Two-dimensional translation actuator for attitude control of drag sail vehicles

Abstract

The application discloses a drag sail aircraft attitude control actuator, which comprises a platform frame, a moving plate, a stepping motor and the like, the stepping motor fixed in the frame drives the moving plate to realize linear motion in X and Y directions; the moving plate is designed with array mounting holes, which are used for mounting the moving plate on the leeward surface of a satellite, so that the space in the satellite is not occupied, and the satellite center of mass can be preliminarily adjusted. The control mechanism of the application is that after the deorbiting device is completely unfolded, the relative position between the deorbiting device and the satellite body is adjusted by adjusting the moving plate in X and Y directions, so that the position of the satellite center of mass and the aerodynamic pressure center is changed, and thus the expected aerodynamic moment can be generated to control the satellite attitude. The application introduces the mass moment technology to break the limitation that the traditional sail spacecraft is difficult to adjust the attitude, so that the satellite equipped with the drag sail can perform attitude control in the deorbiting disposal process, and thus the deorbiting collision probability is reduced.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft deorbiting, and specifically relates to an attitude control actuator for a drag sail aircraft. Background Technology

[0002] With the continuous development of aerospace technology, large-scale low-Earth orbit (LEO) constellation launch plans are emerging one after another. Since the launch of the first artificial satellite, humans have launched more than 4,000 satellites into space. Excluding approximately 800 still operational and a few deorbited LEO satellites, most have become space debris. Currently, some large-scale constellation plans are underway, including SpaceX's Starlink project, which consists of 42,000 satellites. By February 2023, Starlink had reached a total of 4,200 satellites. China's satellite internet project also officially launched in April 2021. Considering other international constellation plans of various sizes, the number of small satellites in orbit will increase to more than 50,000 in the coming years.

[0003] Due to the sheer number of satellites, the constellation itself has a high probability of being struck by space debris. Secondly, small satellites that experience sudden malfunctions or reach the end of their lifespan will remain in space for extended periods, becoming space debris. This continuously increases the probability of collisions with other satellites in orbit, potentially leading to chain reactions and severely impacting high-value spacecraft and normal space activities. Efficient and reliable deorbiting of satellites during sudden malfunctions or at the end of their lifespan is a crucial solution to this problem. Currently, most satellites lack effective deorbiting systems, resulting in a growing amount of space debris in Earth orbit, posing a potential danger to spacecraft already in orbit. Current technology is insufficient for the large-scale and effective deorbiting of spacecraft that have already failed and become space debris. Therefore, equipping future satellites with deorbiting systems is a primary measure to mitigate the increase in space debris.

[0004] The drag sail deorbiting method has advantages such as high reliability, low cost and good applicability. It has been demonstrated and verified in orbit on multiple micro and nano satellite models at home and abroad, and has broad prospects for large-scale application in the future.

[0005] NASA's Nanosail-D (22) deorbiting device with a braking sail. nd The Annual AIAA / USU Braking Sail is the only publicly reported braking sail device that has achieved on-orbit demonstration and verification. The device occupies 2U (20cm×10cm×10cm) of space within the satellite.

[0006] The University of Toronto in Canada has developed a deorbiting device for micro / nano satellites weighing less than 20 kg. Its main structure is manufactured using 3D printing technology and a novel carbon fiber composite material (WindformXT 2.0). This modular assembly design not only allows for flexible installation of the deorbiting device but also reduces the possibility of failure. When used on a CubeSat, the device requires 0.5U (5cm × 10cm × 10cm) of space within the satellite.

[0007] The principle of drag sail deorbiting is to increase aerodynamic drag to reduce orbital altitude. Currently, most drag sail deorbiting designs are passive deorbiting methods, with deorbiting times lasting several years. Spacecraft equipped with deorbit sails typically employ passive attitude stabilization during orbital passivation, resulting in an uncontrolled deorbiting path. Using drag sails to decelerate the deorbiting of hundreds or thousands of microsatellites and nanosatellites would cause the deorbiting process to traverse multiple normally functioning constellation layers without control, significantly increasing the probability of collision. Studies have shown that the collision probability during the uncontrolled deorbiting phase is hundreds of times higher than that during the normal operation phase.

