Hollow-core magnetic torquer for spacecraft

Abstract

The invention relates to the technical field of spacecraft attitude control, in particular to a hollow-core magnetic torquer for a spacecraft, which comprises a coil body, the coil body comprises an inner-layer coil, a middle-layer coil and an outer-layer coil, a base is mounted at the bottom of the outer-layer coil, and screw rods are mounted at the positions, close to the two ends, of the top of the base through shaft seats. The inner-layer coil is connected with the lead screw at one end of the base, the outer-layer coil is connected with the lead screw at the other end of the base, and a motor driving the lead screws to rotate is mounted at the top of the base and corresponds to the lead screws. According to the invention, the coils are arranged into three groups, and two groups of coils are arranged to be capable of relatively axially moving, so that the magnetic field intensity can be indirectly changed by changing the magnetic field superposition amount of the coils on the premise that the input current is fixed, and therefore, the magnitude of the output torque can be changed, and compared with the existing pulse width modulation control mode, the output torque can be changed. An additional control mode can be supplemented and replaced, and a standby control scheme is provided for the magnetic torquer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of spacecraft attitude control, and particularly relates to an air-core magnetic torque device for a spacecraft. BACKGROUND

[0002] The magnetic torque device is one of the core execution mechanisms of the spacecraft attitude control system, and generates a control torque through interaction with the geomagnetic field to achieve attitude adjustment and momentum management. The magnetic torque device generally has an air-core coil and a core coil. The coil of the core coil is densely wound on a ferromagnetic core column, while the air-core coil does not have a core column. Compared with the core coil, the air-core coil has the advantages of fast demagnetization and no need for demagnetization.

[0003] The torque control of the magnetic torque device is achieved by passing a certain current through the coil to generate a magnetic field, which interacts with the geomagnetic field to generate a torque. There are various schemes for adjusting the current size, such as resistance adjustment, transformer adjustment, semiconductor device adjustment, pulse width modulation, current feedback control, and silicon controlled rectifier adjustment method. Among them, the pulse width modulation control method is used in the magnetic torque device. The magnetic torque control command of the on-board central machine generates a corresponding duty cycle PWM pulse. These pulses are loaded onto the H-bridge drive circuit for power amplification, and then output to the magnetic torque device. At the same time, the current detection processing circuit placed in the loop of the magnetic torque device collects the current on the magnetic torque device and converts it into current telemetry data to provide to the magnetic torque controller for closed-loop control.

[0004] Pulse width modulation has the advantages of energy saving and high precision, but still has problems of electromagnetic interference, current ripple, and PWM signal harmonic influence. Therefore, a complex circuit and an optimized control algorithm need to be set, which to some extent reduces the stability of the entire system. When the current size adjustment fails, it directly leads to the inability to provide satellite attitude control requirements. The existing magnetic torque device lacks alternative and supplementary control schemes. SUMMARY

[0005] The present application specifically adopts the following technical solutions to achieve the above-mentioned purposes. An air-core magnetic torque device for a spacecraft, comprising a coil body, the coil body comprising an inner coil, a middle coil, and an outer coil, the bottom of the outer coil being provided with a base, the top of the base being provided with a lead screw at both ends through a shaft seat, the inner coil being connected with the lead screw at one end of the base, the outer coil being connected with the lead screw at the other end of the base, and the top of the base being provided with a motor driving the lead screw at the position of the lead screw.

[0006] Furthermore, the coil body is fixed by encapsulation with epoxy resin. Iron-core coils can be fixed around an iron core, thus achieving good fixation without epoxy resin. When using enameled wire, the required insulation is also present. Air-core coils rely on epoxy resin to maintain the stability of the wound coil and prevent loosening.

[0007] Furthermore, the inner, middle, and outer coils have the same length, wire diameter, number of turns, and winding density. Equal main parameters for the inner, middle, and outer coils simplify the control of coil displacement based on magnetic field strength requirements. Alternatively, the coils can be configured as complementary layers. When the inner, middle, and outer coils completely overlap, the overall magnetic field is uniform. When the inner and outer coils move away from the middle coil, this complementarity can also be used to control magnetic field uniformity while reducing magnetic field strength.

