Electromagnetic device

Abstract

To provide an electromagnetic device capable of performing appropriate movement control of a moving body.SOLUTION: In a transport device 10, an armature part at a track portion is arranged with coil blocks each using three-phase coils 32, and a travel part made to be movable on an upper side of each of the coil blocks is arranged with a plurality of magnets. The coil blocks each are arranged with Hall sensors 42 (42U, 42V, 42W) linearly along a coil arrangement direction and at the same arrangement intervals. At a control part 50, the coils 32 are excited based on an electric angle θ, a d-axis current target value, and a q-axis current target value. In this case, a magnetic pole position calculation part 56 sets the electric angle θ based on the arrangement intervals of the Hall sensors 42, and magnetic flux densities detected by those, respectively. Thus, even when the travel part is tilted to a movement direction, and thus a yaw-angle is generated; the electric angle θ obtained by excluding influence on the yaw angle can be set, and appropriate excitation of the coils 32 and appropriate movement control of the travel part are made possible.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electromagnetic device.

Background Art

[0002] Patent Document 1 discloses an electric motor including a plate-shaped coil assembly including an elongated strip-shaped array of closely arranged bar-shaped permanent magnets and an array of flat coils arranged in the same direction as the permanent magnets.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a transport device or the like in which a linear motor is formed, coils are arranged in a stator, permanent magnets are arranged in a mover, and the coils are excited to move the mover. At this time, a plurality of Hall elements are arranged along the coil array, the magnetic flux density emitted from the mover is detected by each of the Hall elements, and an electrical angle is set based on the detection result.

[0005] However, if an inclination (yaw angle) occurs in the moving direction of the mover with respect to the arrangement direction of the coils, the magnetic flux density detected by each of the Hall elements changes. For this reason, there is a concern that an accurate electrical angle cannot be obtained, and it becomes difficult to appropriately excite the coils according to the position of the mover.

[0006] The present invention has been made in view of the above facts, and an object thereof is to provide an electromagnetic device that enables appropriate movement control of a moving body.

Means for Solving the Problems

[0007] To achieve the above object, an electromagnetic device according to a first aspect of the present invention includes a track portion extending along one direction, a moving body disposed opposite to the track portion and movably supported along a moving surface including the one direction by a supporting means, an armature portion in which a plurality of coil blocks each having coils corresponding to the number of phases are arranged in the one direction along the track portion, a field portion disposed on the moving body opposite to the coils of the armature portion, in which a plurality of permanent magnets are arranged in a direction corresponding to the one direction over one or a plurality of electrical angle cycles, and an end portion in a direction intersecting the arrangement direction of the permanent magnets faces an end portion in a direction intersecting the arrangement direction of the coils, a magnetic pole position detecting means that has the same positional intervals between the same positions within the coil blocks in a range of one electrical angle cycle or two electrical angle cycles, is arranged at three positions in parallel with the arrangement direction of the coils, and each detects a magnetic flux density corresponding to the magnetic pole position of the field portion, an electrical angle setting unit that sets an electrical angle indicating a position of a reference magnetic pole in the field portion with respect to the coil block based on signals indicating the magnetic flux densities detected by each of the magnetic pole position detecting means and the positional intervals of the magnetic pole position detecting means, and a control unit that sets a d-axis current target value and a q-axis current target value when moving the moving body along the one direction, and excites each of the coils of the coil blocks with a driving voltage corresponding to the electrical angle, the d-axis current target value, and the q-axis current target value.

[0008] In the electromagnetic device of the first aspect, the track portion facing the moving body extends along one direction, and the moving body is movably supported along a moving surface including the one direction by a supporting means. An armature portion is provided on the track portion, and a field portion facing the armature portion is provided on the moving body.

[0009] The armature portion is provided with coil blocks in which coils corresponding to the number of phases are arranged in one direction, and the plurality of coil blocks are arranged in one direction. Further, in the field portion, a plurality of permanent magnets are arranged in a direction corresponding to the one direction over one or a plurality of electrical angle cycles.

[0010] In addition, the armature section is provided with magnetic pole position detection means. The magnetic pole position detection means is arranged at three locations with the same positional intervals within a coil block in the range of one electrical angle cycle or two electrical angle cycles and in parallel with the arrangement direction of the coils. Each of the magnetic pole position detection means detects the magnetic flux density corresponding to the magnetic pole position of the field section.

[0011] When the control unit relatively moves the moving body with respect to the track section, a d-axis current target value and a q-axis current target value are set, and each of the coils of the coil block is excited by a drive voltage corresponding to the electrical angle, the d-axis current target value, and the q-axis current target value set by the electrical angle setting means.

[0012] Therefore, when the moving direction of the moving body (field section) is displaced in the arrangement direction of the coil block (a yaw angle occurs), it is also displaced with respect to the arrangement direction of the magnetic pole position detection means, and the magnetic flux density detected by each of the magnetic pole position detection means changes. This change in the magnetic flux density is a change corresponding to the inclination of the moving body and the arrangement interval of the magnetic pole position detection means.

[0013] Here, the electrical angle setting unit sets the electrical angle based on a signal indicating the magnetic flux density detected by each of the magnetic pole position detection means and the positional intervals of the magnetic pole position detection means linearly arranged along the arrangement direction of the coils. For this reason, the electrical angle setting unit can set an electrical angle that suppresses the influence of the inclination of the field section with respect to the coil block, and the control unit excites each of the coils of the coil block according to this electrical angle.

[0014] As a result, even if the moving body inclines, each coil of the coil block can be properly excited, and it is possible to suppress the occurrence of control failures or the like in the movement of the moving body. In addition, it is possible to suppress the occurrence of detuning in the moving body moving along the track section, so that the moving body can be moved in a stable state. Moreover, since it is possible to dispense with guide means for restricting the movement of the moving body in a direction intersecting the moving direction, the configuration of the track section can be simplified.

[0015] In the electromagnetic device according to the second aspect, in the first aspect, the electrical angle setting unit sets the electrical angle by correcting, based on the position interval between the magnetic pole position detection means, the electrical angle set based on a signal indicating the magnetic flux density detected by each of the magnetic pole position detection means. This is included.

[0016] In the electromagnetic device according to the third aspect, in the first or second aspect, the magnetic pole position detection means is arranged at three locations for each of the coil blocks.

[0017] In the electromagnetic device according to the fourth aspect, in the third aspect, the magnetic pole position detection means is grouped in threes, and a plurality of groups are arranged in the one direction, and the interval between the central positions of the adjacent groups in the one direction is an integral multiple of one cycle of the electrical angle. This is included.

[0018] In the electromagnetic device according to the fifth aspect, in the third or fourth aspect, the track portion includes a curved portion curved at a predetermined radius, and when the coil blocks are arranged on the curved portion in the armature portion, each of the coil blocks is arranged such that the arrangement direction of the coils is the tangential direction in the curved portion. This is included.

[0019] The electromagnetic device according to the sixth aspect, in any one of the first to fifth aspects, the field magnet part includes a first magnet block in which the permanent magnets for one electrical angle period are arranged in a first direction corresponding to the one direction, and a second magnet block in which the permanent magnets for one electrical angle period are arranged in a second direction intersecting the first direction, the first magnet block and the second magnet block are adjacent to each other in the first direction and the second direction, the first magnet blocks are diagonally adjacent to each other and the second magnet blocks are diagonally adjacent to each other, the armature part includes, as the coil block, a first coil block in which the coils for the number of phases are arranged in the one direction, and a second coil block in which the coils for the number of phases are arranged in a direction intersecting the one direction, the first coil block and the second coil block are alternately arranged in each of the one direction and the direction intersecting the one direction, the electrical angle setting part sets the electrical angle with respect to the coil block in which the coils are arranged along the moving direction of the moving body, and the control part includes exciting the coils of the coil block in which the coils are arranged along the moving direction of the moving body.

[0020] The electromagnetic device according to the seventh aspect, in any one of the first to sixth aspects, the field magnet part has the permanent magnets arranged such that the magnetization direction is changed by an angle obtained by dividing one electrical angle period by an integer of 3 or more as the number of divisions.

Advantages of the Invention

[0021] According to the electromagnetic device of the aspect of the present invention, even when the moving body is tilted, each coil of the coil block can be properly excited, and appropriate movement control of the moving body becomes possible.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [First Embodiment] In the first embodiment, a conveying device (conveying system) 10 as an electromagnetic device according to the present invention will be described as an example. In FIG. 1, a perspective view of the main part of the conveying device 10 according to the first embodiment is shown from an obliquely upper view, and in FIG. 2, the main part of the conveying device 10 is shown in a plan view from an upper view. Further, in FIG. 3(A), the main part of the conveying device 10 is shown in a front view seen from one side along the advancing direction, and in FIG. 3(B), the main part of the conveying device 10 is shown in a side view seen from one side in the width direction.

