Control device, conveyance system, and control method

Abstract

A control device (3) comprises: a storage unit (14) storing a table in which first position information, which represents a position set in a conveyor track (20), and second position information, which indicates the position of a second movable member (22) when a first movable member (21) is at the set position and the spacing between a first jig (24) and a second jig (25) is a preset value, are associated with each other; a first position command generation unit (11) that generates a first position command for moving the first movable member (21); and a second position command generation unit (12) that generates a second position command for moving the second movable member (22) to a position obtained on the basis of the position of the first movable member (21) and the table.

Description

Control device, conveyance system, and control method

[0001] The present disclosure relates to a control device that controls a linear motor conveyance device, a conveyance system, and a control method.

[0002] As a linear motor conveyance device including a stator provided on a conveyance path and a mover moving along the conveyance path, a device that conveys an object held by two movers is known. For example, a linear motor conveyance device that conveys an object placed on jigs attached to two movers respectively moves the two movers while keeping the interval between the two jigs constant. In this case, the control device that controls the linear motor conveyance device performs cooperative control of the two movers so that the interval between the two jigs is kept constant.

[0003] Patent Document 1 discloses a linear motor conveyance device including a guide portion having a stator and a plurality of shuttles moving along the guide portion. In the linear motor conveyance device according to Patent Document 1, a mover is housed in each shuttle. The linear motor conveyance device according to Patent Document 1 moves each shuttle along the guide portion having a straight section and a curved section.

[0004] The linear motor conveyance device according to Patent Document 1 moves a master shuttle, which is a shuttle whose absolute position is controlled, and a slave shuttle, which is a shuttle whose relative position to the master shuttle is controlled. A conveyed object is held by the master shuttle and the slave shuttle. The conveyed object is conveyed as the master shuttle and the slave shuttle move along the guide portion. In the straight section, the distance between the master shuttle and the slave shuttle is adjusted to L1, which is a distance at which the conveyed object can be held. In the curved section, the distance between the master shuttle and the slave shuttle in the curved direction is adjusted to L11, which is shorter than L1. Accordingly, the linear motor conveyance device according to Patent Document 1 controls the master shuttle and the slave shuttle such that the interval between the master shuttle and the slave shuttle in the guide portion is kept constant.

[0005] International Publication No. 2022 / 209837

[0006] The technology described in Patent Document 1 can be applied to a linear motor conveying device that conveys objects using two movable elements to which jigs are attached. When the curved section is a simple arc shape, the technology described in Patent Document 1 makes it possible to maintain a constant distance between the two jigs.

[0007] The transport path of a linear motor transport system may include curved sections with non-constant curvature, such as transition curves. When a curved section with non-constant curvature is included in the transport path, the distance between the two movable parts in the direction of the curve must be adjusted in order to maintain a constant distance between the two fixtures as the two movable parts move along the curved section.

[0008] In the technology described in Patent Document 1, when each movable element moves along a curved section, the distance between the two movable elements in the direction of the curve is kept constant. Therefore, in the technology described in Patent Document 1, for example, in a curved section with a shape that does not have a constant curvature, it becomes impossible to keep the distance between the two jigs constant, making it difficult to stably transport the conveyed object. Thus, the technology described in Patent Document 1 had the problem that it was sometimes not possible to stably transport the conveyed object using a linear motor conveying device.

[0009] This disclosure has been made in view of the above, and aims to provide a control device that enables the stable transport of objects by a linear motor transport device.

[0010] To solve the above-mentioned problems and achieve the objective, the control device according to the present disclosure is a control device for controlling a linear motor transport device that transports an object held by a first jig attached to the first movable element and a second jig attached to the second movable element, comprising a stator provided on a transport path and a first movable element and a second movable element that move along the transport path. The control device according to the present disclosure includes a storage unit that stores a table in which first position information representing a set position on the transport path and second position information indicating the position of the second movable element when the distance between the first jig and the second jig is a preset distance when the first movable element is at the set position are associated with each other; a first position command generation unit that generates a first position command for moving the first movable element; and a second position command generation unit that generates a second position command for moving the second movable element to a position determined based on the position of the first movable element and the table.

[0011] The control device described herein has the effect of enabling the linear motor transport device to stably transport the transported object.

[0012] Figures showing an example of the configuration of a transport system according to Embodiment 1. Figures showing an example of a table stored in the storage unit of the control device according to Embodiment 1. Figures showing an example of a plurality of positions pre-set on the transport path in Embodiment 1. Figures explaining an example of a method for calculating second position information using the table generation device according to Embodiment 1. Flowchart showing an example of the processing procedure by the table generation device according to Embodiment 1. Flowchart showing an example of the processing procedure by the second position command generation unit of the control device according to Embodiment 1. Figures showing an example of the configuration of a control device according to a modified example of Embodiment 1. Figures showing an example of a plurality of positions pre-set on the transport path in Embodiment 2. Figures showing an example of a plurality of positions pre-set on the transport path in a modified example of Embodiment 2. Figures showing an example of a table stored in the storage unit of the control device according to Embodiment 3. Figures showing an example of a plurality of positions pre-set on the transport path in Embodiment 3. Figures showing an example of the configuration of a control circuit according to Embodiments 1 to 3. Figures showing an example of the configuration of a dedicated hardware circuit according to Embodiments 1 to 3.

[0013] The control device, transport system, and control method according to the embodiment will be described in detail below with reference to the drawings.

[0014] Embodiment 1. Figure 1 is a diagram showing an example of the configuration of a transport system 1 according to Embodiment 1. The transport system 1 comprises a linear motor transport device 2 for transporting objects, a control device 3 for controlling the linear motor transport device 2, and a table generation device 4. Hereinafter, the objects transported by the linear motor transport device 2 will be referred to as workpieces.

[0015] The linear motor transport device 2 comprises a first movable element 21, a second movable element 22, and a plurality of rail modules 23. The plurality of rail modules 23 are connected to each other and constitute a transport path 20. Each rail module 23 is a stator that constitutes a linear motor. The first movable element 21 and the second movable element 22 move along the transport path 20.

[0016] The straight section 23a is a straight rail module 23 that constitutes a straight path. The curved section 23b is a curved rail module 23 that constitutes a curved path. The transport path 20 shown in Figure 1 is composed of four straight sections 23a and four curved sections 23b. The number of straight sections 23a and curved sections 23b that constitute the transport path 20 is arbitrary. The transport path 20 shown in Figure 1 is a closed path in the shape of a track. The transport path 20 of the transport system 1 may also be an open path. That is, the transport path 20 of the transport system 1 may be a path with a start point and an end point that are far apart from each other. The transport path 20 may also consist only of curved sections 23b and have no straight sections 23a. The overall shape of the transport path 20 is arbitrary.

