Conveyance system and control device

Abstract

A conveyance system (10) comprises: a drive unit (20A) that supplies a drive current to a plurality of coils (9A1-9A5) disposed along a conveyance path (8); a thrust command generation unit (15) that generates a thrust command, which is a command value for a thrust generated in the movable element (4A) on the basis of an operation target value, which is a target value for time-series operation; and a current command generation unit (13') that generates, as a current command, a current target value, which is a target value for the drive current to be applied to the plurality of coils (9A1-9A5) so that the thrust generated by the movable element (4) follows the thrust command. The current command generation unit (13') generates, so as to reduce the number of coils through which the drive current flows, the current target value to be applied to the plurality of coils (9A1-9A5) by using a part of actual thrust characteristics determined by the characteristics of the plurality of coils (9A1-9A5) and the movable element (4A).

Description

Conveyance system and control device

[0001] The present disclosure relates to a transport system that transports objects and a control device provided in the transport system.

[0002] In production lines where factory automation is implemented, such as production lines for assembling industrial products or for packaging food, conveyance systems for transporting workpieces are commonly used. In recent years, conveyance systems have been widely used in which the conveyance path for transporting the workpieces is divided into multiple zones, and carts carrying the workpieces are driven by control devices located in each zone. This type of conveyance system is one of the conveyance systems that excels in terms of production efficiency.

[0003] One type of conveyance system utilizes a so-called moving magnet linear motor, in which a magnet is arranged on a carriage, which is the mover, and a coil is arranged on a stator that forms the conveyance path. Moving magnet linear motors are more suitable for long-distance conveyance than moving coil linear motors, which use a coil as the mover. On the other hand, when a moving magnet linear motor requires conveyance over a long distance relative to the size of the mover, multiple coils are required according to the conveyance distance. Furthermore, conveyance systems using moving magnet linear motors are required to be able to individually control multiple carriages, and to be able to control the movement of the carriages with high precision even when multiple carriages are adjacent to each other.

[0004] Patent Document 1 below discloses a conveyance system using a linear motor. The conveyance system disclosed in Patent Document 1 includes a carriage having a magnet and multiple coil units arranged on a conveyance path. Each coil unit includes multiple coils. The conveyance system disclosed in Patent Document 1 generates thrust to move the carriage through the interaction between the current flowing through the coils and the magnetic field generated by the magnet. The conveyance system includes a control unit, which determines the ratio of current supplied to each coil unit based on the positions of the multiple carriages and the impedance and thrust characteristics of each of the multiple coil units. Patent Document 1 states that the carriage can be controlled with high precision even when controlled by multiple coil units.

[0005] Japanese Patent Application Laid-Open No. 2017-79569

[0006] The transportation system disclosed in Patent Document 1 includes a switch separate from a current control unit that controls the current flowing through the coil. Furthermore, the transportation system disclosed in Patent Document 1 requires the generation and output of an opening / closing command to control the switch. Therefore, the transportation system disclosed in Patent Document 1 has a problem in that the circuit configuration becomes more complex due to the need for a switch. Furthermore, the transportation system disclosed in Patent Document 1 requires the generation and output of an opening / closing command separate from the current command, which complicates the process for controlling the transportation system.

[0007] The present disclosure has been made in view of the above, and aims to provide a transport system that can simplify the circuit configuration and enable control through simple processing.

[0008] In order to solve the above-mentioned problems and achieve the object, a conveyance system according to the present disclosure is a conveyance system including a mover and a conveyance path along which the mover moves, and further including a drive unit, a thrust command generation unit, and a current command generation unit. The drive unit supplies drive currents to multiple coils arranged along the conveyance path. The thrust command generation unit generates a thrust command, which is a command value for a thrust to be generated by the mover, based on an operation target value, which is a target value for a time-series operation input from an external device or generated internally. The current command generation unit generates, as a current command, a current target value, which is a target value for a drive current to be applied to the multiple coils so that the thrust generated by the mover follows the thrust command. The current command generation unit generates a current target value to be applied to the multiple coils using a portion of the actual thrust characteristics determined by the characteristics of the multiple coils and the mover, so as to reduce the number of coils through which the drive current flows.

[0009] The transport system according to the present disclosure has the advantage that the circuit configuration can be simplified and control can be achieved through simple processing.

