Magnetic suspension test system for satellite attitude verification and control method thereof

Abstract

The invention discloses a magnetic suspension test system for satellite attitude verification and a control method thereof, and relates to the technical field of equipment testing, a first electromagnet of the system is fixed at the top end of a frame as a controllable magnetic field source, and a through hole coaxial with a magnetic axis of a connector is formed in the lower end of the connector to form a guide channel. The connecting rod penetrates through the through hole and is axially limited and protected by the first limiting part and the second limiting part, the bottom end of the connecting rod is connected with a satellite to be verified, the permanent magnet is fixed at the top end of the connecting rod and is coaxially aligned with the electromagnet, and controllable magnetic attraction force is generated after electrification to counteract the gravity of the dynamic subsystem to establish non-contact suspension support. The laser displacement sensor is aligned with the second limiting part to measure distance information, the suspension state is judged according to distance changes, electromagnet current is fed back and adjusted, and suspension height closed-loop control is achieved. The system is compact in structure and clear in control logic, obviously reduces the influence of mechanical friction and assembly errors, and is suitable for repeatable ground verification of micro-nano satellite attitude control in a vacuum environment.

Description

Technical Field

[0001] This specification relates to the field of equipment testing technology, and more specifically, this application relates to a magnetic levitation testing system for satellite attitude verification and its control method. Background Technology

[0002] In recent years, microsatellites and nanosatellites have evolved from early teaching and verification platforms into an important type of spacecraft undertaking complex tasks such as remote sensing, communication, and navigation due to their advantages of low development cost, short development cycle, and flexible deployment. As the complexity and accuracy requirements of missions continue to increase, the requirements for attitude control accuracy and stability of microsatellites and nanosatellites have significantly increased, and attitude control performance is directly related to mission execution results.

[0003] However, compared to large spacecraft, microsatellites and nanosatellites are characterized by their small mass and low moment of inertia. Even minute torques generated by any moving component on the satellite can have a significant dynamic coupling effect with the satellite itself, leading to amplified attitude disturbances or even system instability. Therefore, conducting high-fidelity ground-based attitude control verification before launch is crucial for identifying potential coupling problems and verifying the performance of control algorithms and actuators. An ideal ground verification environment should reproduce the satellite's near-frictionless, microgravity-free dynamic state in orbit as closely as possible. However, under ground conditions, any supporting or constraining structure will inevitably introduce friction, damping, or additional torques, thus affecting the accuracy of the verification results.

[0004] Existing ground-based verification methods for satellite attitude control mainly include digital simulation and physical simulation experiments. Digital simulation relies on mathematical models and computer simulations, making it difficult to fully reflect the actual physical coupling process. Physical simulations commonly use air-floating platforms and magnetic levitation platforms, which can reduce the impact of friction to some extent. However, air-floating platforms rely on compressed gas to form an air film, making them difficult to operate in a vacuum environment, and the systems are complex and costly. While magnetic levitation platforms can operate under vacuum conditions, existing solutions generally suffer from problems such as residual mechanical contact, high requirements for processing and assembly precision, high cost, and insufficient versatility and repeatability. Some systems also struggle to support the verification of closed-loop attitude control by the satellite under test through its own actuators.

[0005] Therefore, there is an urgent need for a ground attitude verification system for micro and nano satellites that has a relatively simple structure, no or low mechanical friction, can operate in a vacuum environment, and has good versatility and repeatability, so as to achieve high-fidelity ground verification of the attitude dynamics and control process of micro and nano satellites. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] In a first aspect, the present invention proposes a magnetic levitation test system for satellite attitude verification, comprising: Framework body, The first electromagnet is fixedly connected to the top of the frame body. A connecting body is fixedly connected to the first electromagnet. A through hole is provided at the bottom end of the connecting body, and the axis of the through hole is correspondingly set with the magnetic axis of the first electromagnet. The connecting rod includes a first limiting part and a second limiting part. The connecting rod passes through the through hole of the connecting body. The first limiting part and the second limiting part are located at the two ends of the through hole, respectively. The bottom end of the connecting rod is connected to the satellite to be verified. A permanent magnet is fixedly connected to the top of the connecting rod, and the magnetic axis of the permanent magnet is arranged corresponding to the axis of the connecting rod. A laser displacement sensor is fixedly connected to the frame body and is used to measure the distance information between the laser displacement sensor and the second limiting part.

[0008] In one feasible implementation, the aforementioned satellite attitude verification magnetic levitation test system further includes: A horizontal magnetic field compensation coil group is connected to the frame body. The horizontal magnetic field compensation coil group includes at least two sets of horizontal magnetic field compensation coils. The center line of the horizontal magnetic field compensation coils is located between the top of the first electromagnet and the top of the permanent magnet.

[0009] In one feasible implementation, the aforementioned satellite attitude verification magnetic levitation test system further includes: The damping disc is connected to the connecting rod near its bottom end. The second electromagnet and the third electromagnet are connected to the frame body and are symmetrically arranged about the axis of the damping disc.

[0010] In one feasible implementation, the aforementioned satellite attitude verification magnetic levitation test system further includes: A high-speed camera, which is fixed on the frame body.

[0011] In one feasible implementation, the measuring component of the laser displacement sensor is correspondingly disposed with the second limiting part, which is frustum-shaped.

[0012] Secondly, the present invention proposes a control method for the magnetic levitation test system for satellite attitude verification described in the first aspect, comprising: After the satellite to be verified completes the test preparation work, the first electromagnet is energized and the distance information between the laser displacement sensor and the second limiting part is obtained. Based on the aforementioned distance information, the current information of the first electromagnet is controlled to control the attractive force between the first electromagnet and the permanent magnet, so that the distance information between the first electromagnet and the permanent magnet is within a preset distance range.

[0013] In one feasible implementation, the control of the energizing current information of the first electromagnet based on the distance information includes: The distance information obtained above is compared with the preset distance information corresponding to the preset target suspension distance to obtain the distance deviation; A suspension state error signal is constructed based on the aforementioned distance deviation, and a corresponding current adjustment amount is generated based on the aforementioned error signal. The current adjustment amount is superimposed on the initial energizing current of the first electromagnet to serve as the energizing current information of the first electromagnet, so as to dynamically adjust the magnetic field strength generated by the first electromagnet.

[0014] In one feasible implementation, when the second limiting part is frustum-shaped, the current adjustment amount is calculated based on the following formula:

[0015]

[0016] Where k is the current sampling time; This is the total output of the controller, i.e., the PWM value applied to the electromagnet; It is the basic feedforward control quantity used to balance the gravity of the levitation vehicle; This represents the current position error, which is the difference between the measured value and the set value. This represents the measured value from the laser displacement sensor at the current moment. This is the measured value of the laser displacement sensor at the previous moment; This is the velocity value at the current moment after undergoing a first-order low-pass filter. This is the velocity value after first-order low-pass filtering at the previous moment; These are the velocity filter coefficients; These are the proportional, integral, and differential gain coefficients, respectively.

