A flux switching permanent magnet spherical motor based on motion decoupling

Abstract

The invention discloses a flux switching permanent magnet spherical motor based on motion decoupling, wherein the stator structure is composed of a stator spherical shell and stator pole pairs fixedly arranged on the inner surface of the stator spherical shell; two U-shaped stator pole teeth clamp the permanent magnet with their own side edges, and are wound with windings to form stator pole pairs, and the stator pole pairs are divided into spin module pole pairs and tilt module pole pairs according to different positions on the inner surface of the stator spherical shell; the rotor structure is composed of a rotor spherical shell and rotor pole teeth fixedly arranged on the rotor spherical shell, the rotor spherical shell is a hollow magnetic conductive sphere, and the rotor pole teeth are cylindrical pole teeth made of magnetic conductive material; each cylindrical pole tooth is independently embedded in the rotor spherical shell; the output shaft is fixedly connected to the rotor spherical shell and extends radially along the rotor spherical shell; the invention adopts modular design based on motion decoupling, divides the stator pole pairs and the rotor pole teeth into spin motion modules and tilt motion modules, and thus realizes multi-degree-of-freedom motion.

Description

Technical Field

[0001] The invention relates to a spherical motor, and more particularly to a flux switching permanent magnet spherical motor based on motion decoupling. Background Art

[0002] Traditional multi-degree-of-freedom actuators are composed of two or more single-degree-of-freedom motors and complex transmission devices. The redundancy and complexity of their structures make them large in size. The complex transmission devices limit the improvement of control accuracy, and the system stiffness is also limited. For example, the motors used in robot joints are required to be small in size and have sufficiently large output torque, and traditional multi-degree-of-freedom actuators are difficult to apply to this.

[0003] At present, spherical motors are still in the laboratory research stage. There are various types of spherical motors based on different working principles, such as ultrasonic, permanent magnet, induction and reluctance types. Spherical motors have high integration, complex structure and strong coupling, which is not conducive to efficient and precise control of the motor. On the other hand, due to the limitations of their structure and driving principles, the output torque of spherical motors is often small. When running at high speed, the permanent magnets of the rotor will be thrown off due to the centrifugal force. Therefore, it is necessary to install a fixing device on the rotor, which brings about problems of heat dissipation difficulties and complex manufacturing processes. In addition, temperature rise may cause irreversible demagnetization of the permanent magnets, thereby limiting the output torque of the spherical motor. Summary of the invention

[0004] The present invention is to avoid the deficiencies of the above-mentioned prior art and to provide a flux switching permanent magnet spherical motor based on motion decoupling, which has high power density, large output torque, stable structure and good control effect. The motor can realize multi-degree-of-freedom motion by changing the on-off state, power size and power direction of the stator coil to affect the position of the magnetic flux path.

[0005] The present invention adopts the following technical solutions to solve the technical problems:

[0006] The present invention is based on the motion decoupling magnetic flux switching type permanent magnet spherical motor comprises a stator structure and a rotor structure, and its characteristics are:

[0007] The stator structure is composed of a stator spherical shell and stator magnetic pole pairs fixedly arranged on the inner surface of the stator spherical shell; two U-shaped stator magnetic pole teeth clamp the permanent magnet with their own side arms, and are wound with windings to form stator magnetic pole pairs in the form of a fan, and the stator magnetic pole pairs are divided into multiple groups of spin module magnetic pole pairs and multiple groups of tilt module magnetic pole pairs according to different positions on the inner surface of the stator spherical shell; the stator spherical shell is a non-magnetic spherical shell;

[0008] The rotor structure is composed of a rotor shell and rotor magnetic pole teeth fixedly arranged on the rotor shell. The rotor shell is a hollow magnetic conductive sphere. The rotor magnetic pole teeth are cylindrical magnetic pole teeth made of magnetic conductive material. Each cylindrical magnetic pole tooth is independently embedded in the rotor shell. The output shaft is fixedly connected to the rotor shell and extends in the radial direction of the rotor shell.