[0017] Each of the first movable element 21 and the second movable element 22 has a permanent magnet. Each rail module 23 has a coil and an inverter that adjusts the current flowing through the coil. The coil of each rail module 23 generates a magnetic field when current flows through it. The interaction between this magnetic field and the magnetic fields generated by the permanent magnets of each of the first movable element 21 and the second movable element 22 generates a thrust that moves the first movable element 21 and the second movable element 22. The first movable element 21 and the second movable element 22 move due to this thrust.

[0018] A jig is attached to each of the first movable element 21 and the second movable element 22. Hereinafter, the jig attached to the first movable element 21 will be referred to as the first jig 24. The jig attached to the second movable element 22 will be referred to as the second jig 25. The linear motor transport device 2 transports the workpiece held by the first jig 24 and the second jig 25.

[0019] For example, the workpiece is placed on the first jig 24 and the second jig 25. Alternatively, the workpiece may be held between the first jig 24 and the second jig 25. The linear motor transport device 2 can stably transport objects that are difficult to transport with a single movable element, such as long or heavy objects. Figure 1 schematically shows the first jig 24 and the second jig 25. The configurations of the first jig 24 and the second jig 25 are arbitrary. The workpiece is not shown in Figure 1.

[0020] In the following explanation, "plane" refers to the plane containing the line representing the transport path 20. The transport path 20 shown in Figure 1 is represented by a single line forming a loop.

[0021] The control point of the first jig 24 is located in a plane shifted position from the control point of the first movable element 21. The control point of the first movable element 21 is the reference point for the position of the first movable element 21 when the control device 3 controls the first movable element 21. The control point of the first jig 24 is the reference point for the position of the first jig 24. For example, the control point of the first movable element 21 is set at the position on the first movable element 21 to which the first jig 24 is attached. For example, the control point of the first jig 24 is set at the tip of the first jig 24. The position of the control point on the first movable element 21 is arbitrary. The position of the control point on the first jig 24 is arbitrary. The first jig 24 is fixed to the first movable element 21. The positional relationship between the control point of the first movable element 21 and the control point of the first jig 24 is fixed.

[0022] The control point of the second jig 25 is located in a plane shifted position from the control point of the second movable element 22. The control point of the second movable element 22 is the reference point for the position of the second movable element 22 when the control device 3 controls the second movable element 22. The control point of the second jig 25 is the reference point for the position of the second jig 25. For example, the control point of the second movable element 22 is set at the position on the second movable element 22 to which the second jig 25 is attached. For example, the control point of the second jig 25 is set at the tip of the second jig 25. The position of the control point on the second movable element 22 is arbitrary. The position of the control point on the second jig 25 is arbitrary. The second jig 25 is fixed to the second movable element 22. The positional relationship between the control point of the second movable element 22 and the control point of the second jig 25 is fixed.

[0023] When holding a workpiece, the distance between the control point of the first jig 24 and the control point of the second jig 25 is adjusted to a predetermined distance D. Here, the distance between the control point of the first jig 24 and the control point of the second jig 25 is called the jig distance. The linear motor transport device 2 moves the first movable element 21 and the second movable element 22 while maintaining the jig distance at a constant distance D. The control device 3 controls the first movable element 21 and the second movable element 22 to coordinate with each other so that the jig distance is a constant distance D.

[0024] The first movable element 21 and the second movable element 22 are capable of moving in the forward direction and in the reverse direction along the transport path 20. For example, in the transport path 20 shown in Figure 1, the forward direction is the opposite direction to clockwise in Figure 1, and the reverse direction is the same as clockwise in Figure 1.

[0025] Figure 1 shows one pair of first movable elements 21 and second movable elements 22, but the pair of first movable elements 21 and second movable elements 22 that moves along the transport path 20 is not limited to one. The linear motor transport device 2 may move multiple pairs of first movable elements 21 and second movable elements 22.

[0026] A linear scale is attached to the transport path 20 to detect the positions of the first movable element 21 and the second movable element 22, or the speeds of the first movable element 21 and the second movable element 22. The linear scale is not shown in Figure 1.

[0027] The control device 3 comprises a first position command generation unit 11, a second position command generation unit 12, a drive control unit 13, and a storage unit 14. The first position command generation unit 11 generates a first position command, which is a position command for moving the first movable element 21. The first position command includes information indicating the target position on the transport path 20 where the first movable element 21 will be moved. The first position command generation unit 11 outputs the first position command to the second position command generation unit 12 and the drive control unit 13, respectively. The first position command generation unit 11 outputs the first position command at a preset time period.

[0028] The command speed is expressed as the time derivative of the waveform representing the time change of the signal that is the first position command, or as the difference between two signals that are the first position command. Examples of command speed patterns include trapezoidal acceleration / deceleration and triangular acceleration / deceleration. Trapezoidal acceleration / deceleration is acceleration / deceleration such that the graph representing the relationship between time and speed is a trapezoid. Triangular acceleration / deceleration is acceleration / deceleration such that the graph representing the relationship between time and speed is a triangle.

[0029] The second position command generation unit 12 generates a second position command, which is a position command for moving the second movable element 22. The second position command includes information indicating the target position on the transport path 20 where the second movable element 22 will be moved. The second position command generation unit 12 outputs the second position command at a preset time period. The second position command generation unit 12 outputs the second position command to the drive control unit 13.

[0030] The storage unit 14 stores a table. The table stored in the storage unit 14 has a first position information that represents a position set in the transport path 20, and a second position information that indicates the position of the second movable element 22 when the distance between the first jig 24 and the second jig 25 is a predetermined distance D, assuming that the first movable element 21 is at the set position.

[0031] The second position command generation unit 12 generates a second position command to move the second movable element 22 to a position determined based on the table stored in the storage unit 14 and the first position command. Details of how the second position command generation unit 12 generates the second position command, and details of the table stored in the storage unit 14, will be described later.

[0032] The drive control unit 13 receives a first position command and a second position command from the control device 3 and drives the linear motor transport device 2. The drive control unit 13 is, for example, a power amplifier. The drive control unit 13 controls the first movable element 21 and the second movable element 22 by controlling the current flowing to the linear motor transport device 2. In response to the first position command, the drive control unit 13 supplies current to the rail module 23 that generates thrust to move the first movable element 21. In response to the second position command, the drive control unit 13 supplies current to the rail module 23 that generates thrust to move the second movable element 22.

