JP7625411B2 - TRANSPORTATION APPARATUS, PRODUCTION SYSTEM, AND PRODUCTION METHOD OF ARTICLE - Google Patents

Description

The present invention relates to a transport system and a control method thereof.

Transport systems are generally used in production lines for assembling industrial products, semiconductor exposure equipment, and the like. In particular, transport systems in production lines transport parts and other workpieces within an automated production line or between multiple stations in a production line. They may also be used as transport devices within production equipment (process equipment). As a transport system, a transport system using a moving magnet type linear motor has already been proposed.

In a conveying system using a moving magnet type linear motor, a permanent magnet is placed on the mover, and the linear motor stator is installed on the frame so as to face the permanent magnet. Furthermore, the frame on which the stator is installed is equipped with a sensor that detects the mover. The position and attitude of the mover are calculated based on the detection data from this sensor, and the linear motor is driven and controlled based on this position and attitude.

For example, Patent Document 1 discloses a method for controlling a moving magnet type magnetic levitation transport device. The magnetic levitation transport device described in Document 1 is configured so that the mover is always facing three displacement sensors and six magnetic poles, and the displacement sensors measure the vertical distance to the mover, thereby identifying and controlling the three-dimensional coordinates of the mover.

Japanese Patent Application Publication No. 5-64315

In the above-mentioned conventional conveying system, in which a sensor installed on the stator side detects and controls the mover, in order to continuously calculate and control the position of the mover, it is necessary to convey the mover while switching sensors as it moves in the conveying direction.

Ideally, when the sensors are switched, the sensor that no longer detects the mover (exit sensor) and the sensor that starts to detect the mover (entrance sensor) should provide outputs indicating the same detection surface. However, differences in the sensor outputs occur due to factors such as the accuracy of sensor installation, differences between sensors, or differences in the surface condition of the mover to be detected, and the position and orientation calculated using this detection data fluctuate significantly. This causes problems such as undesirable behavior of the mover, such as vibration, which could not be sufficiently eliminated using the conventional technology described above. Furthermore, the vibrations can cause serious problems such as an inability to maintain stable transport of the mover or damage to the workpiece.

The present invention was made in consideration of these circumstances, and its purpose is to provide a transport device and a control method thereof that can transport a mover stably and smoothly.

A first aspect of the conveying device for solving the above problem comprises a mover that moves along a first direction, a stator that is arranged along the first direction and has a plurality of first sensors that detect position information of the mover, and a control unit that corrects the position information of the mover and controls the position and/or attitude of the mover based on at least one of the relative position between at least one of the plurality of first sensors and the mover obtained from the detection values of the plurality of first sensors and the detection time at which the plurality of first sensors detect the mover, and is characterized in that the control unit corrects the position information of the mover by weighting the detection value of a sensor that detects a position near the center of the mover more heavily than the detection value of a sensor that detects a position outside the center .

A second aspect of the conveying device for solving the above problem includes a stator having a mover moving along a first direction, a plurality of first sensors arranged along the first direction and detecting position information of the mover in the first direction, and a plurality of second sensors detecting position information of the mover in a second direction intersecting the first direction, and a control unit that selects at least one of the plurality of second sensors using detection values of the plurality of first sensors, corrects position information of the mover in the second direction based on the relative position of the selected second sensor and the mover, and controls the position and/or attitude of the mover, wherein the control unit corrects the position information of the mover by weighting the detection value of a sensor that detects a position near the center of the mover more heavily than the detection value of a sensor that detects a position outside the center .

According to the present invention, it is possible to minimize the fluctuation in the calculation results of the position of the movable element caused by switching the sensor during transportation, and the movable element can be transported stably and smoothly.

1 is a schematic diagram showing a conveying device according to a first embodiment of the present invention; 1 is a schematic diagram showing a conveying device according to a first embodiment of the present invention; 1 is a configuration diagram of a transport system showing a first embodiment of the present invention; FIG. 2 is a schematic diagram illustrating a data flow according to the first embodiment of the present invention. 5A and 5B are schematic diagrams illustrating conveyance direction position detection according to the first embodiment of the present invention. 5 is a schematic diagram illustrating a mover attitude calculation information process in a direction perpendicular to the transport direction according to the first embodiment of the present invention. FIG. 5 is a schematic diagram illustrating a function for calculating a coefficient based on installation position information of a sensor according to the first embodiment of the present invention. FIG. 8 is a schematic diagram illustrating a mover attitude calculation information process in a direction different from that in FIG. 7 that is orthogonal to the transport direction in the first embodiment of the present invention. FIG. 6 is a schematic diagram illustrating a mover attitude calculation process in a direction perpendicular to the transport direction according to the first embodiment of the present invention. FIG. 10 is a schematic diagram illustrating a mover attitude calculation process in a direction different from that in FIG. 9 that is orthogonal to the transport direction in the first embodiment of the present invention. FIG. 1 is a schematic diagram illustrating an effect of the first embodiment of the present invention. FIG. 5A to 5C are schematic diagrams illustrating different configurations of the mover attitude calculation information processing function in the first embodiment of the present invention. 4 is a schematic diagram showing a method of applying forces independently in the X direction and the Z direction to a permanent magnet in the first embodiment of the present invention. FIG. FIG. 11 is a schematic diagram showing an entire conveying system according to a second embodiment of the present invention. FIG. 11 is a configuration diagram of a transport system showing a second embodiment of the present invention. FIG. 11 is a schematic diagram illustrating a data flow according to a second embodiment of the present invention. 10A and 10B are schematic diagrams illustrating conveying direction position detection according to a second embodiment of the present invention. FIG. 11 is a schematic diagram illustrating the effect of the second embodiment of the present invention. FIG. 11 is a schematic diagram illustrating the effect of the second embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a second embodiment of the present invention. FIG. 11 is a schematic diagram showing a transport system according to a second embodiment of the present invention.

The conveying device according to this embodiment will be described with reference to the drawings.

Figures 1, 2(A) and 2(B) are schematic diagrams showing the conveying device according to this embodiment.

In Fig. 1, Fig. 2(A) and Fig. 2(B), 201 denotes a stator constituting the transport path, and 301 denotes a mover constituting a dolly, slider or carriage. Fig. 1 is a schematic diagram of the stator 201 and mover 301 of this embodiment as viewed from the Y direction. Fig. 2(A) is a schematic diagram of the stator 201 and mover 301 of this embodiment as viewed from the -X direction. Fig. 2(B) shows the arrangement of permanent magnets 303 on the upper surface of the mover 301. The left half of Fig. 2(A) shows a cross section (A) taken along the line (A)-(A) in Fig. 2B. The right half of Fig. 2(A) shows a cross section (B) taken along the line (B)-(B) in Fig. 2B.

Note that although one mover 301 is shown for the stator 201 in Figs. 1, 2(A) and 2(B), this is not limited to this. In the conveying device 1, multiple movers 301 can be conveyed on the stator 201.

The conveying device 1 according to this embodiment is preferably used to convey the workpiece 302 held by the movable element 301 to a production device by conveying the movable element 301 with the stator 201. Alternatively, it may be used as a conveying device in a production device (process device). By performing a processing operation, an inspection operation, or other operation (process operation) on the workpiece held by the movable element conveyed by the conveying device according to this embodiment, an article can be manufactured with high precision.

Note that in this specification, a system including a conveying device and a production device according to the embodiment may be referred to as a production system. In this specification, a production device refers to a device for performing operations such as processing or inspection on a workpiece, and examples of such operations include an inspection device, an assembly device, a semiconductor exposure device, and a deposition device. The production system according to this embodiment may have multiple production devices, and the multiple production devices may be production devices for performing the same operation on a workpiece, or may be production devices for performing different operations.

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 301, and the transport direction of the mover 301 is taken 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 taken as the Z-direction. The Y-axis is taken along a direction perpendicular to the X-direction and the Z-direction, and the direction perpendicular to the X-direction and the Z-direction is taken as the Y-direction. Rotation around the X-axis is taken as Wx, and rotation around the Y-axis and Z-axis is taken as Wy and Wz, respectively. Also, "*" is used as the symbol for multiplication, and "^" is used as the symbol for exponentiation. Also, the natural exponential function is expressed as exp(). Also, the Y+ side of the mover 301 is described as the R side, and the Y- side is described as the L side. Note that the transport direction of the mover 301 does not necessarily have to be horizontal, but in that case, the transport direction can be similarly defined as the X-direction, and the Y-direction and Z-direction can be similarly defined.

The conveying device 1 does not have a guiding device such as a linear guide, and is configured as a magnetic levitation type conveying device that conveys the mover 301 on the stator 201 in a non-contact manner.

As shown in FIG. 2B, the movable element 301 has permanent magnets 303aR, 303bR, 303cR, 303dR, 303aL, 303bL, 303cL, and 303dL as permanent magnets 303.

Permanent magnets 303aR, 303bR, 303cR, and 303dR are attached to the top surface of the R side of the mover 301. Permanent magnets 303aL, 303bL, 303cL, and 303dL are attached to the top surface of the L side of the mover 301. In the following, unless there is a need to distinguish between them, the permanent magnets of the mover 301 will simply be referred to as "permanent magnets 303". In addition, if there is no need to distinguish between the R side and the L side, but it is necessary to identify each permanent magnet 303 individually, each permanent magnet 303 will be identified individually using a code that ends with a lowercase alphabet as an identifier, excluding R or L, for each permanent magnet 303. In this case, each permanent magnet 303 will be identified individually by being written as "permanent magnet 303a", "permanent magnet 303b", "permanent magnet 303c", or "permanent magnet 303d".

The permanent magnets 303aR, 303dR are attached to one end and the other end in the X direction on the top surface of the R side along the X direction of the mover 301. The permanent magnets 303bR, 303cR are attached between the permanent magnets 303aR, 303dR on the top surface of the R side of the mover 301. The permanent magnets 303aR, 303bR, 303cR, 303dR are arranged, for example, at equal pitch in the X direction. Furthermore, the permanent magnets 303aR, 303bR, 303cR, 303dR are arranged so that their respective centers are aligned, for example, on a straight line along the X direction that passes through the center of the top surface of the R side of the mover 301.

