Conveyance system, processing system, and article manufacturing method

Abstract

To provide a levitation type transport system, a processing system, and a method for manufacturing goods, capable of transporting a plurality of movable elements with higher accuracy.SOLUTION: A transportation system has: movable members capable of moving along a first direction; stators that each have a plurality of coils arranged along the first direction, and each apply a force to the movable member to transport the movable member in the first direction while floating, by the plurality of coils to which electric current is applied, in a second direction intersecting the first direction; and a control unit that controls operation of the movable member by controlling the current applied to the plurality of coils. The control unit controls a levitation posture of the movable member by controlling the current applied to the plurality of coils and using machine difference information of the movable member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a conveyance system, a processing system, and a method for manufacturing an article. [Background technology]

[0002] Conveyance systems are generally used in production lines for assembling industrial products, semiconductor exposure equipment, and the like. In particular, conveyance systems in production lines use multiple movers to transport workpieces such as parts between multiple stations within a factory-automated production line or between production lines. They are also sometimes used as conveyance devices within process equipment. As conveyance systems, linear motor-based conveyance systems and magnetic levitation-type conveyance systems have already been proposed.

[0003] In these conveyance systems, multiple movers convey workpieces such as components, but due to machining errors and assembly errors in the sensor reading surface, each mover has a mover error, which is a position error when moving.

[0004] Therefore, Patent Document 1 describes a method for controlling the energization of electromagnets in a linear motor-based transport system using position correction data for each transport vehicle to stop the transport vehicle at a target stop position. In the method described in Patent Document 1, position correction data for each transport vehicle is determined based on the movement error of each transport vehicle measured in advance using a common measuring jig. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5753060 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the method described in Patent Document 1 corrects the stop position of the carriage in contact with the rail on the X-axis, which is one axis in the traveling direction of the carriage. In a magnetic levitation type conveyance system, it is difficult to convey the levitated mover with high accuracy using only such correction.

[0007] An object of the present invention is to provide a floating-type transport system, a processing system, and a method for manufacturing an article that can transport a plurality of movers with higher precision. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a conveyance system comprising: a mover movable along a first direction; a stator having a plurality of coils arranged along the first direction, the plurality of coils having currents applied thereto so as to levitate the mover in a second direction intersecting the first direction while applying a force to the mover to transport the mover in the first direction; and a control unit that controls the currents applied to the plurality of coils to control the operation of the mover, wherein the control unit controls the attitude of the mover in the levitated state by controlling the currents applied to the plurality of coils using machine-to-machine difference information of the mover. [Effects of the Invention]

[0009] According to the present invention, in a levitation type transport system, it is possible to transport a plurality of movers with higher precision. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a configuration of a transport system according to a first embodiment of the present invention. [Figure 2] 1 is a schematic diagram showing a configuration of a transport system according to a first embodiment of the present invention. [Figure 3] 1 is a schematic diagram showing a coil and a configuration related to the coil in a transport system according to a first embodiment of the present invention. FIG. [Figure 4]FIG. 1 is a schematic diagram showing a control system for controlling a transport system according to a first embodiment of the present invention. [Figure 5A] 5 is a schematic diagram showing a method of acquiring a correction value for correcting a moving unit difference of a mover in the transport system according to the first embodiment of the present invention. FIG. [Figure 5B] 5 is a schematic diagram showing a method of acquiring a correction value for correcting a moving unit difference of a mover in the transport system according to the first embodiment of the present invention. FIG. [Figure 6] 5A and 5B are schematic diagrams showing an example of data acquired in a method for acquiring a correction value for correcting a moving unit difference of a mover in the transport system according to the first embodiment of the present invention. [Figure 7] 3A and 3B are schematic diagrams illustrating a method for controlling the attitude of a mover in the transfer system according to the first embodiment of the present invention. [Figure 8] 3 is a schematic diagram showing an example of a control block for controlling the position and attitude of a mover in the transfer system according to the first embodiment of the present invention. FIG. [Figure 9A] FIG. 4 is a schematic diagram illustrating processing using a mover position calculation function in the transfer system according to the first embodiment of the present invention. [Figure 9B] FIG. 4 is a schematic diagram illustrating processing using a mover position calculation function in the transfer system according to the first embodiment of the present invention. [Figure 10] FIG. 3 is a schematic diagram illustrating processing using a mover attitude calculation function in the transfer system according to the first embodiment of the present invention. [Figure 11A] FIG. 4 is a schematic diagram illustrating processing using a mover attitude calculation function in the transfer system according to the first embodiment of the present invention. [Figure 11B] FIG. 4 is a schematic diagram illustrating processing using a mover attitude calculation function in the transfer system according to the first embodiment of the present invention. [Figure 12] 1 is a schematic diagram showing the relationship between a force acting on a yoke plate attached to a mover and force components and torque components acting on a mover 101 in the transfer system according to the first embodiment of the present invention. FIG. [Figure 13]5 is a graph schematically showing a thrust constant profile in the Z direction in the transfer system according to the first embodiment of the present invention. [Figure 14A] 2 is a schematic diagram showing a coil of a stator in the conveyance system according to the first embodiment of the present invention. FIG. [Figure 14B] 2 is a schematic diagram showing a coil of a stator in the conveyance system according to the first embodiment of the present invention. FIG. [Figure 15] 5 is a graph schematically showing the relationship between the amount of current applied to the coil and the magnitude of the attractive force acting between the coil and the yoke plate in the transport system according to the first embodiment of the present invention. [Figure 16] 3 is a schematic diagram showing a mover in the transport system according to the first embodiment of the present invention, viewed from above and below along the Z direction. FIG. [Figure 17] 6 is a graph schematically showing a suction force profile in the Y direction in the transfer system according to the first embodiment of the present invention. [Figure 18A] 10 is a schematic diagram showing a method for acquiring an instrumental error in the position of a mover in the X direction over the entire area of ​​a linear scale in a transport system according to a second embodiment of the present invention. FIG. [Figure 18B] 10 is a schematic diagram showing a method for acquiring an instrumental error in the position of a mover in the X direction over the entire area of ​​a linear scale in a transport system according to a second embodiment of the present invention. FIG. [Figure 19] 10 is a graph showing the difference between the measurement values ​​of the laser interferometer and the measurement values ​​of the linear encoder when the mover is slid and moved in the X direction on a plurality of Z-axis rollers in the conveyance system according to the second embodiment of the present invention. [Figure 20] FIG. 10 is a schematic diagram showing an example of a control block for controlling the position and attitude of a mover in a transfer system according to a third embodiment of the present invention. [Figure 21A] FIG. 10 is a schematic view showing a method for measuring the weight of a mover in a transport system according to a fourth embodiment of the present invention. [Figure 21B] FIG. 10 is a schematic view showing a method for measuring the weight of a mover in a transport system according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] A first embodiment of the present invention will be described below with reference to FIGS. First, the configuration of a conveyance system 1 according to this embodiment will be described with reference to Figs. 1 to 3. Figs. 1 and 2 are schematic diagrams showing the configuration of a conveyance system 1 including a mover 101 and a stator 201 according to this embodiment. Note that Figs. 1 and 2 show the main parts of the mover 101 and the stator 201, respectively. Fig. 1 is a view of the mover 101 seen from diagonally above, and Fig. 2 is a view of the mover 101 and the stator 201 seen from the X direction, which will be described later. Fig. 3 is a schematic diagram showing coils 202, 207, and 208 in the conveyance system 1 and the configuration related to the coils 202, 207, and 208.

[0012] As shown in FIGS. 1 and 2 , a conveying system 1 according to this embodiment includes a mover 101 constituting a carrier, a carriage, or a slider, and a stator 201 constituting a conveying path. The conveying system 1 also includes an integrated controller 301, a coil controller 302, a coil unit controller 303, and a sensor controller 304. Note that FIG. 1 illustrates three movers 101a, 101b, and 101c as the mover 101, and two stators 201a and 201b as the stator 201. Hereinafter, when there is no need to distinguish between multiple possible components such as the mover 101 and the stator 201, a common numeral is used, and lowercase letters are added after the numerals to distinguish between them as needed. Furthermore, when distinguishing between the right-side and left-side components of the mover 101, a lowercase letter R indicating the right side or L indicating the left side is added after the lowercase letter.

[0013] The conveyance system 1 according to this embodiment is a conveyance system using an induction linear motor that generates an electromagnetic force between the coil 207 of the stator 201 and the conductive plate 107 of the mover 101 to apply a thrust in the X direction to the mover 101. The conveyance system 1 according to this embodiment is also a magnetic levitation type conveyance system that levitates the mover 101 and conveys it in a non-contact manner. The conveyance system 1 according to this embodiment constitutes a part of a processing system that also has a process device that processes the workpiece 102 conveyed by the mover 101.

[0014] The transport system 1 transports the mover 101 by, for example, the stator 201, thereby transporting the workpiece 102 held by the mover 101 to a process device that performs a processing operation on the workpiece 102. The process device is not particularly limited, but is, for example, a film formation device such as a vapor deposition device or a sputtering device that forms a film on a glass substrate, which is the workpiece 102. Note that although FIG. 1 shows three movers 101 for two stators 201, the present invention is not limited to this. In the transport system 1, one or more movers 101 can be transported on one or more stators 201.

[0015] Here, the coordinate axes, directions, etc. used in the following description are defined. First, the X axis is taken along the horizontal direction, which is the transport direction of the mover 101, and the transport direction of the mover 101 is defined as the X direction. The Z-axis is taken along the vertical direction, which is perpendicular to the X-direction, and the vertical direction is defined as the Z-direction. The vertical direction is the direction of gravity (mg direction). The Y-axis is taken along the direction perpendicular to the X- and Z-directions, and the direction perpendicular to the X- and Z-directions is defined as the Y-direction. The rotation direction around the X-axis is defined as the Wx-direction, the rotation direction around the Y-axis is defined as the Wy-direction, and the rotation direction around the Z-axis is defined as the Wz-direction. A "*" is used as a multiplication symbol. The center of the mover 101 is defined as the origin Oc, the Y+ side is defined as the R-side, and the Y- side is defined as the L-side. The transport direction of the mover 101 does not necessarily have to be horizontal. In this case, the transport direction can be defined as the X-direction, and the Y- and Z-directions can be similarly defined. The X-, Y-, and X-directions are not necessarily perpendicular to each other and can also be defined as directions that intersect each other. A displacement in the transport direction is defined as a position, a displacement in any other direction is defined as an orientation, and the combination of the position and orientation is defined as a state.

