A flexible solar array satellite active vibration control method and device for SADA disturbance

Abstract

The application provides a flexible sailboard satellite active vibration control method and device for SADA disturbance, and belongs to the field of spacecraft attitude determination and control. The method solves the stability problem caused by frequency drift in the prior art, and solves the problem that the satellite model cannot adapt to the time-varying system. The method comprises the following steps: collecting SADA driving angle, fiber-optic gyroscope angular velocity and piezoelectric sensor voltage data; performing discrete short-time Fourier transform on the voltage data to obtain amplitude spectrum and phase spectrum; identifying the frequency corresponding to the amplitude peak value according to the amplitude spectrum, and associating the SADA driving angle corresponding to the peak value and the fiber-optic gyroscope angular velocity; judging the whole-satellite stability according to the fiber-optic gyroscope angular velocity, and adjusting the control parameters of the piezoelectric actuator in sections when the angular velocity exceeds the set threshold; and iteratively executing the above steps until the whole-satellite stability along the whole orbit meets the index requirement. The method is mainly used in the field of satellite control.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of spacecraft attitude determination and control, and particularly relates to a flexible solar panel satellite active vibration control method for SADA disturbance. BACKGROUND

[0002] With the rapid development of the satellite industry, the demand for energy supply of high-power satellite payloads is increasing, which promotes the use of super-large size solar wings. Compared with the satellite body, super-large size flexible solar wings can provide more abundant energy, but at the same time, it introduces significant stable control challenges. For example, when a satellite with a large size flexible solar panel is in orbit, if the base frequency of the solar panel is not clearly identified or the control strategy is not appropriate, frequent flexible vibration may cause structural fatigue, reduce the service life of the solar panel, and even cause the whole satellite to lose stability, so that the stability cannot meet the task requirements. In a more serious case, the flywheel is overheated and damaged due to frequent acceleration and deceleration, thereby shortening the service life of the whole satellite. These defects have appeared many times in actual tasks.

[0003] The existing attitude control method of the satellite with a large flexible solar panel in orbit mainly depends on adjusting the control bandwidth to avoid dangerous frequencies to achieve stability. Specifically, the traditional controller will reserve sufficient stability margin at the flexible modal frequency when designed, and usually set the control bandwidth below the first order flexible frequency to avoid exciting vibration. For example, some satellite systems use a linear time-invariant controller to suppress vibration by fixing parameters, but this method has limitations when facing large size solar panels. As the size of the solar panel increases, and the whole satellite and the solar panel are connected through the solar array drive assembly (SADA), the rotation of the SADA makes the solar panel sun-oriented, but at the same time, it also introduces complex dynamics. In finite element analysis, the vibration modal frequency and mode shape of the large flexible solar panel are highly dependent on the boundary conditions of the SADA; when the SADA rotates and locks, the internal motor and other mechanical structures form a specific mechanical impedance, which is different from the state of the solar panel floating freely or at other rotation angles. Therefore, different rotation angles of the SADA correspond to different clamped conditions, resulting in the drift of the natural frequency of the solar panel. The existing technology cannot adapt to this drift in real time, for example, when the SADA rotation causes the frequency to drift downward and enter the control bandwidth, the control force will instead feed back to the vibration mode, causing the vibration to diverge.

[0004] In addition, the traditional vibration suppression strategy can only continuously reduce the control bandwidth when facing flexible structures with increasingly lower fundamental frequency, which leads to the loss of the ability of the whole satellite to quickly maneuver and the solar panel to quickly rotate. For example, in some key energy acquisition conditions, the satellite cannot timely adjust the attitude to optimize the sun orientation, thereby reducing the use efficiency of the whole satellite. At the same time, the continuous rotation process of the SADA makes the dynamic parameters present periodic time-varying characteristics, and the nonlinear time-invariant system; the friction, gear clearance and other nonlinear factors in the SADA driving process can further excite the vibration of the solar panel. However, due to the ground test conditions, the existing technology cannot accurately obtain or establish the model of these time-varying parameters, for example, the ground simulation cannot completely reproduce the SADA behavior in the space environment, so that the model parameters are deviated. The traditional controller is designed for a linear time-invariant system, and does not have the ability to track and adapt to time-varying dynamics; when the parameter variation of the time-varying system is fast enough or the amplitude is large enough, the stability margin of the fixed controller is quickly consumed, resulting in instability of the system at a specific working point.

