Motor and article

Abstract

To provide a magnetic levitation device capable of performing stable rotation control.SOLUTION: A motor including a rotation unit and a fixed unit, the motor comprising: a scale provided on one of the rotation unit and the fixed unit; a rotation angle detection unit provided on the other of the rotation unit and the fixed unit and configured to detect a rotation angle by reading the scale; a position detection unit configured to detect a position of the rotation unit; and a control unit configured to control the rotation unit based on a rotation angle for control derived from the rotation angle and the position.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to motors and articles. [Background technology]

[0002] In magnetic levitation control, where the rotor (rotating part) is supported by the stator (fixed part) without contact, planar control, which controls the rotor's position on a plane perpendicular to the rotation axis, and rotation control of the rotor along the rotation axis are simultaneously performed. Planar control controls the rotor's planar position by detecting the distance to the rotor using a position detection unit (displacement sensor, etc.) attached to the stator. Rotation control controls the rotation direction by detecting the rotation angle using an angle detection unit (optical encoder, etc.) attached to the stator that reads the detected part (optical scale, etc.) attached to the rotor.

[0003] As an example of planar control, when the rotor is transitioned from a seated state to a levitated state, the controller calculates the rotor's current position from the value of the position detector read every control cycle, calculates the required torque from the difference with the target position, and passes a current corresponding to the torque through the coil to transition to the levitated state.

[0004] Patent Document 1 discloses a technology in which a rotor is levitated and supported by electromagnets, the radial and axial positions of the rotor are detected by sensors, and the power supply to the electromagnets is controlled so that the rotor is levitated and supported concentrically with the center of the stator. Patent Document 2 discloses a method in which a movable frame provided on the stator is used to solve the problem of the rotor's center of rotation being shifted when zero power control is performed on a rotor rotating inside a stator. These technologies enable effective planar control of the rotor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-168619 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-249852 Summary of the Invention [Problem to be solved by the invention]

[0006] If a displacement of the plane occurs when rotation control is performed in addition to planar control, the angle detection means may erroneously recognize that the rotor has rotated, and the rotation angle may not be calculated accurately. [Means for solving the problem]

[0007] One embodiment of the present disclosure is a motor having a rotating unit and a fixed unit, comprising: a scale provided on one of the rotating unit and the fixed unit; a rotation angle detection unit provided on the other of the rotating unit and the fixed unit and detecting a rotation angle by reading the scale; a position detection unit that detects a position of the rotating unit; and a control unit that controls the rotating unit, wherein the control unit controls the rotating unit based on a control rotation angle derived from the rotation angle and the position. [Effects of the Invention]

[0008] According to at least one embodiment of the present disclosure, an accurate rotation angle of the rotor can be obtained, and stable magnetic levitation control can be performed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram illustrating rotation angle detection using an optical encoder according to the first embodiment. [Figure 2] 1 is a schematic diagram showing the overall configuration of a magnetic levitation device according to a first embodiment. [Figure 3] FIG. 1 is a schematic diagram according to a first embodiment. [Figure 4] FIG. 1 is a schematic diagram according to a first embodiment. [Figure 5] FIG. 10 is a schematic diagram according to a second embodiment. [Figure 6] FIG. 10 is a schematic diagram according to a third embodiment. [Figure 7] FIG. 10 is a schematic diagram showing the arrangement of scales according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) The first embodiment will be described below with reference to Figures 1 to 4. In the following description, the -Z direction in the figures is the direction of gravity.

[0011] First, we will explain the phenomenon in which a displacement on a plane is recognized as a rotation of the rotor using Figure 1. Figure 1 is a diagram that shows a schematic diagram of the stator and rotor that make up a magnetic levitation device. In Figure 1, the coordinate axes are +X to the right, +Z upward, and +ThY clockwise.

[0012] Stator 11 is a fixed part having a coil array 12 for controlling the position and rotation angle of rotor 21. Rotor 21 is a rotating part having a magnet array 22 in the circumferential direction. Electromagnetic forces acting between coil array 12 and magnet array 22 enable planar control in at least the XZ plane and rotation control around the rotation axis.

[0013] The rotor 21 has an optical scale 32 arranged in a circular ring shape on the XZ plane (i.e., on the bottom surface of the cylindrical rotor 21). The optical scale 32 has, for example, a configuration in which light-reflecting portions (white) and light-transmitting portions (black) are arranged alternately.