[0016] The symbols used in the following description are as follows: The symbols are used repeatedly for the coils 202, 207, and 208.

[0017] Oc: Origin of mover 101 Os: Origin of linear scale 104 Oe: Origin of stator 201

[0018] j: An index for identifying the coil (where j is an integer that satisfies 1≦j≦N, where N is an integer of 2 or greater.) N: Number of coils installed Ij: Amount of current applied to the jth coil

[0019] P: State including the position and orientation of the mover 101 (X, Y, Z, Wx, Wy, Wz) X(j,P): X coordinate of the jth coil as viewed from the center of the mover 101 in state P Y(j,P): Y coordinate of the jth coil as viewed from the center of the mover 101 in state P Z(j,P): Z coordinate of the jth coil as viewed from the center of the mover 101 in state P

[0020] T: Force applied to the mover 101 Tx: Force component in the X direction of force T Ty: Y-direction force component of force T Tz: Z-direction force component of force T Twx: Torque component of force T in the Wx direction Twy: Torque component of force T in the Wy direction Twz: Torque component of force T in the Wz direction

[0021] Ex(j,P): The force in the X direction acting on the mover 101 in state P when a unit current is applied to the j-th coil Ey(j,P): Y-direction force acting on the mover 101 in state P when a unit current is applied to the j-th coil Ez(j,P): Z-direction force acting on the mover 101 in state P when a unit current is applied to the j-th coil

[0022] Σ: Sum when index j is changed from 1 to N *: Matrix and vector multiplication M: Torque contribution matrix K: pseudocurrent vector (column vector) Tq: Torque vector (column vector) Is: Coil current vector (column vector) Fs: Coil force vector (column vector) M(a,b): Element of row a and column b of torque contribution matrix M

[0023] Inv(): Inverse matrix Tr(): Transposed matrix Tr(element 1, element 2, ...): A column vector with elements 1, 2, ...

[0024] 1, the mover 101 is configured to be movable along the X direction, which is the transport direction. The mover 101 has a yoke plate 103 and a conductive plate 107. The mover 101 also has a linear scale 104, a Y target 105, and a Z target 106. Furthermore, the mover 101 has an RFID (Radio Frequency Identification) tag 512, which is an information medium in which identification information for identifying each mover 101 is registered.

[0025] A plurality of yoke plates 103 are attached to a plurality of locations on mover 101. Specifically, yoke plates 103 are attached along the X direction to the ends of the R and L sides on the top surface of mover 101. Also, yoke plates 103 are attached along the X direction to the side surfaces of the R and L sides of mover 101. Each yoke plate 103 is an iron plate made of a material with high magnetic permeability, such as iron.

[0026] The conductive plate 107 is attached along the X direction at the center of the upper surface of the mover 101. There are no particular limitations on the conductive plate 107 as long as it is made of a conductive metal plate or other conductive material, but an aluminum plate or the like with low electrical resistance is preferred.

[0027] The locations and numbers of the yoke plate 103 and the conductive plates 107 are not limited to the above, and can be changed as appropriate.

[0028] The linear scale 104, the Y target 105, and the Z target 106 are attached and installed in positions on the mover 101 that can be read by a linear encoder 204, a Y sensor 205, and a Z sensor 206, which are installed on the stator 201, respectively.

[0029] The RFID tag 512 is attached to the mover 101 at a position where it can be read by the RFID reader 513. The RFID reader 513 is installed at a specific position on the conveyance path of the mover 101 in the conveyance system 1. An individual ID (Identification), which is identification information, is registered in the RFID tag 512 so that the mover 101 to which the RFID tag 512 is attached can be identified. Note that the mover 101 may be provided with an information medium such as a QR code (registered trademark) indicating the individual ID of the mover 101 instead of the RFID tag 512. In this case, instead of the RFID reader 513, a reader such as a scanner that reads the individual ID from the information medium can be used depending on the information medium.

[0030] The stator 201 includes coils 202 , 207 , and 208 , a linear encoder 204 , a Y sensor 205 , and a Z sensor 206 .

[0031] A plurality of coils 202 are attached to stator 201 along the X direction so as to be able to face, along the Z direction, yoke plates 103 placed on the top surface of mover 101. Specifically, the plurality of coils 202 are arranged in two rows along the X direction so as to be able to face, from above along the Z direction, two yoke plates 103 placed at the ends of the R and L sides on the top surface of mover 101.

[0032] A plurality of coils 208 are attached to stator 201 along the X direction so as to be able to face, along the Y direction, yoke plates 103 placed on the side surfaces of mover 101. Specifically, the plurality of coils 208 are arranged in two rows along the X direction so as to be able to face, from the sides along the Y direction, two yoke plates 103 placed on the R-side and L-side surfaces of mover 101.

[0033] A plurality of coils 207 are attached to stator 201 along the X direction so as to be able to face, along the Z direction, conductive plate 107 placed on the upper surface of mover 101. Specifically, the plurality of coils 207 are arranged in a row along the X direction so as to be able to face, from above along the Z direction, conductive plate 107 placed in the center of the upper surface of mover 101.

[0034] The stator 201 applies a force to the mover 101, which is movable along the conveyance direction, by means of the coils 202, 207, and 208 to which a current is applied, thereby moving the mover 101 along the conveyance direction while controlling the position and posture of the mover 101.

[0035] The locations of the coils 202, 207, and 208 are not limited to the above and can be changed as appropriate. The number of coils 202, 207, and 208 can also be changed as appropriate.

[0036] The linear encoder 204, the Y sensor 205, and the Z sensor 206 function as detection units that detect the position and posture of the mover 101 that moves along the transport direction.

[0037] The linear encoder 204 is attached to the stator 201 so as to be able to read the linear scale 104 attached to the mover 101. The linear encoder 204 detects the relative position of the mover 101 with respect to the linear encoder 204 by reading the linear scale 104.

[0038] The Y sensor 205 is attached to the stator 201 so as to be able to detect the distance in the Y direction from the Y target 105 attached to the mover 101. The Z sensor 206 is attached to the stator 201 so as to be able to detect the distance in the Z direction from the Z target 106 attached to the mover 101.

[0039] The mover 101 is designed to be transported with the workpiece 102 attached or held above or below it. Note that Fig. 2 shows a state in which the workpiece 102 is attached below the mover 101. Note that the mechanism for attaching or holding the workpiece 102 to the mover 101 is not particularly limited, and general attachment mechanisms, holding mechanisms, etc., such as mechanical hooks and electrostatic chucks, can be used.

[0040] 2 shows a case in which the mover 101 and the stator 201 are incorporated in the chamber of a deposition apparatus 701, which is an example of a process apparatus that processes the workpiece 102. The deposition apparatus 701 has a deposition source 702 that deposits vapor on the workpiece 102 attached to the mover 101. The deposition source 702 is installed at the bottom of the chamber of the deposition apparatus 701 so as to be able to face the workpiece 102 attached to the bottom of the mover 101. A thin film of metal, oxide, or the like is formed on the substrate, i.e., the workpiece 102 attached to the bottom of the mover 101, by deposition using the deposition source 702. In this way, the workpiece 102 is transported together with the mover 101, and the transported workpiece 102 is processed by the process apparatus to manufacture an article.

[0041] 1 also shows an area including a location where a structure 100, such as a gate valve, exists between stators 201a and 201b. The location where structure 100 exists is a location where electromagnets and coils cannot be arranged continuously between multiple stations within a production line or between production lines.

[0042] The transport system 1 is provided with a control system 3 that controls the transport system 1. The control system 3 can constitute a part of the transport system 1. The control system 3 has an integrated controller 301, a coil controller 302, a coil unit controller 303, and a sensor controller 304. The integrated controller 301 is communicatively connected to the coil controller 302 and the sensor controller 304. The coil controller 302 is communicatively connected to a plurality of coil unit controllers 303. The sensor controller 304 is communicatively connected to a plurality of linear encoders 204, a plurality of Y sensors 205, and a plurality of Z sensors 206. The coils 202, 207, and 208 are connected to each coil unit controller 303 (see FIG. 3).

[0043] The integrated controller 301 determines current command values ​​to be applied to the multiple coils 202, 207, and 208 based on outputs from the linear encoder 204, the Y sensor 205, and the Z sensor 206 transmitted from the sensor controller 304. The integrated controller 301 transmits the determined current command values ​​to the coil controller 302. The coil controller 302 transmits the current command values ​​received from the integrated controller 301 to each coil unit controller 303. The coil unit controller 303 controls the amount of current in the connected coils 202, 207, and 208 based on the current command values ​​received from the coil controller 302.

[0044] Furthermore, an RFID reader 513 is communicatively connected to the integrated controller 301. The RFID reader 513 acquires the individual ID of the mover 101 by reading the RFID tag 512 of the mover 101. The RFID reader 513 transmits the acquired individual ID to the integrated controller 301. The integrated controller 301 receives and recognizes the individual ID of the mover 101 transmitted from the RFID reader 513, and can identify the mover 101. The RFID reader 513 is installed at one or more positions on the transport path formed by the stator 201.

[0045] 3, one or more coils 202, 207, 208 are connected to the coil unit controller 303. A current sensor 312 and a current controller 313 are connected to each of the coils 202, 207, 208. The current sensor 312 detects the value of a current flowing through the connected coils 202, 207, 208. The current controller 313 controls the amount of current flowing through the connected coils 202, 207, 208.

[0046] The coil unit controller 303 commands the current controller 313 as to the desired current amount and timing for passing the current based on the current command value received from the coil controller 302. The current controller 313 detects the current value detected by the current sensor 312 and controls the current amount so that the desired current amount flows through each of the coils 202, 207, and 208.

[0047] Next, the control system for controlling the transport system 1 according to this embodiment will be further described with reference to Fig. 4. Fig. 4 is a schematic diagram showing the control system 3 for controlling the transport system 1 according to this embodiment.

[0048] 4, the control system 3 has an integrated controller 301, a coil controller 302, a coil unit controller 303, and a sensor controller 304. The control system 3 functions as a control unit that controls the conveyance system 1 including the mover 101 and the stator 201. The integrated controller 301 is communicably connected to the coil controller 302, the sensor controller 304, and an RFID reader 513.

