, and a test platform. The air-bearing support mechanism is fixed to the top center of the base to provide non-contact vertical support force to counteract the weight of the test component. The ultrasonic standing wave stabilization mechanism is symmetrically arranged on both sides of the air-bearing support mechanism to maintain the horizontal stability of the test component. The adaptive clamping mechanism is installed on top of the ultrasonic standing wave stabilization mechanism to achieve non-contact limiting of test components of different sizes. The servo-driven error compensation mechanism is linked with the air-bearing support mechanism and the ultrasonic standing wave stabilization mechanism to correct microgravity simulation deviations in real time. The control system is electrically connected to each mechanism to control the coordinated operation of each mechanism. The test platform is set above the air-bearing support mechanism to place the spacecraft test component.

[0011] The air flotation support mechanism includes a cone-angle diffuser type air flotation nozzle; the top of the cone-angle diffuser type air flotation nozzle is evenly provided with several air outlets, the nozzle diffusion angle is 30°-60°, and the ball throat diameter ratio is 0.3-0.7.

[0012] The air flotation support mechanism also includes an air inlet pipe, a gas pressure regulating valve, and a gas filter; one end of the air inlet pipe is connected to the air flotation nozzle, and the other end is connected to an external high-pressure gas source; the gas pressure regulating valve and the gas filter are connected in series on the air inlet pipe; the air film thickness generated by the air flotation support mechanism is controlled within 0.05-0.1mm.

[0013] The ultrasonic standing wave stabilization mechanism includes an ultrasonic generator, an ultrasonic transducer, a reflecting end, and a standing wave field adjustment module; the ultrasonic transducer and the reflecting end are arranged opposite to each other, and the ultrasonic generator is electrically connected to the ultrasonic transducer to generate ultrasonic signals of 20-80kHz.

[0014] The standing wave field adjustment module is electrically connected to the ultrasonic generator and is used to adjust the frequency and amplitude of the ultrasonic signal; an ultrasonic standing wave field is formed between the ultrasonic transducer and the reflecting end, which maintains the horizontal stability of the test component through acoustic radiation pressure.

[0015] The adaptive clamping mechanism includes a telescopic link, an arc-shaped gripper, a pressure sensor, and a drive motor; the drive motor is connected to the telescopic link, the arc-shaped gripper is fixed to the end of the telescopic link, and a flexible polytetrafluoroethylene buffer layer is provided on the inner side of the gripper.

[0016] The pressure sensor is installed on the inside of the arc-shaped gripper to detect the gap between the gripper and the test component, ensuring that the gap is maintained at 0.1-0.2mm. This mechanism is suitable for test components with a size range of 50-500mm and a weight of 0.5-5kg.

[0017] The servo drive error compensation mechanism includes a servo motor, a ball screw, a displacement sensor, and a force sensor. The servo motor is connected to the ball screw and is linked with the air-bearing support mechanism and the ultrasonic standing wave stabilization mechanism. The displacement sensor is installed at the bottom of the test platform, and the force sensor is installed at the top of the air-bearing nozzle. The mechanism adjusts the air-bearing support force and the air-sound radiation pressure according to the deviation signal to control the microgravity simulation error within 4.0%.

[0018] The control system includes a PLC controller, a data acquisition module, a PID-fuzzy controller, and a human-machine interface. The data acquisition module is electrically connected to the displacement sensor, force sensor, and pressure sensor to collect signals from each sensor. The PID-fuzzy controller is connected to the data acquisition module to process deviation signals and output control commands. The PLC controller controls the coordinated operation of each mechanism, and the human-machine interface is used for parameter setting and data display.

[0019] The device achieves accurate microgravity simulation based on the following formula:

[0020] Target support formula: ,in The vertical support force is given by m, where m is the mass of the test component, and g is the acceleration due to gravity. The target is microgravity acceleration;

[0021] Error compensation control formula: Where u(t) is the control output quantity, , , These are the proportional, integral, and derivative coefficients, respectively, and e(t) is the real-time simulation deviation.

[0022] The microgravity simulation method using the above-mentioned device is characterized by comprising five steps: parameter setting, component positioning, composite suspension, error compensation, and test completion.