[0033] In Figure 1, the first position command generation unit 11, the second position command generation unit 12, the drive control unit 13, and the storage unit 14 are provided in a single device, the control device 3. The first position command generation unit 11, the second position command generation unit 12, the drive control unit 13, and the storage unit 14 may be distributed across two or more devices. For example, the drive control unit 13 may be provided in a device separate from the device that provides the first position command generation unit 11, the second position command generation unit 12, and the storage unit 14. The drive control unit 13 may be integrated with the transport path 20.

[0034] The drive control unit 13 has a control loop that controls the current based on the difference between the position of the first movable element 21 detected by the linear scale and the position indicated in the first position command, and a control loop that controls the current based on the difference between the position of the second movable element 22 detected by the linear scale and the position indicated in the second position command. The drive control unit 13 performs feedback control of the first movable element 21 and the second movable element 22 using these control loops.

[0035] The table generation device 4 is implemented by a computer system. The table generation device 4 generates a table. The table generation device 4 receives information indicating a set distance D, information indicating the specifications of the first jig 24 and the second jig 25, and information indicating the configuration of the transport path 20. The table generation device 4 generates a table based on this input information. The table generated by the table generation device 4 is stored in the storage unit 14.

[0036] Next, the tables stored in the storage unit 14 will be described. Figure 2 is a diagram showing an example of a table stored in the storage unit 14 of the control device 3 according to Embodiment 1.

[0037] The position numbers shown in the first column of the table are numbers assigned to each of the multiple positions pre-set on the transport path 20. Each of the multiple positions set on the transport path 20 can be identified by its position number. The position number is also the index assigned to each row of the table. In the following explanation, "i" represents the position number. "i" is any integer from 1 to N. N represents the number of positions set on the transport path 20. N is also the number of rows in the table. The multiple positions set on the transport path 20 are represented as P1, P2, P3, ..., PN. P1 represents the position i=1. Similarly, P2 to PN each represent the positions i=2, ..., i=N. P1 is the reference position on the transport path 20. The multiple positions are arranged in the order P1, P2, P3, ..., PN in the forward direction of the transport path 20. L represents the length of one circumference of the transport path 20.

[0038] Figure 3 shows an example of multiple positions pre-set on the transport path 20 in Embodiment 1. In Figure 3, the transport path 20 is represented by a single loop line. The black circles shown in Figure 3 represent points that indicate a set position. In Figure 3, the points representing each pre-set position are arranged at equal intervals. Here, it is assumed that N positions are set on the transport path 20 at intervals of 100 μm (micrometers). Note that the interval between each position is not limited to 100 μm and can be arbitrary.

[0039] In Figure 2, the first position information shown in the second column of the table represents the location of the set position. The first position information can also be said to be information for identifying the set position from within the transport path 20. The second column of the table stores the first position information representing each of the multiple positions set in the transport path 20. Here, the first position information represents the distance from the reference position P1. In Figure 2, the first position information is represented only by numerical values, and the unit of distance, "μm", is omitted. "X(i)" represents the first position information. In the example shown in Figure 2, X(1) = 0, X(2) = 100, ..., X(N) = L.

[0040] The second position information shown in the third column of the table represents the position of the second movable element 22 when the gap between the first jig 24 and the second jig 25 becomes distance D when the first movable element 21 is located at the position indicated by the first position information. The second position information is information representing the distance from P1, which is the reference position. "Y(i)" is defined to represent the second position information. In FIG. 2, the second position information is shown as Y(1), Y(2), ..., Y(N), but specific numerical values are stored in the table as the second position information.

[0041] In this way, pairs of the numerical value as the first position information and the numerical value as the second position information are written in the N rows of the table. The first position information and the second position information for each of the plurality of positions preset on the transport path 20 are associated with each other in the table.

[0042] Next, an example of a method for calculating the second position information by the table generating device 4 will be described. FIG. 4 is a diagram for explaining an example of the method for calculating the second position information by the table generating device 4 according to the first embodiment.

[0043] In FIG. 4, a portion of the transport path 20 where the linear portion 23a and the curved portion 23b are connected to each other is represented by a single line. The control point 31 is a control point of the first movable element 21. The control point 32 is a control point of the second movable element 22. In FIG. 4, the position of the first movable element 21 is represented by the control point 31, and illustration of the first movable element 21 is omitted. In FIG. 4, the position of the second movable element 22 is represented by the control point 32, and illustration of the second movable element 22 is omitted. The control point 33 is a control point of the first jig 24. The control point 34 is a control point of the second jig 25.

[0044] In FIG. 4, with P1 as the first position, the state of the linear motor transport device 2 when the control point 31 reaches Pk, which is the k-th position from P1, is schematically illustrated. Pk is a position on the curved portion 23b. X(k), which is the first position information for Pk, represents the movement distance from P1 to Pk. The tangent line TL is a tangent line to the line representing the transport path 20. FIG. 4 shows the tangent line TL at Pk.

[0045] w1 and w2 are parameters representing the length of the first jig 24, and represent the offset of control point 33 from control point 31. w1 represents the length of the first jig 24 in the normal direction of the transport path 20. w2 represents the length of the first jig 24 in the tangential direction of the transport path 20. The normal direction is the direction perpendicular to the tangential line TL. The tangential direction is the direction of the tangential line TL. w1 and w2 are included in the specifications of the first jig 24. Similarly to the first jig 24, the specifications of the second jig 25 also include a parameter representing the offset of control point 34 from control point 32. The offset described here is an offset in a plane. Both the normal direction and the tangential direction are directions included in the plane.

[0046] θ represents the tangent angle, which is the angle between the reference line and the tangent line TL. Here, the reference line is the straight line representing the straight section 23a of the transport path 20 that includes P1. Note that the method of determining the reference line is arbitrary. The interval d is the distance between the first jig 24 and the second jig 25. Specifically, the interval d is the jig interval, that is, the distance between control point 33 and control point 34.

[0047] The table generation device 4 receives information indicating a set distance D, information indicating the specifications of the first jig 24, information indicating the specifications of the second jig 25, and information indicating the configuration of the transport path 20. The distance D is set appropriately according to the size of the workpiece to be transported. The information indicating the specifications of the first jig 24 includes a value indicating the offset of control point 33 from control point 31. That is, the information indicating the specifications of the first jig 24 includes a value indicating the length of the first jig 24 in the normal direction and a value indicating the length of the first jig 24 in the tangential direction. The information indicating the specifications of the second jig 25 includes a value indicating the offset of control point 34 from control point 32. That is, the information indicating the specifications of the second jig 25 includes a value indicating the length of the second jig 25 in the normal direction and a value indicating the length of the second jig 25 in the tangential direction.