[0008] Mass moment technology is well-suited for attitude control under aerodynamic forces. Its principle is based on using the movement of several movable mass blocks within the aircraft to change the aircraft's center of gravity, thereby adjusting the aerodynamic drag torque to achieve attitude maneuver control. The earliest publicly reported application of mass moment control technology was in the field of reentry vehicles in 1984. Scientists at the U.S. Naval Surface Warfare Research Center, including Regan, designed a single-degree-of-freedom movable mass trim controller to improve the terminal guidance accuracy of reentry vehicles. This controller could make appropriate corrections to the trajectory of axisymmetric ballistic missiles as they approached the target. In 2000, scientists at the U.S. Naval Surface Warfare Research Center, including Chadwich, first applied mass moment technology to the guidance control of kinetic energy interception in anti-missile systems.

[0009] In summary, conventional drag sail spacecraft deorbit uncontrollably, posing a significant safety hazard. The introduction of mass moment technology can solve the problem of attitude adjustment difficulties for drag sail spacecraft. Summary of the Invention

[0010] The purpose of this invention is to provide an attitude control actuator for drag sail spacecraft, suitable for the deorbiting of 8U and medium-sized satellites. It not only helps to solve the problem of satellites failing to deorbit within a specified time after completing their mission and thus becoming space debris, and solves the problem of initial center of mass adjustment before satellite launch, but most importantly, it solves the long-standing problem of attitude control for drag sail spacecraft.

[0011] The technical solution to achieve the purpose of this invention is as follows: an attitude control actuator for a drag sail aircraft, comprising an XY displacement platform frame, a first movable plate, a second movable plate, a trapezoidal lead screw mechanism, a gear mechanism, a stepper motor, a travel limit switch, and a drive component. The stepper motor and driver are installed inside the platform frame. The upper second movable plate is fixedly connected to a moving block. The moving block is mounted on two lead screws with an included angle of 90°. Each lead screw is mounted on two bearings on both sides of the platform frame. Two parallel guide rails are installed on the upper and lower parts of the frame. A slider is fixed on the upper second movable plate. The gear mechanism is installed on one end of the stepper motor and the lead screw. The travel limit switch is fixed inside the frame. The gear mechanism transmits the motor power to the lead screw. The trapezoidal lead screw mechanism converts the rotation of the lead screw into the linear motion of the moving block. The first and second movable plates, fixed on the moving block, achieve linear motion in the X and Y directions through the guide rail slider, thereby adjusting the relative position of the drag sail.

[0012] Compared with the prior art, the significant advantages of this invention are:

[0013] (1) The present invention is small in size and light in weight, which fully meets the requirements of miniaturization and lightweighting of satellites, reduces the restrictions on the mass and space of other systems, and improves the functional density of satellites.

[0014] (2) This invention has a wide range of applications and can be applied to any small and medium-sized satellite platform. Its shape design makes full use of the space inside the satellite separation mechanism. It is installed outside the satellite and does not occupy the space inside the satellite. It is plug-and-play and does not affect the internal layout of the satellite.

[0015] (3) The present invention introduces two-dimensional movement at the mounting port between the drag sail shell and the main structure of the satellite, which can adjust the relative position of the drag sail and form a mass moment control configuration, thereby enabling active attitude control of the drag sail satellite, and making it possible for the drag sail spacecraft to be deorbited in a controlled manner.

[0016] (4) The present invention has array mounting holes designed in the first moving plate, which can be used to adjust the center of mass of the satellite in the pre-launch stage by utilizing the weight of the drag sail device itself.

[0017] (5) This invention is a standalone system that does not increase the lifespan requirements of other systems, nor is it affected by whether other systems are functioning properly. It ensures the reliability of the off-track system without interfering with other systems.

[0018] (6) The main frame structure of the present invention has good integrity and strong overall impact and vibration resistance, ensuring the normal operation of the effective control braking sail device.

[0019] (7) The working principle of this invention is simple and can be achieved by using common stepper motors, gears, trapezoidal lead screws, and slider guide rails.

[0020] (8) The present invention has a simple structure, good reliability, low processing cost, and strong practicality, and is very suitable for small and medium-sized satellites with fast response and short mission cycle. Attached Figure Description

[0021] Figure 1 This is a front view of the three-dimensional structure of the attitude control actuator for the drag sail aircraft of the present invention.