[0010] FIG. 1 is a diagram showing an example of the configuration of a conveyance system according to embodiment 1; FIG. 2 is a diagram showing an example of the configuration of a control device and a drive device according to embodiment 1; FIG. 3 is a diagram used to explain the problem in embodiment 1; FIG. 4 is a diagram used to explain the effect when a current command is generated using the corrected thrust coefficient distribution shown in FIG. 4; FIG. 5 is a diagram showing an example of the configuration of a control device according to a first modified example of embodiment 1; FIG. 6 is a diagram showing an example of the configuration of a control device according to a second modified example of embodiment 1; FIG. 7 is a diagram used to explain the problem in embodiment 2;

[0011] A conveyance system and a control device according to an embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. In the following description, multiple components of the same type are denoted by reference numerals with subscripts, but when describing these components without distinguishing between them, the subscripts will be omitted as appropriate.

[0012] First Embodiment A conveyance system according to a first embodiment is a system used to convey an object. The conveyance system conveys the object by moving a mover on which the object is placed. An example of the mover is a cart.

[0013] FIG. 1 is a diagram showing an example of the configuration of a conveyance system 10 according to the first embodiment. As shown in FIG. 1, the conveyance system 10 according to the first embodiment includes a control device 1, drive devices 2A, 2B, 2C, 2D, 2E, 2F, 2G, and 2H (hereinafter referred to as "2A to 2H" as appropriate, and the same applies to other reference symbols), coil units 3A to 3H, movers 4A to 4C, and scale heads 5A to 5C. Furthermore, as shown in FIG. 2, the conveyance system 10 according to the first embodiment also includes linear scales 6A and 6B. Although not shown in FIG. 2, the drive devices 2C to 2H also include linear scales.

[0014] The plurality of driving devices 2 are connected to one another. In the conveying system 10, the plurality of driving devices 2 are connected to one another to form a conveying path 8 along which the mover 4 moves. The plurality of driving devices 2 apply current to the coil unit 3 to generate thrust in the mover 4, thereby moving the mover 4.

[0015] 1 shows a closed circular path, but is not limited to this example. The transport path 8 of the transport system 10 may be an open path. That is, the transport path 8 of the transport system 10 may be a path having a start point and an end point.

[0016] The driving devices 2A, 2B, 2E, and 2F are linear driving devices 2 that form a linear path. The driving devices 2C, 2D, 2G, and 2H are curved driving devices 2 that form a curved path and change the traveling direction of the mover 4. The conveying path 8 may not have linear driving devices 2 and may be composed only of curved driving devices 2. In other words, the overall shape of the conveying path 8 is arbitrary.

[0017] The conveying system 10 according to the first embodiment is a moving magnet type linear motor. The mover 4 moves along a guide rail (not shown) provided on the side of the conveying path 8. The mover 4 includes a permanent magnet (not shown) and is attached to the side of the conveying path 8. The mover 4 also includes a guide roller (not shown) that moves on the guide rail by rotation. The mover 4 moves on the side of the conveying path 8 and stops at the side of the conveying path 8. The guide roller may also be provided on the upper surface of the conveying path 8.

[0018] The direction of travel of each mover 4 is either clockwise in Fig. 1 or counterclockwise in Fig. 1. Of the travel directions, the clockwise direction in Fig. 1 is referred to as the forward direction. Of the travel directions, the counterclockwise direction in Fig. 1 is referred to as the reverse direction. Arrow 17A represents the forward direction, and arrow 17B represents the reverse direction.

[0019] 1 , the conveying system 10 includes eight driving devices 2 and three movers 4. The number of driving devices 2 included in the conveying system 10 is arbitrary. That is, the number of driving devices 2 that configure the conveying path 8 is arbitrary, and the number of movers 4 that move on the conveying path 8 is also arbitrary. Furthermore, the number of movers 4 that move on the conveying path 8 may be one.