[0005] Although the active vibration control method can enhance the rigidity of the flexible solar wing and improve the system stability through active control, the existing active control method highly depends on the establishment of a high-precision satellite model. For example, these methods usually optimize the control parameters based on the model parameters obtained through ground tests, and always apply the same set of parameters. However, when the model parameters are inaccurate, the calculated control parameters can cause positive feedback, which can even lead to instability of the whole satellite control. This model dependence limits its adaptability in orbit and cannot effectively cope with the dynamic changes caused by the SADA rotation. SUMMARY

[0006] Therefore, the present application aims to provide a flexible solar panel satellite active vibration control method and device for SADA disturbance, to solve the stability problem caused by the frequency drift of the prior art, and the problem of dependence on the satellite model and inability to adapt to time-varying systems.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A flexible solar panel satellite active vibration control method for SADA disturbance, the method comprising:

[0009] Step 1: Install symmetrically arranged piezoelectric sensors and piezoelectric actuators on the solar panel, collect the SADA driving angle of the whole satellite body in the on-orbit three-axis-to-ground and the solar panel controlled rotation tracking sun condition, the angular velocity of the fiber optic gyroscope, and the voltage data of the piezoelectric sensor;

[0010] Step 2: Discrete short-time Fourier transform is performed on the voltage data of the piezoelectric sensor to obtain the amplitude spectrum and the phase spectrum;

[0011] Step 3: According to the amplitude spectrum, identify the frequency corresponding to the amplitude peak value as the target frequency for priority suppression of active vibration control, and associate the SADA driving angle corresponding to the peak value and the angular velocity of the fiber optic gyroscope;

[0012] Step 4: According to the angular velocity of the fiber optic gyroscope, judge the stability of the whole satellite, when the angular velocity exceeds the set threshold, adjust the control parameters of the piezoelectric actuator, the control parameters are segmented according to the SADA driving angle and the angular velocity;

[0013] Step 5: Iteratively execute steps 1 to 4 until the whole satellite stability meets the index requirements.

[0014] Further, a preferred mode is also proposed, and the measurement equation of the piezoelectric sensor is:

[0015]

[0016] Wherein, is the voltage value measured by the piezoelectric sensor, is a coefficient related to the piezoelectric material itself, is the modal shape derivative difference matrix, is the modal coordinate.

[0017] Further, a preferred mode is also proposed, and the calculation formula of the discrete short-time Fourier transform in step 2 is:

[0018]

[0019] Wherein, represents the complex spectrum value at the th time frame, the th frequency index, represents the sampling value of the original signal at , represents the value of the window function at position, L represents the window length, that is, the number of sampling points analyzed per frame, represents the natural constant, that is, 2.71828, represents the imaginary unit, which satisfies , k represents the frequency index value, represents the frame index value, the value range is , N represents the Fourier transform point number, is the window function; w

[0020] The amplitude spectrum and the phase spectrum are calculated by the following formula:

[0021]

[0022] ​

[0023] in, Indicates amplitude spectrum, Represents the phase spectrum. express The real part, express The imaginary part, It represents a complex argument.

[0024] Furthermore, a preferred method is proposed, wherein the window function of the discrete short-time Fourier transform in step 2 is the Hanning window.

[0025] Furthermore, a preferred method is proposed, wherein the amplitude spectrum identification is based on the global maximum value of the amplitude spectrum, the amplitude frequency of which corresponds to the flexible mode frequency drift caused by SADA selection, and is used as the target frequency of the MPPF controller.

[0026] Furthermore, a preferred embodiment is proposed, wherein the piezoelectric actuator in step 4 is controlled by an MPPF controller, which includes a second-order compensator and a first-order compensator, specifically as follows:

[0027]

[0028] in, Indicates the first The first mode in the first Second derivatives of the state variables of the second-order compensator at each control node. Indicates control damping, Indicates the control frequency. Indicates the first The first mode in the first The first derivative of the state variables of the second-order compensator of each control node. Indicates the first The first mode in the 1st order The state variables of the second-order compensator of each control node. Indicates the first The measured voltage value of the piezoelectric sensor at each control node. Indicates the first The first mode in the 1st order The first derivative of the state variables of the first-order compensator of each control node. Indicates the first The first mode in the first The state variables of the first-order compensator of each control node. Indicates the first The first mode in the 1st order The component of the voltage applied by the actuator of each control node. and This indicates the control parameters.

[0029] Further, a preferred mode is proposed, the control frequency According to the amplitude peak frequency identified in step 3, the control parameter And According to the angle and angular velocity segment adjustment of SADA, the segment adjustment adopts a table lookup mode, the segment region is identified based on the out-of-tolerance region, and the control parameter of the piezoelectric actuator in the in-tolerance region is set to 0.

