Electromagnetic reaction wheel

Abstract

An electromagnetic reaction wheel includes an annular tube, a plurality of coil assemblies, a magnetic assembly, and a controller. The annular tube has a cavity. Each of the plurality of coil assemblies includes a plurality of first coils and a plurality of second coils. The plurality of first coils is disposed on an outer surface of the annular tube. The plurality of second coils is distant from the annular tube. The plurality of first coils and the plurality of second coils are arranged in Halbach array sequence. The magnetic assembly is movably disposed in the cavity of the annular tube. The controller is electrically connected to the plurality of coil assemblies. The controller is adapted to control the plurality of first coils and / or the plurality of second coils to be energized or denergized, so as to drive the magnetic assembly to move in the cavity with respect to the annular tube.

Description

[Technical Field]

[0001] The present invention relates to a reaction wheel, and more particularly to an electromagnetic reaction wheel. [Previous Technology]

[0002] A reaction wheel is a device primarily used in spacecraft, such as satellites. Existing reaction wheels mainly consist of a motor, a flywheel, and bearings. The motor drives the flywheel to rotate, generating angular momentum, causing the satellite to move in the opposite direction due to the corresponding reaction force, thus adjusting the satellite's attitude in space. However, after long-term operation, the bearings of the reaction wheel inevitably wear down. This wear can easily cause structural vibrations, operational instability, and decreased control accuracy, and may even lead to satellite failure. Therefore, developing a stable and long-lasting reaction wheel has become a pressing challenge. [Summary of the Invention]

[0003] The present invention provides an electromagnetic reaction wheel, which operates stably and has a long service life.

[0004] An electromagnetic reaction wheel of the present invention includes an annular tube, a plurality of coil assemblies, a magnetic assembly, and a control unit. The annular tube has a cavity. Each coil assembly includes a plurality of first coils and a plurality of second coils. The first coils are disposed on an outer surface of the annular tube. The second coils are located away from the annular tube. The first and second coils are arranged in a Hellbeck array. The magnetic assembly is movably disposed within the cavity of the annular tube. The control unit is electrically connected to the coil assemblies. The control unit is adapted to control the energization or de-energization of the first and / or second coils to drive the magnetic assembly to move relative to the annular tube within the cavity.

[0005] In one embodiment of the present invention, the aforementioned second coils are disposed between the center of the annular tube and the annular tube.

[0006] In one embodiment of the present invention, the first coils described above include two first coils, and the second coils are located between the two first coils.

[0007] In one embodiment of the present invention, the first coils and the second coils described above are arranged along a virtual arc.

[0008] In one embodiment of the present invention, the electromagnetic reaction wheel further includes a core. The core is made of a soft magnetic material and is disposed within these second coils.

[0009] In one embodiment of the present invention, the electromagnetic reaction wheel further includes a plurality of cores. These cores are made of soft magnetic material and are respectively inserted into these second coils.

[0010] In one embodiment of the present invention, the magnetic component described above includes two magnetic pole groups. Each magnetic pole group includes a first magnetic pole and a second magnetic pole with opposite polarities. The first magnetic pole and the second magnetic pole are arranged along a first direction. The first magnetic poles of each magnetic pole group are far apart from each other, and the second magnetic poles of each magnetic pole group are adjacent to each other.

[0011] In one embodiment of the present invention, the magnetic component described above includes two magnet groups. Each magnet group includes a plurality of magnets. These magnets are arranged in a Hellbeck array. A strong side of each magnet group is away from each other, and a weak side of each magnet group is adjacent to each other.

[0012] In one embodiment of the present invention, the above-described second coils include at least three second coils.

[0013] In one embodiment of the present invention, the above-described coil assemblies include at least three coil assemblies.