[0023] The composite suspension process includes: activating the air flotation support mechanism, where high-pressure gas is ejected through a cone-angle diffuser-type air flotation nozzle to form an air film that counteracts the gravity of the test component; and simultaneously activating the ultrasonic standing wave stabilization mechanism to form an ultrasonic standing wave field, which maintains the horizontal stability of the test component through acoustic radiation pressure.

[0024] The error compensation steps include: displacement sensors and force sensors acquiring the displacement deviation and support force deviation of the test component in real time; the controller processing the deviation signal and outputting control commands; and the servo motor driving the ball screw according to the commands to adjust the air intake pressure and aerodynamic radiation pressure of the air bearing support mechanism to correct the deviation.

[0025] Compared with existing technologies, the microgravity simulation device for ground testing of spacecraft components disclosed in this invention has the following significant advantages, completely solving the pain points of existing technologies and meeting the requirements of patent innovation, practicality, and novelty, as detailed below:

[0026] (1) High simulation accuracy: The air-float-ultrasonic standing wave composite suspension structure is adopted, combined with PID-fuzzy closed-loop error compensation control. The deviation is corrected in real time by formulas (4) and (5), and the microgravity simulation error is controlled within 4.0%, which is far better than the 13.9% of the existing technology, and the error fluctuation is ≤ ±0.5%. At the same time, the uniformity of the air film is optimized by the cone-angle diffusion nozzle (air film thickness fluctuation ≤ ±0.01mm), and the ultrasonic standing wave field ensures horizontal stability (offset ≤ 0.1mm). This effectively solves the problem of low simulation accuracy and large deviation fluctuation of the existing device, and meets the high-precision testing requirements of precision components of small spacecraft.

[0027] (2) Long simulation time: It abandons the short simulation defects of drop tower and electromagnetic catapult. Through composite suspension + closed loop control, it can realize stable microgravity simulation for several hours (up to 8 hours). It effectively solves the problem of short simulation time and inability to complete long-term static testing of existing devices. It is suitable for the comprehensive performance testing needs of precision components of small spacecraft (such as fatigue testing and stability testing). The experimental efficiency is increased to 10 minutes / time, which is much better than traditional devices (2-3 times / day).

[0028] (3) High versatility and no pollution: The adaptive clamping mechanism can be adapted to various small spacecraft precision parts with a size range of 50-500mm and a weight of 0.5-5kg. There is no need to change the clamps, which reduces the testing cost. At the same time, it adopts non-contact support and limiting method. The air-floating support has no physical contact. The adaptive clamping mechanism maintains a gap of 0.1-0.2mm, which effectively avoids wear and pollution on the surface of the test parts. It is especially suitable for testing easily damaged and easily polluted parts such as space metal 3D printed parts and precision sensors.

[0029] (4) Easy to operate and cost controllable: The control system integrates a visual human-machine interface, which makes parameter setting and data viewing convenient. The operation response time is ≤0.1s and no professional operators are required. The equipment is compact (base size ≤1.5m×1.5m), and the manufacturing cost is more than 70% lower than that of traditional drop towers. Moreover, it does not consume a lot of energy during the experiment, has low operating costs, can be adapted to batch component testing, and has a wide range of engineering application value.

[0030] (5) Strong anti-interference ability: The gas filter filters impurities and the gas pressure regulator stabilizes the pressure, reducing gas source fluctuation interference; the ultrasonic standing wave stabilization mechanism can resist slight airflow and vibration interference; the PID-fuzzy closed-loop control can correct deviations caused by external interference in real time, ensuring the stability of the simulation process, adapting to different laboratory environments, and requiring no special anti-interference facilities.