[0048] First position information for each of P1 to PN set for the transport path 20 is input to the table generation device 4. The table generation device 4 stores the input first position information in a table. The table generation device 4 obtains coordinates on a plane for each of P1 to PN based on information indicating the configuration of the transport path 20 and the first position information for each of P1 to PN. The origin (0, 0) of the coordinates is aligned with P1. The information indicating the configuration of the transport path 20 includes information on the shape of the transport path 20, such as the length of linear portions of the transport path 20, and the length and curvature of curved portions of the transport path 20. From the information indicating the configuration of the transport path 20, θ, which is the tangent angle, can be obtained for each of P1 to PN.

[0049] Here, a method for calculating Y(k), which is second position information corresponding to X(k) which is first position information for Pk, will be described. The table generation device 4 obtains the coordinates of the control point 32 when an interval d matches a distance D based on the coordinates of Pk, a value indicating an offset of the control point 33 from the control point 31, and a value indicating an offset of the control point 34 from the control point 32. Next, the table generation device 4 obtains the distance from P1 to the control point 32 when the interval d matches the distance D based on the coordinates of the control point 32 and the information indicating the configuration of the transport path 20. Thereby, the table generation device 4 calculates Y(k), which is the second position information.

[0050] The table generation device 4 calculates second position information corresponding to first position information for each position other than Pk, in the same manner as for Pk. The table generation device 4 generates a table in which the first position information and the second position information for each of P1 to PN are stored. Note that the method for calculating the second position information by the table generation device 4 is not limited to the above method. The table generation device 4 may calculate the second position information by a method other than the above.

[0051] When the control device 3 controls the linear motor transport device 2, the table in the storage unit 14 stores second position information that has been pre-calculated by the table generation device 4 as described above. The table stores second position information that has been pre-calculated based on a value indicating a pre-set distance D, a value indicating the offset of the control point of the first jig 24 from the control point of the first movable element 21, a value indicating the offset of the control point of the second jig 25 from the control point of the second movable element 22, coordinates indicating a position set in the transport path 20, and the angle of the tangent to the line representing the transport path 20 at the position indicated by the coordinates.

[0052] Figure 5 is a flowchart showing an example of the processing procedure by the table generation device 4 according to Embodiment 1. Here, we will explain the processing procedure when calculating the second position information.

[0053] In step S1, the table generation device 4 sets "i" to 1. In step S2, the table generation device 4 retrieves X(i) stored in the second column of the table. In the first step S2 after the process shown in Figure 5 has started, the table generation device 4 retrieves X(1).

[0054] In step S3, the table generation device 4 calculates the coordinates of the control point 31, which is the control point of the first movable element 21, from X(i) obtained in step S2. The table generation device 4 calculates the coordinates of the control point 31 based on the information showing the configuration of the transport path 20 and X(i).

[0055] In step S4, the table generation device 4 calculates the coordinates of the control point 33, which is the control point of the first jig 24, from the coordinates of the control point of the first movable element 21, which are the coordinates calculated in step S3. The table generation device 4 calculates the coordinates of the control point 33 based on the value indicating the offset of the control point 33 from the control point 31 and θ in the coordinates calculated in step S3.

[0056] In step S5, the table generation device 4 calculates Y(i). The table generation device 4 sets the provisional coordinates of control point 32, which is the control point of the second movable element 22. Based on the set provisional coordinates, the value indicating the offset of control point 34 from control point 32, and θ in the set provisional coordinates, the table generation device 4 calculates the provisional coordinates of control point 34. Based on the coordinates of control point 33 and the provisional coordinates of control point 34 calculated in step S4, the table generation device 4 determines the interval d between control point 33 and control point 34. If the interval d does not match the distance D, the table generation device 4 changes the provisional coordinates of control point 32 and repeats the same calculation as above. The table generation device 4 calculates the coordinates of control point 32 when the interval d matches the distance D as Y(i). In this way, the table generation device 4 calculates Y(i) by numerical calculation. Alternatively, if the table generation device 4 can express the entire geometric shape of the transport path 20 using mathematical formulas, it may calculate Y(i) using an analytical method.

[0057] In step S6, the table generation device 4 determines whether the currently set value of "i" is equal to N. If the value of "i" is not equal to N (step S6, No), in step S7, the table generation device 4 adds 1 to the currently set value of "i". Then, the table generation device 4 repeats the procedure from step S2 to step S6.

[0058] On the other hand, if the value of "i" is equal to N (step S6, Yes), the table generation device 4 terminates the processing according to the procedure shown in Figure 5. As a result, the table generation device 4 calculates the second position information for each of P1 to PN.

[0059] Next, the generation of the second position command by the second position command generation unit 12 will be described. Figure 6 is a flowchart showing an example of the processing procedure by the second position command generation unit 12 of the control device 3 according to Embodiment 1.

[0060] In step S11, the second position command generation unit 12 acquires the first position command from the first position command generation unit 11. That is, the second position command generation unit 12 acquires the first position command generated by the first position command generation unit 11.

[0061] The first position command indicates the target position to which the first movable element 21 will be moved. Here, x is the value representing the position indicated by the first position command. x is a numerical value representing the distance from the reference P1. The second position command generation unit 12 obtains the value of x by acquiring the first position command in step S11.

[0062] In step S12, the second position command generation unit 12 searches the table stored in the storage unit 14 for a value of "i" that satisfies X(i) ≤ x < X(i+1). By comparing each value stored in the second column of the table with the value of x, it finds a value of "i" that satisfies X(i) ≤ x < X(i+1).

[0063] In step S13, the second position command generation unit 12 calculates y by interpolating the second position information. Here, y is the value representing the target position to which the second movable element 22 will be moved. The second position command generation unit 12 reads the X(i) and Y(i) values ​​stored in the row of the table corresponding to the value of "i" obtained in step S12. The second position command generation unit 12 also reads the X(i+1) and Y(i+1) values ​​stored in the row following the row of the table corresponding to the value of "i" obtained in step S12, i.e., the row corresponding to the value of "i+1". The second position command generation unit 12 calculates the value of y, for example, by linear interpolation.