[0008] Furthermore, the inner coil is fixed by an inner beam and an end frame, with a fixing plate fixed to the end frame. The fixing plate is threadedly connected to a lead screw at a corresponding position. The outer coil is fixed by an outer beam and an end ring, with a fixing plate fixed to the end ring. The fixing plate is threadedly connected to a lead screw at a corresponding position. The middle coil is fixed by a fixing bracket at one end. The beam, end frame, and end ring are all used to connect the coil to the fixing plate, ensuring that the coil can move stably and reliably when the fixing plate moves. Simultaneously, the beam, end frame, and end ring, in conjunction with each other, provide structural support for the inner and outer coils.

[0009] Furthermore, a housing is installed on the outside of the base. The base, inner coil, middle coil, and outer coil are all installed inside the housing. Reinforcing ribs are fixed on the housing in a crisscross pattern. The reinforcing ribs increase the structural strength of the housing, which allows the thickness of the housing to be reduced, thus minimizing the weight of the entire magnetic torquer while ensuring strength.

[0010] Furthermore, a bottom bracket is fixed at the top center of the base, supporting the corresponding beam rod. A top support rod is fixed inside the housing, also supporting the corresponding beam rod. The fixing frame is fixed to the housing. Both the bottom bracket and the top support rod are used to constrain and fix the entire coil in a weightless environment, in conjunction with the housing.

[0011] Furthermore, the end ring and end bracket at the front lead screw position of the base are arranged sequentially from front to back, while the end bracket, fixing bracket, and end ring at the rear lead screw position of the base are arranged sequentially from back to front. The fixing plate two at the front position of the outer coil is connected to the lead screw at the corresponding position, and the fixing plate one at the rear position of the inner coil is connected to the lead screw at the corresponding position. This differentiated arrangement avoids obstruction during the movement of the inner and outer coils. Of course, this arrangement only applies to the structure of the end ring, fixing bracket, and end bracket; the structure of the end ring, fixing bracket, and end bracket can be modified to fix the respective coils at different angles or positions without affecting the movement of the inner and outer coils.

[0012] Furthermore, a diagonal brace is fixed to the side of the base at the position corresponding to the fixing bracket, and the fixing bracket at the corresponding position is fixed to the diagonal brace. The diagonal brace provides support for the fixing bracket at that position, and at the same time, the setting of the diagonal brace increases the bottom area of ​​the entire shell, indirectly improving the stability of the shell after installation.

[0013] Furthermore, a connector is installed on the housing, and multiple limiting bent rods are fixed on the inner side of the housing near the connector. Depending on the number of layers of the coil winding, the connectors can be set in different directions and in different numbers. When the two leads of the coil are pulled out from the same direction, only one input and one output connector need to be set at that position, which can be freely adjusted according to specific circumstances.

[0014] The beneficial effects of this invention are as follows: 1. This invention sets up three groups of coils, with two of them being able to move relative to each other axially. Under the premise of a fixed input current, the magnetic field strength can be indirectly changed by changing the superposition of the magnetic field of the coils, thereby changing the magnitude of the output torque. This provides an additional control method that can be supplemented and replaced by the existing pulse width modulation control method, thus providing a backup control scheme for the magnetic torque device.

[0015] 2. In this invention, the cooperation of a lead screw and a fixed plate, and the connection of the beam, end plate and end ring, realize the movement of the inner and outer coils, which is suitable for the weightless environment of space and can provide continuous and stable control.

[0016] 3. In this invention, in addition to being supported by the beam, end plate and end ring, each layer of coil is also fixed by epoxy resin encapsulation. This ensures the stability of the coil after winding and provides reliable connection support for the beam.

[0017] 4. The housing in this invention uses reinforcing ribs to enhance its structural strength, thereby reducing the housing thickness and weight, and providing some weight compensation for the newly added motor, lead screw and related components. Attached Figure Description

[0018] Figure 1This is a perspective view of the present invention; Figure 2 This is an axial sectional view of the present invention; Figure 3 This is a radial sectional view of the present invention; Figure 4 This is a schematic diagram of the interior of the housing in this invention; Figure 5 This is a schematic diagram of the end frame arrangement in this invention; Figure 6 This is a schematic diagram of the end ring configuration in this invention; Figure 7 This is a schematic diagram of the connection between the fixed plate 2 and the lead screw in this invention; Figure 8 This is an enlarged view of the inner coil, middle coil, and outer coil in this invention; Figure 9 This is a schematic diagram of the structural arrangement of the coil body in this invention.