[0009] Based on motion decoupling, each spinning module pole pair in the stator pole pair and the rotor pole teeth constitute a spinning motion module, and each tilting module pole pair in the stator pole pair and the rotor pole teeth constitute a tilting motion module to achieve multi-degree motion.

[0010] The flux switching permanent magnet spherical motor based on motion decoupling of the present invention is also characterized in that:

[0011] The stator magnetic pole pairs include four groups of spin module magnetic pole pairs and four groups of tilt module magnetic pole pairs. All stator magnetic pole pairs are evenly arranged on the inner surface of the stator spherical shell along the inner circumference where the equator of the stator spherical shell is located, and the spin module magnetic pole pairs and the tilt module magnetic pole pairs are arranged alternately one by one, so that the four groups of spin module magnetic poles form a "cross" distribution, and the four groups of tilt module magnetic pole pairs are also in a "cross" distribution; the sector of each magnetic pole pair in the four groups of spin module magnetic pole pairs is parallel to the plane where the equator of the stator spherical shell is located; the sector of each magnetic pole pair in the four groups of tilt module magnetic pole pairs is perpendicular to the plane where the equator of the stator spherical shell is located;

[0012] The rotor magnetic pole teeth are distributed in seven layers on the surface of the rotor spherical shell at a layer interval of 16.36°, namely: a central layer of rotor magnetic pole teeth located at the equator of the rotor spherical shell, three upper layers of rotor magnetic pole teeth located above the equator of the rotor spherical shell, and three lower layers of rotor magnetic pole teeth located below the equator of the rotor spherical shell; 11 rotor magnetic pole teeth are evenly distributed in each layer, and the positions of the rotor magnetic pole teeth between the upper and lower adjacent layers are staggered.

[0013] The flux switching permanent magnet spherical motor based on motion decoupling of the present invention is also characterized in that the U-shaped stator magnetic pole teeth are fitted with the inner surface of the stator spherical shell with their arc-shaped bottom edges and are fixed to each other.

[0014] The flux switching permanent magnet spherical motor based on motion decoupling of the present invention is also characterized in that cylindrical grooves are arranged on the surface of the rotor spherical shell, and each rotor magnetic pole tooth is independently embedded in each cylindrical groove, so that the top of the rotor magnetic pole tooth is cospherical with the outer surface of the rotor spherical shell.

[0015] The flux switching permanent magnet spherical motor based on motion decoupling of the present invention is also characterized in that the polarity of the permanent magnets in the magnetic pole pairs of each rotating module is the same, and the polarity of the permanent magnets in the magnetic pole pairs of each tilting module is the same, and they all point from the U-shaped stator magnetic pole teeth on one side to the U-shaped stator magnetic pole teeth on the other side.

[0016] The characteristics of the flux switching permanent magnet spherical motor based on motion decoupling of the present invention are also that: the stator spherical shell is composed of two hemispherical shells matched together and fixed on the base by bolts, a ball bearing is arranged in the base, the rotor structure is supported on the ball bearing, and the ball bearing is installed in the screw hole of the base through a screw rod through a threaded connection, and the installation height is adjustable.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. The flux switching permanent magnet spherical motor based on motion decoupling of the present invention is small in size and simple to control. It can replace traditional multi-degree-of-freedom devices in some occasions with higher requirements, thereby reducing redundant structures, such as: in aerospace manipulators, robot joints, and in high-precision fields such as bionic eyes.

[0019] 2. The flux switching permanent magnet spherical motor of the present invention adopts a modular design. The stator pole pairs and rotor pole teeth responsible for the spin motion and tilt motion are independent of each other, and the two are organically combined to achieve multi-degree-of-freedom motion. Compared with the traditional spherical motor with multi-variable, strong coupling and complex drive control methods, it has good decoupling, which is conducive to the decoupling analysis of complex motion and easy to control.

[0020] 3. The flux switching permanent magnet spherical motor of the present invention is based on the flux switching principle. The flux path is switched by changing the current direction of the winding. When no power is supplied, the two U-shaped stator pole teeth in the stator pole pair are in a critical saturation state. After power is supplied, the side arms of the two U-shaped stator pole teeth form a flux path with the rotor pole teeth, generating electromagnetic force on the rotor pole teeth, and driving the motor to achieve multi-degree-of-freedom motion.