[0014] The stator 11 has an optical encoder 31 attached to the circumference of an optical scale 32. The optical encoder 31 emits light toward the optical scale 32 and detects a change in the reflected light from the optical scale 32 that occurs when the rotor 21 operates, thereby recognizing that the rotor 21 has rotated.

[0015] 1, optical encoder 31 is used to detect that rotor 21 has rotated around the rotation axis. However, when planar control and rotation control are performed simultaneously, the value detected by optical encoder 31 changes depending on the displacement of the planar surface and the displacement of the rotation angle, making it difficult to detect only the rotation angle separately.

[0016] For example, if the rotor 21 does not rotate but a small displacement occurs in the planar direction, the reflected light from the optical scale 32 detected by the optical encoder 31 may change, which may result in a false recognition that rotation has occurred. If such a false recognition occurs, control may be performed to return the falsely recognized rotation to its original state, even though no rotation has occurred.

[0017] Figure 2 is a schematic diagram of the overall configuration of the magnetic levitation device according to this embodiment. In Figure 2(a), the coordinate axes are +X to the right, +Z upward, +Y from the front to the back, and +ThY clockwise. In Figure 2(b), the coordinate axes are +Y to the right, +Z upward, and +X from the back to the front.

[0018] The magnetic levitation device is composed of a stator 11, a rotor 21, and a control unit 51. The stator 11 has two coil arrays 12 on its top surface (+Z direction) that are offset in the Y-axis direction. The stator 11 has bearing members 13 at two locations, one at the front and one at the back in the Y-axis direction, that extend from its bottom surface (-Z direction) in the +Z direction. The bearing member 13 has a hole in the part that becomes the rotation axis, and receives the shaft portion of the rotor 21.

[0019] The stator 11 has an optical encoder 31 at a position facing the optical scale 32. The optical encoder 31 detects the optical scale 32 to obtain the rotation angle of the rotor 21.

[0020] Stator 11 has an X sensor 41. The position of rotor 21 in the X direction is measured by detecting the distance from X sensor 41 to the surface of rotor 21. Stator 11 also has a Z sensor 42, and the position of rotor 21 in the Z direction is measured by detecting the distance from Z sensor 42 to the surface of rotor 21.

[0021] The rotor 21 has two magnet rows 22 arranged along the circumferential direction of its side surface. The magnet rows 22 are arranged to face the coil rows 12. The rotor 21 also has an optical scale 32 arranged in an annular shape on the XZ plane. The rotor 21 also has a shaft portion that abuts against the bearing member 13 at two points in the Y-axis direction.

[0022] The coil array 12 and the magnet array 22 are arranged in the circumferential direction around the rotation axis. The electromagnetic force generated by the current flowing through the coil array 12 acts on the two sets of coil arrays 12 and magnet arrays 22, enabling planar control in at least the XZ plane and rotational control on the ThY axis.

[0023] The control unit 51 has an acquisition unit 52 and a driver 53. The acquisition unit 52 acquires the values ​​of the optical encoder 31, the X sensor 41, and the Z sensor 42 at predetermined intervals. The control unit 51 also calculates a current value that realizes a desired operation and inputs it to the driver 53. The driver 53 controls the current value of the coil array 12, thereby controlling the rotor 21 by the electromagnetic force with the magnet array 22.

[0024] Using Figure 3, we will derive equations for calculating the positional displacement DS and rotational displacement DE when the rotor 21 moves in the planar direction and rotational direction. In Figure 3, the coordinate axes are +X to the right, +Z upward, and +ThY clockwise.

[0025] The rotor 21 has an optical scale 32 on the XZ plane. The stator 11 has an encoder E on the circumference of the optical scale 32. The encoder E detects the optical scale 32 to obtain the rotation angle.

[0026] The stator 11 has a sensor S positioned so that its distance measurement axis is perpendicular to the rotation axis of the rotor 21, and obtains the distance to the surface of the rotor 21 as seen from the sensor S. In other words, the sensor S is a position detection unit that detects the position of the rotor 21. The detection axis of the sensor S and the detection axis of the encoder E are arranged perpendicular to each other. Here, "perpendicular" does not only mean that the detection axis of the sensor S and the detection axis of the encoder E are at 90°, but also includes cases where they are substantially perpendicular, including actual installation errors of the sensor S and the encoder E. For example, a state including an error of about ±1° is also considered to be "perpendicular."