[0049] A plurality of coil unit controllers 303 are communicatively connected to the coil controller 302. The coil controller 302 and the plurality of coil unit controllers 303 connected thereto are provided corresponding to the respective columns of coils 202, 207, and 208. Each coil unit controller 303 is connected to a coil 202, 207, or 208. The coil unit controller 303 can control the magnitude of the current in the connected coils 202, 207, or 208.

[0050] The coil controller 302 issues a target current value to each of the connected coil unit controllers 303. The coil unit controllers 303 control the amount of current in the connected coils 202, 207, and 208.

[0051] A plurality of linear encoders 204, a plurality of Y sensors 205, and a plurality of Z sensors 206 are communicatively connected to the sensor controller 304.

[0052] The multiple linear encoders 204 are attached to the stator 201 at intervals such that one of them can measure the position of one mover 101 even while the mover 101 is being transported. The multiple Y sensors 205 are attached to the stator 201 at intervals such that two of them can measure the Y target 105 of one mover 101. The multiple Z sensors 206 are attached to the stator 201 at intervals and in a plane such that three of the two rows can measure the Z target 106 of one mover 101.

[0053] Based on the outputs from the linear encoder 204, the Y sensor 205, and the Z sensor 206, the integrated controller 301 determines current command values ​​to be applied to the multiple coils 202 and transmits them to the coil controller 302. Based on the current command values ​​from the integrated controller 301, the coil controller 302 commands the coil unit controller 303 to determine the current value and timing for passing the current, as described above. In this way, the integrated controller 301 functions as a control unit, transports the mover 101 along the stator 201 in a non-contact manner, and controls the attitude of the transported mover 101 in six axes.

[0054] The integrated controller 301 can identify the mover 101 by the individual ID of the mover 101 received from the RFID reader 513 that reads the RFID tag 512 attached to the mover 101. This allows the integrated controller 301 to apply individual parameters to each mover 101 to control the operation of the mover 101.

[0055] Next, a method for acquiring a correction value for correcting the movement difference of the mover 101 according to this embodiment will be described with reference to Figs. 5A and 5B. Figs. 5A and 5B are schematic diagrams showing a method for acquiring a correction value for correcting the movement difference of the mover 101 in the conveyance system 1 according to this embodiment, and show a common measuring jig 500 used in common for multiple movers 101 when acquiring the correction values. Fig. 5A shows the common measuring jig 500 as seen in the -X direction. Fig. 5B shows the common measuring jig 500 as seen in the -Z direction.

[0056] The common measuring jig 500 has a linear encoder 204 similar to that of the stator 201, and a laser displacement meter 502 as distance measuring means. The linear encoder 204 is attached to the common measuring jig 500 so as to be able to read the linear scale 104 of the mover 101 attached to the common measuring jig 500. The laser displacement meter 502 is attached to the common measuring jig 500 so as to be able to detect the position in the X direction of the mover 101 attached to the common measuring jig 500. The common measuring jig 500 is used to acquire, for each of the multiple movers 101, mechanical difference information that is information regarding the movement mechanical difference of the mover 101. The movement mechanical difference of the mover 101 for which the mechanical difference information is acquired is the mechanical difference in each of the X direction, Y direction, and Z direction.

[0057] In the common measuring jig 500, the linear encoder 204 reads the linear scale 104 of the mover 101, thereby making it possible to detect the position in the X direction of the mover 101 installed on the common measuring jig 500. Furthermore, the position in the X direction of the mover 101 installed on the common measuring jig 500 can be detected by measurement using the laser displacement meter 502.

[0058] Furthermore, by using an RFID reader 513 to read the RFID tag 512 of the mover 101 attached to the common measuring jig 500, the mover 101 can be identified.

[0059] The mover 101 is placed on the common measuring jig 500 so as to simulate the floating state of the mover 101. In this case, the mover 101 may be supported at the Bessel point 501, or may be based on a butt (not shown). It is important to perform common placement with good reproducibility for a plurality of movers 101 on the common measuring jig 500.

[0060] Here, of the Z targets 106 of mover 101, the Z target 106 arranged on the +Y direction side, which is the right side when facing the +X direction, which is the direction of travel, is referred to as Z target 106R. Also, of the Z targets 106 of mover 101, the Z target 106 arranged on the -Y direction side, which is the left side when facing the +X direction, which is the direction of travel, is referred to as Z target 106L.

[0061] When obtaining correction values ​​for correcting the mover error, measurements are performed on the mover 101 mounted on a common measuring jig 500 using a three-dimensional measuring machine 503 and a laser displacement meter 502. Specifically, the three-dimensional measuring machine 503 measures the Y-direction position of the Y target 105, the Z-direction position of the Z target 106R, and the Z-direction position of the Z target 106L along the X direction. When measuring, measurements may be performed in increments of 1 mm in the X direction, for example, to reduce the amount of correction data. The laser displacement meter 502 also measures the X-direction position of the mover 101.

[0062] Similarly, for multiple movers 101, the Y-direction position of Y target 105, the Z-direction position of Z target 106R, and the Z-direction position of Z target 106L are measured along the X direction by a three-dimensional measuring machine 503. Similarly, for multiple movers 101, the X-direction position of each mover 101 is measured by a laser displacement meter 502.

[0063] FIG. 6 shows an example of data measured as described above for the Y target 105, the Z target 106R, and the Z target 106L of the mover 101.

[0064] 6, the upper part shows the Y target 105, Z target 106R, and Z target 106L to be measured, and the lower part shows a graph of the measured data. In the graph shown in the lower part, the horizontal axis indicates the X-axis position of the measurement point. The vertical axis indicates the error Err, which is the value obtained by subtracting the measured value from the design value when mover 101 is installed on common measurement jig 500. In the graph, Err105 indicates the error Err for Y target 105, Err106R indicates the error Err for Z target 106R, and Err106L indicates the error Err for Z target 106L.

[0065] The error Err is the deviation of the target surface read by each target sensor from the design value. That is, Err105 is a reading error specific to each mover 101 when the Y sensor 205 reads the Y target 105. Err106R is a reading error specific to each mover 101 when the Z sensor 206 reads the Z target 106R. Err106L is a reading error specific to each mover 101 when the Z sensor 206 reads the Z target 106L.

[0066] The reading error of the Y sensor 205 and the reading error of the Z sensor 206 are the movement machine difference in the attitude of each mover 101 when it is levitated. Hereinafter, the reading error of the Y sensor 205 is represented as Cy, and the reading error of the Z sensor 206 is represented as Cz. The reading error Cy is the movement machine difference in the Y direction of the mover 101. The reading error Cz is the movement machine difference in the Z direction of the mover 101. The reading errors Cy and Cz are used as correction values ​​for correcting the movement machine difference of the mover 101 in the transport control of the mover 101.

[0067] When the measured data is used as a correction value, data between a plurality of measurement points can be interpolated using a method such as Lagrange interpolation.

[0068] These reading errors Cy and Cz are associated with the individual ID of the mover 101 registered in the RFID tag 512 by the integrated controller 301 and stored as sensor machine difference information 521 (see FIG. 7) in a storage unit such as a semiconductor storage device or a magnetic storage device. Note that the reading errors Cy and Cz may be stored in an external storage device that the integrated controller 301 can refer to.

[0069] On the other hand, the mechanical difference Cx, which is the difference in the position of the mover 101 in the X direction, can be calculated by the following equation (X1) based on the measurement results obtained by the laser displacement meter 502. Cx=(Ref_Lx-Lx)-(Ref_Ex-Ex) …Formula (X1)

[0070] Here, Ex, Lx, Ref_Lx, and Ref_Ex respectively represent the following. Ex: Measurement value of linear encoder 204 attached to common measuring jig 500 Lx: Measurement value of laser displacement meter 502 Ref_Lx: Design value of the position in the X direction from the laser displacement meter 502 to the mover 101 Ref_Ex: Design value of the installation position of the linear encoder 204

[0071] In this way, a mobile mechanical error Cx is acquired, which is a mechanical error in the X direction of the mover 101. The mechanical error Cx in the position in the X direction is associated with the individual ID of the mover 101 registered in the RFID tag 512 by the integrated controller 301, and is stored as X direction mechanical error information 520 (see FIG. 7) in a storage unit such as a semiconductor storage device or a magnetic storage device. Note that the mechanical error Cx may be stored in an external storage device that the integrated controller 301 can refer to.

[0072] The attitude control method of the mover 101 executed by the integrated controller 301 will be described below with reference to FIG. 7. FIG. 7 is a schematic diagram showing the attitude control method of the mover 101 in the transportation system 1 according to this embodiment. FIG. 7 shows an outline of the attitude control method of the mover 101, focusing mainly on the data flow. As will be described below, the integrated controller 301 executes processing using a mover position calculation function 401, a mover attitude calculation function 402, a mover attitude control function 403, and a coil current calculation function 404. In this way, the integrated controller 301 controls the transportation of the mover 101 while controlling the attitude of the mover 101 in six axes. Note that instead of the integrated controller 301, the coil controller 302 can be configured to execute processing similar to that of the integrated controller 301.

[0073] First, mover position calculation function 401 calculates the number and positions of movers 101 on stators 201 constituting the conveyance path from measurement values ​​from multiple linear encoders 204, information on their mounting positions, and X-direction machine difference information 520 of movers 101. At this time, mover position calculation function 401 can correct the mover difference of each individual mover 101 by using X-direction machine difference information 520 stored in association with the individual ID registered in RFID tag 512 of mover 101.

[0074] Through the above calculations, mover position calculation function 401 updates mover position information (X) and number information of mover information 406, which is information related to mover 101. Mover position information (X) indicates the position of mover 101 on stator 201 in the X direction, which is the transport direction. The mover information 406 is prepared for each mover 101 on the stator 201, as shown by POS-1, POS-2, . . . in FIG.

[0075] Next, the mover attitude calculation function 402 identifies the Y sensor 205 and the Z sensor 206 that can measure each mover 101 from the mover position information (X) of the mover information 406 updated by the mover position calculation function 401 .