[0020] The control device 1 is connected to each of the drive devices 2 via a data communication line 7. The control device 1 controls each of the multiple drive devices 2. The data communication line 7 is composed of a communication line connecting the control device 1 to one of the multiple drive devices 2, and a communication line connecting adjacent drive devices 2. That is, the conveyance system 10 is configured such that the control device 1 is connected to each of the drive devices 2 via a daisy chain connection. Note that the connection between the control device 1 and each of the drive devices 2 is not limited to a daisy chain connection. The connection between the control device 1 and each of the drive devices 2 may also be a star connection in which each drive device 2 is connected to the control device 1 via a communication hub. Alternatively, the conveyance system 10 may be configured such that the control device 1 is provided with multiple data communication lines 7, and the control device 1 and each of the drive devices 2 are directly connected by the data communication lines 7. Furthermore, the data communication line 7 may not be a physical communication line, but may be a communication path capable of wireless communication.

[0021] Next, the configurations and functions of the control device 1 and the drive device 2 will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the configuration of the control device 1 and the drive device 2 according to the first embodiment.

[0022] The upper left side of Fig. 2 shows a driving device 2A, a coil unit 3A, a mover 4A, a scale head 5A, and a linear scale 6A. The right side of Fig. 2 shows a driving device 2B, a coil unit 3B, a mover 4B, a scale head 5B, and a linear scale 6B. The lower left side of Fig. 2 shows a control device 1.

[0023] The drive device 2A includes a drive unit 20A, a data communication unit 21A, a detector communication unit 24A, and a current detector 23A. The drive unit 20A includes a plurality of current control units 22A, and the coil unit 3A includes a plurality of coils 9A connected one-to-one to the current control units 22A of the drive unit 20A. As shown in FIG. 1, the plurality of coils 9A are arranged along the conveying path 8. As shown in FIG. 2, the plurality of coils 9A are single-phase coils. Like the drive device 2A, the drive device 2B also includes a drive unit 20B, a data communication unit 21B, and a detector communication unit 24B.

[0024] The mover 4A includes a permanent magnet 40. The permanent magnet 40 included in the mover 4A is a permanent magnet that contributes to driving the mover 4A.

[0025] As described with reference to FIG. 1 , drive devices 2A, 2B, 2E, and 2F are all linear drive devices 2. On the other hand, drive devices 2C, 2D, 2G, and 2H are curved drive devices 2. However, the configuration of the curved drive devices 2 is the same as that of the linear drive device 2, except for the arrangement of the coils 9, which is different from that of the linear drive device 2. Therefore, the following description will focus on drive device 2A, which is a linear drive device 2. However, the content described below is not limited to the linear drive device 2.

[0026] In FIG. 2, the five coils 9A in the coil unit 3A are labeled 9A1 to 9A5, and the five current control units 22A in the drive unit 20A are labeled 22A1 to 22A5. The five coils 9A labeled 9A1 to 9A5 are located within a range affected by the magnetic field emitted from the permanent magnet 40 of the mover 4A, and contribute to driving the mover 4A. The five current control units 22A labeled 22A1 to 22A5 are connected to the coils 9A labeled 9A1 to 9A5. When the positional relationship between the mover 4A and the coil unit 3A is as shown in FIG. 2, the coils 9A farther from the mover 4A do not significantly contribute to driving the mover 4A. In the first embodiment, the coils 9A1 to 9A5 are described as the coils that contribute to driving the mover 4A. Driving currents are supplied to the coils 9A1 to 9A5 by current control units 22A1 to 22A5, which are connected one-to-one to each other. The number of coils 9 that contribute to driving one mover 4 is determined by the number of coils 9 that are arranged in an area that is affected by the size of the permanent magnet 40 of the mover 4, the strength of the magnetic field, and the like. The number of coils 9A that drive one mover 4A described here is an example and is not limited to this example. In other words, the number of coils 9A that contribute to driving one mover 4A may be any number other than five.

[0027] A scale head 5A is attached to the mover 4A. The scale head 5A moves on a linear scale 6A together with the mover 4A. The linear scale 6A detects position information of the mover 4A and transmits it to a detector communication unit 24A of the drive device 2. Specifically, the linear scale 6A detects a motion detection value yA such as the position and speed of the mover 4A from the position of the scale head 5A connected to the mover 4A, and transmits the detected motion detection value yA to the detector communication unit 24A. The scale head 5A can be composed of, for example, a permanent magnet for position detection, and the linear scale 6A can be composed of a sensor element that detects the magnetic field of the position detection magnet.