[0024] As shown in FIGS. 1 to 3, the transfer device 10 includes an orbit portion 12, a traveling portion 14 constituting a moving body, and a control portion 50 described below that controls the traveling of the traveling portion 14. A two-dimensional linear motor is configured in the transfer device 10. The operation of the orbit portion 12 of the transfer device 10 is controlled by the control portion 50, so that the traveling portion 14 is moved (advanced) along the orbit formed by the orbit portion 12. In the transfer device 10, an object to be transferred (not shown) is placed on the traveling portion 14, enabling the transfer of the object to be transferred.

[0025] In the drawings, one side in the traveling direction (moving direction) of the traveling portion 14 is indicated by an arrow Y, and one side in the device width direction, which is a direction intersecting the traveling direction, is indicated by an arrow X. The traveling portion 14 is capable of moving in the direction of the arrow Y and in the direction opposite to the direction of the arrow Y.

[0026] The orbit portion 12 includes a base 20, an armature portion 22, and an orbit plate 24 constituting a support portion. The base 20 and the orbit plate 24 are each in the shape of a strip with a required width. In the orbit portion 12, the base 20 and the orbit plate 24 face each other vertically. Further, support legs 26 having a rectangular cross-section are attached in pairs to both end portions in the width direction of the base 20 of the orbit portion 12, and the support legs 26 extend in the longitudinal direction of the base 20. In the orbit portion 12, the armature portion 22 is disposed between the pair of support legs 26.

[0027] A non-magnetic and non-conductive material is used for the orbit plate 24. The orbit plate 24 is formed of a metal material such as a stainless steel plate or a resin material such as a plastic plate, and is formed into a thin plate shape capable of supporting the traveling portion 14. Further, the orbit plate 24 is divided into left and right portions with a required width at the middle portion in the width direction of the orbit portion 12, and the divided orbit plates 24 are separately attached onto the support legs 26. As a result, in the orbit portion 12, an opening with a required width formed between the pair of orbit plates 24 extends along the base 20.

[0028] Note that, in the conveying device 10, the split track plates 24 are used for explanation. However, the track plates 24 may be made of a transparent acrylic plate or the like having light transmissivity. In this case, instead of splitting into two, one plate may be simply hung on the pair of support legs 26 for arrangement.

[0029] In the track portion 12, a strip-shaped armature base 28 is arranged between the support legs 26, and the armature base 28 extends along the longitudinal direction of the base 20. An armature portion 22 is arranged on the upper surface of the armature base 28.

[0030] For the armature portion 22, a coil block 30 having a substantially rectangular block shape is used. The armature portion 22 has a plurality of coil blocks 30 arranged on the armature base 28 and arrayed along the longitudinal direction (in the thrust generation direction) of the base 20. By arranging each of the coil blocks 30 on the armature base 28, both end portions in the width direction of each of the coil blocks 30 are close to the lower surface of the track plate 24, and the middle portion in the width direction is released upward from between the pair of track plates 24.

[0031] In the conveying device 10, three-phase alternating current power is used as the driving power for the traveling unit 14. In the armature portion 22, the coil block 30 is formed by three-phase coils (coil units) 32 (coil 32U for U phase, coil 32V for V phase, and coil 32W for W phase). The coils 32 (32U, 32V, 32W) are, for example, air-core coils made of Litz wire or the like. By using air-core (air-core coils) for the coils 32 in vector control, when the d-axis current target value is set to 0, all of the exciting currents of the coils 32 are converted into thrust, enabling efficient operation.

[0032] The coil 32 has a substantially rectangular block shape when viewed from above (it may be substantially elliptical or substantially circular), and the dimension (width dimension) Wc of the coil 32 along the width direction of the base 20 is set to a required dimension. The coil block 30 has the coils 32U, 32V, and 32W arranged in order along the longitudinal direction of the track portion 12. In the drawing, the center line Cc in the width direction of the coil block 30 (coil 32) is indicated by a dashed line.

[0033] The traveling unit 14 includes a base frame 34 as a moving body having a substantially rectangular shape when viewed from above, and a field magnet portion 36. The base frame 34 is formed by a rectangular flat bottom plate 34A and a substantially rectangular frame body (outer frame) 34B erected from the peripheral edge of the bottom plate 34A. The field magnet portion 36 is disposed on the lower surface of the bottom plate 34A of the base frame 34.

[0034] Further, a plurality of casters 38 constituting support portions are attached to the outer surface of the frame body 34B of the base frame 34, and the casters 38 are disposed so as to surround the field magnet portion 36 (at the four outer corners of the field magnet portion 36). Ball casters having balls 38A rotatably attached thereto are used as the casters 38.

[0035] In the traveling unit 14, the casters 38 of the base frame 34 correspond to each of the track plates 24, and the base frame 34 is disposed across the track plates 24 disposed opposite to the track portion 12, so that the balls 38A of the casters 38 are in contact with each of the track plates 24. Thereby, in the traveling unit 14, the upper surface of the track plate 24 is used as a track surface, and the base frame 34 is movably supported on the upper surface of the track plate 24 in a state of straddling the pair of track plates 24, and the base frame 34 functions as a vehicle that moves on the track plates 24.

[0036] In the field magnet portion 36, a plurality of permanent magnets 40 each having a substantially rectangular parallelepiped shape are used. The permanent magnet 40 has a substantially rectangular cross-section along a direction intersecting the longitudinal direction. The permanent magnet 40 has a length dimension Lm along the longitudinal direction corresponding to the width direction of the coil 32 being the same as the width dimension Wc of the coil 32 (Lm≒Wc). The longitudinal direction of the permanent magnet 40 is the width direction of the track portion 12, and a plurality of them are arranged along the track direction of the traveling portion 14 (the arrangement direction of the coil blocks 30 in the track portion 12).

[0037] In the field magnet portion 36, a field magnet for one electrical angle cycle or a plurality of electrical angle cycles is formed by the arrangement of the plurality of permanent magnets 40. A configuration (SN arrangement field magnet) in which N poles and S poles are alternately arranged downward (toward the track portion 12) may be applied to the field magnet portion 36. Further, it is preferable that a Halbach array field magnet by a Halbach magnet array is applied to the field magnet portion 36. Note that the magnetization direction of each permanent magnet 40 is a direction from the S pole toward the N pole within the permanent magnet 40, and in FIG. 3(B), the magnetization direction is indicated by an arrow within the permanent magnet 40.

[0038] In the Halbach array field magnet, with any one of integers of 3 or more as the division number m, the permanent magnets 40 whose magnetization directions are changed by an angle θm obtained by dividing one electrical angle cycle by the division number m are arranged in order. Thereby, in the Halbach array field magnet, a stronger magnetic field is formed on one side in a direction intersecting the arrangement direction of the permanent magnets 40 than on the other side. Also, in the Halbach array field magnet, the magnetic flux density along the arrangement direction (the moving direction of the traveling portion 14) of the permanent magnets 40 can be made sinusoidal, and torque ripple can be suppressed, so that the occurrence of speed unevenness or the like can be suppressed.

[0039] Further, as the Halbach array field magnet, among integers of 3 or more, a number (integer) obtained by adding 2 to a multiple of 3 may be used as the division number m. Thereby, in the Halbach array field magnet, the inclusion of harmonic components in the change of the magnetic flux density along the arrangement direction of the permanent magnets 40 can be more effectively suppressed, and torque ripple can be more effectively suppressed.

[0040] In the field magnet portion 36 of the conveying device 10, a Halbach array field magnet with a division number m of 8 (m = 8 = 3×2 + 2) and an angular θm of 45° (θm = 45° = π / 4) is applied. In the field magnet portion 36, eight permanent magnets 40 (40A to 40H) are arranged so that a strong magnetic field is generated on the lower side (the side of the track portion 12).

[0041] In the field magnet portion 36, one magnet block 46 is formed by the permanent magnets 40 (40A to 40H) for one electrical angle cycle, and the width dimension of the magnet block 46 is the length dimension Lm of the permanent magnet 40. In the field magnet portion 36, 16 permanent magnets 40 (two permanent magnets 40A to 40H each) corresponding to two electrical angle cycles are used to form two magnet blocks 46. Note that the field magnet portion 36 may be not limited to two electrical angle cycles, but may be one electrical angle cycle or three or more electrical angle cycles.

[0042] In the field magnet portion 36 to which the Halbach array field magnet is applied, in the permanent magnets 40 at both ends in the moving direction, the magnetization directions may be the same and the width dimension along the arrangement direction may be 1 / 2 of the width dimension of the other permanent magnets 40. Thereby, it is possible to suppress the occurrence of the end effect when the traveling portion 14 is moved, and it is possible to suppress the occurrence of speed unevenness or the like due to the end effect.

[0043] On the other hand, in the armature portion 22 of the track portion 12, a plurality of Hall sensors 42 as magnetic pole position detecting means and a plurality of optical sensors 44 as moving body detecting means are arranged in each of the coil blocks 30.