[0076] Next, the mover attitude calculation function 402 calculates attitude information (Y, Z, Wx, Wy, Wz), which is information about the attitude of each mover 101, and updates the mover information 406. The mover attitude calculation function 402 calculates the attitude (Y, Z, Wx, Wy, Wz) based on the values ​​output from the identified Y sensor 205 and Z sensor 206 and the sensor machine difference information 521 of the Y target 105, Z target 106R, and Z target 106L. At this time, the mover attitude calculation function 402 can correct the mover machine difference of each mover 101 by using the sensor machine difference information 521 stored in association with the individual ID registered in the RFID tag 512 of the mover 101. The mover information 406 updated by the mover attitude calculation function 402 includes mover position information (X) and attitude information (Y, Z, Wx, Wy, Wz).

[0077] Next, mover attitude control function 403 calculates applied force information 408 for each mover 101 from current mover information 406, including mover position information (X) and attitude information (Y, Z, Wx, Wy, Wz), and the target attitude value. Applied force information 408 is information regarding the magnitude of the force to be applied to each mover 101. Applied force information 408 includes information regarding the three-axis force components (Tx, Ty, Tz) and the three-axis torque components (Twx, Twy, Twz) of the force T to be applied. Applied force information 408 is prepared for each mover 101 on the stator 201, as shown by TRQ-1, TRQ-2, ... in FIG. 7, for example.

[0078] Here, the three-axis components of the force, Tx, Ty, and Tz, are the X-direction component, Y-direction component, and Z-direction component of the force, respectively. Furthermore, the three-axis components of the torque, Twx, Twy, and Twz, are the X-axis component, Y-axis component, and Z-axis component of the torque, respectively. The conveyance system 1 according to this embodiment controls the six-axis components of the force T (Tx, Ty, Tz, Twx, Twy, Twz), thereby controlling the posture of the mover 101 in six axes and controlling the conveyance of the mover 101.

[0079] Next, the coil current calculation function 404 determines the current command value 409 to be applied to each of the coils 202 , 207 , and 208 based on the applied force information 408 and the mover information 406 .

[0080] In this way, the integrated controller 301 executes processing using the mover position calculation function 401, the mover attitude calculation function 402, the mover attitude control function 403, and the coil current calculation function 404, thereby determining the current command value 409. The integrated controller 301 transmits the determined current command value 409 to the coil controller 302.

[0081] The control of the position and attitude of the mover 101 will be described in more detail with reference to Fig. 8. Fig. 8 is a schematic diagram showing an example of a control block for controlling the position and attitude of the mover 101.

[0082] 8, P is the position and orientation (also referred to as position, orientation, or state) of the mover 101, and has components (X, Y, Z, Wx, Wy, Wz). ref is the target value of (X, Y, Z, Wx, Wy, Wz). err is the deviation between the target value ref and the position and orientation P.

[0083] The mover attitude control function 403 calculates the force T to be applied to the mover 101 to achieve the target value ref based on the magnitude of the deviation err, the change in the deviation err, the integrated value of the deviation err, and the like.

[0084] Based on the force T to be applied and the position and attitude P, the coil current calculation function 404 calculates the coil current I to be applied to the coils 202, 207, and 208 in order to apply the force T to the mover 101. When the coil current I calculated in this way is applied to the coils 202, 207, and 208, the force T acts on the mover 101, and the position and attitude P change to the target value ref.

[0085] By configuring the control block in this way, it becomes possible to control the position and attitude P of the mover 101 to a desired target value ref.

[0086] Here, the processing by the mover position calculation function 401 will be described with reference to Figures 9A and 9B. Figures 9A and 9B are schematic diagrams for explaining the processing by the mover position calculation function.

[0087] In Fig. 9A, reference point Oe is the position reference of stator 201 to which linear encoder 204 is attached. Also, reference point Os is the position reference of linear scale 104 attached to mover 101. Fig. 9A shows a case in which two movers 101a and 101b are transported as movers 101, and three linear encoders 204a, 204b, and 204c are arranged as linear encoders 204. Note that linear scale 104 is attached along the X direction at the same position on each of movers 101a and 101b.

[0088] For example, one linear encoder 204c faces the linear scale 104 of the mover 101b shown in Figure 9A. The linear encoder 204c reads the linear scale 104 of the mover 101b and outputs the distance Pc. The position on the X-axis of the linear encoder 204c, with the reference point Oe as the origin, is Sc. Therefore, the position Pos(101b) of the mover 101b can be calculated using the following equation (1). Pos(101b)=Sc-Pc...Equation (1)

[0089] For example, two linear encoders 204a and 204b face the linear scale 104 of the mover 101a shown in Figure 9A. The linear encoder 204a reads the linear scale 104 of the mover 101a and outputs the distance Pa. The position on the X-axis of the linear encoder 204a, with the reference point Oe as the origin, is Sa. Therefore, the position Pos(101a) of the mover 101a on the X-axis based on the output of the linear encoder 204a can be calculated using the following equation (2). Pos(101a)=Sa-Pa...Equation (2)

[0090] Furthermore, linear encoder 204b reads linear scale 104 of mover 101a and outputs distance Pb. Furthermore, the position on the X-axis of linear encoder 204b, with reference point Oe as the origin, is Sb. Therefore, the position Pos(101a)' of mover 101a on the X-axis based on the output of linear encoder 204b can be calculated by the following equation (3). Pos(101a)′=Sb-Pb…Equation (3)

[0091] Here, the position of each of the linear encoders 204a and 204b has been accurately measured in advance, so the difference between the two values ​​Pos(101a) and Pos(101a)' is sufficiently small. In this way, when the difference between the position of the mover 101 on the X-axis based on the outputs of the two linear encoders 204 is sufficiently small, it can be determined that the two linear encoders 204 are observing the linear scale 104 of the same mover 101.

[0092] In addition, when multiple linear encoders 204 face the same mover 101, the observed position of the mover 101 can be uniquely determined by, for example, calculating the average value of the positions based on the outputs of the multiple linear encoders 204.

[0093] Furthermore, the mover 101 can rotate around the Z axis by a rotation amount Wz. A case where the position of the mover 101 needs to be corrected due to a displacement of this rotation amount Wz will be described with reference to FIG. 9B. FIG. 9B describes a case where a linear scale 104 is attached to one of the Y-direction side surfaces of the mover 101b. Os is the origin of the linear scale 104, and Oc is the origin of the mover 101b. If the distance from the center Oc of the mover 101b to the linear scale 104 is D, then the position Pos(101b) of the mover 101b can be calculated using the following equation (1b) to obtain a more accurate position of the mover 101b. Pos(101b)=Sc-Pc-Wz*D...Formula (1b)

[0094] Furthermore, when the machine error Cx(101b), which is the machine error in the position of the mover 101b in the X direction, is taken into consideration, the position Pos(101b) of the mover 101b can be calculated using the following equation (1c) to obtain a more accurate position of the mover 101b. Pos(101b)=Sc-Pc-Wz*D+Cx(101b)...Formula (1c)

[0095] As described above, the mover position calculation function 401 calculates and determines the position X of the mover 101 in the X direction as mover position information based on the output of the linear encoder 204. When calculating the position X, the mover position calculation function 401 can correct the mover difference between individual movers 101 by taking into account the machine difference Cx of the position of the mover 101 in the X direction.

[0096] Next, the processing by the mover attitude calculation function 402 will be described with reference to FIGS. 10, 11A, and 11B.

[0097] Fig. 10 shows a case where mover 101c is transported as mover 101, and Y sensors 205a and 205b are arranged as Y sensor 205. Two Y sensors 205a and 205b face Y target 105 of mover 101c shown in Fig. 10. If the relative distance values ​​output by the two Y sensors 205a and 205b are Ya and Yb, respectively, and the distance between Y sensors 205a and 205b is Ly, then the amount of rotation Wz of mover 101c around the Z axis is calculated by the following equation (4). Wz=(Ya-Yb) / Ly ...Equation (4)

[0098] Here, the reading errors Cy of Y sensors 205a and 205b are assumed to be Cy(205a,101c) and Cy(205b,101c), respectively. Then, output values ​​Ya and Yb of Y sensors 205a and 205b can be corrected taking into account reading errors Cy(205a,101c) and Cy(205b,101c), respectively. Output values ​​Ya' and Yb' of Y sensors 205a and 205b after correction taking into account reading errors Cy(205a,101c) and Cy(205b,101c), respectively, are expressed by the following equations (4a) and (4b), respectively. Ya′=Ya+Cy(205a, 101c) …Formula (4a) Yb′=Yb+Cy(205b, 101c) …Equation (4b)

[0099] Furthermore, the amount of rotation Wz′ of the mover 101c around the Z axis after correction taking into account the reading errors Cy(205a, 101c) and Cy(205b, 101c) of the Y sensors 205a and 205b is calculated by the following equation (4c). Wz′=(Ya′-Yb′) / Ly …Equation (4c)

[0100] Depending on the position of the mover 101, three or more Y sensors 205 may face each other. In this case, the tilt of the Y target 105, i.e., the amount of rotation Wz' around the Z axis, can be calculated using the least squares method or the like.