[0014] Based on the above, the electromagnetic reaction wheel of the present invention includes an annular tube, multiple coil assemblies, a magnetic assembly, and a control unit. The first and second coils in each coil assembly are arranged in a Heilbeck array, generating a magnetic field along the circumference of the annular tube. By appropriately controlling the energization or de-energization of the first and / or second coils through the control unit, the magnetic assembly can be driven to move smoothly relative to the annular tube within the cavity, thereby generating appropriate angular momentum and effectively adjusting the attitude of a spacecraft, such as a satellite. Since the electromagnetic reaction wheel does not require flywheels or bearings, it avoids the problem of bearing wear, thus having a longer service life and contributing to increased operational stability.

Implementation Method

[0015] FIG1 is a schematic diagram of an electromagnetic reaction wheel according to an embodiment of the present invention. FIG2 is another schematic diagram of the electromagnetic reaction wheel of FIG1. ​​It should be noted that the cavity 111 and the magnetic component 130 in FIG2 are drawn with dashed lines.

[0016] Referring to Figures 1 and 2, in this embodiment, the electromagnetic reaction wheel 100 can be installed inside a spacecraft, such as a CubeSat (with a unit size of 10 cm * 10 cm * 10 cm and a unit weight of approximately 1.33 kg), and can generate appropriate angular momentum, thereby effectively adjusting the attitude of the spacecraft in space. Specifically, the electromagnetic reaction wheel 100 includes an annular tube 110, multiple coil assemblies 120, a magnetic assembly 130 (Figure 2), and a control unit 140.

[0017] The annular tube 110 has a cavity 111 (Figure 2), which is disposed around the annular tube 110. The material of the annular tube 110 is, for example, PFA (perfluoroalkyl vinyl ether copolymer), which has good weather resistance and chemical stability. The annular tube 110 needs to be suitable for extreme environments such as space environments, but its material is not limited thereto.

[0018] The plurality of coil assemblies 120 includes at least three coil assemblies 120 such that the magnetic field generated by the coil assemblies 120 completely covers the annular tube 110. As shown in FIG2, the plurality of coil assemblies 120 in this embodiment includes three coil assemblies 120a, 120b, and 120c. The angle θ of each coil assembly 120a, 120b, and 120c is defined as the central angle of the annular tube 110 corresponding to the distribution range of the coil assembly. In this embodiment, the angle θ of each coil assembly 120a, 120b, and 120c is equal to or approximately 120 degrees.

[0019] In another embodiment, the plurality of coil assemblies 120 includes four coil assemblies 120, each coil assembly 120 having an angle θ equal to or approximately 90 degrees. It should be noted that the more coil assemblies 120 there are, the stronger the magnetic field, but the overall weight will also increase; preferably, the number of coil assemblies 120 is three.

[0020] Each coil assembly 120a, 120b, and 120c includes a plurality of first coils 121 and a plurality of second coils 122. Taking coil assembly 120a as an example, the first coil 121 of coil assembly 120a is disposed on an outer surface 112 of the annular tube 110, and the second coils 122 are located away from the annular tube 110. More specifically, the first coil 121 includes two first coils 121, which are arranged at intervals, and the angle θ corresponding to the two first coils 121 does not exceed 120 degrees.

[0021] The second coil 122 includes at least three second coils 122 to form a sufficient magnetic field strength and magnetic field gradient. In this embodiment, the second coil 122 includes three second coils 122, but the number of second coils 122 is not limited thereto. These second coils 122 are located between the two first coils 121 and are disposed between the center C of the annular tube 110 and the outer surface 112 of the annular tube 110. That is, the second coils 122 are disposed close to the inner side of the annular tube 110.

[0022] In this embodiment, the material of the first coil 121 and the material of the second coil 122 are copper or aluminum alloy, which have good conductivity, but the material of the first coil 121 and the material of the second coil 122 are not limited thereto.

[0023] The magnetic field effect formed by the first coil 121 and the second coil 122 will be explained below using coil assembly 120a as an example. Figure 3 is a partially enlarged schematic diagram of the electromagnetic reaction wheel in Figure 1. It should be noted that the cavity 111 and the magnetic assembly 130 in Figure 3 are drawn with dashed lines.

