An experimental device for simulating active control of satellite platform vibration and its use method

Abstract

The present invention discloses an experimental device for simulating active control of satellite platform vibration and a method for use. A high-strength, low-elasticity rope is used to suspend a cubic satellite model on a rigid frame to achieve horizontal gravity unloading. The exciter is fixed horizontally on the rigid frame and connected to the cubic satellite model through a dual-mode connecting rod. Flexible beams are installed in the centers of both sides of the model, and resistance strain gauges and PVDF films are used as beam vibration sensors. Piezoelectric fiber composite materials are bonded to the surface as vibration control elements. A laser displacement meter is installed on the side of the cubic satellite opposite to the exciter, and the laser displacement meter is fixed to the rigid frame. During operation, the exciter vibrates the cubic satellite model through the connecting rod, driving the flexible beams on both sides to vibrate, and the sensors at the roots of the flexible beams on both sides will have output signals. After the real-time controller collects the sensor output signals, it realizes satellite platform vibration control and flexible beam vibration control through a control algorithm. The present invention has good application prospects in vibration-related technology research and experimental teaching.

Description

Technical Field

[0001] The present invention belongs to the technical field of active control of structural vibrations, and specifically relates to an experimental device for active control of simulated satellite platform vibrations and a method for using the device. The device can be used in experimental technology research, experimental teaching, and other aspects. Background Art

[0002] The vibration of mechanical structures is a common physical phenomenon in life. Large-scale flexible structures are often installed on satellite platforms, such as solar panels, large satellite antennas, space robotic arms, etc., and the size of flexible structures is getting larger and larger. Flexible structures are easily affected by external environmental factors or loads such as the satellite's momentum wheel, which can easily cause vibrations. In particular, resonance occurs when the frequency is close to the natural frequency, and the resonance at this time may affect the stability of the platform or the stability of the load on the platform. Building a simulation of the in-orbit working state of a satellite platform on the ground is of great significance to the dynamic research and vibration suppression of the spacecraft. At present, there is a lack of experimental equipment in China that can study the vibration characteristics of spacecraft and vibration control technology under the simulated weightlessness of the satellite platform. Summary of the Invention

[0003] To address the current lack of experimental equipment for studying spacecraft vibration characteristics and vibration control technologies in a simulated satellite platform weightlessness in China, the present invention aims to provide a multi-sensor active structural vibration control experimental device and its use method in a laboratory simulated satellite platform weightlessness. The device has the advantages of simple implementation, rich measurement methods, and intuitive and diverse results display.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An experimental device for simulating active control of satellite platform vibration includes a rigid frame 1, a vibration exciter 2, a connecting rod 3, a high-strength low-deformation rope 4, a cubic satellite model 5, a first flexible beam 6, a second flexible beam 7, a laser displacement meter 8, an accelerometer 9, a power amplifier 10, and a real-time controller 11;

[0006] The length direction of the rigid frame 1, i.e., the X-axis direction, is the working direction of the device. An exciter 2 is installed on one side of the length direction, i.e., the X-axis direction. The exciter 2 is connected to the cubic satellite model 5 via a connecting rod 3. The central axis of the exciter 2 coincides with the center line of the cubic satellite model 5. The cubic satellite model 5 is suspended on the rigid frame 1 by multiple high-strength, low-deformation ropes 4. The multiple high-strength, low-deformation ropes 4 are of equal length, achieving horizontal movement in the working direction, motion constraint in the width direction, achieving satellite gravity unloading, and a small range of free movement in the working direction, which can simulate the satellite's on-orbit motion state.

[0007] The CubeSat model 5 is a frame-type structure, with a first flexible beam 6 and a second flexible beam 7 installed at the center of both side surfaces in the width direction, i.e., along the Y-axis, to form a cantilever beam structure. An accelerometer 9 is installed on the other side of the CubeSat model 5 corresponding to the vibrator 2. A laser displacement meter measuring point is also provided on a horizontal line adjacent to the accelerometer 9. The laser displacement meter 8 is fixed to the rigid frame 1, and the measurement signals of the laser displacement meter 8 and the accelerometer 9 are output to a real-time controller 11.