[0021] 4. In the present invention, the permanent magnets are all fixed in the stator, and the rotor only has rotor teeth made of magnetic conductive material, which has good heat dissipation effect and large output torque. By changing the coil ampere-turns, a larger output torque can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the flux switching permanent magnet spherical motor based on motion decoupling of the present invention;

[0023] Figure 2 It is a schematic diagram of the rotor structure and the output shaft structure in the present invention;

[0024] Figure 3 It is a schematic diagram of the structure of the stator magnetic pole pair in the present invention;

[0025] Figure 4 It is a schematic diagram of the arrangement of the stator magnetic pole pairs in the present invention;

[0026] Figure 5It is a schematic diagram of the rotor and stator magnetic pole pairs during the spin motion of the present invention;

[0027] Figure 6 It is a schematic diagram of the rotor and stator magnetic pole pairs during tilting motion of the present invention;

[0028] Figure 7 It is a schematic diagram of the corresponding relationship between the rotor rotation angle and the electromagnetic torque;

[0029] Figure 8 It is a schematic diagram of the corresponding relationship between the rotor tilting angle and the electromagnetic torque;

[0030] Numbers in the figure: 1 stator spherical shell, 2 permanent magnet, 3 stator magnetic pole teeth, 4 winding, 5 output shaft, 6 rotor spherical shell, 7 rotor magnetic pole teeth, 8 base, 9 ball bearing. DETAILED DESCRIPTION

[0031] See also Figure 1 In this embodiment, the flux switching permanent magnet spherical motor based on motion decoupling includes a stator structure and a rotor structure.

[0032] like Figure 1 , Figure 3 and Figure 4 As shown, the stator structure is composed of a stator spherical shell 1 and stator pole pairs fixedly arranged on the inner surface of the stator spherical shell 1; two U-shaped stator pole teeth 3 clamp the permanent magnet 2 with their own side arms, and wind the winding 4 to form a fan-shaped stator pole pair, and the stator pole pairs are divided into multiple groups of spin module pole pairs and multiple groups of tilt module pole pairs according to different positions on the inner surface of the stator spherical shell 1; the stator spherical shell 1 is a non-magnetic spherical shell; the permanent magnets and coils are arranged in the stator structure, which can effectively improve the stability of the motor structure and the heat dissipation effect, and avoid the risk of demagnetization of the permanent magnet due to the looseness of the permanent magnet or poor heat dissipation effect.

[0033] like Figure 1 and Figure 2 As shown, the rotor structure is composed of a rotor shell 6 and rotor pole teeth 7 fixedly arranged on the rotor shell 6. The rotor shell 6 is a hollow magnetic sphere, and the rotor pole teeth 7 are cylindrical pole teeth made of magnetic conductive material; each cylindrical pole tooth is independently embedded in the rotor shell 6; the rotor shell 6 is set as a hollow structure, which not only saves materials and reduces costs, but also effectively reduces the rotational inertia of the rotor structure itself, has higher efficiency and faster response speed, and there is no winding or other additional components in the rotor structure, and the structure is very stable.

[0034] The output shaft 5 is fixedly connected to the rotor shell 6 and extends radially of the rotor shell 6. The output shaft 5 is connected to the load. When the rotor structure moves, the output shaft 5 is driven to move, thereby driving the load. Based on motion decoupling, the magnetic pole pairs of each rotating module in the stator magnetic pole pair and the rotor magnetic pole teeth constitute a spinning motion module, and the magnetic pole pairs of each tilting module in the stator magnetic pole pair and the rotor magnetic pole teeth constitute a tilting motion module, so as to realize multi-degree motion.

