Multi-degree of freedom electromagnetic machine with halbach array

Abstract

This invention discloses a multi-degree-of-freedom electromagnetic machine, comprising a spherical structure, a first coil, a second coil, a non-magnetic structure, and a Helbeck array. The spherical structure has a first axis of symmetry, a second axis of symmetry, and a third axis of symmetry, which are perpendicular to each other. The first coil is wound around the spherical structure around the first axis of symmetry, and the second coil is wound around the spherical structure around the second axis of symmetry. The non-magnetic structure is spaced apart from the spherical structure and at least partially surrounds it. The Helbeck array is mounted on the non-magnetic structure and includes N magnets, where N is a multiple of 4. The mounting of the spherical structure and the non-magnetic structure allows relative rotation between the non-magnetic structure and the spherical structure.

Description

Technical Field

[0001] This invention relates generally to electromagnetic machines, and more specifically to multi-degree-of-freedom electromagnetic machines having a Halbach array. Background Technology

[0002] With the development of UAVs (Unmanned Aerial Vehicles), aerial drones, robotics, office automation, and intelligent flexible manufacturing assembly systems, the development of multi-degree-of-freedom (DOF) precision actuation systems has become essential. Conventionally, applications relying on multi-degree-of-freedom motion are typically accomplished by using separate motors / actuators for each axis, resulting in complex transmission systems and relatively heavy structures.

[0003] With the advent of spherical motors, there have been numerous attempts to replace complex multi-degree-of-freedom components with a single spherical motor assembly. A typical spherical motor consists of a central sphere around which coils that can be placed orthogonally to each other are wound. This sphere is surrounded by multipole magnets, which can be in the form of spheres or open cylinders.

[0004] Unfortunately, many existing spherical motors exhibit some suboptimal characteristics. For example, many existing spherical motors exhibit non-uniform torque at different positions, making their control relatively complex. This is at least partly due to the non-sinusoidal air gap flux. Additionally, the rotating components (e.g., armature / rotor) are relatively heavy due to the arrangement of magnets and steel. Furthermore, many existing spherical motors are relatively difficult to control due to their non-linear torque distribution and do not provide the maximum expected torque at all positions, thus limiting useful work and average torque output.

[0005] Therefore, there is a need for a multi-degree-of-freedom electromagnetic machine that exhibits more uniform torque at different locations and / or sinusoidal air-gap flux and / or is relatively easier to control. This invention at least satisfies these needs. Summary of the Invention

[0006] This summary is provided to describe selected concepts in a simplified form, which are further described in the detailed embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0007] In one embodiment, the multi-degree-of-freedom electromagnetic machine includes a spherical structure, a first coil, a second coil, a third coil, a non-magnetic structure, and a Helbeck array. The spherical structure has a first axis of symmetry, a second axis of symmetry, and a third axis of symmetry, which are perpendicular to each other. The first coil is wound around the spherical structure about the first axis of symmetry, and the second coil is wound around the spherical structure about the second axis of symmetry. The non-magnetic structure is spaced apart from the spherical structure and at least partially surrounds it. The Helbeck array is mounted on the non-magnetic structure and includes N magnets, where N is a multiple of 4. The mounting of the spherical structure and the non-magnetic structure allows relative rotation between the non-magnetic structure and the spherical structure.

[0008] In another embodiment, the multi-degree-of-freedom electromagnetic machine includes a spherical structure, a first coil, a second coil, an aluminum structure, and a 16-magnet Hellbeck array. The spherical structure has a first axis of symmetry, a second axis of symmetry, and a third axis of symmetry, which are perpendicular to each other. The first coil is wound around the spherical structure about the first axis of symmetry, and the second coil is wound around the spherical structure about the second axis of symmetry. The aluminum structure is spaced apart from the spherical structure and at least partially surrounds it. The aluminum structure is mounted to rotate relative to the spherical structure and has an inner surface and an outer surface. The 16-magnet Hellbeck array is mounted on the inner surface of the aluminum structure.