[0008] The connecting rod 3 uses a piezoelectric stack as a basic driving element and is a functional device that can output force and displacement along the axial direction. It has two working modes. When the connecting rod 3 is not powered and does not actively work, and only serves as a mechanical connection between the vibrator 2 and the cubic satellite model 5, the vibrator 2 drives the cubic satellite model 5 and the first flexible beam 6 and the second flexible beam 7 of the load installed on the cubic satellite model to vibrate. The working voltage of the piezoelectric stack in the connecting rod is a positive voltage. When powered on and not controlled, the piezoelectric stack in the connector 3 works at the middle value of the maximum driving voltage. The increase in voltage on this basis will cause the connecting rod to extend and output thrust. Reducing the voltage on the basis of the middle value of the maximum driving voltage will cause the connecting rod to contract and output tension relative to the powered and uncontrolled state. Therefore, when the connecting rod 3 is powered on and working, as a device for isolating the cubic satellite model, it can be combined with an accelerometer 8 or a laser displacement meter 9 and a real-time controller 11 to achieve vibration isolation between the vibrator 2 and the cubic satellite model 5, thereby achieving stable control of the cubic satellite platform.

[0009] The first flexible beam 6 and the second flexible beam 7 have the same structure and are made of the same material. Two PVDF piezoelectric films are attached to the first flexible beam 6 as vibration measurement sensors. At the same time, two piezoelectric fiber composite materials are attached opposite the two PVDF piezoelectric films. The piezoelectric fiber composite material is a thin film device. After being attached to the flexible beam, it uses the inverse piezoelectric effect to output a torque acting on the first flexible beam, thereby affecting the vibration state of the first flexible beam.

[0010] Eight resistance strain gauges are attached to the second flexible beam 7 , and four resistance strain gauges form a group to form a strain full bridge for measuring the deformation of the middle part of the second flexible beam 7 ;

[0011] The second flexible beam 7 is bonded with a piezoelectric fiber composite material near the two strain full bridges. The two piezoelectric fiber composite materials are independently connected to the power amplifier 10. The inverse piezoelectric effect is used to output a torque acting on the second flexible beam, thereby affecting the vibration state of the second flexible beam.

[0012] The CubeSat model 5 integrates a strain signal processing module and a charge signal processing module. The strain bridge signal output on the second flexible beam 7 is introduced into the strain signal processing module of the CubeSat model 5, and after amplification, the strain signal is output to the input end of the real-time controller 11. The charge signal output by the PVDF piezoelectric film on the first flexible beam 6 is introduced into the charge signal processing module of the CubeSat model 5, and after amplification, the voltage signal is output to the input end of the real-time controller 11.

[0013] The power amplifier 10 has multiple input and output channels, the input end is connected to the output end of the real-time controller 11, and the output end of the power amplifier 10 is connected to the piezoelectric fiber composite material of the first flexible beam 6 and the second flexible beam 7 and the connecting rod 3;

[0014] An analog-to-digital conversion module is integrated on the real-time controller 11 to collect the processed signals generated by the strain bridge and the signals generated by the PVDF piezoelectric film, perform calculations on the real-time controller 11, convert the calculated digital quantities into digital-to-analog quantities, and output an analog voltage for control. The voltage amplified by the power amplifier acts on the piezoelectric fiber composite materials of the first flexible beam 6 and the second flexible beam 7, so that the flexible beams are subjected to a torque, causing the flexible beams to produce a deformation opposite to the current vibration state, thereby realizing vibration control of the flexible beams.

[0015] Preferably, the real-time controller 11 implements the following vibration isolation control process between the vibrator 2 and the CubeSat model 5: When the vibrator 2 vibrates the CubeSat model 5 through the conduction of the connecting rod 3, the accelerometer 9 and the laser displacement meter 8 can measure the vibration of the CubeSat model 5 along the X direction. After obtaining the measurement signal from the accelerometer 9 or the laser displacement meter 8, the real-time controller 11 calculates and outputs a control signal that acts on the connecting rod 3 through the power amplifier 10, causing the connecting rod 3 to output a displacement opposite to the vibration direction of the CubeSat model 5, thereby reducing the vibration of the CubeSat model 5 and approaching zero, thereby achieving vibration isolation between the vibrator 2 and the CubeSat model 5.

[0016] Preferably, the plane where the first flexible beam 6 and the second flexible beam 7 are located is parallel to the vertical plane, that is, parallel to the YOZ plane.

