A distributed angular vibration active control system and method

Abstract

The application discloses a kind of distributed angular vibration active control system and method, wherein the system includes: acquisition module, control module and output module;Wherein the acquisition module: the vibration signal of different positions of target structure is collected, and vibration signal is transmitted to the control module;The control module: receive vibration signal, control signal is generated according to vibration signal, and control signal is transmitted to the output module;The output module: receive control signal, and control signal is converted into actual control force and acts on target structure, realizes angular vibration control.The application can effectively inhibit the angular vibration in the working process of spacecraft, and guarantee pointing accuracy and imaging quality.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft vibration control technology, and particularly relates to a distributed angular vibration active control system and method. Background Technology

[0002] In recent years, the rapid development of space remote sensing technology and the continuous improvement of space exploration accuracy have placed increasingly higher demands on the resolution of space optical remote sensors. The increase in payload aperture has made large-flexibility structures the main direction of development for modern space optical remote sensors. Due to the relative motion between the spacecraft and the observed object, orbital perturbations caused by uneven gravity generated by the orbit, solar radiation pressure, etc., changes in the spacecraft's attitude and orbit, and micro-vibrations of the spacecraft, relative motion between the observed target and the detector will occur within the exposure time of the imaging detector, resulting in image blurring, known as image shift. After compensation for the relative motion between the spacecraft and the observed object by the pointing and tracking system, the main factors causing image shift are changes in spacecraft attitude, vibration, and impact, among which the influence of the principal axis angular vibration of the optical system is particularly significant.

[0003] Because space telescopes have relatively large focal lengths, they exhibit an "optical lever effect." Even extremely small angular vibrations in the optical system can lead to significant image blurring or distortion. In low Earth orbit, a 1″ movement of the "optical lever" can cause a 2.4m deviation from the observed target; the situation is even more severe in high Earth orbits. Since this image shift is irregular and its magnitude varies randomly, it cannot be calculated from flight data and significantly impacts image quality, resulting in a marked decrease in image resolution—unacceptable for high-resolution satellites. Therefore, it is necessary to control the angular vibrations of the spacecraft. This process presents the following challenges:

[0004] 1. Current research on vibration control mainly focuses on linear vibration. When angular vibration needs to be controlled, it is usually done by decoupling and controlling six-free disturbance simultaneously, which increases the complexity of the control process. Moreover, considering various errors in the structure, coupling still exists.

[0005] 2. Large-scale optical systems have large spatial dimensions and complex internal structures. Methods that only control micro-vibrations at a certain point or in a certain area cannot meet the requirements of high-resolution imaging. Traditional platform-type and truss-type micro-vibration control structures have specific installation space requirements and mainly act on the disturbance of the local overall structure. They cannot control the micro-vibrations inside the structure and are no longer suitable for the characteristics of large-scale space optical systems with multiple disturbance sources and multiple sub-imaging units.

[0006] 3. When performing multi-point vibration control on large spacecraft, in order to achieve better control results, it is necessary to deploy as many control points as possible. If a centralized controller is used, a large amount of control data will be generated, so the control effect is limited by the computing power of the onboard computer. Summary of the Invention

[0007] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a distributed angular vibration active control system and method that can effectively suppress angular vibration during spacecraft operation and ensure pointing accuracy and imaging quality.

[0008] The objective of this invention is achieved through the following technical solution: a distributed angular vibration active control system, comprising: a data acquisition module, a control module, and an output module; wherein, the data acquisition module: acquires vibration signals at different locations of the target structure and transmits the vibration signals to the control module; the control module: receives the vibration signals, generates control signals based on the vibration signals, and transmits the control signals to the output module; the output module: receives the control signals, converts the control signals into actual control forces acting on the target structure, thereby realizing angular vibration control.

[0009] The aforementioned distributed angular vibration active control system further includes: multiple subsystem acquisition modules; wherein each subsystem acquisition module acquires the vibration signal of the attached vibration absorption unit corresponding to each subsystem, and transmits the vibration signal of the attached vibration absorption unit corresponding to each subsystem to the acquisition module.

[0010] A distributed angular vibration active control method includes: establishing a structural dynamics model based on the finite element model and modal information of the target structure; establishing a closed-loop control model based on the structural dynamics model, using control parameters as input and the response of the target structure at a preset position as output, combined with a control law; optimizing the input control parameters according to a preset optimization objective based on the closed-loop control model to obtain initial control parameters; installing a single attached vibration absorption unit on a test fixture for single-machine performance testing, activating vibration disturbance and performing single-machine closed-loop control testing; if the vibration control is effective, the attached vibration absorption unit is considered to be ready for installation; if the vibration control is ineffective, the attached vibration absorption unit is discarded; installing multiple attached vibration absorption units ready for installation at vibration control points on the target structure, inputting the initial control parameters to the attached vibration absorption units ready for installation, and performing angular vibration control on the target structure to obtain vibration control results.