[0009] In another embodiment, the multi-degree-of-freedom electromagnetic machine includes a spherical structure, a first coil, a second coil, a third coil, an aluminum structure, and a 16-magnet Hellbeck array. The spherical structure comprises a magnetically permeable material and has a first axis of symmetry, a second axis of symmetry, and a third axis of symmetry, wherein the first, second, and third axes of symmetry are arranged perpendicular to each other. The first coil is wound around the spherical structure about the first axis of symmetry, the second coil is wound around the spherical structure about the second axis of symmetry, and the third coil is wound around the spherical structure about the third axis of symmetry. The aluminum structure is spaced apart from and at least partially surrounds the spherical structure and has an inner surface and an outer surface. The 16-magnet Hellbeck array is mounted on the inner surface of the aluminum structure. The mounting of the spherical structure and the aluminum structure allows relative rotation between the non-magnetic structure and the spherical structure.

[0010] Furthermore, other desired features and characteristics of the multi-degree-of-freedom electromagnetic machine will become apparent from the following detailed description and the appended claims, taking into account the accompanying drawings and the foregoing background art. Attached Figure Description

[0011] The invention will now be described with reference to the following figures, wherein similar numbers denote similar elements, and wherein:

[0012] Figure 1 This is a plan view of one implementation scheme of a multi-degree-of-freedom electromagnetic machine;

[0013] Figure 2 yes Figure 1 A cross-sectional view of the multi-degree-of-freedom electromagnetic machine shown;

[0014] Figure 3 It can be used to implement Figure 1 and Figure 2 The illustration shows the spherical structure and stator windings of the multi-degree-of-freedom electromagnetic machine.

[0015] Figure 4 It can be used to implement Figure 1 and Figure 2 A plan view of one embodiment of the rotor and Heilbeck array of the multi-degree-of-freedom electromagnetic machine shown;

[0016] Figure 5 It can be used to implement Figure 1 and Figure 2 A top view of one embodiment of the rotor and Heilbeck array of the multi-degree-of-freedom electromagnetic machine shown;

[0017] Figure 6 It can be used to implement Figure 1 and Figure 2 A top view of another embodiment of the rotor and Heilbeck array of the multi-degree-of-freedom electromagnetic machine shown;

[0018] Figure 7 This is a plan view of another implementation scheme of a multi-degree-of-freedom electromagnetic machine;

[0019] Figure 8 yes Figure 7 A cross-sectional view of the multi-degree-of-freedom electromagnetic machine shown;

[0020] Figure 9 It shows Figure 1 and Figure 2 The diagram shows the relationship between air gap magnetic flux and position in the multi-degree-of-freedom electromagnetic machine shown.

[0021] Figure 10 This diagram illustrates the relationship between air gap flux and position for currently known multi-degree-of-freedom electromagnetic machines; and

[0022] Figure 11 It shows Figure 1 and Figure 2 The diagram shows the relationship between torque and position for the multi-degree-of-freedom electromagnetic machine and other known multi-degree-of-freedom electromagnetic machines. Detailed Implementation

[0023] The following detailed descriptions are merely exemplary in nature and are not intended to limit the invention or its application and use. As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Therefore, any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All embodiments described herein are exemplary embodiments provided to enable those skilled in the art to make or use the invention, and do not limit the scope of the invention as defined by the claims. Furthermore, it is not intended to be bound by any express or implied theory presented in the foregoing technical field, background art, summary of the invention, or the following detailed descriptions.

[0024] See Figure 1 and Figure 2 Plan view and cross-sectional view of one embodiment of a multi-degree-of-freedom electromagnetic machine 100 are shown. The electromagnetic machine 100 shown includes a spherical structure 102, a plurality of coils 104, a non-magnetic structure 106, and a Heilbeck array 108. At least in the illustrated embodiment, the spherical structure 102 is hollow. That is, as in Figure 2 As shown more clearly, the spherical structure includes an inner surface 101 and an outer surface 103, with the inner surface 101 defining a cavity 105. The spherical structure 102 is preferably made of a magnetically permeable material, but it may also be made of a non-magnetic material if desired or necessary. While any of many magnetically permeable materials can be used, some non-limiting examples include steel, such as DT4, DT4A, DT4E, DT4C, and Hiperco. and Hiperco Or low-carbon steel.

[0025] Regardless of the specific materials, and as Figure 3 As shown more clearly, the spherical structure 102 has three vertically arranged axes of symmetry: a first axis of symmetry 110-1, a second axis of symmetry 110-2, and a third axis of symmetry 110-3 (only in...). Figure 3 (As shown in the diagram). The spherical structure 102 has a plurality of coils 104 wound thereon. In the illustrated embodiment, these coils include a first coil 104-1, a second coil 104-2, and a third coil 104-3. However, it should be understood that in some embodiments, the electromagnetic machine 100 may be implemented with only two coils instead of three, and operate in the form of a finite angular torque motor with two degrees of freedom.