[0030] Based on the same inventive concept, the application also proposes a flexible sailboard satellite active vibration control device for SADA disturbance, which comprises:

[0031] A data acquisition unit is configured to acquire SADA driving angle, fiber optic gyroscope angular velocity and piezoelectric sensor voltage data in the three-axis-to-ground and sailboard-controlled-rotation-to-sun working conditions of the on-orbit whole satellite body;

[0032] A Fourier transform unit is configured to perform discrete short-time Fourier transform on the voltage data of the piezoelectric sensor to obtain amplitude spectrum and phase spectrum;

[0033] An amplitude spectrum identification unit is configured to identify the frequency corresponding to the amplitude peak value from the amplitude spectrum as the target frequency for priority suppression of active vibration control, and associate the peak value with the SADA driving angle and the fiber optic gyroscope angular velocity;

[0034] A judgment unit is configured to judge the whole satellite stability according to the fiber optic gyroscope angular velocity, and adjust the control parameter of the piezoelectric actuator when the angular velocity exceeds a set threshold, wherein the control parameter is adjusted in segments according to the SADA driving angle and the angular velocity;

[0035] An iteration unit is configured to iteratively execute the process from the data acquisition unit to the judgment unit until the whole satellite stability meets the index requirements throughout the orbit.

[0036] Based on the same inventive concept, the application also proposes a computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the active vibration control method for SADA disturbance of the flexible sailboard satellite according to any one of the above.

[0037] Based on the same inventive concept, the application also proposes a computer readable storage medium, which stores a computer program, and when the computer program is run by a processor, the steps of the active vibration control method for SADA disturbance of the flexible sailboard satellite according to any one of the above are executed.

[0038] Compared with the prior art, the application has the following beneficial effects:

[0039] Firstly, the prior art mostly adopts a linear time-invariant controller, relies on fixed model parameters obtained by ground testing, and avoids dangerous frequencies by setting a fixed control bandwidth. For example, the traditional method sets the bandwidth below the first-order flexible frequency, but cannot adapt to the change of boundary conditions caused by SADA rotation. When the SADA rotation causes the inherent frequency of the sail plate to drift into the control bandwidth, the fixed controller will cause positive feedback and exacerbate vibration. The present application discards this static model dependence, collects voltage data in real time through a piezoelectric sensor, combines short-time Fourier transform for online frequency identification, and directly adjusts the control parameters for the dynamic working condition in orbit, thereby avoiding instability caused by frequency drift.

[0040] Secondly, the prior art lacks adaptability to time-varying systems. During the continuous rotation of SADA, nonlinear factors such as friction and gear clearance cause the dynamics parameters to periodically change, but the traditional controller is designed for linear time-invariant systems and cannot quickly respond to parameter changes. The present application uses the segmented parameter adjustment mechanism of the MPPF (Multi-Modal Positive Position Feedback) controller, uses the SADA angle and angular velocity as the basis for segmentation, and uses a table lookup method for nonlinear partitioning. Control parameters are set individually for the out-of-tolerance area, rather than globally fixed parameters, so that the controller can adapt to the time-varying characteristics of SADA rotation and avoid stable margin consumption. Through online identification and parameter adjustment, the stability of the whole satellite is improved by more than 20%.

[0041] Finally, the prior art often sacrifices maneuverability to avoid the risk of inaccurate model, such as reducing the control bandwidth to cause the whole satellite to be unable to maneuver quickly or the sail plate to be quickly oriented towards the sun. The present application dynamically adjusts the parameters under the premise of ensuring stability through closed-loop iterative optimization. The initial control parameter is set to zero, and the piezoelectric actuator is activated only when the fiber-optic gyroscope detects that the stability is out of tolerance, realizing on-demand control, which improves the precision while retaining the maneuverability of the satellite.

[0042] The present application is applied to the field of satellite control. BRIEF DESCRIPTION OF DRAWINGS

[0043] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the present application illustrated in the drawings and their descriptions are used to explain the present application and are not intended to limit the present application. In the drawings:

[0044] Figure 1 A flowchart of a flexible sail plate satellite active vibration control method for SADA disturbance according to the present application;

[0045] Figure 2A schematic diagram of the satellite according to the present application, wherein 1 is a solar panel, 2 is a satellite body, 3 is an A-axis of the SADA, 4 is a B-axis of the SADA, A1, A2, A3, A4, A5 all represent piezoelectric actuators, and S1, S2, S3, S4, S5 all represent piezoelectric sensors;

[0046] Figure 3 A schematic diagram of the two-axis driving angle of the SADA according to the present application;

[0047] Figure 4 A schematic diagram of the two-axis driving angular velocity of the SADA according to the present application;

[0048] Figure 5 A schematic diagram of the satellite angular velocity when no active control is performed according to the present application;

[0049] Figure 6 A schematic diagram of the measured piezoelectric voltage data according to the present application;

[0050] Figure 7 A frequency spectrum diagram calculated by using piezoelectric data in the out-of-tolerance time region according to the present application;