[0011] In the above-mentioned distributed angular vibration active control method, the modal information includes the natural frequency matrix, the modal input matrix, and the modal output matrix.

[0012] In the above-mentioned distributed angular vibration active control method, the structural dynamics model is obtained through the following formula:

[0013]

[0014] y = [cm0]x

[0015] Where Λ is the natural frequency matrix, bm Let c be the modal input matrix. m For modal output matrix, Let be the first derivative of the system state parameters with respect to time, Z be the system damping matrix, x be the system state parameters, u be the input vector, and y be the output vector.

[0016] In the above distributed angular vibration active control method, x is:

[0017]

[0018] Where, q m For modal coordinates, This is the first derivative of the modal coordinates with respect to time.

[0019] In the above-mentioned active control method for distributed angular vibration, during testing, a single attached vibration absorption unit and the vibration source are simultaneously installed on the test fixture.

[0020] In the above-mentioned distributed angular vibration active control method, another attached vibration absorption unit is used as the disturbance source. The attached vibration absorption unit, which is the disturbance source, does not collect data; the disturbance source actively acts according to the settings to generate disturbance.

[0021] In the above-mentioned distributed angular vibration active control method, the attached vibration absorption unit that starts the test first enters the data acquisition mode, and then turns on the vibration absorption mode. The acquired data is observed and analyzed. If the acquired data is normal and the acquired data decays after the vibration absorption mode is turned on, the vibration control is considered to be effective. If the data cannot be acquired normally, or the data does not change significantly after the vibration absorption mode is turned on, the vibration control is considered to be ineffective.

[0022] An electronic device includes: a memory for storing computer-readable instructions; and a processor for executing the computer-readable instructions to perform a distributed angular vibration active control method.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The present invention uses distributed attached vibration absorption units to input control force. Each unit is an independent control system, which is naturally decoupled and eliminates the coupling problem of control input. The overall angular vibration control design can be discretized into vibration control design for each unit, which reduces the control difficulty.

[0025] (2) The main actuator of the present invention consists of multiple vibration absorption units, which are relatively small in size to the target structure and can be installed inside the target structure to achieve precise control of the installation point, greatly improving the flexibility of the angular vibration control scheme.

[0026] (3) The closed-loop operation of the distributed control of the present invention does not depend on the on-board computer and is completed independently by each vibration absorption unit. Theoretically, it is not constrained by computing power and can execute more complex control algorithms, thus significantly improving the vibration control effect. Attached Figure Description

[0027] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0028] Figure 1 This is a structural block diagram of the distributed angular vibration collaborative control system provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the adsorption unit provided in an embodiment of the present invention disposed on the target structure;

[0030] Figure 3 This is a flowchart illustrating the implementation of the distributed angular vibration collaborative control method provided in this embodiment of the invention.

[0031] Figure 4 This is a simulation result diagram provided by an embodiment of the present invention. Detailed Implementation

[0032] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] Figure 1 This is a structural block diagram of the distributed angular vibration cooperative control system provided in an embodiment of the present invention. Figure 1 As shown, the distributed angular vibration active control system includes: a data acquisition module, a control module, and an output module; wherein, the data acquisition module: acquires vibration signals at different locations of the target structure and transmits the vibration signals to the control module; the control module: receives the vibration signals, generates control signals based on the vibration signals, and transmits the control signals to the output module; the output module: receives the control signals, converts the control signals into actual control forces acting on the target structure, and realizes angular vibration control.

[0034] The distributed angular vibration active control system also includes an offline simulation and optimization module for simulation and optimization.

[0035] The distributed angular vibration active control system also includes multiple subsystem acquisition modules; wherein, each subsystem acquisition module acquires the vibration signal of the attached vibration absorption unit corresponding to each subsystem, and transmits the vibration signal of the attached vibration absorption unit corresponding to each subsystem to the acquisition module.

[0036] The system comprises multiple subsystems, each consisting of attached vibration-absorbing units. Each subsystem has an independent acquisition module, control module, and output module, enabling decentralized independent control while also working collaboratively with other modules of the main system.

