Conveying device, control method for conveying device, method for manufacturing articles

Abstract

This technology provides a way to reduce equipment costs and enable high-speed driving while suppressing vibrations of the movable element in straight and curved sections without changing the transport speed. [Solution] The conveying device of the present disclosure comprises a stator having a curved section and a control unit that controls the position and speed of a movable section that moves along a first direction while in contact with the stator, wherein the control unit applies a thrust in a second direction perpendicular to the first direction to the movable section when the movable section moves along the curved section.

Description

Technical Field

[0001] The present disclosure relates to a conveying device, a control method for the conveying device, and a method for manufacturing an article.

Background Art

[0002] Generally, in a manufacturing site for assembling factory-automated industrial products, a conveying system for conveying workpieces such as parts between a plurality of stations is used.

[0003] In recent years, a conveying system has been increasingly used that can perform processing at a station while holding a workpiece on a carriage and then convey the workpiece to the next-station while still held on the carriage. As such a conveying system, a moving magnet type linear motor system (moving magnet type linear motor) has been proposed.

[0004] The moving magnet type linear motor system is composed of a combination of a mover in which a plurality of permanent magnets are mounted on a carriage with N poles and S poles arranged alternately, a stator in which a plurality of coils are arranged in the traveling direction of the carriage, and a current controller for supplying current to the coils. In addition to the advantage that processing can be performed while holding a workpiece on a carriage, this moving magnet type linear motor system can relax the constraints on the conveying path because no wiring is required on the mover side.

[0005] Such a conveying system does not necessarily need to be connected by a straight path between stations and may be connected by a curved path. Also, a return path may be configured so that the carriage that has completed a process can convey the next workpiece. The connection between the forward path and the return path may be configured by a curve.

[0006] In a moving magnet type linear motor system having a straight portion and a curved portion, the control characteristics of the straight portion and the curved portion are generally different and vibration or oscillation may occur because the distance between the coil and the permanent magnet and the pole pitch change in the straight portion and the curved portion.

[0007] In contrast, Patent Document 1 discloses a guide mechanism that drives a curved section while controlling the levitation of the movable element using three coils facing a ferromagnetic rail, based on the displacement of the movable element in the width direction corresponding to the centrifugal force, so that the amount of levitation of the movable element is within a predetermined range. Furthermore, Patent Document 2 discloses a technology that determines the speed based on the dimensions of the conveyed object and the radius of curvature of the curved section, and reduces the speed when traveling on the curved section. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2021-31232 [Patent Document 2] International Publication No. 2019 / 180908 [Overview of the project] [Problems that the invention aims to solve]

[0009] As described in Patent Document 1, placing multiple sensors along the transport path leads to increased equipment costs. Furthermore, it is difficult to accurately detect minute displacements relative to the guide, considering the differences between each movable element and the multiple sensors, as well as variations in their installation positions. Additionally, as described in Patent Document 2, reducing the speed of the movable element during transport affects the cycle time of the equipment.

[0010] This disclosure provides a technology for a movable magnet type linear motor system that enables high-speed driving while suppressing vibration of the movable element in straight and curved sections, without reducing equipment costs or changing the transport speed. [Means for solving the problem]

[0011] The conveying device of this disclosure comprises a stator having a curved section and a control unit that controls the position and speed of a movable section that moves along a first direction while in contact with the stator, wherein the control unit applies a thrust to the movable section in a second direction perpendicular to the first direction when the movable section moves along the curved section. It is characterized by the following. [Effects of the Invention]

[0012] According to this disclosure, a technology is available that enables high-speed driving of a movable magnet type linear motor system while suppressing vibration of the movable element in straight and curved sections, without reducing equipment costs or changing the transport speed. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram of the entire movable magnet type linear motor system according to the first embodiment. [Figure 2] This is a system configuration diagram according to the first embodiment. [Figure 3] This is a schematic diagram showing a movable element according to the first embodiment. [Figure 4] This is a schematic diagram showing the straight and curved sections according to the first embodiment. [Figure 5] This is a schematic diagram showing the straight and curved sections according to the second embodiment. [Figure 6] This is a schematic diagram showing the straight and curved sections according to the third embodiment. [Figure 7] This is a schematic diagram showing the linear section control according to the first embodiment. [Figure 8] This is a schematic diagram showing the curve section control according to the first embodiment. [Figure 9] This is a schematic diagram showing the boundary control between a straight section and a curved section according to the first embodiment. [Figure 10] This is a schematic diagram showing the curve section control according to the second embodiment. [Figure 11] This is a schematic diagram showing the boundary control between a straight section and a curved section according to the second embodiment. [Figure 12] This is a schematic diagram showing the straight and curved sections according to the fourth embodiment. [Figure 13] This is a schematic diagram illustrating the thrust control of the q-axis and d-axis according to the first embodiment. [Modes for carrying out the invention]

[0014] Hereinafter, embodiments for implementing the present disclosure will be described with reference to the accompanying drawings. Note that the embodiments shown below are merely examples, and for example, those skilled in the art can appropriately change the detailed configuration without departing from the spirit of the present disclosure.

[0015] (First Embodiment) FIG. 1 is a schematic diagram showing the overall structure of the moving magnet type linear motor system in the present embodiment.

[0016] The transport system 1, which is a moving magnet type linear motor system in the present embodiment, has a stator 2 and a mover 3. The stator 2 has a linear module 21 and a curved module 22. A plurality of movers 3 driven along a guide (not shown) are arranged on the stator 2. In FIG. 1, a simple annular configuration is shown, but this is not the limit, and it can be composed of a plurality of modules having different lengths and curvatures. Also, although three movers 3 are shown in FIG. 1, the number is not limited to this, and at least one or more movers 3 can be controlled on the stator 2.

[0017] FIG. 2 shows the system configuration of the transport system in the present embodiment. The transport system 1 has a transport controller 12 communicably connected to a higher-level system controller 11 such as a PLC, and a plurality of motor controllers 13 communicably connected to the transport controller 12. A plurality of coils 201 and a plurality of sensors 202 arranged on the stator 2 are connected to the motor controller 13.

[0018] The plurality of coils 201 are arranged at predetermined intervals in the transport direction, which is the first direction. Note that the coil 201 may be a coil with a core or a coreless type coil. The plurality of coils 201 are current-controlled, for example, in units of three. When the coil 201 is energized, an electromagnetic force can be generated between the coil 201 and the permanent magnet 31 of the mover 3 to apply a force to the mover 3.