The permanent magnets 303aL, 303dL are attached to one end and the other end in the X direction on the upper surface of the L side along the X direction of the mover 301. The permanent magnets 303bL, 303cL are attached between the permanent magnets 303aL, 303dL on the upper surface of the L side of the mover 301. The permanent magnets 303aL, 303bL, 303cL, 303dL are arranged, for example, at equal pitches in the X direction. Furthermore, the permanent magnets 303aL, 303bL, 303cL, 303dL are arranged so that their respective centers are aligned on a straight line along the X direction that passes through the center of the upper surface of the L side of the mover 301. Furthermore, the permanent magnets 303aL, 303bL, 303cL, 303dL are arranged in the same position in the X direction as the permanent magnets 303aR, 303bR, 303cR, 303dR, respectively.

In this embodiment, an example is shown in which the magnet group is on the top surface of the mover, but the magnet group may also be on the side surface of the mover.

Permanent magnets 303aR, 303bR, 303cR, and 303dR, which are arranged on the R side of the upper surface of the mover 301, are each located at a distance rx3 away from the origin O, which is the center of the mover 301, on the R side in the Y direction.

In addition, permanent magnets 303aL, 303bL, 303cL, and 303dL arranged on the L side of the upper surface of the mover 301 are arranged at a distance rx3 away from the origin O on the L side in the Y direction.

Permanent magnets 303a and 303d are attached at a distance rz3 from the origin O on one side in the X direction and the other side. Permanent magnets 303c and 303b are attached at a distance ry3 from the origin O on one side in the X direction and the other side.

On the top surface of the mover 301, the central portion between the R side portion where the permanent magnets 303 are arranged and the L side portion as described above is the portion on which the workpiece 302 to be transported is placed.

The permanent magnets 303aR, 303dR, 303aL, and 303dL are each a set of two permanent magnets arranged along the Y direction. The permanent magnets 303a and 303d are each configured by arranging two permanent magnets along the Y direction so that the polarity of the outer magnetic poles facing the stator 201 side alternates. The number of permanent magnets arranged along the Y direction constituting the permanent magnets 303a and 303d is not limited to two, but may be any number. In addition, the direction in which the permanent magnets constituting the permanent magnets 303a and 303d are arranged does not necessarily have to be the Y direction perpendicular to the X direction, which is the conveying direction, but may be any direction (second direction) that intersects with the X direction (first direction). In other words, the permanent magnets 303a and 303d may be a magnet group consisting of a plurality of permanent magnets arranged along a direction (second direction) that intersects with the X direction so that the polarity of the magnetic poles alternates.

On the other hand, permanent magnets 303bR, 303cR, 303bL, and 303cL are each a set of three permanent magnets arranged along the X direction. Permanent magnets 303b and 303c are each configured by arranging three permanent magnets along the X direction so that the polarity of the outer magnetic poles facing the stator 201 side alternates. Note that the number of permanent magnets arranged along the X direction constituting permanent magnets 303b and 303c is not limited to three, but may be any number. In other words, permanent magnets 303b and 303c may be a magnet group consisting of multiple permanent magnets arranged along the X direction so that the polarity of the magnetic poles alternates.

Each permanent magnet 303 is attached to a yoke 307 provided on the upper surface of the R side and L side of the mover 301. The yoke 307 is made of a material with high magnetic permeability, such as iron. In this specification, a material with high magnetic permeability refers to a material with a magnetic permeability of 5000 or more.

In this way, the movable element 301 on which the permanent magnet 303 is arranged has its posture controlled in six axes by the electromagnetic forces that the permanent magnet 303 receives from the multiple coils 202 of the stator 201, as described below, and is controlled to be movable in the X direction.

On the other hand, as shown in FIG. 2A, the stator 201 is attached with multiple coils 202 so as to be located above the top surface of the mover 301. The multiple coils 202 are attached to the stator 201 and arranged in two rows along the X direction so as to be able to face from above the permanent magnets 303 in the R-side and L-side parts of the top surface of the mover 301. The multiple coils 202 on the R side are arranged in one row along the X direction so as to be able to face from above the permanent magnets 303aR, 303bR, 303cR, and 303dR on the R side of the mover 301. The multiple coils 202 on the L side are arranged in one row along the X direction so as to be able to face from above the permanent magnets 303aL, 303bL, 303cL, and 303dL on the L side of the mover 301.

The mover 301 can move in the X direction along a plurality of coils 202 arranged in two rows along the X direction. The mover 301 is transported with the workpiece 102 to be transported placed on its upper surface. The mover 301 may have a holding mechanism, such as a work holder, that holds the workpiece 102 on the mover 301.

The stator 201 has multiple coils 202 arranged in two rows along the X direction, which is the transport direction of the mover 301. The stator 201 extends in the X direction, which is the transport direction, to form a transport path for the mover 301.

The multiple coils 202 are attached to the stator 201 and arranged in two rows along the X direction so that they can face the permanent magnets 303 on the R and L sides of the mover 301. The multiple coils 202 arranged in one row on the R side are arranged along the X direction so that they can face the permanent magnets 303aR, 303bR, 303cR, and 303dR on the R side of the mover 301. The multiple coils 202 arranged in one row on the L side are arranged along the X direction so that they can face the permanent magnets 303aL, 303bL, 303cL, and 303dL on the L side of the mover 301.

In this embodiment, the rows of coils 202 on the R side and L side of the mover 301 are arranged to face permanent magnets 303a, 303d and permanent magnets 303b, 303c, which are made up of multiple permanent magnets arranged in different directions. Therefore, with a small number of rows of coils 202, it is possible to apply a force to the mover 301 in the transport direction and a force different from the transport direction, as described below, and therefore it is possible to realize transport control and posture control of the mover 301.

The multiple coils 202 are arranged at a predetermined interval in the X direction. Each coil 202 is attached so that its central axis faces the Z direction. The coils 202 may be either cored or coreless.

The coils 202 are configured to be current-controlled in groups of, for example, three coils. The unit of coils 202 for which current is controlled is referred to as a "coil unit 203." When current is passed through the coils 202, electromagnetic force is generated between the coils 202 and the permanent magnets 303 of the mover 301, and force can be applied to the mover 301.

In FIG. 2B, permanent magnets 303a and 303d are each composed of a magnet group in which two permanent magnets are arranged in the Y direction. In contrast, each coil 202 is arranged so that the Y-direction centers of the two permanent magnets 303a and 303d coincide with the Y-direction center of coil 202. By passing current through coil 202 facing permanent magnets 303a and 303d, a force is generated in the Y direction on permanent magnets 303a and 303d.

The permanent magnets 303b and 303c are composed of a magnet group in which three permanent magnets are arranged in the X direction. By passing current through the coil 202 facing the permanent magnets 303b and 303c, forces are generated in the X and Z directions on the permanent magnets 303b and 303c. In this embodiment, permanent magnets are used as the magnets that make up the magnet group, but electromagnets may also be used.

101 shown in FIG. 2(A) is an X sensor (first sensor), which is, for example, a linear encoder that detects a linear scale 304 attached to the mover 301 and identifies the position of the mover 301 in the conveying direction. Also, 102 shown in FIG. 2(A) is a Y sensor (second sensor) that detects the Y-direction distance from the mover 301. A Z sensor 103 (third sensor) detects the Z-direction distance from the mover 301. For example, an eddy current sensor or the like may be disposed as the Y sensor or Z sensor. Note that the X sensor may also be configured as something other than a linear encoder, such as a laser interferometer.

The multiple X-sensors 101 (first sensors) are attached to the stator 201 along the X-direction (first direction) so that they can face the linear scale 304 of the mover 301. Each X-sensor 101 can detect the relative position of the mover 301 with respect to the X-sensor 101 by reading the linear scale 304 attached to the mover 301, and output the detection value.

The multiple Y sensors 102 (second sensors) are attached to the stator 201 along the X direction (first direction) so that they can face the Y targets 305 of the mover 301. Each Y sensor 102 can detect the relative distance in the Y direction between the Y target 305 attached to the mover 301 and output the detection value. Here, the Y target 305 is a convex part attached to the mover 301 and has a surface parallel to the target transport direction of the mover, and the surface parallel to the target transport direction of the mover is measured by the Y sensor 102 fixed to the stator. This makes it possible to detect the position and/or posture of the mover in the Y direction. The Y sensor 102 (second sensor) does not necessarily need to detect the relative distance in the Y direction perpendicular to the X direction, which is the transport direction, but only needs to be in a direction (second direction) that intersects with the X direction (first direction). It is also possible to directly detect the relative distance between the mover, but since it may be difficult to process the mover itself with high precision, in such cases the Y target 305 can be used.

The multiple Z sensors 103 (third sensors) are attached to the stator 201 in two rows along the X direction so that they can face the Z targets 306 of the mover 301. Each Z sensor 103 can detect and output the relative distance in the Z direction between the Z targets 306 attached to the mover 301. Here, the Z target 306 is a convex part attached to the mover 301 and has a surface perpendicular to the vertical direction, and the surface perpendicular to the vertical direction is measured by the Z sensor 103 fixed to the stator. This makes it possible to detect the vertical position and/or posture of the mover. The Z sensor 103 (third sensor) does not necessarily need to detect the relative distance in the Z direction perpendicular to the X direction, which is the conveying direction, but only needs to be in a direction (third direction) that intersects with the X direction (first direction). It is also possible to directly detect the relative distance between the mover, but since it may be difficult to process the mover itself with high precision, in such cases the Z target 306 can be used.

In this embodiment, an example is shown in which the X sensor 101, the Y sensor 102, and the Z sensor 103 are provided on the bottom of the stator, and the linear scale 304, the Y target 305, and the Z target 306 are provided on the bottom surface of the mover. However, this is not limited to this. The linear scale 304, the Y target 305, and the Z target 306 may be provided at any position on the mover, and the X sensor 101, the Y sensor 102, and the Z sensor 103 may be provided at any position on the stator as long as they are in a position that can face them. In addition, it is not necessary to provide both the Y sensor 102 and the Z sensor 103, and the effect of the present invention can be achieved even if only one of them is provided. For example, even if the Y sensor 102 is not provided, it can be applied to a conveying device that does not control the Y direction only by the attractive force of the magnet. In addition, even if the Z sensor 103 is not provided, it can be configured to not control the Z direction only by the attractive force of the magnet. Or it can be configured to float by another method such as air. Furthermore, it can be applied to an XY stage that does not perform levitation control in the Z direction.

Next, the control unit that controls the conveying device 1 according to this embodiment will be further described with reference to FIG. 3. FIG. 3 is a schematic diagram showing the control unit 3 that controls the conveying device 1 according to this embodiment.