[0044] The Hall sensor 42 uses a Hall element, detects the strength (magnetic flux density) of a magnetic field by the Hall effect, and outputs a signal (voltage signal) corresponding to the detected magnetic flux density. In the armature unit 22, the coils 32U, 32V, and 32W are arranged at intervals of 1 / 3 of an electrical angle cycle (equidistant) with respect to a set of coil blocks 30 (for one electrical angle cycle). The Hall sensors 42U, 42V, and 42W correspond to the U-phase coil 32U, the V-phase coil 32V, and the W-phase coil 32W, respectively, and the arrangement interval of the Hall sensors 42U, 42V, and 42W is defined as the phase difference interval χ. In this case, the Hall sensors 42U, 42V, and 42W have a phase difference interval χ of 4π / 3 (interval of 240°) with respect to the field part 36 for two electrical angle cycles.

[0045] Also, the Hall sensor 42 is arranged at the center of each of the coil blocks 30. Note that the arrangement interval of the Hall sensor 42 is not limited to this, and it may be arranged at three positions (three locations) within the range of one electrical angle cycle or two electrical angle cycles corresponding to two coil blocks 30.

[0046] Also, the Hall sensors 42U, 42V, and 42W provided in one coil block 30 are regarded as a set (one sensor block). In the armature unit 22 in which a plurality of coil blocks 30 are arranged, between two adjacent sensor blocks in the arrangement direction, the interval between the center points (for example, the interval between two Hall sensors 42V) is one electrical angle cycle. Note that the interval between two adjacent coil blocks in the arrangement direction is not limited to one electrical angle cycle, and it may be a positive integer multiple of one electrical angle cycle.

[0047] The optical sensor 44 includes a light projecting unit and a light receiving unit (both not shown). The optical sensor 44 is arranged at the same pitch as the coil 32. The optical sensor 44 detects the pedestal frame 34 by detecting the light emitted from the light projecting unit and reflected by the traveling unit 14 (pedestal frame 34) at the light receiving unit. In the armature unit 22, optical sensors 44U, 44V, and 44W corresponding to the Hall sensors 42U, 42V, and 42W are used as the optical sensors 44. The optical sensors 44U, 44V, and 44W are arranged adjacent to the Hall sensors 42U, 42V, and 42W at the central portions of the coils 32, respectively. Thereby, each of the optical sensors 44 can face the pedestal frame 34 through the opening between the pair of track plates 24.

[0048] Note that the arrangement position of the optical sensor 44 is not limited to the central portion of each coil 32. The optical sensor 44 only needs to be able to detect whether the pedestal frame 34 faces at least for each coil block 30. For example, one optical sensor 44 may be arranged for each coil block 30, or one optical sensor 44 may be arranged for each between two adjacent coil blocks 30 in the moving direction of the traveling unit 14.

[0049] The transport device 10 is provided with a control unit 50. The control unit 50 controls the traveling of the traveling unit 14 by controlling the excitation of each coil 32 (32U, 32V, 32W) of the track unit 12. FIG. 4 shows a schematic configuration of the main part of the control unit 50 in a block diagram. Note that the control unit 50 functions in the same manner for each of the coil blocks 30. Hereinafter, for the sake of simplicity of explanation, the operation for mainly one coil block 30 will be described.

[0050] As shown in FIG. 4, the control unit 50 includes a traveling controller 52 and a coil excitation unit 54. The traveling controller 52 is formed with a magnetic pole position calculation unit 56 and a vector control controller 58. In addition, the control unit 50 is provided with a current sensor 48 for detecting the current (excitation current) flowing when each coil 32 (32U, 32V, 32W) is excited. The current sensor 48 detects the excitation current i of the U-phase coil 32U u , the excitation current i of the V-phase coil 32Vv and the exciting current i of the coil 32W of the W phase w Current sensors 48U, 48V, and 48W are used to detect each of them.

[0051] The traveling controller 52 includes a microcomputer (not shown) in which a CPU, a ROM, a RAM, a non-volatile storage, etc. are connected by a bus. In the traveling controller 52, the CPU reads out the magnetic pole position calculation program and the vector control program stored in the ROM and the storage and expands them in the RAM while executing them, thereby realizing the functions of the magnetic pole position calculation unit 56 and the vector control controller 58.

[0052] Each of the hall sensors 42 (42U, 42V, 42W) and the optical sensors 44 (44U, 44V, 44W) arranged in each of the coil blocks 30 in the track portion 12 is connected to the magnetic pole position calculation unit 56. In FIG. 4, for the sake of simplicity of the drawing, each of the hall sensors 42 (42U, 42V, 42W) and the optical sensors 44 (44U, 44V, 44W) is shown to be connected in a lump, but the hall sensors 42U, 42V, 42W and the optical sensors 44U, 44V, 44W are individually connected to the magnetic pole position calculation unit 56 and the like.

[0053] Each of the optical sensors 44 (44U, 44V, 44W) is connected to the coil exciting unit 54, and a three-phase AC power supply 60 is connected thereto. In addition, each of the coils 32 (32U, 32V, 32V) of the coil block 30 arranged in the track portion 12 is connected to the coil exciting unit 54.

[0054] The magnetic pole position calculation unit 56 detects the coil block 30 facing the field part 36 and the coil block 30 affected by the magnetic force of the field part 36 based on the detection signals of each of the Hall sensors 42 (42U, 42V, 42W) and the optical sensors 44 (44U, 44V, 44W) of the coil block 30. Further, the magnetic pole position calculation unit 56 calculates an electrical angle θ indicating the position (relative position) of the magnetic pole (for example, the N-pole permanent magnet 40A) of the field part 36 with respect to the coil block 30 based on the detection signal of each of the Hall sensors 42 and outputs it to the vector control controller 58.

[0055] The vector control controller 58 uses the electrical angle θ and the excitation current (current value) i of each phase detected by the current sensors 48 (48U, 48V, 48W) u 、i v 、i w to calculate voltage command values (the voltage command value v of the U-phase U * 、the voltage command value v of the V-phase V * 、and the voltage command value v of the W-phase W * ) for exciting each of the U-phase coil 32U, the V-phase coil 32V, and the W-phase coil 32W and outputs them to the coil excitation unit 54. At this time, in the vector control controller 58, a d-axis current target value and a q-axis current target value are set, and the excitation currents iu, iv, iw of each phase are controlled so as to become current values corresponding to the d-axis target current value and the q-axis current target value.

[0056] The coil excitation unit 54 uses the three-phase power supplied from the power supply 60 and performs inverter control based on the voltage command values v u * 、v v * 、v w * to supply each power of the drive voltage Vu of the U-phase, the drive voltage Vv of the V-phase, and the drive voltage Vw of the W-phase to the coils 32 (32U, 32V, 32W). As a result, in the transport device 10, each of the coils 32 (32U, 32V, 32W) of the coil block 30 is excited, and relative movement of the frame 34 of the traveling unit 14 becomes possible.

[0057] Here, while referring to the drawings, the operation of the control unit 50 in the transport device 10 will be described. In FIG. 5, the main part of the magnetic pole position calculation unit 56 is shown in a block diagram, and in FIG. 6, the main part of the vector control controller 58 is shown in a block diagram. Also, in FIG. 7, the main part of the coil excitation unit 54 is shown in a block diagram.

[0058] As shown in FIG. 5, the magnetic pole position calculation unit 56 includes a plurality of output selectors 100, a plurality of output adjusters 102, a plurality of output calculators 104, and an electrical angle calculator 106 as an electrical angle setting unit. The output selector 100 corresponds to each of the optical sensors 44 arranged in the traveling direction (arrow Y direction) of the base frame 34. Connected to the output selector 100 are the corresponding optical sensor 44, and the optical sensors 44 adjacent to the corresponding optical sensor 44 on the traveling direction side and the side opposite to the traveling direction.

[0059] For example, connected to the output selector 100 corresponding to the optical sensor 44V are the optical sensors 44U and 44W in addition to the optical sensor 44V. Also, connected to the output selector 100 corresponding to the optical sensor 44W are the optical sensors 44U and 44W, and the optical sensor 44U of the adjacent coil block 30.

[0060] The output adjuster 102 is arranged corresponding to each of the output selectors 100. The output selector 100 outputs to the corresponding output adjuster 102 whether or not each (all) of the connected optical sensors 44 has detected the base frame 34. For example, when each of the optical sensors 44U, 44V, and 44W corresponding to the optical sensor 44V has detected the base frame 34, the output selector 100 corresponding to the optical sensor 44V outputs a detection signal indicating that the base frame 34 has been detected (the base frame 34 is facing the coil block 30) to the output adjuster 102.