[0024] Please refer to Figure 3. In this embodiment, the first coil 121 and the second coil 122 are arranged along a virtual arc CV and are arranged to form a Halbach array with an arc, which is equivalent to a part of a Halbach quadrupole.

[0025] As shown in Figure 3, the first coil 121 and the second coil 122 are electromagnets, which can generate a magnetic field with a magnetic field direction F after being energized. Specifically, in this embodiment, the magnetic field direction F of the first coil 121 and the magnetic field direction F of the second coil 122 are counterclockwise. In another embodiment, the magnetic field direction F of the first coil 121 and the magnetic field direction F of the second coil 122 are clockwise.

[0026] In this embodiment, the magnetic component 130 is movably disposed within the cavity 111 of the annular tube 110. When the first coil 121 and the second coil 122 are arranged in the Heilbeck array as described above, a magnetic field direction G can be formed along a first direction D1 (i.e., the circumferential direction of the annular tube 110) of the annular tube 110. Under the action of the magnetic field, the magnetic component 130 located between the two first coils 121 (e.g., the first coils 121 at positions P1 and P2) moves relative to the annular tube 110 in the cavity 111 along the magnetic field direction G, thereby generating angular momentum. This causes the satellite to move in the opposite direction due to the reaction force, thereby effectively adjusting the satellite's attitude in space.

[0027] It is worth noting that if the electromagnetic reaction wheel 100 does not include the second coil 122 (i.e., only the first coil 121), the magnetic component 130 can still be moved by the magnetic field of the first coil 121. However, in this design, if the magnetic component 130 previously stopped between the first coils 121 at positions P1 and P2, especially at the middle position equidistant from the two first coils 121 (e.g., the position where the magnetic component 130 is located in Figure 3), since this position is least affected by the magnetic field of the first coil 121, the magnetic component 130 is difficult to be driven by the first coil 121 after it is energized, or the current of the first coil 121 needs to be increased to make the magnetic component 130 start to move.

[0028] In contrast, this design uses a second coil 122 in combination with a first coil 121 to form a Heilbeck array, which improves the overall magnetic field strength and magnetic field gradient. Even if the magnetic component 130 was previously in the middle position between the two first coils 121, it can still be easily driven to start moving under the effect of the enhanced magnetic field.

[0029] Furthermore, compared to designs without a Hellbeck array, the electromagnetic reaction wheel 100 of this embodiment can generate a stronger magnetic field under the same current and total number of coil turns, making the movement of the magnetic component 130 in the cavity 111 more powerful. In addition, this design does not require increasing the total number of coil turns to increase the magnetic field strength, thus saving manufacturing and operating costs and not increasing the overall weight, which is beneficial for applying the electromagnetic reaction wheel 100 to small satellites such as CubeSats.

[0030] In this embodiment, the magnetic field formed by the second coil 122 helps to make the magnetic field direction G at the annular tube 110 close to the first direction D1 of the annular tube 110. In this way, it can be ensured that the magnetic component 130 moves smoothly between the two first coils 121 in the same coil assembly (e.g., coil assembly 120a). That is to say, the arrangement of the second coil 122 has a better effect of guiding the magnetic component 130.

[0031] In addition, compared with the usual Heilbeck array composed of permanent magnets, the Heilbeck array in this embodiment is composed of electromagnets (i.e., the first coil 121 and the second coil 122), and the magnitude and direction of the magnetic field generated by the Heilbeck array can be adjusted by changing the current, so as to achieve the effect of flexibly adjusting the magnetic field.

[0032] In addition, as mentioned above, the Heilbeck array in this embodiment is equivalent to a part of the Heilbeck quadrupole.

[0033] The specific operation of the electromagnetic reaction wheel 100 will be explained next. Figure 4 is a partially enlarged schematic diagram of the electromagnetic reaction wheel 100 in Figure 3. It should be noted that the second coil 122 in Figure 4 is hidden in order to clearly show the relationship between the first coil 121 and the magnetic component 130.