[0019] The sensor 202 shown in Figure 2 is a sensor that detects the position of the movable element 3 in the transport direction. For example, it detects a linear scale 32 attached to the movable element 3 and functions as a linear encoder to determine the position of the movable element 3 on the transport system.

[0020] Figure 2 shows a configuration in which three coils 201 and three sensors 202 are connected to the motor controller 13, but it is not limited to this configuration. Depending on the configuration of modules 21 and 22, at least one coil 201 and one sensor 202 will be connected to the motor controller 13.

[0021] Figure 3 is a schematic diagram showing a movable element according to this embodiment. A workpiece 4 is loaded onto the movable element 3 and transported on the stator 2. Multiple permanent magnets 31 are arranged on the movable element 3 so as to face the coil 201 along a first direction, and an electromagnetic force can be generated between them and the coil 201 of the stator 2 to apply force to the movable element 3. In Figure 3, a configuration in which five poles with alternating north and south poles are arranged is shown as an example, but this is not the only configuration.

[0022] Furthermore, the position of the movable element 3 in the first direction is determined by detecting the linear scale 32 fixed to the movable element 3 with the sensor 202. In Figure 3, the sliding component 33 is a guide block or roller, etc., that operates along a guide (not shown) fixed on the stator 2. By controlling the current applied to the coil 201, the movable element 3 is driven while sliding along the guide.

[0023] Next, the control unit of the movable magnet type linear motor system in the transport system 1 will be described. As mentioned above, the transport system 1 has a transport controller 12 and motor controllers 13 provided for each module. The transport controller 12 and the multiple motor controllers 13 constitute the control unit 10 of the transport system 1. In addition, the position of the multiple movable elements 3 on the transport system 1, which is the first direction, is determined by a sensor 202 connected to the motor controller 13 shown in Figure 2.

[0024] The transport controller 12, in accordance with the transport command from the system controller 11, identifies one of the multiple motor controllers 13 that can control the movable element 3 to be driven. Here, the motor controller 13 that can control the movable element 3 is the motor controller 13 to which the coil 201 facing the movable element 3 is connected.

[0025] The transport controller 12 notifies the identified motor controller 13 of the drive profile information, such as the commanded position, speed, and acceleration / deceleration of the movable element 3 to be driven.

[0026] The motor controller 13 derives thrust information to be applied to the movable element 3 to be driven, according to the received drive profile information.

[0027] The thrust information consists of a transport direction thrust 40, which is the thrust in the first direction, the transport direction, and a d-axis direction thrust 41, which is the thrust in the second direction perpendicular to the first direction. Generally, the transport direction thrust 40 is derived using the transport direction position information of the movable element 3 by a position controller such as a PID controller. The d-axis direction thrust 41 is generally derived by a position controller such as a PID controller with a command value of 0. The d-axis direction thrust 41 will be described in detail in the descriptions of each embodiment below.

[0028] Furthermore, the motor controller 13 uses thrust information to determine current command values ​​to be applied to the multiple coils 201 connected to the motor controller 13, and by performing current control, it can apply the desired thrust to the permanent magnets 31 of the movable element 3.

[0029] Next, the current command values ​​to be applied to the multiple coils 201 are determined in order to independently apply force to the permanent magnet 31 in the first direction, which is the transport direction, and in the second direction, which is the d-axis direction, perpendicular to the first direction, according to the following. Hereinafter, the first direction will also be referred to as the q-axis direction.

[0030] Here, we will explain the thrust control of the q-axis and d-axis using Figure 13. The upper part of Figure 13 shows the six coils 201 facing the permanent magnet 31, viewed from the d-axis direction, which is the second direction, with the X-axis, which is the first direction, running horizontally. The middle part of Figure 13 shows the upper part of Figure 13 viewed from a direction perpendicular to the first and second directions. The coils 201 are numbered j from 1 to 6 in the order they are arranged in the X-axis direction, and below, each coil 201 will be identified by notation such as coil 201(1).

[0031] As shown in the upper and middle diagrams of Figure 13, the coils 201 are arranged at a pitch of distance L. On the other hand, the permanent magnets 31 of the movable element 3 are arranged at a pitch of distance 3 / 2 × L.

[0032] For simplicity, in Figure 13, the origin Oc of the X-direction position of coil 201 is set to be midway between coil 201(3) and coil 201(4), and the origin is set to the X-direction center Om of the permanent magnet 31. Therefore, Figure 13 shows the case where Oc and Om coincide, i.e., X=0.

[0033] The lower graph in Figure 13 schematically shows the magnitudes of the force Fx in the X direction and the force Fd in the d-axis direction generated when a unit current is applied to each coil 201 in the case of X=0, as shown in the upper and middle figures of Figure 13.

[0034] In this case, for example, the force per unit current acting on coil 201(4) is Fx(4,0) in the X direction and Fd(4,0) in the d-axis direction. Also, the force per unit current acting on coil 201(5) is Fx(5,0) in the X direction and Fd(5,0) in the d-axis direction.

[0035] Here, let i(1) to i(6) be the current values ​​applied to coils 201(1) to 201(6), respectively. Then, the magnitude of the force Fxm acting on the permanent magnet 31 in the X direction and the magnitude of the force Fdm acting in the d-axis direction are generally expressed by the following equations 1 and 2, respectively. [Math 1] Fxm=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,X)×i(6) [Math 2] Fdm=Fd(1,X)×i(1)+Fd(2,X)×i(2)+Fd(3,X)×i(3)+Fd(4,X)×i(4)+Fd(5,X)×i(5)+Fd(6,X)×i(6) By determining the current command values ​​so that current values ​​i(1) to (6) satisfying equations 1 and 2 above are applied to coils 201(1) to 201(6), respectively, forces can be applied to the permanent magnet 31 independently in the X direction and the d direction. The motor controller 13 can determine the current command value to be applied to coil 201(j) as described above.