[0026] like Figure 3Further shown, a first coil 104-1 is wound around a first axis of symmetry 110-1 on a spherical structure 102, a second coil 104-2 is wound around a second axis of symmetry 110-2 on a spherical structure 102, and a third coil 104-3, when included, is wound around a third axis of symmetry 110-3 on a spherical structure 102. It should be noted that a sphere has an infinite number of axes of symmetry. Therefore, the first axis of symmetry 110-1, the second axis of symmetry 110-2, and the third axis of symmetry 110-3 can be any one of these axes of symmetry, as long as all three axes of symmetry are perpendicular to each other.

[0027] Now return to Figure 1 and Figure 2 As can be seen, the non-magnetic structure 106 is spaced apart from and at least partially surrounds the spherical structure 102. As the name suggests, the non-magnetic structure 106 is made of a non-magnetic material. While any of a variety of plastics or non-magnetic metals may be used, in a particular embodiment, the non-magnetic structure 106 is made of aluminum. Therefore, in some cases, it may also be referred to as an aluminum rotor 106. The non-magnetic structure 106 is also mounted to rotate relative to the spherical structure 102. More specifically, it is mounted to rotate relative to the spherical structure 102 about a first axis of symmetry 110-1 and a second axis of symmetry 110-2. A particular mounting configuration that allows these rotations will be described subsequently.

[0028] See now Figure 4 and Figure 5 An embodiment of a nonmagnetic structure 106 separate from the electromagnetic machine 100 is shown. As clearly shown therein, the nonmagnetic structure 106 includes a body 402, a first shaft portion 404, and a second shaft portion 406. The body 402 has an inner surface 408 and an outer surface 412. The first shaft portion 404 and the second shaft portion 406 are diametrically opposed to each other and each extends radially outward from the body 402. As will be described in more detail below, both the first shaft portion 404 and the second shaft portion 406 are rotatably mounted.

[0029] Continue to refer to Figure 4 It can be seen that the Hellbeck array 108 is mounted on the non-magnetic structure 106. Figure 1 , Figure 2 , Figure 4 and Figure 5 In the embodiment shown, the Hellbeck array 108 is mounted on the inner surface 408. However, this is merely an example of one embodiment. In other embodiments, such as... Figure 6As shown, the Hellbeck array 108 can be mounted on the outer surface 412. Regardless of which surface it is mounted on, the Hellbeck array 108 is embodied as a Hellbeck array 108 with N magnets, where N is a multiple of 4. In a particular preferred embodiment, the Hellbeck array 108 is embodied as a 16-magnet Hellbeck array 108 (e.g., N equals 16). It is well known that a Hellbeck array is a magnetic configuration that maximizes the magnetic field on one side and minimizes the magnetic field on the other. When the Hellbeck array is configured as a ring, as in the illustrated embodiment, the magnetic field lines are concentrated towards the spherical structure 102 inside the ring.

[0030] Now return to Figure 1 and Figure 2 As can be seen, the electromagnetic machine 100 further includes a frame 112 rotatably connected to the spherical structure 102 and the nonmagnetic structure 106. Specifically, the frame 112 is connected to the spherical structure 102 and the nonmagnetic structure 104 such that the nonmagnetic structure 106 and the frame 112 can rotate together relative to the spherical structure 102 about a first axis of symmetry 110-1, and the nonmagnetic structure 106 can rotate relative to the frame 112 and the spherical structure 102 about a second axis of symmetry 110-1. Although the frame 112 can be constructed and implemented differently, in the illustrated embodiment, it includes a mounting flange 114, a fixed shaft 116, a lower yoke 118, and an upper yoke 122.

[0031] Mounting flange 114 is used to mount frame 112 and the entire electromagnetic machine 100 to a structure not shown. Although mounting flange 114 can be designed in various shapes and made of various types of materials, in the embodiment shown it is slightly cylindrical in shape and made of aluminum.

[0032] The fixed shaft 116 includes a first end 124 and a second end 126 and extends through the spherical structure 102. As the name suggests, the fixed shaft 116 is fixedly coupled to the spherical structure 102 and is also fixedly coupled to the mounting flange 114 at its first end 124 and does not rotate. Although the fixed shaft 116 can be made of various types of materials, in the illustrated embodiment it is made of aluminum.