[0017] Preferably, a first PVDF piezoelectric film 6.1 is pasted on the middle part of the first flexible beam 6, and a second PVDF piezoelectric film 6.2 is pasted on the root as a vibration measurement sensor, and at the same time, a first piezoelectric fiber composite material 6.3 and a second piezoelectric fiber composite material 6.4 of thin film materials are pasted on positions opposite to the first PVDF piezoelectric film 6.1 and the second PVDF piezoelectric film 6.2; the piezoelectric fiber composite material is a thin film type device, which can output a torque acting on the first flexible beam by utilizing the inverse piezoelectric effect after being bonded to the flexible beam, thereby affecting the vibration state of the first flexible beam.

[0018] Preferably, two resistance strain gauges are bonded to each surface of the root of the second flexible beam 7, with a total of four resistance strain gauges on the two surfaces, and the four resistance strain gauges have the same resistance value, namely the first resistance strain gauge 7.1, the second resistance strain gauge 7.2, the third resistance strain gauge 7.3, and the fourth resistance strain gauge 7.4. The four resistance strain gauges form a strain full bridge for measuring the deformation of the root of the second flexible beam 7. Two resistance strain gauges are bonded to each surface of the middle part of the second flexible beam 7, with a total of four resistance strain gauges on the two surfaces, and the four resistance strain gauges have the same resistance value, namely the fifth resistance strain gauge 7.5, the sixth resistance strain gauge 7.6, the seventh resistance strain gauge 7.7, and the eighth resistance strain gauge 7.8. The four resistance strain gauges form a strain full bridge for measuring the deformation of the middle part of the second flexible beam 7.

[0019] Preferably, after the resistance strain gauge is bonded to the second flexible beam 7, a third piezoelectric fiber composite material 7.9 is bonded to the side close to the root, and a fourth piezoelectric fiber composite material 7.10 is bonded to the middle part. The two piezoelectric fiber composite materials are independently connected to the power amplifier 10, and the inverse piezoelectric effect is used to output a torque acting on the second flexible beam, thereby affecting the vibration state of the second flexible beam.

[0020] The method for using the active control experimental device for simulating satellite platform vibration is as follows:

[0021] First, the vibrator 2 operates in a sweep frequency mode, so that the first flexible beam 6 and the second flexible beam 7 on the cubic satellite model enter a sweep frequency vibration state; the real-time controller 11 collects and processes the output signals of the two PVDF piezoelectric films on the first flexible beam 6 and the output signals of the two strain bridges on the second flexible beam 7 to obtain the first two natural frequencies of the measured flexible beams; or the strain signal processed by the strain signal processing module and the charge signal processed by the charge signal processing module are output to an external measuring device to measure the first two natural frequencies of the first flexible beam 6 and the second flexible beam 7; a certain frequency point in the first two orders is selected for excitation to put the flexible beams in a certain order resonance state; when one of the two flexible beams is controlled and the other is not controlled and only monitored, the motion state of the two flexible beams during vibration control is compared to intuitively evaluate the control effect;

[0022] The connecting rod 3 can work in active and passive modes. In the passive mode, no power is supplied and only vibration is transmitted. In the active mode, the connecting rod 3 outputs force and displacement, and the accelerometer 9 or laser displacement meter 8 measures the vibration of the cubic satellite model. When the flexible beam vibration is actively controlled, the cubic satellite model is in a vibrating state, and the accelerometer 9 or laser displacement meter 8 monitors the vibration of the cubic satellite model. The real-time controller runs a closed-loop control algorithm to calculate the control quantity, and the control digital quantity outputs an analog voltage signal after passing through the digital-to-analog conversion circuit. The analog voltage signal is amplified by the power amplifier 10 and output to the connecting rod 3. Under the control of the driving voltage, the connecting rod 3 outputs a displacement opposite to the current vibration direction, so that the vibration of the cubic satellite model platform is suppressed, thereby realizing active isolation of the platform vibration.

[0023] The present invention uses a cubic satellite model with a flexible structure suspended on a rigid frame to gravity unload the cubic satellite model in the working direction, simulating the satellite's in-orbit state. The detachable flexible structure can be used with different vibration sensors, and the flexible beam structure can be replaced with different sizes and materials to achieve switching of vibration control for different objects and sensing methods. The connecting rod can operate in active or passive mode, and active vibration control of the flexible beam can be carried out simultaneously. The active vibration isolation experimental test content between the cubic satellite model platform and the exciter is rich and diverse. The present invention has the following advantages:

[0024] 1. By suspending the cubic satellite model and installing the flexible beam vertically, gravity unloading can be effectively achieved in a low-cost manner.