[0051] Figure 8 A schematic diagram of the two-axis driving angle of the SADA when the satellite angular velocity is out of tolerance according to the present application, wherein AngleA represents the driving rotation angle of the A-axis, and AngleB represents the driving rotation angle of the B-axis;

[0052] Figure 9 A schematic diagram of the two-axis driving angular velocity of the SADA when the satellite angular velocity is out of tolerance according to the present application, wherein OmgA represents the driving rotation angular velocity of the A-axis, and OmgB represents the driving rotation angular velocity of the B-axis;

[0053] Figure 10 A frequency spectrum diagram after the piezoelectric control parameters are modified according to the present application;

[0054] Figure 11 A schematic diagram of the satellite angular velocity after the control parameters are modified according to the present application, wherein OmgNone represents the satellite angular velocity when no active vibration control is performed, and OmgPPF represents the satellite angular velocity after the active vibration control is performed. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0056] Embodiment one, see Figure 1The embodiment is illustrated. The embodiment aims at the stability problem caused by the frequency drift of the prior art and the problem that the satellite model cannot adapt to the time-varying system, and proposes an active vibration control method for SADA disturbance of a flexible solar panel satellite, the method comprising:

[0057] Step 1: install symmetrically arranged piezoelectric sensors and piezoelectric actuators on the solar panel, collect SADA driving angles of the whole satellite body in the three-axis-to-ground and the solar panel controlled rotation tracking-to-sun working conditions, the angular velocity of the fiber optic gyroscope, and the voltage data of the piezoelectric sensor;

[0058] Step 2: perform discrete short-time Fourier transform on the voltage data of the piezoelectric sensor to obtain amplitude spectrum and phase spectrum;

[0059] Step 3: identify the frequency corresponding to the amplitude peak value according to the amplitude spectrum as the target frequency for priority suppression of active vibration control, and associate the SADA driving angle and the angular velocity of the fiber optic gyroscope corresponding to the peak value;

[0060] Step 4: determine the stability of the whole satellite according to the angular velocity of the fiber optic gyroscope, and when the angular velocity exceeds the set threshold, adjust the control parameters of the piezoelectric actuator, the control parameters being segmented and adjusted according to the SADA driving angle and the angular velocity;

[0061] Step 5: iteratively execute steps 1 to 4 until the stability of the whole satellite meets the index requirements.

[0062] The technical principle core of the method proposed in the embodiment is to overturn the traditional fixed mode of modeling first and then controlling, and to propose an online identification and segmented adaptive active vibration control method, thereby effectively solving the core problem that the dynamics parameters of the solar panel are time-varying due to the rotation of the SADA (solar cell panel driving mechanism), which cannot be coped with by the traditional controller.

[0063] The prior art completely relies on inaccurate fixed model parameters obtained through ground tests to design the controller. The method proposed in the embodiment discards the dependence on inaccurate prior models, and the basic principle is to use the voltage data of the piezoelectric sensor in on-orbit operation as the input variable directly reflecting the real vibration state of the solar panel, and through short-time Fourier transform on the voltage signal, the actual dominant vibration frequency and amplitude of the solar panel under the current SADA angle and angular velocity can be collected and analyzed in real time. This sensing method based on real on-orbit data realizes the accurate and online capture of the frequency drift phenomenon under different SADA angles for the first time.

[0064] The traditional linear time-invariant controller adopts a unified processing mode for all working conditions, which is the root cause of its failure in front of the SADA rotation related time-varying system. The core principle of the embodiment is to realize that the angle and angular velocity of the SADA jointly define a time-varying working condition point, and a control parameter segmentation strategy based on the combination of the SADA angle and angular velocity is proposed. It is not simply segmented at equal intervals, but by monitoring whether the fiber optic gyroscope angular velocity is out of tolerance to locate the problem working condition area, and a mapping relationship between the area and the dominant frequency identified by the piezoelectric sensor is established. Finally, the control parameter lookup table enables the controller to actively switch to the optimal control parameter group according to the real-time SADA motion state.

[0065] The prior art passively avoids flexible vibration by limiting the control bandwidth and sacrificing maneuverability. The embodiment adopts a multi-modal positive position feedback (MPPF) controller as the active control execution mechanism. The dominant frequency identified from the piezoelectric sensor is directly set as the core parameter of the MPPF controller. The role of the MPPF controller is no longer to simply suppress the signal, but to actively inject damping into the specific vibration mode of the sailboard. Specifically, its second-order compensator is used to achieve precise control of the SADA at the target frequency, and the first-order compensator is used to widen the damping effect near the frequency. By adjusting the parameters, precise damping matching of the vibration mode is achieved, thereby fundamentally consuming vibration energy.

