Piezoelectric stack actuator-based large shear fork type solar wing active control system

Abstract

The invention discloses a large shear fork type solar wing active control system based on a piezoelectric stack actuator. The large shear fork type solar wing active control system comprises a solar wing sailboard, an upper computer, the piezoelectric stack actuator and an MFC piezoelectric sensor, the solar wing sailboard is connected with the spacecraft base body through the piezoelectric stack actuator; the upper computer is arranged on the spacecraft base body; the MFC piezoelectric sensor is arranged on the solar wing sailboard; the piezoelectric stack actuator and the MFC piezoelectric sensor are electrically connected with the upper computer; a state observer and an LQR controller are constructed in the upper computer. The piezoelectric stack actuator is used as an active vibration suppression actuator, the MFC piezoelectric sensor is used as a vibration signal monitor, and the state observer and the LQR controller are constructed in the upper computer, so that processing and control of nonlinear vibration signals are realized, and active vibration suppression control of the large shear fork type solar wing is met; the attitude stability and the pointing precision of the spacecraft base body are effectively improved, and damage to the structure of the spacecraft base body due to long-time continuous vibration is avoided.

Description

Technical Field

[0001] This invention belongs to the field of space solar panel technology, and in particular relates to a large-scale scissor-type solar panel active control system based on a piezoelectric stacked actuator. Background Technology

[0002] With the development of aerospace technology, the increasing complexity of space missions and the need for advanced scientific payloads require substantial energy support, leading to a trend towards larger spacecraft solar panels. Because the folding and retraction ratio of traditional large solar panels limits their area, scissor-type solar panels have seen rapid development.

[0003] However, in the space environment, when the spacecraft's main body performs attitude maneuvers, pointing maneuvers, or docks with other spacecraft, large scissor solar arrays are subject to disturbances and vibrations. These vibrations are difficult to decay quickly, and prolonged, continuous vibrations can not only affect the attitude stability and pointing accuracy of the spacecraft's main body, but also, in severe cases, damage its structure and cause irreparable losses. Therefore, it is essential and imperative to actively control large scissor solar arrays to quickly suppress their micro-vibrations. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an active control system for a large scissor-type solar array based on a piezoelectric stacked actuator. The system employs a piezoelectric stacked actuator as the active vibration damping actuator and an MFC piezoelectric sensor as the vibration signal monitor. By constructing a state observer and an LQR controller in the host computer, the system achieves the processing and control of nonlinear vibration signals to meet the active vibration damping control requirements of the large scissor-type solar array. This effectively improves the attitude stability and pointing accuracy of the spacecraft substrate and avoids structural damage caused by prolonged continuous vibration.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a large-scale scissor-type solar array active control system based on a piezoelectric stack actuator, comprising a solar array panel, a host computer, a piezoelectric stack actuator, and an MFC piezoelectric sensor; the solar array panel is connected to the spacecraft substrate via the piezoelectric stack actuator; the host computer is mounted on the spacecraft substrate; the MFC piezoelectric sensor is mounted on the solar array panel; both the piezoelectric stack actuator and the MFC piezoelectric sensor are electrically connected to the host computer.

[0006] The host computer is equipped with a state observer and an LQR controller.

[0007] The solar panel includes a root rigid substrate, an end rigid substrate, and a middle flexible substrate; the MFC piezoelectric sensor is disposed on the root rigid substrate; and the middle flexible substrate is a plurality of such substrates disposed between the root rigid substrate and the end rigid substrate.

[0008] The number of MFC piezoelectric sensors is at least one, and the MFC piezoelectric sensors are fixed to the surface of the root rigid substrate by adhesive bonding.

[0009] The root rigid substrate and the end rigid substrate are not covered with solar cell modules, but only the surface of the middle flexible substrate is covered with solar cell modules; when the solar wing is in a folded storage state, the root rigid substrate and the end rigid substrate serve as the outer cover of the solar wing.

[0010] The rigid end substrate and the flexible middle substrate are connected by several pre-tensioned springs.

[0011] An end bracket is provided on the end rigid substrate; when the solar panel is in the folded storage state, the end bracket serves as a constraint and fixation device between the solar panel and the spacecraft body.

[0012] The piezoelectric stack actuator is connected to the spacecraft substrate via an adapter, and the piezoelectric stack actuator is connected to the root rigid substrate via a root support.