[0025] 2. The symmetrical arrangement of flexible beams can effectively reduce the impact of eccentric mass on gravity unloading.

[0026] 3. A single connecting rod has two operating modes. In active mode, it can be used to conduct experimental research on vibration isolation technology in the weightless state of satellite platforms. In passive mode, it can be used as a vibration transmission rod to carry out research on active vibration control of flexible beams.

[0027] 4. By integrating a variety of vibration test sensors, the symmetrical structure can naturally form a control group during the vibration control of the flexible beam. At the same time, by comparing the outputs of different types of sensors, the experimental content is rich and the demonstration is strong.

[0028] 5. The input and output interfaces are all voltage signals, which are convenient for matching with different types of real-time control systems, and the interfaces have strong adaptability and scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Device structure layout diagram.

[0030] Figure 2a and Figure 2b They are schematic diagrams of the front and back structures of the first flexible beam respectively.

[0031] Figure 3a and Figure 3b They are schematic diagrams of the front and back structures of the second flexible beam respectively.

[0032] Figure 4 Device functional structure block diagram.

[0033] Figure 5 Vibration isolation functional block diagram.

[0034] Figure 6 Functional block diagram of flexible beam vibration control. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0036] like Figure 1 and Figure 4 As shown, an experimental device for simulating active control of satellite platform vibration includes a rigid frame 1, an exciter 2, a connecting rod 3, a high-strength low-deformation rope 4, a cubic satellite model 5, a first flexible beam 6, a second flexible beam 7, a laser displacement meter 8, an accelerometer 9, a power amplifier 10, and a real-time controller 11.

[0037] The length direction of the rigid frame 1, i.e., the X-axis direction, is the working direction of the device. An exciter 2 is installed on one side of the length direction, i.e., the X-axis direction. The exciter 2 is connected to the cubic satellite model 5 through a connecting rod 3. The central axis of the exciter 2 coincides with the center line of the cubic satellite model 5. The cubic satellite model 5 is suspended on the rigid frame 1 by multiple high-strength, low-deformation ropes 4. The multiple high-strength, low-deformation ropes 4 are of equal length, realizing horizontal movement in the working direction, motion constraint in the width direction, and satellite gravity unloading. The small-range free movement in the working direction can simulate the satellite's in-orbit motion state.

[0038] The cubic satellite model 5 is a frame structure. Two flexible beams, a first flexible beam 6 and a second flexible beam 7, are installed by screws in the width direction, that is, at the center position of both sides along the Y-axis direction. The plane where the first flexible beam 6 and the second flexible beam 7 are located is parallel to the vertical plane, that is, the YOZ plane. An accelerometer 9 is installed by screws at the center position on the other side of the cubic satellite model 5 corresponding to the exciter 2. At the same time, a laser displacement meter measuring point is set on the horizontal line adjacent to the accelerometer 9. The laser displacement meter 8 is fixed to the rigid frame 1 by a bracket, and the measurement signals of the laser displacement meter 8 and the accelerometer 9 are output to the real-time controller 11.

[0039] like Figure 5As shown, the connecting rod 3 is a functional device capable of axially outputting force and displacement, and has two operating modes. When the connecting rod 3 is de-energized and inactive, serving only as a mechanical connection between the vibrator 2 and the CubeSat model 5, the vibrator 2 drives the CubeSat model 5 and the first and second flexible beams 6 and 7, the loads mounted on the CubeSat model, to vibrate. The connecting rod 3 utilizes a piezoelectric stack as its primary driving element, and since the operating voltage of the piezoelectric stack is typically positive, when powered and uncontrolled, the piezoelectric stack in the connector 3 operates at a mid-range of the maximum driving voltage. Increasing the voltage above this mid-range causes the connecting rod to extend and output thrust, while decreasing the voltage below the mid-range causes the connecting rod to contract relative to the powered and uncontrolled state, outputting tension. Therefore, when powered and operating, the connecting rod 3 acts as a vibration isolation device for the CubeSat model. In conjunction with the accelerometer 8 or laser displacement meter 9 and the real-time controller 11, it can isolate the vibrations of the vibrator 2 and the CubeSat model 5, achieving stable control of the CubeSat platform. The vibration isolation control process is generally as follows: When the vibrator 2 vibrates the CubeSat model 5 through the conduction of the connecting rod 3, the accelerometer 9 and laser displacement meter 8 can measure the vibration of the CubeSat model 5 along the X direction. After obtaining the measurement signal from the accelerometer 9 or laser displacement meter 8, the real-time controller 11 calculates and outputs a control signal, which acts on the connecting rod 3 through the power amplifier 10. This causes the connecting rod 3 to output a displacement opposite to the vibration direction of the CubeSat model 5, reducing the vibration of the CubeSat model 5 to zero, thus achieving vibration isolation between the vibrator 2 and the CubeSat model 5.