[0036] Here, in the case shown in Figure 13, we consider the case where only coils 201(3), 201(4), and 201(5) from coils 201(1) to coil(6) are used with respect to the permanent magnet 31, and furthermore, the sum of the current values ​​of these three coils is controlled to be 0. In this case, the force Fxm acting on the permanent magnet 31 in the X direction and the force Fdm acting in the d-axis direction are expressed by the following equations 3 and 4, respectively. [Math 3] Fxm=Fx(3,X)×i(3)+Fx(4,X)×i(4)+Fx(5,X)×i(5) [Math 4] Fdm=Fd(3,X)×i(3)+Fd(4,X)×i(4)+Fd(5,X)×i(5)

[0037] Furthermore, the current values ​​of coils 201(1) to 201(6) can be set to satisfy equations 5 and 6 below. [Math 5] i(3)+i(4)+i(5)=0 [Math 6] i(1)=i(2)=i(6)=0 Therefore, once the required force (Fxm, Fdm) for the permanent magnet 31 is determined, the current values ​​i(1) to i(6) can be uniquely determined. Based on the current command values ​​thus determined, forces are applied to the movable element 3 in the X direction and the d direction. The force applied to the movable element 3 in the X direction provides the movable element 3 with a propulsive force that moves it in the X direction, and it moves in the X direction. Furthermore, according to this embodiment, the force applied to the movable element 3 in the d direction controls the contact state of the sliding part 33 between the stator 2 and the movable element 3.

[0038] In this way, the transport controller 12 and the motor controller 13 control the force applied to the movable element 3 by controlling the current applied to the multiple coils 201.

[0039] Furthermore, if the center Oc of the coil 201 moves relative to the center Om of the permanent magnet 31 due to the driving of the movable element 3, i.e., when X≠0, the coil 201 can be selected according to the moved position. In addition, the same calculation as above can be performed based on the force per unit current generated in the coil 201.

[0040] As described above, the transport system 1 controls the transport operation of the movable element 3 on the stator 2 by determining and controlling the current command values ​​of the currents applied to the multiple coils 201. Note that some of the functions of the motor controller 13, which acts as a control device, can be replaced by the transport controller 12 or other control devices.

[0041] Next, the driving method in the first embodiment will be described using Figures 4 and 7 to 9. Figure 4 shows the arrangement of the coil and permanent magnet in the first embodiment. The movable elements 3a and 3b are arranged on the straight section guide 210 and the curved section guide 220 on the stator 2 (not shown), and the curved section has a so-called outer rotor configuration in which the coil 201 is arranged radially inward. The movable element 3 has a front outer roller 33fo, a front inner roller 33fi, a rear outer roller 33bo, and a rear inner roller 33bi arranged as sliding parts 33 with respect to the guides.

[0042] Figure 7 shows the state in which the movable element 3a is driven on the linear module 21 as the first embodiment. Here, the first direction, which is the transport direction, is defined as the X direction, and the second direction perpendicular to the first direction is defined as the Y direction. The Y direction is the direction of the gap between the coil 201 (not shown) and the permanent magnet 31. Hereafter, the first direction will also be referred to as the q-axis direction, and the second direction as the d-axis direction.

[0043] Figure 7(a) shows the forces acting on the movable element 3a in the conventional system. The movable element 3a is subjected to an attractive force 42 acting between a coil 201 (not shown) and a permanent magnet 31, a transport direction thrust 40 acting in the first direction controlled by the controller, and a contact force 43 acting between the linear section guide 210 and the sliding part 33. Therefore, since the thrust in the d-axis direction is controlled to be 0, the attractive force 42 and the contact force 43 are balanced, and the movable element 3a is transported in the first direction while being restricted by the guide.

[0044] Figure 7(b) shows the forces acting on the movable element 3a in the first embodiment. In addition to the forces shown in Figure 7(a), a thrust force 41 in the d-axis direction, which is a second direction, is applied to the movable element 3a. The d-axis thrust force 41 can be applied as a thrust in the opposite direction to the attractive force 42 to reduce the contact force 43. In Figure 7(b), the contact forces 43bo and 43fo, shown by dashed lines in the figure, are reduced to 43bo' and 43fo', shown by solid lines, by the d-axis thrust force 41.

[0045] Next, we will explain how to determine the d-axis thrust 41 on the linear module 21.

[0046] As mentioned above, the movable element 3a is subjected to an attractive force 42 and a contact force 43 as forces in the second direction. The magnitude of the attractive force 42 depends on the gap between the coil 201 and the permanent magnet 31. Therefore, for example, the attractive force information can be stored in the transport controller 12 or the motor controller 13, and the magnitude Fmag of the attractive force 42, which is the attractive force information, can be used to determine FdRef as the thrust force 41 in the d-axis direction using the following equation 7.

[0047] [Equation 7] FdRef = -Gain × Fmag Here, Gain is the efficiency of the d-axis thrust 41 with respect to the suction force 42. For example, if Gain = 1, a force of the same magnitude and opposite to the suction force 42 is applied to the movable element 3 as a d-axis thrust. Therefore, the contact force 43 can be made approximately 0. Thus, by determining the d-axis thrust 41 using equation (7), it is possible to control the contact force 43. In other words, the contact state between the stator 2 and the movable element 3a can be controlled.

[0048] By using the d-axis thrust 41 and the transport direction thrust 40 together as thrust information, current control is possible in the same manner as in equations 1 to 6 described above. Therefore, the desired transport direction thrust 40 and d-axis thrust 41 can be applied to the movable element 3 on the linear module 21.

[0049] As attractive force information, the design value derived from the gap between the coil 201 and the permanent magnet 31 in the linear module 21 may be stored, or the value measured using a force gauge or the like during startup adjustment may be stored.

[0050] Furthermore, although the above example describes setting Gain=1 and the contact force 43 to 0, this is not the only option. It is desirable to set the contact force 43 so that the change in contact force 43 is small, taking into account the configuration of adjacent modules.

[0051] Next, using Figure 8, the control method on the curve module 22 in the first embodiment will be described.

[0052] Here, the first direction is defined as the X direction, which is the transport direction, and the second direction, which is perpendicular to the first direction, is defined as the Y direction. Here, the first direction is the tangential direction of the curved module 22, and the second direction corresponds to the radial direction of the curved module 22.

[0053] Figures 8(a) and 8(b) show the forces acting on the movable element 3b in the conventional system. The movable element 3b is subjected to an attractive force 42, a transport direction thrust 40 acting in the first direction, and a contact force 43 acting between the curved section guide 220 and the sliding part 33, similar to the control on the linear module 21 described above. In addition, a centrifugal force 44 acts on the movable element 3b depending on its driving state.

[0054] Here, Figure 8(a) shows the force acting on the movable element 3b during low-speed driving, and Figure 8(b) shows the force acting on the movable element 3b during high-speed driving. Due to the action of centrifugal force 44, the contact state between the movable element 3b and the curved section guide 220 changes, and the direction of the contact force 43 and the contact location differ between Figures 8(a) and (b).