[0019] Reference numerals in the attached diagram: 1. Inner coil; 11. Beam rod one; 12. End frame; 13. Fixing plate one; 2. Middle coil; 21. Fixing frame; 3. Outer coil; 31. Beam rod two; 32. End ring; 33. Fixing plate two; 4. Base; 41. Lead screw; 42. Shaft seat; 43. Motor; 44. Diagonal brace; 45. Bottom bracket; 5. Housing; 51. Front and rear housing covers; 52. Limiting bent rod; 53. Top support rod; 54. Reinforcing rib; 6. Connector; 100. Coil body; 101. Epoxy resin; 102. Coil lead wire. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0021] This application provides a hollow magnetic torque converter for spacecraft, mainly addressing the problem that current magnetic torque converters rely solely on changing the magnitude of the input current to adjust the magnetic field strength, lacking backup control schemes and unable to continue providing satellite attitude control functions in the event of problems. The following technical solution is provided, which will be discussed in conjunction with... Figures 1-9 Please provide a detailed explanation: A hollow magnetic torque generator for spacecraft includes an inner coil 1, a middle coil 2, and an outer coil 3. The inner coil 1, the middle coil 2, and the outer coil 3 are all composed of a multi-layered densely wound coil body 100. Epoxy resin 101 is disposed on the outside of the coil body 100, and the coil body 100 is fixed by the epoxy resin 101. The coil leads 102 at both ends of the coil body 100 pass through the epoxy resin 101 at the corresponding positions. The coil body 100 is wound with enameled wire, and can be stacked during winding. Inner coil 1, middle coil 2 and outer coil 3 are stacked sequentially from the inside to the outside. Inner coil 1, middle coil 2 and outer coil 3 are not connected or fixed to each other. The length, wire diameter, number of turns and winding density of inner coil 1, middle coil 2 and outer coil 3 are all equal. A base 4 is installed at the bottom of outer coil 3. The length of base 4 is greater than the length of outer coil 3. A lead screw 41 is installed at both ends of the top of the base 4. The inner coil 1 is connected to the lead screw 41 at one end of the base 4, and the outer coil 3 is connected to the lead screw 41 at the other end of the base 4. A bearing seat 42 is fixed at both ends of the lead screw 41 on the top of the base 4. The two ends of the lead screw 41 are installed with the bearing seat 42 at the corresponding positions. A motor 43 is installed at one end of the lead screw 41 near the middle of the base 4. The output end of the motor 43 is fixedly connected to the lead screw 41 at the corresponding position. The motor 43 is a stepper motor. A connector 6 is installed at both ends of the side of the base 4. The coil leads 102 at both ends of the inner coil 1, the middle coil 2, and the outer coil 3 are electrically connected to the connector 6 at the corresponding positions.

[0022] During normal operation, the existing closed-loop pulse width control method is still used to generate a magnetic field of the required strength by applying a certain current. The magnetic field interacts with the Earth's magnetic field to generate torque. When selecting the backup control scheme, it is recommended to divide the power supply of the coil body 100 into two paths. One path is connected to the existing PWM circuit to perform the existing normal current input control. The other path does not set current or voltage regulation, but directly supplies power. This circuit is equivalent to the backup circuit of the backup control scheme. When the current input under the closed-loop pulse width control becomes unstable or fails, the backup scheme can be switched to for control. When using this hollow magnetic torque device, three sets are set along the X, Y, and Z axes of the satellite. Before starting the backup control scheme, the closed-loop pulse width control is stopped first, and then the motor 43 is controlled to work. First, a reset is performed. The motor 43 drives the lead screw 41 at the corresponding position to rotate. By using the connection between the two lead screws 41 and the inner coil 1 and the outer coil 3 respectively, the inner coil 1 and the outer coil 3 are moved outward along the lead screw 41 at the corresponding position, so that there is only half a length overlap between the inner coil 1 and the middle coil 2 and between the middle coil 2 and the outer coil 3. The reset can also be performed during installation. First, based on the satellite's required attitude direction and the magnetic field strength generated by the input current of the magnetic torque device at that position, the onboard central control unit determines whether the current magnetic field strength is greater than or less than the required strength. If the current magnetic field strength of the magnetic torque device is greater than the required strength, the control motor 43 is activated, driving the lead screw 41 to rotate. This pulls the inner coil 1 and the outer coil 3 further outward, reducing the overlap length between the inner coil 1 and the middle coil 2, and between the middle coil 2 and the outer coil 3. This increases the coil spacing within the entire magnetic field, thereby reducing the magnetic field strength. Simultaneously, the overlap area between the inner coil 1 and the outer coil 3 and the middle coil 2 decreases, resulting in a reduction in the superposition of their magnetic fields. This positional relationship also leads to an uneven magnetic field distribution. The magnetic field is strongest in the overlapping areas of the inner coil 1 and the middle coil 2, and in the overlapping areas of the middle coil 2 and the outer coil 3, while the magnetic field is weakest in the non-overlapping areas. This uneven magnetic field also reduces the magnitude of the torque provided. Thus, by adjusting the amount of coil overlap, the magnitude of the magnetic field is changed, thereby indirectly adjusting the output torque.