[0013] The beneficial effects of this invention are: The present invention relates to an active control system for a large scissor-type solar array based on a piezoelectric stacked actuator. The system uses a piezoelectric stacked actuator as the active vibration damping actuator and an MFC piezoelectric sensor as the vibration signal monitor. By constructing a state observer and an LQR controller in the host computer, the system realizes the processing and control of nonlinear vibration signals to meet the active vibration damping control requirements of the large scissor-type solar array. This effectively improves the attitude stability and pointing accuracy of the spacecraft substrate and avoids structural damage caused by long-term continuous vibration. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a large scissor-type solar array active control system based on a piezoelectric stacked actuator according to the present invention; Figure 2 The flowchart for the active vibration damping control loop is shown below. Figure 3 Flowchart for estimating the state vector for a state observer; In the figure, 1—piezoelectric stack actuator, 2—MFC piezoelectric sensor, 3—root rigid substrate, 4—end rigid substrate, 5—middle flexible substrate, 6—preload spring, 7—end support, 8—adapter, 9—root support. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0016] like Figure 1As shown, a large-scale scissor-type solar array active control system based on a piezoelectric stacked actuator includes a solar array panel, a host computer, a piezoelectric stacked actuator 1, and an MFC piezoelectric sensor 2. The solar array panel is connected to the spacecraft substrate via the piezoelectric stacked actuator 1. The host computer is mounted on the spacecraft substrate. The MFC piezoelectric sensor 2 is mounted on the solar array panel. Both the piezoelectric stacked actuator 1 and the MFC piezoelectric sensor 2 are electrically connected to the host computer.

[0017] The host computer is equipped with a state observer and an LQR controller.

[0018] In this embodiment, LabVIEW software is used as the data processing and system control software in the host computer, and a Kalman filter is used as the state observer.

[0019] The solar panel includes a root rigid substrate 3, an end rigid substrate 4, and a middle flexible substrate 5; the MFC piezoelectric sensor 2 is disposed on the root rigid substrate 3; the number of middle flexible substrates 5 is several and disposed between the root rigid substrate 3 and the end rigid substrate 4.

[0020] The number of MFC piezoelectric sensors 2 is at least one, and the MFC piezoelectric sensors 2 are fixed to the surface of the root rigid substrate 3 by adhesive bonding.

[0021] In this embodiment, the MFC piezoelectric sensor 2 uses a piezoelectric fiber diaphragm and there are three of them. The three MFC piezoelectric sensors 2 are evenly distributed on the surface of the root rigid substrate 3. The MFC piezoelectric sensors 2 are glued and fixed to the surface of the root rigid substrate 3 with epoxy resin adhesive.

[0022] The root rigid substrate 3 and the end rigid substrate 4 are not covered with solar cell modules, but only the surface of the middle flexible substrate 5 is covered with solar cell modules; when the solar wing is in a folded storage state, the root rigid substrate 3 and the end rigid substrate 4 serve as the outer cover of the solar wing.

[0023] The end rigid substrate 4 and the middle flexible substrate 5 are connected by several pre-tensioning springs 6.

[0024] An end bracket 7 is provided on the end rigid substrate 4; when the solar panel is in a folded storage state, the end bracket 7 serves as a constraint and fixation device between the solar panel and the spacecraft body.

[0025] The piezoelectric stack actuator 1 is connected to the spacecraft substrate via the adapter 8, and the piezoelectric stack actuator 1 is connected to the root rigid substrate 3 via the root support 9.

[0026] The following describes a single use of the present invention with reference to the accompanying drawings: When the solar panel changes from the folded storage state to the unfolded state, the pre-tension spring 6 can maintain a certain degree of flatness of the central flexible substrate 5 through its pre-tension force, and at the same time, it can also play a certain role in passive vibration damping.

[0027] When the spacecraft base performs attitude maneuvers, pointing maneuvers, or docks with other spacecraft, the large scissor-type solar array will be disturbed and vibrate. The vibration information will be monitored by the MFC piezoelectric sensor 2 in the first instance. The monitored vibration information is synchronously transmitted to the host computer. After processing the vibration information, the host computer sends control commands to the piezoelectric stack actuator 1. Finally, the piezoelectric stack actuator 1 performs active vibration suppression operation.

[0028] like Figure 2 As shown, the process of each active vibration suppression control cycle is as follows: the vibration information at the current moment is collected by the MFC piezoelectric sensor 2 at a frequency twice that of the control frequency. This allows for the collection of two sets of voltage data in each control cycle, thereby obtaining the Us vector synthesized from the voltage and voltage rate signals. This vector is used as the input to the nonlinear state observer. The estimated value of the current state vector X_est is calculated and used as the input to the LQR controller. Subsequently, the control voltage Ua is output to the piezoelectric stack actuator 1. Through electromechanical coupling, electrical energy is converted into control force. Finally, the control force output by the piezoelectric stack actuator 1 suppresses the vibration until the vibration is completely attenuated.