As shown in FIG. 3, the control unit 3 has an integrated controller 401, a coil controller 402, and a sensor controller 404, and functions as a control unit that controls the conveying device 1 including the mover 301 and the stator 201. The coil controller 402 is communicatively connected to the integrated controller 401. The sensor controller 404 is also communicatively connected to the integrated controller 401.

A plurality of current controllers 403 are communicatively connected to the coil controller 402. The coil controller 402 and the plurality of current controllers 403 connected thereto are provided corresponding to each of the two rows of coils 202. A coil unit 203 is connected to each current controller 403. The current controller 403 can control the magnitude of the current in each of the coils 202 of the connected coil unit 203.

The coil controller 402 issues a target current value to each connected current controller 403. The current controller 403 controls the amount of current in the connected coil 202.

A number of X sensors 101, a number of Y sensors 102, and a number of Z sensors 103 are communicatively connected to the sensor controller 404.

The multiple X sensors 101 are attached to the stator 201 at intervals such that one of them can always measure the position of one of the movers 301 even while the mover 301 is being transported. The multiple Y sensors 102 are attached to the stator 201 at intervals such that two of them can always measure the Y target 305 of one of the movers 301. The multiple Z sensors 103 are attached to the stator 201 at intervals such that three of the two rows can always measure the Z target 306 of one of the movers 301.

The integrated controller 401 determines current command values to be applied to the multiple coils 202 based on the outputs from the X sensor 101, the Y sensor 102, and the Z sensor 103, and transmits them to the coil controller 402. The coil controller 402 issues a current value command to the current controller 403 as described above based on the current command value from the integrated controller 401. In this way, the integrated controller 401 functions as a control device, and transports the mover 301 along the stator 201 in a non-contact manner, while controlling the attitude of the transported mover 301 in six axes.

The attitude control method of the movable element 301 executed by the integrated controller 401 will be described below with reference to FIG. 4. FIG. 4 is a schematic diagram showing the attitude control method of the movable element 301 in the transport device 1 according to this embodiment. FIG. 4 shows an outline of the attitude control method of the movable element 301, focusing mainly on the data flow. As described below, the integrated controller 401 executes processing using a movable element position calculation function 501, a movable element attitude calculation information processing function 502, a movable element attitude calculation function 503, a movable element attitude control function 504, and a coil current calculation function 505. As a result, the integrated controller 401 controls the attitude of the movable element 301 in six axes while controlling the transport of the movable element 301. Note that instead of the integrated controller 401, the coil controller 402 can be configured to execute the same processing as the integrated controller 401.

First, the mover position calculation function 501 calculates the number and positions of the movers 301 on the stator 201 that constitutes the transport path from the measurement values from the multiple X sensors 101 and information on their mounting positions. As a result, the mover position calculation function 501 updates the mover position information (X) and number information of the mover information 506, which is information on the movers 301. The mover position information (X) indicates the position of the mover 301 on the stator 201 in the X direction, which is the transport direction. The mover information 506 is prepared for each mover 301 on the stator 201, for example, as shown as POS-1, POS-2, ... in Figure 4.

Next, the mover attitude calculation information processing function 502 identifies the Y sensor 102 and Z sensor 103 capable of measuring each mover 301 from the mover position information (X) of the mover information 506 updated by the mover position calculation function 501. At this time, the mover attitude calculation information processing function 502 calculates a coefficient (W) based on the sensor installation position information 507 on the stator 201 of the identified Y sensor 102 and Z sensor 103 and the mover position information (X).

The mover attitude calculation function 503 calculates attitude information (Y, Z, Wx, Wy, Wz) based on the detection values output from the identified Y sensor 102 and Z sensor 103 and the coefficient (W) calculated by the mover attitude calculation information processing function 502, and updates the mover information 506. The mover information 506 updated by the mover attitude calculation function 503 includes mover position information (X) and attitude information (Y, Z, Wx, Wy, Wz).

Next, the mover attitude control function 504 calculates applied force information 509 for each mover 301 from the current mover information 506, including mover position information (X) and attitude information (Y, Z, Wx, Wy, Wz), and the attitude target value. The applied force information 509 is information regarding the magnitude of the force to be applied to each mover 301. The applied force information 509 includes information regarding the three-axis components (Tx, Ty, Tz) of the force T to be applied and the three-axis components (Twx, Twy, Twz) of the torque. The applied force information 509 is prepared for each mover 301 on the stator 201, for example, as shown by TRQ-1, TRQ-2, ... in FIG. 4.

Next, the coil current calculation function 505 determines the current command value 510 to be applied to each coil 202 based on the applied force information 509 and the mover information 506.

In this way, the integrated controller 401 determines the current command value 510 by executing processing using the mover position calculation function 501, the mover attitude calculation information processing function 502, the mover attitude calculation function 503, the mover attitude control function 504, and the coil current calculation function 505. The integrated controller 401 transmits the determined current command value 510 to the coil controller 402.

The processing by the mover position calculation function 501 will now be described with reference to FIG. 5. FIG. 5 is a schematic diagram for explaining the processing by the mover position calculation function. FIG. 5 also shows the positional relationship of the linear scales 304a, 304b and the X-sensors 101a to 101f on the bottom surfaces of the movers 301a, 301b shown in FIG. 1 and FIG. 3 when the movers are viewed from the -Z direction shown in FIG. 1.

In FIG. 5, reference point Oe is the position reference of the stator 201 to which the X sensor 101 is attached. Also, reference point Os is the position reference of the linear scales 304a, 304b attached to the mover 301. FIG. 5 shows a case in which two movers 301a, 301b are transported as the mover 301, and three X sensors 101a, 101b, 101f are arranged as the X sensor 101. The linear scales 304a, 304b are attached in the X direction at the same positions on each of the movers 301a, 301b.

For example, one X-sensor 101f faces the linear scale 304b of the mover 301b shown in Fig. 5. The X-sensor 101f reads the linear scale 304b of the mover 301b and outputs the distance Pf. The position on the X-axis of the X-sensor 101f with the reference point Oe as the origin is Sf. Therefore, the position Pos(301b) of the mover 301b can be calculated by the following formula (1).
Pos (301b) = Sf - Pf...Formula (1)

For example, two X-sensors 101a and 101b face linear scale 304a of mover 301a shown in Fig. 5. X-sensor 101a reads linear scale 304a of mover 301a and outputs distance Pa. Furthermore, the position on the X-axis of X-sensor 101a with reference point Oe as the origin is Sa. Therefore, the position Pos(301a) of mover 301a on the X-axis based on the output of the detection value of X-sensor 101a can be calculated by the following equation (2).
Pos(301a)=Sa-Pa...Formula (2)

Furthermore, the X-sensor 101b reads the linear scale 304a of the mover 301a and outputs the distance Pb. The position on the X-axis of the X-sensor 101b with the reference point Oe as the origin is Sb. Therefore, the position Pos(301a)' of the mover 301a on the X-axis based on the output of the detection value of the X-sensor 101b can be calculated by the following equation (3).
Pos(301a)'=Sb-Pb...Equation (3)

Here, the installation positions of each of the X sensors 101a, 101b have been accurately measured in advance, so the difference between the two values Pos(301a) and Pos(301a)' is sufficiently small. In this way, when the difference in the position of the mover 301 on the X axis based on the output of the two X sensors 101 is sufficiently small, it can be determined that the two X sensors 101 are observing the linear scale 304 of the same mover 301.

When multiple X-sensors 101 face the same mover 301, the observed position of the mover 301 can be uniquely determined, for example, by calculating the average value of the positions based on the outputs of the multiple X-sensors 101. Alternatively, the position based on the output of the detection value of any one of the X-sensors 101 may be determined as the position of the mover 301.

The mover position calculation function 501 calculates and determines the position X of the mover 301 in the X direction as mover position information based on the output of the X sensor 101 as described above. The Y sensor 102 and Z sensor 103 capable of measuring each mover 301 are identified from the mover position information (X) of the mover information 506 updated by the mover position calculation function 501.

Next, the processing by the mover attitude calculation information processing function 502 will be explained using FIG. 6. The upper drawings in FIG. 6(A) and FIG. 6(B) show the positional relationship of the Y target 305 (305a) and the Y sensor 102 (102a-102c) on the bottom surface of the mover 301 (301a) shown in FIG. 1 when the mover is viewed from the -Z direction shown in FIG. 1. FIG. 6(B) shows a state in which the mover has advanced a little further along the +X direction compared to FIG. 6(A).

A first area is set in the center of the mover or the Y target of the mover as a detection target area, a second area is set at the end, and a third area is set between the first and second areas. Hereinafter, the first area may be referred to as the sensor information valid area 510A, the second area as the sensor information invalid area 512a, 512b, and the third area as the sensor information load area 511a, 511b.

As shown in the lower drawings in Figures 6(A) and 6(B), the sensor information valid area 510A is an area where the sensor information is determined to be valid (coefficient W is assigned as 1).

The sensor information invalid areas 512a and 512b are areas where the Y sensor 102 detects the edge of the Y target 305 and the output of the detection value is unstable, i.e., the detection error is equal to or greater than a certain level, and are provided to ignore the output of the detection value of the Y sensor (the coefficient W is set to 0).

The sensor information weighting areas 511a, 511b are areas between the sensor information valid area 510A and the sensor information invalid areas 512a, 512b, and are areas for weighting the sensor detection values according to their position within the area (the coefficient W is given a value between 0 and 1). In this way, the position information of the mover using the detection value of the Y sensor can be adjusted by the coefficient.

For example, the mover 301a shown in FIG. 6(A) has its mover position information (X) calculated as PosXa. Then, based on the relationship between PosXa and the sensor installation position information 507 of each of Sa, Sb, and Sc, the three Y sensors 102a, 102b, and 102c are identified as Y sensors capable of measuring the mover 301a.

Since the Y sensors 102a and 102b in FIG. 6A are determined to be present in the sensor information effective area 510A, the following calculations are made using the following expressions (4) and (5).
W(102a)=1...Formula (4)
W(102b)=1...Equation (5)

Since the Y sensor 102c in FIG. 6A is determined to be present in the sensor information invalid area 512b, the calculation is performed as in the following formula (6).
W(102c)=0...Formula (6)

Similarly, the mover 301a shown in FIG. 6(B) has mover position information (X) calculated as PosXa, and the multiple Y sensors 102a, 102b, and 102c are identified as measurable Y sensors.