[0061] The output adjuster 102 is connected to Hall sensors 42 (42U, 42V, 42W) corresponding to the output selector 100. When a detection signal of the base frame 34 is input from the output selector 100, the output adjuster 102 outputs a signal (voltage) corresponding to the output signal of the Hall sensor 42. The Hall sensor 42 outputs a signal (for example, voltage) that is proportional to the magnetic flux density by the reference magnetic poles (N pole, S pole) and varies between the negative maximum value and the positive maximum value. The output adjuster 102 outputs a voltage proportional to the output signal of the Hall sensor 42. At this time, if the output signal of the Hall sensor 42 indicates zero, the output adjuster 102 outputs 0V.

[0062] The output calculators 104 are provided for each phase (output calculator 104U for the U phase, output calculator 104V for the V phase, output calculator 104W for the W phase). A plurality of output adjusters 102 of the same phase are connected to the output calculators 104U, 104V, 104W for each phase. In addition, each of the output calculators 104U, 104V, 104W is connected to the electrical angle calculator 106.

[0063] Each of the output calculators 104 (104U, 104V, 104W) outputs a voltage corresponding to the sum of the outputs of the output adjusters 102 for each phase to the electrical angle calculator 106. That is, the output adjuster 102U outputs the voltage Vha of the U phase, the output adjuster 102V outputs the voltage Vhb of the V phase, and the output adjuster 102W outputs the voltage Vhc of the W phase. Thereby, in the magnetic pole position calculation unit 56, appropriate voltages Vha, Vhb, Vhc corresponding to the magnetic flux density detected by the Hall sensors 42U, 42V, 42W can be input to the electrical angle calculator 106.

[0064] The electrical angle calculator 106 calculates the electrical angle θ based on the voltages Vha, Vhb, Vhc input from the output calculators 104U, 104V, 104W, and outputs the electrical angle θ (electrical angle signal indicating the electrical angle θ) to the vector control controller 58.

[0065] As shown in FIG. 6, the vector controller 58 includes a speed target value generator 110, a speed controller 112, a current controller 114, a voltage converter 116, a current converter 118, and an integrated electrical angle differentiator 120. The vector controller 58 also includes a d-axis current setter 122 as a setting means. The d-axis current setter 122 sets a d-axis current target value i d_ref and the d-axis current setter 122 sets, for example, a d-axis current target value i d_ref such that the d-axis current value id becomes a positive value.

[0066] The integrated electrical angle differentiator 120 calculates an electrical angular velocity ω es from the integrated electrical angle obtained by integrating the electrical angle θ input from the magnetic pole position calculation unit 56 (electrical angle calculator 106). The speed target value generator 110 generates a target value ω ref for the speed (moving speed) of the chassis frame 34 to be controlled for traveling. The speed controller 112 uses the electrical angular velocity ω es and the target value ω ref of the speed to generate a q-axis current target value i es for generating a thrust that causes the electrical angular velocity ω ref to match the target value ω q_ref in the chassis frame 34.

[0067] The current converter 118 is connected to current sensors 48U, 48V, and 48W, and the electrical angle θ is input thereto. The current converter 152 converts the excitation currents (current values) iu, iv, and iw of the U-phase, V-phase, and W-phase input from the current sensor 48 based on the electrical angle θ and outputs a d-axis current (current value) id and a q-axis current (current value) iq.

[0068] The current controller 114 is based on the q-axis current target value i q_ref , the d-axis current target value i d_ref , the d-axis current id, and the q-axis current iq, and the d-axis current id and the q-axis current iq are respectively set to the d-axis current target value i d_ref and the q-axis current target value i q_ref to generate a d-axis voltage command value v d * and a q-axis voltage command value v q* Perform calculations and output.

[0069] The voltage converter 116 receives the electrical angle θ, the d-axis voltage command value v d * , and the q-axis voltage command value v q * . The voltage converter 116 performs voltage conversion based on the electrical angle θ to convert the d-axis voltage command value v d * and the q-axis voltage command value v q * into the voltage command values of each phase (the voltage command value v u * of the U phase, the voltage command value v v * of the V phase, and the voltage command value v w * ) of the W phase, and outputs them to the coil excitation unit 54.

[0070] As shown in FIG. 7, the coil excitation unit 54 includes a plurality of excitation selectors 130 and a plurality of excitation devices 132. The excitation selectors 130 and the excitation devices 132 are provided for each coil 32 (32U, 32V, 32W) of the coil block 30. A photosensor 44 corresponding to the coil 32 is connected to the excitation selector 130. For example, a photosensor 44U corresponding to the coil 32U and a photosensor 44V (or photosensors 44V, 44W) adjacent to the advancing direction side of the photosensor 44U are connected to the excitation selector 130.

[0071] When at least one of the connected photosensors 44 detects the base frame 34, the excitation selector 130 outputs a detection signal indicating that the base frame 34 is detected to the corresponding excitation device 132.

[0072] When a detection signal is input from the corresponding excitation selector 130, the excitation devices 132 (132U, 132V, 132W) receive the voltage command values v U * , v V * , v W *The drive voltage (excitation voltage) V that matches u , V v , V w is output to each of the coils 32U, 32V, and 32W. As a result, the coils 32U, 32V, and 32W of each phase are excited, and the frame 34 is moved at a speed corresponding to the target value ω ref .

[0073] Note that when a signal indicating that the excitation device 132 has not detected the frame 34 is input from the excitation selector 130, the excitation of the coil 32 of the corresponding phase is stopped. As a result, the control unit 50 can excite only the coil 32 near the frame 34, and can suppress the power consumption for exciting the coil 32.

[0074] In the transport device 10 configured as described above, in the armature part 22, a coil block 30 formed by arranging three-phase coils 32U, 32V, and 32W along one direction is further arranged along one direction. Also, in the traveling part 14, permanent magnets 40 are arranged to form a field part 36. Therefore, by opposing the armature part 22 and the field part 36 so that the arrangement direction of the coil 32 and the arrangement direction of the permanent magnet 40 overlap, a propulsive force is generated in the frame 34 in the direction along the arrangement direction of the coil 32.

[0075] In the vector control controller 58, the electrical angle θ calculated from the detection signals of the hall sensors 42 (42U, 42V, 42W), and the d-axis current id and q-axis current iq are obtained from the excitation currents iu, iv, iw of each phase, and the d-axis current id and q-axis current iq are respectively the d-axis current target value i d_ref and the q-axis current target value i q_ref such that the d-axis voltage command value v d * and the q-axis voltage command value v q * are calculated, and the drive voltages Vu, Vv, Vw for exciting the coils 32 of each phase are output.

[0076] In the transfer device 10, when the coils 32U, 32V, and 32W are excited by the drive voltages Vu, Vv, and Vw, the coils 32U, 32V, and 32W generate a moving magnetic field, and a propulsive force is applied to the field magnet portion 36 by this moving magnetic field to move the base frame 34. At this time, the speed target value ω ref is set by the speed target value generator 110, and from this target value ω ref the q-axis current target value i q_ref is set, so that the base frame 34 is moved at a speed corresponding to the target value ω ref .

[0077] Incidentally, the Hall sensors 42 provided in the coil block 30 of the track portion 12 are linearly arranged in parallel with the arrangement direction of the coils 32 in the coil block 30. As a result, when the base frame 34 is moved without being tilted with respect to the moving direction, each of the Hall sensors 42 can output an appropriate detection signal according to the magnetic flux density of the field magnet portion 36.

[0078] However, if a tilt (yaw angle) occurs in the traveling direction of the base frame 34 with respect to the arrangement direction of the coils 32 in the coil block 30, the detection signals of the Hall sensors 42 also change. As a result, it may be difficult to detect the appropriate electrical angle θ and perform appropriate vector control.

[0079] An electrical angle calculator 106 is provided in the magnetic pole position calculation unit 56 of the traveling controller 52 in the control unit 50. The electrical angle calculator 106 sets the electrical angle θ from the voltages Vha, Vhb, and Vhc according to the detection results of the Hall sensors 42U, 42V, and 42W. The electrical angle θ is information indicating the position of the N pole of the field magnet portion 36 with respect to the coil block 30. If the moving distance of the N pole is dm and the pole pitch (pole pitch) is τ, the electrical angle θ is θ = (π / τ)·dm. Therefore, since the Hall sensors 42 are arranged at preset intervals, the electrical angle θ can be obtained from the output of the Hall sensors 42.

[0080] As shown in FIG. 5, each of the voltages Vha, Vhb, and Vhc is input to the electrical angle calculator 106 from the U-phase output calculator 104U, the V-phase output calculator 104V, and the W-phase output calculator 104W. The electrical angle calculator 106 sets the electrical angle θ based on the voltages Vha, Vhb, and Vhc. FIG. 8 shows a schematic configuration of the electrical angle calculator 106 for calculating the electrical angle θ in a block diagram.

[0081] As shown in FIG. 8, the electrical angle calculator 106 includes an amplifier 140, an absolute value calculator 142, a multiplier 144, an adder 146, an absolute value calculator 148, an adder 150, an integrator 152, and an amplifier 154.