[0040] The first flexible beam 6 and the second flexible beam 7 have the same structure and are made of the same material. The bottom is a T-shaped structure with four mounting holes on the root end face. They are fixed to the center of the cubic satellite model by four screws to form a cantilever beam structure, and the width direction is parallel to the vertical direction.

[0041] like Figure 2a and Figure 2b As shown, a first PVDF piezoelectric film 6.1 is pasted on the middle part of the first flexible beam 6, and a second PVDF piezoelectric film 6.2 is pasted on the root, which serve as a vibration measurement sensor. At the same time, a first piezoelectric fiber composite material 6.3 and a second piezoelectric fiber composite material 6.4 of thin film materials are pasted on positions opposite to the first PVDF piezoelectric film 6.1 and the second PVDF piezoelectric film 6.2. The piezoelectric fiber composite material is a thin film type device. After being bonded to the flexible beam, it can output a torque acting on the first flexible beam by using the inverse piezoelectric effect, thereby affecting the vibration state of the first flexible beam.

[0042] like Figure 3a and Figure 3bAs shown, two resistance strain gauges are bonded to each surface of the root of the second flexible beam 7, for a total of four resistance strain gauges on the two surfaces, with the same resistance value, namely the first resistance strain gauge 7.1, the second resistance strain gauge 7.2, the third resistance strain gauge 7.3, and the fourth resistance strain gauge 7.4. The four resistance strain gauges form a strain full bridge for measuring the deformation of the root of the second flexible beam 7. Two resistance strain gauges are bonded to each surface of the middle part of the second flexible beam 7, for a total of four resistance strain gauges on the two surfaces, with the same resistance value, namely the fifth resistance strain gauge 7.5, the sixth resistance strain gauge 7.6, the seventh resistance strain gauge 7.7, and the eighth resistance strain gauge 7.8. The four resistance strain gauges form a strain full bridge for measuring the deformation of the middle part of the second flexible beam 7.

[0043] After the resistance strain gauge is bonded to the second flexible beam 7, a third piezoelectric fiber composite material 7.9 is bonded near the base, and a fourth piezoelectric fiber composite material 7.10 is bonded to the middle. These two piezoelectric fiber composite materials are independently connected to a power amplifier 10. This utilizes the inverse piezoelectric effect to generate a torque that acts on the second flexible beam, affecting its vibration state.

[0044] like Figure 6 As shown, the CubeSat model 5 integrates a strain signal processing module and a charge signal processing module. The strain bridge signal output on the second flexible beam 7 is introduced into the strain signal processing module of the CubeSat model 5, and after amplification, the strain signal is output to the input end of the real-time controller 11. The charge signal output by the PVDF piezoelectric film on the first flexible beam 6 is introduced into the charge signal processing module of the CubeSat model 5, and after amplification, it is output as a voltage signal to the input end of the real-time controller 11.

[0045] The power amplifier 10 has multiple input and output channels, the input end is connected to the output end of the real-time controller 11, and the output end of the power amplifier 10 is connected to the first piezoelectric fiber composite material 6.3, the second piezoelectric fiber composite material 6.4, the third piezoelectric fiber composite material 7.9, the fourth piezoelectric fiber composite material 7.10 and the connecting rod 3.

[0046] The real-time controller 11 is integrated with an analog-to-digital conversion module, which can collect the processed signals generated by the strain bridge and the signals generated by the PVDF piezoelectric film, perform calculations on the controller, convert the calculated digital quantities into digital-to-analog quantities, and output an analog voltage for control. The voltage amplified by the power amplifier acts on the piezoelectric fiber composite materials of the first flexible beam 6 and the second flexible beam 7, so that the flexible beams are subjected to a torque, causing the flexible beams to produce a deformation opposite to the current vibration state, thereby realizing vibration control of the flexible beams.