[0031] (6) It is suitable for ground microgravity environment simulation testing of precision components of small spacecraft (such as micro sensors, small structural parts, propulsion system parts, and space metal 3D printed parts). It can realize long-term, high-precision, non-contact microgravity simulation, meet the ground verification requirements of the on-orbit working performance (structural reliability, functional stability, working accuracy) of spacecraft components, and is especially suitable for batch testing scenarios of small spacecraft components in areas with scarce expert medical resources. Attached Figure Description

[0032] Figure 1 : A schematic diagram of the overall structure of the microgravity simulation device for ground testing of spacecraft components provided in this embodiment of the invention;

[0033] Figure 2 : A schematic diagram of the air-float support mechanism provided in an embodiment of the present invention;

[0034] Figure 3 : A schematic diagram illustrating the working principle of the ultrasonic standing wave stabilization mechanism provided in this embodiment of the invention;

[0035] Figure 4 : A schematic diagram of the adaptive clamping mechanism structure provided in this embodiment of the invention;

[0036] Figure 5 The control system principle block diagram provided in the embodiments of the present invention;

[0037] Figure 6 The following is a flowchart of the working process provided in the embodiments of the present invention;

[0038] Figure 7 : A schematic diagram of the suspended state of the test component provided in this embodiment of the invention.

[0039] Explanation of reference numerals in the attached drawings: 1-Base, 2-Air flotation support mechanism, 21-Conical angle diffuser type air flotation nozzle, 22-Inlet pipe, 23-Gas pressure regulating valve, 24-Gas filter, 25-Outlet, 3-Ultrasonic standing wave stabilization mechanism, 31-Ultrasonic generator, 32-Ultrasonic transducer, 33-Reflecting end, 34-Standing wave field adjustment module, 4-Adaptive clamping mechanism, 41-Telescopic linkage, 42-Arc-shaped gripper, 43-Pressure sensor, 44-Drive motor, 45-Flexible buffer layer, 5-Servo drive error compensation mechanism, 51-Servo motor, 52-Ball screw, 53-Displacement sensor, 54-Force sensor, 6-Control system, 61-PLC controller, 62-Data acquisition module, 63-PID fuzzy controller, 64-Human machine interface, 7-Test platform, 8-Test component. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] A microgravity simulation device for ground testing of spacecraft components includes a base 1, an air-bearing support mechanism 2, an ultrasonic standing wave stabilization mechanism 3, an adaptive clamping mechanism 4, a servo-driven error compensation mechanism 5, a control system 6, and a test platform 7. The air-bearing support mechanism 2 is fixed to the top center of the base 1 to provide non-contact vertical support force to counteract the gravity of the test component 8. The ultrasonic standing wave stabilization mechanism 3 is symmetrically arranged on both sides of the air-bearing support mechanism 2 to maintain the horizontal stability of the test component 8 and prevent horizontal deviation. The adaptive clamping mechanism 4 is installed on top of the ultrasonic standing wave stabilization mechanism 3 to adapt to test components 8 of different sizes and weights, achieving non-contact limiting. The servo-driven error compensation mechanism 5 is connected to the air-bearing support mechanism 2 and the ultrasonic standing wave stabilization mechanism 3 to correct microgravity simulation deviations in real time. The control system 6 is electrically connected to the air-bearing support mechanism 2, the ultrasonic standing wave stabilization mechanism 3, the adaptive clamping mechanism 4, and the servo-driven error compensation mechanism 5 to control the coordinated operation of each mechanism. The test platform 7 is located above the air-bearing support mechanism 2 and is used to place the spacecraft test component 8.

[0042] 1. Specific structure of each organization

[0043] (1) Air flotation support mechanism 2: including a cone-angle diffusion type air flotation nozzle 21, an air inlet pipe 22, a gas pressure regulating valve 23, and a gas filter 24; the cone-angle diffusion type air flotation nozzle 21 is fixed to the top of the base 1, the nozzle diffusion angle is 30°-60° (preferably 45°), the ball-throat diameter ratio is 0.3-0.7 (preferably 0.5), and a number of air outlets 25 are evenly opened on the top (the number of air outlets is 12-24, preferably 18), which are used to spray high-pressure gas to form a uniform gas film; the air inlet pipe 22 One end is connected to the air flotation nozzle 21, and the other end is connected to an external high-pressure air source (air source pressure is 0.3-0.8MPa). The gas pressure regulating valve 23 and the gas filter 24 are connected in series on the air inlet pipe 22, respectively used to stabilize the air inlet pressure (pressure fluctuation ≤ ±0.02MPa) and filter gas impurities (filtration accuracy ≤ 0.1μm), to avoid gas film fluctuation and impurity contamination of the test component 8. The gas film thickness is controlled at 0.05-0.1mm (preferably 0.08mm) to ensure vertical support stability.