[0064] When the second position command generation unit 12 performs linear interpolation, it calculates the value of y using, for example, the following equation (1): y = [{x - X(i)} × {Y(i+1) - Y(i)} / {X(i+1) - X(i)}] + Y(i) ... (1)

[0065] The second position command generation unit 12 can calculate a value of y that corresponds to the value of x and satisfies Y(i) ≤ y < Y(i+1) through interpolation. Note that the interpolation process performed by the second position command generation unit 12 is not limited to linear interpolation. The second position command generation unit 12 may calculate the value of y by interpolation other than linear interpolation. For example, the second position command generation unit 12 may calculate the value of y by spline interpolation, nearest neighbor interpolation, or Newton interpolation.

[0066] In this way, the second position command generation unit 12 generates a second position command that includes a value of y, which is information indicating the target position to move the second movable element 22. In step S14, the second position command generation unit 12 outputs the generated second position command. With this, the second position command generation unit 12 completes the processing according to the procedure shown in Figure 6.

[0067] The second position command generation unit 12 executes the process according to steps S11 to S14 at a preset time cycle. The linear motor transport device 2 moves the first movable element 21 according to the first position command and moves the second movable element 22 according to the second position command, thereby maintaining a constant distance between the first jig 24 and the second jig 25. As a result, the linear motor transport device 2 can transport the workpiece stably.

[0068] The linear motor transport device 2 can maintain a constant distance between the first jig 24 and the second jig 25 regardless of the shape of the transport path 20. For example, even when the transport path 20 includes a section with an irregular curvature, the distance between the first jig 24 and the second jig 25 can be maintained constant. Furthermore, the linear motor transport device 2 can maintain a constant distance between the first jig 24 and the second jig 25 when one of the first movable element 21 and the second movable element 22 is in a straight section 23a and the other is in a curved section 23b.

[0069] In the above, the second position command generation unit 12 generates the second position command based on the first position command and the table. In this case, the second position command generation unit 12 obtains the first position command, which is information indicating the position of the first movable element 21, and determines the position of the second movable element 22 based on the position indicated in the first position command and the table.

[0070] The information indicating the position of the first movable element 21, acquired by the second position command generation unit 12, is not limited to the first position command. The second position command generation unit 12 may also acquire information other than the first position command as information indicating the position of the first movable element 21.

[0071] For example, the information indicating the position of the first movable element 21 may be the result of detecting the position of the first movable element 21 using a linear scale. In this case, the second position command generation unit 12 obtains the result of detecting the position of the first movable element 21 and determines the position of the second movable element 22 based on the detected position of the first movable element 21 and a table. Thus, the second position command generation unit 12 may generate a second position command based on the result of detecting the position of the first movable element 21 and a table.

[0072] The second position command generation unit 12 may use information obtained by filtering the first position command as information indicating the position of the first movable element 21. A filter having low-pass characteristics is used for filtering. Alternatively, the second position command generation unit 12 may use information obtained by filtering the result of detecting the position of the first movable element 21 using a linear scale as information indicating the position of the first movable element 21. In this case as well, a filter having low-pass characteristics is used for filtering. Thus, the second position command generation unit 12 may generate a second position command based on the result of processing the first position command with a filter having low-pass characteristics, or the result of processing the result of detecting the position of the first movable element 21 with a filter having low-pass characteristics, and a table.

[0073] According to Embodiment 1, the control device 3 includes a storage unit 14 that stores a table in which first position information representing a set position in the transport path 20 and second position information indicating the position of the second movable element 22 when the distance between the first jig 24 and the second jig 25 is a preset distance when the first movable element 21 is at the set position are associated with each other; a first position command generation unit 11 that generates a first position command for moving the first movable element 21; and a second position command generation unit 12 that generates a second position command for moving the second movable element 22 to a position determined based on the position of the first movable element 21 and the table.

[0074] The control device 3 can control the first movable element 21 and the second movable element 22 so that the distance between the first jig 24 and the second jig 25 remains constant when the transport path 20 includes a curved section with an irregular curvature. The control device 3 can also control the first movable element 21 and the second movable element 22 so that the distance between the first jig 24 and the second jig 25 remains constant when one of the first movable element 21 and the other is in a straight section and the other is in a curved section. As a result, the linear motor transport device 2 can stably transport the transported object. Furthermore, by referring to a table in which the first position information and the second position information are associated with each other when the distance between the first jig 24 and the second jig 25 is a preset distance, the control device 3 can determine the position of the second movable element 22 with minimal computational load. This allows the control device 3 to reduce the computational load performed simultaneously with the control of the linear motor transport device 2.

[0075] Furthermore, the second position command generation unit 12 may determine the position to move the second movable element 22 by interpolating the second position information read from the table, and generate a second position command to move the second movable element 22 to the determined position. This allows the control device 3 to control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant.

[0076] Furthermore, the table stores second position information that has been pre-calculated based on a value indicating a pre-set distance, a value indicating the offset of the control point of the first jig 24 from the control point of the first movable element 21, a value indicating the offset of the control point of the second jig 25 from the control point of the second movable element 22, coordinates indicating a position set in the transport path 20, and the angle of the tangent to the line representing the transport path 20 at the position indicated by the coordinates. As a result, the control device 3 can generate a second position command that keeps the distance between the first jig 24 and the second jig 25 constant, based on the position of the first movable element 21 and the table.

[0077] According to Embodiment 1, the transport system 1 includes a table generating device 4 that generates tables, and the storage unit 14 stores the tables generated by the table generating device 4. The control device 3 can control the first movable element 21 and the second movable element 22 so that the distance between the first jig 24 and the second jig 25 is a preset distance. As a result, the transport system 1 can stably transport objects using the linear motor transport device 2.

[0078] Next, a modified version of the control device 3 will be described. In the above description, the table is generated by a table generation device 4 located outside the control device 3. The transport system 1 may also generate the table inside the control device 3.

[0079] Figure 7 shows an example of the configuration of a control device 3A according to a modified embodiment of the first embodiment. The control device 3A is provided in the transport system 1 instead of the control device 3 and table generation device 4 shown in Figure 1. The control device 3A has the same configuration as the control device 3 shown in Figure 1. The control device 3A also includes a table generation unit 15 that generates tables.

[0080] The table generation unit 15 receives information indicating a set distance D, information indicating the specifications of the first jig 24 and the second jig 25, and information indicating the configuration of the transport path 20. The table generation unit 15 calculates the second position information according to the procedure shown in Figure 5, similar to the table generation device 4. The table generated by the table generation unit 15 is stored in the storage unit 14. Even if the transport system 1 is equipped with a control device 3A, the transport system 1 can control the first movable element 21 and the second movable element 22 so that the distance between the first jig 24 and the second jig 25 is a preset distance.