[0047] The real-time controller 11 is flexible in form and is essentially an embedded data processor that integrates data processing and closed-loop control software. It collects the output signals of various sensors and sends them to the data processor, which can perform active vibration control of the flexible beam and active vibration isolation of the cubic satellite model.

[0048] The method of using a simulated satellite platform vibration active control experimental device is as follows:

[0049] First, the vibrator 2 operates in a sweep frequency mode, so that the first flexible beam 6 and the second flexible beam 7 on the cubic satellite model enter a sweep frequency vibration state. The output signals of the two PVDF piezoelectric films on the first flexible beam 6 and the output signals of the two strain bridges on the second flexible beam 7 are collected and processed by the real-time controller 11, and the first two natural frequencies of the measured flexible beam can be obtained. Alternatively, the strain signal processed by the strain signal processing module and the charge signal processed by the charge signal processing module are output to an external measuring device, and the first two natural frequencies of the first flexible beam 6 and the second flexible beam 7 can also be measured. A certain frequency point in the first two orders can be selected for excitation to put the flexible beam in a certain order of resonance. When one of the two flexible beams is controlled and the other is not controlled and only monitored, the motion state of the two flexible beams during vibration control can be compared to intuitively evaluate the control effect.

[0050] The connecting rod 3 in the present invention can operate in both active and passive modes. In the passive mode, it is de-energized and only transmits vibration. In the active mode, the connecting rod 3 can output force and displacement, and the accelerometer 9 or laser displacement meter 8 can measure the vibration of the CubeSat model. These two modes operate differently but function in the same way. When active flexible beam vibration control is being performed, the CubeSat model is in a vibrating state, and the accelerometer 9 or laser displacement meter 8 can monitor the vibration of the CubeSat model. The real-time controller runs a closed-loop control algorithm to calculate the control variable. This digital control variable is then converted from a digital-to-analog converter to an analog voltage signal. This analog voltage signal is amplified by a power amplifier and output to the connecting rod 3. Under the control of the driving voltage, the connecting rod 3 outputs a displacement in the opposite direction of the current vibration, thereby suppressing the vibration of the CubeSat model platform and achieving active isolation of the platform vibration.

[0051] The experimental device designed in this invention achieves gravity unloading through suspension, while also scientifically designing a flexible structure installation method to reduce the influence of ground gravity and effectively simulate the microgravity environment of space. The use of multiple sensors to feedback vibration states helps demonstrate the measurement characteristics of different sensors, and the symmetrical arrangement of flexible structures on both sides enables sharp state contrast, facilitating a visual display of experimental results. Combined with signal processing circuits and real-time control systems, the device can effectively simulate structural vibrations in space environments and study vibration control technology, with broad application prospects in experimental research and teaching.