[0101] 11A and 11B show a case where mover 101d is transported as mover 101, and Z sensors 206a, 206b, and 206c are arranged as Z sensors 206. Three Z sensors 206a, 206b, and 206c face Z target 106 of mover 101d shown in FIGS. 11A and 11B. Here, the relative distance values ​​output by the three Z sensors 206a, 206b, and 206c are designated Za, Zb, and Zc, respectively. Furthermore, the inter-sensor distance in the X direction, i.e., the distance between Z sensors 206a and 206b, is designated Lz1. Furthermore, the inter-sensor distance in the Y direction, i.e., the distance between Z sensors 206a and 206c, is designated Lz2. Then, the amount of rotation Wy around the Y axis and the amount of rotation Wx around the X axis can be calculated using the following equations (5a) and (5b), respectively. Wy = (Zb - Za) / Lz1 ...Equation (5a) Wx = (Zc - Za) / Lz2 ...Equation (5b)

[0102] Here, the reading errors Cz of Z sensors 206a, 206b, and 206c are assumed to be Cz(206a,101d), Cz(206b,101d), and Cz(206c,101d), respectively. Then, output values ​​Za, Zb, and Zc of Z sensors 206a, 206b, and 206c can be corrected by taking into account reading errors Cz(206a,101d), Cz(206b,101d), and Cz(206c,101d), respectively. Corrected output values ​​Za', Zb', and Zc' of Z sensors 206a, 206b, and 206c that take into account reading errors Cz(206a,101d), Cz(206b,101d), and Cz(206c,101d) are expressed by the following equations (5c), (5d), and (5e), ​​respectively. Za′=Za+Cz(206a, 101d) …Formula (5c) Zb′=Zb+Cz(206b, 101d) …Equation (5d) Zc′=Zc+Cz(206c, 101d) …Formula (5e)

[0103] Furthermore, the amount of rotation Wy′ around the Y axis of mover 101d after correction taking into account reading errors Cz(206a, 101d) and Cz(206b, 101d) of Z sensors 206a and 206b can be calculated by the following equation (5f). Wy′=(Zb′-Za′) / Lz1 …Equation (5f)

[0104] Furthermore, the amount of rotation Wx′ of mover 101d about the X axis after correction taking into account reading errors Cz(206a, 101d) and Cz(206c, 101d) of Z sensors 206a and 206c can be calculated by the following equation (5g). Wx′=(Zc′-Za′) / Lz2 …Equation (5g)

[0105] The mover posture calculation function 402 performs correction taking into account the reading error Cy of the Y sensor 205 and the reading error Cz of the Z sensor 206 as described above, and can calculate the rotation amounts Wx', Wy', and Wz' around each axis as posture information of the mover 101.

[0106] Furthermore, the mover attitude calculation function 402 can calculate the position Y in the Y direction and the position Z in the Z direction of the mover 101 as attitude information of the mover 101 as follows.

[0107] First, calculation of position Y of mover 101 in the Y direction will be described with reference to Fig. 10. In Fig. 10, two Y sensors 205 on which mover 101c is placed are designated Y sensors 205a and 205b. Measurement values ​​of Y sensors 205a and 205b are designated Ya and Yb, respectively. The midpoint between the positions of Y sensors 205a and 205b is designated Oe'. Furthermore, the position of the mover 101c obtained by equations (1) to (3) is Os', and the distance from Oe' to Os' is dX'. In this case, the position Y of the mover 101c in the Y direction can be calculated approximately using the following equation. Y=(Ya+Yb) / 2-Wz*dX′ …Equation (6)

[0108] The position Y of the mover 101c in the Y direction can be corrected taking into account the reading errors Cy(205a, 101c) and Cy(205b, 101c) of the Y sensors 205a and 205b. The position Y' of the mover 101c in the Y direction corrected taking into account the reading errors Cy(205a, 101c) and Cy(205b, 101c) can be calculated approximately using the following equation (6a): Y′=(Ya′+Yb′) / 2-Wz′*dX′ …Equation (6a)

[0109] Next, calculation of position Z of mover 101 in the Z direction will be described with reference to FIGS. 11A and 11B. The three Z sensors 206 over which mover 101d is mounted are designated Z sensors 206a, 206b, and 206c. Measurement values ​​of Z sensors 206a, 206b, and 206c are designated Za, Zb, and Zc, respectively. The X coordinate of Z sensor 206a is the same as the X coordinate of Z sensor 206c. Linear encoder 204 is located midway between Z sensors 206a and 206c. Position X of Z sensor 206a and Z sensor 206c is designated Oe" . The distance from Oe" to center Os" of mover 101d is designated dX". Position Z of mover 101d in the Z direction can be approximately calculated using the following equation: Z=(Za+Zb) / 2+Wy*dX″…Formula (7)

[0110] Position Z of mover 101d in the Z direction can be corrected taking into account reading errors Cz(206a,101d), Cz(206b,101d), and Cz(206c,101d) of Z sensors 206a, 206b, and 206c. Position Z' of mover 101d in the Z direction corrected taking into account reading errors Cz(206a,101d), Cz(206b,101d), and Cz(206c,101d) can be calculated approximately using the following equation (7a): Z′=(Za′+Zb′) / 2+Wy′*dX″…Formula (7a)

[0111] It should be noted that when the rotation amounts Wz and Wy of both positions Y and Z are large, the accuracy of the approximation can be further improved.

[0112] In this way, the integrated controller 301 executes processing using the mover position calculation function 401 and the mover attitude calculation function 402, thereby functioning as an acquisition unit that acquires the position and attitude of the mover 101. When acquiring the position and attitude of the mover 101, the integrated controller 301 can correct the position and attitude of the mover 101 by taking into account the machine error Cx of the position of the mover 101 in the X direction, as well as the reading error Cy of the Y sensor 205 and the reading error Cz of the Z sensor 206.

[0113] Next, a method for determining the current values ​​to be applied to the coils 202, 207, and 208 in order to apply a desired force T to the mover 101 will be described. As described above, the force T to be applied to the mover 101 has three-axis components of force Tx, Ty, and Tz, and three-axis components of torque Twx, Twy, and Twz. The integrated controller 301, which executes processing using the coil current calculation function 404, can determine the current values ​​to be applied to the coils 202, 207, and 208 in accordance with the method for determining the current values ​​described below.

[0114] Note that, among the forces and torques applied by coils 202, 207, and 208, there are cases where the influence of one force or torque on the other forces or torques can be sufficiently ignored. The forces and torques applied by coils 202, 207, and 208 are, specifically, the X-direction force applied by coil 207, the Y-direction force and Wz-direction torque applied by coil 208, and the Z-direction force, Wx-direction torque, and Wy-direction torque applied by coil 202. The Y-direction force and Wz-direction torque applied by coil 208 act in the horizontal direction. The Z-direction force, Wx-direction torque, and Wy-direction torque applied by coil 202 act in the levitation direction. When the influence can be sufficiently ignored, the current value can be calculated by considering only the X-direction force for coil 207, only the Y-direction force and Wz-direction torque for coil 208, and only the Z-direction force, Wx-direction torque, and Wy-direction torque for coil 202. Below, a case where the influence can be sufficiently ignored will be described.

[0115] First, the currents applied to the coils 202 to apply the Z-direction force component Tz, the Wx-direction torque component Twx, and the Wy-direction torque component Twy to the mover 101 will be described with reference to FIGS. 12 to 14B.

[0116] FIG. 12 is a schematic diagram showing the relationship between the force acting on the yoke plate 103 attached to the mover 101 and the force component Tz and torque components Twx and Twy acting on the mover 101. In FIG.

[0117] 12, Fzj is the force applied by the j-th coil to the yoke plate 103. Here, j is an integer that satisfies 1≦j≦N, where N is the number of installed coils 202 and is an integer equal to or greater than 2. The torque applied by each force Fzj contributes to torque components Twx and Twy. The torque applied by each force Fzj is determined depending on the force Fzj and the distance between the point of application of the force Fzj and the center Oc of the mover 101.

[0118] 13 is a graph showing a thrust constant profile 601 in the Z direction. The thrust constant profile 601 shows a schematic representation of the attractive force acting on the yoke plate 103 when a unit current is applied to the levitation coil 202 facing the yoke plate 103. The magnitude of the attractive force changes continuously with movement in the X direction.

[0119] An example of the configuration of coil 202 will now be described with reference to Figures 14A and 14B. Figures 14A and 14B are schematic diagrams showing coil 202. Figure 14A is a diagram of coil 202 as seen from the Z direction, and Figure 14B is a diagram of coil 202 as seen from the X direction.

[0120] 14A and 14B, the coil 202 has a winding 210 and a core 211. A current is applied to the winding 210 by a current controller 313. When a current is applied to the winding 210, a magnetic path 212, which is a path for magnetic flux, is formed. The magnetic flux in the magnetic path 212 thus formed acts as an attractive force between the coil 202 and the yoke plate 103.

[0121] The relationship between the current applied to coil 202 and the magnitude of the force acting between coil 202 and yoke plate 103 will be described in more detail with reference to Fig. 14A to Fig. 15. Fig. 15 is a graph schematically showing the relationship between the current applied to coil 202 and the magnitude of the attractive force acting between coil 202 and yoke plate 103. In the graph shown in Fig. 15, the horizontal axis represents the amount of current I applied to coil 202, and the vertical axis represents the magnitude Fz of the attractive force acting between coil 202 and yoke plate 103. The graph shown in Fig. 15 shows an attractive force profile 604 indicating the magnitude Fz of the attractive force relative to the amount I of current.

[0122] When the gap in the Z direction between coil 202 and yoke plate 103 is constant, attractive force Fz is roughly proportional to the square of the amount of current I. Here, in the graph shown in Figure 15, F0 is the magnitude of the force acting on each coil on average, which is necessary to compensate for the gravitational force mg acting on mover 101.

[0123] Here, the numerical values ​​and symbols are set as follows: The bottom area of ​​the core 211 of one coil 202: S = 0.01 m 2 ] Part of the mass of the mover 101 compensated by one coil 202: F0 = 100 [N] (approximately 10 [kg]) Magnetic permeability of vacuum: μ0=4π×10 -7 Air gap: gap [m] Number of coil turns: n [turns] Coil current: I [A] Magnetic flux density between the core 211 and the yoke plate 103: B [T]

[0124] If the magnetic permeability of the core 211 and the yoke plate 103 is sufficiently large compared to the magnetic permeability of a vacuum, Fz and B can be approximately calculated by the following equations (8a) and (8b), respectively. Fz=S*B 2 / (2*μ0) …Equation (8a) B=n*I*μ0 / (2*gap) ...Equation (8b)

[0125] Here, when the number of turns N is 500 [turns] and the coil current I0 is 1.0 [A], the air gap gap can be calculated as 0.006266 [m] using equations (8a) and (8b).

[0126] Here, in the attraction force profile 604, the point where I=I0 and Fz=F0 is defined as Q. The area around this point Q will be described.

[0127] If the gap were to increase by 0.25 mm from 0.006266 [m], a larger magnetomotive force would need to be generated in coil 202 to compensate for the increased gap. If equations (8a) and (8b) are calculated to generate the same Fz with the gap set to 0.006516 [m], the coil current I is calculated to be 1.0399 [A]. With this current value, the fluctuation in the coil current value during movement of mover 101 is sufficiently smaller than the reference coil current I0.