[0044] (2) Ultrasonic standing wave stabilization mechanism 3: includes an ultrasonic generator 31, an ultrasonic transducer 32, a reflector 33, and a standing wave field adjustment module 34; the ultrasonic transducer 32 is symmetrically fixed on the base 1 on both sides of the air-bearing support mechanism 2 (the number of transducers is 2-4, preferably 2), the ultrasonic generator 31 is electrically connected to the ultrasonic transducer 32, and is used to generate an ultrasonic signal of 20-80kHz (preferably 50kHz); the reflector 33 is arranged opposite to the ultrasonic transducer 32 and fixed to the bottom of the adaptive clamping mechanism 4, forming an ultrasonic standing wave field between it and the ultrasonic transducer 32, and maintaining the horizontal stability of the test component 8 through acoustic radiation pressure; the standing wave field adjustment module 34 is electrically connected to the ultrasonic generator 31, and is used to adjust the frequency and amplitude of the ultrasonic signal (amplitude adjustment range 0-50V), adapt to test components 8 of different weights, and ensure horizontal stability without deviation (deviation ≤0.1mm).

[0045] (3) Adaptive clamping mechanism 4: including telescopic link 41, arc-shaped gripper 42, pressure sensor 43 and drive motor 44; the telescopic link 41 is symmetrically arranged on the top of the ultrasonic standing wave stabilization mechanism 3 (the number of links is 2-4, preferably 2), and the drive motor 44 is connected to the telescopic link 41 to drive the telescopic link 41 to extend and retract (extension range 0-300mm); the arc-shaped gripper 42 is fixed to the end of the telescopic link 41, and a flexible buffer layer 45 (made of polytetrafluoroethylene material, thickness 0.5-1mm) is provided on the inner side of the gripper to avoid contact wear; the pressure sensor 43 is installed on the inner side of the arc-shaped gripper 42 to detect the distance between the gripper and the test component 8, ensuring that the gap between the gripper and the test component 8 is 0.1-0.2mm, realizing non-contact limiting, and adapting to small spacecraft components with a size range of 50-500mm and a weight of 0.5-5kg.

[0046] (4) Servo drive error compensation mechanism 5: including servo motor 51, ball screw 52, ​​displacement sensor 53 and force sensor 54; the servo motor 51 is fixed on one side of the base 1 (a servo motor with a rated power of 0.5-2kW is selected), the ball screw 52 is connected to the output end of the servo motor 51 and is linked with the air-bearing support mechanism 2 and the ultrasonic standing wave stabilization mechanism 3; the displacement sensor 53 is installed at the bottom of the test platform 7 (measurement accuracy ≤0.01mm) and is used to detect the displacement deviation of the test component 8; the force sensor 54 is installed at the top of the air-bearing nozzle 21 (measurement accuracy ≤0.01N) and is used to detect the deviation of the air-bearing support force; the servo motor 51 drives the ball screw 52 to move according to the deviation signal, adjusts the air-bearing support force and the air-sound radiation pressure, realizes real-time error compensation, controls the microgravity simulation error within 4.0%, and the error fluctuation ≤±0.5%.

[0047] (5) Control system 6: including PLC controller 61, data acquisition module 62, PID-fuzzy controller 63 and human-machine interface 64; the data acquisition module 62 is electrically connected to displacement sensor 53, force sensor 54 and pressure sensor 43, and is used to acquire signals from each sensor (acquisition frequency is 100-500Hz, preferably 300Hz); the PID-fuzzy controller 63 is connected to data acquisition module 62 and is used to process the acquired deviation signals and output control commands; the PLC controller 61 is electrically connected to PID-fuzzy controller 63 and is used to control the air-float support mechanism 2, ultrasonic standing wave stabilization mechanism 3, adaptive clamping mechanism 4 and servo drive error compensation mechanism 5 to work together; the human-machine interface 64 is used for parameter setting (such as microgravity coefficient, test time) and data display (such as simulation error, support force), realizing visual operation, and the operation response time is ≤0.1s.