[0017] In one feasible implementation, where the aforementioned magnetic levitation test system for satellite attitude verification further includes a horizontal magnetic field compensation coil group, the control method further includes: After the first electromagnet and the permanent magnet form a magnetic levitation state, the horizontal magnetic field compensation coil group is energized to generate a compensation magnetic field in the horizontal direction. The attitude oscillation characteristic information of the satellite to be verified in a suspended state is obtained, wherein the attitude oscillation characteristic information includes oscillation period information; Based on the above attitude oscillation characteristic information, the current ratio and current amplitude of each compensation coil in the above horizontal magnetic field compensation coil group are adjusted to change the direction and intensity of the above compensation magnetic field. By iteratively adjusting the direction and intensity of the aforementioned compensating magnetic field, the attitude oscillation characteristics of the satellite to be verified are made to meet the preset stability conditions, thereby reducing the impact of the magnetic field inhomogeneity in the horizontal direction of the magnetic levitation system on attitude verification.

[0018] In one feasible implementation, where the above-described magnetic levitation test system for satellite attitude verification further includes a damping disk, a second electromagnet, and a third electromagnet, the method further includes: After completing an attitude verification test, the rotational state information of the satellite to be verified in magnetic levitation state was obtained; When it is determined that the rotation state of the satellite to be verified does not meet the preset reset conditions, the second electromagnet and the third electromagnet are energized to generate a magnetic field at the damping disk. The electromagnetic damping effect generated by the movement of the damping disk in the magnetic field is used to attenuate the rotational state of the connecting rod and the satellite to be verified. The calculation formula for the electromagnetic damping effect is as follows:

[0019] Where F represents magnetic force. Remanence is an intrinsic property of the material; The relative permeability of the material; l is the air gap length; l is the magnet length; Let A be the vacuum permeability, and A be the area of ​​the magnet. When it is determined that the rotation state of the satellite to be verified meets the preset reset conditions, the second electromagnet and the third electromagnet are de-energized to release the electromagnetic damping effect on the damping disk, thereby enabling the magnetic levitation test system to enter the next attitude verification test state.

[0020] In summary, compared to ground-based satellite attitude verification schemes that rely on air buoyancy or complex multi-degree-of-freedom magnetic levitation structures in related technologies, the magnetic levitation test system for satellite attitude verification proposed in this invention offers significant improvements in structural simplification, environmental adaptability, friction suppression capability, and test repeatability. First, the invention utilizes a first electromagnet and a permanent magnet to form an axial magnetic attraction levitation structure along the same magnetic axis, directly counteracting the gravity of the levitation subsystem with electromagnetic force, thus achieving non-contact support for the satellite in the vertical direction. Compared to magnetic levitation platform schemes in related technologies that still involve mechanical bearings, ball bearings, or auxiliary supports, this structure does not rely on any mechanical contact components during levitation operation, fundamentally eliminating problems such as mechanical friction, gap impact, and lubrication failure under vacuum conditions. This makes the attitude motion process closer to the near-frictionless dynamic environment of satellite operation in orbit, significantly improving the consistency between ground verification results and actual in-orbit conditions. Second, this invention adopts a magnetic levitation technical approach, focusing the verification objective on the most critical and fundamental dynamics and control issues in micro / nano satellite attitude control. Compared to the extremely high requirements for machining accuracy, assembly concentricity, number of sensors, and complexity of control algorithms in five- or three-degree-of-freedom magnetic levitation platforms in related technologies, this embodiment significantly reduces the system's dependence on spatial installation accuracy and multi-sensor collaborative calculation through a single magnetic axis alignment structure and through-hole guiding design. This makes the system structure more compact, the control logic clearer, and the implementation difficulty of the processor and control algorithm significantly reduced, thereby improving the system's engineering feasibility and reliability. In this invention, the through-hole of the connecting body is coaxially set with the magnetic axis, and in conjunction with the axial limiting structure of the connecting rod, it effectively constrains and protects the axial travel of the moving subsystem while ensuring its levitation degree of freedom. This combination of magnetic levitation and passive limiting design makes the system safer during startup, debugging, and abnormal operating conditions, avoiding the structural collision risk caused by control instability or overshoot during the adjustment process of traditional magnetic levitation systems, and facilitating the conduct of multiple rounds of long-term repetitive tests. This invention uses a laser displacement sensor to perform non-contact real-time measurement of the levitation height, and uses this displacement information as feedback for adjusting the magnetic attraction force, realizing closed-loop control of the levitation height. This magnetic adjustment method based on position feedback allows for quantitative determination and fine-tuning of the levitation state, laying the foundation for introducing the satellite's own attitude actuators into experiments and conducting real closed-loop attitude control verification. It overcomes the problem in some prior art solutions where the test object can only passively receive external torque and cannot reflect the actual control process. Because the invention has a simple overall structure, few components, and relatively moderate requirements for processing precision and assembly conditions, and does not rely on high-pressure gas sources or ultra-low temperature superconducting environments, it is easy to implement and maintain under vacuum conditions, and its testing cost is significantly lower than that of air-bearing platforms and superconducting magnetic levitation schemes.Meanwhile, the structure is highly adaptable to changes in the size and mass of the satellite under test, with satellite mass ranging from 0.1 to 100 kg. The suspension configuration under different load conditions can be completed simply by adjusting the electromagnet current parameters. Therefore, it has strong versatility and repeatability, making it particularly suitable for the engineering ground verification of micro-nano satellite attitude control algorithms and systems.

[0021] Other advantages, objectives and features of this application will be apparent in part from the description which follows, and in part from what those skilled in the art will understand through study and practice of this application. Attached Figure Description

[0022] 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 this specification. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the planar structure of a magnetic levitation test system for satellite attitude verification is provided in an embodiment of this application. Figure 2 A three-dimensional structural schematic diagram of a magnetic levitation test system for satellite attitude verification is provided in this application embodiment; Figure 3 This is a schematic diagram of a control method provided in an embodiment of this application; Figure 4 This is a schematic diagram illustrating the ranging principle of a laser displacement sensor provided in an embodiment of this application; Figure 5 This application provides a schematic diagram of a laser displacement sensor ranging process in accordance with an embodiment of the present application. Figure 6 This is a schematic diagram illustrating the working principle of a horizontal magnetic field compensation coil group according to an embodiment of this application; Figure 1 and Figure 2 The correspondence between the reference numerals and labels in the attached figures is as follows: 101—Frame body, 102—First electromagnet, 103—Connector, 104—Connecting rod, 1041—First limiting part, 1042—Second limiting part, 105—Permanent magnet, 106—Laser displacement sensor, 107—Horizontal magnetic field compensation coil group, 108—Damping disk, 109—Second electromagnet, 110—Third electromagnet, 20—Satellite to be verified. Detailed Implementation

[0023] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The technical solutions of the embodiments of this application will now be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0024] Please see Figure 1 and Figure 2 , Figure 1 This application provides a structural schematic diagram of a magnetic levitation test system for satellite attitude verification, as proposed in this invention. Figure 2 A three-dimensional structural diagram of a magnetic levitation test system for satellite attitude verification is provided in this application embodiment. The system includes: Frame body 101, The first electromagnet 102 is fixedly connected to the top end of the frame body 101. Connector 103 is fixedly connected to the first electromagnet 102. The bottom end of the connector 103 is provided with a through hole, and the axis of the through hole is correspondingly set with the magnetic axis of the first electromagnet 102. The connecting rod 104 includes a first limiting part 1041 and a second limiting part 1042. The connecting rod 104 passes through the through hole of the connecting body. The first limiting part 1041 and the second limiting part 1042 are respectively located at both ends of the through hole. The bottom end of the connecting rod 104 is connected to the satellite 20 to be verified. A permanent magnet 105 is fixedly connected to the top end of the connecting rod 104, and the magnetic axis of the permanent magnet 105 is correspondingly arranged with the axis of the connecting rod. A laser displacement sensor 106 is fixedly connected to the frame body 101 and is used to measure the distance information between itself and the second limiting part 1042.