[0028] The control device 1 includes an operation target value generating unit 11, a position and speed control unit 12, a current command generating unit 13, and a data communication unit 14. The operation target value generating unit 11 and the position and speed control unit 12 constitute a thrust command generating unit 15.

[0029] The data communication unit 14 and data communication unit 21A are connected by communication line 7A, and the data communication unit 21A and data communication unit 21B are connected by communication line 7B. This connection is the daisy chain connection described above, and the communication data TxRx exchanged between the data communication unit 14 and data communication unit 21A includes not only information about the drive unit 2A but also information about the drive units 2B to 2H. The data communication unit 21A of the drive unit 2A transmits the communication data TxRx received from the data communication unit 14 to the data communication unit 21B of the drive unit 2B. Similarly, the data communication unit 21B transmits the received communication data TxRx to the drive unit 2C (not shown in FIG. 2 ) described below.

[0030] The data communication unit 14 receives information about the motion detection value y via the data communication unit 21A of the drive device 2A. The motion detection value y received by the data communication unit 14 includes not only the motion detection value yA of the mover 4A but also the motion detection values ​​of the movers 4B and 4C.

[0031] The thrust command generator 15 generates a thrust command τref, which is a command value for the thrust to be generated in the mover 4, based on a motion target value yref, which is a time-series motion target value generated by the motion target value generator 11, and a motion detection value y, which represents the motion position or motion speed of the mover 4. Specifically, the position and speed controller 12 generates the thrust command τref so that the motion detection value y follows the motion target value yref. Like the motion detection value y, the motion target value yref includes motion target values ​​for all movers 4A to 4C present in the conveyance system 10. Furthermore, the thrust command τref is generated for each mover 4 and includes thrust commands for all movers 4A to 4C. Note that, although FIG. 2 illustrates a configuration in which the motion target value yref is generated inside the control device 1, this configuration is not limiting. The motion target value yref may also be input to the control device 1 from outside.

[0032] The current command generation unit 13 generates, as a current command Iref, a current target value that is a target value of the drive current to be applied to the plurality of coils 9, based on the thrust command τref and the motion detection value y that indicates the motion position or motion speed of the mover 4. A specific method for generating the current command Iref will be described later. Information related to the generated current command Iref is transmitted to the data communication unit 21A by the data communication unit 14.

[0033] Data communication unit 21A of drive unit 2A extracts current commands IrefA1 to IrefA5, which are current commands for drive unit 2A, from communication data TxRx transmitted from data communication unit 14, and outputs the extracted current commands IrefA1 to IrefA5 to current control units 22A1 to 22A5. It goes without saying that communication data TxRx transmitted from data communication unit 14 includes the current commands Iref for drive units 2B to 2H.

[0034] Current detectors 23A1-23A5 detect currents IA1-IA5 flowing through coils 9A1-9A5. Current control units 22A1-22A5 acquire current commands IrefA1-IrefA5 from data communication unit 21A, acquire operation detection value yA from detector communication unit 24A, and acquire detection values ​​of currents IA1-IA5 from current detectors 23A1-23A5. Current control units 22A1-22A5 control currents IA1-IA5, which are drive currents applied to coils 9A1-9A5, so that the detection values ​​of currents IA1-IA5 follow current commands IrefA1-IrefA5. Note that any method for controlling currents IA1-IA5 may be used.

[0035] Next, detailed operation of the current command generating unit 13 included in the control device 1 according to the first embodiment will be described with reference to FIGS. 3 to 5. FIG. 3 is a diagram illustrating a problem in the first embodiment. FIG. 4 is a diagram illustrating a corrected thrust coefficient distribution used in the current command generating unit 13 according to the first embodiment. FIG. 5 is a diagram illustrating the effect when a current command Iref is generated using the corrected thrust coefficient distribution shown in FIG. 4. FIGS. 3 and 5 are diagrams illustrating the control device 1, drive unit 2A, coil unit 3A, mover 4A, scale head 5A, and linear scale 6A extracted from FIG. 2, and components that are the same as or equivalent to those in FIG. 2 are denoted by the same reference numerals. Note that in the following description, portions that overlap with the above content will be omitted as appropriate.