[0128] Therefore, around point Q, the relationship shown in the following equation (8c) holds between the current dI applied in addition to the current I0 and the magnitude of the additional force dF generated in the Z-axis direction by the application of current dI. However, around the origin O, the relationship shown in equation (8c) does not hold. dF ∝ dI ...Equation (8c)

[0129] Here, the ratio of dF to dI is defined by the following equation (8d). dF / dI=Ez ...Equation (8d)

[0130] In the thrust constant profile 601 shown in FIG. 13, Ez(j, P) is shown. Ez(j,P) is the ratio shown in equation (8d). That is, Ez(j,P) is the ratio of the magnitude dF of the force additionally generated in the Z-axis direction to the current dI when a current dI is additionally applied to the current I0 that is applied on average to the j-th coil 202 when the mover 101 is in the position and posture P.

[0131] 12, the description will be made according to the above notational method, with j being an index for identifying the coil 202. For simplicity, the additional force dFzj in the Z direction will be simply denoted as Fzj, and the additional current dIj will be denoted as Ij below.

[0132] The additional force Fzj in the Z direction generated by the j-th coil 202 is expressed by the following equation (9a), where Ij is the additional current applied to the j-th coil 202. Fzj=Ez(j,P)*Ij …Equation (9a)

[0133] Furthermore, let X(j,P) be the relative position of the j-th coil 202 in the X direction as viewed from the center Oc of the mover 101, and let Y(j,P) be the relative position of the j-th coil 202 in the Y direction as viewed from the center Oc of the mover 101. Then, the force component Tz in the Z direction, the torque component Twx in the Wx direction, and the torque component Twy in the Wy direction are expressed by the following equations (9b), (9c), and (9d), respectively. Tz=Σ(Ez(j,P)*Ij) ...Equation (9b) Twx=Σ(-Ez(j,P)*Y(j,P)*Ij) …Equation (9c) Twy=Σ(Ez(j,P)*X(j,P)*Ij) …Formula (9d)

[0134] If a current Ij that satisfies the above equations (9b), (9c), and (9d) is applied to each coil 202, the desired force and torque components (Tz, Twx, Twy) can be obtained.

[0135] Here, the torque contribution matrix M is defined. The torque contribution matrix M is a matrix that indicates the magnitude of contribution to each of the force components and torque components (Tz, Twx, Twy) when a unit current is applied to each of the 1st to jth coils 202 when the mover 101 is in the position and attitude P. In this way, using the torque contribution matrix M and information regarding the contribution to each of the force components and torque components (Tz, Twx, Twy) due to the unit current applied to each coil 202, the current value to be applied to each coil 202 is determined.

[0136] In the torque contribution matrix M, the first row corresponds to the Z direction, the second row corresponds to the Wx direction, and the third row corresponds to the Wy direction. Then, elements M(1,j), M(2,j), and M(3,j) of the first row and jth column, the second row and jth column, and the third row and jth column of the torque contribution matrix M are expressed by the following equations (10a), (10b), and (10c), respectively. The torque contribution matrix M is a matrix with 3 rows and N columns. Note that the rows of the torque contribution matrix M are linearly independent of each other. M(1,j)=Ez(j,P)...Formula (10a) M(2,j)=-Ez(j,P)*Y(j,P)...Formula (10b) M(3,j)=Ez(j,P)*X(j,P)...Formula (10c)

[0137] Meanwhile, a column vector is introduced as the coil current vector Is, whose elements are the amounts of current I1 to IN applied to the 1st to Nth coils 202. The coil current vector Is is a column vector with N rows and 1 column expressed by the following equation (10d). Is=Tr(I1,I2,…,Ij,…,IN)…Formula (10d)

[0138] Here, the torque vector Tq is defined by the following equation (11). Tq = Tr(Tz, Twx, Twy) ... Equation (11)

[0139] Then, the following equation (12) is obtained from equations (9b) to (9d), (10a) to (10d), and (11). Tq=M*Is…Equation (12)

[0140] Here, we introduce a pseudocurrent vector K. The pseudocurrent vector K is a column vector with 3 rows and 1 column, and if Tr(M) is the transpose matrix of the torque contribution matrix M, then it is a vector that satisfies the following equation (13). Tr(M)*K=Is...Equation (13)

[0141] By defining the coil current vector Is as expressed by equation (13), a larger current value can be applied to the coil 202 that contributes greatly to Tz, Twx, and Twy, thereby enabling current to be applied efficiently.

[0142] Equation (12) can be transformed into the following equation (14) using equation (13). Tq=M*Tr(M)*K...Equation (14)

[0143] In equation (14), M*Tr(M) is a square matrix with 3 rows and 3 columns, since it is the product of a 3-row, N-column matrix and an N-row, 3-column matrix. Furthermore, each row of the torque contribution matrix M is linearly independent of each other. Therefore, the inverse matrix of M*Tr(M) can always be obtained. Therefore, equation (14) can be transformed into the following equation (15). K=Inv(M*Tr(M))*Tq...Equation (15)

[0144] From equations (13) and (15), the coil current vector Is is finally obtained as expressed by the following equation (16): In this way, the coil current vector Is can be uniquely determined. Tr(M)*Inv(M*Tr(M))*Tq=Is...Equation (16)

[0145] Calculating the coil current vector Is in the above manner makes it possible to determine the current to be applied to each coil 202. This makes it possible to independently apply to the mover 101 a force component Tz in the Z direction, a torque component Twx in the Wx direction, and a torque component Twy in the Wy direction, thereby stabilizing the posture of the mover 101 in the Z direction, Wx direction, and Wy direction.

[0146] Next, the current applied to the coil 208 to apply the force component Ty in the Y direction and the torque component Twz in the Wz direction to the mover 101 will be described with reference to FIGS. 16 and 17. The force component Ty and the torque component Twz each act in the horizontal direction. FIG. 16 is a schematic diagram of the mover 101 viewed from above along the Z direction. FIG. 17 is a graph schematically showing an attractive force profile 605 in the Y direction. In the graph shown in FIG. 17, the horizontal axis represents the current applied to the coil 208, and the vertical axis represents the force acting on the mover 101.

[0147] For simplicity, Fig. 16 shows a case where four coils 208aR, 208bR, 208aL, and 208bL are arranged opposite to the mover 101 as the coils 208 installed on the stator 201. Furthermore, the coils 208aL and 208aR form a pair and operate as a single coil 208a. Furthermore, the coils 208bL and 208bR form a pair and operate as a single coil 208b. In this way, the j-th pair of coils 208jR and 208jL form a pair and operate as a single coil 208j.

[0148] 17, an attractive force profile 605 shows the relationship between the magnitudes IL and IR of the currents applied to the j-th pair of coils 208j and the magnitude of the force Fy acting on the mover 101. No repulsive force acts between the coils 208 and the yoke plate 103, but only an attractive force. Therefore, when a force is applied to the mover 101 in the Y+ direction, a current is applied to the R-side coil 208jR in a range 605a of the attractive force profile 605. Furthermore, when a force is applied to the mover 101 in the Y- direction, a current is applied to the L-side coil 208jL in a range 605b of the attractive force profile 605.

[0149] For example, when a force Fa in the Y+ direction is applied, a current Ia can be applied to the R-side coil 208jR. Also, when a force Fb in the Y- direction is applied, a current Ib can be applied to the L-side coil 208jL.

[0150] Let j be an index that identifies a pair of coils 208. Let X(j,P) be the relative position of the j-th pair of coils 208 in the X direction as viewed from the center Oc of the mover 101. Let Fyj be the force in the Y direction applied by the j-th pair of coils 208. Then, the horizontal Y-direction force component Ty and the Wz-direction torque component Twz are expressed by the following equations (17a) and (17b), respectively. Ty=ΣFyj …Equation (17a) Twz=Σ(-Fyj*X(j,P)) …Equation (17b)

[0151] Here, a Y-direction force vector Fys having Y-direction forces Fy1, Fy2, . . . , FyN applied by the first to Nth coils 208 as elements is defined by the following equation (17c). Fys=Tr(Fy1,Fy2,…,Fyj,…,FyN)…Formula (17c)

[0152] Furthermore, the torque vector Tq is defined by the following equation (17d). Tq=Tr(Ty,Twz) …Equation (17d)

[0153] In the torque contribution matrix M, the first row corresponds to the Y direction and the second row corresponds to the Wz direction. Then, elements M(1,j) and M(2,j) of the first row and jth column and the second row and jth column of the torque contribution matrix M are expressed by the following equations (17e) and (17f), respectively. M(1,j)=1 …Equation (17e) M(2,j)=X(j,P)...Formula (17f)

[0154] In order to calculate the current to be applied to the coil 208, first, a Y-direction force vector Fys that satisfies the following equation (17g) is determined. Tq=M*Fys…Formula (17g)

[0155] Since Tq is a 2-by-1 vector and M is a 2-by-N matrix, there are countless combinations of elements of the Y-direction force vector Fys that satisfy equation (17g), but they can be uniquely calculated using the following method.

[0156] Here, we introduce a pseudocurrent vector K with two rows and one column. If Tr(M) is the transpose matrix of the torque contribution matrix M, the pseudocurrent vector K is a vector that satisfies the following equation (17h). Tr(M)*K=Fys...Formula (17h)

[0157] Equation (17g) can be transformed into the following equation (17i) using equation (17h). Tq=M*Tr(M)*K...Formula (17i)

[0158] M*Tr(M) is a square matrix with 2 rows and 2 columns, since it is the product of a 2-row, N-column matrix and an N-row, 2-column matrix. Furthermore, each row of the torque contribution matrix M is linearly independent of each other. Therefore, the inverse matrix of M*Tr(M) can always be obtained. Therefore, equation (17i) can be transformed into the following equation (17j). K=Inv(M*Tr(M))*Tq...Formula (17j)

[0159] From equations (17h) and (17j), the Y-direction force vector Fys is finally obtained, which is expressed by the following equation (17k): This makes it possible to uniquely calculate the Y-direction force vector Fys. Tr(M)*Inv(M*Tr(M))*Tq=Fys...Formula (17k)

[0160] After the Y-direction force vector Fys is obtained, the current to be applied to each coil 208 can be calculated by back-calculating from the attraction force profile 605 that has been calculated or measured in advance.