Since the Y sensors 102b and 102c in FIG. 6B are determined to be present in the sensor information effective area 510A, the following equations (7) and (8) are used for the calculation.
W(102b)=1...Equation (7)
W(102c)=1...Formula (8)

Also, the Y sensor 102a in FIG. 6B is determined to be present in the sensor information load area 511a. When it is determined to be present in such a sensor information load area 511a, a coefficient (W) of 0 or more and 1 or less is calculated. For example, the coefficient (W) is calculated as a value of 0 or more and 1 or less using a continuous function that monotonically increases and decreases from 0 to 1 or from 1 to 0, such as a sigmoid function as shown in the following formula (9). In formula (9), a is the gain of the sigmoid function. FIG. 7A shows the function of the coefficient W. The dotted line in FIG. 7A is the function of the coefficient (W) in the sensor information load area 511a. Incidentally, the solid line is the function of the coefficient (W) in the sensor information load area 511b. In formula (9), Pa is the relative distance between the Y sensor 102a and the mover 301a calculated from PosXa, which is the mover position information (X), and Sa, which is the sensor installation position information 507 of the Y sensor 102a.
W(102a)=1/(1+exp(-a*Pa))...Equation (9)

The same process is performed for the Z sensor 103.

The upper drawings in Figures 8(A) and 8(B) show the positional relationship between the Z target 306 (306Ra) on the bottom surface of the mover 301 (301a) shown in Figure 1 and the Z sensors 103 (103Ra to 103Rc) when the mover is viewed from the -Z direction shown in Figure 1. Figure 8(B) shows the mover in a state where it has advanced a little further along the +X direction compared to Figure 8(A).

For example, the mover 301a shown in FIG. 8A has its mover position information (X) calculated as PosXa. Then, based on the relationship between PosXa and the sensor installation position information 507, SRa and SRb, the three Z sensors 103Ra, 103Rb, and 103Rc are identified as Z sensors capable of measuring the mover 301a.

Since Z sensors 103Ra and 103Rb in FIG. 8A are determined to be present in sensor information effective area 510B, calculation is performed as in the following expressions (10) and (11).
W(103Ra)=1...Formula (10)
W(103Rb)=1...Formula (11)

Since 103Rc in FIG. 8A is determined to be present in the sensor information invalid area 512d, it is calculated as in the following formula (12).
W(103Rc)=0...Formula (12)

Similarly, the mover 301a shown in FIG. 8(B) has mover position information (X) calculated as PosXa, and the multiple Z sensors 103Ra, 103Rb, and 103Rc are identified as measurable Z sensors.

Since Z sensors 103Rb and 103Rc in FIG. 8B are determined to be present in sensor information effective area 510B, calculations are performed as in the following expressions (13) and (14).
W(103Rb)=1...Formula (13)
W(103Rc)=1...Formula (14)

Also, the Z sensor 103Ra in FIG. 8B is determined to be present in the sensor information load area 511c. When it is determined to be present in such a sensor information load area 511c, a coefficient (W) of 0 or more and 1 or less is calculated. For example, the coefficient (W) is calculated as a value of 0 or more and 1 or less using a continuous function that monotonically increases and decreases from 0 to 1 or from 1 to 0, such as a sigmoid function as shown in the following formula (15). In formula (15), a is the gain of the sigmoid function. FIG. 7A shows the function of the coefficient W. The dotted line in FIG. 7A is the function of the coefficient (W) in the sensor information load area 511c. Incidentally, the solid line is the function of the coefficient (W) in the sensor information load area 511d. In equation (15), PRa is the relative distance between Z sensor 103Ra and mover 301a calculated from PosXa, which is mover position information (X), and SRa, which is sensor installation position information 507 of Z sensor 103Ra.
W(103Ra)=1/(1+exp(-a*PRa))...Formula (15)

The coefficient (W) calculated in the mover attitude calculation information processing function 502 described above is used to calculate the attitude information of the mover 301 in the mover attitude calculation function 503. This makes it possible to calculate the attitude of the mover 301 while continuously changing the valid and invalid states of the sensor information. This makes it possible to suppress discontinuous fluctuations in the detected position and attitude when the sensor used to calculate the mover information 506 is switched due to the transport of the mover 301.

In addition to the above-mentioned sigmoid function, the function for calculating the coefficient (W) can be replaced with a linear function as shown in FIG. 7(B) or a discontinuous function that changes the coefficient (W) stepwise as shown in FIG. 7(C). It can also be replaced with a hyperbolic function as shown in FIG. 7(D) and FIG. 7(E). The sigmoid function in FIG. 7(A) can smoothly change from 0 to 1, and the rate of change can be changed by adjusting the gain. In contrast, the linear function in FIG. 7(B) is uniquely determined by the sensor information load area 511 and can be processed quickly because it is composed of only the four arithmetic operations. In addition, the discontinuous function in FIG. 7(C) can be realized without the calculation process of the coefficient by storing it in the memory of the integrated controller 401 as a coefficient profile, and a complex coefficient profile other than the above function can also be set. In addition, PosSensor shown in FIG. 7 is the relative distance between the sensor and the movable element 301 calculated from the movable element position information (X) and the sensor installation position information 507.

In particular, the discontinuous function that changes the coefficient (W) stepwise as shown in FIG. 7(C) stores the coefficient (W) calculated based on the positional relationship between the mover 301 and each of the sensors 102 and 103 as a coefficient profile in the memory of the integrated controller 401. This makes it possible to configure the function to execute processing similar to that of the mover attitude calculation information processing function 502.

The mover attitude calculation information processing function 502 calculates the coefficient (W) from the mover position information (X) of the mover information 506 and the sensor installation position information 507 as described above. It outputs the mover attitude calculation information 508 to which the calculated coefficient (W) is added, and uses this information, together with the mover information 506, as an input to the mover attitude calculation function 503.

Next, the processing by the mover attitude calculation function 503 will be explained using Figures 9 and 10.

Figure 9 shows a case where mover 301c is transported as mover 301, and Y sensors 102s, 102t, and 102u are arranged as Y sensors 102. Three Y sensors 102s, 102t, and 102u face the Y target 305c of mover 301c shown in Figure 9. The relative distance values output by the three Y sensors 102s, 102t, and 102u are Ys, Yt, and Yu, respectively, and the measured values (detected values) are indicated by black circles in the figure. Then, the position of mover 301c, Y, and the amount of rotation Wz around the Z axis can be considered as the slope and intercept of the regression line.

Each parameter of the regression line Y=a*X+b, which is the mover position information (Y, Wz), can be found by, for example, using the least squares method to calculate a and b that minimize the loaded square error shown in the following equation (16). In this case, the slope a of the regression line is tan(Wz), and the intercept b is the position Y. In addition, in equation (16), Ws, Wt, and Wu are coefficients of the Y sensors 102s, 102t, and 102u included in the mover calculation information 508.
Ws*(Ys-(a*Ps+b))^2+Wt*(Yt-(a*Pt+b))^2+Wu*(Yu-(a*Pu+b))^2...Formula (16)

In addition, the mover position information (Y, Wz) of the mover 301 can be calculated if at least two Y sensors 102 face each other, but as mentioned above, depending on the position of the mover 301, three or more Y sensors 102 may face each other. In that case, too, the tilt of the Y target 305, i.e., the amount of rotation Wz around the Z axis and the position Y of the mover 301 can be calculated using the least squares method or the like.

From the viewpoint of the accuracy of detecting the posture of the movable element 301, it is desirable that the Y sensors 102 are installed on the stator 201 along the conveying direction (X) so that at least two sensors are present in the sensor information effective area 510 where the coefficient (W) is 1. In other words, it is desirable that the distance between adjacent Y sensors is equal to or less than half the length K (see Figures 6 (A) and (B)) in the X direction of the sensor information effective area 510A.

Also, FIG. 10 shows a case where mover 301d is transported as mover 301, and Z sensors 103d, 103e, and 103f are arranged as Z sensor 103. Three Z sensors 103d, 103e, and 103f face the Z target 306 of mover 301d shown in FIG. 10(A) and FIG. 10(B). Here, the relative distance values output by the three Z sensors 103d, 103e, and 103f are Zd, Ze, and Zf, respectively, and the measured values are indicated by black circles in the figure. Then, the position Z of mover 301d, the amount of rotation Wy around the Y axis, and the amount of rotation Wx around the X axis can be obtained as parameters of the regression plane.

Each parameter of the regression plane Z = d*X + e*Y + f, which is the mover position information (Z, Wx, Wy), can be found by, for example, using the least squares method to calculate d, e, and f that minimize the loaded square error shown in the following equation (17). In this case, d is tan(Wy), e is tan(Wx), and f is the position Z. In addition, in equation (17), Wd, We, and Wf are coefficients of each of Z sensors 103d, 103e, and 103f included in mover posture calculation information 508.
Wd*(Zd-(d*PdX+e*PdY+f))^2+We*(Ze-(d*PeX+e*PeY+f))^2+Wf*(Zf-(d*PfX+e*PfY+f))^2...Formula (17)

Depending on the position of the mover 301, four or more Z sensors 103 may face each other. In that case, the tilt of the Z target 306, i.e., the amount of rotation Wx around the X-axis and the amount of rotation Wy around the Y-axis, and the position Z of the mover 301 can be calculated similarly using the least squares method or the like.

From the viewpoint of the posture detection accuracy of the movable element 301, it is desirable to install at least one Z sensor 103 on either the R side or the L side and two on the other side along the conveying direction (X) in the sensor information effective area 510B where the coefficient (W) is 1. In this embodiment, an example of at least two sensors on the R side and at least one on the L side is shown, but it is also possible to install at least two sensors on the L side and at least one on the R side. In other words, in order to install at least two sensors in the sensor information effective area 510B, it is preferable that the distance between adjacent Z sensors 103 is half or less than the length L in the X direction of the sensor information effective area 510B (see Figures 8(A) and (B)). In order to install at least one sensor in the sensor information effective area 510B, it is preferable that the distance between adjacent Y sensors is equal to or less than the length L in the X direction of the sensor information effective area 510B (see Figures 8(A) and (B)).

As described above, the mover attitude calculation function 503 can calculate the position Y and position Z, and the rotation amounts Wx, Wy, and Wz around each axis as the attitude information of the mover 301.

Using the mover information 506 calculated above, the mover attitude control function 504 calculates the force T to be applied to the mover 301, and the coil current calculation function 505 determines the amount of current to be applied to each coil 202 from the force acting on each permanent magnet 303.