[0082] Also, the electrical angle calculator 106 includes a multiplier 156, a sine calculator 158, an amplifier 160, a constant generator 162, a subtractor 164, a multiplier 166, an adder 168, and an amplifier 170. Further, the electrical angle calculator 106 includes an arctangent calculator 172, an amplifier 174, a sine calculator 176, a divider 178, an arctangent calculator 180, a ratio calculator 182, a constant generator 184, and a divider 186.

[0083] In the electrical angle calculator 106, the voltages Vha, Vhb, and Vhc are input. When the voltage Vhb is input to the amplifier 140, the input voltage Vhb is amplified by a factor of 2 and output to the absolute value calculator 142. The absolute value calculator 142 takes the absolute value from the output of the adder 140 and outputs it to the multiplier 144. Also, when the voltages Vha and Vhc are input to the adder 146, the sum of the voltages Vha and Vhc is taken and output to the absolute value calculator 148. The absolute value calculator 148 takes the absolute value from the output of the adder 146 and outputs it to the adder 150.

[0084] The adder 150 adds the output of the absolute value calculator 148 and the output of the multiplier 144 and outputs the sum to the integrator 152. The integrator 152 time-integrates the input signal of the adder 150 and outputs it to the amplifier 154. The amplifier 154 amplifies the output of the integrator 152 by multiplying it by a predetermined gain G and outputs it to the multiplier 144. The multiplier 144 multiplies the output of the amplifier 154 and the output of the absolute value calculation unit 142 and outputs the result to the adder 150.

[0085] The adder 150 adds the output of the absolute value calculator 148 and the output of the multiplier 144 and outputs the sum to the integrator 152. As a result, in the electrical angle calculator 106, a loop of adder 150 - integrator 152 - amplifier 154 - multiplier 144 - adder 150 is formed for the input voltages Vha, Vhb, and Vhc.

[0086] On the other hand, the output of the amplifier 154 is input to the multiplier 156 and the sine calculator 158. The multiplier 156 outputs the square of the output of the amplifier 154 to the amplifier 160. The amplifier 160 outputs twice the output of the multiplier 156 to the subtractor 164. Also, the constant generator 162 outputs the output value 1 to the subtractor 164. As a result, the subtractor 164 subtracts the output of the amplifier 160 from the output value 1 of the constant generator 162 and outputs the result to the multiplier 166.

[0087] The multiplier 166 multiplies the output of the subtractor 160 and the voltage ha and outputs the result to the adder 168. The adder 168 adds the output of the multiplier 166 and the voltage Vhc and outputs the result to the divider 178.

[0088] Also, the sine wave calculator 158 calculates the sine (sin) of the output of the amplifier 154 and outputs it to the amplifier 170. The amplifier 170 multiplies the output gain value H of the sine wave calculator 158 and outputs it to the arctangent calculator 172. In the arctangent calculator 172, the ratio of the output of the amplifier 170 to the output of the amplifier 154 is calculated, and the arctangent of the calculation result is calculated.

[0089] Furthermore, the calculation result of the arctangent calculator 172 is output to the amplifier 174 and the ratio calculator 182. The amplifier 174 multiplies the output of the arctangent calculator 172 by 2 and outputs it to the sine calculator 176. The sine calculator 176 calculates the sine of the output of the amplifier 174 and outputs it to the divider 178. In the divider 178, the output of the adder 168 is divided by the output of the sine calculator 176 and output to the arctangent calculator 180. In the arctangent calculator 180, the ratio of the output of the divider 178 to the voltage Vha is obtained and output to the divider 186.

[0090] Also, the constant generator 184 outputs the phase difference interval χ, which is the mounting phase difference of the Hall sensors 42U, 42V, and 42W, to the ratio calculator 182. The ratio calculator 182 calculates the ratio of the output value (α) of the arctangent calculator 172 to the phase difference interval χ when the output value of the arctangent calculator 172 is input. Thereby, the equation (13) is executed, and the electrical angle θ is output from the electrical angle calculator 106.

[0091] The output electrical angle θ is the electrical angle θ from which the influence of the yaw angle δ has been removed (not received) from the voltages Vha, Vhb, and Vhc corresponding to the detection results of the Hall sensors 42U, 42V, and 42W, and the electrical angle calculator 106 can output an appropriate electrical angle θ.

[0092] In the carrier device 10 configured as described above, the base frame 34 moves on the track plate 24 of the track portion 12. At this time, for example, when the base frame 34 contacts or steps on a foreign object on the track plate 24, the traveling direction (center line Cm) of the base frame 34 may tilt with respect to the armature portion 22 (center line Cc), and a yaw angle δ may occur.

[0093] In the electrical angle calculator 106 of the control unit 50, when calculating the electrical angle θ based on the detection result of the Hall sensor 42, the electrical angle θ from which the influence of the yaw angle δ has been removed is calculated. Also, in the control unit 50, each of the coils 32 is excited using the electrical angle θ from which the influence of the yaw angle δ has been removed. Thereby, in the carrier device 10, even when the yaw angle δ occurs, the excitation of the coil 32 can be properly controlled, and the movement of the base frame 34 can be properly controlled.

[0094] Next, the calculation process of the electrical angle θ in the electrical angle calculator 106 will be described. In FIGS. 9(A) and 9(B), the schematic configuration of the main part of the transfer device 10 is shown in a plan view. Note that FIG. 9(A) shows a state where the base frame 34 is along the arrangement of the coil blocks 30, and FIG. 9(B) shows a state where the base frame 34 is inclined with respect to the arrangement direction of the coil blocks 30.

[0095] In the transfer device 10, the length of the coil 32 in the coil block 30 in the arrangement direction is twice the length along the arrangement direction of the permanent magnets 40 of the magnet block 46 corresponding to one cycle of the electrical angle. In the magnet block 46, a Halbach array magnetic field in which the magnetic flux density changes in a sine wave shape is formed. By making the length of the coil block 30 corresponding to one cycle of the electrical angle an integer multiple of the length of the magnet block 46, the thrust ripple when the magnet block 46 moves can be reduced. For this reason, in the transfer device 10, the thrust ripple when the base frame 34 moves can be reduced.

[0096] In the armature part 22, Hall sensors 42 are arranged at intervals of 1 / 3 of one cycle of the electrical angle (2 / 3π) with respect to the coil block 30 corresponding to one cycle of the electrical angle. Also, in each coil block 30, the arrangement direction of the Hall sensors 42 is parallel to the arrangement direction of the coils 32 in the coil block 30.

[0097] The electrical angle calculation unit 106 calculates the electrical angle θ as position information indicating the relative position of the N pole (permanent magnet 40A) with respect to the coil block 30 based on the detection signals of the Hall sensors 42 (42U, 42V, 42W) corresponding to the change in the magnetic flux density generated by the magnet block 46.

[0098] For the detection of the general electrical angle θ, Hall sensors arranged at intervals of π / 2 (90°) with respect to the period of the coil array are used. When measuring the sinusoidal magnetic flux density distribution in the Halbach array magnetic field using this Hall sensor, taking the electrical angle θ when the N pole is located directly above the U-phase coil as the origin (θ = 0), the outputs of two Hall sensors A and B (not shown in the figure) are defined as voltages Va and Vb. In this case, the electrical angle θ is expressed by Equation (1).

[0099] θ = arctan(Vb / Va) (1)

[0100] At this time, the Hall sensor A that outputs the voltage Va does not necessarily need to be arranged at the center of the U-phase coil. If the electrical angle offset value from the center of the U-phase coil to the mounting position of the Hall sensor A is known, by considering this electrical angle offset value, the electrical angle θ can be obtained using Equation (1).

[0101] As shown in FIGS. 9(A) and 9(B), in the conveying device 10 (armature part 22), the arrangement interval (phase difference interval χ) of the Hall sensors 42 is set to an electrical angle of 120° (χ = 2π / 3). When the phase difference interval χ of the Hall sensors 42 is set to an electrical angle of 120° or an electrical angle of 240° (χ = 4π / 3), by performing a rotational coordinate transformation on the voltages output by the Hall sensors 42, the electrical angle θ of the magnetic pole position (for example, the N pole position) can be obtained.

[0102] Here, in the conveying device 10, the output signals of the Hall sensors 42U, 42V, and 42W are defined as voltages Vha, Vhb, and Vhc, respectively. In this case, applying the αβ coordinate system as the rotational coordinate system, with the α-axis voltage being Vα and the β-axis voltage being Vβ, the electrical angle θ is as follows from Equation (1).

[0103] θ = arctan(Vβ / Vα)

[0104] Note that the αβ conversion is based on Equation (2).

[0105]

Equation

[0106] When the phase difference interval χ of the Hall sensor 42 is 240°, the value obtained by multiplying the electrical angle θ obtained from the formula (2) by "-1" becomes the electrical angle θ to be obtained.