[0023] In some embodiments, multiple equally spaced beams 11 are provided on the inner side of the inner coil 1. End frames 12 are installed at both ends of each beam 11, and the multiple beams 11 are fixed to the end frames 12. A downward-facing fixing plate 13 is fixed to the bottom of the end frame 12 at one end of the inner coil 1. A hole is opened on the fixing plate 13 corresponding to the position of the lead screw 41. The lead screw 41 passes through the hole and is threadedly connected to the fixing plate 13. Multiple equally spaced beams 2 31 are provided on the outer side of the outer coil 3. Multiple beams 2 31 are provided at both ends of each beam 2 31. An end ring 32 is installed, and multiple beam rods 31 are fixed to the end ring 32. A downward fixing plate 33 is fixed to the bottom of the end ring 32 at one end of the outer coil 3. A hole is opened on the fixing plate 33 corresponding to the position of the lead screw 41. The lead screw 41 passes through the hole and is threaded to the fixing plate 33. Multiple fixing brackets 21 are installed on the end of the middle coil 2 corresponding to the direction of the fixing plate 13. A diagonal brace 44 is fixed on the side of the base 4 corresponding to the position of the fixing bracket 21. The fixing bracket 21 is fixed to the diagonal brace 44 at the corresponding position.

[0024] The inner coil 1, middle coil 2, and outer coil 3 are all encapsulated with epoxy resin 101, which provides a certain degree of structural stability and strength. Beam rod 11 and beam rod 31 are provided to increase the structural strength and stability of the inner coil 1 and outer coil 3. The middle coil 2 is supported by the inner coil 1 and outer coil 3, and the position of the middle coil 2 can be fixed by using a fixing bracket 21.

[0025] In some embodiments, a housing 5 is installed on the outside of the base 4. The base 4, inner coil 1, middle coil 2 and outer coil 3 are all installed inside the housing 5. The housing 5 has openings at both ends, and front and rear covers 51 are installed at the opening positions. The plug 6 is installed on the housing 5 near the front and rear covers 51. The front and rear covers 51 have openings corresponding to the positions of the plug 6. Multiple reinforcing ribs 54 with equal spacing are fixed on the housing 5. The multiple reinforcing ribs 54 are arranged in a crisscross pattern. Multiple limiting bent rods 52 are fixed on the inner side of the housing 5 near the position of the plug 6. The wires between the plug 6 and the coil lead 102 are routed around the inner side of the limiting bent rods 52. The limiting bent rods 52 constrain the wires to prevent them from becoming loose and messy.

[0026] The housing 5 provides shielding protection for the entire magnetic torquer, reducing external influences. To avoid affecting the magnetic field of the coil, the housing 5, beam 11, end frame 12, fixing plate 13, fixing frame 21, beam 2 31, end ring 32, and fixing plate 2 33 are all made of non-magnetic metal or non-metallic materials. Considering the high requirements of the satellite for payload weight, in addition to using lightweight materials to control the weight, the thickness of the housing 5 can also be further controlled. The strength after the thickness is reduced is reinforced by the crisscrossing reinforcing ribs 54. Based on the weight increase caused by the addition of a series of components such as motor 43 and lead screw 41, the weight of other parts is reduced to compensate for the overall weight.

[0027] In some embodiments, a base bracket 45 is fixed at the top center of the base 4, and the top of the base bracket 45 abuts against the corresponding beam rod 31. A top support rod 53 is fixed at the top of the housing 5 at the position corresponding to the beam rod 31, and the top support rod 53 abuts against the corresponding beam rod 31. The end of the fixing bracket 21 outside the position of the diagonal brace 44 is fixed to the housing 5.