[0048] 2. Core Formula Design

[0049] This invention achieves precise control and parameter optimization in microgravity simulation through the following formulas, ensuring simulation accuracy and stability. The formulas work together to form a complete control system:

[0050] (1) Formula for target support force in microgravity simulation:

[0051]

[0052] In the formula: The vertical target support force (N) required for the air-bearing support mechanism 2; m is the mass of the test component 8 (kg); g is the acceleration due to gravity (m / s²), taken as 9.8 m / s². The target microgravity acceleration (m / s²) is given. , where k is the microgravity coefficient (0 < k < 1), which can be adjusted according to test requirements (for example, k = 0.165 when simulating lunar gravity, k = 0.377 when simulating Martian gravity, and k ≤ 0.001 when simulating microgravity in low Earth orbit), to achieve the microgravity simulation requirements under multiple working conditions and adapt to the test scenarios of different spacecraft components.

[0053] (2) Calculation formula for aerostatic support force (based on the parameters of the conical angle diffusion nozzle):

[0054]

[0055] In the formula: is the actual output support force of the aerostatic support mechanism 2 (N); ρ is the density of the high-pressure gas (kg / m³), and when dry air is selected, ρ = 1.29 kg / m³; v is the gas ejection velocity (m / s); A is the total area of the air outlet 25 of the aerostatic nozzle 21 (m²); θ is the nozzle diffusion angle (°); η is the air film efficiency coefficient (0.85 - 0.95), which is adjusted according to the nozzle ball throat diameter ratio. The larger the ball throat diameter ratio, the smaller η. By optimizing the parameters, ensure , to achieve precise cancellation of gravity in the vertical direction and lay the foundation for microgravity simulation.

[0056] (3) Calculation formula for the maximum sound pressure of ultrasonic standing waves (to optimize the horizontal stability):

[0057]

[0058] In the formula: is the maximum sound pressure of the ultrasonic standing wave field (Pa); c is the speed of sound in the gas (m / s), taking 340 m / s; is the sound intensity output by the ultrasonic transducer 32 (W / m²); R is the reflection coefficient of the reflection end 33 (0.9 - 0.98); by adjusting and R, make meet the horizontal stability requirements, avoid the horizontal offset of the test component 8, ensure that the test component is in a stable suspension state, and cooperate with the aerostatic support mechanism 2 to achieve three-dimensional stable suspension.

[0059] (4) PID-fuzzy compensation control formula (to correct deviations in real time):

[0060]

[0061] In the formula: u(t) is the control output of the servo drive error compensation mechanism (V); is the proportional coefficient, is the integral coefficient, is the differential coefficient, which is dynamically adjusted by the fuzzy controller according to the deviation e(t) (adjustment range 0 - 10); e(t) is the real-time microgravity simulation deviation (e(t) = This formula enables real-time correction of deviations, keeping the microgravity simulation error within 4.0%, which is better than the 13.9% of existing technologies, ensuring stable simulation accuracy.

[0062] (5) Formula for calculating microgravity simulation error (quantifying simulation accuracy):

[0063]

[0064] Where: δ is the microgravity simulation error (%); The actual microgravity acceleration (m / s²) is required; δ≤4.0% is required to ensure that the accuracy of the microgravity simulation meets the testing requirements of precision components of small spacecraft, and the error fluctuation is ≤±0.5% to achieve long-term stable simulation and provide a reliable environment for component performance testing.

[0065] (3) Work process

[0066] The microgravity simulation device of the present invention operates as follows, with each step seamlessly connected, enabling automated testing and simple operation:

[0067] Step 1: Parameter setting. Input the test parameters through the human-machine interface 64, including the mass m of the test component 8, the target microgravity coefficient k, and the test time t. The PLC controller 61 calculates the vertical target support force according to the input parameters using formula (1). The initial operating parameters (gas ejection velocity v, ultrasonic signal frequency, and sound intensity) of the air-bearing support mechanism 2 and the ultrasonic standing wave stabilizing mechanism 3 are calculated using formulas (2) and (3). ), complete device initialization.

[0068] Step 2: Component positioning. Place the spacecraft test component on the test platform 7, activate the adaptive clamping mechanism 4, drive the motor 44 to extend and retract the telescopic connecting rod 41, and the pressure sensor 43 detects the distance between the gripper and the test component 8 in real time. Adjust the distance to a non-contact gap of 0.1-0.2mm to complete the positioning and fixation of the test component 8, avoiding contact contamination and wear, and adapting to the quick clamping of components of different sizes.