[0033] The lower yoke 118 is connected to the upper yoke 122 via suitable connecting hardware. This connecting hardware 126 can vary, but in the illustrated embodiment includes multiple fasteners 126, a cover 128, and a cover plate 132. The lower yoke 118 is also rotatably connected to the fixed shaft 116 via a first bearing assembly 134 mounted on the fixed shaft 116. Thus, the lower yoke 118 can rotate relative to the fixed shaft 116 and the mounting flange 114 about a first axis of symmetry. The upper yoke 122 is rotatably connected to the fixed shaft 116 via a second bearing assembly 136 also mounted on the fixed shaft 116. Thus, the upper yoke 122 can rotate together with the lower yoke 118 about a first axis of symmetry 110-1.

[0034] like Figure 1 It is also shown that a third bearing assembly 138 is mounted on the first shaft portion 404, and a fourth bearing assembly 142 is mounted on the second rotor portion 406. The third bearing assembly 138 and the fourth bearing assembly 142 are further connected to the lower yoke 118 and the upper yoke 122, respectively. Therefore, as described above, the non-magnetic structure 106 can rotate relative to the frame 112 and the spherical structure 102 about the first axis of symmetry 110-1.

[0035] In the above configuration, the stator winding 104 is selectively energized to generate a Lorentz force between the stator winding 104 and the 16-magnet Hellbeck array 108. This correspondingly imparts torque to the non-magnetic structure 106, causing it to rotate relative to the stator 102 about one or both of the first rotation axis 110-1 and the second rotation axis 110-2.

[0036] In the above embodiment, the non-magnetic structure 106 is mounted to rotate relative to the spherical structure 102. In another embodiment, the spherical structure 102 is mounted to rotate relative to the non-magnetic structure 106. An example of this embodiment is shown in... Figure 7 and Figure 8 As shown, a non-magnetic structure 106 is fixedly mounted to a frame 702, which in turn is fixedly mounted to a structure not shown.

[0037] The spherical structure 102 is rotatably coupled to the frame 702 and is rotatable relative to the non-magnetic structure 106. Specifically, it is mounted to rotate relative to the non-magnetic structure 106 at least about a first axis of symmetry 110-1 and a second axis of symmetry 110-2. In some embodiments, such as in Figure 7 and Figure 8In the embodiment shown, the spherical structure 102 can also be mounted to rotate relative to the non-magnetic structure 106 about a third axis of symmetry 110-3. To provide this function, the spherical structure 102 has a ball socket 704 formed therein. The ball socket 704 receives a ball socket joint 706 formed on one end of the shaft 708. The shaft 708 is fixedly coupled to the frame 702 at its other end and extends radially inward from the frame 702.

[0038] exist Figure 7 and Figure 8 The illustrated embodiment may also include a device mounting shaft 712. When included, the device mounting shaft 712 is fixedly coupled to the spherical structure 102 and thus rotatable therewith. For example, the device mounting shaft 712 may be coupled to the spherical structure 102 by means of threads, press fit, or adhesive. Various devices, including but not limited to one or more cameras, one or more sensors, or thrusters, may be coupled to the device mounting shaft 712 and rotatable therewith.

[0039] Compared to currently known multi-degree-of-freedom electromagnetic machines, the electromagnetic machine 100 disclosed herein offers unexpected improvements. For example, currently known multi-degree-of-freedom electromagnetic machines exhibit a holding torque of approximately 0.019 Nm, while the electromagnetic machine 100 disclosed herein unexpectedly provides a holding torque of 0.024 Nm. Furthermore, currently known multi-degree-of-freedom electromagnetic machines exhibit a minimum position error of approximately 1.5 degrees. However, this electromagnetic machine unexpectedly exhibits a position error of only 0.15 degrees. The electromagnetic machine 100 disclosed herein exhibits a near-sinusoidal air gap magnetic flux density, as in... Figure 7 As shown. Conversely, as... Figure 8 As shown, the air gap magnetic flux density exhibited in currently known multi-degree-of-freedom electromagnetic machines is highly non-sinusoidal. Furthermore, as... Figure 9 As shown, the torque-position relationship 902 exhibited by the electromagnetic machine 100 disclosed herein is significantly and unexpectedly smoother than that of the currently known multi-degree-of-freedom electromagnetic machine 904.