[0022] Figure 2 This is a three-dimensional structural diagram of the main frame of the drag sail attitude control actuator of the present invention.

[0023] Figure 3 This is a three-dimensional structural diagram of the second moving plate on the drag sail attitude control actuator of the present invention.

[0024] Figure 4 This is a three-dimensional structural diagram of the mounting position of the guide rail slider of the drag sail attitude control actuator of the present invention.

[0025] Figure 5 This is a front view of the trapezoidal lead screw mounting structure of the drag sail attitude control actuator of the present invention.

[0026] Figure 6 This is a front view of the three-dimensional structure of the gear mechanism of the drag sail attitude control actuator of the present invention.

[0027] Figure 7 This is a three-dimensional structural diagram of the travel limit switch installation of the present invention.

[0028] Figure 8 This is a three-dimensional schematic diagram of the installation of the stepper motor and drive components of the drag sail attitude control actuator of the present invention.

[0029] Figure 9 This is a schematic diagram of the satellite's coordinate system after the present invention is installed on the satellite.

[0030] Figure 10 This is a schematic diagram of the satellite's own system and the space inertial coordinate system. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings.

[0032] Combination Figures 1-10 A drag sail attitude control actuator is disclosed. Its main body occupies a space of 400mm×400mm×92mm. The first movable plate 1 is fixedly connected to the drag sail storage device 3, and the second movable plate 2 is fixedly connected to the leeward side of the satellite. While not occupying the space inside the satellite, it can control the relative position of the drag sail pressure center with the satellite, increase the atmospheric drag on the spacecraft, and thus accelerate the spacecraft to quickly leave the orbit.

[0033] The attitude control actuator of the drag sail aircraft includes a first moving plate 1, a second moving plate 2, a platform frame 3, two X-direction guide rails 4, two Y-direction guide rails 6, an X-direction lead screw 8, a Y-direction lead screw 11, a first driving gear 12, a second driving gear 20, a first driven gear 13, a second driven gear 21, a first stepper motor 14, a second stepper motor 18, a first driver 15, a second driver 19, a first moving block 9, a second moving block 10, an X-direction travel limit switch 16, an X-direction laser displacement sensor 17, a Y-direction travel limit switch 22, a Y-direction laser displacement sensor 23, two X-direction bearings 24, and two Y-direction bearings 25. A pair of X-direction sliders 5 are mounted on the X-direction guide rail 4, and a pair of Y-direction sliders 7 are mounted on the Y-direction guide rail 6. The first moving block 9 is mounted on the X-direction lead screw 8. An X-direction travel limit switch 16 and an X-direction laser displacement sensor 17 are located at one end of the X-direction lead screw within the frame. The travel of the first moving block 9 is controlled by the X-direction travel limit switch 16. The first moving block 9 is fixedly connected to the first moving plate 1. The second moving block 10 is mounted on the Y-direction lead screw 11. A Y-direction travel limit switch 22 and a Y-direction laser displacement sensor 23 are located at one end of the Y-direction lead screw 11 within the frame. The travel of the second moving block 10 is controlled by the Y-direction travel limit switch 22. The second moving block 10 is fixedly connected to the second moving plate 2.

[0034] The X-direction slider 5 is fixedly connected to the first moving plate 1, and the Y-direction slider 7 is fixedly connected to the second moving plate 2. Two X-direction guide rails 4 are fixed parallel to one side of the platform frame 3, and two Y-direction guide rails 6 are fixed parallel to the other side of the platform frame 3. The X-direction lead screw 8 is set along the X-direction central axis of the platform frame 3, and its two ends are connected to the platform frame 3 through X-direction bearings 24. The Y-direction lead screw 11 is set along the Y-direction central axis of the platform frame 3, and its two ends are connected to the platform frame 3 through Y-direction bearings 25. The X-direction lead screw 8 and the Y-direction lead screw 11 are perpendicular to each other, so that the moving blocks on the X-direction lead screw 8 and the Y-direction lead screw 11 do not interfere with each other when they move.