Next, the processing by the coil current calculation function 505 will be explained using FIG. 2(B). Note that in the force notation used below, the directions in which the forces act in the X, Y, and Z directions are indicated by x, y, and z, respectively, and the R side, which is the Y+ side in FIG. 2(B), is indicated by R, the L side, which is the Y- side, is indicated by L, the X+ side is indicated by f, and the X- side is indicated by b.

In FIG. 2(B), the forces acting on each permanent magnet 303 on the R side and L side are expressed as follows. The forces acting on each permanent magnet 303 are electromagnetic forces that the permanent magnet 303 receives from the multiple coils 202 to which current is applied. The permanent magnet 303 receives electromagnetic forces in the X direction, which is the direction in which the mover 101 is transported, as well as in the Y direction and Z direction, which are directions different from the X direction, from the multiple coils 202 to which current is applied.

The forces acting on the permanent magnet 303 on the R side are expressed as follows:
FzfR: force acting in the Z direction of the permanent magnet 303bR on the R side FxfR: force acting in the X direction of the permanent magnet 303bR on the R side FyfR: force acting in the Y direction of the permanent magnet 303aR on the R side FxbR: force acting in the X direction of the permanent magnet 303cR on the R side FybR: force acting in the Y direction of the permanent magnet 303dR on the R side FzbR: force acting in the Z direction of the permanent magnet 303cR on the R side

The forces acting on the L-side permanent magnet 303 are expressed as follows:
FzfL: force acting in the Z direction of the L-side permanent magnet 303bL FxfL: force acting in the X direction of the L-side permanent magnet 303bL FyfL: force acting in the Y direction of the L-side permanent magnet 303aL FxbL: force acting in the X direction of the L-side permanent magnet 303cL FybL: force acting in the Y direction of the L-side permanent magnet 303dL FzbL: force acting in the Z direction of the L-side permanent magnet 303cL

Moreover, the force T applied to the mover 301 is expressed by the following formula (18). Note that Tx, Ty, and Tz are three-axis components of the force, which are the X-direction component, the Y-direction component, and the Z-direction component of the force, respectively. Furthermore, Twx, Twy, and Twz are three-axis components of the moment, which are the X-axis component, the Y-axis component, and the Z-axis component of the moment, respectively. The transport device 1 according to this embodiment controls the transport of the mover 301 while controlling the posture of the mover 301 in six axes by controlling these six-axis components of the force T (Tx, Ty, Tz, Twx, Twy, Twz).
T=(Tx, Ty, Tz, Twx, Twy, Twz)...Equation (18)

Then, Tx, Ty, Tz, Twx, Twy, and Twz are calculated by the following equations (19a), (19b), (19c), (19d), (19e), and (19f), respectively.
Tx=FxfR+FxbR+FxfL+FxbL...Formula (19a)
Ty=FyfL+FyfR+FybL+FybR...Formula (19b)
Tz=FzbR+FzbL+FzfR+FzfL...Formula (19c)
Twx={(FzfL+FzbL)-(FzfR+FzbR)}*rx3...Formula (19d)
Twy={(FzfL+FzfR)-(FzbL+FzbR)}*ry3...Formula (19e)
Twz={(FyfL+FyfR)-(FybL+FybR)}*rz3...Formula (19f)

In this case, the limitations expressed by the following equations (19g), (19h), (19i), and (19j) can be introduced into the forces acting on the permanent magnets 303. By introducing these limitations, it is possible to uniquely determine a combination of forces acting on each permanent magnet 303 to obtain a force T having predetermined six-axis components.
FxfR=FxbR=FxfL=FxbL...Formula (19g)
FyfL=FyfR...Formula (19h)
FybL=FybR...Formula (19i)
FzbR=FzbL...Formula (19j)

Next, we will explain how the coil current calculation function 505 determines the amount of current to be applied to each coil 202 from the force acting on each permanent magnet 303.

First, we will explain the case where a force in the Z direction is applied to permanent magnets 303a and 303d, whose north and south poles are arranged alternately in the Y direction. Note that coil 202 is arranged so that its center in the Z direction is located at the center of permanent magnets 303a and 303d in the Y direction. This ensures that almost no forces acting in the X and Z directions on permanent magnets 303a and 303d are generated.

Let X be the position of the mover 301, j be the number of the coil 202 arranged in a row, Fy(j,X) be the magnitude of the force acting in the Y direction of the coil 202(j) per unit current, and i(j) be the current applied to the coil 202(j). Note that the coil 202(j) is the j-th coil 202. In this case, the current i(j) can be determined so as to satisfy the following equation (8). Note that the following equation (20) is an equation for the permanent magnet 303dR. The currents applied to the coils 202 of the other permanent magnets 303aR, 303aL, and 303dL can be determined in a similar manner.
ΣFy(j,X)*i(j)=FybR...Formula (20)

When multiple coils 202 exert a force on the permanent magnet 303, the force acting on the permanent magnet 303 can be uniquely determined by apportioning the current based on the magnitude of the force per unit current according to the force exerted by each coil 202.

Also, as shown in FIG. 2(B), the permanent magnets 303 are arranged symmetrically on the L side and R side of the mover 301. This symmetric arrangement of the permanent magnets 303 makes it possible to offset the multi-component forces acting on the permanent magnets 303, such as the force Wx acting on the permanent magnets 303a and 303d, i.e., the moment component around the X-axis, with the forces on the L side and R side. As a result, it becomes possible to control the attitude of the mover 301 with higher precision.

Next, a method of applying forces independently in the X and Z directions to permanent magnet 303b, in which north, south and north poles are alternately arranged in the X direction, will be described. FIG. 13 is a schematic diagram illustrating a method of applying forces independently in the X and Z directions to permanent magnet 303b. Coil current calculation function 505 determines the current command value to be applied to coil 202 in order to apply forces independently in the X and Z directions to permanent magnet 303b according to the following. Note that forces can also be applied independently in the X and Z directions to permanent magnet 303c, similar to permanent magnet 303b.

Let X be the position of the mover 301, j be the number of the coil 202 in the row, and let Fx(j,X) and Fz(j,X) be the magnitudes of the forces acting in the X and Z directions of coil 202(j) per unit current, respectively. Also, let i(j) be the magnitude of the current in coil 202(j). Note that coil 202(j) is the jth coil 202.

The top diagram in FIG. 13 is a diagram with the X axis running horizontally and the Y axis running vertically, showing six coils 202 facing permanent magnet 303bR. The middle diagram in FIG. 13 is a diagram of the top diagram in FIG. 13 viewed from the Y direction. The coils 202 are given numbers j from 1 to 6 in the order they are lined up in the X direction, and below each coil 202 will be identified by a notation such as coil 202(1).

As shown in the upper and middle figures in Figure 13, the coils 202 are arranged at a pitch of distance L. On the other hand, the permanent magnets 303 of the mover 301 are arranged at a pitch of distance 3/2*L.

The lower graph in FIG. 13 is a graph that shows a schematic representation of the magnitude of the X-direction force Fx and the Z-direction force Fz that are generated when a unit current is applied to each of the coils 202 shown in the upper and middle diagrams in FIG. 13.

For simplicity, in FIG. 13, the origin Oc of the X-direction position of coil 202 is set to the midpoint between coils 202(3) and 202(4), and the center Om of permanent magnet 303bR in the X-direction is set to the origin. Therefore, FIG. 13 shows the case where Oc and Om coincide, that is, where X=0.

In this case, for example, the force per unit current acting on coil 202(4) is Fx(4,0) in the X direction and Fz(4,0) in the Z direction. Also, the force per unit current acting on coil 202(5) is Fx(5,0) in the X direction and Fz(5,0) in the Z direction.

Here, the current values applied to coils 202(1) to 202(6) are i(1) to i(6), respectively. Then, the magnitude of force FxfR acting in the X direction and the magnitude of force FzfR acting in the Z direction on permanent magnet 303bR are generally expressed by the following equations (21) and (22), respectively.
FxfR = Fx (1, X) * i (1) + Fx (2, X) * i (2) + Fx (3, X) * i (3) + Fx (4, X) * i (4) + Fx (5, X) * i (5) + Fx (6,
FzfR = Fz (1, X) * i (1) + Fz (2, X) * i (2) + Fz (3, X) * i (3) + Fz (4, X) * i (4) + Fz (5, X) * i (5) + Fz (6,

By determining the current command value so that the current values i(1) to i(6) that satisfy the above formulas (21) and (22) are applied to the coils 202(1) to 202(6), respectively, it is possible to apply forces independently in the X and Z directions to the permanent magnet 303bR. The coil current calculation function 505 can determine the current command value to be applied to the coil 202(j) as described above in order to apply forces independently in the X and Z directions to the permanent magnet b303.

For simplicity's sake, consider an example in which, in the case shown in Figure 13, only coils 202(3), 202(4), and 202(5) of coils 202(1) to 202(6) are used for permanent magnet 303bR, and furthermore, the sum of the current values of these three is controlled to be 0. In this example, the force FxfR acting in the X direction and the force FzfR acting in the Z direction on permanent magnet 303bR are expressed by the following equations (23) and (24), respectively.
FxfR=Fx(3,X)*i(3)+Fx(4,X)*i(4)+Fx(5,X)*i(5)...Formula (23)
FzfR=Fz(3,X)*i(3)+Fz(4,X)*i(4)+Fz(5,X)*i(5)...Equation (24)

Moreover, the current values of the coils 202(1) to 202(6) can be set so as to satisfy the following expressions (25) and (26).
i(3)+i(4)+i(5)=0...Equation (25)
i(1)=i(2)=i(6)=0...Equation (26)

Therefore, when the magnitude of the force required for permanent magnet 303bR (FxfR, FzfR) is determined, the current values i(1), i(2), i(3), i(4), i(5), and i(6) can be uniquely determined. Forces are applied to the mover 301 in the X and Z directions by the current command value determined in this way. The force in the X direction applied to the mover 301 causes the mover 301 to gain a propulsive force to move in the X direction, and move in the X direction. In addition, the posture of the mover 301 is controlled by the forces in the X and Z directions applied to the mover 301 by the current command value determined in this way.

In this way, the integrated controller 401 controls each of the six axis components of the force applied to the mover 301 by controlling the current applied to the multiple coils 202.

When the center Oc of the coil 202 moves relative to the center Om of the permanent magnet 303bR due to the movement of the mover 301, that is, when X≠0, the coil 202 according to the moved position can be selected. Furthermore, a calculation similar to that described above can be performed based on the force per unit current generated in the coil 202.