[0025] For example, this embodiment provides a core structure for a magnetic levitation test system for satellite attitude verification. The frame body 101 serves as the overall support and installation reference. A first electromagnet 102 is fixedly installed at the top of the frame body 101, so that the first electromagnet 102 maintains a stable spatial position during the test, thereby serving as a controllable magnetic field source to provide an adjustable magnetic attraction force for the levitation system.

[0026] A connecting body 103 is fixedly connected to the lower part of the first electromagnet 102. A through hole is provided at the bottom end of the connecting body 103. The axis of the through hole corresponds to the magnetic axis of the first electromagnet 102, thereby naturally forming a guide channel along the magnetic axis. This ensures the center alignment of subsequent moving parts and reduces the risk of eccentricity and swaying during the assembly and operation of the suspension system. A connecting rod 104 passes through the through hole. A first limiting part 1041 and a second limiting part 1042 are provided on the connecting rod 104. The first limiting part 1041 and the second limiting part 1042 are located at the two ends of the through hole, respectively, thereby limiting and protecting the relative travel of the connecting rod 104 in the axial direction and avoiding collisions or disengagement caused by overshoot during suspension adjustment.

[0027] The bottom end of the connecting rod 104 is connected to the satellite 20 to be verified, so that the satellite 20, the connecting rod 104, and the permanent magnet 105 together form an integrated levitation subsystem. During the test, the satellite 20 can achieve attitude motion and response measurement around the target axis with minimal mechanical constraints. The permanent magnet 105 is fixed to the top of the connecting rod 104, and its magnetic axis is set in accordance with the axis of the connecting rod 104, so that the permanent magnet 105 and the first electromagnet 102 are aligned along the same magnetic axis. When the first electromagnet 102 is energized, a controllable magnetic attraction force can be formed between the two. This attraction force is used to counteract the gravity of the subsystem and establish a non-contact levitation state, thereby avoiding interference factors such as friction, gaps, and lubrication failure caused by traditional mechanical support, and more closely resembling the near-frictionless dynamic environment in orbit.

[0028] A laser displacement sensor 106 is fixedly installed on the frame body 101. The laser displacement sensor 106 is mechanically isolated from the motion subsystem. Its measuring component is aligned with the second limiting part 1042 on the connecting rod 104 to acquire the distance information between the laser displacement sensor 106 and the second limiting part 1042 in real time. Based on the initial distance and the current distance information, the distance by which the connecting rod has been raised is determined, and it is judged whether the integrated levitation motion subsystem is in a fully levitated state. If it is not in a fully levitated state, the magnitude of the magnetic attraction force is changed by adjusting the current of the first electromagnet 102 to control the vertical height of the levitation motion subsystem.

[0029] In summary, compared to ground-based satellite attitude verification schemes that rely on air buoyancy or complex multi-degree-of-freedom magnetic levitation structures in related technologies, the magnetic levitation test system for satellite attitude verification proposed in this invention offers significant improvements in structural simplification, environmental adaptability, friction suppression capability, and test repeatability. First, the invention utilizes a first electromagnet and a permanent magnet to form an axial magnetic attraction levitation structure along the same magnetic axis, directly counteracting the gravity of the levitation subsystem with electromagnetic force, thus achieving non-contact support for the satellite in the vertical direction. Compared to magnetic levitation platform schemes in related technologies that still involve mechanical bearings, ball bearings, or auxiliary supports, this structure does not rely on any mechanical contact components during levitation operation, fundamentally eliminating problems such as mechanical friction, gap impact, and lubrication failure under vacuum conditions. This makes the attitude motion process closer to the near-frictionless dynamic environment of satellite operation in orbit, significantly improving the consistency between ground verification results and actual in-orbit conditions. Second, this invention adopts a magnetic levitation technical approach, focusing the verification objective on the most critical and fundamental dynamics and control issues in micro / nano satellite attitude control. Compared to the extremely high requirements for machining accuracy, assembly concentricity, number of sensors, and complexity of control algorithms in five- or three-degree-of-freedom magnetic levitation platforms in related technologies, this embodiment significantly reduces the system's dependence on spatial installation accuracy and multi-sensor collaborative calculation through a single magnetic axis alignment structure and through-hole guiding design. This makes the system structure more compact, the control logic clearer, and the implementation difficulty of the processor and control algorithm significantly reduced, thereby improving the system's engineering feasibility and reliability. In this invention, the through-hole of the connecting body is coaxially set with the magnetic axis, and in conjunction with the axial limiting structure of the connecting rod, it effectively constrains and protects the axial travel of the moving subsystem while ensuring its levitation degree of freedom. This combination of magnetic levitation and passive limiting design makes the system safer during startup, debugging, and abnormal operating conditions, avoiding the structural collision risk caused by control instability or overshoot during the adjustment process of traditional magnetic levitation systems, and facilitating the conduct of multiple rounds of long-term repetitive tests. This invention uses a laser displacement sensor to perform non-contact real-time measurement of the levitation height, and uses this displacement information as feedback for adjusting the magnetic attraction force, realizing closed-loop control of the levitation height. This magnetic adjustment method based on position feedback allows for quantitative determination and fine adjustment of the levitation state, laying the foundation for introducing the satellite's own attitude actuators into experiments and conducting real closed-loop attitude control verification. It overcomes the problem in some prior art solutions where the test object can only passively receive external torque and cannot reflect the actual control process. Because this invention has a simple overall structure and few parts, the requirements for processing precision and assembly conditions are relatively moderate, and it does not rely on high-pressure gas sources or ultra-low temperature superconducting environments, making it easy to implement and maintain under vacuum conditions. The testing cost is significantly lower than that of air-bearing platforms and superconducting magnetic levitation solutions.Meanwhile, the structure is highly adaptable to changes in the size and mass of the satellite under test. It can achieve levitation configuration under different load conditions simply by adjusting the electromagnet current parameters. Therefore, it has strong versatility and repeatability, making it particularly suitable for the engineering ground verification of micro-nano satellite attitude control algorithms and systems.

[0030] In one feasible implementation, the aforementioned satellite attitude verification magnetic levitation test system further includes: A horizontal magnetic field compensation coil group 107 is connected to the frame body 101. The horizontal magnetic field compensation coil group 107 includes at least two sets of horizontal magnetic field compensation coils. The center line of the horizontal magnetic field compensation coils is located between the top of the first electromagnet 102 and the top of the permanent magnet 105.