[0035] The first stepper motor 14, the second stepper motor 18, the first driver 15, and the second driver 19 are all installed within the platform frame 3. The first stepper motor 14 is connected to the first driver 15, and the second stepper motor 18 is connected to the second driver 19. The first drive gear 12 meshes with the first driven gear 13, connecting the first stepper motor 14 to the X-direction lead screw 8. The second drive gear 20 meshes with the second driven gear 21, connecting the second stepper motor 18 to the Y-direction lead screw 11.

[0036] The motion trajectories of the moving block and the slider on the same surface must be consistent.

[0037] Combination Figure 2 , Figure 3 , Figure 4 The first moving plate 1 has arrayed mounting holes, allowing for adjustment of the satellite's center of gravity during the pre-launch phase by adjusting the mounting position of the first moving plate 1. In operation, the moving block, along with a set of meshing drive and driven gears, forms a trapezoidal lead screw mechanism. This mechanism converts the rotation of the first stepper motor 14 and the second stepper motor 18 into linear motion. Because the first moving plate 1 is fixed to the first moving block 9, it moves linearly under the constraint of the X-direction slider 5 and guide rail 4, thereby changing the relative position of the drag sail device and the satellite, and further altering the pressure center position. Similarly, the second moving plate 2, fixed to the second moving block 10, controls the entire moving platform and the relative position of the drag sail device and the satellite, thus expanding the controllable space and better utilizing the torque generated by aerodynamic drag. Meanwhile, an X-direction travel limit switch 16 and a Y-direction travel limit switch 22 are designed at the end of the travel of the first moving plate 1 and the second moving plate 2. During the control process, when the first moving plate 1 or the second moving plate 2 moves to its farthest travel, it will touch the X-direction travel limit switch 16 or the Y-direction travel limit switch 22 installed on the inside of the platform frame 3, and then will prevent the first moving plate 1 or the second moving plate 2 from continuing to move forward.

[0038] Combination Figure 2 , Figure 5 , Figure 8 The platform frame 3 serves as the main frame of the entire system. A pair of X-direction guide rails 4 with an included angle of 90° are installed on the upper surface of the platform frame 3, and a pair of Y-direction guide rails 6 with an included angle of 90° are installed on the lower surface of the platform frame 3. The spatial dimensions, mass, and strength of the platform frame 3 are important indicators of the entire device. The spatial dimensions and mass of the platform frame 3 are optimized to ensure the platform's performance, aesthetics, and design integrity.

[0039] Combination Figure 1 , Figure 5 A trapezoidal lead screw mechanism is formed by a lead screw, a moving block, and a set of meshing driving and driven gears. This mechanism primarily converts the rotation of the first stepper motor 14 and the second stepper motor 18 into linear motion. The trapezoidal lead screw, model T8, is characterized by its small size, high precision, and strong self-locking capability. In the design, the distance between the X-direction lead screw 8 and the Y-direction lead screw 11 is minimized to reduce the overall height of the device. The two ends of the X-direction lead screw 8 are mounted on a pair of X-direction ball bearings 24, and the two ends of the Y-direction lead screw 11 are mounted on a pair of Y-direction ball bearings 25. The X-direction ball bearings 24 and Y-direction ball bearings 25 are mounted on the platform frame 3 and locked by the X-direction lead screw 8, Y-direction lead screw 11, X-direction bearing cover 26, and Y-direction bearing cover 27 to ensure that this structure will not loosen during satellite launch and operation.

[0040] Combination Figure 6 , Figure 8 A set of meshing driving and driven gears constitutes a gear mechanism, which employs a 1:1 gear ratio. Taking the X direction as an example, the first driving gear 12 is fixed to the first stepper motor 14 via a keyway, and the first driven gear 13 is fixed to the first lead screw 8 via a keyway. The first stepper motor 14, installed within the platform, transmits the power to the first lead screw 8 in a 1:1 ratio through the first driving gear 12 and the first driven gear 13.

[0041] Combination Figure 7 , Figure 8 To ensure that the first moving plate 1 and the second moving plate 2 do not exceed their travel limits during operation, an X-direction travel limit switch 16 and a Y-direction travel limit switch 22 are installed in the X-direction lead screw 8 and Y-direction lead screw 11 within the platform frame 3. An X-direction laser displacement sensor 17 and a Y-direction laser displacement sensor 23 can monitor the positions of the first moving plate 1 and the second moving plate 2 in real time, forming a control loop to further improve system accuracy.