[0161] In this manner, it is possible to determine the current to be applied to each coil 208. This makes it possible to apply the force component Ty in the Y direction and the torque component Twz in the Wz direction independently to the mover 101, thereby stabilizing the posture of the mover 101 in the Y direction and the Wz direction. For example, it is possible to apply a current to the coil 208 so that the torque in the Wz direction is always zero.

[0162] As described above, in this embodiment, the currents applied to the multiple coils 202, 208 are controlled by correcting the movement difference of the mover 101 in the Z direction and the movement difference in the Y direction. This controls the operation of the mover 101 so that it attains a target posture (Y, Z, Wx, Wy, Wz). Therefore, the postures of each of the multiple movers 101 can be controlled with higher accuracy. For example, by correcting the movement difference of the mover 101 in the Z direction and controlling the current values ​​applied to the multiple coils 202, the operation of the mover 101 is controlled so that it attains a target position in the Z direction. This controls the posture of the mover 101 while it is levitated. Therefore, the position of each of the multiple movers 101 during levitation can be controlled with higher accuracy.

[0163] Next, a method for controlling the coil 207 that applies a thrust in the X direction, which is the conveying direction, to the mover 101 will be described. The conveying system 1 according to this embodiment is a conveying system using an induction linear motor. The coil 207 generates an electromagnetic force between itself and the conductive plate 107 of the mover 101, and applies a thrust in the X direction, i.e., an X-direction force component Tx, to the mover 101. The conductive plate 107 is not particularly limited, but is preferably an aluminum plate with a relatively low electrical resistance.

[0164] When a current is applied to each coil 207, it generates a moving magnetic field in the X direction, which is the transport direction, and generates an electromagnetic force between the coil 207 and the conductive plate 107. As a result, each coil 207 generates a force component Tx as a thrust in the X direction, which is the transport direction, on the mover 101. If the speed of the mover 101 is insufficient, it is possible to increase the current applied to each coil 207 or change the timing of applying the current to each coil 207 so that the speed at which the moving magnetic field moves increases.

[0165] In this embodiment, the movement of the mover 101 is controlled to achieve a target transport speed by correcting the movement difference of the mover 101 in the X direction and controlling the value and / or timing of the current applied to the multiple coils 207. Therefore, the transport speed of each of the multiple movers 101 can be controlled with higher accuracy.

[0166] As described above, the integrated controller 301 determines and controls the current command values ​​of the currents to be applied to the coils 202, 207, and 208. In this way, the integrated controller 301 controls the attitude of the mover 101, which is carried by the stator 201, in six axes, while controlling the movement of the mover 101 on the stator 201 without contact. Note that all or part of the functions of the integrated controller 301 as a control device can be substituted by the coil controller 302 or other control devices.

[0167] In this embodiment, the case where the current in coil 207 is controlled in the same way as in coils 202 and 208 has been described, but the present invention is not limited to this. For example, a simpler configuration is possible in which an induction motor controller is connected to integrated controller 301, and the current in each coil 207 is controlled so that a constant moving magnetic field is generated by the induction motor controller.

[0168] As described above, according to this embodiment, six-axis force components and torque components (Tx, Ty, Tz, Twx, Twy, Twz) can be applied independently to the mover 101. Therefore, according to this embodiment, the mover 101 can be transported stably in the X direction in a non-contact manner while stabilizing the posture of the mover 101 in the Y direction, Z direction, Wx direction, Wy direction, and Wz direction.

[0169] Furthermore, according to this embodiment, the position and attitude of the mover 101 can be controlled taking into consideration the mechanical difference Cx in the position of the mover 101 in the X direction, as well as the reading error Cy of the Y sensor 205 and the reading error Cz of the Z sensor 206. This makes it possible to reduce or avoid the influence of the mechanical difference that may exist among the multiple movers 101. Therefore, according to this embodiment, the magnetic levitation type conveyance system 1 can convey the multiple movers 101 with higher accuracy.

[0170] In the above, the case where the mover error in the X direction, the mover error in the Y direction, and the mover error in the Z direction of the mover 101 are corrected has been described, but it is also possible to correct any one or two of these.

[0171] [Second embodiment] A second embodiment of the present invention will be described with reference to Figures 18A to 19. Note that components similar to those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted or simplified. Note that mobile device difference correction according to this embodiment can be performed in combination with mobile device difference correction according to the first embodiment.

[0172] In this embodiment, when obtaining a correction value for correcting the mechanical error of the mover 101, the mechanical error of the position of the mover 101 in the X direction is obtained over the entire area of ​​the linear scale 104. A method for obtaining the mechanical error of the position of the mover 101 in the X direction over the entire area of ​​the linear scale 104 will be described below with reference to FIGS. 18A and 18B. FIGS. 18A and 18B are schematic diagrams showing a method for obtaining the mechanical error of the position of the mover 101 in the X direction over the entire area of ​​the linear scale 104, and show a common measuring jig 510 that is used in common for multiple movers 101 when obtaining the correction value. FIG. 18A shows the common measuring jig 510 as viewed in the -X direction. FIG. 18B shows the common measuring jig 510 as viewed in the -Z direction.

[0173] Common measuring jig 510 has linear encoder 204 similar to that of stator 201, and laser interferometer 504 as distance measuring means. Linear encoder 204 is attached to common measuring jig 510 so as to be able to read linear scale 104 of mover 101 which is slid in the X direction on common measuring jig 510. Laser interferometer 504 is attached to common measuring jig 500 so as to be able to detect the X direction position of mover 101 which is slid in the X direction on common measuring jig 510.

[0174] The common measuring jig 510 has a plurality of Z-axis rollers 505. The plurality of Z-axis rollers 505 are arranged in two or more rows along the X direction. The Z-axis rollers 505 are, for example, ball rollers. The mover 101 is placed on the plurality of rows of Z-axis rollers 505. The Z-axis rollers 505 are capable of sliding the placed mover 101 in the X direction. Note that the common measuring jig 510 may also be provided with Y-axis rollers (not shown) to restrict the mover 101 in the Y direction when sliding in the X direction.

[0175] In common measuring jig 510, linear encoder 204 reads linear scale 104 of mover 101, thereby making it possible to detect the X-direction position of mover 101 sliding in the X-direction in common measuring jig 510. Furthermore, measurement by laser interferometer 504 makes it possible to detect the X-direction position of mover 101 sliding in the X-direction in common measuring jig 500.

[0176] 19 is a graph showing the difference, Err, between the measurement value of laser interferometer 504 and the measurement value of linear encoder 204 when mover 101 is slid in the X direction on multiple Z-axis rollers 505. When measuring with laser interferometer 504, measurements may be taken in 1 mm increments in the X direction, for example, to reduce the amount of correction data. When using the measured data as a correction value, data between multiple measurement points can be interpolated using a method such as Lagrange interpolation.

[0177] The mechanical difference Cx', which is the difference in the position of the mover 101 in the X direction, can be calculated by the following equation (X1)'. Cx′=(Ref_Lx′-Lx′)-(Ref_Ex′-Ex′) …Formula (X1)′

[0178] Here, Ex′, Lx′, Ref_Lx′, and Ref_Ex′ respectively represent the following. Ex′: Measurement value of the linear encoder 204 attached to the common measuring jig 510 Lx': Measurement value of laser interferometer 504 Ref_Lx′: Design value of the position in the X direction from the laser interferometer 504 to the mover 101 Ref_Ex′: Design value of the installation position of the linear encoder 204

[0179] The mechanical error Cx' can be obtained over the entire area of ​​the linear scale 104 based on the measurement results when the mover 101 is slid and moved in the X direction by the Z-axis roller 505. Note that the mechanical error Cx' does not necessarily have to be obtained over the entire area of ​​the linear scale 104, and may be obtained over a partial section of the linear scale 104.

[0180] The mechanical error Cx' in the position in the X direction is associated with the individual ID of the mover 101 registered in the RFID tag 512 and stored in the integrated controller 301 as X direction mechanical error information 520. When calculating the position X of the mover 101 in the X direction, the mechanical error Cx' associated with the individual ID of the mover 101 is taken into consideration.

[0181] In mover position calculation function 401, when mechanical error Cx(101b)', which is the mechanical error Cx' of the position of mover 101b in the X direction, is taken into consideration, the position Pos(101b)' of mover 101b can be calculated by the following equation (1c)' instead of equation (1c). Note that for mechanical error Cx(101b)', a value corresponding to the position of linear scale 104 read by linear encoder 204c can be used from among the values ​​acquired over the entire range of linear scale 104. Pos(101b)′=Sc-Pc-Wz*D+Cx(101b)′ …Formula (1c)′ By performing calculations using equation (1c)' that takes into account the machine error Cx', a more accurate position of the mover 101b can be obtained.

[0182] As described above, in this embodiment, when calculating the position X of the mover 101 in the X direction in the mover position calculation function 401, the mechanical error Cx' of the position of the mover 101 in the X direction acquired over the entire area of ​​the linear scale 104 is taken into consideration. The mechanical error Cx' is associated with the individual ID registered in the RFID tag 512 of the mover 101. This makes it possible to correct the mechanical error of each individual mover 101. Therefore, in this embodiment, no matter where the mover 101 is moved to, a more accurate current position can be acquired.

[0183] The integrated controller 301 can control the transport speed of the mover 101 by maintaining it at a constant speed, decelerating it, or accelerating it, based on the position of the mover 101 acquired as described above.

[0184] In this embodiment, no matter where the mover 101 is moving to, a more accurate current position can be obtained, so when the mover 101 is being transported at a target transport speed, the mover 101 can be made to follow the target transport speed more accurately. As a result, speed ripple, which is the speed variation of the mover 101 relative to the target transport speed, can be kept small. Therefore, according to this embodiment, the magnetic levitation type transport system 1 can transport multiple movers 101 with higher accuracy.

[0185] [Third embodiment] A third embodiment of the present invention will be described with reference to Figures 5A, 5B and 20. Note that the same components as those in the first and second embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0186] In this embodiment, a method for controlling the position and attitude of the mover 101 using information on the machine difference in the natural frequency of the mover 101 will be described. The mobile unit difference correction according to this embodiment can be performed in combination with the mobile unit difference correction according to the first or second embodiment.