[0031] For example, this embodiment, based on the aforementioned axial magnetic attraction levitation formed by the first electromagnet 102 and the permanent magnet 105, further introduces a horizontal magnetic field compensation coil group 107 to compensate and shape the transverse magnetic field component in the levitation gap region, thereby improving levitation stability and attitude verification accuracy. Specifically, the horizontal magnetic field compensation coil group 107 is fixedly connected to the frame body 101, so that its spatial position remains unchanged during the test and it is mechanically isolated from the moving subsystem, avoiding direct coupling of structural vibration or assembly deviation of the compensation mechanism to the satellite under test 20.

[0032] The aforementioned horizontal magnetic field compensation coil group 107 includes at least two sets of horizontal magnetic field compensation coils. The centerline of each compensation coil is arranged in the region between the top of the first electromagnet 102 and the permanent magnet 105, that is, in the critical area of ​​the levitation magnetic circuit. The purpose of setting the centerline of the compensation coil in this region is that this region is where the superposition of the magnetic fields of the first electromagnet 102 and the permanent magnet 105 is strongest and the gradient change is most significant. At the same time, it is also the spatial segment where the levitation height and lateral stability of the moving subsystem are most sensitive. By applying a controllable horizontal magnetic field at this location, lateral interference introduced by lateral magnetic field asymmetry, eccentric assembly, external geomagnetism, or surrounding ferromagnetic materials can be canceled without changing the direction of the main levitation force, thereby reducing the risk of the moving subsystem generating lateral bias force and overturning moment.

[0033] In practical operation, when the first electromagnet 102 is energized to generate an axial magnetic attraction to counteract the gravity of the moving subsystem, the system may still generate a non-negligible horizontal magnetic field component within the suspension gap due to factors such as slight misalignment of the magnetic axes, uneven remanence of the permanent magnet, magnetic permeability disturbance of the frame structure, or environmental geomagnetism. This horizontal magnetic field component will generate a lateral force or lateral torque on the permanent magnet 105, causing the connecting rod 104 to exhibit a slight lateral sway or eccentric tendency, which in turn manifests as suspension height jitter, increased attitude coupling disturbance, and even nonlinear interference such as rubbing against the limiting part and rebounding, ultimately reducing the reliability of attitude control verification. By setting at least two sets of horizontal magnetic field compensation coils, adjustable compensation magnetic fields can be generated along mutually orthogonal or oppositely arranged horizontal directions, enabling the system to achieve component-level cancellation of lateral disturbances in different directions. Furthermore, the compensation current can be adjusted according to the real-time measured displacement, tilt angle, or vibration characteristics, thereby forming a dynamic suppression capability against the lateral magnetic field.

[0034] Furthermore, the at least two sets of structures in the horizontal magnetic field compensation coil group 107 allow the compensation to go beyond simple lateral force cancellation, and can also be used to shape the magnetic field distribution within the suspension gap. By differentially energizing to form a symmetrical lateral magnetic field gradient locally, a restoring force effect pointing towards the center can be provided when the moving subsystem exhibits slight eccentricity, thereby effectively increasing lateral stiffness and reducing the sway amplitude of the connecting rod 104 within the through hole. By unidirectionally energizing, the geomagnetic background field in a specific direction can be completely canceled, making the magnetic field in the direction of the main magnetic axis purer and reducing additional disturbances introduced by the external field during attitude verification.

[0035] Therefore, this embodiment can improve the anti-interference capability and stability of the magnetic levitation system in real test environment without significantly increasing the complexity of the mechanical structure, making the levitation subsystem closer to the on-orbit dynamic conditions of only controlled torque and weak external disturbance, thereby improving the accuracy, repeatability and engineering applicability of micro-nano satellite attitude control verification.

[0036] In one feasible implementation, the aforementioned satellite attitude verification magnetic levitation test system further includes: A damping disc 108 is connected to the connecting rod 104 near its bottom end; a second electromagnet 109 and a third electromagnet 110 are connected to the frame body 101, and the second and third electromagnets are symmetrically arranged about the axis of the damping disc.

[0037] For example, in order to further suppress residual swaying and oscillation of the levitation subsystem during start-up leveling, disturbance impact or attitude movement, this embodiment provides a damping disk 108 near the bottom of the connecting rod 104, and provides a second electromagnet 109 and a third electromagnet 110 on the frame body 101. The second electromagnet 109 and the third electromagnet 110 are arranged symmetrically about the axis of the damping disk 108, thereby forming a non-contact electromagnetic damping / stabilization structure, which is used to suppress the lateral swaying, eccentricity and transient vibration of the levitation subsystem and stabilize its attitude without introducing mechanical friction.

[0038] Specifically, the damping disk 108 is fixedly connected to the connecting rod 104 near its bottom end, making it part of the levitated subsystem along with the satellite 20 to be verified. Therefore, the motion of the damping disk 108 accurately reflects the lateral micro-displacement, angular sway, and micro-disturbance response generated by the internal actuators of the subsystem in its levitated state. The damping disk 108 can be made of conductive materials (such as aluminum alloy or copper alloy). Its working mechanism is that when the damping disk 108 moves relative to the surrounding magnetic field, eddy currents are induced inside the disk. These eddy currents interact with the external magnetic field to generate an electromagnetic damping force in the opposite direction to the velocity of motion, thereby attenuating the mechanical vibration energy of the subsystem as heat dissipation, achieving a contactless and wear-free damping effect. Because this damping process does not rely on lubrication or mechanical friction pairs, it is suitable for vacuum environments and avoids the static friction, creeping effect, and wear particle contamination problems introduced by traditional contact damping.

[0039] The second electromagnet 109 and the third electromagnet 110 are fixed to the frame body 101 and are symmetrically arranged about the axis of the damping disk 108, so that they can form a symmetrical magnetic field action area around the damping disk 108. The significance of the symmetrical arrangement is as follows: First, through the symmetrical superposition of the magnetic fields on both sides, the net lateral force on the damping disk 108 when it is in the ideal central position of the system approaches zero, thus not destroying the essential constraint of free motion and avoiding continuous lateral attraction caused by the bias of the magnetic field on one side. Second, when the damping disk 108 experiences lateral displacement or angular sway due to external disturbances or slight assembly eccentricity, the magnetic coupling between the damping disk and the electromagnets on both sides will become asymmetrical, thereby generating a velocity-related damping force opposite to the motion in the displacement direction, which can be superimposed to form a certain recovery trend, allowing the moving subsystem to return to the stable equilibrium region more quickly, significantly reducing the sway and stabilization time of the suspension system.

[0040] In actual testing, after the first electromagnet 102 and the permanent magnet 105 establish axial levitation, the moving subsystem may still experience low-frequency oscillations, lateral swaying, or transient disturbances caused by the start-stop of the satellite's internal flywheel or the operation of the magnetic torque device. Without an effective energy dissipation channel, these oscillations will decay over a long period in a near-frictionless environment, leading to fluctuations in levitation altitude measurement, contamination of the attitude response signal by vibration noise, and even the risk of the connecting rod 104 rubbing against the through-hole area. By setting up a damping disk 108 and utilizing the second electromagnet 109 and the third electromagnet 110 to form a controllable magnetic field, this embodiment can provide adjustable electromagnetic damping without increasing mechanical constraints. For example, during the test startup phase, the excitation current of the second and third electromagnets can be appropriately increased to enhance damping and accelerate system convergence and leveling. During the attitude control performance verification phase, the excitation current can be reduced to decrease additional disturbances, allowing the system to maintain low-damping characteristics closer to those in orbit. When abnormal oscillations or impact trends are detected, the damping can be instantaneously increased to achieve rapid steady-state capture, improving test safety and repeatability.