Claims

1. An experimental device for simulating active control of satellite platform vibration, characterized by: The invention comprises a rigid frame (1), an exciter (2), a connecting rod (3), a high-strength low-deformation rope (4), a cubic satellite model (5), a first flexible beam (6), a second flexible beam (7), a laser displacement meter (8), an accelerometer (9), a power amplifier (10) and a real-time controller (11); The length direction of the rigid frame (1), i.e., the X-axis direction, is the working direction of the device. An exciter (2) is installed on one side of the length direction, i.e., the X-axis direction. The exciter (2) is connected to the cubic satellite model (5) through a connecting rod (3). The central axis of the exciter (2) coincides with the central line of the cubic satellite model (5). The cubic satellite model (5) is suspended on the rigid frame (1) through a plurality of high-strength, low-deformation ropes (4). The plurality of high-strength, low-deformation ropes (4) are of equal length, so as to realize horizontal movement in the working direction, motion constraint in the width direction, realize satellite gravity unloading, and free movement in a small range in the working direction, thereby simulating the satellite's on-orbit motion state. The cubic satellite model (5) is a frame structure, and a first flexible beam (6) and a second flexible beam (7) are installed at the center positions of the two side surfaces in the width direction, i.e., along the Y-axis direction, to form a cantilever beam structure; an accelerometer (9) is installed on the other side of the cubic satellite model (5) corresponding to the exciter (2); and a laser displacement meter measuring point is set on a horizontal line adjacent to the accelerometer (9); the laser displacement meter (8) is fixed on the rigid frame (1), and the measurement signals of the laser displacement meter (8) and the accelerometer (9) are output to a real-time controller (11); The connecting rod (3) uses the piezoelectric stack as a basic driving element and is a functional device that can output force and displacement along the axial direction and has two working modes; when the connecting rod (3) is not powered and does not actively work and only serves as a mechanical connection between the exciter (2) and the cubic satellite model (5), the exciter (2) drives the cubic satellite model (5) and the load first flexible beam (6) and second flexible beam (7) installed on the cubic satellite model to vibrate; the working voltage of the piezoelectric stack in the connecting rod is a positive voltage. When the power is on and the control is not performed, the piezoelectric stack in the connecting rod (3) works When the voltage is set at the middle value of the maximum driving voltage, an increase in the voltage based on this value will cause the connecting rod to extend and output thrust, and a decrease in the voltage based on the middle value of the maximum driving voltage will cause the connecting rod to contract and output tension relative to the uncontrolled state when powered on. Therefore, when the connecting rod (3) is powered on and works, it can be used as a device for isolating the vibration of the cubic satellite model, and can be used in conjunction with an accelerometer (9) or a laser displacement meter (8) and a real-time controller (11) to achieve vibration isolation between the exciter (2) and the cubic satellite model (5), thereby achieving stable control of the cubic satellite platform. The first flexible beam (6) and the second flexible beam (7) have the same structure and are made of the same material. Two PVDF piezoelectric films are attached to the first flexible beam (6) to serve as vibration measurement sensors, and two piezoelectric fiber composite materials are attached to positions opposite to the two PVDF piezoelectric films. The piezoelectric fiber composite material is a thin film device that is bonded to the flexible beam and uses the inverse piezoelectric effect to output a torque acting on the first flexible beam, thereby affecting the vibration state of the first flexible beam. Eight resistance strain gauges are attached to the second flexible beam (7), and four resistance strain gauges form a group to form a strain full bridge, which is used for deformation measurement of the middle part of the second flexible beam (7); The second flexible beam (7) is bonded with a piezoelectric fiber composite material near the two strain full bridges, and the two piezoelectric fiber composite materials are independently connected to a power amplifier (10), and the inverse piezoelectric effect is used to output a torque acting on the second flexible beam, thereby affecting the vibration state of the second flexible beam; The cubic satellite model (5) internally integrates a strain signal processing module and a charge signal processing module; the strain bridge signal output on the second flexible beam (7) is introduced into the strain signal processing module of the cubic satellite model (5), and after amplification processing, the strain signal is output to the input end of the real-time controller (11); the PVDF piezoelectric film output charge signal on the first flexible beam (6) is introduced into the charge signal processing module of the cubic satellite model (5), and after amplification processing, the voltage signal is output to the input end of the real-time controller (11); The power amplifier (10) has multiple input and output channels, the input end is connected to the output end of the real-time controller (11), and the output end of the power amplifier (10) is connected to the piezoelectric fiber composite material of the first flexible beam (6) and the second flexible beam (7) and the connecting rod (3); An analog-to-digital conversion module is integrated on the real-time controller (11) to collect the processed signals generated by the strain bridge and the signals generated by the PVDF piezoelectric film, perform operations on the real-time controller (11), convert the digital quantities into digital-to-analog quantities, and output an analog voltage for control. The voltage amplified by the power amplifier acts on the piezoelectric fiber composite materials of the first flexible beam (6) and the second flexible beam (7), so that the flexible beams are subjected to torque, causing the flexible beams to produce a deformation opposite to the current vibration state, thereby realizing vibration control of the flexible beams.

2. The active control experimental device for simulating satellite platform vibration according to claim 1, characterized in that: The real-time controller (11) realizes the vibration isolation control process of the exciter (2) and the cubic satellite model (5) as follows: when the exciter (2) causes the cubic satellite model (5) to vibrate through the conduction of the connecting rod (3), the accelerometer (9) and the laser displacement meter (8) can measure the vibration of the cubic satellite model (5) along the X direction; after the real-time controller (11) obtains the measurement signal of the accelerometer (9) or the laser displacement meter (8), it calculates and outputs a control signal to act on the connecting rod (3) through the power amplifier (10), so that the connecting rod (3) outputs a displacement opposite to the vibration direction of the cubic satellite model (5), so that the vibration of the cubic satellite model (5) is reduced and tends to zero, thereby realizing vibration isolation between the exciter (2) and the cubic satellite model (5).