[0187] First, the natural frequency of each mover 101 is measured. In measuring the natural frequency, as shown in the above-mentioned Figures 5A and 5B, the mover 101 whose natural frequency is to be measured is supported at its Bessel point 501. With the mover 101 supported in this manner, an acceleration sensor (not shown) is attached to the mover 101 and impact vibration is applied using, for example, hammering, and the natural frequency of the mover 101 is measured from the measurement results of the acceleration sensor at this time.

[0188] Next, the coefficients of the natural vibration elimination filter are determined from the measured natural vibration frequency of the movable element 101. As the natural vibration elimination filter, for example, a band-stop filter with a narrow stop band such as a notch filter can be used.

[0189] The integrated controller 301 associates this mechanical difference in natural frequency with the individual ID of the mover 101 registered in the RFID tag 512, and stores it in a storage device as mechanical difference information 522 of natural frequency (see FIG. 20). Note that the mechanical difference in natural frequency may be stored in an external storage device that the integrated controller 301 can refer to.

[0190] Operation correction using the machine-difference information of the natural frequency measured as described above will be described in further detail with reference to Fig. 20. Fig. 20 is a schematic diagram showing an example of a control block for controlling the position and attitude of the mover 101 when operation correction is performed using the machine-difference information of the natural frequency.

[0191] In FIG. 20, P is the position and orientation of the mover 101 with components (X, Y, Z, Wx, Wy, Wz), ref is the target value of (X, Y, Z, Wx, Wy, Wz), and err is the deviation between the target value ref and the position and orientation P.

[0192] 8 , the mover attitude control function 403 calculates the force T to be applied to the mover 101 to achieve the target value ref, based on the magnitude of the deviation err, the change in the deviation err, the integrated value of the deviation err, etc. In this embodiment, the integrated controller 301 executes processing using a filter function 514. The filter function 514 applies a natural vibration elimination filter to the force T to calculate a filtered force T′. When applying the natural vibration elimination filter, the integrated controller 301 determines the filter coefficient of the natural vibration elimination filter using the filter function 514 from machine difference information 522 of the natural frequency stored in association with the individual ID registered in the RFID tag 512 of the mover 101.

[0193] Based on the filtered force T' and the position and attitude P, the coil current calculation function 404 calculates the coil current I to be applied to the coils 202, 207, and 208 in order to apply the filtered force T' to the mover 101. When the coil current I calculated in this way is applied to the coils 202, 207, and 208, the filtered force T' acts on the mover 101, and the position and attitude P change to the target value ref.

[0194] By configuring the control block in this way, it becomes possible to control the position and attitude P of the mover 101 to a desired target value ref using information on the machine difference in the natural frequency of the mover 101.

[0195] As described above, in this embodiment, the filter function 514 applies the natural vibration elimination filter to the force T to be applied to the mover 101 to calculate the filtered force T'. The filter coefficient of the natural vibration elimination filter is determined from the machine difference information of the natural frequency stored in association with the individual ID registered in the RFID tag 512 of the mover 101. This makes it possible to control the position and attitude of each individual mover 101. Therefore, according to this embodiment, it is possible to transport multiple movers 101 with high precision.

[0196] [Fourth embodiment] A fourth embodiment of the present invention will be described with reference to Figures 21A and 21B. Note that the same components as those in the first to third embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0197] In this embodiment, a case where the weight of the mover 101 is measured will be described with reference to Figs. 21A and 21B. Figs. 21A and 21B are schematic diagrams showing a method for measuring the weight of the mover 101. Fig. 21A shows the common measuring jig 500 as seen in the -X direction. Fig. 21B shows the common measuring jig 500 as seen in the -Z direction.

[0198] When measuring the weight of the mover 101, as in the first embodiment, the mover 101 is supported at the Bessel point 501 of the mover 101 in the common measuring jig 500. In this embodiment, a weight sensor 511 that measures the weight of the mover 101 is installed on a support portion of the common measuring jig 500 that supports the mover 101.

[0199] For each of the multiple movers 101, the mover 101 can be placed on a common measuring jig 500 and the weight can be measured by a weight sensor 511. The weight sensor 511 is not particularly limited as long as it can measure the weight of the mover 101, but a load cell or the like can be used.

[0200] When multiple movers 101 are manufactured, manufacturing errors and assembly errors of parts can cause variations in weight among the multiple movers 101. From the viewpoint of transporting the multiple movers 101 with high precision, it is preferable that there is little or no variation in weight.

[0201] To correct the variation in weight of the movers 101, first, the weight of each of the multiple movers 101 is measured by the weight sensor 511 as described above. Next, based on the weight measurement results, the weights of the movers 101 are adjusted so that the weights of the multiple movers 101 are the same, for example, by installing weights on some or all of the multiple movers 101 or by changing components. This makes it possible to correct the variation in weight of the multiple movers 101 by reducing or eliminating it. By correcting the variation in weight in this way, the multiple movers 101 can be transported with high precision.

[0202] Furthermore, even if there is variation in the weight of the multiple movable elements 101, the multiple movable elements 101 can be transported with high precision by correcting the mechanical differences between the movable elements 101 as in the first to third embodiments described above.

[0203] [Modified embodiment] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above embodiment, the position and posture of the mover 101 are controlled in the X direction, Y direction, Z direction, Wx direction, Wy direction, and Wz direction, but the present invention is not limited to this. The position and posture can be controlled by acquiring displacement in at least one of the X direction, Y direction, Z direction, Wx direction, Wy direction, and Wz direction.

[0204] Furthermore, in the above embodiment, an example has been described in which the electromagnetic force received by the yoke plate 103 from the coil 202 is used as the levitation force for levitating the mover 101, but the present invention is not limited to this. For example, if the mass of the mover 101 or the mass of the workpiece 102 placed on the mover 101 is large and the levitation force to be applied in the vertical direction is large, the levitation force may be supplemented by separately using static pressure of a fluid such as air for levitation. Furthermore, the conveyance system 1 may also be configured as a levitation-type conveyance system that levitates the mover 101 using static pressure of a fluid or the like instead of electromagnetic force as the levitation force.

[0205] In the above embodiment, the case where the multiple coils 202, 207, and 208 are arranged in a predetermined number of rows has been described as an example, but the present invention is not limited to this. The coils can be arranged in a predetermined number of rows depending on the yoke plate 103 and conductive plate 107 arranged on the mover 101.

[0206] In the above embodiment, the case where the yoke plate 103 and the conductive plate 107 are provided on the mover 101 has been described as an example, but the present invention is not limited to this. The mover 101 may have a magnet group including a plurality of permanent magnets instead of the yoke plate 103 and the conductive plate 107. The magnet group may include, for example, a plurality of permanent magnets arranged along the X direction.

[0207] Furthermore, the conveying system according to the present invention can be used as a conveying system in a manufacturing system for manufacturing articles such as electronic devices, which conveys a workpiece together with a mover to the working area of ​​each process device, such as a machine tool, that performs each work process on the workpiece. The process device that performs the work process may be any device, such as a device that assembles parts on the workpiece or a device that paints it. Furthermore, the articles to be manufactured are not limited to specific ones, and may be any parts.

[0208] In this way, the conveying system according to the present invention can be used to convey a workpiece to a working area, and a work process can be performed on the workpiece conveyed to the working area to manufacture an article. Furthermore, the conveying object of the conveying system according to the present invention may be something other than a workpiece. For example, it may be an article other than a workpiece, or a living body such as a person or an animal. [Explanation of symbols]

[0209] 1. Transport system 3. Control System 101 Mover 102 Work 103 Yoke board 104 Linear Scale 105 Y Target 106 Z Target 107 Conductive plate 201 Stator 202 Coil 204 X Sensor 206 Z sensor 207 Coil 208 Coil 210 windings 211 cores 301 Integrated Controller 303 Coil Controller 304 Sensor Controller 302 Coil Controller 312 Current Sensor 313 Current Controller 500 Measuring Jig 502 Laser Displacement Meter 503 3D measuring instrument 504 Laser Interferometer 505 Z-axis roller 510 Measuring Jig 512 RFID tags 513 RFID Reader

Claims

1. a mover movable along a first direction; a stator having a plurality of coils arranged along the first direction, the plurality of coils to which a current is applied applying a force to the mover to levitate the mover in a second direction intersecting the first direction while transporting the mover in the first direction; a control unit that controls the current applied to the plurality of coils to control the operation of the mover; and The control unit controls the attitude of the mover during levitation by controlling the currents applied to the coils using machine difference information of the mover. A transport system characterized by:

2. The mechanical error information includes at least one of a first mechanical error related to the first direction of the mover, a second mechanical error related to the second direction, a third mechanical error related to a third direction intersecting the first direction and the second direction, a fourth mechanical error related to a natural frequency, and a fifth mechanical error related to a weight of the mover.

2. The transport system according to claim 1.

3. The machine difference information includes at least two of the first machine difference, the second machine difference, the third machine difference, the fourth machine difference, and the fifth machine difference.

3. The transport system according to claim 2.

4. The control unit controls the mover so as to achieve a target transport speed by controlling the current applied to the coils using the first mechanical error.

4. The transport system according to claim 2 or 3.

5. The control unit controls the mover to achieve the target attitude by controlling the currents applied to the coils using the second mechanical error and the third mechanical error.

5. The transport system according to claim 2, wherein the transport system is a transport system for transporting a plurality of objects.

6. The control unit controls the currents applied to the coils using the second mechanical error, thereby controlling the mover so that it reaches a target position in the second direction.

6. The transport system according to claim 5.

7. a storage unit that stores the machine difference information for each of the movable elements; 7. The transport system according to claim 1, wherein the transport system is a transport system for transporting a plurality of objects.

8. the movable element has an information medium in which identification information is registered, the machine difference information is associated with the identification information that identifies the mover, The control unit controls the currents applied to the coils using the machine difference information read from the information medium.

8. The transport system according to claim 7.

9. The second direction is the vertical direction.

9. The transport system according to claim 1, wherein the transport system is a transport system for transporting a plurality of objects.

10. The conveyance system according to any one of claims 1 to 9, wherein the machine difference information is obtained by measuring a plurality of the movers using a common measuring jig.

11. A transport system according to any one of claims 1 to 10; a process device that processes the workpiece transported by the mover; A processing system comprising:

12. A method for manufacturing an article using the processing system according to claim 11, a step of transporting the workpiece by the mover; performing the processing on the workpiece transported by the mover by the processing device; A method for manufacturing an article, comprising:

Images