[0066] Through online identification and adaptive control, the method proposed in the embodiment can effectively suppress the large flexible sailboard vibration caused by SADA disturbance. After adjusting the control parameters for a specific working condition, the originally out-of-tolerance satellite angular velocity is effectively suppressed within the index requirement (less than 0.005° / s), achieving stability within the full orbit range. The method can improve the stability of the whole satellite by more than 20%, which is crucial for high-precision earth observation and scientific exploration missions.

[0067] The method proposed in the embodiment directly actively suppresses the vibration source, which can reduce the vibration amplitude caused by SADA interference by 25%. This not only reduces the interference of vibration on attitude control, but also fundamentally reduces the risk of fatigue damage of flexible structures, helps to prolong the design life of solar wings and even the whole satellite, and avoids the problem of flywheel overheating and damage due to frequent compensation of vibration.

[0068] Since the method proposed in the embodiment is active suppression rather than passive avoidance of vibration, there is no need to excessively sacrifice the control bandwidth for stability. This enables the satellite to restore the rapid maneuvering capability and the rapid rotation capability of the sailboard. In the working condition requiring sun orientation to obtain energy, the satellite can adjust the attitude more quickly, ensuring the efficiency of energy supply and improving the mission performance of the whole satellite.

[0069] The biggest advantage of the method is that it does not depend on the ground model which is difficult to obtain accurately. Through the closed-loop adaptive mechanism, the changes of the dynamic parameters caused by SADA rotation, friction, gear gap, etc. can be automatically adapted, overcoming the fatal defect that the stability margin of the traditional fixed parameter controller is easily exhausted in the time-varying system, and showing strong environmental adaptability and robustness.

[0070] Embodiment two, see Figures 2 to 11 This embodiment is described. This embodiment is a complete embodiment of the flexible sailboard satellite active vibration control method for SADA disturbance described in embodiment one, specifically:

[0071] A flexible sailboard satellite active vibration control method for SADA disturbance, the method comprises:

[0072] Step 1: Install symmetrically arranged piezoelectric sensors and piezoelectric actuators on the solar sail, collect the SADA driving angle of the on-orbit whole satellite body three-axis to the ground, the angular velocity of the fiber optic gyroscope, and the voltage data of the piezoelectric sensor under the condition that the sailboard is controlled to rotate and track the sun;

[0073] The satellite configuration diagram in this embodiment is shown in Figure 2 The satellite body 2 and the solar sail 1 are connected through the solar cell panel driving mechanism (SADA), and the solar cell panel driving mechanism includes the A-axis 3 of the SADA and the B-axis 4 of the SADA; symmetrically arranged piezoelectric sensors Ai and piezoelectric actuators Si are installed on the solar sail 1.

[0074] Step 2: Discrete short-time Fourier transform is performed on the voltage data of the piezoelectric sensor to obtain amplitude spectrum and phase spectrum;

[0075] In this embodiment, the voltage data is plotted according to the measured voltage of the piezoelectric sensor, and short-time Fourier transform is performed, that is, the long-time non-stationary signal is divided into many shorter segments, each segment can be approximately regarded as stationary, and then short-time Fourier transform is performed on each segment to obtain amplitude and phase. And save the corresponding SADA driving angular velocity of the segment;

[0076] The measurement equation of the piezoelectric sensor in this embodiment is:

[0077]

[0078] Among them, is the voltage value measured by the piezoelectric sensor, represents the first voltage value measured by the piezoelectric sensor, represents the i-th voltage value measured by the piezoelectric sensor, is a coefficient related to the piezoelectric material itself, is the modal shape derivative difference matrix, is the modal coordinate.

[0079] The amplitude spectrum and the phase spectrum are obtained by the discrete short-time Fourier transform as follows:

[0080] The calculation formula of the discrete short-time Fourier transform is as follows:

[0081] ,

[0082] wherein, represents a complex spectrum value at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, represents a sampling value of the original signal at the m-th time frame and the n-th frequency index, w represents a sampling value of the original signal at the m-th time frame and the n-th frequency index,

[0083] The amplitude spectrum and the phase spectrum are calculated by the following formula:

[0084] ,

[0085] ,

[0086] represents a real part of the m-th time frame and the n-th frequency index, represents a real part of the m-th time frame and the n-th frequency index, represents a real part of the m-th time frame and the n-th frequency index, represents a real part of the m-th time frame and the n-th frequency index, represents a real part of the m-th time frame and the n-th frequency index.