[0027] The control unit 51 acquires the values ​​of the sensor S and the encoder E at every predetermined period. The control unit 51 also stores the acquired values ​​of the sensor S and the encoder E. The control unit 51 derives a displacement DS, which is the difference between the first rotation angle and the second rotation angle acquired from the sensor S at every predetermined period, and a displacement DE of the encoder E, which is the difference between the first position and the second position acquired from the encoder E at every predetermined period.

[0028] Considering the negative side of the X axis as the reference axis and clockwise as the positive direction as the installation angle reference axis, Th_E is the installation angle of encoder E, and Th_S is the installation angle of sensor S. DX is the displacement in the X direction that occurs in rotor 21. Also, DZ is the displacement in the Z direction that occurs in rotor 21. Also, DR is the rotational displacement in the ThY direction that occurs in rotor 21. r is the distance from the center of rotation of rotor 21 to the installation position of encoder E.

[0029] At this time, the displacement DE of the value of the encoder E is expressed by the following equation 1. DE=DX·sin(Th_E)+DZ·cos(Th_E)+r·DR (Equation 1)

[0030] The change DS in the value of the sensor S is expressed by the following equation 2. DS=DZ·sin(Th_S)-DX·cos(Th_S) (Equation 2) Using Fig. 4, the method by which the control unit 51 calculates the control rotation angle DR from Equation 1 will be shown. Fig. 4 is a diagram showing a case where the mounting angle Th_E of sensor E and the mounting angle S of sensor S are different from those in Fig. 3. Fig. 4 shows a case where the mounting angle Th_E of sensor E and the mounting angle Th_S of sensor S are not (π / 2)*n (n is an integer), that is, a case where the mounting positions of sensors E and S are not on the X-axis or Z-axis.

[0031] The value of the setting angle Th_E is π because the encoder E is placed on the positive side of the X axis. Also, the value of the setting angle Th_S is (π / 2) because the sensor S is placed on the positive side of the Z axis. Therefore, Th_S can be expressed by the following equation 3. Th_S=Th_E-π / 2 (Equation 3)

[0032] Here, by substituting Equation 3 into Equation 2, we obtain Equation 4 below. DS=-DZ·cos(Th_E)-DX·sin(Th_E) (Equation 4)

[0033] Furthermore, by adding and transforming Equation 1 and Equation 4, we obtain Equation 5 below. DR=(DE+DS) / r (Equation 5) Equation 5 shows that when the mounting angle between encoder E and sensor S is a right angle and Th_E is larger than Th_S, the control rotation angle DR can be derived from the sum of the displacement DE of encoder E and the displacement DS of sensor S.

[0034] On the other hand, when the mounting angle between the encoder E and the sensor S is a right angle and Th_E is smaller than Th_S, Th_S can be expressed by the following equation 6. Th_S=Th_E+π / 2 (Equation 6)

[0035] Substituting Equation 6 into Equation 2, we obtain Equation 7 below. DS=DZ·cos(Th_E)+DX·sin(Th_E) (Equation 7)

[0036] By subtracting Equation 7 from Equation 1 and rearranging it, we obtain Equation 8 below. DR=(DE−DS) / r…(Equation 8) Equation 8 shows that when the mounting angle between encoder E and sensor S is a right angle and Th_E is smaller than Th_S, the control rotation angle DR can be derived from the difference between the displacement DE of encoder E and the displacement DS of sensor S.

[0037] Furthermore, even if the mounting angle Th_E of encoder E and the mounting angle Th_S of sensor S are not (π / 2)*n (n is an integer), that is, if the mounting position is not on the X-axis or Z-axis, the control rotation angle DR can be calculated using the above formula. Specifically, if Th_E-Th_S is +π / 2, the control rotation angle DR can be calculated using formula 5, and if it is -π / 2, the control rotation angle DR can be calculated using formula 8.

[0038] The control rotation angle DR derived as described above is a rotation angle in which the influence of displacement in the XZ plane of the rotor 21 is reduced. By performing rotation control using this control rotation angle DR, stable magnetic levitation control can be performed.

[0039] (Second embodiment) The second embodiment will be described below with reference to FIG. 5. In FIG. 5, the coordinate axes are +X for the right direction, +Z for the upward direction, and +ThY for the clockwise direction. The second embodiment is a case in which two sensors are arranged to detect the position of the rotor 21 in the XZ plane. For example, even if the encoder and the sensor cannot be arranged orthogonally due to various constraints such as the arrangement of the magnetic levitation device, the rotation angle can be derived by using one encoder and two sensors that measure the position of the rotor 21.