[0041] Therefore, this embodiment, through a non-contact damping structure of damping disk and symmetrical electromagnet, effectively solves the problem of low-damped oscillations that are difficult to decay quickly in magnetic levitation test systems while maintaining the advantages of vacuum applicability and low friction. It reduces the contamination of attitude verification data by lateral sway, improves suspension stability, test efficiency and result consistency, and makes the system more suitable for high-fidelity ground verification of micro-nano satellite attitude control algorithms and actuators.

[0042] In one feasible implementation, the aforementioned satellite attitude verification magnetic levitation test system further includes: A high-speed camera, which is fixed on the frame body 101.

[0043] For example, this embodiment further introduces a high-speed camera based on the above-mentioned magnetic levitation test system, and fixes the high-speed camera on the frame body 101 so that it maintains a stable spatial position with the ground reference throughout the test process, thereby constructing a non-contact visual observation and verification method for satellite attitude motion and suspension state, in order to improve the observability, data integrity and result credibility of the attitude verification process.

[0044] Specifically, the installation position and line-of-sight direction of the high-speed camera can be set according to experimental requirements, aligning it with the connecting rod 104, the damping disk 108, or the feature-marked area on the satellite 20 to be verified. Since the high-speed camera is rigidly connected to the frame body 101, its imaging coordinate system can be used as a fixed reference coordinate system. This allows for the stable mapping of the captured high-speed sequence images to a ground reference system during subsequent data processing, enabling accurate inversion of the motion state of the suspended subsystem. Compared to relying solely on the laser displacement sensor 106 to obtain single-axis displacement information, the high-speed camera can provide two-dimensional or even three-dimensional temporal visual information for observing the minute sway of the connecting rod 104 in the through-hole, the lateral vibration trajectory of the damping disk 108, and the coupled swaying behavior that may accompany the attitude motion of the satellite 20 to be verified.

[0045] In practical operation, when the levitation subsystem is in a fully levitated state and performs attitude control experiments, the high-speed camera continuously acquires images at a high frame rate. This allows for clear capture of transient dynamic processes induced by internal satellite actuators (such as reaction flywheel acceleration / deceleration, magnetic torque device operation, or structural flexible vibration). These processes are often characterized by small amplitude, high frequency, and short duration, making them difficult to accurately acquire using low-sampling-rate sensors. However, the high-speed camera can record these processes with millisecond or even microsecond-level time resolution, providing intuitive evidence for analyzing the transient response of attitude control, coupled vibration propagation paths, and damping effects.

[0046] Furthermore, the visual data acquired by the high-speed camera can be synchronized in time with the driving current signals of the laser displacement sensor 106 and the first electromagnet 102, as well as the control signals of the horizontal magnetic field compensation coil group and the damping electromagnet, thereby achieving multi-source data fusion analysis. By comparing the correspondence between the displacement, angle, and vibration mode obtained from visual measurements and the magnetic levitation control quantities, it can be used to verify the accuracy of the magnetic levitation system modeling, evaluate the adjustment effect of compensation and damping parameters, and help discover nonlinear disturbances or assembly deviations that are difficult to detect with a single sensor.

[0047] Furthermore, in terms of system debugging and safety assurance, high-speed cameras can also serve as a direct means of monitoring and recording. When improper settings of levitation height adjustment, magnetic field compensation, or damping parameters lead to abnormal swaying, eccentric approach to the limit, or potential collision risks in the moving subsystem, the high-speed camera can record and replay the abnormal process in a timely manner, providing a basis for post-event analysis and parameter optimization, and reducing the experimental risks during repeated system debugging. Therefore, by introducing a high-speed camera, this embodiment significantly enhances the satellite attitude verification magnetic levitation test system's ability to perceive and analyze levitation state and attitude motion without interfering with the levitation dynamics environment. This makes ground tests more visual, quantifiable, and traceable, thereby further improving the accuracy and engineering practicality of ground verification of micro-nano satellite attitude control.

[0048] In one feasible implementation, the measuring component of the laser displacement sensor 106 is correspondingly provided with the second limiting part 1042, which is frustum-shaped.

[0049] For example, the laser displacement sensor 106 is fixedly mounted on the frame body 101, and its measuring beam is aligned with the surface area of ​​the second limiting part 1042 along a predetermined direction to obtain the distance information between the laser displacement sensor 106 and the second limiting part 1042. Since the second limiting part 1042 is rigidly connected to the connecting rod 104, its axial position change can directly reflect the displacement change of the levitation subsystem in the vertical direction. Therefore, using the second limiting part 1042 as the target surface for laser displacement measurement can avoid directly measuring the satellite body with a complex shape, thereby reducing the measurement uncertainty caused by irregular satellite structure, inconsistent surface reflection characteristics, or changes in installation attitude.

[0050] Designing the second limiting part 1042 as a frustum-shaped structure has several technical advantages. First, the frustum-shaped structure has a continuously varying outer diameter along the axial direction, and its outer surface is distributed in a regular conical pattern relative to the axis of the connecting rod. This allows the laser displacement sensor 106 to stably receive the reflected signal even with slight lateral offsets or angular deviations, thereby reducing the risk of measurement loss or jumps caused by slight swaying, eccentricity, or installation errors in the levitation subsystem. Compared to planar or sharp-edged structures, the frustum-shaped surface is less prone to localized high reflections or multipath reflections, which is beneficial for the stable reception and calculation of laser ranging signals.

[0051] During suspension adjustment and attitude movement, the connecting rod 104 may experience slight lateral swaying or tilting due to external disturbances or the action of the internal actuator. In this case, the effective measurement point between the frustum-shaped second limiting part 1042 and the laser displacement sensor 106 will smoothly migrate on the conical surface, without the problem of the measurement target suddenly detaching from the measurement spot or abrupt change in the reflection angle. This ensures that the displacement signal changes continuously over time, avoids interruption of the measurement signal or non-physical abrupt changes, and is beneficial to the stable operation of the suspension height closed-loop control algorithm.

[0052] The frustum-shaped second limiting part 1042 also serves a dual function as a structural limiting part and a measurement reference. When the connecting rod 104 experiences excessive axial displacement under abnormal operating conditions, the frustum-shaped limiting part can form a restricted contact with the connecting body 103 with a larger contact area, reducing the concentration of impact stress. Under normal operating conditions, its regular geometric shape can serve as a stable and repeatable optical measurement reference, facilitating the maintenance of consistent measurement conditions between different test batches and improving the comparability of test results.

[0053] Therefore, this embodiment, by specifically designing the laser displacement sensor 106 and the frustum-shaped second limiting part 1042, effectively improves the robustness and continuity of suspension height measurement under micro-oscillation and micro-eccentric conditions without adding additional sensors or complex mechanisms. This provides a more stable and reliable measurement basis for the fine adjustment of magnetic levitation suspension height and ground verification of micro-nano satellite attitude control.