[0081] Embodiment 2. In Embodiment 1, a plurality of predetermined positions were arranged at equal intervals along the transport path 20. In Embodiment 2, an example is described in which the intervals between adjacent positions within the plurality of positions are different. The transport system 1 according to Embodiment 2 has the same configuration as the transport system 1 shown in Figure 1. Embodiment 2 mainly describes aspects that differ from Embodiment 1.

[0082] Figure 8 shows examples of multiple positions pre-set on the transport path 20 in Embodiment 2. In Figure 8, the transport path 20 is represented by a single loop line. The black circles shown in Figure 8 represent the set positions.

[0083] In the example shown in Figure 8, the points representing the set positions are arranged at equal intervals in the straight portion of the transport path 20. The points representing the set positions are also arranged at equal intervals in the curved portion of the transport path 20. The spacing between points in the straight portion is greater than the spacing between points in the curved portion. In this way, the points in the curved portion are arranged more densely than the points in the straight portion. That is, the multiple positions set in the transport path 20 are arranged to be denser in the curved portion than in the straight portion.

[0084] Because the multiple positions set in the transport path 20 are more densely packed in the curved section, the position of the second movable element 22 is adjusted at more positions when the first movable element 21 and the second movable element 22 pass through the curved section. Therefore, the control device 3 can control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant in the curved section. For example, if the curvature in the curved section is not constant, the control device 3 can adjust the position of the second movable element 22 with high precision in accordance with the change in curvature.

[0085] When the first movable element 21 and the second movable element 22 pass through a linear section, the distance between the first movable element 21 and the second movable element 22 is kept constant, thereby keeping the distance between the first jig 24 and the second jig 25 constant. In the linear section, even if the distance between the set positions is large, the interpolation process in the procedure shown in Figure 6 makes it possible to keep the distance between the first jig 24 and the second jig 25 constant. For this reason, the control device 3 can control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant, even when the number of set positions is small in the linear section.

[0086] Furthermore, in this case, the number of rows in the table can be reduced by decreasing the number of pre-set positions for the linear portion. Reducing the number of rows in the table reduces the data size of the table. As a result, the control device 3 can store the table in the storage unit 14 with a small data capacity.

[0087] According to Embodiment 2, the transport path 20 includes a straight section and a curved section, and the table stores first position information representing a plurality of positions set in the transport path 20, with the plurality of positions being set to be more densely located in the curved section than in the straight section. The control device 3 can control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant. As a result, the linear motor transport device 2 can transport objects stably. In addition, by reducing the data size of the table, the storage capacity of the control device 3 can be reduced.

[0088] Next, a modified example of Embodiment 2 will be described. The modified example of Embodiment 2 is an example in which the spacing between adjacent positions among multiple positions is varied, and is a different example from the example shown in Figure 8.

[0089] Figure 9 shows examples of multiple positions pre-set on the transport path 20 in a modified example of Embodiment 2. In Figure 9, the transport path 20 is represented by a single loop line. The black circles shown in Figure 9 represent the set positions.

[0090] In the example shown in Figure 9, multiple positions are set such that the number of positions in the transport path 20 is denser in the portion where at least one of the positions indicated by the first position information and the second position information is included in a curved portion than in the portion where both positions indicated by the first position information and the second position information are included in a straight portion.

[0091] Figure 9 shows an example where the position indicated by the first position information is contained within a linear portion, and the position indicated by the second position information is contained within a curved portion. In Figure 9, the position of control point 31 represents the position indicated by the first position information, and the position of control point 32 represents the position indicated by the second position information. Figure 9 also shows the first jig 24 and the second jig 25. In the example shown in Figure 9, the first movable element 21 and the second movable element 22 move in the forward direction, which is counterclockwise in Figure 9.

[0092] The portion of the transport path 20 in which both the position indicated by the first position information and the position indicated by the second position information are included in a straight section is referred to as the first section. The portion of the transport path 20 in which at least one of the positions indicated by the first position information and the position indicated by the second position information is included in a curved section is referred to as the second section.

[0093] Here, up, down, right, and left refer to the directions in Figure 9. The upper straight portion of the transport path 20 is designated as section 20a, and the lower straight portion as section 20b. The left curved portion of the transport path 20 is designated as section 20c, and the right straight portion as section 20d.

[0094] When control point 32 reaches the right end of section 20a, both control point 31 and control point 32 enter section 20a. The starting point of the first section of section 20a is a position shifted to the left from the right end of section 20a by a predetermined length. The predetermined length is the length between control point 31 and control point 32 when control points 31 and 32 are aligned in a straight line and the distance between control point 33 and control point 34 is distance D. After control point 31 reaches the left end of section 20a, control point 31 enters section 20c. The ending point of the first section of section 20a is the left end of section 20a.

[0095] When control point 32 reaches the left end of section 20b, both control point 31 and control point 32 enter section 20b. The starting point of the first section of section 20b is a position shifted to the right from the left end of section 20b by the predetermined length mentioned above. After control point 31 reaches the right end of section 20b, control point 31 enters section 20d. The ending point of the first section of section 20b is the right end of section 20b. The second section is the part of the transport path 20 other than the first section. Multiple positions set in the transport path 20 are set to be more densely packed in the second section than in the first section.

[0096] Because the multiple positions set in the transport path 20 are more densely packed in the second section, the position of the second movable element 22 is adjusted at more positions when the first movable element 21 and the second movable element 22 pass through the second section. Therefore, the control device 3 can control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant in the second section. The control device 3 can control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant near the boundary between the straight and curved sections of the transport path 20.

[0097] When the first movable element 21 and the second movable element 22 pass through the first section, the distance between the first movable element 21 and the second movable element 22 is kept constant, thereby keeping the distance between the first jig 24 and the second jig 25 constant. In the first section, even if the distance between the set positions is large, the interpolation process in the procedure shown in Figure 6 makes it possible to keep the distance between the first jig 24 and the second jig 25 constant. For this reason, the control device 3 can control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant, even when the number of set positions in the first section is small.

[0098] Furthermore, in this case, the number of rows in the table can be reduced by decreasing the number of pre-set positions for the first interval. Reducing the number of rows in the table reduces the data size of the table. As a result, the control device 3 can store the table in a storage unit 14 with a small data capacity.