[0036] As described above, the current command generation unit 13 generates the current command IrefA based on the thrust command τref and the motion detection value y of the mover 4. Specifically, the current command generation unit 13 calculates current commands IrefA1 to IrefA5, which are target values ​​of drive currents to be applied to the coils 9A1 to 9A5, using the following equation (1). Note that the current command generation unit 13 calculates the current command Iref for each of the coils 9 in each coil unit 3 included in the transportation system 10, but for convenience, the calculation of five current commands IrefA1 to IrefA5 will be described here.

[0037] IrefA1=KA1 / (KA1^2+KA2^2+KA3^2+KA4^2+KA5^2)×τref IrefA2=KA2 / (KA1^2+KA2^2+KA3^2+KA4^2+KA5^2)×τref IrefA3=KA3 / (KA1^2+KA2^2+KA3^2+KA4^2+KA5^2)×τref IrefA4=KA4 / (KA1^2+KA2^2+KA3^2+KA4^2+KA5^2)×τref IrefA5=KA5 / (KA1^2+KA2^2+KA3^2+KA4^2+KA5^2)×τref...Formula (1)

[0038] In equation (1), KA1 to KA5 are coefficients that represent the magnitude of thrust generated in response to currents IA1 to IA5 flowing through coils 9A1 to 9A5. In this paper, these coefficients are referred to as "thrust coefficients."

[0039] FIG. 3 shows the waveform of the actual thrust coefficient distribution KA(x). The actual thrust coefficient distribution KA(x) is a waveform that represents the relationship between the mover position, which indicates the distance from the center position of the mover 4, and the thrust coefficient. The horizontal axis of the graph showing the waveform of the actual thrust coefficient distribution KA(x) represents the mover position and is the axis that coincides with the thrust coefficient "0 (zero)." This also applies to the following figures. The thrust coefficients KA1 to KA5 in the above equation (1) can be obtained from the actual thrust coefficient distribution KA(x) shown in FIG. 3. The actual thrust coefficient distribution KA(x) is an actual thrust characteristic determined by the characteristics of the coil 9 and the mover 4. Here, the characteristics of the coil 9 that determine the actual thrust characteristic include the number of windings of the coil 9, the radius of the coil winding, etc., and the characteristics of the mover 4 include the magnetic flux and magnetic pole pitch of the permanent magnet 40 provided in the mover 4.

[0040] The thrust coefficients KA1 to KA5 in the actual thrust coefficient distribution KA(x) have the same values ​​as the induced voltage coefficients that represent the relationship between the mover position and the induced voltages generated in the coils 9A1 to 9A5 when the mover 4 moves. For this reason, this paper uses the actual thrust coefficient distribution KA(x) created using the induced voltages generated in the coils 9A1 to 9A5 when the mover 4 moves.

[0041] According to the calculation formula (1), when the thrust coefficients KA1 to KA5 are 0, a current command IrefA of 0 [A] is generated. The current command IrefA of 0 [A] is input to the current control unit 22A via the data communication units 14 and 21A. The current control unit 22A controls the current flowing through the coil 9A to 0 [A]. As a result, no drive current flows through the coil 9A to which the current command IrefA of 0 [A] is commanded.

[0042] On the other hand, when the thrust coefficients KA1 to KA5 are not 0, a current command IrefA other than 0 [A] is generated. The current command IrefA other than 0 [A] is input to the current control unit 22A via the data communication units 14, 21A. The current control unit 22A controls the current flowing through the coil 9A to a value other than 0 [A]. As a result, a drive current flows through the coil 9A to which the current command IrefA other than 0 [A] is commanded.

[0043] As can be understood from the above explanation, when the calculation formula (1) is used, the drive current flowing through coil 9A depends on the actual thrust coefficient distribution KA(x) of the mover 4. For this reason, when the actual thrust coefficient distribution KA(x) shown in FIG. 3 is used, it is not possible to freely change the number of coils through which the drive current flows.