[0087] For analyzing the modal of the low-frequency structure, the sampling frequency of the piezoelectric sensor is fs, and the frequency resolution is expected to be Δf, so there are L sampling points in total, wherein L=fs / Δf; since the satellite structure has multiple modal responses, the Hanning window is beneficial to the vibration analysis of the satellite in the operation stage in terms of the frequency resolution and leakage suppression, so the window function is selected as the Hanning window.

[0088] Step 3: According to the amplitude spectrum, the frequency corresponding to the amplitude peak value is identified as the target frequency for priority suppression in active vibration control, and the SADA driving angle and the angular velocity of the fiber optic gyroscope corresponding to the peak value are associated.

[0089] The amplitude spectrum in this embodiment is identified based on the global maximum value of the amplitude spectrum, i.e. the peak value with the highest amplitude is found from the amplitude spectrum as the main factor causing structural vibration and affecting attitude accuracy, the amplitude frequency corresponds to the flexible modal frequency drift caused by SADA selection, and serves as the target frequency of the MPPF controller. The peak value should be the target for priority suppression by the active vibration controller, and the corresponding SADA angle and angular velocity are obtained according to step 2.

[0090] Step 4: According to the angular velocity of the fiber optic gyroscope, the stability of the whole satellite is judged, and when the angular velocity exceeds the set threshold, the control parameters of the piezoelectric actuator are adjusted, and the control parameters are adjusted according to the SADA driving angle and angular velocity.

[0091] In this embodiment, the stability of the whole satellite is judged according to the angular velocity data of the fiber optic gyroscope, and when the telemetry frequency of the angular velocity is f yc , and there are N frames of angular velocity exceeding the set threshold (the threshold is set according to the index requirements of the satellite platform, and needs to meet the working requirements of the load) within a specified time T, it is considered that the stability of the whole satellite is out of tolerance. When the stability of the whole satellite meets the requirements, the piezoelectric actuator does not act, and when it is out of tolerance, the piezoelectric actuator adjusts the control voltage for control. Because the SADA rotates periodically under the working condition of the three-axis satellite body to the ground, the control parameters are segmented (segmented by table lookup, because the nonlinear relationship between angle and angular velocity cannot be controlled by equal interval, mainly to identify the out-of-tolerance area and modify the control parameters), and the corresponding piezoelectric actuator driving voltage control parameters are segmented.

[0092] The general form of the flexible structure dynamics equation (i.e. the influence form of the piezoelectric actuator on the modal coordinates) is: , wherein, is the control voltage value output by the piezoelectric actuator, is the control voltage of the first control node, is the control voltage of the Nth control node, is a coefficient related to the piezoelectric material itself, is the second derivative of the flexible modal coordinate, is the damping matrix, is the first derivative of the flexible modal coordinate, is the stiffness matrix, is the modal shape difference matrix.

[0093] The MPPF controller is used to control the control parameters of the piezoelectric actuator, which includes a second-order compensator and a first-order compensator. The second-order compensator is used to achieve accurate control of the SADA at the target frequency, and the first-order compensator is used to increase the damping in a certain frequency range near . The selection is based on the frequency corresponding to the peak amplitude obtained in step 2, including:

[0094]

[0095] in, Indicates the first The first mode in the 1st order Second derivatives of the state variables of the second-order compensator at each control node. Indicates control damping, Indicates the control frequency. Indicates the first The first mode in the 1st order The first derivative of the state variables of the second-order compensator of each control node. Indicates the first The first mode in the 1st order The state variables of the second-order compensator of each control node. Indicates the first The measured voltage value of the piezoelectric sensor at each control node. Indicates the first The first mode in the 1st order The first derivative of the state variables of the first-order compensator of each control node. Indicates the first The first mode in the 1st order The state variables of the first-order compensator of each control node. Indicates the first The first mode in the 1st order The component of the voltage applied by the actuator of each control node. and This indicates the control parameters.

[0096] The control frequency described in this embodiment Based on the peak amplitude frequency identified in step 3, the control parameters are set. and The adjustment is segmented according to the angle and angular velocity of the SADA. The segmented adjustment adopts a lookup table method. The segmented area is identified based on the out-of-tolerance area. The piezoelectric actuator control parameters are set to 0 in the non-out-of-tolerance area.

[0097] Step 5: Adjust the control frequency of the piezoelectric actuator And modify parameters as needed , Then, iteratively execute steps 1 to 4 until the overall satellite stability meets the target requirements across the entire orbit.

[0098] In this embodiment, the satellite's orbital altitude is set to 500km and the orbital inclination angle to 50°.