[0099] According to a modification of Embodiment 2, the multiple positions are set to be denser in a second section of the transport path 20, where at least one of the positions indicated by the first position information and the positions indicated by the second position information is included in a curved section, than in a first section of the transport path 20, where both the positions indicated by the first position information and the positions indicated by the second position information are included in a straight section. The control device 3 can control the first movable element 21 and the second movable element 22 with high precision so that the distance between the first jig 24 and the second jig 25 remains constant. As a result, the linear motor transport device 2 can transport the transported object stably. In addition, by reducing the data size of the table, the storage capacity of the control device 3 can be reduced.

[0100] In the above, the transport system 1 according to Embodiment 2 has the same configuration as the transport system 1 shown in Figure 1. The transport system 1 according to Embodiment 2 may also be equipped with the control device 3A shown in Figure 7 instead of the control device 3 and table generation device 4 shown in Figure 1.

[0101] Embodiment 3. In Embodiments 1 and 2, the distance between the first jig 24 and the second jig 25 was kept constant. Embodiment 3 describes an example in which the distance between the first jig 24 and the second jig 25 is varied for each region of the transport path 20. The transport system 1 according to Embodiment 3 has the same configuration as the transport system 1 shown in Figure 1. Embodiment 3 mainly describes the differences from Embodiments 1 or 2.

[0102] In Embodiment 3, for a region of the transport path 20, the first position information and the second position information are set such that the distance between the first jig 24 and the second jig 25 is a first distance, and for a region of the transport path 20 other than that region, the first position information and the second position information are set such that the distance between the first jig 24 and the second jig 25 is a second distance which is different from the first distance.

[0103] Figure 10 shows an example of a table stored in the storage unit 14 of the control device 3 according to Embodiment 3. Figure 11 shows an example of a plurality of positions pre-set on the transport path 20 in Embodiment 3.

[0104] In Embodiment 3, M represents the length of half the circumference of the transport path 20. Multiple positions set on the transport path 20 are represented as P1, P2, P3, ..., PM, P(M+1), P(M+2), ..., PN. In the example shown in Figures 10 and 11, the transport path 20 is divided into two regions. The region encompassing P1 to PM is the first region, and the region encompassing P(M+1) to PN is the second region.

[0105] In the table shown in Figure 10, the second position information shown in the third column, i = 1 to M, represents the position of the second movable element 22 when the distance between the first jig 24 and the second jig 25 is a first distance D1, assuming the first movable element 21 is at the position indicated by the first position information. In the table shown in Figure 10, the second position information shown in the third column, i = (M + 1) to N, represents the position of the second movable element 22 when the distance between the first jig 24 and the second jig 25 is a second distance D2, assuming the first movable element 21 is at the position indicated by the first position information. Thus, the first and second position information are set so that in the first region the distance between the first jig 24 and the second jig 25 is a first distance D1. In the second region the first and second position information are set so that the distance between the first jig 24 and the second jig 25 is a second distance D2.

[0106] The table generation device 4 receives information indicating a set first distance D1, information indicating a set second distance D2, information indicating the specifications of the first jig 24, information indicating the specifications of the second jig 25, and information indicating the configuration of the transport path 20. The first distance D1 is set appropriately according to the size of the workpiece to be transported in the first area. The second distance D2 is set appropriately according to the size of the workpiece to be transported in the second area.

[0107] For i = 1 to M, the table generation device 4 calculates second position information when the distance d between control point 33 and control point 34 is the first distance D1. For i = (M+1) to N, the table generation device 4 calculates second position information when the distance d between control point 33 and control point 34 is the second distance D2.

[0108] The second position command generation unit 12 of the control device 3 generates a second position command for moving the second movable element 22 to a position determined based on the position of the first movable element 21 and the table shown in Figure 10. The control device 3 can control the first movable element 21 and the second movable element 22 such that the interval d is a first distance D1 for the first region and a second distance D2 for the second region.

[0109] In the above, the transport path 20 is assumed to be divided into two regions. In Embodiment 3, the transport path 20 may be divided into three or more regions. In each of the three or more regions, the first position information and the second position information may be set such that the distance between them, d, is different from each other.

[0110] According to Embodiment 3, in a certain region of the transport path 20, the first position information and the second position information are set so that the distance between the first jig 24 and the second jig 25 is a first distance, and in a region of the transport path 20 other than that region, the first position information and the second position information are set so that the distance between the first jig 24 and the second jig 25 is a second distance different from the first distance. As a result, the linear motor transport device 2 can transport workpieces of different sizes in each region of the transport path 20 and transport the objects stably in any region.

[0111] In the above, the transport system 1 according to Embodiment 3 has the same configuration as the transport system 1 shown in Figure 1. The transport system 1 according to Embodiment 3 may also be equipped with the control device 3A shown in Figure 7 instead of the control device 3 and table generation device 4 shown in Figure 1.

[0112] Next, the hardware configuration for realizing the processing units of the control devices 3 and 3A according to Embodiments 1 to 3 will be described. The processing unit of control device 3 consists of a first position command generation unit 11, a second position command generation unit 12, and a storage unit 14, as shown in Figure 1. The processing unit of control device 3A consists of a first position command generation unit 11, a second position command generation unit 12, a storage unit 14, and a table generation unit 15, as shown in Figure 7. The processing units of control devices 3 and 3A are realized by processing circuits. The processing circuits may be circuits in which a processor executes software, or they may be dedicated circuits.

[0113] When the processing circuit is implemented by software, the processing circuit is, for example, the control circuit 50 shown in Figure 12. Figure 12 is a diagram showing an example configuration of the control circuit 50 according to Embodiments 1 to 3. The control circuit 50 includes an input unit 51, a processor 52, a memory 53, and an output unit 54. The input unit 51 is an interface circuit that receives data input from outside the control circuit 50 and provides it to the processor 52. The output unit 54 is an interface circuit that sends data from the processor 52 or the memory 53 to the outside of the control circuit 50.

[0114] The processing units of the control devices 3 and 3A are implemented by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory 53. The control circuit 50 implements the various functions of the processing units of the control devices 3 and 3A by having the processor 52 read and execute the program stored in memory 53. In other words, the control circuit 50 is equipped with memory 53 for storing the program that will ultimately be executed by the processing units of the control devices 3 and 3A. This program can also be said to cause the computer system to execute the procedures and methods of processing that the processing units of the control devices 3 and 3A will perform. Memory 53 is also used as temporary memory when the processor 52 performs various processes.

[0115] The first position command generation unit 11, the second position command generation unit 12, and the table generation unit 15 are implemented using a processor 52 and memory 53. The storage unit 14 is implemented using memory 53.