[0055] Figures 8(c) and 8(d) show the forces acting on the movable element 3b in the first embodiment. In addition to the forces shown in Figures 8(a) and 8(b), a thrust force 41 in the d-axis direction, which is a second direction, is applied to the movable element 3b. By applying the thrust force 41 in the d-axis direction, it is possible to reduce the contact force 43. In Figure 8(d), the contact forces 43bi and 43fi, shown by the dashed lines in the figure, are reduced to 43bi' and 43fi', shown by the solid lines, by the thrust force 41 in the d-axis direction.

[0056] Next, we will explain how to determine the d-axis thrust 41 on the curve module 22.

[0057] As mentioned above, the movable element 3b is subjected to a second force: an attractive force 42, a contact force 43, and a centrifugal force 44. Similar to the case on the linear module 21 described above, for example, the transport controller 12 or motor controller 13 holds the attractive force information, and the magnitude of the attractive force 42 is taken as Fmag. If the magnitude of the centrifugal force 44 is Fc, then the d-axis thrust 41, FdRef, can be determined as shown in equation 8 below.

[0058] [Math 8] FdRef = -Gain × (Fmag - Fc) Here, Gain is the efficiency of the d-axis thrust 41 with respect to the resultant force of the attractive force 42 and the centrifugal force 44. For example, if Gain = 1, a force of the same magnitude and in the opposite direction to the resultant force of the attractive force 42 and the centrifugal force 44 is applied to the movable element 3 as the d-axis thrust. Therefore, the contact force 43 can be made approximately 0. Thus, by determining the d-axis thrust 41 using equation 8, it is possible to control the contact force 43. In other words, the contact state between the stator 2 and the movable element 3b can be controlled.

[0059] Here, the magnitude Fc of the centrifugal force 44 is a quantity that depends on the velocity Vel, acceleration / deceleration Acc, and / or position X of the movable element 3b, and the curvature C(X) of the curve module 22 at the position of the movable element 3b.

[0060] For simplicity, if we consider the case where the movable element 3b is driven at a constant speed on the curved module 22, the centrifugal force Fc can be expressed by the following equation 9, using the mass m of the movable element 3b.

[0061] [Number 9] Fc=-m×(Vel^2)×C(X) The curvature is stored as curve module information in the transport controller 12 or motor controller 13. The curvature may be the design value of the guide 220, or a value measured during startup adjustment may be used. Based on the above, the d-axis thrust 41 can be determined using equations 8 and 9.

[0062] The d-axis thrust 41 and the transport direction thrust 40 are combined as thrust information, and current control is possible using the equations 1 to 6 mentioned above. Therefore, the desired transport direction thrust 40 and d-axis thrust 41 can be applied to the movable element 3 on the linear module 21.

[0063] Furthermore, as with the control on the linear module 21 described above, the example of setting Gain=1 and the contact force 43 to 0 was explained above, but this is not the only option. It is desirable to set the contact force 43 so that the change in contact force 43 is small, depending on the configuration of adjacent modules.

[0064] Next, using Figure 9, the control method at the boundary between the linear module 21 and the curved module 22 in the first embodiment will be described. Here, as before, the first direction is defined as the X direction as the transport direction, and the second direction perpendicular to the first direction is defined as the Y direction.

[0065] Figures 9(a) and 9(b) show the forces acting on the movable element 3c in the conventional system. The movable element 3c is subjected to an attractive force 42, a transport direction thrust 40, a contact force 43, and a centrifugal force 44, similar to the control method for the curve module 22 described above. Here, Figure 9(a) shows an example during low-speed driving, and Figure 9(b) shows an example during high-speed driving.

[0066] Figures 9(c) to 9(f) show the forces acting on the movable element 3c in the first embodiment. In addition to the forces shown in Figures 9(a) and 9(b), a thrust force 41 in the d-axis direction, which is a second direction, is applied to the movable element 3c. By applying the thrust force 41 in the d-axis direction, it is possible to reduce the contact force 43. Figures 9(c) and 9(d), and Figures 9(e) and 9(f) show two examples with different methods of applying the thrust force 41 in the d-axis direction.

[0067] Next, we will explain how to determine the d-axis thrust 41 at the boundary between the linear module 21 and the curved module 22.

[0068] As described above, the movable element 3c is subjected to an attractive force 42, a contact force 43, and a centrifugal force 44. Similar to the case on the curve module 22 described above, the attractive force information and curve module information are held, for example, in the transport controller 12 or motor controller 13. Using the magnitude Fmag of the attractive force 42 in the attractive force information and the magnitude Fc of the centrifugal force 44 derived from the curve module information and the drive profile of the movable element 3c, FdRef can be determined as the d-axis thrust 41 in the same manner as in Equations 8 and 9.

[0069] By determining the d-axis direction thrust 41 as described above, it is possible to control the contact force 43 on the mover 3c as shown in FIGS. 9(e) and 9(f). That is, the contact state between the stator 2 and the mover 3b can be controlled. In FIGS. 9(e) and 9(f), the contact forces 43bo and 43fi indicated by the broken lines in the figure become the contact forces 43bo' and 43fi' indicated by the solid lines in the figure due to the d-axis direction thrust 41.

[0070] Furthermore, for example, consider determining the d-axis direction thrust 41 determined as described above and applying an inclination in the front and rear along the first direction of the mover 3c to determine the current command value. Let the component of the d-axis direction thrust 41 applied to the positive half (front part) of the first direction of the mover 3c be FdRef_f, and the component of the d-axis direction thrust 41 applied to the negative half (rear part) of the first direction of the mover 3c be FdRef_b.

[0071] For example, they are represented by the following Equation 10 and Equation 11. [Equation 10] FdRef_f = Ratio × FdRef [Equation 11] FdRef_b = (1 - Ratio) × FdRef In Equation 10 and Equation 11, Ratio is the distribution ratio of the d-axis direction thrust 41. However, Ratio is not limited to a value between 0 and 1. For example, if a value exceeding 1 is set, it can be distributed as shown in FIG. 9(c), and if a value between 0 and 1 is set, the d-axis direction thrust 41 can be distributed as shown in FIG. 9(d).

[0072] Also, as shown in FIGS. 9(a) and 9(b), since the magnitude of the centrifugal force 44 acting on the mover 3c changes according to the drive profile of the mover 3c, the contact state is different. Therefore, for example, it may be set as a function Ratio(X, Vel, Acc) according to the drive profile such that Ratio ≧ 1 during low-speed driving and 0 < Ratio < 1 during high-speed driving.