[0037] The attached vibration absorption unit used in this system has the following features: (1) It is small in size relative to the target structure, flexible in installation, and can be attached to any permissible position; (2) It has a self-acquisition closed-loop control function, which can directly generate control force based on the signal collected at the installation position; (3) The parameters are adjustable, and its internal structural characteristics and algorithm can be adjusted as needed.

[0038] like Figure 1 As shown, the distributed angular vibration active control system is used to control angular vibrations perpendicular to the pointing direction in a target structure, maintaining directional stability. The system includes an offline simulation optimization module, a data acquisition module, a control module, and an output module. The system comprises multiple subsystems, primarily consisting of attached vibration-absorbing units. These units are relatively small compared to the target structure, offer flexible installation, and can be attached to any permissible location. They possess self-acquisition closed-loop control capabilities, directly generating control force based on signals acquired at their installation locations. Furthermore, their internal structural characteristics and algorithms can be adjusted as needed. The data acquisition functions of each vibration-absorbing unit, along with other acquisition devices installed on the target structure (not shown in the figure), together constitute the data acquisition module of the distributed angular vibration active control system, providing the system with analytical data and the necessary information for control. The control loops within each vibration-absorbing unit collectively form the system's control module. Typically, each unit operates autonomously after parameter settings, but the system host can also directly control each unit, modifying parameters online or directly controlling the output.

[0039] Figure 2 The sub-boxes inside each vibration absorption unit represent the control algorithm used by the vibration absorption unit. This control algorithm can be modified as needed, and includes an LMS-based vibration control algorithm, as shown below:

[0040]

[0041] an+1 = an + μe(n)sin(wdn)

[0042] bn+1=bn+μe(n)cos(wan)

[0043] n is the sampling sequence, e(n) is the error signal acquired by the vibration absorption unit, y(n) is the output of the vibration absorption unit, and w d To control the frequency, a n b n The weights are μ, the iteration coefficients are α, and μ is the weight coefficient. These are system-related parameters.

[0044] The target structure is identified or modeled using finite element methods to obtain modal information, which is then input into the offline simulation optimization module. This allows for the optimization of control parameters and the improvement of control performance.

[0045] This embodiment also provides a distributed active control method for angular vibration, the method comprising:

[0046] Based on the finite element model and modal information of the target structure, a structural dynamics model is established;

[0047] Based on the structural dynamics model, a closed-loop control model is established by taking control parameters as input, the response of the target structure at a preset position as output, and combining the control law.

[0048] Based on the closed-loop control model, the input control parameters are optimized according to the preset optimization objective to obtain the initial control parameters;

[0049] A single attached vibration absorption unit is installed on a test fixture for single-unit performance testing. Vibration disturbance is activated and single-unit closed-loop control testing is performed. If the vibration control is effective, the attached vibration absorption unit is considered to be ready for installation; if the vibration control is ineffective, the attached vibration absorption unit is discarded.

[0050] Multiple attached vibration absorption units in the installation-ready state are installed at vibration control points on the target structure. Initial control parameters are input to the attached vibration absorption units in the installation-ready state, and angular vibration control is performed on the target structure to obtain vibration control results.

[0051] Modal information includes the natural frequency matrix, the modal input matrix, and the modal output matrix.

[0052] The structural dynamics model is obtained through the following formula:

[0053]

[0054] y = [c m 0]x;

[0055] Where Λ is the natural frequency matrix, b m Let c be the modal input matrix. m For modal output matrix, Let be the first derivative of the system state parameters with respect to time, Z be the system damping matrix, x be the system state parameters, u be the input vector, and y be the output vector.

[0056]

[0057] Where, q m For modal coordinates, This is the first derivative of the modal coordinates with respect to time.

[0058] The implementation steps of the distributed angular vibration active control method are as follows: Figure 3 As shown.

[0059] (1) Establish a finite element model for the target structure, obtain modal information, and establish a structural dynamics model to describe the input-output relationship of the system.

[0060] The modal information of the target structure includes: the r-th order mode shape matrix φ = [φ1, φ2, ..., φ r ], corresponding to the natural frequency matrix Λ=diag{λ1 2 ,λ2 2 ,…,λ r 2}, modal input matrix b m and modal output matrix c m ;

[0061] The established structural dynamics model is usually a state-space model, in the following form:

[0062]

[0063] y = [cm0]x

[0064] q m For modal coordinates, u and y are the system input and output, respectively;

[0065] (2) Based on the structural dynamics model in step (1), a closed-loop control model is established according to the input and output points of the actual structure and the control law. The input of the control model is the control parameters, and the output is the response at the location of interest.