As described above, the integrated controller 401 determines and controls the current command value of the current applied to the multiple coils 202, thereby controlling the attitude of the mover 301 on the stator 201 in six axes, while controlling the non-contact transport of the mover 301 on the stator 201. That is, the integrated controller 401 functions as a transport control means for controlling the transport of the mover 301, and controls the non-contact transport of the mover 301 on the stator 201 by controlling the electromagnetic force that the permanent magnet 303 receives from the multiple coils 202. The integrated controller 401 also functions as a posture control means for controlling the posture of the mover 301, and controls the posture of the mover 301 on the stator 201 in six axes. Note that all or part of the functions of the integrated controller 401 as a control device can be replaced by the coil controller 402 or other control devices.

In this way, according to this embodiment, six-axis forces, consisting of three-axis force components (Tx, Ty, Tz) and three-axis moment components (Twx, Twy, Twz), can be applied to the mover 301 by using multiple coils 202 arranged in two rows. This makes it possible to control the movement of the mover 301 while controlling the attitude of the mover 301 in six axes. According to this embodiment, two rows of coils 202, which is fewer rows than the number of six-axis components of the force, which is the variable to be controlled, can be used to control the movement of the mover 301 while controlling the attitude of the mover 301 in six axes.

Therefore, according to this embodiment, the number of rows of coils 202 can be reduced, so that the mover 301 can be transported in a non-contact manner while controlling the attitude of the mover 301 without increasing the size or complexity of the system. Furthermore, according to this embodiment, the number of rows of coils 202 can be reduced, so that a small magnetic levitation type transport system can be constructed at low cost.

In addition, according to this embodiment, since the permanent magnet 303 is disposed on the upper surface of the mover 301, good access to the workpiece 302 can be achieved. This allows the process device to perform machining operations on the workpiece 302 on the mover 301 with a high degree of freedom.

Next, the effects of the present invention will be explained using the example of detection by the Y sensor shown in Figure 11.

Figure 11 (A) shows how the Y target 305 attached to the mover 301 (not shown) moves as the mover 301 is transported, and the sensor installation positions of the multiple Y sensors 102a, 102b, and 102c differ due to variations in sensor installation accuracy.

As shown in Figures 11(B) to (E), as the mover 301 is transported, the Y sensor 102c begins to detect a new Y target 305 at the position indicated by PosXa in the figure.

Figure 11 (B) shows the calculation result of the mover position information (Y, Wz) using conventional technology that does not have a sensor information load area 511. This switching of the Y sensor 102 causes the calculation result of the mover position information (Y, Wz) to fluctuate greatly and discontinuously.

In contrast, the calculation results of the mover position information (Y, Wz) using the coefficient (W) calculated by the sigmoid function are shown in Figure 11 (C). Also, the results using the coefficient (W) calculated by a linear function are shown in Figure 11 (D), and the results using the coefficient (W) calculated by the discontinuous function as shown in Figure 7 (C) are shown in Figure 11 (E). In the area shown as the sensor information load area 511 in Figure 11, the coefficient (W) of the Y sensor 102c is calculated by each function and used to calculate the mover position information (Y, Wz).

The detection position and attitude when the detection sensor is switched should desirably change smoothly as shown in FIG. 11(C) from the viewpoint of suppressing vibration of the mover 301. However, even if they are configured with a linear function or a discontinuous function for implementation reasons such as speeding up the calculation process of the mover position information, it is possible to keep the above-mentioned fluctuations small as shown in FIG. 11(D) and (E).

The sensors used to calculate the mover information 506 are successively switched as the mover 301 is transported. At that time, the sensor installation positions change continuously with the coefficient (W) from sensor information invalid area 512b → sensor information load area 511b → sensor information valid area 510A → sensor information load area 511a → sensor information invalid area 512a. Therefore, according to this embodiment, it is possible to keep the fluctuations in the detection position and posture when the detection sensor is switched small. Therefore, it is possible to eliminate the vibration of the mover caused by switching of the detection sensor, and stable transport is possible.

In this embodiment, the sensor information load area 511 and the sensor information invalid area 512 are provided only in front of and behind the movable element 301. However, depending on the configuration of the movable element 301, the targets 305 and 306 may be divided and arranged in the conveying direction, or the targets 305 and 306 may float or deform due to variations in the installation accuracy. In this case, the detection of the sensors 102 and 103 may become unstable, and there may be multiple locations where the detection error is equal to or greater than a certain level. In such a case, as shown in FIG. 12, it is also possible to divide the Y target 305 into Y targets 3051 and 3052. Alternatively, it is also possible to divide the Z target 306R into 306R1 and 306R2, and 306L into 306L1 and 306L2. The sensor information valid area 510 is divided accordingly, and the sensor information load area 511 and the sensor information invalid area 512 are set.

This makes it possible to suppress fluctuations in the detection position and orientation caused by division of the Y target 305 and Z target 306, etc.

In this embodiment, the conveying device 1 is an example of a moving magnet type linear motor (moving permanent magnet type linear motor, moving field type linear motor), but this is not limited to this. The conveying device 1 may also be a moving coil type linear motor (moving coil type linear motor, fixed field type linear motor).

[Second embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings, using FIGS.

Figure 14 is a schematic diagram showing the entire conveying system according to the second embodiment. In the conveying system of the second embodiment, the movable member 301 is restricted by the guide rail 204 so that it does not move in the Y direction or the Z direction. In addition, the only sensor attached to the stator 201 is the X sensor 101. Below, the same reference numerals are used for configurations that have the same functions as in the first embodiment, and descriptions are omitted.

The conveying system 1001 according to the second embodiment has a mover 301 constituting a dolly, slider or carriage, a stator 201 constituting a conveying path, and a plurality of X-sensors 101 fixed to the stator 201. The conveying system 1001 is a conveying system using a moving magnet type linear motor (moving permanent magnet type linear motor, moving field type linear motor).

The movable member 301 is also restricted by the guide rail 204 so that it does not move in the Y and Z directions. In this embodiment, an example of restricting the movable member 301 by the guide rail 204 is shown, but the movable member 301 may be restricted in the Y and Z directions by a guide roller.

The X-sensor 101 is, for example, a linear encoder that detects a linear scale 304 attached to the movable element 301 and determines the conveying direction position of the movable element 301.

The multiple X-sensors 101 are attached to the stator 201 along the X-direction so that they can face the linear scale 304 of the mover 301. Each X-sensor 101 can detect and output the relative position of the mover 301 with respect to the X-sensor 101 by reading the linear scale 304 attached to the mover 301.

Next, the control system that controls the transport system 1001 according to this embodiment will be further described with reference to FIG. 15. FIG. 15 is a schematic diagram showing the control system that controls the transport system 1001 according to the second embodiment.

As shown in FIG. 15, the control system has a host controller 1400, an integrated controller 1401 (1401a and 1401b), a coil controller 1402, and a sensor controller 1404, and functions as a control device that controls a conveying system 1001 including a mover 301 and a stator 201. The integrated controller 1401 is communicatively connected to the host controller 1400. The coil controller 1402 is communicatively connected to the integrated controller 1401. In addition, the sensor controller 1404 is communicatively connected to the integrated controller 1401.

The host controller 1400 controls the entire production equipment, including the transport system 1001 and the process equipment that performs processing work on the workpiece 302 on the movable element 301. The host controller 1400 transmits movement commands (movement destination, movement speed, movement acceleration/deceleration, etc.) for each movable element 301 to the integrated controller 1401.

The coil controller 1402 is communicatively connected to a plurality of current controllers 1403 (not shown). The coil controller 1402 and the plurality of current controllers 1403 connected thereto are provided corresponding to the plurality of coils 202. A coil unit 203 is connected to each current controller 1403. The current controller 1403 can control the magnitude of the current in each coil 202 of the connected coil unit 203.

The coil controller 1402 issues a target current value to each connected current controller 1403. The current controller 1403 controls the amount of current in the connected coil 202.

Multiple X sensors 101 are communicatively connected to the sensor controller 1404.

The multiple X-sensors 101 are attached to the stator 201 at intervals such that one of them can always measure the position of one of the movers 301 even while the mover 301 is being transported.

The integrated controller 1401 determines current command values to be applied to the multiple coils 202 based on the output from the X sensor 101, and transmits them to the coil controller 1402. The coil controller 1402 issues current value commands to the current controller 1403 based on the current command values from the integrated controller 1401, and executes current control. In this way, the integrated controller 1401 functions as a control device, and controls the transport of the mover 301 along the stator 201.

The position control method of the movable element 301 executed by the integrated controller 1401 will be described below with reference to FIG. 16. FIG. 16 is a schematic diagram showing the control method of the movable element 301 in the conveyance system 1001 according to this embodiment. FIG. 16 shows an outline of the control method of the movable element 301, focusing mainly on the data flow. The integrated controller 1401 executes processing using the movable element position calculation information processing function 1512, the movable element position calculation function 1513, the movable element position control function 1514, and the coil current calculation function 1515, as described below. As a result, the integrated controller 1401 controls the conveyance of the movable element 301 while controlling the position of the movable element 301. Note that instead of the integrated controller 1401, the coil controller 1402 can be configured to execute the same processing as the integrated controller 1401.

First, the mover position calculation information processing function 1512 calculates mover position calculation information 1508 from the measurement values from the multiple X sensors 101 and information 1507 on their mounting positions. Next, the mover position calculation function 1513 calculates the number and positions of the movers 301 on the stator 201 that constitutes the transport path from the mover position calculation information 1508. As a result, the mover position calculation function 1513 updates the mover position information and number information of the mover information 1506, which is information about the movers 301. The mover position information indicates the position of the mover 301 on the stator 201 in the X direction, which is the transport direction. The mover information 1506 is prepared for each mover 301 on the stator 201.

The mover position calculation information processing function 1512 identifies the X sensor 101 that detects the linear scale 304 attached to each mover 301 from the measurement values of the multiple X sensors 101. At this time, a coefficient (W) is calculated based on the sensor installation position information 1507 on the stator 201 of the identified X sensor 101 and the measurement values.

Next, the mover position calculation function 1513 calculates the position information of each mover 301 based on the mover position calculation information 1508, which includes the measurement value of the identified X sensor 101 and the calculated coefficient (W), and the sensor position information 1507, and updates the mover information 1506.