[0040] The rotor 21 has an optical scale 32 on the XZ plane. The stator 11 has an encoder E on the circumference of the optical scale 32. The encoder E detects the optical scale 32 to obtain the rotation angle DE.

[0041] Stator 11 has sensor S1 at a position where its distance measurement axis is perpendicular to the rotation axis of rotor 21. The distance to the surface of rotor 21 as seen from sensor S1 is obtained. Stator 11 has sensor S2 at a position where its distance measurement axis is perpendicular to the rotation axis of rotor 21. The distance to the surface of rotor 21 as seen from sensor S2 is obtained.

[0042] The control unit 51 acquires the values ​​of the encoder E, the sensor S1, and the sensor S2 at predetermined intervals. The control unit 51 also stores the acquired values ​​of the encoder E, the sensor S1, and the sensor S2. The control unit 51 also derives a displacement DE from the value detected by the encoder E, a displacement DS1 from the value detected by the sensor S1, and a displacement DS2 from the value detected by the sensor S2.

[0043] When the negative side of the X-axis is used as the reference and the clockwise direction is the positive direction, Th_E is the mounting angle of encoder E, Th_S1 is the mounting angle of sensor S1, and Th_S2 is the mounting angle of sensor S2.

[0044] DX is the displacement in the X-axis direction that occurs in the rotor 21. DZ is the displacement in the Z-axis direction that occurs in the rotor 21. DR is the rotational displacement in the ThY-axis direction that occurs in the rotor 21. r is the distance from the center of rotation of the rotor 21 to the installation position of the encoder E.

[0045] The displacement DE of the value of the encoder E is expressed by the above-mentioned formula 1. Furthermore, the displacement DS1, which is the change in the value of the sensor S1, is expressed by the following formula 9. DS1=DZ·sin(Th_S1)-DX·cos(Th_S1) (Equation 9)

[0046] Further, the displacement DS2, which is the change in the value of the sensor S2, is expressed by the following equation 10. DS2=DZ·sin(Th_S2)-DX·cos(Th_S2) (Equation 10)

[0047] By simultaneously solving Equation 9 and Equation 10, the following Equations 11 and 12 are obtained. DX=(DS1·sin(Th_S2)-DS2·sin(Th_S1)) / sin(Th_S1-Th_S2) (Equation 11) DZ=(DS2·sin(Th_S1)-DS1·sin(Th_S2)) / sin(Th_S1-Th_S2) (Equation 12) Here, if the sensors S1 and S2 face each other, the denominators of the formulas 11 and 12 become 0. Therefore, when the control rotation angle is determined using a pair of sensors as in this embodiment, the sensors need to be positioned so that they do not face each other.

[0048] Substituting equations 11 and 12 into equation 1 and rearranging, we obtain equation 13 below. DR=DE / r+{(sin(Th_E)-cos(Th_E))·(DS2·sin(Th_S1)-DS1·sin(Th_S2)) / (r·sin(Th_S1-Th_S2))} (Equation 13) Equation 13 can be used to derive the control rotation angle DR when two sensors, sensor S1 and sensor S2, are provided. Even if the encoder and sensor cannot be arranged orthogonally, using two sensors makes it possible to derive a rotation angle that is free from the effects of displacement of the rotor 21 in the XZ plane.

[0049] (Third embodiment) The third embodiment will be described below with reference to Fig. 6. The coordinate axes are +X for the right direction, +Z for the up direction, and +ThY for the clockwise direction.

[0050] For example, even if it is not possible to place a sensor outside the rotor due to various constraints such as the placement of the magnetic levitation device, the rotation angle can be derived by using two diagonally placed encoders.

[0051] The rotor 21 has an optical scale 32 on the XZ plane. The stator 11 has encoders E1 and E2 on the circumference of the optical scale 32. The encoder E1 detects the optical scale 32 to obtain a rotation angle. The encoder E2 detects the optical scale 32 to obtain a rotation angle.

[0052] The control unit 51 acquires the values ​​of the encoders E1 and E2 at predetermined intervals. The control unit 51 also stores the acquired values ​​of the encoders E1 and E2. The control unit 51 also stores the acquired values ​​of the encoders E1 and E2. The control unit 51 derives a displacement DE1 from the value detected by the encoder E1 and a displacement DE2 from the value detected by the encoder E2.