[0069] Step 3: Composite Suspension. Activate the air flotation support mechanism 2. External high-pressure gas, after being filtered by the gas filter 24 and stabilized by the gas pressure regulating valve 23, is ejected through the cone-angle diffuser-type air flotation nozzle 21, forming a uniform air film. The air flotation support force... The test component 8 is partially counteracted by gravity, thus achieving a preliminary microgravity simulation. Simultaneously, the ultrasonic standing wave stabilization mechanism 3 is activated. The ultrasonic generator 31 generates an ultrasonic signal of a set frequency, which is converted into a sound wave by the ultrasonic transducer 32. This sound wave forms an ultrasonic standing wave field with the reflector 33, maintaining the horizontal stability of the test component 8 through acoustic radiation pressure and preventing horizontal displacement, thus achieving three-dimensional stable suspension.

[0070] Step 4: Error Compensation. During the test, displacement sensor 53 and force sensor 54 collect the displacement deviation and support force deviation of test component 8 in real time. Data acquisition module 62 transmits the deviation signal to PID-fuzzy controller 63. The controller processes the deviation signal through formula (4) and outputs control commands to servo drive error compensation mechanism 5. Servo motor 51 drives ball screw 52 to move according to control commands, adjusting the air intake pressure of air-bearing support mechanism 2 (changing the gas ejection speed v) and air-sound radiation pressure (changing the ultrasonic intensity). Dynamically correct support force deviation to ensure The simulation error δ is monitored in real time by formula (5) to ensure that δ≤4.0% and achieve long-term stable microgravity simulation.

[0071] Step 5: Test complete. After the test is completed, turn off the ultrasonic standing wave stabilization mechanism 3, the air buoyancy support mechanism 2, and the servo drive error compensation mechanism 5 in sequence. Adjust the adaptive clamping mechanism 4 to loosen it, and take out the test component 8 to complete one microgravity test. The test data (simulation error, support force, test time, etc.) can be viewed through the human-machine interface 64, and the data can be saved and exported for subsequent data analysis and report writing.

[0072] The application principle of the present invention will be described in detail below with reference to the accompanying drawings. This embodiment takes the near-Earth orbit microgravity simulation test (microgravity coefficient k=0.001) of a small spacecraft micro-sensor (mass 0.8kg, size 80mm×60mm×50mm) as an example to verify the effectiveness of the present invention.

[0073] like Figure 6 As shown in the figure, the microgravity simulation device for ground testing of spacecraft components provided in this embodiment of the invention includes the following steps in its operation:

[0074] Step 1: Parameter setting. Input the test parameters through the human-machine interface 64: mass of test component 8 m = 0.8 kg, target microgravity coefficient k = 0.001, test time t = 60 minutes; PLC controller 61, based on the input parameters, uses formula (1) to... Calculate the target support force ,in Substituting into ; through formula (2) Calculate the gas ejection velocity v, set the diffusion angle of nozzle 21 θ=45°, the ball-throat diameter ratio 0.5, the gas film efficiency coefficient η=0.9, the total area of ​​nozzle outlet 25 A=0.0002m², and the dry air density ρ=1.29kg / m³, substituting these values, we get v≈78.2m / s; using formula (3) Calculating ultrasonic intensity Given a reflection coefficient R=0.95 at reflector 33 and a sound velocity c=340m / s, what is the maximum sound pressure level? Substituting into Set the ultrasonic signal frequency to 50kHz and complete the device initialization.

[0075] Step 2: Component positioning. Place the miniature spacecraft sensor on the test platform 7, activate the adaptive clamping mechanism 4, drive the motor 44 to extend and retract the telescopic link 41, and the pressure sensor 43 detects the distance between the arc-shaped gripper 42 and the sensor in real time, adjusting it to a non-contact gap of 0.15mm to complete the positioning and fixing of the sensor, avoiding contact contamination of the precision components on the sensor surface.