[0066] Assuming the system has I output points, with D disturbance points and A actuator mounting points; and O output points, with S sensor mounting points, then:

[0067] u is the input force vector, including the vibration input u D and control input u A ,satisfy:

[0068] u(6I×1))=uD+uA

[0069]

[0070] M DI M D These are the disturbance force input matrix and the disturbance force, M, respectively. AI M AM M C These are the outputs of the control input matrix, the control mounting matrix, and the control signal generation module, respectively.

[0071] y is the output displacement vector, which includes the acquisition vector y C ,satisfy:

[0072]

[0073] M SM M SO These are the acquisition installation matrix and the acquisition output matrix, respectively.

[0074] According to the control law, through y C Generate M C This leads to u A This enables closed-loop control.

[0075] The established closed-loop control model includes a system model module, a disturbance input module, a response extraction module, a control parameter input module, a parameter allocation module, a control signal generation module, and a system output module.

[0076] The system model module takes two inputs: a disturbance input module and a control signal generation module, corresponding to the system's disturbance and control force inputs. The outputs are the responses from multiple control channels, which are then sent to the response extraction module and the system output module. The disturbance input module can generate the corresponding disturbance force according to a planned time function, or it can load actually acquired disturbance force data. The response extraction module selects the reference signal from all outputs to generate the control force, while the system output module displays the response of the target structure of interest.

[0077] The control parameter input module provides control parameters for all control channels. The parameter allocation module summarizes all response signals and control parameters and groups them by channel. Each group contains the response and control parameters corresponding to that control channel and outputs them to the control signal generation module. The control signal generation module contains a number of control sub-modules equal to the number of control channels. Each sub-module corresponds to one control channel. Based on the input response and control parameters, it generates control force according to the corresponding control law and inputs it to the system model module.

[0078] In a collaborative control system, the set of error signals e(n) collected by each vibration absorption unit is the collection vector y. C The set of output signals y(n) is the control input u.A Control parameter w d μ, α These are introduced through the control parameter input module.

[0079] (3) Based on the control model in step (2), design the optimization target and optimize the control algorithm parameters through the intelligent algorithm. The optimization result is used as the initial control parameter. Both the optimization target and the intelligent algorithm can be adjusted according to actual needs. The intelligent algorithm outputs the control parameters to the closed-loop control model to calculate the optimization target and iteratively updates the control parameters.

[0080] (4) Install a single vibration absorption unit and a vibration disturbance source on the test fixture at the same time. The vibration disturbance source can be another vibration absorption unit. At this time, the vibration absorption unit, which is the vibration disturbance source, will not collect data and generate control signals. Instead, it will actively act according to the settings to generate stable vibration disturbance. The vibration absorption unit that starts the test first enters the data acquisition mode, and then turns on the vibration absorption mode. Observe and analyze the data it collects. If the data acquisition is normal and the data shows significant attenuation after the vibration absorption mode is turned on, the vibration control is considered to be effective. If the data cannot be collected normally, or the data does not change significantly after the vibration absorption mode is turned on, the vibration control is considered to be ineffective.

[0081] If vibration control is effective, the vibration absorption unit is considered ready for installation; if vibration control is ineffective, the unit is discarded.

[0082] (5) Install the multiple attached vibration absorption units in the installation state obtained in step (4) at multiple vibration control points on the target structure, and input the initial control parameters obtained in step (3) to obtain a closed-loop control system. Start the control system to realize distributed angular vibration control of the target structure. Figure 1 The image shows a typical implementation scenario;

[0083] (6) Record and analyze the vibration control results. If the control results do not meet the specific index requirements, the target structure is identified through the test system. The structural dynamics model in step (1) is corrected according to the identification results, and the control algorithm parameters are optimized again. The control parameters in step (5) are updated according to the results.

[0084] Both the optimization objective and the intelligent algorithm can be adjusted according to actual needs. The intelligent algorithm outputs control parameters to the closed-loop control model to calculate the optimization objective and iteratively updates the control parameters.

[0085] A 10-second simulation analysis was conducted. The system model in the simulation was obtained by finite element modeling and modal analysis of the actual model. The system's vibration disturbance was a fixed-frequency disturbance. The angular vibration index of interest was calculated in real time, and vibration control was performed on 12 target points. Vibration control was initiated at the 5th second. Figure 4The results show that this embodiment can simultaneously control the vibration of multiple channels and ultimately suppress angular vibration.

[0086] This embodiment also provides an electronic device, including: a memory for storing computer-readable instructions; and a processor for running the computer-readable instructions to execute a distributed angular vibration active control method.