[0035] Figure 1 The stator spherical shell 1 shown is composed of two hemispherical shells matched together and fixed on a base 8 by bolts. A ball bearing 9 is arranged in the base 8, and the rotor structure is supported on the ball bearing 9. The ball bearing 9 is installed in the screw hole of the base 8 through a threaded connection using a screw rod, and the installation height is adjustable. Figure 1 The top of the ball bearing 9 shown is a spherical universal ball with low friction and can rotate in any direction to ensure the multi-degree-of-freedom movement of the rotor structure; the lower part of the ball bearing 9 is a screw, which is installed in the screw hole of the base 8 to fix the ball bearing 9 and can be used to adjust the installation height; since the position of the rotor may be offset due to the manufacturing process and later operation, the center of the rotor structure and the center of the stator structure are not at the same point. At this time, the installation height of the ball bearing 9 is adjusted to make the center of the rotor structure consistent with the center of the stator structure.

[0036] In specific implementation, the corresponding structural measures also include:

[0037] like Figure 1 and Figure 4 As shown, the stator pole pairs include four groups of spin module pole pairs and four groups of tilt module pole pairs. Figure 4As shown in the figure, the first spin module magnetic pole pair A11 phase, the second spin module magnetic pole pair A12 phase, the third spin module magnetic pole pair A13 phase and the fourth spin module magnetic pole pair A14 phase, as well as the first tilt module magnetic pole pair B11 phase, the second tilt module magnetic pole pair B12 phase, the third tilt module magnetic pole pair B13 phase and the fourth tilt module magnetic pole pair B14 phase are respectively shown; all stator magnetic pole pairs are evenly arranged on the inner surface of the stator spherical shell 1 along the inner circumference where the equator of the stator spherical shell is located, and the spin module magnetic pole pairs and the tilt module magnetic pole pairs are arranged one by one, so that the four groups of spin module magnetic poles form a "cross" distribution, and the four groups of tilt module magnetic pole pairs are also in a "cross" distribution, the sector of each magnetic pole pair in the four groups of spin module magnetic pole pairs is parallel to the plane where the equator of the stator spherical shell 1 is located, and the permanent magnets in each spin module magnetic pole pair have the same polarity, which is from one side of the U-shaped stator magnetic pole tooth to the other side of the U shaped stator pole teeth; the sector of each pole pair in the four groups of tilted module pole pairs is perpendicular to the plane where the equator of the stator spherical shell 1 is located, and the permanent magnets in each tilted module pole pair have the same polarity, pointing from one side of the U-shaped stator pole teeth to the other side of the U-shaped stator pole teeth; the U-shaped stator pole teeth 3 are fitted with the inner surface of the stator spherical shell 1 with their arc-shaped bottom edges, and are fixed to each other; the arc-shaped bottom edges of the U-shaped stator pole teeth 3 are fitted with the inner surface of the stator spherical shell 1 to effectively ensure that the stator pole teeth are facing the center of the sphere; Figure 5 It is shown that the setting facing the center of the sphere can make the stator pole teeth and the rotor pole teeth face each other when the rotor pole teeth move below the stator pole teeth, and the distribution of the air gap magnetic field is more uniform and symmetrical.

[0038] like Figure 1 and Figure 2 As shown in the figure, the rotor pole teeth 7 are distributed in seven layers on the surface of the rotor spherical shell 6 at a layer interval of 16.36°, namely: a central layer of rotor pole teeth located at the equator of the rotor spherical shell 6, three upper layers of rotor pole teeth located above the equator of the rotor spherical shell 6, and three lower layers of rotor pole teeth located below the equator of the rotor spherical shell 6; 11 rotor pole teeth are evenly distributed in each layer, and the positions of the rotor pole teeth between the upper and lower adjacent layers are staggered; a cylindrical groove is provided on the surface of the rotor spherical shell 6, and each rotor pole tooth is independently embedded in each cylindrical groove, so that the top of the rotor pole tooth is co-spherical with the outer surface of the rotor spherical shell 6; the top surface of each rotor pole tooth is set as a spherical surface to ensure that when the rotor pole tooth and the stator pole tooth are facing each other, the length of the air gap at any position is consistent; in order to make the distribution of the rotor pole teeth 7 in the rotor spherical shell 6 clearer, Figure 2 , Figure 5 and Figure 6 The outer spherical surface of the rotor spherical shell 6 is not shown in the figure.