[0116] The processor 52 is a CPU (Central Processing Unit). The processor 52 may also be a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor). The memory 53 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM® (Electrically Erasable Programmable Read Only Memory), magnetic disk, flexible disk, optical disk, compact disk, minidisc, or DVD (Digital Versatile Disc).

[0117] Figure 12 shows an example of hardware when the functions of the processing units of the control devices 3 and 3A are realized using a general-purpose processor 52 and memory 53. The functions of the processing units of the control devices 3 and 3A may also be realized by dedicated hardware circuits. Figure 13 shows an example of the configuration of a dedicated hardware circuit 55 according to embodiments 1 to 3.

[0118] The dedicated hardware circuit 55 includes an input section 51, an output section 54, and a processing circuit 56. The processing section of the control devices 3 and 3A is realized by the processing circuit 56. The processing circuit 56 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a circuit combining these. Each function of the processing section of the control devices 3 and 3A may be realized by the processing circuit 56 separately, or all functions may be realized together by the processing circuit 56. In addition, the processing section of the control devices 3 and 3A may be realized by combining the control circuit 50 and the hardware circuit 55.

[0119] The table generation device 4 shown in Figure 1 is implemented with a hardware configuration similar to that shown in Figure 12. Alternatively, the table generation device 4 is implemented with a hardware configuration similar to that shown in Figure 13. The table generation device 4 may be equipped with an input device for inputting information and a monitor for displaying information. The input device includes, for example, a keyboard, mouse, keypad, or touch panel. The monitor is, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro-Luminescence) display.

[0120] The configurations shown in each of the embodiments described above are examples of the content of this disclosure. The configurations of each embodiment can be combined with other known technologies. The configurations of each embodiment may be combined with each other as appropriate. It is possible to omit or modify parts of the configurations of each embodiment without departing from the gist of this disclosure.

[0121] 1. Transport system, 2. Linear motor transport device, 3, 3A. Control device, 4. Table generation device, 11. First position command generation unit, 12. Second position command generation unit, 13. Drive control unit, 14. Memory unit, 15. Table generation unit, 20. Transport path, 20a, 20b, 20c, 20d. Sections, 21. First movable element, 22. Second movable element, 23. Rail module, 23a. Straight section, 23b. Curved section, 24. First jig, 25. Second jig, 31, 32, 33, 34. Control points, 50. Control circuit, 51. Input unit, 52. Processor, 53. Memory, 54. Output unit, 55. Hardware circuit, 56. Processing circuit.

Claims

1. A control device for controlling a linear motor transport device that transports an object held by a first jig attached to the first movable element and a second jig attached to the second movable element, the device comprising: a storage unit that stores a table in which first position information representing a set position in the transport path and second position information indicating the position of the second movable element when the distance between the first jig and the second jig is a preset distance when the first movable element is at the set position, are associated with each other; a first position command generation unit that generates a first position command for moving the first movable element; and a second position command generation unit that generates a second position command for moving the second movable element to a position determined based on the position of the first movable element and the table.

2. The control device according to claim 1, characterized in that the second position command generation unit determines a position to move the second movable element by interpolating the second position information read from the table, and generates a second position command for moving the second movable element to the determined position.

3. The control device according to claim 1 or 2, characterized in that the table stores second position information calculated in advance based on a preset distance value, a value indicating the offset of the control point of the first jig from the control point of the first movable element, a value indicating the offset of the control point of the second jig from the control point of the second movable element, coordinates indicating a position set in the transport path, and the angle of the tangent to the line representing the transport path at the position indicated by the coordinates.

4. The control device according to any one of claims 1 to 3, wherein the transport path includes a straight section and a curved section, the table stores the first position information representing each of a plurality of positions set in the transport path, and the plurality of positions are set to be more densely located in the curved section than in the straight section.

5. The control device according to any one of claims 1 to 3, wherein the transport path includes a straight section and a curved section, the table stores the first position information representing each of a plurality of positions set in the transport path, and the plurality of positions are set to be denser in a second section of the transport path where at least one of the positions indicated by the first position information and the positions indicated by the second position information is included in the curved section than in a first section of the transport path where both the positions indicated by the first position information and the positions indicated by the second position information are included in the straight section.

6. The control device according to any one of claims 1 to 3, characterized in that, for a region of the transport path, the first position information and the second position information are set such that the distance between the first jig and the second jig is a first distance, and for a region of the transport path other than the region, the first position information and the second position information are set such that the distance between the first jig and the second jig is a second distance different from the first distance.

7. The control device according to any one of claims 1 to 6, characterized in that the second position command generation unit generates a second position command based on the first position command and the table.

8. The control device according to any one of claims 1 to 6, characterized in that the second position command generation unit generates the second position command based on the result of detecting the position of the first movable element and the table.

9. The control device according to any one of claims 1 to 6, characterized in that the second position command generation unit generates the second position command based on the result of processing the first position command with a filter having low-pass characteristics, or the result of processing the position of the first movable element with a filter having low-pass characteristics, and the table.

10. The control device according to any one of claims 1 to 9, comprising a table generation unit that generates the table, wherein the storage unit stores the table generated by the table generation unit.

11. A conveying system comprising: a linear motor conveying device that conveys an object held by a first jig attached to the first movable element and a second jig attached to the second movable element, the stator provided on the conveying path and a first movable element and a second movable element that move along the conveying path; and a control device that controls the linear motor conveying device, wherein the control device comprises: a storage unit that stores a table in which first position information representing a set position on the conveying path and second position information indicating the position of the second movable element when the distance between the first jig and the second jig is a preset distance when the first movable element is at the set position, a first position command generation unit that generates a first position command for moving the first movable element; and a second position command generation unit that generates a second position command for moving the second movable element to a position determined based on the position of the first movable element and the table.

12. The transport system according to claim 11, comprising a table generation device for generating the table, wherein the storage unit stores the table generated by the table generation device.

13. A control method for controlling a linear motor transport device by a computer system, the device comprising a stator provided on a transport path, a first movable element and a second movable element that move along the transport path, and a transport object held by a first jig attached to the first movable element and a second jig attached to the second movable element, the control method comprising: a step of generating a first position command for moving the first movable element; and a step of generating a second position command for moving the second movable element to a position determined based on a table and the position of the first movable element, wherein first position information representing a position set on the transport path and second position information indicating the position of the second movable element when the distance between the first jig and the second jig is a preset distance when the first movable element is at the set position are associated with each other.

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