[0054] Secondly, such as Figure 3 As shown, the present invention proposes a control method for the magnetic levitation test system for satellite attitude verification as described in the first aspect, comprising: S210. After the satellite to be verified has completed the test preparation work, control the first electromagnet to be energized and obtain the distance information between the laser displacement sensor and the second limiting part. S210. Based on the aforementioned distance information, control the current information of the first electromagnet to control the attraction between the first electromagnet and the permanent magnet, so that the distance information between the first electromagnet and the permanent magnet is within a preset distance range.

[0055] For example, after the satellite to be verified 20 has completed installation, trimming and safety checks, a closed loop is formed by the distance feedback of the laser displacement sensor and the current adjustment of the first electromagnet, so that the axial gap between the first electromagnet 102 and the permanent magnet 105 is stabilized within a preset range, thereby realizing electromagnetic compensation for the gravity of the levitation subsystem on the ground and establishing an attitude verification environment with approximately no mechanical contact, low friction and low constraint.

[0056] Specifically, in step S210, the control system first energizes the first electromagnet 102. The first electromagnet 102, consisting of an iron core and a wound coil, is fixed to the top of the frame body 101. Its main function is to act as a controllable magnetic field source: by adjusting the magnitude of the energizing current, the magnetic field strength is changed, thereby changing the magnetic attraction force on the permanent magnet 105 below. It is a key actuator for achieving stable levitation and height adjustment. At the same time, the laser displacement sensor 106 is aligned with the second limiting part 1042 and measures the distance information between them in real time. Since the second limiting part 1042 is rigidly connected to the connecting rod 104, and the bottom end of the connecting rod is connected to the satellite 20 to be verified, this distance information can equivalently characterize the displacement state of the levitation subsystem in the vertical direction, and can be used to determine whether the gravity has been fully unloaded and the system has entered the stable levitation range.

[0057] In step S220, the control system performs closed-loop adjustment of the energizing current of the first electromagnet 102 based on distance information: it compares the currently measured distance with a preset distance range; if the distance is too large (indicating insufficient attraction and a significant downward trend of the mover), the electromagnet current is increased to strengthen the magnetic field; if the distance is too small (indicating excessive attraction and a significant upward trend of the mover), the electromagnet current is decreased to weaken the magnetic field. Through this closed-loop mechanism of distance measurement, comparison, and current adjustment, the distance between the first electromagnet 102 and the permanent magnet 105 is stably maintained within the preset range, thereby continuously offsetting the gravitational component of the levitated mover system by the magnetic pole attraction formed between them. This achieves load-bearing and attitude movement conditions without mechanical support, avoiding the friction, gap impact, and vacuum lubrication failure problems caused by traditional bearings, balls, or contact supports, and is closer to the near-frictionless dynamic environment of space.

[0058] A permanent magnet 105 is placed directly below and aligned with the center of the first electromagnet 102, maintaining a small air gap (i.e., pole spacing) between them. In this structure, the magnetic attraction force can act directionally on the moving part system to overcome gravity and establish levitation. The magnitude of the attraction force can be estimated using a magnetic circuit approximation model; an exemplary magnetic force calculation formula can be expressed as:

[0059] in, Remanence is an intrinsic property of the material; The relative permeability of the material; l is the air gap length; l is the magnet length; Let be the vacuum permeability and A be the magnet area. It is evident that the air gap g and the magnetic field parameters jointly determine the attractive force level. When the control system alters the magnetic field conditions by adjusting the current of the first electromagnet, it effectively changes the attractive force generated by the coupling between the electromagnet and the permanent magnet, thereby achieving stable control of the levitation height (i.e., the first distance). By stabilizing this distance within a preset range, this method not only quickly determines and maintains the fully levitated / effectively unloaded working state but also provides a stable and repeatable physical experimental basis for subsequent satellite attitude motion response measurement and attitude control closed-loop verification.

[0060] In one feasible implementation, the control of the energizing current information of the first electromagnet based on the distance information includes: The distance information obtained above is compared with the preset distance information corresponding to the preset target suspension distance to obtain the distance deviation; A suspension state error signal is constructed based on the aforementioned distance deviation, and a corresponding current adjustment amount is generated based on the aforementioned error signal. The current adjustment amount is superimposed on the initial energizing current of the first electromagnet to serve as the energizing current information of the first electromagnet, so as to dynamically adjust the magnetic field strength generated by the first electromagnet.

[0061] In one feasible implementation, when the second limiting part is frustum-shaped, the current adjustment amount is calculated based on the following formula:

[0062]

[0063] Where k is the current sampling time; This is the total output of the controller, i.e., the PWM value applied to the electromagnet; It is the basic feedforward control quantity used to balance the gravity of the levitation vehicle; This represents the current position error, which is the difference between the measured value and the set value. This represents the measured value from the laser displacement sensor at the current moment. This is the measured value of the laser displacement sensor at the previous moment; This is the velocity value at the current moment after undergoing a first-order low-pass filter. This is the velocity value after first-order low-pass filtering at the previous moment; These are the velocity filter coefficients; These are the proportional, integral, and differential gain coefficients, respectively.

[0064] For example, Figure 4 This is a schematic diagram illustrating the ranging principle of a laser displacement sensor provided in an embodiment of this application. Figure 5 This is a schematic diagram illustrating the ranging process of a laser displacement sensor according to an embodiment of this application. The control system adjusts the voltage through PWM (Pulse Width Modulation), thereby changing the current of the electromagnet and achieving magnetic levitation control. Specifically, the PID controller adjusts the duty cycle of the PWM signal, i.e., controls the periodic change of the voltage, to precisely regulate the current and thus achieve stable control of the levitation position.

[0065] Assuming the target levitation point is set to 30, but the actual magnet placement is at 30.5, there is an error between the magnet and the target levitation point. To adjust the magnet to the correct position, the system first uses a basic feedforward control variable... Initial adjustments are made to move the magnet to the target point. This process primarily aims to quickly compensate for large-scale displacement errors. Then, the PID controller calculates the position error based on real-time feedback. The PID controller consists of three parts: a proportional term... Adjust the current based on the error at the current position to quickly reduce the error; integral term Correcting small errors accumulated over time to ensure long-term system stability; differential term Adjustments are made based on the rate of error change, thereby predicting and reducing future errors in advance.

[0066] The control signal calculated by PID controller adjusts the duty cycle of the PWM (Pulse Width Modulation) to control the voltage signal level, which in turn affects the current to the electromagnet. When the current changes, the magnetic field strength of the electromagnet changes accordingly, thus altering the buoyancy of the magnet in the levitation system and maintaining system stability. The control system continuously adjusts the PWM duty cycle based on feedback, ensuring the magnet maintains a stable levitation state near the target position, eliminating errors in real time and responding to external disturbances. In this way, the magnetic levitation system can achieve precise attitude control while maintaining stable buoyancy.