[0039] The motion of the multi-degree-of-freedom spherical motor of the present invention is achieved by the torque generated by the electromagnetic force interacting between the stator and the rotor. When the winding on the stator magnetic pole pair is not supplied with current, the permanent magnet 2 and the U-shaped magnetic pole teeth 3 on both sides and the rotor magnetic pole teeth 7 form a closed magnetic circuit, and the rotor structure has no electromagnetic torque at this time. When the winding on the stator magnetic pole pair is supplied with current in a certain direction, a magnetic flux switching is formed, and the two U-shaped magnetic pole teeth spaced apart form a magnetic flux path with the rotor magnetic pole teeth, which generates an electromagnetic tangential force on the rotor in the vicinity, thereby driving the rotor to move. When the winding on the stator magnetic pole pair is supplied with current in the opposite direction, the other two U-shaped magnetic pole teeth form a magnetic flux path with the rotor magnetic pole teeth to generate an electromagnetic tangential force. When the U-shaped magnetic pole teeth in the stator structure coincide with the rotor magnetic pole teeth, the torque is minimum. When the two deviate by a certain angle, the electromagnetic torque generated will cause the rotor magnetic pole teeth to move to the position where the two coincide. Due to the symmetry of the rotor structure and the stator structure, there is a certain symmetry during the spin and tilt motions.

[0040] See also Figure 5 The figure is a schematic diagram of the structure of the stator pole pairs and rotor pole teeth in the spin motion module. Taking the A12 phase of the second spin module pole pair as an example, when the coil winding is connected to the permanent magnet in the same direction, the coil generates a magnetic field. The coil magnetic field forms a magnetic flux path between the first side arm 31 and the second side arm 32 of the stator pole teeth and the horizontally adjacent first rotor pole teeth 71 and second rotor pole teeth 71 at the corresponding positions, thereby generating a tangential force on the rotor and driving the rotor to rotate. Similarly, the A11 phase, the A13 phase and the A14 phase cooperate with each other to energize the motor to complete the spin motion. The adjacent phases are connected to the reverse current, and the relative phases are connected to the same direction current, so that a larger torque can be obtained.

[0041] See also Figure 6 This is a schematic diagram of the stator pole pair and rotor pole teeth structure of the tilt motion module. Similar to the spin drive principle, current is passed through the stator pole pair coils, and different stator pole teeth and rotor pole teeth form a magnetic flux path to drive the rotor to achieve tilt motion. The figure shows that the B11 phase and the B13 phase cooperate to drive the tilt motion of one degree of freedom. Similarly, the B12 phase and the B14 phase cooperate to complete the tilt motion of another degree of freedom.

[0042] The drive units of the present invention are modularly and independently arranged, and the two are organically combined to achieve multi-degree-of-freedom motion; the modular drive unit has good decoupling compared to the complex drive control method of the traditional multi-degree-of-freedom spherical motor, which is conducive to the decoupling analysis of complex motion and easy to control. For spin and tilt motion, by adjusting the on and off and size of the winding coil current of different stator poles, the rotor can complete multi-degree-of-freedom stepping motion within a certain output range. The rotation of the rotor structure drives the output shaft to move, so that the load moves according to the designed motion mode.

[0043] Figure 7It is shown that when the stator pole pairs and multiple coils are energized, the maximum output torque of the rotor structure under spinning motion is increased by 150% compared with that of a single coil. Figure 8 It is shown that when the stator pole pairs and multiple coils are energized, the maximum output torque of the rotor structure under tilting motion is increased by 33% compared with that of a single coil.