[0044] Therefore, in the first embodiment, the corrected thrust coefficient distribution K'A(x) shown in FIG. 4 is used instead of the actual thrust coefficient distribution KA(x) shown in FIG. 3 . In FIG. 4 , the actual thrust coefficient distribution KA(x) shown in FIG. 3 is indicated by a dashed line, and the corrected thrust coefficient distribution K'A(x) is indicated by a solid line. Furthermore, FIG. 5 shows an example configuration of a control device 1' that uses the corrected thrust coefficient distribution K'A(x). In FIG. 5 , the current command generation unit 13 shown in FIG. 3 is replaced with a current command generation unit 13'. Furthermore, in FIG. 5 , the current command IrefA (IrefA1 to IrefA5) input to the current control unit 22A is set to the current command Iref'A (Iref'A1 to Iref'A5). In other words, the current command generation unit 13' generates the current command Iref'A, which is the current target value, using a portion of the actual thrust characteristic determined by the characteristics of the coil 9 and the mover 4. In FIG. 5, the same or equivalent parts as those in FIG. 3 are denoted by the same reference numerals, and duplicated explanations will be omitted where appropriate.

[0045] Iref'A1=K'A1 / (K'A1^2+K'A2^2+K'A3^2+K'A4^2+K'A5^2)×τref Iref'A2=K'A2 / (K'A1^2+K'A2^2+K'A3^2+K'A4^2+K'A5^2)×τref Iref'A3=K'A3 / (K'A1^2+K'A2^2+K'A3^2+K'A4^2+K'A5^2)×τref Iref'A4=K'A4 / (K'A1^2+K'A2^2+K'A3^2+K'A4^2+K'A5^2)×τref Iref'A5=K'A5 / (K'A1^2+K'A2^2+K'A3^2+K'A4^2+K'A5^2)×τref...Formula (2)

[0046] In equation (2), K'A1 to K'A5 are thrust coefficients calculated from the corrected thrust coefficient distribution K'A(x). The corrected thrust coefficient distribution K'A(x) is a waveform representing a corrected thrust characteristic created using a portion of the actual thrust coefficient distribution KA(x), which is an actual thrust characteristic determined by the characteristics of the multiple coils 9 and the mover 4. In Fig. 5, the corrected thrust coefficient distribution K'A(x) is created by extracting a portion of the actual thrust coefficient distribution KA(x), which is determined by the characteristics of the coils 9A1 to 9A5 and the mover 4A.

[0047] Specifically, in the corrected thrust coefficient distribution K'A(x) of Fig. 5, the value of the thrust coefficient K'A1 corresponding to coil 9A1 and the value of the thrust coefficient K'A5 corresponding to coil 9A5 are set to "0". Therefore, when the current command Iref'A1, which is the target value of the drive current to be applied to coil 9A1, and the current command Iref'A5, which is the target value of the drive current to be applied to coil 9A5, are calculated using equation (2), the current command is 0 [A]. As a result, the number of coils 9A through which the drive current flows is reduced from five to three.

[0048] The corrected thrust coefficient distribution K'A(x) shown in FIGS. 4 and 5 is an example, and the present invention is not limited to the waveforms shown in these figures.

[0049] As described above, by using the control device 1' according to embodiment 1, it is possible to reduce the number of coils through which drive current flows, without connecting switches to multiple coils 9 as in Patent Document 1.

[0050] Next, a modified configuration of the control device 1' according to the first embodiment will be described. FIG. 6 is a diagram showing an example of the configuration of a control device 1" according to a first modified example of the first embodiment. In FIG. 6, the thrust command generation unit 15 shown in FIG. 5 is replaced with a thrust command generation unit 15", the operation target value generation unit 11 shown in FIG. 5 is replaced with an operation target value generation unit 11", and the current command generation unit 13' shown in FIG. 5 is replaced with a current command generation unit 13". Furthermore, the position and speed control unit 12 that was present in FIG. 5 is omitted in FIG. 6. In FIG. 6, parts that are the same as or equivalent to those in FIG. 5 are designated by the same reference numerals, and duplicated explanations will be omitted as appropriate.

[0051] In FIG. 6, if the motion target value yref generated by the motion target value generation unit 11'' can be regarded as a thrust command τref, the motion target value generation unit 11 can be configured as a thrust command generation unit 15'' as shown in FIG. 6, and the thrust command τref output from the thrust command generation unit 15'' can be input to the current command generation unit 13''. The current command generation unit 13'' generates a current command Iref'' using the thrust command τref and outputs it to the data communication unit 14. The current control unit 22A receives the current commands Iref''A (Iref''A1 to Iref''A5) via the data communication units 14 and 21A. The current control unit 22A controls the currents IA1 to IA5, which are the drive currents applied to the coils 9A1 to 9A5, so that the detected values ​​of the currents IA1 to IA5 follow the Iref''A1 to Iref''A5.