[0099] The moment of inertia of the central rigid body is set as: [155.4 2.3 20; 2.3 387.9 5.1; 20 5.1 512.3] ;

[0100] The moment of inertia of the sailboard is set as: [1145.9 -0.217 0.178; -0.217 40.4 -0.015; 0.178 -0.015 1170] ;

[0101] The rotational-flexural coupling coefficient is:

[0102] ;

[0103] The first three order frequencies of the sailboard are 0.082Hz, 0.131Hz and 0.172Hz respectively. According to the vibration mode of the sailboard, only the single order frequency is considered, and the initial control parameters , and the control frequency are set as: 0, 0 and 0Hz respectively.

[0104] Taking the beta angle of 30 degrees as an example, the SADA two-axis angle and angular velocity driving of the sailboard are shown in Figure 3 and Figure 4 . By analyzing the stability of the whole satellite under different SADA driving angular velocities, that is, the angular velocity is within the range of the overshoot (set as 0.005° / s), the control parameters are modified to suppress the overshoot after the frequency spectrum analysis, and if the stability meets the requirements, the piezoelectric active control is not performed.

[0105] As shown in Figure 5 and Figure 6 , the Fourier frequency spectrum analysis is performed on the piezoelectric voltage data in the overshoot region, the window function is selected as the Hanning window, the sampling frequency is 20Hz, and the segment length is set as 1000, and the frequency spectrum as shown in Figure 7 is obtained. The corresponding driving angle and angular velocity region of the sailboard is found, as shown in Figure 8 and Figure 9 . According to the Figure 7 spectrum, the frequency at the overshoot is 0.18Hz, the piezoelectric control frequency is set as 0.18Hz, is set as 2, is set as 38. The spectrum after analyzing and modifying the control parameters is shown in Figure 10 , and the peak value at 0.18Hz is weakened.

[0106] The angular velocity in the time domain in this region is modified as Figure 11As shown, the previously excessive angular velocity meets the index requirement of less than 0.005° / s, representing that the parameter modification is effective, the corresponding piezoelectric control parameters of the region are saved, when the angle of the A-axis of the SADA is in the range of [50°~120°] and the angular velocity of the A-axis is in the range of [-0.05° / s~0.05° / s] and the angle of the B-axis of the SADA is in the range of [-150°~-140°] and the angular velocity of the B-axis is in the range of [-0.05° / s~-0.12° / s], the parameters are used for control, and in the region without exceeding the index, the piezoelectric control parameters are all set to 0; the steps 1 to 4 are repeated for parameter adjustment and control in all the excessive regions until the stability of the whole satellite meets the index requirement.

[0107] The active vibration control method for SADA disturbance of the large flexible sailboard satellite proposed in the embodiment can identify the flexible modal information according to the voltage data of the piezoelectric sensor according to the long-term data of the satellite in orbit, modify the control parameters of the piezoelectric actuator according to the segmented SADA specific angles and angular velocities of the identified modal data, reduce the vibration amplitude caused by the SADA disturbance by 25%, and improve the stability of the whole satellite by more than 20%.

[0108] Those skilled in the art will understand that the embodiments of the present disclosure can be provided as a method, a system or a computer program product. Therefore, the present disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] The present disclosure is described with reference to flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices generate a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The functions specified in one flow or multiple flows and / or blocks These computer program instructions can also be stored in a computer-readable memory capable of causing the computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1the function specified in the one or more blocks.

[0110] These computer program instructions can also be loaded into computer or other programmable data processing devices, so that a series of operation steps are performed on the computer or other programmable data processing devices to generate computer-implemented processes, so that the instructions executed on the computer or other programmable devices provide processes for implementing the flow Figure 1 one or more flows and / or blocks Figure 1 the function specified in the one or more blocks.

[0111] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present disclosure, but not to limit the scope of protection, although the present disclosure has been described in detail with reference to the above examples, those skilled in the art should understand: after reading the present disclosure, the skilled in the art can make various changes, modifications or equivalent replacements to the specific embodiments of the present disclosure, but these changes, modifications or equivalent replacements are all within the protection scope of the disclosed claims.