[0042] Combination Figure 1 , Figure 6 , Figure 7 , Figure 8 The first stepper motor 14 and the second stepper motor 18 are both 42-type stepper motors and their drivers. The first stepper motor 14 and the second stepper motor 18 are fixed to the inside of the platform frame 3 with screws. For optimal installation position and shortest wiring distance, the first driver 15 and the second driver 19 are fixed to the inside of the platform frame 3 with screws.

[0043] Combination Figure 1 , Figure 8 The power inlet of the entire platform will be connected to the satellite's main system via the second movable plate 2, facilitating use during the deorbiting phase at the end of the satellite's lifespan. The entire platform has a power output of approximately 5 watts, which is within an acceptable power range for small to medium-sized satellites.

[0044] Job Description

[0045] A drag sail attitude control actuator for a CubeSat is fixed to the leeward side of a CubeSat. A drag sail device is mounted on a first movable plate 1. Before launch, the satellite's center of gravity can be adjusted using the mounting holes on the first movable plate 1 and the mounting position of the drag sail device. The entire device is then fixed to the bottom of the satellite through through holes in a second movable plate 2.

[0046] X-direction slider 5 is fixed to the first moving plate 1, and Y-direction slider 7 is fixed to the second moving plate 2. The first moving block 9 is fixed to the first moving plate 1 with four screws, and the second moving block 10 is fixed to the second moving plate 2 with four screws. The first stepper motor 14, the second stepper motor 18, the first driver 15, and the second driver 19 are fixed inside the platform frame 3 with screws. The transmission of the first stepper motor 14 is transmitted through the first driving gear 12 at its shaft end to the first driven gear 13 at the end of the X-direction lead screw 8. The X-direction lead screw 8 is mounted on the X-direction bearing 24. The transmission of the second stepper motor 18 is transmitted through the second driving gear 20 at its shaft end to the second driven gear 21 at the end of the Y-direction lead screw 11. The Y-direction lead screw 11 is mounted on the Y-direction bearing 25.

[0047] After the CubeSat completes its mission in orbit, it receives the command to deploy the drag sail and, after deploying the drag sail, the actuator begins to operate. Taking X-direction movement as an example, the first stepper motor 14 controls the relative position of the satellite and the actuator in the X-direction through the first driving gear 12, the first driven gear 13, the X-direction lead screw 8, the first moving block 9, and the first moving plate 1, thus achieving attitude control of the drag sail. This increases the cross-sectional area in the velocity direction during satellite flight, increases the air resistance experienced by the CubeSat, and accelerates the satellite's departure from orbit.

[0048] The working principle of this institution is as follows:

[0049] Combination Figure 9 , Figure 10 As shown, with the satellite's center of mass as the origin of the body coordinate system, and both the satellite and the drag sail considered as rigid bodies, O E Point O is the origin of the geocentric inertial frame of reference. M The centroid of the satellite body is defined by vector R. b With R s In an inertial frame of reference, and with vector P described in the satellite's own frame, the translational dynamic equations of the system can be written as follows:

[0050]

[0051]

[0052] Where, m b For the mass of the satellite itself, m s Let m be the mass of the drag sail, and the total mass of the system be m. T =m b +m s Vo These correspond to the velocity vector and acceleration vector of the origin of the body coordinate system in the inertial coordinate system, respectively. bi Let ω be the coordinate transformation matrix from the satellite's intrinsic frame to the geocentric inertial frame. BThis is the expression for the angular velocity of the satellite relative to the inertial frame within the system itself. For ω B The first derivative with respect to time is the angular acceleration, where p is the radius vector of the actuator's center of mass in the body coordinate system. Let p be the first derivative of time, i.e., the velocity vector. F is the second derivative of p with respect to time, i.e., the acceleration vector. d G is the aerodynamic force on the sail surface, G is the gravitational force on the entire satellite system, G is the Earth's gravitational constant, M is the Earth's mass, and R is the satellite's position vector in the inertial frame.