3. The active control experimental device for simulating satellite platform vibration according to claim 1, characterized in that: The plane where the first flexible beam (6) and the second flexible beam (7) are located is parallel to the vertical plane, that is, the YOZ plane.

4. The active control experimental device for simulating satellite platform vibration according to claim 1, characterized in that: A first PVDF piezoelectric film (6.1) is adhered to the middle portion of the first flexible beam (6), and a second PVDF piezoelectric film (6.2) is adhered to the root portion, serving as a vibration measurement sensor. Simultaneously, a first piezoelectric fiber composite material (6.3) and a second piezoelectric fiber composite material (6.4) made of thin film materials are adhered to positions opposite to the first PVDF piezoelectric film (6.1) and the second PVDF piezoelectric film (6.2). The piezoelectric fiber composite material is a thin film device that, after being adhered to the flexible beam, can output a torque acting on the first flexible beam using the inverse piezoelectric effect, thereby affecting the vibration state of the first flexible beam.

5. The active control experimental device for simulating satellite platform vibration according to claim 1, characterized in that: Two resistance strain gauges are bonded to each surface of the root of the second flexible beam (7), and there are four resistance strain gauges on the two surfaces. The four resistance strain gauges have the same resistance value, and they are respectively the first resistance strain gauge (7.1), the second resistance strain gauge (7.2), the third resistance strain gauge (7.3), and the fourth resistance strain gauge (7.4). The four resistance strain gauges form a strain full bridge for measuring the deformation of the root of the second flexible beam (7); two resistance strain gauges are bonded to each surface of the middle part of the second flexible beam (7), and there are four resistance strain gauges on the two surfaces. The four resistance strain gauges have the same resistance value, and they are respectively the fifth resistance strain gauge (7.5), the sixth resistance strain gauge (7.6), the seventh resistance strain gauge (7.7), and the eighth resistance strain gauge (7.8). The four resistance strain gauges form a strain full bridge for measuring the deformation of the middle part of the second flexible beam (7).

6. The active control experimental device for simulating satellite platform vibration according to claim 5, characterized in that: After the resistance strain gauge is bonded to the second flexible beam (7), a third piezoelectric fiber composite material (7.9) is bonded to the side near the root, and a fourth piezoelectric fiber composite material (7.10) is bonded to the middle portion. The two piezoelectric fiber composite materials are independently connected to a power amplifier (10), and the inverse piezoelectric effect is used to output a torque acting on the second flexible beam, thereby affecting the vibration state of the second flexible beam.

7. A method for using the simulated satellite platform vibration active control experimental device according to any one of claims 1 to 6, characterized in that: The details are as follows: First, the exciter (2) operates in a sweep frequency mode, so that the first flexible beam (6) and the second flexible beam (7) on the cubic satellite model enter a sweep frequency vibration state; the output signals of the two PVDF piezoelectric films on the first flexible beam (6) and the output signals of the two strain bridges on the second flexible beam (7) are collected and processed by the real-time controller (11) to obtain the first two natural frequencies of the measured flexible beam; Alternatively, the strain signal processed by the strain signal processing module and the charge signal processed by the charge signal processing module are output to an external measuring device to measure the first two natural frequencies of the first flexible beam (6) and the second flexible beam (7); a certain frequency point in the first two orders is selected for excitation, so that the flexible beam is in a certain resonance state; when one of the two flexible beams is controlled and the other is not controlled and only monitored, the motion states of the two flexible beams during vibration control are compared, so that the control effect can be intuitively evaluated; The connecting rod (3) can work in active and passive modes. In the passive mode, no power is supplied and only vibration is transmitted. In the active mode, the connecting rod (3) outputs force and displacement, and the accelerometer (9) or the laser displacement meter (8) measures the vibration of the cubic satellite model. When the flexible beam vibration is actively controlled, the cubic satellite model is in a vibrating state, and the accelerometer (9) or the laser displacement meter (8) monitors the vibration of the cubic satellite model. The real-time controller runs a closed-loop control algorithm to calculate the control quantity, and the control digital quantity outputs an analog voltage signal after passing through a digital-to-analog conversion circuit. The analog voltage signal is amplified by a power amplifier (10) and output to the connecting rod (3). Under the control of the driving voltage, the connecting rod (3) outputs a displacement opposite to the current vibration direction, so that the vibration of the cubic satellite model platform is suppressed, thereby realizing active isolation of the platform vibration.

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