[0067] In one feasible implementation, where the aforementioned magnetic levitation test system for satellite attitude verification further includes a horizontal magnetic field compensation coil group, the control method further includes: After the first electromagnet and the permanent magnet form a magnetic levitation state, the horizontal magnetic field compensation coil group is energized to generate a compensation magnetic field in the horizontal direction. The attitude oscillation characteristic information of the satellite to be verified in a suspended state is obtained, wherein the attitude oscillation characteristic information includes oscillation period information; Based on the above attitude oscillation characteristic information, the current ratio and current amplitude of each compensation coil in the above horizontal magnetic field compensation coil group are adjusted to change the direction and intensity of the above compensation magnetic field. By iteratively adjusting the direction and intensity of the aforementioned compensating magnetic field, the attitude oscillation characteristics of the satellite to be verified are made to meet the preset stability conditions, thereby reducing the impact of the magnetic field inhomogeneity in the horizontal direction of the magnetic levitation system on attitude verification.

[0068] For example, such as Figure 6 As shown, Figure 6 This is a schematic diagram of the working principle of a horizontal magnetic field compensation coil group proposed in this embodiment. In order to reduce the impact of magnetic disturbance caused by the non-uniformity of the magnetic field between the first electromagnet and the permanent magnet in the horizontal direction (X and Y directions) on the attitude verification results, a horizontal magnetic field compensation coil group is further set in the magnetic levitation test system. The horizontal magnetic field compensation coil group preferably consists of two pairs of compensation coils arranged orthogonally, that is, one pair generates a horizontal compensation magnetic field along the X direction and the other pair generates a horizontal compensation magnetic field along the Y direction. The center positions of the two pairs of coils are aligned with the levitation gap area, so that they form a controllable synthetic horizontal magnetic field in the levitation working area.

[0069] After the first electromagnet and permanent magnet form a stable magnetic levitation state, the horizontal magnetic field compensation coil group is energized to generate a compensation magnetic field in the horizontal direction. This compensates for or weakens the horizontal magnetic field inhomogeneity caused by structural bias, magnetic circuit asymmetry, assembly errors, or external environmental magnetic disturbances. When horizontal magnetic field inhomogeneity exists, the levitation system is subjected to additional horizontal magnetic force or magnetic torque, thereby inducing attitude oscillations or wobbling of the satellite under test in the levitation state. To quantify the impact of this horizontal magnetic field inhomogeneity and form a closed-loop adjustable evaluation index, this embodiment obtains the attitude oscillation characteristic information of the satellite under test in the levitation state. The attitude oscillation characteristic information includes at least the oscillation period information T. According to the description in the figure, the oscillation period of the levitation system has a corresponding relationship with its moment of inertia I and restoring torque coefficient k, which can be expressed by an exemplary formula as follows: , where I is the moment of inertia of the suspension system and k is the restoring torque coefficient.

[0070] When the magnetic disturbance caused by the non-uniformity of the horizontal magnetic field decreases, the equivalent disturbance torque on the system weakens, which manifests as the attitude oscillation tending to converge, the oscillation period changing and gradually approaching a more stable state. Therefore, the magnitude of the horizontal magnetic torque can be indirectly reflected by monitoring the length of the oscillation period, and the compensation effect can be evaluated accordingly.

[0071] Based on the aforementioned attitude oscillation characteristics, this embodiment further adjusts the current ratio and amplitude of each compensation coil in the horizontal magnetic field compensation coil group to change the direction and intensity of the compensation magnetic field. Specifically, the direction of the synthesized compensation magnetic field is first changed by controlling the current ratio of the X-axis coil and the Y-axis coil, allowing the direction of the compensation magnetic field to be continuously adjusted within the range of 0° to 360°, so as to gradually align with the "horizontal magnetic field non-uniformity direction" that causes the strongest oscillation. During this process, the total current amplitude of the coil group can be kept approximately constant, so that the intensity of the compensation magnetic field remains basically unchanged, only the direction is changed. The oscillation period is continuously acquired by a high-speed camera or attitude measurement module, and its changing trend is compared. The compensation direction corresponding to a longer oscillation period or a smaller oscillation amplitude is determined as the optimal direction, that is, it is considered that this direction can maximally offset the non-uniform magnetic field in the horizontal direction. After determining the compensation direction, the current ratio of the X-axis and Y-axis coils is kept constant, and the intensity of the compensation magnetic field is adjusted by synchronously amplifying or reducing the coil current amplitude, and the oscillation period and other characteristics are continuously monitored until the oscillation period, oscillation amplitude, or convergence time meets the preset stability conditions, thereby determining the optimal compensation intensity.

[0072] Finally, through the iterative adjustment process of direction scanning, direction locking, and intensity fine-tuning described above, the attitude oscillation characteristics of the satellite under test in the suspended state meet the preset stability conditions, effectively compensate for the non-uniformity of the horizontal magnetic field, reduce the attitude error and test uncertainty introduced by the horizontal magnetic disturbance, and thus improve the stability of the magnetic levitation attitude verification and the reliability of the verification results.

[0073] In one feasible implementation, where the above-described magnetic levitation test system for satellite attitude verification further includes a damping disk, a second electromagnet, and a third electromagnet, the method further includes: After completing an attitude verification test, the rotational state information of the satellite to be verified in magnetic levitation state was obtained; When it is determined that the rotation state of the satellite to be verified does not meet the preset reset conditions, the second electromagnet and the third electromagnet are energized to generate a magnetic field at the damping disk. The electromagnetic damping effect generated by the movement of the damping disk in the magnetic field is used to attenuate the rotational state of the connecting rod and the satellite to be verified. The calculation formula for the electromagnetic damping effect is as follows:

[0074] Where F represents magnetic force. Remanence is an intrinsic property of the material; The relative permeability of the material; l is the air gap length; l is the magnet length; Let A be the vacuum permeability, and A be the area of ​​the magnet. When it is determined that the rotation state of the satellite to be verified meets the preset reset conditions, the second electromagnet and the third electromagnet are de-energized to release the electromagnetic damping effect on the damping disk, thereby enabling the magnetic levitation test system to enter the next attitude verification test state.

[0075] For example, in order to enable the magnetic levitation attitude verification to be carried out continuously in the manner of test-reset-retest, and to avoid the satellite to be verified from still having residual rotation or sway after one test, which would affect the initial conditions of the next test, the magnetic levitation test system is further equipped with a damping disk, a second electromagnet and a third electromagnet, which are used to quickly attenuate and reset the rotation state without contact or introducing mechanical friction.

[0076] Specifically, after completing an attitude verification test, the control system first acquires the rotational state information of the satellite under test in magnetic levitation. This rotational state information may include, but is not limited to, rotation angle, angular velocity, rotation direction, oscillation amplitude, or attitude change rate, used to characterize whether the connecting rod and the satellite under test are still in a state of significant rotation or oscillation. Subsequently, the control system compares this rotational state information with preset reset conditions. These preset reset conditions limit the allowable residual angular velocity threshold, residual oscillation amplitude threshold, or attitude stabilization time threshold before entering the next test. When it is determined that the rotational state of the satellite under test does not meet the preset reset conditions, the control system energizes the second and third electromagnets, causing them to establish a preset spatially distributed magnetic field in the area where the damping disk is located. Preferably, this magnetic flux component can generate a relative cut with the direction of motion of the damping disk. At this time, the damping disk moves in this magnetic field along with the residual rotation of the connecting rod and the satellite under test. Induced eddy currents are generated inside the conductor of the damping disk, and these eddy currents further generate electromagnetic torques opposite to the original motion trend, thereby producing an electromagnetic damping effect. This electromagnetic damping effect is equivalent to applying non-contact braking related to angular velocity to the system. It can continuously consume rotational kinetic energy and convert it into Joule heat of the damping disc, so that the angular velocity of the connecting rod and the satellite to be verified gradually decreases and the swing amplitude gradually converges, thereby achieving attenuation and reset of the rotational state.