[0053] The rotational dynamics of the system can be expressed as:

[0054]

[0055] Where, m b For the mass of the satellite itself, m s For the drag sail mass, I b Let I be the inertial tensor of the satellite body relative to its own center of mass. s Let A be the inertial tensor of the drag sail relative to its own center of mass. bi This is the coordinate transformation matrix from the satellite's intrinsic frame to the geocentric inertial frame. Let ω be the acceleration vector of the origin of the body coordinate system in the inertial coordinate system. B This is the expression for the angular velocity of the satellite relative to the inertial frame within the system itself. For ω B The first derivative with respect to time is the angular acceleration, where p is the position vector of the actuator's center of mass in this system. Let p be the first derivative of p with respect to time, i.e., the velocity vector. M is the second derivative of p with respect to time, i.e., the acceleration vector; p This represents the disturbance torque experienced by the system.

[0056] After simplifying the above two equations, the drag sail satellite system model can be obtained as follows:

[0057]

[0058] Among them, I c Let m be the inertial tensor of the satellite relative to its own center of mass after this actuator is installed. The mass of the entire system is m. T =m b +m s p is the centroid position vector of the actuator in this system. Let p be the first derivative of p with respect to time, i.e., the velocity vector. Let ω be the second derivative of p with respect to time, i.e., the acceleration vector. BFor the expression of the angular velocity of the satellite relative to the inertial frame within this system, M p The disturbance torque experienced by the system, For ω B The first derivative with respect to time, i.e., angular acceleration, F d This refers to the aerodynamic force acting on the sail.

[0059] This actuator can change the position p of the mass block and the aerodynamic force F by changing the positions of the first moving plate 1 and the second moving plate 2. d This generates a control torque, and therefore, by designing a reasonable control algorithm, the attitude control of the satellite can be achieved through this actuator.

[0060] In summary, the drag sail attitude control actuator of this invention has a simple structure, low manufacturing cost, good integrity, high reliability, small size, and light weight, fully meeting the miniaturization and lightweight requirements of deorbiting devices for small and medium-sized satellites. Furthermore, its modularity and independence do not affect the operation of other satellite systems, and it does not impose higher requirements on the lifespan of other subsystems. Moreover, the drag sail attitude control actuator of this invention is installed externally on the satellite, without affecting the internal layout, making it suitable for low-cost, short-cycle, high-functional-density CubeSats and small and medium-sized satellites.

Claims

1. A drag sail aircraft attitude control actuator, characterized in that: Includes a first moving plate (1), a second moving plate (2), a platform frame (3), an X-direction lead screw (8), a Y-direction lead screw (11), a first driving gear (12), a second driving gear (20), a first driven gear (13), a second driven gear (21), a first stepper motor (14), a second stepper motor (18), a first driver (15), a second driver (19), a first moving block (9), a second moving block (10), an X-direction travel limit switch (16), an X-direction laser displacement sensor (17), a Y-direction travel limit switch (22), a Y-direction laser displacement sensor (23), two X-direction bearings (24), two Y-direction bearings (25), two X-direction guide rails (4), and two Y-direction guide rails (6); the X-direction guide rails (4) are equipped with... There is a pair of X-direction sliders (5), and a pair of Y-direction sliders (7) on the Y-direction guide rail (6); the first moving block (9) is set on the X-direction lead screw (8), the X-direction travel limit switch (16) and the X-direction laser displacement sensor (17) are set on one end of the X-direction lead screw (8) in the frame, and the travel limit switch (16) controls the travel of the first moving block (9), and the first moving block (9) is fixedly connected to the first moving plate (1); the second moving block (10) is set on the Y-direction lead screw (11), the Y-direction travel limit switch (22) and the Y-direction laser displacement sensor (23) are set on one end of the Y-direction lead screw (11) in the frame, and the travel of the second moving block (10) is controlled by the Y-direction travel limit switch (22), and the second moving block (10) is fixedly connected to the second moving plate (2); The X-direction slider (5) is fixedly connected to the first moving plate (1), the Y-direction slider (7) is fixedly connected to the second moving plate (2), the two X-direction guide rails (4) are fixedly parallel to one side of the platform frame (3), and the two Y-direction guide rails (6) are fixedly parallel to the other side of the platform frame (3); the X-direction screw (8) is set along the X-direction central axis of the platform frame (3), and its two ends are connected to the platform frame (3) through the X-direction bearing (24); the Y-direction screw (11) is set along the Y-direction central axis of the platform frame (3), and its two ends are connected to the platform frame (3) through the Y-direction bearing (25); the X-direction screw (8) and the Y-direction screw (11) are perpendicular to each other, so that the moving blocks on the X-direction screw (8) and the Y-direction screw (11) do not interfere with each other when they move. The first stepper motor (14), the second stepper motor (18), the first driver (15), and the second driver (19) are all installed inside the platform frame (3). The first stepper motor (14) is connected to the first driver (15), and the second stepper motor (18) is connected to the second driver (19). The first drive gear (12) meshes with the first driven gear (13), and the first stepper motor (14) is connected to the X-direction lead screw (8) through the first drive gear (12) and the first driven gear (13). The second driving gear (20) meshes with the second driven gear (21), and the second stepper motor (18) is connected to the Y-direction lead screw (11) through the second driving gear (20) and the second driven gear (21); The motion trajectories of the moving block and the slider on the same surface must be consistent.