[0073] The magnitude of the d-axis thrust 41 is determined using equations 10 and 11. Here, for example, if we consider that FdRef_b is applied by the current output of coils 201(1) to 201(3) and FdRef_f is applied by the current output of coils 201(4) to 201(6) in the positional relationship shown in Figure 13 above, then it can be expressed as shown in equations 12 and 13 below. [Math 12] Fdm_f=Fd(1,X)×i(1)+Fd(2,X)×i(2)+Fd(3,X)×i(3) [Math 13] Fdm_b=Fd(4,X)×i(4)+Fd(5,X)×i(5)+Fd(6,X)×i(6) Therefore, as described above, the command current value for each coil 201 can be uniquely determined, as previously mentioned. Thus, the contact force 43 of the movable element 3c can be controlled as shown in Figures 9(c) and 9(d). In Figure 9(c), the contact forces 43bo and 43fi, shown by the dashed lines in the figure, become the contact forces 43bo' and 43fi', shown by the solid lines in the figure, due to the d-axis thrust 41. Also, in Figure 9(d), the contact forces 43bi and 43fi, shown by the dashed lines in the figure, change to the contact forces 43bo' and 43fi', shown by the solid lines in the figure, due to the d-axis thrust 41.

[0074] By the method described above, the contact state between the stator 2 and the movable element 3b can be controlled by applying a d-axis thrust 41 to the movable element 3 based on the suction force 42, the curvature of the curve module 22, and the drive profile of the movable element 3. In other words, the d-axis thrust 41 is determined based on the external forces applied to the movable element 3. These external forces include the suction force 42 mentioned above, as well as the centrifugal force 44 generated when the movable element 3 is driven.

[0075] In the above description, the control of the movable element 3 in the transport system 1 was explained. Compared to the conventional method, in the first embodiment, changes in the contact force 43 can be suppressed by the action of the d-axis thrust 41. In other words, the generation of vibrations and abnormal noises caused by changes in the contact state between the stator 2 and the sliding part 33 can be suppressed.

[0076] Therefore, the movable element 3 can be driven at high speed even in the curved module 22 without reducing the transport speed.

[0077] (Second embodiment) Next, the driving method in the second embodiment will be described using Figures 5, 10, and 11. Figure 5 shows the arrangement of the coil and permanent magnet in the second embodiment. The movable elements 3a and 3b are arranged on the straight section guide 210 and the curved section guide 220 on the stator 2 (not shown), and the curved section has a so-called inner rotor configuration in which the coil 201 is arranged radially outward. The movable element 3 has a front outer roller 33fo, a front inner roller 33fi, a rear outer roller 33bo, and a rear inner roller 33bi arranged as sliding parts 33 with respect to the guides.

[0078] Using Figure 10, the control method on the curve module 22 in the second embodiment will be explained. Here, the first direction is defined as the X direction as the transport direction, and the second direction perpendicular to the first direction is defined as the Y direction. Here, the first direction is the tangential direction of the curve module 22, and the second direction corresponds to the radial direction of the curve module 22.

[0079] Figures 10(a) and (b) show the forces acting on the movable element 3b in the conventional system. The movable element 3b is subjected to an attractive force 42, a transport direction thrust 40 acting in the first direction, and a contact force 43 acting between the curved section guide 220 and the sliding part 33, similar to the control on the linear module 21 described above. In addition, a centrifugal force 44 acts on it depending on the driving state of the movable element 3b. Here, Figure 10(a) shows the forces acting on the movable element 3b during low-speed driving, and Figure 10(b) shows the forces acting on the movable element 3b during high-speed driving.

[0080] Here, due to the action of centrifugal force 44, the contact state between the movable element 3b and the curved section guide 220 changes, and the direction of the contact force 43 and the contact location are different in Figures 10(a) and (b).

[0081] Figures 10(c) and (d) show the forces acting on the movable element 3b in the second embodiment. In addition to the forces shown in Figures 10(a) and (b), a thrust force 41 in the d-axis direction, which is a second direction, is applied to the movable element 3b. By applying the thrust force 41 in the d-axis direction, it is possible to reduce the contact force 43. In Figures 10(c) and 10(d), the contact forces 43bo and 43fi, shown by dashed lines in the figures, become the contact forces 43bo' and 43fi', shown by solid lines in the figures, due to the thrust force 41 in the d-axis direction.

[0082] In the control on the curve module 22 of the second embodiment, the only difference compared to the first embodiment is the direction of the attractive force 42 acting on the movable element 3. Therefore, the magnitude of the d-axis thrust 41 can be determined by calculation in the same manner as in equations 8 and 9.

[0083] Therefore, the contact state between the stator 2 and the movable element 3b can be controlled by applying a d-axis thrust 41 to the movable element 3 based on the suction force, the curvature of the curved module 22, and the drive profile of the movable element 3.

[0084] Next, using Figure 11, the control method at the boundary between the linear module 21 and the curved module 22 in the second embodiment will be described. Here, as before, the first direction is defined as the X direction as the transport direction, and the second direction perpendicular to the first direction is defined as the Y direction.

[0085] Figures 11(a) and (b) show the forces acting on the movable element 3c in the conventional system.

[0086] The movable element 3c is subjected to a suction force 42, a transport direction thrust 40, a contact force 43, and a centrifugal force 44, similar to the control method described in the curve module 22 above. Here, Figure 11(a) shows an example of low-speed driving, and Figure 11(b) shows an example of high-speed driving.

[0087] Figures 11(c) to 11(f) show the forces acting on the movable element 3c in the second embodiment.

[0088] In addition to the forces shown in Figures 11(a) and (b), a thrust force 41 in the d-axis direction, which is a second direction, is applied to the movable element 3c. By applying the thrust force 41 in the d-axis direction, it is possible to reduce the contact force 43. Figures 11(c) and (d), and Figures 9(e) and (f) show two examples of different methods for applying the thrust force 41 in the d-axis direction.

[0089] In the control of the boundary between the linear module 21 and the curved module 22 in the second embodiment, the only difference compared to the first embodiment is the direction of the attractive force 42 acting on the movable element 3. Therefore, the magnitude of the d-axis thrust 41 can be determined by calculation in the same manner as in equations 8 to 13.

[0090] In Figures 11(c) to (f), the contact forces 43bi and 43fi, shown by the dashed lines in the figure, become contact forces 43bi' and 43fi', shown by the solid lines in the figure, due to the d-axis thrust 41.