[0044] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A flux switching permanent magnet spherical motor based on motion decoupling, comprising a stator structure and a rotor structure, characterized in that: The stator structure is composed of a stator spherical shell (1) and stator magnetic pole pairs fixedly arranged on the inner surface of the stator spherical shell (1); two U-shaped stator magnetic pole teeth (3) clamp the permanent magnet (2) with their own side arms, and are wound with windings (4) to form stator magnetic pole pairs in the form of a fan, and the stator magnetic pole pairs are divided into a plurality of groups of spin module magnetic pole pairs and a plurality of groups of tilt module magnetic pole pairs according to different positions on the inner surface of the stator spherical shell (1); the stator spherical shell (1) is a non-magnetic spherical shell; The rotor structure is composed of a rotor spherical shell (6) and rotor magnetic pole teeth (7) fixedly arranged on the rotor spherical shell (6); the rotor spherical shell (6) is a hollow magnetic conductive sphere; the rotor magnetic pole teeth (7) are cylindrical magnetic pole teeth made of magnetic conductive material; each cylindrical magnetic pole tooth is independently embedded in the rotor spherical shell; the output shaft (5) is fixedly connected to the rotor spherical shell (6) and extends in the radial direction of the rotor spherical shell (6); Based on motion decoupling, each spinning module magnetic pole pair in the stator magnetic pole pair and the rotor magnetic pole teeth constitute a spinning motion module, and each tilting module magnetic pole pair in the stator magnetic pole pair and the rotor magnetic pole teeth constitute a tilting motion module to achieve multi-degree motion; The stator magnetic pole pairs include four groups of spin module magnetic pole pairs and four groups of tilt module magnetic pole pairs. All stator magnetic pole pairs are evenly arranged on the inner surface of the stator spherical shell (1) along the inner circumference where the equator of the stator spherical shell is located, and the spin module magnetic pole pairs and the tilt module magnetic pole pairs are arranged alternately one by one, so that the four groups of spin module magnetic poles form a "cross" distribution, and the four groups of tilt module magnetic pole pairs are also in a "cross" distribution; the sector of each magnetic pole pair in the four groups of spin module magnetic pole pairs is parallel to the plane where the equator of the stator spherical shell (1) is located; the sector of each magnetic pole pair in the four groups of tilt module magnetic pole pairs is perpendicular to the plane where the equator of the stator spherical shell (1) is located; The rotor magnetic pole teeth (7) are distributed in seven layers on the surface of the rotor spherical shell (6) at a layer interval of 16.36 degrees, namely: a central layer of rotor magnetic pole teeth located at the equator of the rotor spherical shell (6), three upper layers of rotor magnetic pole teeth located above the equator of the rotor spherical shell (6), and three lower layers of rotor magnetic pole teeth located below the equator of the rotor spherical shell (6); 11 rotor magnetic pole teeth are evenly distributed in each layer, and the positions of the rotor magnetic pole teeth between two adjacent layers are staggered.

2. The flux switching permanent magnet spherical motor based on motion decoupling according to claim 1 is characterized in that: The U-shaped stator magnetic pole teeth (3) are fitted with the inner surface of the stator spherical shell (1) with their arc-shaped bottom edges and are fixed to each other.

3. The flux switching permanent magnet spherical motor based on motion decoupling according to claim 1 is characterized in that: The surface of the rotor spherical shell (6) is provided with a cylindrical groove, and each rotor magnetic pole tooth is independently embedded in each cylindrical groove, so that the top of the rotor magnetic pole tooth and the outer surface of the rotor spherical shell (6) are cospherical.

4. The flux switching permanent magnet spherical motor based on motion decoupling according to claim 1 is characterized in that: The permanent magnets in the magnetic pole pairs of each rotating module have the same polarity, and the permanent magnets in the magnetic pole pairs of each tilting module have the same polarity, and both point from the U-shaped stator magnetic pole teeth on one side to the U-shaped stator magnetic pole teeth on the other side.

5. The flux switching permanent magnet spherical motor based on motion decoupling according to claim 1 is characterized in that: The stator spherical shell (1) is composed of two hemispherical shells matched together and fixed on a base (8) by means of bolts. A ball bearing (9) is arranged in the base (8). The rotor structure is supported on the ball bearing (9). The ball bearing (9) is installed in a screw hole of the base (8) by means of a screw rod through a threaded connection, and the installation height is adjustable.

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