Then, the mover position control function 1514 calculates applied force information 1509 for each mover 301 from the current mover information 1506 including the mover position information and the position target value. The applied force information 1509 is information regarding the magnitude of the force to be applied to each mover 301. The applied force information 1509 is prepared for each mover 301 on the stator 201, for example, as shown as Trq-1, Trq-2, ... in FIG. 16.

Next, the coil current calculation function 1515 determines the current command value 15101 to be applied to each coil 202 based on the applied force information 1509 and the mover information 1506.

In this way, the integrated controller 1401 determines the current command value 15101 by executing processing using the mover position calculation information processing function 1512, the mover position calculation function 1513, the mover position control function 1514, and the coil current calculation function 1515. The integrated controller 1401 transmits the determined current command value 15101 to the coil controller 1402.

Here, the processing by the mover position calculation information processing function 1512 will be explained using FIG. 17. FIG. 17 is a schematic diagram explaining the processing by the mover position calculation information processing function 1512.

In FIG. 17, reference point Oe is the position reference of the stator 201 to which the X sensor 101 is attached. Also, reference point Os is the position reference of the linear scale 304 attached to the mover 301. FIG. 17 shows a case in which two movers 301a and 301b are transported as the mover 301, and four X sensors 101a, 101b, 101c, and 101d are arranged as the X sensor 101. The linear scale 304 is attached along the X direction at the same position of each mover 301a and 301b.

Each of the X sensors 101a to 101d observing the mover 301 calculates a coefficient (W) between 0 and 1 based on the output distances Pa, Pb, Pc, and Pd.

For example, since the X sensors 101a and 101c in FIG. 17 are determined to be present in the sensor information effective area 1510, the following equations (27) and (28) are used for the calculation.
W(101a)=1...Formula (27)
W(101c)=1...Formula (28)

17 is determined to be in a sensor information invalid area 1512a, the calculation is performed as in the following formula (29). The sensor information invalid area 1512 is provided to ignore the output of the X sensor 101 in an area where the detection error of the X sensor 101 is equal to or greater than a certain value, since the X sensor 101 detects the end of the linear scale 304.
W(101b)=0...Formula (29)

17 is determined to be present in the sensor information load region 1511b, a value between 0 and 1 is calculated using a continuous function that monotonically increases and decreases from 0 to 1 or from 1 to 0, such as a sigmoid function as shown in the following formula (30). In formula (30), a is the gain of the sigmoid function.
W(101d)=1/(1+exp(-a*Pd))...Formula (30)

The mover position calculation information processing function 1512 calculates the coefficient (W) based on the output of the X sensor 101 and the sensor installation position information 1507 as described above. It outputs the mover position calculation information 1508 to which the calculated coefficient (W) is added, and uses this as the input of the mover position calculation function 1513.

It is possible to perform processing similar to the mover position calculation information processing function 1512 described above by using another function exemplified in the first embodiment as a function for calculating the coefficient (W) or by storing the coefficient profile in the memory of the integrated controller 1401.

Next, the processing by the mover position calculation function 1513 will be explained using FIG. 17.

For example, one X sensor 101a faces linear scale 304 of mover 301a shown in Fig. 17. X sensor 101a reads linear scale 304 of mover 301a and outputs distance Pa. Furthermore, the position on the X axis of X sensor 101a with reference point Oe as the origin is Sa. Therefore, using the output of X sensor 101a, position Pos(301a, 101a) of mover 301a can be calculated by the following equation (31).
Pos (301a, 101a)=Sa-Pa...Formula (31)

For example, three X-sensors 101b, 101c, and 101d face linear scale 304 of mover 301b shown in Fig. 17. X-sensor 101b reads linear scale 304 of mover 301b and outputs distance Pb. Furthermore, the position on the X-axis of X-sensor 101b with reference point Oe as the origin is Sb. Therefore, the position Pos(301b, 101b) of mover 301b on the X-axis based on the output of X-sensor 101b can be calculated by the following equation (32).
Pos (301b, 101b) = Sb - Pb...Equation (32)

Similarly, X-sensors 101c and 101d read linear scale 304 of mover 301b and output distances Pc and Pd, respectively. Furthermore, the positions on the X-axis of X-sensors 101c and 101d with reference point Oe as the origin are Sc and Sd, respectively. Therefore, positions Pos(301b, 101c) and Pos(301b, 101d) of mover 301b on the X-axis based on the outputs of X-sensors 101c and 101d can be calculated by the following equations (33) and (34).
Pos (301b, 101c) = Sc-Pc...Formula (33)
Pos (301b, 101d) = Sd - Pd...Formula (34)

Here, since the installation positions of each of the X sensors 101b, 101c, and 101d have been accurately measured in advance, the difference between the three values Pos(301b, 101b), Pos(301b, 101c), and Pos(301b, 101d) is sufficiently small relative to the length of the mover 301. In this way, when the difference in the position of the mover 301 on the X axis based on the output of the multiple X sensors 101 is sufficiently small, it can be determined that the multiple X sensors 101 are observing the linear scale 304 of the same mover 301.

Next, the position of the movable element 301 on the X-axis Pos(301, 101) is calculated based on the output of the X-sensor 101 that is determined to be observing the same movable element 301, and the weighted average is calculated based on the movable element position calculation information 1508 to uniquely determine the observed position of the movable element 301.

For example, the position Pos(301a) of the mover 301a shown in FIG. 17 is calculated using the following equation (35).
Pos(301a)=W(101a)*Pos(301a, 101a)/W(101a)...Formula (35)

Alternatively, in terms of calculation error, when there is only one X sensor 101 detecting the same mover 301, the following formula (36) can also be used.
Pos (301a) = Pos (301a, 101a)...Equation (36)

Next, for example, the position Pos(301b) of the mover 301b shown in FIG. 17 is calculated using the following equation (37).
Pos (301b) = {W (101b) * Pos (301b, 101b) + W (101c) * Pos (301b, 101c) +W(101d)*Pos(301b, 101d)}/{W(101b)+W(101c)+W(101d)}...Formula (37)

Next, the mover position control function 1514 calculates applied force information 1509 for each mover 301 from the current mover information 1506 and the target value (command position). The applied force information 1509 is information regarding the magnitude of the force to be applied to each mover 301.

Next, the coil current calculation function 1515 determines the current command value 15101 to be applied to each coil 202 based on the applied force information 1509 and the mover information 1506.

Next, the process performed by the coil current calculation function 1515 will be described with reference to FIG. 20. In the force notation used below, the directions in which the force acts in the X direction and the Y direction are indicated by x and y, respectively.

In FIG. 21(a), the force acting on the permanent magnet 303 is expressed as follows. The force acting on each permanent magnet 303 is an electromagnetic force that the permanent magnet 303 receives from the multiple coils 202 to which a current is applied. The permanent magnet 303 receives an electromagnetic force Fx in the X direction, which is the transport direction of the mover 301, as well as an electromagnetic force Fy in the Y direction, from the multiple coils 202 to which a current is applied.

A method of applying a force in the X direction to a permanent magnet 303 in which S poles and N poles are alternately arranged in the X direction is described below. FIG. 20 is a schematic diagram illustrating a method of applying a force in the X direction to a permanent magnet 303. The coil current calculation function 1515 determines a current command value to be applied to the coil 202 in order to apply a force in the X direction to the permanent magnet 303 according to the following.

Let X be the position of the mover 301, j be the number of the coil 202 in the row, and let Fx(j,X) and Fy(j,X) be the magnitudes of the forces acting in the X and Y directions of coil 202(j) per unit current. Also, let i(j) be the magnitude of the current in coil 202(j). Note that coil 202(j) is the jth coil 202.

The top diagram in FIG. 20 shows nine coils 202 facing a permanent magnet 303, with the X axis running horizontally and the Z axis running vertically. The middle diagram in FIG. 20 is a view of the top diagram in FIG. 20 from the Z direction. The coils 202 are given numbers j from 1 to 6 in the order they are lined up in the X direction, and below each coil 202 will be identified by a notation such as coil 202(1).

As shown in the upper and middle figures in Figure 20, the coils 202 are arranged at a pitch of distance L. On the other hand, the permanent magnets 303 of the mover 301 are arranged at a pitch of distance 3/2*L.

The lower graph in FIG. 20 is a graph that shows a schematic representation of the magnitude of the X-direction force Fx and the Y-direction force Fy that are generated when a unit current is applied to each of the coils 202 shown in the upper and middle diagrams in FIG. 20.

For simplicity, in FIG. 20, the origin Oc of the X-direction position of coil 202 is set as the center of coil 202(5), and the center Om of permanent magnet 303 in the X-direction is set as the origin. Therefore, FIG. 20 shows the case where Oc and Om coincide, that is, X=0.

In this case, for example, the force per unit current acting on coil 202(4) is Fx(4,0) in the X direction and Fy(4,0) in the Y direction. Also, the force per unit current acting on coil 202(5) is Fx(5,0) in the X direction and Fy(5,0) in the Y direction.

Here, the current values applied to coils 202(1) to 202(9) are i(1) to i(9), respectively. Then, the magnitude of force Fx acting in the X direction and the magnitude of force Fy acting in the Y direction on permanent magnet 303 are generally expressed by the following equations (38) and (39), respectively.
Fx=Σ{Fx(j,X)*i(j)}, (j=1,...,9)...Equation (38)
Fy=Σ{Fy(j,X)*i(j)}, (j=1,...,9)...Equation (39)

By determining the current command value so that the current values i(1) to i(9) that satisfy the above expressions (38) and (39) are applied to the coils 202(1) to 202(9), respectively, it is possible to apply forces in the X and Y directions to the permanent magnet 303. The coil current calculation function 1515 can determine the current command value to be applied to the coil 202(j) as described above in order to apply forces in the X and Y directions to the permanent magnet 303.

For simplicity's sake, in the case shown in Figure 20, let us consider an example in which only coils 202(3), 202(4), and 202(5) of coils 202(1) to 202(9) are used for permanent magnet 303, and furthermore, the sum of the current values of these three is controlled to be 0. In this example, force Fx acting in the X direction and force Fy acting in the Y direction on permanent magnet 303 are expressed by the following equations (40) and (41), respectively.
Fx=Fx(3,X)*i(3)+Fx(4,X)*i(4)+Fx(5,X)*i(5)...Formula (40)
Fy=Fy(3,X)*i(3)+Fy(4,X)*i(4)+Fy(5,X)*i(5)...Formula (41)

Moreover, the current values of the coils 202(1) to 202(9) can be set so as to satisfy the following expressions (42) and (43).
i(3)+i(4)+i(5)=0...Equation (42)
i(1)=i(2)=i(6)=i(7)=i(8)=i(9)=0...Formula (43)

21B, the mover 301 is constrained in the Y direction by the guide rail 204, but it is desirable to transport it without applying unnecessary load. Therefore, it is desirable to set the force Fy acting on the permanent magnet 303 in the Y direction so as to satisfy the following formula (44).
Fy=0...Formula (44)

Therefore, when the magnitude of force Fx required for the permanent magnet 303 is determined, the current values i(1) to i(9) can be uniquely determined. A force in the X direction is applied to the mover 301 based on the current command value determined in this way. Due to the force in the X direction applied to the mover 301, the mover 301 obtains a propulsive force for moving in the X direction, and is controlled to be transported in the X direction.