[0053] When the negative side of the X-axis is used as the reference axis for the setting angle and clockwise is the positive direction, Th_E1 is the setting angle of encoder E1, and Th_E2 is the setting angle of encoder E2. E1 and E2 are arranged diagonally, and Th_E1 is expressed by the following equation 15. Th_E1=Th_E2-π (Equation 15)

[0054] DX is the displacement in the X-axis direction that occurs in the rotor 21. DZ is the displacement in the Z-axis direction that occurs in the rotor 21. DR is the rotational displacement in the ThY-axis direction that occurs in the rotor 21. r is the distance from the center of rotation of the rotor 21 to the installation position of the encoder E.

[0055] The displacement DE1 of the value of the encoder E1 is given by the following equation 16. DE1=DX·sin(Th_E1)+DZ·cos(Th_E1)+r·DR (Equation 16)

[0056] The displacement DE2 of the value of the encoder E2 is given by the following equation 17. DE2=DX·sin(Th_E2)+DZ·cos(Th_E2)+r·DR (Equation 17)

[0057] Substituting Equation 15 into Equation 16, we obtain Equation 18 below. DE1=-DX·sin(Th_E2)-DZ·cos(Th_E2)+r·DR (Equation 18)

[0058] Adding and transforming equations 17 and 18, we obtain equation 19 below. DR=(DE1+DE2) / 2r (Equation 19) The control rotation angle DR when two encoders are provided can be derived using equation 19. Even in cases where it is not possible to place a sensor on the outside of the rotor, by using two diagonally arranged encoders, it is possible to derive a rotation angle that is free from the influence of displacement of the rotor 21 in the XZ plane.

[0059] (Other embodiments) The technology of the present disclosure is not limited to the embodiments described above, and modifications are possible within the technical concept of the present disclosure. For example, the motors of the first to third embodiments may function as components of an item that requires rotational force.

[0060] 7, the optical scale 32 may be provided on the outer periphery of the rotor 21 (i.e., on the cylindrical side surface of the cylindrical rotor 21). In this case, the detection axis of the optical encoder 31 is disposed in a direction perpendicular to the Y axis. The optical encoder 31 detects the optical scale 32 from the +X axis side with the detection axis parallel to the X axis.

[0061] Furthermore, in each of the above embodiments, a configuration has been described in which the coil array 12 of the stator 11 is provided on the outside and the magnet array 22 of the rotor 21 is provided on the inside, but for example, a configuration in which the coil array 12 of the stator 11 is provided on the inside and the magnet array 22 of the rotor 21 is provided on the outside may also be used.

[0062] In addition, in the above embodiments, the difference between the previous value and the current value is used to calculate the displacement of the encoder or sensor value, but this is not limited to this. For example, a pre-stored ideal position and rotation angle may be stored as a reference position and reference rotation angle, respectively, and the difference between the acquired value and the reference position and reference rotation angle may be used as the displacement to derive the control rotation angle DR.

[0063] Furthermore, in each of the above embodiments, an optical encoder is used as the rotation angle detection unit and an optical scale is used as the detected unit, but other known means such as a magnetic encoder or a magnetic scale may also be used.

[0064] Alternatively, the rotor 21 may have a rotation angle detection unit such as the optical encoder 31, and the stator 11 may have a detected unit such as the optical scale 32. In other words, it is sufficient that the rotation angle detection unit is provided on either the rotor or stator side, and the detected unit is provided on the other side.

[0065] Alternatively, the magnet array 22 may be provided on the rotor side, and the coil array 12 may be provided on the stator side.

[0066] Furthermore, although the rotation axis of the rotor is the ThY axis, the rotation axis may be tilted.

[0067] The disclosure of this embodiment includes the following configuration.

[0068] (Item 1) A motor having a rotating part and a fixed part, a scale provided on one of the rotating part and the fixed part; a rotation angle detection unit that is provided on the other of the rotating unit and the fixed unit and detects a rotation angle by reading the scale; a position detection unit that detects the position of the rotating unit; a control unit that controls the rotating unit, The motor, wherein the control unit controls the rotating unit based on a control rotation angle derived from the rotation angle and the position.

[0069] (Item 2) 2. The motor according to item 1, wherein the scale is provided on the rotating part, and the rotation angle detection part is provided on the fixed part.

[0070] (Item 3) 2. The motor according to item 1, wherein the scale is provided on the fixed part, and the rotation angle detection part is provided on the rotating part.

[0071] (Item 4) 3. The motor according to item 2, wherein the scale is provided on a side surface of the rotating part.

[0072] (Item 5) 3. The motor according to item 2, wherein the scale is provided on the bottom surface of the rotating part.