[0040] In this document, relational terms such as "first" and "second" may be used only to distinguish one entity or action from another, and do not necessarily require or imply any actual such relationship or order between such entities or actions. Unless expressly defined by the language of the claims, numerical ordinal numbers such as "first," "second," "third," etc., merely indicate different individuals among a plurality and do not imply any order or sequence. Unless expressly defined by the language of the claims, any sequence of text in the claims does not imply that the processing steps must be performed in a chronological or logical order according to such a sequence. Without departing from the scope of the invention, the method steps may be interchanged in any order, provided that such interchange does not contradict the language of the claims and is not logically absurd.

[0041] Furthermore, depending on the context, the use of terms such as “connected” or “coupled to” when describing the relationship between different components does not imply that a direct physical connection must be made between these components. For example, two components can be physically, electronically, logically, or in any other way connected to each other by one or more additional components.

[0042] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be understood that numerous variations exist. It should also be understood that one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or construction of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing exemplary embodiments of the invention. It should be understood that various changes can be made to the function and arrangement of the elements described in the exemplary embodiments without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A multi-degree-of-freedom electromagnetic machine, comprising: A spherical structure having a first axis of symmetry, a second axis of symmetry, and a third axis of symmetry, wherein the first axis of symmetry, the second axis of symmetry, and the third axis of symmetry are arranged perpendicular to each other; A first coil is wound around the spherical structure about the first axis of symmetry; A second coil is wound around the spherical structure about the second axis of symmetry; A non-magnetic structure, which is spaced apart from and at least partially surrounds the spherical structure; A frame rotatably connected to the spherical structure and the non-magnetic structure, such that (i) the non-magnetic structure and the frame can rotate together relative to the spherical structure about a first axis of symmetry, and (ii) the non-magnetic structure can rotate relative to the frame and the spherical structure about a second axis of symmetry; and A Helbeck array mounted on the non-magnetic structure, the Helbeck array comprising N magnets, where N is a multiple of 4. The spherical structure and the non-magnetic structure are mounted to allow relative rotation between the non-magnetic structure and the spherical structure. The framework mentioned above includes: Install flange; A fixed shaft extends through the spherical structure and is fixedly connected to both the mounting flange and the spherical structure; A lower magnetic yoke, rotatably coupled to the shaft and rotatable relative to the shaft and the mounting flange about the first axis of symmetry; and An upper yoke, rotatably connected to the shaft, is connected to the lower yoke and is capable of rotating together with the lower yoke. The non-magnetic structure includes: main body; A first shaft portion, extending radially outward from the main body and rotatably mounted between the lower yoke and the upper yoke; and A second shaft portion extends radially outward from the main body and is diametrically opposed to the first shaft portion, and is rotatably mounted between the lower yoke and the upper yoke.

2. The electromagnetic machine according to claim 1, wherein: The non-magnetic structure comprises one of aluminum and plastic; and N equals 16.

3. The electromagnetic machine according to claim 1, wherein the non-magnetic structure is mounted to rotate relative to the spherical structure about the first axis of symmetry and the second axis of symmetry.

4. The electromagnetic machine according to claim 1, further comprising: A first bearing assembly is mounted on the fixed shaft and connected to the lower magnetic yoke; and The second bearing assembly is mounted on the fixed shaft and connected to the upper magnetic yoke.

5. The electromagnetic machine according to claim 4, further comprising: A third bearing assembly is mounted on the first shaft and connected to the lower yoke and the upper yoke; and A fourth bearing assembly is mounted on the second shaft and connected to the lower yoke and the upper yoke.

6. The electromagnetic machine according to claim 1, further comprising: A frame, rotatably connected to the spherical structure and fixedly connected to the non-magnetic structure, such that the spherical structure is capable of rotating relative to the frame and the non-magnetic structure at least about the first axis of symmetry and the second axis of symmetry; A spherical cavity, wherein the spherical cavity is formed in the spherical structure; and A shaft having a first end and a second end and extending radially inward from the frame, the first end being coupled to the frame, and the second end having a ball joint formed thereon, the ball joint being disposed within the ball socket.

7. The electromagnetic machine according to claim 1, further comprising: A third coil is wound around the spherical structure about the third axis of symmetry.

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