[0034] Referring simultaneously to Figures 3 and 4, in this embodiment, the control unit 140 is electrically connected to each coil assembly 120a, 120b, 120c, and is adapted to control the first coil 121 and / or the second coil 122 to be energized or de-energized, so as to drive the magnetic assembly 130 to move relative to the annular tube 110 in the cavity 111. Figure 3 schematically illustrates the control unit 140 connected to the first coil 121 at position P4, but it should be understood that the control unit 140 is electrically connected to each first coil 121 and each second coil 122.

[0035] In this embodiment, the control unit 140 may be a microprocessor or microcontroller such as STM32, but the type of control unit 140 is not limited thereto.

[0036] In this embodiment, the magnetic component 130 includes a housing 131 (FIG. 4) and two magnetic pole groups 132 and 133 (FIG. 4). The two magnetic pole groups 132 and 133 are disposed in the housing 131, and each magnetic pole group 132 and 133 includes a first magnetic pole Q1 and a second magnetic pole Q2 with opposite polarities. The first magnetic pole Q1 is, for example, an N pole, and the second magnetic pole Q2 is, for example, an S pole. The first magnetic pole Q1 and the second magnetic pole Q2 are arranged along a first direction D1. The first magnetic poles Q1 of each magnetic pole group 132 and 133 are far apart from each other, and the second magnetic poles Q2 of each magnetic pole group 132 and 133 are adjacent to each other.

[0037] When the magnetic component 130 is located between two first coils 121 (e.g., the first coils 121 at positions P1 and P2) of the same coil assembly (e.g., coil assembly 120a), the control unit 140 can control the first coil 121 and the second coil 122 to be energized. At this time, since the magnetic field direction F of the first coils 121 at positions P1 and P2 is counterclockwise, the first magnetic pole Q1 of the magnetic pole group 132 repels the first coil 121 at position P1, and the first magnetic pole Q1 of the magnetic pole group 133 attracts the first coil 121 at position P2. Thus, the magnetic component 130 moves along the magnetic field direction G (i.e., counterclockwise) under the action of the magnetic field.

[0038] As shown in Figure 3, when the magnetic component 130 approaches the first coil 121 at position P2, the control unit 140 can control the first coil 121 at position P2 to be de-energized so that the magnetic component 130 can pass smoothly through the first coil 121 at that location and avoid being attracted by the first coil 121 and stopping.

[0039] When the magnetic component 130 passes through the first coil 121 at position P2 and is located between the first coils 121 at positions P2 and P4 (i.e., the two adjacent first coils 121 in adjacent coil assemblies 120a and 120b), the first coil 121 at position P2 can be energized so that the magnetic component 130 is subjected to a repulsive force and can move more towards the first coil 121 at position P4. In another embodiment, when the magnetic component 130 is located between the first coils 121 at positions P2 and P4, the first coil 121 at position P2 is not energized, and the magnetic component 130 moves towards the first coil 121 at position P4 by the magnetic force applied by the previous coil assembly 120a.

[0040] Similarly, in this embodiment, when the magnetic component 130 is located between the first coil 121 at position P3 and position P1, before passing the first coil 121 at position P1, the first coil 121 at position P3 can be energized so that the magnetic component 130 is subjected to a repulsive force and can move more towards the first coil 121 at position P1. In another embodiment, when the magnetic component 130 is located between the first coil 121 at position P3 and position P1, the first coil 121 at position P3 is not energized, and the magnetic component 130 moves towards the first coil 121 at position P1 by the magnetic force applied by the previous coil component 120c.

[0041] Furthermore, after the magnetic component 130 passes the first coil 121 at position P2, the previously energized second coil 122 can be de-energized to save power.