[0091] Therefore, the contact state between the stator 2 and the movable element 3b can be controlled by applying a d-axis thrust 41 to the movable element 3 based on the suction force, the curvature of the curved module 22, and the drive profile of the movable element 3.

[0092] The control of the movable element 3 in the transport system 1 has been described above. Compared to the conventional method, in the second embodiment, changes in the contact force 43 can be suppressed by the action of the d-axis thrust 41. In other words, the generation of vibrations and abnormal noises caused by changes in the contact state between the stator 2 and the sliding part 33 can be suppressed.

[0093] Therefore, the movable element 3 can be driven at high speed even in the curved module 22 without reducing the transport speed.

[0094] Furthermore, although the first and second embodiments were described separately in the above explanation, the configurations of both embodiments may be mixed depending on the configuration of the curve module 22 of the transport system 1. That is, in the curved section, modules in which the permanent magnet 31 is positioned outside the diameter of the coil 201 and modules in which it is positioned inside the diameter may be mixed. In that case as well, as described above, by applying a thrust in the d-axis direction, changes in the contact force 43 can be suppressed, and the system can be driven at high speed even in the curved section.

[0095] (Third embodiment) Next, the driving method in the third embodiment will be described. Figure 6 shows the arrangement of the coil and permanent magnet in the third embodiment. Permanent magnets 31a and 31b, which are placed on movable elements 3a and 3b (not shown), are arranged between the coil 201 placed on the stator 2. In this configuration, the attractive force 42 acting on the movable element 3 is designed to be approximately zero.

[0096] Therefore, the influence of the suction force 42 in the first and second embodiments described above can be ignored. Consequently, the contact state between the stator 2 and the sliding component 33 is easily changed by the drive profile, which contains information on the speed, acceleration, deceleration, and position of the movable element 3.

[0097] In this embodiment as well, similar to the first and second embodiments described above, by applying a d-axis thrust 41 to the movable element 3, the change in contact force 43 can be reduced, and high-speed driving is possible even in curved sections.

[0098] Furthermore, in this embodiment, since the effect of the suction force 42 can be ignored, the effect of the d-axis thrust 41 is greater than in the first and second embodiments.

[0099] (Fourth embodiment) Next, the driving method in the fourth embodiment will be described. The fourth embodiment is an example consisting of a vertical transport system. In this system, since a part of the straight section and / or curved section extends on the vertical plane, gravity acts as the force in the first and second directions of the movable element 3.

[0100] Figure 12 shows the arrangement of the coil and permanent magnet in the fourth embodiment and the force acting on the movable element 3. Here, the first direction is defined as the q-axis, which is the transport direction, and the second direction perpendicular to the first direction is defined as the d-axis. Here, the first direction is the tangential direction of the curved module 22, and the second direction corresponds to the radial direction of the curved module 22.

[0101] Figure 12(a) shows the forces acting on the movable elements 3a to 3c in the conventional system. Movable element 3a is shown in the controlled state in the linear module 21, while movable elements 3b and 3c are shown in the controlled state in the curved module 22. Movable element 3b is an example of low-speed driving, and movable element 3c is an example of high-speed driving.

[0102] The movable element 3a is subjected to a suction force 42, a thrust force 40 in the transport direction, a contact force 43 between the straight section guide 210 and the sliding part 33, and gravity 45.

[0103] In addition to the force acting on the movable element 3a, a centrifugal force 44 also acts on the movable elements 3b and 3c. Here, 45q is the gravitational component acting in the first direction, the q-axis direction, and 45d is the gravitational component acting in the second direction, the d-axis direction.

[0104] Figure 12(b) shows the forces acting on the movable elements 3d to 3f in the fourth embodiment. Movable element 3d is shown in its controlled state on the linear module 21, while movable elements 3e and 3f are shown in their controlled states on the curved module 22. Movable element 3e is an example of low-speed driving, and movable element 3f is an example of high-speed driving.

[0105] In addition to the force acting on the conventional movable element 3a described above, a d-axis thrust 41 is applied to the movable element 3d. Similarly, in the movable elements 3e and 3f, in addition to the force acting on the conventional movable elements 3b and 3c described above, a d-axis thrust 41 is applied.

[0106] First, we will explain how to determine the d-axis thrust 41 on the linear module 21.

[0107] As mentioned above, the movable element 3d is subjected to a second force: an attractive force 42, a contact force 43, and gravity 45. In Figure 12(b), the linear module 21 is arranged such that the first direction is horizontal. Therefore, the transport direction component Fmg_q and the d-axis direction component Fmg_d of gravity 45 are expressed in the following equations 14 and 15, using the magnitude Fmg of gravity 45. [Equation 14] Fmg_q=0 [Number 15] Fmg_d=Fmg Therefore, using equations 14 and 15, and the magnitude Fmag of the suction force 42, FdRef can be determined as the d-axis thrust 41 as shown in equation 16 below. [Math 16] FdRef=-Gain×(-Fmag-Fmg_d)=-Gain×(-Fmag-Fmg)

[0108] Here, Gain is the efficiency of the d-axis thrust 41 with respect to the resultant force of the d-axis components of the attractive force 42 and gravity 45. For example, if Gain = 1, a force of the same magnitude and opposite to the resultant force of the d-axis components of the attractive force 42 and gravity 45 is applied to the movable element 3 as the d-axis thrust. Therefore, the contact force 43 can be made approximately 0. Thus, by determining the d-axis thrust 41 using equation 16, it is possible to control the contact force 43. In other words, the contact state between the stator 2 and the movable element 3d can be controlled.

[0109] In Figure 12(b), the contact forces 43bo and 43fo acting on the movable element 3d, shown by dashed lines in the figure, become contact forces 43bo' and 43fo', shown by solid lines in the figure, due to the thrust force 41 in the d-axis direction.

[0110] Furthermore, while the example shown for the movable element 3d illustrates that the direction in which gravity 45 acts is in the negative direction of the d axis, the direction in which gravity 45 acts can be in the positive direction of the d axis depending on the arrangement of the curved module 22, for example, when controlling the movable element 3f below the Z axis on a linear module 21 (not shown) that is the destination of transport. In other words, equation 15 becomes Fmg_d = -Fmg. In that case as well, the thrust 41 in the d axis direction can be determined and the contact state of the movable element 3 can be controlled, as described above.