[0028] Once the satellite is launched into orbit, it is in a state of complete weightlessness. At this time, the outer coil 3 may move at different radial angles. Therefore, the top support rod 53 and the bottom support 45 are set for additional support to ensure that the entire coil is not prone to unnecessary movement.

[0029] In some embodiments, the end ring 32 and end bracket 12 at the front lead screw 41 position of the base 4 are arranged sequentially from front to back, and the end bracket 12, fixing bracket 21, and end ring 32 at the rear lead screw 41 position of the base 4 are arranged sequentially from back to front. The fixing plate 2 33 at the front position of the outer coil 3 is connected to the lead screw 41 at the corresponding position, and the fixing plate 13 at the rear position of the inner coil 1 is connected to the lead screw 41 at the corresponding position.

[0030] The lead screw 41 on the front side is connected to the outer coil 3, so the outer coil 3 can move forward along the lead screw 41. The lead screw 41 on the rear side is connected to the inner coil 1, so the inner coil 1 can move backward along the lead screw 41. The end ring 32 is offset from the fixing frame 21 to avoid affecting the forward movement of the outer coil 3. The end frame 12 is located on the innermost side. After the fixing plate 13 is offset from the end ring 32, it will not affect the backward movement of the inner coil 1.

[0031] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hollow core magnetic torque wrench for a spacecraft comprising a coil body (100) characterised in that, The coil body (100) comprises an inner coil (1), a middle coil (2) and an outer coil (3), the bottom of the outer coil (3) is provided with a base (4), the top of the base (4) is provided with a lead screw (41) through an axle seat (42) at both ends, the inner coil (1) is connected with the lead screw (41) at one end of the base (4), the outer coil (3) is connected with the lead screw (41) at the other end of the base (4), and the top of the base (4) is provided with a motor (43) for driving the rotation of the lead screw (41) at the position corresponding to the lead screw (41).

2. A hollow magnetic momenter for a spacecraft according to claim 1, wherein, The coil body (100) is packaged and fixed by the epoxy resin (101).

3. A hollow magnetic momenter for a spacecraft according to claim 2, wherein, The lengths, wire diameters, turn numbers and winding densities of the inner coil (1), the middle coil (2) and the outer coil (3) are equal.

4. A hollow magnetic momenter for a spacecraft according to claim 1, wherein The inner coil (1) is fixed by an inner beam (11) and an end frame (12), the end frame (12) is fixed with a fixed plate (13), the fixed plate (13) is threadedly connected with the lead screw (41) at the corresponding position, the outer coil (3) is fixed by an outer beam (31) and an end ring (32), the end ring (32) is fixed with a fixed plate (33), the fixed plate (33) is threadedly connected with the lead screw (41) at the corresponding position, and the middle coil (2) is fixed by a fixed frame (21) at one end.

5. A hollow magnetic momenter for a spacecraft according to claim 4, wherein, The base (4) is provided with a shell (5) on the outer side, and the base (4), the inner coil (1), the middle coil (2) and the outer coil (3) are all arranged in the shell (5), and the shell (5) is fixed with a plurality of reinforcing ribs (54) arranged in a crisscross manner.

6. A hollow magnetic momenter for a spacecraft according to claim 5, wherein, The base (4) is fixed with a bottom bracket (45) at the middle position of the top, which abuts against and supports the corresponding beam (31), the top of the shell (5) is fixed with a top support rod (53) corresponding to the position of the beam (31), and the fixed frame (21) is fixed to the shell (5).

7. A hollow magnetic momenter for a spacecraft as defined in claim 4, wherein, The end ring (32) and the end frame (12) at the position of the lead screw (41) on the front side of the base (4) are arranged from front to back, the end frame (12), the fixed frame (21) and the end ring (32) at the position of the lead screw (41) on the rear side of the base (4) are arranged from back to front, the fixed plate (33) at the position of the lead screw (41) on the front side of the outer coil (3) is connected with the lead screw (41) at the corresponding position, and the fixed plate (13) at the position of the lead screw (41) on the rear side of the inner coil (1) is connected with the lead screw (41) at the corresponding position.

8. A hollow magnetic momenter for a spacecraft according to claim 6, wherein, The shell (5) is provided with a plug (6), and a plurality of limiting bent rods (52) are fixed to the inner side of the shell (5) close to the plug (6).

9. A hollow magnetic momenter for a spacecraft as defined in claim 5, wherein, ​

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