[0076] Step 3: Composite Suspension. Activate the air flotation support mechanism 2. External high-pressure air (0.5 MPa) is filtered by gas filter 24 (0.1 μm filtration accuracy) and stabilized by gas pressure regulator 23 (pressure fluctuation ±0.02 MPa). It is then ejected through cone-angle diffuser-type air flotation nozzle 21, forming a uniform air film with a thickness of 0.08 mm. The air flotation support force... This counteracts most of the sensor's gravity, initially achieving microgravity simulation. Simultaneously, the ultrasonic standing wave stabilization mechanism 3 is activated. The ultrasonic generator 31 produces a 50kHz ultrasonic signal, which is converted into sound waves by the ultrasonic transducer 32. This forms an ultrasonic standing wave field with the reflecting end 33, maintaining the sensor's horizontal stability through acoustic radiation pressure. The horizontal offset is ≤0.1mm, achieving three-dimensional stable levitation. Figure 7 As shown.

[0077] Step 4: Error Compensation. During the test, displacement sensor 53 (measurement accuracy 0.01mm) and force sensor 54 (measurement accuracy 0.01N) collect the displacement deviation and support force deviation of the sensors in real time. Data acquisition module 62 collects the signals of each sensor at a frequency of 300Hz and transmits them to PID-fuzzy controller 63; the controller uses formula (4) The deviation signal is processed, and the proportional coefficient is dynamically adjusted. Integral coefficient Differential coefficients The control command is output to the servo drive error compensation mechanism 5; the servo motor 51 (rated power 1kW) drives the ball screw 52 to move according to the control command, adjusting the air intake pressure of the air bearing support mechanism 2 (changing the gas ejection speed v) and the air acoustic radiation pressure (changing the ultrasonic intensity). The support force deviation is dynamically corrected using formula (5). The simulation error δ is monitored in real time. During the test, δ is stable between 2.8% and 3.5%, and the error fluctuation is ≤ ±0.3%, which meets the test accuracy requirements.

[0078] Step 5: Test complete. After the 60-minute test, the control system 6 sequentially shuts down the ultrasonic standing wave stabilization mechanism 3, the air-bearing support mechanism 2, and the servo drive error compensation mechanism 5. The telescopic linkage 41 of the adaptive clamping mechanism 4 is retracted, the sensor is released, and the test component 8 is removed. The test data is viewed and saved through the human-machine interface 64: average simulation error 3.2%, maximum offset 0.08mm, test time 60 minutes, support force fluctuation ±0.02N. The data is exported for subsequent performance analysis.

Claims

1. A microgravity simulation device for ground testing of spacecraft components, characterized in that, The system includes a base, an air-bearing support mechanism, an ultrasonic standing wave stabilization mechanism, an adaptive clamping mechanism, a servo-driven error compensation mechanism, a control system, and a test platform. The air-bearing support mechanism is fixed to the top center of the base and provides non-contact vertical support to counteract the weight of the test component. The ultrasonic standing wave stabilization mechanism is symmetrically arranged on both sides of the air-bearing support mechanism to maintain the horizontal stability of the test component. The adaptive clamping mechanism is installed on top of the ultrasonic standing wave stabilization mechanism to achieve non-contact limiting of test components of different sizes. The servo-driven error compensation mechanism is linked with the air-bearing support mechanism and the ultrasonic standing wave stabilization mechanism to correct microgravity simulation deviations in real time. The control system is electrically connected to each mechanism to control the coordinated operation of each mechanism. The test platform is located above the air-bearing support mechanism and is used to place spacecraft test components.

2. The microgravity simulation device for ground testing of spacecraft components according to claim 1, characterized in that, The air flotation support mechanism includes a cone-angle diffusion type air flotation nozzle; the top of the cone-angle diffusion type air flotation nozzle is evenly provided with several air outlets, the nozzle diffusion angle is 30°-60°, and the ball-throat diameter ratio is 0.3-0.

7.

3. The microgravity simulation device for ground testing of spacecraft components according to claim 2, characterized in that, The air flotation support mechanism also includes an air inlet pipe, a gas pressure regulating valve, and a gas filter; one end of the air inlet pipe is connected to the air flotation nozzle, and the other end is connected to an external high-pressure gas source; the gas pressure regulating valve and the gas filter are connected in series on the air inlet pipe; the thickness of the air film generated by the air flotation support mechanism is controlled between 0.05-0.1 mm.