2. The attitude control actuator for a drag sail aircraft according to claim 1, characterized in that: The first moving plate (1) has array mounting holes. During the pre-launch phase, the center of mass of the entire satellite can be adjusted by adjusting the mounting position of the first moving plate (1). In the working state, the moving block and a set of meshing active and driven gears form a trapezoidal screw mechanism. The trapezoidal screw structure converts the rotation of the first stepper motor (14) and the second stepper motor (18) into linear motion. Since the first moving plate (1) is fixed on the first moving block (9), the first moving plate (1) moves linearly under the constraint of the X-direction slider (5) and the X-direction guide rail (4), thereby changing the relative position of the drag sail device and the satellite, and further changing the position of the pressure center. Similarly, the second moving plate (2) The control of the entire moving platform and the relative position of the drag sail device and the satellite is fixed on the second moving block (10), thereby expanding the controllable space and making better use of the torque formed by aerodynamic drag. At the same time, X-direction travel limit switch (16) and Y-direction travel limit switch (22) are designed at the end of the stroke of the first moving plate (1) and the second moving plate (2). During the control process, when the first moving plate (1) or the second moving plate (2) moves to the farthest stroke, it will touch the X-direction travel limit switch (16) or the Y-direction travel limit switch (22) installed on the inside of the platform frame (3), and then will prevent the first moving plate (1) or the second moving plate (2) from continuing to move forward.

3. The attitude control actuator for a drag sail aircraft according to claim 2, characterized in that: A set of meshing drive gears and driven gears constitutes a gear mechanism, and the gear mechanism adopts a pair of 1:1 gear transmission coefficients; in the X direction, the first drive gear (12) is fixed to the first stepper motor (14) through a keyway, and the first driven gear (13) is fixed to the first lead screw (8) through a keyway; the first stepper motor (14) installed in the platform will transmit the transmission 1:1 to the first lead screw (8) through the first drive gear (12) and the first driven gear (13).

4. The attitude control actuator for a drag sail aircraft according to claim 1, characterized in that: Taking the satellite's center of mass as the origin of its coordinate system, and considering both the satellite and the drag sail as rigid bodies. Point is the origin of the geocentric inertial frame of reference. The centroid of the satellite body; where the vector and In an inertial frame of reference, a vector In the description of the satellite's core system, the drag sail satellite system model is as follows: ； in, This is the inertial tensor of the satellite relative to its own center of mass after the installation of this actuator. The mass of the satellite itself is, The mass of the drag sail, the mass of the entire system , This is the centroid position vector of the actuator in this system. for The first derivative with respect to time is the velocity vector. for The second derivative with respect to time is the acceleration vector. This is the expression for the angular velocity of the satellite relative to the inertial frame within the system itself. for The first derivative with respect to time is angular acceleration. The disturbance torque experienced by the system, The aerodynamic force acting on the sail surface; The actuator changes the position of the first moving plate (1) and the second moving plate (2), thereby altering... and This generates a control torque, which allows the satellite's attitude to be controlled via this actuator.

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