[0107] When using three Hall sensors 42 (42U, 42V, 42W), one Hall sensor 42 may be arranged in one coil 32, and since the coil 32 incorporating the Hall sensor 42 can be used, mass production becomes easy. In addition, if the sum of the outputs of the Hall sensors 42 of the coils 32 of each phase is taken and the tangent (arctangent) is calculated from the voltages Vα and Vβ obtained by performing αβ conversion, there is also an advantage that the electrical angle θ can be calculated regardless of where the field part 36 is on the coil 32 array (on the coil block 30).

[0108] On the other hand, as shown in FIG. 9(B), when an inclination occurs in the traveling direction (direction along the center line Cm) of the base frame 34 with respect to the array direction (direction along the center line Cc) of the coil block 30 (coil 32), the center line Cc and the center line Cm intersect, and a yaw angle δ occurs between the center line Cc and the center line Cm. When the traveling direction coincides with the array direction, the yaw angle δ = 0°.

[0109] The voltages Vha, Vhb, and Vhc output from each of the Hall sensors 42U, 42V, and 42W when the yaw angle δ occurs can be expressed by the formula (3) with respect to the electrical angle θ before the yaw angle δ occurs.

[0110]

Equation

[0111] At this time, for simplification, when θcosδ is replaced with η (η = θcosδ) and χcosδ is replaced with α (α = χcosδ), the formula (3) becomes the formula (4).

[0112]

Equation

[0113] Here, by modifying equation (4), equation (5) is obtained. Furthermore, since Vha=cos(η) in equation (4), equation (6) can be obtained from equation (5).

[0114]

number

[0115] Furthermore, since the voltage Vha detected by the Hall sensor 42A is a signal that crosses zero, cosα is replaced with the error Er (Er=cosα), thereby obtaining equation (7).

[0116]

number

[0117] In this case, G is the gain, and by setting the gain G to a predetermined value, the error Er converges to cos α over time.

[0118] On the other hand, the voltage Vhc in equation (4) is expressed by equation (8), which can be transformed into equation (9).

[0119]

number

[0120] Furthermore, from the phase difference interval χ of the Hall sensor 42, α=χcosδ. For this reason, if cosδ does not take the value of α=(N / 2)π (where N is an integer), it is possible to divide both sides of equation (8) by sin2α. Also, α can be calculated using arccos (the inverse function of cosine) of the value of cosα obtained from the calculation of equation (7), but since the value range of α is [0,π) (0≦α<π) and α cannot be detected directly, sinα is used as equation (10).

[0121]

Mathematics

[0122] In equation (10), when the phase difference interval χ satisfies χ > π, a negative sign (-) is adopted for the sign, and the range of the yaw angle δ that satisfies the above conditions is limited. Then, α must be calculated from cosα and sinα by inverse tangent (arctangent). If α can be calculated, the magnitude of the yaw angle δ can be determined by equation (11).

[0123]

Mathematics

[0124] Furthermore, if cosδ does not take the value of α = (N / 2)π (where N is an integer), sinη can be calculated by equation (12) from equation (8).

[0125]

Mathematics

[0126] Here, since η = θcosδ and Vha = cosη, θ becomes equation (13) from equation (12).

[0127]

Mathematics

[0128] Therefore, equation (13) holds even when the yaw angle δ = 0. If the yaw angle δ satisfies (-π / 2) < δ < (π / 2), even when a yaw angle δ occurs in the frame 34 where the field pole part 36 is arranged, the electrical angle θ, which is information indicating the original magnetic pole position of the frame 34 where the field pole part 36 is arranged, can be measured from the outputs of the hall sensors 42 (42U, 42V, 42W) arranged at the same phase difference interval χ.

[0129] For example, when corresponding to the case where the yaw angle δ changes within the value range [0, π / 2) (0 ≤ δ < (π / 2)), if the phase difference interval χ of the Hall sensor 42 is χ < (π / 2), sin2α will not become 0 (sin2α ≠ 0). Also, due to the convenience of mounting the Hall sensor 42 or the like, when the phase difference interval χ becomes χ = 2π / 3 or χ = 4π / 3, the electrical angle θ can be measured within the range of the yaw angle δ that satisfies (3 / 4) < cosδ ≤ 1. That is, when the yaw angle δ satisfies cosδ = (4 / 3), α = π / 2, and a so-called division by zero occurs in equation (12), so cosδ = (4 / 3) is not included.

[0130] On the other hand, in the electrical angle calculator 106 shown in FIG. 8, the processing corresponding to equations (5) to (13) is executed. That is, in the electrical angle calculator 106, a loop is formed from the input voltages Vha, Vhb, and Vhc to the adder 150 - integrator 152 - amplifier 154 - multiplier 144 - and back to the adder 150.

[0131] As a result, in the electrical angle calculator 106, the differential equations of equations (6) and (7) are integrated, and the output of the amplifier 154 converges to the cosine value (cosα) of α (α = χcosδ) which is the value obtained by multiplying the phase difference interval χ of the Hall sensor 42 by the cosine of the yaw angle δ (cosδ). At this time, the value of the gain G of the amplifier 154 may be appropriately determined so that the required convergence speed can be obtained.

[0132] Also, in the electrical angle calculator 106, the cosine value (cosα) output from the amplifier 154 is squared in the multiplier 156, doubled in the amplifier 160, and then subtracted from the output value 1 in the subtractor 164. Also, in the sine calculator 158, the sine value (sinα) of α is output from the cosine value (cosα) of α output from the amplifier 154, and this output is multiplied by the gain value H by the amplifier 170 and output to the arctangent calculator 172. At this time, the gain value H of the amplifier 170 is set to "1" if the phase difference interval χ of the Hall sensor 42 is less than π (0 < χ < π), and "-1" if it is greater than the phase difference interval χ (χ > π).

[0133] The inverse tangent calculator 172 receives the output of the amplifier 154 and the output of the amplifier 170. The inverse tangent calculator 172 calculates the ratio of the output value of the amplifier 170 to the output value of the amplifier 154, and calculates the arctangent of the calculation result. Thereby, the inverse tangent calculator 172 outputs α, which is the value obtained by multiplying the phase interval χ of the hall sensor 42 by the cosine (cosδ) of the yaw angle δ of the base frame 34.

[0134] The amplifier 174 multiplies the output (α) of the inverse tangent calculator 172 by 2 and outputs it to the sine calculator 176. The sine calculator 176 calculates the sine value of the output of the amplifier 174 and outputs it to the divider 178. Also, the multiplier 166 multiplies the output of the subtractor 164 and the voltage Vhc and outputs (multiplies) it to the adder 168. The adder 168 adds the output of the multiplier 166 and the voltage Vha and outputs it to the divider 178.

[0135] The divider 178 divides the output of the adder 168 by the output of the sine calculator 176. Thereby, the equation (12) is executed and sinη is output. The divider 178 outputs the division result (sinη) to the inverse tangent calculator 180. In the inverse tangent calculator 180, the ratio of the output (sinη) of the divider 178 to the voltage Vha is calculated, and the arctangent of the calculation result is calculated. Thereby, the inverse tangent calculator 180 outputs η (η = θcosδ), which is the value obtained by multiplying the electrical angle θ indicating the proper magnetic pole position of the field portion 36 to which the Halbach array field is applied by the cosine of the yaw angle δ.

[0136] Therefore, even when a yaw angle δ occurs in the base frame 34, the electrical angle calculator 106 can obtain the proper electrical angle θ. For this reason, the control unit 50 can accurately perform the running control of the base frame 34.

[0137] Also, in the control unit 50, the d-axis current target value i d_refBy setting it to a positive value, the electromagnetic force generated between the coil block 30 and the magnet block 46 becomes an attractive force. As a result, a force acts on the magnet block 46 in a direction that overlaps the center line Cm with the center line Cc of the coil block 30, so that the yaw angle δ can be set to δ = 0, and the inclination of the base frame 34 can be eliminated.

[0138] On the other hand, in the transport device 10, a curved portion 12A can also be formed in the track portion 12. FIG. 10 shows a schematic configuration of a main portion of the track portion 12 including the curved portion 12A in a plan view.

[0139] As shown in FIG. 10, in the track portion 12, the curved portion 12A is connected between the straight portions 12B. In the curved portion 12A, the center line Cc is formed in an arc shape with a predetermined radius (curvature radius) R, and straight portions 12B are connected to each of both ends of the curved portion 12A. Thereby, the base frame 34 is made movable from one straight portion 12B through the curved portion 12A to the other straight portion 12B.

[0140] In the curved portion 12A, a plurality of coil blocks 30 are arranged along the center line Cc. In each of the coil blocks 30, the arrangement direction of the coils 32 is the tangential direction of the center line Cc.