[0052] The control device 1' according to the first embodiment may also be configured as shown in FIG. 7. FIG. 7 is a diagram showing a configuration example of a control device 1''' according to a second modification of the first embodiment. In FIG. 7, the thrust command generator 15 shown in FIG. 5 is replaced with a thrust command generator 15'''. The position and speed control unit 12 and the current command generator 13' shown in FIG. 5 are moved to the drive unit 2A in FIG. 7 and configured as a position and speed control unit 25A''' and a current command generator 26A'''. Also, in FIG. 7, the operation target value generator 11 shown in FIG. 5 is replaced with an operation target value generator 11'''. That is, in FIG. 7, the operation target value generator 11''' and the position and speed control unit 25A''', which are components of the thrust command generator 15''', are separately arranged in the control device 1''' and the drive unit 2A''''. Furthermore, in Fig. 7, the data communication unit 14 shown in Fig. 5 is replaced with a data communication unit 14''', and the data communication unit 21A shown in Fig. 5 is replaced with a data communication unit 21A'''. In Fig. 7, parts that are the same as or equivalent to those in Fig. 5 are denoted by the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0053] In FIG. 7 , the motion target value yref generated by the motion target value generation unit 11''' is output to the data communication unit 14 and transmitted to the drive device 2A. The position and speed control unit 25A''' receives information on the motion target value yref via the data communication unit 21A'''. The position and speed control unit 25A''' generates a thrust command τref so that the motion detection value y follows the motion target value yref, and outputs the thrust command τref to the current command generation unit 26A'''. The current command generation unit 26A''' generates a current command Iref'''A (Iref'''A1 to Iref'''A5) based on the thrust command τref and the motion detection value yA of the mover 4A, and outputs the current command Iref'''A to the current control unit 22A. The current control unit 22A controls the currents IA1 to IA5, which are drive currents applied to the coils 9A1 to 9A5, so that the detected values ​​of the currents IA1 to IA5 follow the current commands Iref''A1 to Iref''A5.

[0054] As described above, the conveying system according to the first embodiment includes a mover and a conveying path along which the mover moves. The conveying system includes a driving unit that supplies drive currents to multiple coils arranged along the conveying path, and a thrust command generating unit that generates thrust commands, which are command values ​​for thrust to be generated by the mover, based on an externally input or internally generated time-series operation target value. The conveying system also includes a current command generating unit that generates current target values, which are target values ​​for drive currents to be applied to the multiple coils so that the thrust generated by the mover follows the thrust command. The current command generating unit generates current target values ​​to be applied to the multiple coils using a portion of actual thrust characteristics determined by the characteristics of the multiple coils and the mover, so as to reduce the number of coils through which drive current flows. This conveying system configured in this manner can reduce the number of coils through which drive current flows without connecting switches to the multiple coils, as in Patent Document 1. This enables a conveying system with a simplified circuit configuration and control through simple processing.

[0055] The control device according to the first embodiment is applicable to a conveyance system including a mover, a conveyance path along which the mover moves, and a drive device that supplies drive current to multiple coils arranged along the conveyance path. The control device includes a thrust command generation unit that generates a thrust command, which is a command value for a thrust to be generated by the mover, based on an externally input or internally generated time-series operation target value. The control device also includes a current command generation unit that generates current target values, which are target values ​​for drive current to be applied to the multiple coils so that the thrust generated by the mover follows the thrust command. The current command generation unit generates current target values ​​to be applied to the multiple coils using a portion of actual thrust characteristics determined by the characteristics of the multiple coils and the mover, so as to reduce the number of coils through which drive current flows. This control device can reduce the number of coils through which drive current flows without connecting switches to the multiple coils, as in Patent Document 1. This makes it possible to obtain a control device with a simplified circuit configuration and control through simple processing.

[0056] Embodiment 2 In embodiment 2, a transport system and a control device that can solve the problem in embodiment 1 while also solving another problem will be described. Figure 8 is a diagram used to explain the problem in embodiment 2. In Figure 8, components that are the same as or equivalent to those in Figure 3 are denoted by the same reference numerals. In the following description, parts that overlap with the above content will be omitted as appropriate.