[0042] In this embodiment, when the magnetic component 130 passes through the first coil 121 at position P4 and is located between the two first coils 121 of the coil component 120b, the control unit 140 can control the first coil 121 and the second coil 122 of the coil component 120b to generate a magnetic field as described above for controlling the coil component 120a to drive the magnetic component 130 to continue moving.

[0043] Similarly, when the magnetic component 130 is located between the two first coils 121 of the coil assembly 120c, the control unit 140 can control the first coil 121 and the second coil 122 of the coil assembly 120c to be energized to achieve the aforementioned magnetic field effect. Furthermore, in this embodiment, when one group of coil assemblies (e.g., coil assembly 120a) is turned on, the other two coil assemblies 120 (e.g., coil assemblies 120b, 120c) can remain de-energized except for the specific first coil 121, thereby saving power.

[0044] In addition, in this embodiment, the first coil 121 and the second coil 122 of each coil assembly 120a, 120b, 120c can be applied with the same or different currents as needed to generate a suitable magnetic field to drive the magnetic assembly 130 to move.

[0045] If the magnetic component 130 is to move in the opposite direction to the first direction D1, it is only necessary to apply a reverse current to each coil, which will generate a magnetic field direction opposite to the magnetic field direction G shown in Figure 4, so that the magnetic component 130 moves in the direction of the magnetic field (i.e., clockwise).

[0046] To stop the magnetic component 130 from moving, the control unit 140 can de-energize all the coils (i.e., the first coil 121 and the second coil 122) in the electromagnetic reaction wheel 100. In this way, the magnetic component 130 will gradually stop due to the depletion of kinetic energy in the absence of a magnetic field. Alternatively, the control unit 140 can allow only the first coil 121 to be energized and keep the other coils de-energized, so that the moving magnetic component 130 is immediately attracted to the first coil 121 and stops.

[0047] In addition, in this embodiment, the number of magnetic components 130 is one. In another embodiment, the number of magnetic components 130 is two, which can provide higher angular momentum. Of course, the number of magnetic components 130 is not limited thereto. In yet another embodiment, the magnetic component 130 is, for example, a steel ball made of soft magnetic material.

[0048] As can be seen from the above description, this design uses electromagnets to form a Heilbeck array to create a specific magnetic field direction G on the annular tube 110, thereby driving the magnetic component 130 to move in the cavity 111 of the annular tube 110, generating sufficient angular momentum so that the satellite moves in the opposite direction due to the reaction force, thereby achieving the effect of effectively adjusting the satellite attitude in space.

[0049] It is worth mentioning that the electromagnetic reaction wheel 100 of this embodiment does not have a flywheel and bearing structure, so it can avoid the structural vibration, unstable operation and reduced control accuracy that often occur in conventional reaction wheels due to bearing wear, and has a longer service life and excellent operational stability.

[0050] Furthermore, in this embodiment, the magnetic component 130 of the electromagnetic reaction wheel 100 moves only on a single plane (i.e., the plane of the paper) where the annular tube 110 is located. In order to enable the satellite's three-axis attitude to be adjusted, three electromagnetic reaction wheels 100 need to be configured in the satellite, and the planes where each electromagnetic reaction wheel 100 is located are orthogonal to each other.

[0051] FIG5 is a schematic diagram of a magnetic component according to another embodiment of the present invention. The embodiment shown in FIG5 differs from the embodiment shown in FIG4 in that the magnetic component 130a in FIG5 adopts a different design.

[0052] In detail, the magnetic component 130a includes a housing 131 and two magnet groups 134 and 135. The two magnet groups 134 and 135 are disposed in the housing 131 and each includes a plurality of magnets M. The magnets M of each magnet group 134 and 135 are arranged to form a linear Hellbeck array. The linear Hellbeck array has a strong side S1 and a weak side S2, and the magnetic field strength of the strong side S1 is much greater than the magnetic field strength of the weak side S2.

[0053] Taking the magnet group 134 in Figure 5 as an example, the magnetic field directions H of the magnets M from top to bottom are, for example, down, left, up, right, down, left, up. A strong side S1 can be formed on the left side of the magnet group 134, and a weak side S2 can be formed on the right side of the magnet group 134.