[0141] Also, a Hall sensor 42 (42U, 42V, 42W) is arranged in each of the coil blocks 30. The Hall sensors 42U, 42V, 42W have a phase difference interval χ of χ = (2π / 3) and are arranged in parallel with the arrangement direction of the coils 32 in each coil block 30.

[0142] In the track portion 12 configured as described above, the base frame 34 is moved through the curved portion 12A in a state where a predetermined yaw angle δ is generated with respect to the arrangement direction of the coils 32 in each coil block 30.

[0143] Here, in the control unit 50, the electrical angle calculation unit 106 calculates the electrical angle θ based on the voltages Vha, Vhb, and Vhc obtained from the detection results of the Hall sensors 42U, 42V, and 42W in each of the coil blocks 30. At this time, the electrical angle calculation unit 106 calculates the electrical angle θ excluding the influence of the yaw angle δ.

[0144] As a result, when the base frame 34 moves along the curved portion 12A, the control unit 50 can excite the coils 32U, 32V, and 32W based on the electrical angle θ from which the influence of the yaw angle δ has been removed in each of the coil blocks 30.

[0145] Therefore, in the conveying device 10, even when the base frame 34 moves along the curved portion 12A, each coil 32 can be properly excited, preventing movement obstacles such as out-of-tune from occurring in the base frame 34, and allowing the base frame 34 to move smoothly along the curved portion 12A.

[0146] Note that in the curved portion 12A, the coil blocks 30 are arranged along the center line Cc. However, the centers of the plurality of coils 32U, 32V, and 32W may be arranged on the center line. That is, the centers of the plurality of coils 32U, 32V, and 32W may be aligned with the center line Cc of the curved portion 12A, and the width directions of each may be directed toward the center of curvature of the curved portion 12A, such that the continuous coils 32U, 32V, and 32W form one coil block.

[0147] In this case, for example, the Hall sensors 42U, 42V, and 42V may be arranged on the tangent line of the center line Cc passing through the center of the coil 32V in each coil block. Also, the coil blocks at the circumferential end portions in the curved portion 12A may include the coils 32 on the curved portion 12A side of the straight portion 12B.

[0148] In the first embodiment, the base frame 34 was detected by the optical sensor 44. However, a Hall sensor 42 may be used as the moving body detection means for detecting the base frame 34. The Hall sensor 42 detects the magnetic flux density by the permanent magnet 40 of the magnetic field portion 36 disposed on the base frame 34. By detecting the magnetic flux density using the Hall sensor 42, it is possible to detect whether the base frame 34 is facing the corresponding coil block 30 (or coil 32), whether the base frame 34 is approaching, or whether the base frame 34 is away. As described above, if, for example, a transparent acrylic plate or the like is used as the track plate 24, the base frame 34 can be detected without dividing the track plate 24.

[0149] When the Hall sensor 42 is used as the moving body detection means, in the magnetic pole position calculation unit 56, the Hall sensor 42 is connected to each of the output selectors 100, and the base frame 34 may be detected from the magnetic flux density detected by each of the Hall sensors 42 in the output selector 100. Further, in the coil excitation unit 54, the Hall sensor 42 is connected to each of the excitation selectors 130, and the base frame 34 may be detected from the magnetic flux density detected by each of the Hall sensors 42 in the excitation selector 130. Further, when the Hall sensor 42 is used, it is not necessary to divide the track plate 24, and the configuration of the track surface formed by the track plate 24 can be simplified.

[0150] Also, in the first embodiment, the caster 38 that freely moves on the track plate 24 is used as the support portion. However, various configurations can be applied as long as the support portion is configured to support the moving body movably in the track portion. For example, as the support portion, a bottom plate provided on the moving body side and an upper plate with which the bottom plate is in sliding contact on the track portion side may be applied. In this case, for the bottom plate and the upper plate, a combination in which each is made of a non-magnetic and non-conductive material and has low friction between them may be applied.

[0151] 〔Second Embodiment〕 Next, a second embodiment of the present invention will be described with reference to FIGS. 11 and 12. In the second embodiment, the same components and the same configurations as those in the first embodiment are given the same reference numerals as those in the first embodiment, and the description thereof is omitted.

[0152] FIG. 11 shows a main part of the transport device 70 according to the second embodiment in a plan view. As shown in FIG. 11, the transport device 70 includes an orbital part 72 and a traveling part 74. FIG. 12(A) shows an arrangement of the coil blocks 30 formed in the orbital part 72 in a plan view, and FIG. 12(B) shows a main part of the traveling part 74 in a plan view.

[0153] As shown in FIG. 11, the orbital part 72 includes an armature part 76 and an orbital plate (not shown). The armature part 76 and the orbital plate are applied to the second embodiment instead of the armature part 22 and the orbital plate 24 of the first embodiment, respectively.

[0154] A non-magnetic and non-conductive material can be used for the orbital plate, and the orbital plate can be made of a metal material such as a stainless steel plate or a resin material such as a plastic plate. In the second embodiment, the orbital plate is formed into a substantially rectangular thin plate shape capable of supporting the traveling part 74, and an acrylic plate having light transmissivity is used. Therefore, the orbital plate forms an orbital surface that covers the armature part 76 in a state where the moving body on the upper surface can be detected by the optical sensor 44.

[0155] The armature part 76 is provided with coil blocks 30. As also shown in FIG. 12(A), the coil blocks 30 include a coil block 30A in which the coils 32U, 32V, and 32W are arranged in one direction and a coil block 30B in which the coils 32U, 32V, and 32W are arranged in a direction intersecting the one direction.

[0156] In the armature part 76 provided in the orbital part 72, the coil block 30A and the coil block 30B are alternately arranged in each of the one direction and the direction intersecting the one direction. As a result, in the armature part 76, the coil blocks 30 (30A, 30B) are arranged so as to form a checkered pattern, and the center lines Cc of the coil blocks 30 (30A, 30B) are formed in a lattice shape.

[0157] Each of the coil blocks 30A and 30B is provided with a Hall sensor 42. The Hall sensors 42U, 42V, and 42W may be linearly arranged at the same phase difference interval χ within a range of one or two electrical angle cycles. Also, the Hall sensors 42U, 42V, and 42W may be located at positions where they can detect the magnetic flux density from the magnet block 46 of the following pedestal frame 80 where electromagnetic force is generated.

[0158] From here, in the coil blocks 30A and 30B, the Hall sensor 42 (42U, 42V, 42W) is arranged in the central coil 32V, and an optical sensor 44 is arranged adjacent to each of the Hall sensors 42. Note that the optical sensor 44 is omitted in the drawing. The optical sensor 44 is not limited to this and may be arranged in each of the coils 32U, 32V, and 32W.

[0159] Also, in the coil blocks 30A and 30B, the phase difference interval χ of the Hall sensors 42U, 42V, and 42W is set to 2π / 3 (χ = 2π / 3 = 120°) (one coil 32 corresponds to 240° in electrical angle). That is, the Hall sensor 42V is arranged at the center of the coil 32V, the Hall sensor 42U is arranged between the coil 32U and the coil 32V, and the Hall sensor 42W is arranged between the coil 32V and the coil 32W. Also, the Hall sensors 42U, 42V, and 42W are linearly arranged along the arrangement direction of the coil 32. Thereby, for example, the Hall sensors 42U, 42V, and 42W may be arranged in the coil 32V without arranging the Hall sensor 42 in the coils 32U and 32W. Thereby, the manufacturing of the coil blocks 30A and 30B becomes easier compared to the case where the Hall sensor 42 is provided in each of the coils 32U, 32V, and 32W.

[0160] As shown in FIG. 12(B), a pedestal frame 80 is used for the traveling unit 74, and a field magnet portion 82 is arranged in the pedestal frame 80. The pedestal frame 80 and the field magnet portion 82 are applied to the second embodiment instead of the pedestal frame 34 and the field magnet portion 36 of the first embodiment.

[0161] The base frame 80 uses a frame body 84 that is rectangular when viewed from above, and casters 38 (not shown in the second embodiment) are attached to required positions of the frame body 84. As a result, when the base frame 80 is placed on the track slab, the traveling unit 74 can freely move on the upper surface (track surface) of the track slab via the casters 38.

[0162] The field magnet portion 82 is disposed on the bottom surface of the frame body 84, and a plurality of magnet blocks 46 are used for the field magnet portion 82. The magnet blocks 46 include a magnet block 46A in which the arrangement direction of the permanent magnets 40 is the first direction, and a magnet block 46B in which the arrangement direction of the permanent magnets 40 is the second direction that intersects the first direction. In the field magnet portion 82, one of the magnet blocks 46A and 46B is the first magnet block, and the other is the second magnet block.

[0163] In the field magnet portion 82, the magnet block 46A and the magnet block 46B are adjacent in the first direction and the second direction, and the magnet blocks 46A are adjacent to each other diagonally, and the magnet blocks 46B are adjacent to each other diagonally. Also, the magnet blocks 46A and 46B have a size (area) corresponding to each coil block 30. Further, in the base frame 80, the center line Cd is formed along the second direction and the first direction at the center positions of the first direction and the second direction, respectively.