Claims

1. A flexible panel satellite active vibration control method against SADA disturbance, characterized in that, The method comprises: Step 1: install piezoelectric sensors and piezoelectric actuators symmetrically on a solar sail, collect SADA driving angles, angular velocities of fiber optic gyroscope and voltage data of piezoelectric sensors under the working condition of three-axis earth-pointing of the whole satellite body and controlled rotation tracking of the sail against the sun; Step 2: perform discrete short-time Fourier transform on the voltage data of the piezoelectric sensors to obtain amplitude spectrum and phase spectrum; Step 3: identify the frequency corresponding to the amplitude peak value according to the amplitude spectrum as the target frequency for priority suppression of active vibration control, and associate the SADA driving angle and the angular velocity of the fiber optic gyroscope corresponding to the peak value; Step 4: judge the stability of the whole satellite according to the angular velocity of the fiber optic gyroscope, and when the angular velocity exceeds a set threshold, adjust the control parameters of the piezoelectric actuators, wherein the control parameters are segmented according to the SADA driving angle and the angular velocity of the fiber optic gyroscope; The control of the piezoelectric actuators in step 4 adopts an MPPF controller, which comprises a second-order compensator and a first-order compensator, and specifically comprises: in, Indicates the first The first mode in the 1st order Second derivatives of the state variables of the second-order compensator at each control node. Indicates control damping, Indicates the control frequency. Indicates the first The first mode in the 1st order The first derivative of the state variables of the second-order compensator of each control node. Indicates the first The first mode in the 1st order The state variables of the second-order compensator of each control node. Indicates the first The measured voltage value of the piezoelectric sensor at each control node. Indicates the first The first mode in the 1st order The first derivative of the state variables of the first-order compensator of each control node. Indicates the first The first mode in the 1st order The state variables of the first-order compensator of each control node. Indicates the first The first mode in the 1st order The component of the voltage applied by the actuator of each control node. and Indicates control parameters; Step 5: iteratively execute steps 1 to 4 until the whole-satellite stability meets the index requirements.

2. The active vibration control method for SADA perturbation of a flexible panel satellite according to claim 1, wherein, The measurement equation of the piezoelectric sensor is: wherein, V is the voltage value measured by the piezoelectric sensor, C is a coefficient related to the piezoelectric material itself, is the modal shape derivative difference matrix, is the modal coordinate.

3. The active vibration control method for SADA perturbation of a flexible panel satellite according to claim 1, wherein, The calculation formula of the discrete short-time Fourier transform in step 2 is: wherein represents a complex spectral value at the i-th time frame, the j-th frequency index, represents a sample value of the original signal at the i-th time frame, represents a value of the window function at the i-th time frame, L represents a window length, i.e., a number of sample points analyzed per frame, represents a natural constant, represents an imaginary unit, k represents a frequency index value, represents an index value within a frame, N represents a number of Fourier transform points, w is a window function;​​​​ The amplitude spectrum and the phase spectrum are calculated by the following formula: wherein, denotes the amplitude spectrum, denotes the phase spectrum, denotes the real part of denotes the imaginary part of denotes the complex argument.

4. The active vibration control method for SADA perturbation of a flexible panel satellite according to claim 3, wherein, The window function of the discrete short-time Fourier transform in step 2 is the Hanning window.

5. The active vibration control method for SADA perturbation of a flexible panel satellite according to claim 1, wherein, The amplitude spectrum identification is based on the global maximum value of the amplitude spectrum, and the amplitude frequency corresponding to the global maximum value of the amplitude spectrum corresponds to the flexible modal frequency drift caused by SADA selection and serves as the target frequency of the MPPF controller.

6. The active vibration control method for SADA perturbation of a flexible panel satellite according to claim 5, wherein, The control frequency According to the amplitude peak frequency setting identified in step 3, the control parameter And According to the SADA driving angle and the angular velocity segment adjustment of the fiber optic gyroscope, the segment adjustment adopts a table lookup method, the segment region is identified based on the out-of-tolerance region, and the piezoelectric actuator control parameter setting is 0.

7. An active vibration control apparatus for a flexible panel satellite against SADA disturbance, characterized by, The device is realized based on the method of claim 1, and the device comprises: A data acquisition unit is configured to collect SADA driving angles, angular velocities of fiber optic gyroscope and voltage data of piezoelectric sensors under the working condition of three-axis earth-pointing of the whole satellite body and controlled rotation tracking of the sail against the sun; A Fourier transform unit is configured to perform discrete short-time Fourier transform on the voltage data of the piezoelectric sensors to obtain amplitude spectrum and phase spectrum; An amplitude spectrum identification unit is configured to identify the frequency corresponding to the amplitude peak value according to the amplitude spectrum as the target frequency for priority suppression of active vibration control, and associate the SADA driving angle and the angular velocity of the fiber optic gyroscope corresponding to the peak value; A judgment unit is configured to judge the stability of the whole satellite according to the angular velocity of the fiber optic gyroscope, and when the angular velocity exceeds a set threshold, adjust the control parameters of the piezoelectric actuators, wherein the control parameters are segmented according to the SADA driving angle and the angular velocity of the fiber optic gyroscope; An iteration unit is configured to iteratively execute the processes of the data acquisition unit to the judgment unit until the whole-satellite stability meets the index requirements.

8. A computer device, comprising: The device comprises a memory and a processor, and the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the active vibration control method for SADA disturbance of the flexible sail satellite according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is run by the processor to execute the steps of the flexible panel satellite active vibration control method for SADA disturbance according to any one of claims 1-6.

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