In this way, the integrated controller 1401 controls the current applied to the multiple coils 202, thereby controlling the X-direction force applied to the mover 301.

When the center Oc of the coil 202 moves relative to the center Om of the permanent magnet 303bR due to the movement of the mover 301, that is, when X≠0, the coil 202 according to the moved position can be selected. Furthermore, a calculation similar to that described above can be performed based on the force per unit current generated in the coil 202.

As described above, the integrated controller 1401 controls the position of the mover 301 on the stator 201 by determining and controlling the current command value of the current applied to the multiple coils 202. In other words, the integrated controller 1401 functions as a transport control means that controls the transport of the mover 301, and controls the transport of the mover 301 on the stator 201 by controlling the electromagnetic force that the permanent magnet 303 receives from the multiple coils 202. Note that all or part of the functions of the integrated controller 1401 as a control device can be replaced by the coil controller 1402 or other control devices.

Next, the effects of the present invention will be explained using the example of X-sensor detection shown in Figures 18 and 19.

Figure 18 shows how the linear scale 304 attached to the movable element 301 (not shown) moves as the movable element 301 is transported, and the multiple X-sensors 101a, 101b have different sensor installation positions due to variations in sensor installation accuracy. In Figure 18, the X-sensors 101a', 101b' shown by dashed lines are the installation positions of the X-sensors in the design, and the X-sensors 101a, 101b are a schematic representation of the installation positions of the X-sensors actually installed.

As shown in FIG. 18, as the movable element 301 is transported, the X-sensor 101b starts to detect the linear scale 304 anew. From the viewpoint of suppressing vibration of the movable element 301, it is desirable that the detection position and orientation when the detection sensor is switched be detected without error, regardless of the switching of the X-sensor 101. However, as described above, detection errors occur due to the sensor installation accuracy, machine differences, etc.

In conventional technology, the calculation result of the movable element position information would sometimes fluctuate discontinuously and significantly when the X sensor 101 was switched. In contrast, the calculation result of the movable element position information using the coefficient (W) changes continuously, making it possible to minimize fluctuations in the detection position caused by switching of the X sensor.

The sensors used to calculate the mover information 1506 are successively switched as the mover 301 is transported. At that time, the sensor installation positions change continuously with the coefficient (W) from sensor information invalid area 1512b → sensor information load area 1511b → sensor information valid area 1510A → sensor information load area 1511a → sensor information invalid area 1512a. Therefore, according to this embodiment, it is possible to keep the fluctuation of the detection position when the detection sensor is switched small. Therefore, it is possible to eliminate the vibration of the mover caused by switching of the detection sensor, and stable transport is possible.

In addition, the calculation process of the mover position information of the mover 301 shown by the mover position calculation function 501 in FIG. 4 in the first embodiment can be replaced with the mover position calculation information processing function 1512 and the mover position calculation function 1513 in the second embodiment. As a result, in the calculation process of the mover position information in the first embodiment, the vibration of the mover caused by switching of the detection sensor in the first direction can be removed, as in the second embodiment.

In addition, in this embodiment, the coefficient (W) calculated by the movable element position calculation information processing function 1512 is calculated based on the relative position (calculated from the output and installation position) of the movable element 301 and the X sensor 101, but a method of calculating the coefficient (W) according to the detection time of the X sensor 101 can also be used. With this method shown below, it is possible to eliminate the vibration of the movable element caused by switching of the detection sensor regardless of the moving speed of the movable element 301, and stable transport is possible. Note that information on the relative position of the movable element 301 and the X sensor 101 may be added to this example in which the position information of the movable element is corrected according to the detection time at which the X sensor 101 detects the movable element 301.

For example, the X sensor 101e in FIG. 19 starts detecting the mover 301c at time Ts as the mover 301c is transported, and stops detecting the mover 301c at time Te.

For example, the X sensor 101e in FIG. 19 is determined to have the sensor information invalid time 1522 from time Ts to T1 and from time T4 to Te, and is therefore calculated as in the following formula (45).
W(101e, t)=0, (Ts<t<T1, T4<t<Te)...Equation (45)

Furthermore, for the X sensor 101e in FIG. 19, the period from time T2 to T3 is determined as the sensor information valid time 1520, and therefore calculation is performed as in the following formula (46).
W(101e, t)=1, (T2≦t≦T3)...Formula (46)

19, the time from T1 to T2 and the time from T3 to T4 are determined as the sensor information load time 1521. Therefore, for example, a value between 0 and 1 is calculated using a continuous function that monotonically increases and decreases from 0 to 1 or from 1 to 0, such as a sigmoid function as shown in the following formulas (47) and (48). In formulas (47) and (48), a is the gain of the sigmoid function.
W(101e, t)=1/{1+exp(-a*(t-t1'))}, (T1≦t<T2, t1'=(T2-T1)/2)...Equation (47)
W(101e, t)=1-1/{1+exp(-a*(t-t2'))}, (T3<t≦T4, t2'=(T4-T3)/2)...Equation (48)

The mover position calculation information processing function 1512 may calculate the coefficient (W) based on the detection time of the X sensor 101 as described above. The mover position calculation information 1508 to which the calculated coefficient (W) is added is output and used as an input to the mover position calculation function 1513.

The time Te at which the movable element 301c is no longer detected can be determined according to the movement state of the movable element 301c.

19 is transported at a constant speed Vc, the detection end time Te is determined by the following equation (49): Lc in equation (49) is the length of the linear scale 304 attached to the movable element 301c.
Te=Ts+Lc/Vc...Formula (49)

In addition, if the movable element 301 stops while the X-sensor 101 is detecting the movable element 301, the detection end time Te can be correctly determined by adding the stop time and the acceleration/deceleration time.

By controlling the position of the mover using the mover position calculation information 1508 to which the coefficient (W) calculated in this manner has been added, it is possible to similarly minimize fluctuations in the detection position when the detection sensor is switched.

REFERENCE SIGNS LIST 101 X sensor 102 Y sensor 103 Z sensor 201 stator 202 coil 203 coil unit 301 mover 302 workpiece 303 permanent magnet 304 linear scale 305 Y target 306 Z target

Claims (15)

A mover that moves along a first direction;
a stator having a plurality of first sensors arranged along the first direction and configured to detect position information of the mover;
a control unit that corrects position information of the mover based on a relative position between at least one of the first sensors and the mover obtained from a detection value of the first sensor and/or a detection time at which the first sensor detects the mover, and controls a position and/or an attitude of the mover ,
The control unit corrects the position information of the mover by weighting the detection value of a sensor that detects a position near the center of the mover more heavily than the detection value of a sensor that detects a position outside the center . The conveying device according to claim 1, characterized in that the control unit adjusts at least one of the multiple detection values of the multiple first sensors using a coefficient to correct the position information of the mover. When a detection target area of the mover is set to a first area set in a central portion, a second area set at an end portion in the first direction, and a third area between the first area and the second area,
3. The transport device according to claim 2, wherein the coefficient for the second region and/or the coefficient for the third region is smaller than the coefficient for the first region. The coefficient for the third region is
4. The transport device according to claim 3, wherein the weighting is set to vary between 0 and 1 depending on a relative position between at least one of the plurality of first sensors and the mover. A mover that moves along a first direction;
a stator including a plurality of first sensors arranged along the first direction to detect position information of the mover in the first direction, and a plurality of second sensors to detect position information of the mover in a second direction intersecting the first direction;
a control unit that selects at least one of the plurality of second sensors using detection values of the plurality of first sensors, corrects position information of the mover in a second direction based on a relative position between the selected second sensor and the mover, and controls a position and/or an attitude of the mover ,
The control unit corrects the position information of the mover by weighting the detection value of a sensor that detects a position near the center of the mover more heavily than the detection value of a sensor that detects a position outside the center . The conveying device according to claim 5, characterized in that the control unit adjusts at least one of the multiple detection values of the multiple second sensors using a coefficient to correct the position information of the mover in the second direction. When a detection target area of the mover is set to a first area set in a central portion, a second area set at an end portion in the first direction, and a third area between the first area and the second area,
7. The transport device according to claim 6, wherein the coefficient for the second region and/or the coefficient for the third region is smaller than the coefficient for the first region. The coefficient for the third region is
8. The transport device according to claim 7, wherein the weighting is set to vary between 0 and 1 depending on the relative position between the selected second sensor and the mover. The conveying device according to claim 7 or 8, characterized in that the distance between two adjacent ones of the plurality of second sensors is less than half the length of the movable element in the first direction in the first region. the stator has a plurality of third sensors that detect position information of the mover in a third direction that intersects with the first direction and the second direction;
The conveying device according to any one of claims 5 to 9, characterized in that the control unit selects at least one of the multiple third sensors using detection values of the multiple first sensors, corrects position information of the mover in a third direction based on a relative position between the selected third sensor and the mover, and controls the position and/or attitude of the mover. The conveying device according to claim 10, characterized in that the control unit adjusts at least one of the multiple detection values of the multiple third sensors using a coefficient to correct the position information of the mover in the third direction. the mover has a first magnet group consisting of a plurality of magnets arranged along the first direction, and a second magnet group consisting of a plurality of magnets arranged along a second direction intersecting the first direction,
12. The transport device according to claim 5, wherein the stator has a plurality of coils arranged along the first direction so as to be opposed to the first magnet group and the second magnet group. The conveying device according to claim 12, characterized in that the movement of the mover in the first direction is controlled by the first magnet group and the multiple coils, and the position in a second direction intersecting the first direction is controlled by the second magnet group and the coils. A production system comprising the conveying device according to any one of claims 1 to 13 and a production device that processes a workpiece moved by the conveying device. A method for manufacturing an article, characterized in that the article is manufactured by the production system described in claim 14.

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