[0164] As a result, as shown in FIG. 11, the magnet blocks 46A and 46B can each correspond to one of the coil blocks 30A and 30B. Note that the magnet blocks 46A and 46B of the field magnet portion 82 may have a size such that they can face the coil blocks 30A and 30B in which two of each are arranged vertically and horizontally. Also, in FIG. 11, the base frame 80 is in a state where a yaw angle δ has occurred.

[0165] In the control unit 50 of the transfer device 70, each coil 32 of the coil blocks 30A and 30B where the base frame 80 is detected can be excited. At this time, the control unit 50 selectively moves the base frame 80 in the direction along the arrow Y direction and the direction along the arrow X direction by exciting the coil 32 of the coil block 30A or the coil block 30B according to the moving direction of the base frame 80.

[0166] When the control unit 50 moves the base frame 80 in the arrow Y direction, each of the coils 32 (32U, 32V, 32W) of the coil block 30A is excited. As a result, in the traveling unit 74, a propulsive force is generated in each of the magnet blocks 46A arranged obliquely. Further, when the control unit 50 moves the base frame 80 in the arrow X direction, each of the coils 32 (32U, 32V, 32W) of the coil block 30B is excited. As a result, in the traveling unit 74, a propulsive force is generated in each of the magnet blocks 46B arranged obliquely.

[0167] At this time, the magnet blocks 46A are arranged obliquely with respect to each other and the magnet blocks 46B are arranged obliquely with respect to each other on the base frame 80. For this reason, in the base frame 80, the same thrust (the same direction and magnitude of the thrust) is generated in the magnet block 46A, so that it is moved in the arrow Y direction, and the same thrust is generated in the magnet block 46B, so that it is moved in the arrow X direction. As a result, the base frame 34 is moved so that the center line Cd is formed in a lattice shape in the track portion 72 and along any of the center lines Cc.

[0168] In the transfer device 70 configured as described above, the control unit 50 sets the d-axis current target value i d_ref , and the q-axis current target value i q_ref for the coil block 30A or 30B where the base frame 80 is detected by the optical sensor 44, and according to the electrical angle θ, the d-axis current target value i d_ref , and the q-axis current target value i q_ref , and the exciting currents iu, iv, id are set so that the coil 32U, 32V, 32W are excited to have current values corresponding to the d-axis current target value i d_ref and the q-axis current target value i q_ref .

[0169] As a result, in the transport device 70, the base frame 80 is moved along the center line Cc in the direction of arrow Y or the direction of arrow X.

[0170] On the other hand, the control unit 50 is provided with an electrical angle calculation unit 106, and the electrical angle calculation unit 106 sets an electrical angle θ from which the influence of the yaw angle δ is removed according to the voltages Vha, Vhb, and Vhc detected by the Hall sensors 42U, 42V, and 42W.

[0171] For example, when the base frame 80 contacts a foreign object or the like on the track slab, the center line Cd may tilt with respect to the center line Cc and a yaw angle δ may occur. When the yaw angle δ occurs in the base frame 80, the voltages Vha, Vhb, and Vhc detected by the Hall sensors 42U, 42V, and 42W are affected by the yaw angle δ.

[0172] The electrical angle calculation unit 106 sets the electrical angle θ according to the voltages Vha, Vhb, Vhc detected by the Hall sensors 42U, 42V, 42W, and the phase difference interval χ between the Hall sensors 42U, 42V, 42W. In the control unit 50, based on the electrical angle θ set in the electrical angle calculation unit 106, the drive voltages Vu, Vv, Vw of the respective coils 32U, 32V, 32W are set.

[0173] As a result, in the transport device 70, the same effects as those of the transport device 10 of the first embodiment can be achieved.

[0174] Also, in the transport device 70, even when a yaw angle δ occurs in the base frame 80, the coils 32U, 32V, 32W of the coil block 30 are excited according to the electrical angle from which the influence of the yaw angle δ is removed. Therefore, in the transport device 70, regardless of whether the yaw angle δ occurs, the respective coils 32U, 32V, 32W are properly excited and the base frame 80 is properly moved.

[0175] Furthermore, in the transport device 70, since guide means such as a guide for restricting movement in a direction intersecting the moving direction of the base frame 80 becomes unnecessary, the configuration of the track portion 72 can be simplified and the base frame 80 can be moved to an arbitrary position on the track slab.

[0176] In the first and second embodiments described above, three-phase power is used as the power source for exciting the coil 32. However, the power source is not limited to three-phase power and may be two-phase power or power of four or more phases. Even in these cases, one coil block may be formed by arranging coils corresponding to the number of phases.

Explanation of Reference Numerals

[0177] 10, 70 Conveying device 12, 72 Track section 12A Straight section 12B Curved section 14, 74 Running section 22, 76 Armature section 24 Track slab 30 Coil block 30A, 30B Coil blocks (first coil block, second coil block) 32(32U, 32V, 32W) Coil 34, 80 Frame (moving body) 36, 82 Field section 38 Caster (supporting means) 40(40A~40H) Permanent magnet 42(42U, 42V, 42W) Hall sensor (magnetic pole position detecting means) 44(44U, 44V, 44W) Optical sensor (moving body detecting means) 46(46A, 46B) Magnet blocks (first magnet block, second magnet block) 50 Control unit 106 Electrical angle calculation unit (electrical angle setting unit)

Claims

1. An orbital part extending along one direction, A moving body disposed opposite to the orbital part and movably supported along a moving surface including the one direction by a supporting means, An armature part in which a plurality of coil blocks in which coils corresponding to the number of phases are arranged in order in the one direction are arranged along the one direction in the orbital part, A field part disposed on the moving body opposite to the coils of the armature part, in which a plurality of permanent magnets are arranged in one or a plurality of electrical angle cycles along a direction corresponding to the one direction, and an end in a direction intersecting the arrangement direction of the permanent magnets faces an end in a direction intersecting the arrangement direction of the coils, Magnetic pole position detecting means that is provided at three locations in parallel with the arrangement direction of the coils with the same positional interval within the coil block in the range of one electrical angle cycle or two electrical angle cycles, and each detects a magnetic flux density corresponding to the magnetic pole position of the field part, An electrical angle setting unit that sets an electrical angle indicating the position of the reference magnetic pole with respect to the coil block of the field part based on a signal indicating the magnetic flux density detected by each of the magnetic pole position detecting means and the positional interval of the magnetic pole position detecting means, When moving the moving body along the one direction, a control unit that sets a d-axis current target value and a q-axis current target value, and excites each of the coils of the coil block with a drive voltage corresponding to the electrical angle, the d-axis current target value, and the q-axis current target value, An electromagnetic device including the above.

2. The electromagnetic device according to claim 1, wherein the electrical angle setting unit sets the electrical angle by correcting the electrical angle set based on a signal indicating the magnetic flux density detected by each of the magnetic pole position detecting means based on the positional interval of the magnetic pole position detecting means.

3. The electromagnetic device according to claim 1, wherein the magnetic pole position detecting means is arranged three by three for each coil block.

4. The magnetic pole position detecting means is grouped in sets of three, and a plurality of sets are arranged in the one direction, and the interval between the central positions of the adjacent sets in the one direction is an integral multiple of one electrical angle cycle. The electromagnetic device according to claim 3, including this.

5. The orbital part includes a curved part curved at a predetermined radius. When the coil blocks are arranged in the curved part, each of the coil blocks of the armature part is arranged such that the arrangement direction of the coils is the tangential direction in the curved part. The electromagnetic device according to claim 3, including this.

6. The field magnet portion includes a first magnet block in which the permanent magnets for one electrical angle period are arranged in a first direction corresponding to the one direction, and a second magnet block in which the permanent magnets for one electrical angle period are arranged in a second direction intersecting the first direction. The first magnet block and the second magnet block are adjacent to each other in the first direction and the second direction, and the first magnet blocks are diagonally adjacent to each other and the second magnet blocks are diagonally adjacent to each other. The armature portion includes, as the coil blocks, a first coil block in which the coils for the number of phases are arranged in the one direction, and a second coil block in which the coils for the number of phases are arranged in a direction intersecting the one direction. The first coil block and the second coil block are alternately arranged in each of the one direction and the direction intersecting the one direction. The electrical angle setting unit sets the electrical angle with respect to the coil block in which the coils are arranged along the moving direction of the moving body. The control unit excites the coils of the coil block in which the coils are arranged along the moving direction of the moving body. The electromagnetic device according to claim 1, including this.

7. The electromagnetic device according to claim 1, wherein the field magnet portion has the permanent magnets arranged such that the magnetization direction is changed by an angle obtained by dividing one electrical angle period by an integer of 3 or more as the number of divisions.

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