[0111] Furthermore, although we considered a configuration in which the linear module 21 is extended horizontally, this is not limited to that configuration. Even in configurations where the module is installed vertically or at an angle, the magnitude of the d-axis thrust 41 can be similarly determined by decomposing the gravity 45 into its q-axis and d-axis components, similar to equations 14 and 15.

[0112] By using the aforementioned d-axis thrust 41 and transport direction thrust 40 together as thrust information, current control is possible using the same calculations as in Equations 1 to 6 described above. Therefore, in the fourth embodiment as well, the desired transport direction thrust 40 and d-axis thrust 41 can be applied to the movable element 3 on the linear module 21.

[0113] Next, we will explain how to determine the d-axis thrust 41 on the curve module 22.

[0114] As described above, the movable elements 3e and 3f are subjected to attractive force 42, contact force 43, and the d-axis component of gravity 45 as forces in the d-axis direction. In Figure 12(b), the transport direction component Fmg_q and the d-axis component Fmg_d of gravity 45 are expressed in the following equations 17 and 18, using the position X of the movable elements 3e and 3f on the curve module and the magnitude Fmg of gravity 45. [Math 17] Fmg_q = Fmg × cos(Theta(X)) [Math 18] Fmg_d = Fmg × sin(Theta(X)) Here, Theta(X) is the angle of the movable element 3, determined by the position X of the movable elements 3e and 3f on the curve module 22. This is stored as curve module information in the transport controller 12 or motor controller 13.

[0115] Therefore, using equations 17 and 18, the magnitude of the attractive force 42 Fmag, and the magnitude of the centrifugal force 44 Fc, the d-axis thrust 41 FdRef can be determined as shown in equation 19 below. [Math 19] FdRef=-Gain×(-Fmag-Fmg_d+Fc) Here, Gain is the efficiency of the d-axis thrust 41 with respect to the resultant force of the d-axis components of the attractive force 42, centrifugal force 44, and gravity 45. For example, if Gain = 1, a force of the same magnitude and in the opposite direction to the resultant force of the d-axis components of the attractive force 42, centrifugal force 44, and gravity 45 is applied to the movable element 3 as the d-axis thrust. Therefore, the contact force 43 can be made approximately 0.

[0116] Furthermore, the magnitude Fc of the centrifugal force 44 is a quantity that depends on the velocity Vel, acceleration / deceleration Acc, and / or position X of the movable element 3b, and the curvature C(X) of the curve module 22 at the position of the movable element 3b.

[0117] For simplicity, if we consider the case where the movable elements 3e and 3f are driven at a constant speed on the curved module 22, the centrifugal force Fc can be expressed using the mass m of the movable elements 3e and 3f as shown in equation 20 below. [Math 20] Fc=-m×(Vel^2)×C(X)

[0118] Therefore, by determining the d-axis thrust 41 using equations 17 to 20, it is possible to control the contact force 43. In other words, the contact state between the stator 2 and the movable elements 3e and 3f can be controlled.

[0119] In Figure 12(b), the contact forces 43bi and 43fi, shown as dashed lines in the figure, acting on the movable elements 3e and 3f become contact forces 43bi' and 43fi', shown as solid lines in the figure, due to the d-axis thrust force 41.

[0120] In the above description, the control of the movable element 3 in the fourth embodiment was explained. Compared to the conventional method, in the fourth embodiment, changes in the contact force 43 can be suppressed by the action of the d-axis thrust 41. In other words, the generation of vibrations and abnormal noises caused by changes in the contact state between the stator 2 and the sliding part 33 can be suppressed.

[0121] Therefore, the movable element 3 can be driven at high speed even in the curved module 22 without reducing the transport speed.

[0122] Based on the above, in the movable magnet type linear motor system, the contact state between the stator 2 and the movable element 3 can be controlled by applying a d-axis thrust 41 to the movable element 3 as a force in a second direction perpendicular to the first direction which is the transport direction. In other words, the generation of vibrations and abnormal noises caused by changes in the contact state between the stator 2 and the movable element 3 can be suppressed in the entire transport system.

[0123] Therefore, according to this embodiment, the curved module 22 can be driven at high speed without reducing the transport speed. Furthermore, since position information in the second direction is not used, there is no need to add additional sensors.

[0124] (Other embodiments) The transport system 1 described herein can be used in a manufacturing system for producing electronic equipment and other articles, as a transport system that carries a workpiece 4, which will become an article, to the work area of ​​each process device, such as a machine tool, by mounting the workpiece 4 on a movable element 3. The process device that performs the work process may be any device that performs any processing on the workpiece, such as a device that assembles parts or a device that paints. Furthermore, the article to be manufactured is not limited to a specific item, but may be any part.

[0125] Thus, using the transport system according to the present invention, a workpiece can be transported to a work area, and a work process can be performed on the workpiece transported to the work area to manufacture an article.

[0126] Furthermore, the effects described in each embodiment are merely a list of the most preferred effects resulting from the technology of this disclosure, and the effects of the technology of this disclosure are not limited to those described above.

[0127] This embodiment includes the following configuration.

[0128] (Item 1) A stator having a curved section, The system includes a control unit that controls the position and speed of a movable element that moves along a first direction while in contact with the stator, The control unit applies a thrust to the movable element in a second direction perpendicular to the first direction when the movable element moves along the curved section. A conveying device characterized by the following features.

[0129] (Item 2) The control unit determines the magnitude of the thrust in the second direction based on the magnitude of the external force acting on the movable element in the second direction. The conveying device according to item 1, characterized by the features described above.

[0130] (Item 3) The conveying device according to item 2, characterized in that the external force is a centrifugal force acting on the movable element.

[0131] (Item 4) The conveying device according to item 3, characterized in that the control unit derives the magnitude of the centrifugal force based on the drive profile of the movable element.

[0132] (Item 5) The stator has a coil, The control unit determines the magnitude of the thrust in the second direction based on the magnitude of the attractive force acting between the coil and the permanent magnet of the movable element. The conveying device according to item 2, characterized in that it is a conveying device.

[0133] (Item 6) The control unit distributes and applies the thrust in the second direction to the front and rear portions of the movable element along the first direction. The conveying device according to item 1, characterized by the features described above.

[0134] (Item 7) The control unit determines the distribution ratio between the front and rear portions in the distribution based on the drive profile of the movable element. The conveying device according to item 6, characterized in that it is a conveying device.

[0135] (Item 8) The stator is, at least a portion of which is extended in a vertical plane, The control unit determines the magnitude of the thrust in the second direction based on the magnitude of the component of gravity acting on the movable element in the second direction. The conveying device according to item 2, characterized in that it is a conveying device.