[0073] (Item 6) The control unit As the rotation angles, a first rotation angle and a second rotation angle are acquired based on a predetermined cycle; deriving a displacement of the rotation angle using the first rotation angle and the second rotation angle; Deriving the control rotation angle using the change in the rotation angle. 6. The motor according to any one of items 1 to 5,

[0074] (Item 7) The control unit As the positions, a first position and a second position are acquired based on a predetermined period; deriving a displacement of the position using the first position and the second position; Deriving the control rotation angle using the positional displacement. 6. The motor according to any one of items 1 to 5,

[0075] (Item 8) a reference rotation angle that is a reference for the rotation angle; The control unit derives the control rotation angle using the acquired rotation angle and the reference rotation angle. 8. The motor according to any one of items 1 to 7, characterized in that:

[0076] (Item 9) a reference position that serves as a reference for the position; The control unit derives the control rotation angle using the acquired position and the reference position. 8. The motor according to any one of items 1 to 7, characterized in that:

[0077] (Item 10) 10. The motor according to any one of items 1 to 9, wherein the control unit simultaneously controls the rotation of the rotating unit and the levitation of the rotating unit.

[0078] (Item 11) 11. The motor according to any one of items 1 to 10, wherein the detection axis of the position detection unit and the detection axis of the rotation angle detection unit are orthogonal to each other.

[0079] (Item 12) Item 12. The motor according to item 11, wherein the position detection unit detects displacement in the direction of gravity.

[0080] (Item 13) 13. The motor according to any one of items 1 to 12, wherein the position detector includes a plurality of position detectors, and at least one pair of the plurality of position detectors does not face each other.

[0081] (Item 14) 14. The motor according to any one of items 1 to 13, wherein the rotation angle detection unit is an optical encoder.

[0082] (Item 15) 14. The motor according to any one of items 1 to 13, wherein the rotation angle detection unit is a magnetic encoder.

[0083] (Item 16) An article comprising the motor according to any one of items 1 to 15. [Explanation of symbols]

[0084] 11 Stator 21 rotor 31 Optical Encoder 32 Optical scale 41 X Sensor 42 Z sensor 51 Control section

Claims

1. A motor having a rotating part and a fixed part, a scale provided on one of the rotating part and the fixed part; a rotation angle detection unit that is provided on the other of the rotating unit and the fixed unit and detects a rotation angle by reading the scale; a position detection unit that detects the position of the rotating unit; a control unit that controls the rotating unit, The motor, wherein the control unit controls the rotating unit based on a control rotation angle derived from the rotation angle and the position.

2. 2. The motor according to claim 1, wherein the scale is provided on the rotating part, and the rotation angle detection part is provided on the fixed part.

3. 2. The motor according to claim 1, wherein the scale is provided on the fixed portion, and the rotation angle detection portion is provided on the rotating portion.

4. 3. The motor according to claim 2, wherein the scale is provided on a side surface of the rotating portion.

5. 3. The motor according to claim 2, wherein the scale is provided on a bottom surface of the rotating portion.

6. The control unit As the rotation angles, a first rotation angle and a second rotation angle are acquired based on a predetermined period; deriving a displacement of the rotation angle using the first rotation angle and the second rotation angle; Deriving the control rotation angle using the change in the rotation angle.

2. The motor according to claim 1,

7. The control unit As the positions, a first position and a second position are acquired based on a predetermined period; deriving a displacement of the position using the first position and the second position; Deriving the control rotation angle using the positional displacement.

2. The motor according to claim 1,

8. a reference rotation angle that is a reference for the rotation angle; The control unit derives the control rotation angle using the acquired rotation angle and the reference rotation angle.

2. The motor according to claim 1,

9. a reference position that serves as a reference for the position; The control unit derives the control rotation angle using the acquired position and the reference position.

2. The motor according to claim 1,

10. 2. The motor according to claim 1, wherein the control unit simultaneously controls the rotation of the rotating unit and the levitation of the rotating unit.

11. 2. The motor according to claim 1, wherein the detection axis of the position detection unit and the detection axis of the rotation angle detection unit are orthogonal to each other.

12. The motor according to claim 11, wherein the position detector detects displacement in the direction of gravity.

13. 2. The motor according to claim 1, wherein the position detector comprises a plurality of position detectors, and at least one pair of the plurality of position detectors does not face each other.

14. 2. The motor according to claim 1, wherein the rotation angle detection unit is an optical encoder.

15. 2. The motor according to claim 1, wherein the rotation angle detection unit is a magnetic encoder.

16. An article comprising a motor according to any one of claims 1 to 15.

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