[0054] On the other hand, regarding the magnet group 135, the magnetic field directions H of the magnets M from top to bottom are, for example, down, right, up, left, down, right, up. A strong side S1 can be formed on the right side of the magnet group 135, and a weak side S2 can be formed on the left side of the magnet group 135. That is, the strong sides S1 of each magnet group 134 and 135 are far away from each other, and the weak sides S2 of each magnet group 134 and 135 are close to each other.

[0055] As in the embodiment of FIG4 above, when the magnetic component 130a of this embodiment is located between the two first coils 121 (FIG. 4) of the same coil assembly (e.g., coil assembly 120a in FIG. 4), the strong side S1 of the magnet group 134 repels the adjacent first coil 121, and the strong side S1 of the magnet group 135 attracts the adjacent first coil 121. Thus, the magnetic component 130a moves along the magnetic field direction G under the action of the magnetic field to generate appropriate angular momentum, achieving the effect of adjusting the satellite's attitude in space.

[0056] In addition, in this embodiment, the number of magnets M in each magnet group 134 and 135 is shown as seven, but the number of magnets M is not limited to this, as long as it is sufficient to form a linear Heilbeck array.

[0057] FIG6 is a partially enlarged schematic diagram of an electromagnetic reaction wheel according to another embodiment of the present invention. The embodiment shown in FIG6 differs from the embodiment shown in FIG4 in that the electromagnetic reaction wheel 100b in FIG6 further includes a core 150.

[0058] In detail, the core 150 of this embodiment is disposed in all the second coils 122 of the same coil assembly (e.g., coil assembly 120a), thereby allowing the core 150 to be magnetized to further strengthen the magnetic field. The magnetic flux density at the middle position between the two first coils 121 (where the magnetic component 130 is located in FIG6) can be increased to 328.6% for example.

[0059] Furthermore, the core 150 is a soft magnetic material, preferably ferrite or steel lamination. When copper and ferrite are used as the materials for the coil and core 150 respectively, the addition of the core 150 can reduce the average mass density of the electromagnetic reaction wheel 100b by, for example, up to 28.6%, since the average mass density of ferrite is lower than that of copper. In other words, the electromagnetic reaction wheel 100b of this embodiment not only reduces the average mass density but also increases the magnetic field strength and magnetic field gradient, exhibiting excellent magnetic field performance. The remaining configurations and components of the electromagnetic reaction wheel 100b are the same as or similar to those of the aforementioned electromagnetic reaction wheel 100, and will not be described again here.

[0060] FIG7 is a partially enlarged schematic diagram of an electromagnetic reaction wheel according to another embodiment of the present invention. The embodiment shown in FIG7 differs from the embodiment shown in FIG6 in that the electromagnetic reaction wheel 100c in FIG7 further includes a plurality of cores 150a, 150b, and 150c.

[0061] In detail, multiple cores 150a, 150b, and 150c are respectively threaded through multiple second coils 122 of the same coil assembly (e.g., coil assembly 120a), thereby magnetizing the cores 150a, 150b, and 150c to further strengthen the magnetic field. In this embodiment, three cores are shown, but the number of cores is not limited thereto, as long as it corresponds to the number of second coils 122. The remaining configuration and components of the electromagnetic reaction wheel 100c are the same as or similar to those of the aforementioned electromagnetic reaction wheels 100 and 100b, and will not be described again here.

[0062] In summary, the electromagnetic reaction wheel of the present invention includes an annular tube, multiple coil assemblies, a magnetic assembly, and a control unit. The first and second coils in each coil assembly are arranged in a Heilbeck array, generating a magnetic field along the circumference of the annular tube. By appropriately controlling the energization or de-energization of the first and / or second coils through the control unit, the magnetic assembly can be driven to move smoothly relative to the annular tube within its cavity, thereby generating appropriate angular momentum and effectively adjusting the attitude of spacecraft such as satellites. Since the electromagnetic reaction wheel does not require flywheels or bearings, it avoids the problem of bearing wear, thus having a longer service life and contributing to increased operational stability.