[0077] During control, the system can periodically or in real-time update rotational state information and adjust the energizing duration or magnetic field strength of the second and third electromagnets according to the attenuation effect to ensure reset efficiency while avoiding excessive damping that could introduce new attitude disturbances. When the rotational state of the satellite to be verified meets the preset reset conditions, i.e., the residual angular velocity, residual oscillation amplitude, or attitude change rate drops to within the threshold range and remains stable, the second and third electromagnets are de-energized to release the electromagnetic damping effect on the damping disk, allowing the system to return to a low-disturbance free-floating state. This enables the magnetic levitation test system to have repeatable and rapidly switchable initial conditions for the next attitude verification test, improving the continuity of the attitude verification process and the consistency of test data.

[0078] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A magnetic levitation test system for satellite attitude verification, characterized in that, include: Framework body, The first electromagnet is fixedly connected to the top of the frame body; A connector is fixedly connected to the first electromagnet. The bottom end of the connector is provided with a through hole, and the axis of the through hole is correspondingly arranged with the magnetic axis of the first electromagnet. A connecting rod, the connecting rod including a first limiting part and a second limiting part, the connecting rod passing through the through hole of the connecting body, the first limiting part and the second limiting part being located at both ends of the through hole respectively, and the bottom end of the connecting rod being connected to the satellite to be verified; A permanent magnet is fixedly connected to the top end of the connecting rod, and the magnetic axis of the permanent magnet is arranged corresponding to the axis of the connecting rod. A laser displacement sensor is fixedly connected to the frame body and is used to measure the distance information between the laser displacement sensor and the second limiting part.

2. The magnetic levitation test system for satellite attitude verification according to claim 1, characterized in that, The satellite attitude verification magnetic levitation test system also includes: A horizontal magnetic field compensation coil group is connected to the frame body. The horizontal magnetic field compensation coil group includes at least two sets of horizontal magnetic field compensation coils. The center line of the horizontal magnetic field compensation coil is located between the top ends of the first electromagnet and the permanent magnet.

3. The magnetic levitation test system for satellite attitude verification according to claim 1, characterized in that, The satellite attitude verification magnetic levitation test system also includes: A damping disc, which is connected to the connecting rod near its bottom end; A second electromagnet and a third electromagnet are connected to the frame body and are symmetrically arranged about the axis of the damping disc.

4. The magnetic levitation test system for satellite attitude verification according to claim 1, characterized in that, The satellite attitude verification magnetic levitation test system also includes: A high-speed camera, which is fixed to the frame body.

5. The magnetic levitation test system for satellite attitude verification according to claim 1, characterized in that, The measuring component of the laser displacement sensor is correspondingly arranged with the second limiting part, which is frustum-shaped.

6. A control method for the magnetic levitation test system for satellite attitude verification as described in any one of claims 1 to 5, characterized in that, include: After the satellite to be verified completes the test preparation work, the first electromagnet is energized, and the distance information between the laser displacement sensor and the second limiting part is obtained. Based on the distance information, the current information of the first electromagnet is controlled to control the attractive force between the first electromagnet and the permanent magnet, so that the distance information between the first electromagnet and the permanent magnet is within a preset distance range.

7. The control method according to claim 6, characterized in that, The method of controlling the energizing current information of the first electromagnet based on the distance information includes: The distance information is obtained and compared with the preset distance information corresponding to the preset target suspension distance to obtain the distance deviation. A suspension state error signal is constructed based on the distance deviation, and a corresponding current adjustment amount is generated according to the error signal; The current adjustment amount is superimposed on the initial energizing current of the first electromagnet to serve as the energizing current information of the first electromagnet, so as to dynamically adjust the magnetic field strength generated by the first electromagnet.

8. The control method according to claim 7, characterized in that, When the second limiting part is frustum-shaped, the current adjustment amount is calculated based on the following formula: Where k is the current sampling time; This is the total output of the controller, i.e., the PWM value applied to the electromagnet; It is the basic feedforward control quantity used to balance the gravity of the levitation vehicle; This represents the current position error, which is the difference between the measured value and the set value. This represents the measured value from the laser displacement sensor at the current moment. This is the measured value of the laser displacement sensor at the previous moment; This is the velocity value at the current moment after undergoing a first-order low-pass filter. This is the velocity value after first-order low-pass filtering at the previous moment; These are the velocity filter coefficients; These are the proportional, integral, and differential gain coefficients, respectively.

9. The control method according to claim 7, characterized in that, In the case that the magnetic levitation test system for satellite attitude verification also includes a horizontal magnetic field compensation coil group, the control method further includes: After the first electromagnet and the permanent magnet form a magnetic levitation state, the horizontal magnetic field compensation coil group is energized to generate a compensation magnetic field in the horizontal direction, wherein the strength of the compensation magnetic field generated in the horizontal direction is determined by the following formula: The central magnetic flux density generated by the coil; The vacuum permeability; The number of turns in a single coil; The magnitude of the current; The radius of the coil; The distance between the two coils; The attitude oscillation characteristic information of the satellite to be verified in a suspended state is obtained, wherein the attitude oscillation characteristic information includes oscillation period information; Based on the attitude oscillation characteristic information, the current ratio and current amplitude of each compensation coil in the horizontal magnetic field compensation coil group are adjusted to change the direction and intensity of the compensation magnetic field. By iteratively adjusting the direction and intensity of the compensating magnetic field, the attitude oscillation characteristics of the satellite to be verified are made to meet the preset stability conditions, so as to reduce the impact of the magnetic field inhomogeneity in the horizontal direction of the magnetic levitation system on attitude verification.

10. The control method according to claim 7, characterized in that, In the case where the magnetic levitation test system for satellite attitude verification further includes a damping disk, a second electromagnet, and a third electromagnet, the method further includes: After completing an attitude verification test, the rotational state information of the satellite to be verified in magnetic levitation state is obtained; When it is determined that the rotation state of the satellite to be verified does not meet the preset reset condition, the second electromagnet and the third electromagnet are energized to generate a magnetic field at the damping disk. The electromagnetic damping effect generated by the movement of the damping disk in the magnetic field is used to attenuate the rotational state of the connecting rod and the satellite to be verified. The calculation formula for the electromagnetic damping effect is as follows: Where F represents magnetic force. Remanence is an intrinsic property of the material; The relative permeability of the material; l is the air gap length; l is the magnet length; Let A be the vacuum permeability, and A be the area of ​​the magnet. When it is determined that the rotation state of the satellite to be verified meets the preset reset condition, the second electromagnet and the third electromagnet are de-energized to release the electromagnetic damping effect on the damping disk, thereby enabling the magnetic levitation test system to enter the next attitude verification test state.

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