4. The microgravity simulation device for ground testing of spacecraft components according to claim 1, characterized in that, The ultrasonic standing wave stabilization mechanism includes an ultrasonic generator, an ultrasonic transducer, a reflecting end, and a standing wave field adjustment module; the ultrasonic transducer and the reflecting end are arranged opposite to each other, and the ultrasonic generator is electrically connected to the ultrasonic transducer to generate ultrasonic signals of 20-80kHz.

5. The microgravity simulation device for ground testing of spacecraft components according to claim 4, characterized in that, The standing wave field adjustment module is electrically connected to the ultrasonic generator and is used to adjust the frequency and amplitude of the ultrasonic signal; an ultrasonic standing wave field is formed between the ultrasonic transducer and the reflecting end, and the test component is kept horizontally stable by acoustic radiation pressure.

6. The microgravity simulation device for ground testing of spacecraft components according to claim 1, characterized in that, The adaptive clamping mechanism includes a telescopic link, an arc-shaped gripper, a pressure sensor, and a drive motor; the drive motor is connected to the telescopic link, the arc-shaped gripper is fixed to the end of the telescopic link, and a polytetrafluoroethylene flexible buffer layer is provided on the inner side of the gripper.

7. The microgravity simulation device for ground testing of spacecraft components according to claim 6, characterized in that, The pressure sensor is installed on the inside of the arc-shaped gripper to detect the gap between the gripper and the test component, ensuring that the gap is maintained at 0.1-0.2mm; the mechanism is suitable for test components with a size range of 50-500mm and a weight of 0.5-5kg.

8. The microgravity simulation device for ground testing of spacecraft components according to claim 1, characterized in that, The servo drive error compensation mechanism includes a servo motor, a ball screw, a displacement sensor, and a force sensor. The servo motor is connected to the ball screw and is linked with the air-bearing support mechanism and the ultrasonic standing wave stabilization mechanism. The displacement sensor is installed at the bottom of the test platform, and the force sensor is installed at the top of the air-bearing nozzle. The mechanism adjusts the air-bearing support force and the air-sound radiation pressure according to the deviation signal to control the microgravity simulation error within 4.0%.

9. The microgravity simulation device for ground testing of spacecraft components according to claim 1, characterized in that, The control system includes a PLC controller, a data acquisition module, a PID-fuzzy controller, and a human-machine interface. The data acquisition module is electrically connected to a displacement sensor, a force sensor, and a pressure sensor to acquire signals from each sensor. The PID-fuzzy controller is connected to the data acquisition module to process deviation signals and output control commands. The PLC controller controls the coordinated operation of each mechanism, and the human-machine interface is used for parameter setting and data display.

10. The microgravity simulation device for ground testing of spacecraft components according to any one of claims 1-9, characterized in that, The device achieves accurate microgravity simulation based on the following formula: Target support formula: ,in The vertical support force is given by m, where m is the mass of the test component, and g is the acceleration due to gravity. The target is microgravity acceleration; Error compensation control formula: Where u(t) is the control output quantity, , , These are the proportional, integral, and derivative coefficients, respectively, and e(t) is the real-time simulation deviation.

11. A microgravity simulation method based on the device according to any one of claims 1-10, characterized in that, The method includes five steps: parameter setting, component positioning, composite suspension, error compensation, and test completion.

12. The microgravity simulation method according to claim 11, characterized in that, The composite suspension step includes: activating the air flotation support mechanism, where high-pressure gas is ejected through a cone-angle diffuser air flotation nozzle to form an air film that counteracts the gravity of the test component; and simultaneously activating the ultrasonic standing wave stabilization mechanism to form an ultrasonic standing wave field, which maintains the horizontal stability of the test component through acoustic radiation pressure.

13. The microgravity simulation method according to claim 11, characterized in that, The error compensation steps include: displacement sensors and force sensors acquiring displacement deviation and support force deviation of the test component in real time; controller processing the deviation signal and outputting control commands; servo motor driving ball screw according to the commands to adjust air intake pressure and aerodynamic radiation pressure of air bearing support mechanism to correct the deviation.

Images