[0029] like Figure 3 As shown, the process of the state observer estimating the state vector is as follows: First, the system matrix S(X_est) is updated based on the state estimate value of the previous control cycle, and a prediction step is performed. First, the state vector X_pred is calculated, then the state estimation covariance matrix P_pred is calculated, and then the Jacobian matrix H_pred of the sensor output is calculated. Then, the update step is entered, and the aforementioned prediction step is updated based on the acquired Us signal to obtain the Kalman gain matrix L(P_pred,H_pred). Then, the updated state estimation covariance matrix P_est(L,P_pred,H_pred) and state estimate X_est(X_pred,L,Us) are obtained in sequence, which serve as the basis for the next round of control and state estimation.

[0030] The working principle of the piezoelectric stack actuator 2 is as follows: According to the positive and negative piezoelectric effects of piezoelectric ceramics, when the piezoelectric ceramics are deformed, the piezoelectric ceramics undergo charge shift and generate a potential difference, which is voltage. The larger the deformation, the larger the voltage difference. When a voltage is applied to the two ends of the piezoelectric ceramic electrodes, the piezoelectric ceramics are deformed, and the larger the voltage, the larger the deformation.

[0031] Based on the above principle, the vibration signal of the solar panel is collected by the MFC piezoelectric sensor 2, and after a series of signal processing such as amplification and filtering, it is input to the state observer. Then, the LQR controller outputs voltage and loads it onto the piezoelectric stack actuator 2, which can generate corresponding stress in the piezoelectric stack actuator 2 to affect the vibration of the solar panel, and finally achieve the purpose of active vibration suppression.

[0032] In addition, when this invention is applied on the ground, it can conduct active vibration suppression control tests on solar panels under forced vibration and free vibration under simulated weightlessness conditions. By analyzing the vibration test data and active vibration suppression control data, it can provide important references for subsequent optimization design of solar panels, optimization design of vibration suppression control, and optimization design of control algorithms.

[0033] The solutions in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the present invention are included in the scope of protection of the present invention.

Claims

1. A large-scale scissor-type solar array active control system based on a piezoelectric stack actuator, characterized in that: It includes a solar panel, a host computer, a piezoelectric stack actuator, and an MFC piezoelectric sensor; the solar panel is connected to the spacecraft substrate via the piezoelectric stack actuator; the host computer is mounted on the spacecraft substrate; the MFC piezoelectric sensor is mounted on the solar panel; both the piezoelectric stack actuator and the MFC piezoelectric sensor are electrically connected to the host computer.

2. The large-scale scissor-type solar array active control system based on a piezoelectric stack actuator according to claim 1, characterized in that: The host computer is equipped with a state observer and an LQR controller.

3. The large-scale scissor-type solar array active control system based on a piezoelectric stack actuator according to claim 1, characterized in that: The solar panel includes a root rigid substrate, an end rigid substrate, and a middle flexible substrate; the MFC piezoelectric sensor is disposed on the root rigid substrate; and the middle flexible substrate is a plurality of such substrates disposed between the root rigid substrate and the end rigid substrate.

4. The large-scale scissor-type solar array active control system based on a piezoelectric stack actuator according to claim 3, characterized in that: The number of MFC piezoelectric sensors is at least one, and the MFC piezoelectric sensors are fixed to the surface of the root rigid substrate by adhesive bonding.

5. The large-scale scissor-type solar array active control system based on a piezoelectric stack actuator according to claim 3, characterized in that: The root rigid substrate and the end rigid substrate are not covered with solar cell modules, but only the surface of the middle flexible substrate is covered with solar cell modules; when the solar wing is in a folded storage state, the root rigid substrate and the end rigid substrate serve as the outer cover of the solar wing.

6. The large-scale scissor-type solar array active control system based on a piezoelectric stack actuator according to claim 3, characterized in that: The rigid end substrate and the flexible middle substrate are connected by several pre-tensioned springs.

7. The large-scale scissor-type solar array active control system based on a piezoelectric stack actuator according to claim 3, characterized in that: An end bracket is provided on the end rigid substrate; when the solar panel is in the folded storage state, the end bracket serves as a constraint and fixation device between the solar panel and the spacecraft body.

8. The large-scale scissor-type solar array active control system based on a piezoelectric stack actuator according to claim 1, characterized in that: The piezoelectric stack actuator is connected to the spacecraft substrate via an adapter, and the piezoelectric stack actuator is connected to the root rigid substrate via a root support.

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