[0087] In this embodiment, multiple attached vibration-absorbing units are installed at different locations on the spacecraft structure, and the installation points are controlled independently to form a distributed control system. At the same time, by coordinating the various vibration-absorbing units, the overall angular vibration of the spacecraft is suppressed, thus jointly ensuring the pointing accuracy and imaging quality of the spacecraft.

[0088] This embodiment uses distributed, attached vibration-absorbing units for control force input. Each unit is an independent control system, naturally decoupled, eliminating the coupling problem of control input. The overall angular vibration control design can be discretized into vibration control designs for each unit, reducing the control difficulty. The main actuators in this embodiment are multiple vibration-absorbing units, which are relatively small in size compared to the target structure and can be installed inside the target structure to achieve precise control of the installation points, greatly improving the flexibility of the angular vibration control scheme. The closed-loop calculation of the distributed control in this embodiment does not rely on the onboard computer and is completed independently by each vibration-absorbing unit. Theoretically, it is not constrained by computing power and can execute more complex control algorithms, thus significantly improving the vibration control effect.

[0089] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A distributed angular vibration active control method, characterized in that... include: Based on the finite element model and modal information of the target structure, a structural dynamics model is established; Based on the structural dynamics model, a closed-loop control model is established by taking control parameters as input, the response of the target structure at a preset position as output, and combining the control law. Based on the closed-loop control model, the input control parameters are optimized according to the preset optimization objective to obtain the initial control parameters; A single attached vibration absorption unit is installed on a test fixture for single-unit performance testing. Vibration disturbance is activated and single-unit closed-loop control testing is performed. If the vibration control is effective, the attached vibration absorption unit is considered to be ready for installation; if the vibration control is ineffective, the attached vibration absorption unit is discarded. Multiple attached vibration absorption units in the installation state are installed at vibration control points on the target structure. Initial control parameters are input to the attached vibration absorption units in the installation state, and angular vibration control is performed on the target structure to obtain vibration control results. If the control results do not meet the specific index requirements, the target structure is identified through the testing system. The structural dynamics model is corrected according to the identification results, and the control algorithm parameters are optimized again. The control parameters are updated according to the results. Modal information includes the natural frequency matrix, modal input matrix, and modal output matrix; The structural dynamics model is obtained through the following formula: ； ； in, The inherent frequency matrix, The modal input matrix, For modal output matrix, The first derivative of the system state parameters with respect to time. For the system damping array, These are system state parameters. For the input vector, This is the output vector; for: ； in, For modal coordinates, The first derivative of the modal coordinates with respect to time; During testing, a single attached vibration absorption unit and the vibration source are simultaneously installed on the test fixture; Another attached vibration absorption unit is used as the vibration disturbance source. The attached vibration absorption unit used as the vibration disturbance source will not collect data; the vibration disturbance source will actively act according to the settings to generate vibration disturbance. The attached vibration absorption unit that starts the test first enters the data acquisition mode, and then turns on the vibration absorption mode. The acquired data is observed and analyzed. If the acquired data is normal and the acquired data decays after the vibration absorption mode is turned on, the vibration control is considered to be effective. If the data cannot be acquired normally, or the data does not change significantly after the vibration absorption mode is turned on, the vibration control is considered to be ineffective.

2. A distributed angular vibration active control system, applied to the method of claim 1, characterized in that... include: The module consists of a data acquisition module, a control module, and an output module; among which, The acquisition module acquires vibration signals from different locations on the target structure and transmits the vibration signals to the control module. The control module receives vibration signals, generates control signals based on the vibration signals, and transmits the control signals to the output module. The output module receives control signals and converts them into actual control forces that act on the target structure to achieve angular vibration control. It also includes: multiple subsystem acquisition modules; among which, Each subsystem acquisition module acquires the vibration signal of the attached vibration absorption unit corresponding to each subsystem, and transmits the vibration signal of the attached vibration absorption unit corresponding to each subsystem to the acquisition module; The sub-boxes inside each vibration absorption unit represent the control algorithm used by the vibration absorption unit. This control algorithm can be modified as needed, and includes an LMS-based vibration control algorithm, as shown below: in, For sampling sequences, The error signal collected by the vibration absorption unit. For the output of the vibration damping unit, To control the frequency, , For weighting coefficients, For iteration coefficients, , These are system-related parameters.

3. An electronic device, characterized in that, include: Memory: Used to store computer-readable instructions; and Processor: configured to execute the computer-readable instructions and perform the method as described in claim 1.

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