[0063] Furthermore, by forming a Hellbeck array using the first and second coils, the magnetic field strength and magnetic field gradient of the electromagnetic reaction wheel can be enhanced without increasing the current or the total number of coil turns. This allows magnetic components located at any position in any annular tube to be started and move smoothly at any time, saving manufacturing and operating costs without increasing the overall weight. Simultaneously, since this Hellbeck array is composed of electromagnets, the magnitude and direction of the magnetic field can be adjusted by changing the current, achieving a flexible adjustment of the magnetic field.

[0064] In addition, the electromagnetic reaction wheel of the present invention may further include a core body, which is inserted into the second coil, thereby further strengthening the magnetic field and reducing the average mass density of the electromagnetic reaction wheel, thereby achieving excellent magnetic field performance. [Simplified Explanation of the Diagram]

[0065] FIG1 is a schematic diagram of an electromagnetic reaction wheel according to an embodiment of the present invention. FIG2 is another schematic diagram of the electromagnetic reaction wheel of FIG1. ​​FIG3 is a partially enlarged schematic diagram of the electromagnetic reaction wheel of FIG1. ​​FIG4 is a partially enlarged schematic diagram of the electromagnetic reaction wheel of FIG3. FIG5 is a schematic diagram of a magnetic component according to another embodiment of the present invention. FIG6 is a partially enlarged schematic diagram of an electromagnetic reaction wheel according to another embodiment of the present invention. FIG7 is a partially enlarged schematic diagram of an electromagnetic reaction wheel according to yet another embodiment of the present invention.

Claims

1. An electromagnetic reaction wheel, comprising: A ring-shaped tube having a cavity; Multiple coil assemblies, each coil assembly including: multiple first coils disposed on an outer surface of the annular tube; The first and second coils are located away from the annular tube, wherein the first and second coils are arranged in a Halbach array; a magnetic component is movably disposed within the cavity of the annular tube; and a control unit is electrically connected to the coil assembly, wherein the control unit is adapted to control the first and / or second coils to be energized or de-energized to drive the magnetic component to move relative to the annular tube within the cavity.

2. The electromagnetic reaction wheel as claimed in claim 1, wherein the second coils are disposed between the center of the annular tube and the annular tube.

3. The electromagnetic reaction wheel as claimed in claim 1, wherein the first coils comprise two first coils and the second coils are located between the two first coils.

4. The electromagnetic reaction wheel as claimed in claim 1, wherein the first coils and the second coils are arranged along a virtual arc.

5. The electromagnetic reaction wheel as claimed in claim 1 further includes a core, wherein the core is a soft magnetic material and is disposed within the second coils.

6. The electromagnetic reaction wheel as claimed in claim 1 further includes a plurality of cores, wherein the cores are made of soft magnetic material and are respectively disposed in the second coils.

7. The electromagnetic reaction wheel as claimed in claim 1, wherein the magnetic component includes two magnetic pole groups, each magnetic pole group including a first magnetic pole and a second magnetic pole of opposite polarity, the first magnetic pole and the second magnetic pole being arranged along a first direction, the first magnetic poles of each magnetic pole group being far apart from each other, and the second magnetic poles of each magnetic pole group being adjacent to each other.

8. The electromagnetic reaction wheel as claimed in claim 1, wherein the magnetic component comprises two magnet groups, each magnet group comprising a plurality of magnets arranged in a Halbach array, wherein a strong side of each magnet group is far from each other and a weak side of each magnet group is adjacent to each other.

9. The electromagnetic reaction wheel as claimed in claim 1, wherein the second coils comprise at least three second coils.

10. The electromagnetic reaction wheel as claimed in claim 1, wherein the coil assemblies comprise at least three coil assemblies.

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