[0136] (Item 9) The stator has a straight section and a curved section. The control unit determines the magnitude of the thrust in the second direction such that the change in the contact force of the movable element in the straight section and the contact force in the curved section is minimized at the boundary between the adjacent straight section and the curved section. A conveying device according to any one of items 1 to 8, characterized by the above.

[0137] (Item 10) A control method for a conveying device having a stator having a curved section and a control unit that controls the position and speed of a movable element that moves along a first direction while in contact with the stator, When the movable element moves along the curved section, a step is performed to apply a thrust to the movable element in a second direction perpendicular to the first direction. A control method characterized by the following:

[0138] (Item 11) In the above step, the magnitude of the thrust in the second direction is determined based on the magnitude of the external force acting on the movable element in the second direction. The control method according to item 10, characterized by the following:

[0139] (Item 12) The control method according to item 11, characterized in that the external force is a centrifugal force acting on the movable element.

[0140] (Item 13) The control method according to item 12, characterized in that the centrifugal force is derived based on the drive profile of the movable element.

[0141] (Item 14) In the above step, the magnitude of the thrust in the second direction is determined based on the magnitude of the attractive force acting between the coil as the stator and the permanent magnet as the movable element. The control method according to item 11, characterized by the following:

[0142] (Item 15) In the above process, the thrust in the second direction is distributed and applied to the front and rear portions of the movable element along the first direction. The control method according to item 10, characterized by the following:

[0143] (Item 16) The distribution ratio between the front and rear portions in the distribution is determined by the drive profile of the movable element. The control method according to item 15, characterized by the following:

[0144] (Item 17) If at least a portion of the stator is extended in a vertical plane, the magnitude of the thrust in the second direction is determined in the step based on the magnitude of the component of gravity acting on the movable element in the second direction. The control method described in item 11, characterized by the following:

[0145] (Item 18) If the stator has a straight section and a curved section, in the above step, the magnitude of the thrust in the second direction is determined such that the change in the contact force of the movable part in the straight section and the contact force in the curved section is small at the boundary between adjacent straight and curved sections. The control method according to item 10, characterized by the following:

[0146] (Item 19) A stator having a curved section, A movable element that moves along a first direction while in contact with the stator, The system includes a control unit that controls the position and speed of the movable element, The control unit applies a thrust to the movable element in a second direction perpendicular to the first direction when the movable element moves along the curved section. A transport system characterized by the following features.

[0147] (Item 20) A manufacturing method for producing articles using a conveying device described in any one of items 1 to 9, A process of transporting a workpiece mounted on the aforementioned movable element, A process of processing the workpiece using an apparatus for processing articles, A method for manufacturing an article, characterized by having the following: [Explanation of Symbols]

[0148] 1. Conveying System 2 Stator 3 Mover 10 Control Unit 22 Curve Modules 41 d-axis thrust

Claims

1. A stator having a curved section, The system includes a control unit that controls the position and speed of a movable element that moves along a first direction while in contact with the stator, The control unit applies a thrust to the movable element in a second direction perpendicular to the first direction when the movable element moves along the curved section. A conveying device characterized by the following features.

2. The control unit determines the magnitude of the thrust in the second direction based on the magnitude of the external force acting on the movable element in the second direction. The conveying device according to feature 1.

3. The conveying device according to claim 2, characterized in that the external force is a centrifugal force acting on the movable element.

4. The conveying device according to claim 3, characterized in that the control unit derives the magnitude of the centrifugal force based on the drive profile of the movable element.

5. The stator has a coil, The control unit determines the magnitude of the thrust in the second direction based on the magnitude of the attractive force acting between the coil and the permanent magnet of the movable element. The conveying device according to feature 2.

6. The control unit distributes and applies the thrust in the second direction to the front and rear portions of the movable element along the first direction. The conveying device according to feature 1.

7. The control unit determines the distribution ratio between the front and rear portions in the distribution based on the drive profile of the movable element. The conveying device according to feature 6.

8. The stator is, at least a portion of which is extended in a vertical plane, The control unit determines the magnitude of the thrust in the second direction based on the magnitude of the component of gravity acting on the movable element in the second direction. The conveying device according to feature 2.

9. The stator has a straight section and a curved section. The control unit determines the magnitude of the thrust in the second direction such that the change in the contact force of the movable element in the straight section and the contact force in the curved section is minimized at the boundary between the adjacent straight section and the curved section. The conveying device according to feature 1.

10. A control method for a conveying device having a stator having a curved section and a control unit that controls the position and speed of a movable element that moves along a first direction while in contact with the stator, When the movable element moves along the curved section, a step is performed to apply a thrust to the movable element in a second direction perpendicular to the first direction. A control method characterized by the following:

11. In the above step, the magnitude of the thrust in the second direction is determined based on the magnitude of the external force acting on the movable element in the second direction. The control method according to feature 10.

12. The control method according to claim 11, characterized in that the external force is a centrifugal force acting on the movable element.

13. The control method according to claim 12, characterized in that the centrifugal force is derived based on the drive profile of the movable element.

14. In the above step, the magnitude of the thrust in the second direction is determined based on the magnitude of the attractive force acting between the coil as the stator and the permanent magnet as the movable element. The control method according to feature 11.

15. In the above process, the thrust in the second direction is distributed and applied to the front and rear portions of the movable element along the first direction. The control method according to feature 10.

16. The distribution ratio between the front and rear portions in the distribution is determined by the drive profile of the movable element. The control method according to feature 15.

17. If at least a portion of the stator extends in a vertical plane, the magnitude of the thrust in the second direction is determined in the step based on the magnitude of the component of gravity acting on the movable element in the second direction. The control method according to feature 11.

18. If the stator has a straight section and a curved section, in the above step, the magnitude of the thrust in the second direction is determined such that the change in the contact force of the movable part in the straight section and the contact force in the curved section is small at the boundary between adjacent straight and curved sections. The control method according to feature 10.

19. A stator having a curved section, A movable element that moves along a first direction while in contact with the stator, The system includes a control unit that controls the position and speed of the movable element, The control unit applies a thrust to the movable element in a second direction perpendicular to the first direction when the movable element moves along the curved section. A transport system characterized by the following features.

20. A method for manufacturing an article using a conveying device according to any one of claims 1 to 9, A process of transporting a workpiece mounted on the aforementioned movable element, A process of processing the workpiece using an apparatus for processing articles, A method for manufacturing an article, characterized by having the following:

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