[0057] Fig. 8 shows a situation in which multiple movers 4 are adjacent to each other on linear scale 6A, and shows mover 4A and the adjacent mover 4B. Also in Fig. 8, the waveform of the actual thrust coefficient distribution KA(x) using the characteristics of mover 4A is shown by a solid line, and the waveform of the actual thrust coefficient distribution KB(x) using the characteristics of mover 4B is shown by a dashed line. The actual thrust coefficient distribution KA(x) is used when generating the current command Iref for coil 9 that supplies a drive current to drive mover 4A, and the actual thrust coefficient distribution KB(x) is used when generating the current command Iref for coil 9 that supplies a drive current to drive mover 4B.

[0058] As shown in Figure 8, when movers 4A and 4B are adjacent to each other, the coils 9 that drive these movers 4A and 4B are also adjacent to each other. In other words, the multiple coils 9A that drive mover 4A (the "first coil group" described below) and the multiple coils 9B that drive mover 4B (the "second coil group" described below) are adjacent to each other. In this paper, "adjacent" refers to a situation in which, as shown in Figure 8, the right-side coils 9A4 and 9A5 of the coil group 9A1 to 9A5 that drives one mover, mover 4A, overlap with the left-side coils 9B1 and 9B2 of the coil group 9B1 to 9B5 (coils 9B3 to 9B5 are not shown) that drives the other mover, mover 4B. In this case, the thrust coefficients KA4 and KA5 used when generating current commands IrefA4 and A5 for coils 9A4 and 9A5 when driving the mover 4A overlap with the thrust coefficients KB1 and KB2 used when generating current commands IrefB1 and B2 for coils 9B1 and 9B2 when driving the mover 4B, so this situation can also be considered adjacent.

[0059] In this paper, any one of the multiple movers 4 may be referred to as a "first mover," and a coil group consisting of multiple coils 9 that drive the first mover may be referred to as a "first coil group." Also, a mover 4 adjacent to the first mover may be referred to as a "second mover," and a coil group consisting of multiple coils 9 that drive the second mover may be referred to as a "second coil group."

[0060] Specifically, the current command IrefA5 for coil 9A4 and the current command IrefB2 for coil 9B1, which is the same coil, can be expressed as the following equations (3) and (4) using the above equation (1).

[0061] IrefA5=KA5 / (KA1^2+KA2^2+KA3^2+KA4^2+KA5^2)×τrefA...Formula (3) IrefB2=KB2 / (KB1^2+KB2^2+KB3^2+KB4^2+KB5^2)×τrefB...Formula (4)

[0062] In the above equations (3) and (4), τrefA is a thrust command for mover 4A, and τrefB is a thrust command for mover 4B. Because the thrust commands τrefA and τrefB change over time, the current command IrefA5 for the overlapping coil 9A5 and the current command IrefB2 for the overlapping coil 9B2 do not always match. If these current commands IrefA5 and IrefB2 do not match, when the current command IrefA5 calculated from equation (3) is input to the current control unit 22A5 that supplies a drive current to the coil 9A5 (9B2), the thrust generated in the mover 4B will not match the thrust command τrefB. Similarly, when the current command IrefB2 calculated from equation (4) is input to the current control unit 22A5, the thrust generated in the mover 4A will not match the thrust command τrefA. In this way, when the current command Iref is calculated using the actual thrust coefficient distributions KA(x) and KB(x), if multiple movers 4 are adjacent to each other, there is a possibility that some movers 4 will not be able to generate thrust in accordance with the thrust command τref, which poses a problem in that it is difficult to control all of the movers with high precision.

[0063] To solve this problem, in the second embodiment, the control device 1' described in the first embodiment is used, and the mover 4 is driven using the corrected thrust coefficient distribution K'A(x) proposed in the first embodiment.

[0064] Next, the operation of the control device 1' according to the second embodiment will be described. Fig. 9 is a diagram illustrating the operation of the control device 1' according to the second embodiment. In Fig. 9, components that are the same as or equivalent to those in Fig. 5 are denoted by the same reference numerals. In the following description, parts that overlap with the above content will be omitted as appropriate.

[0065] 9, the waveform of the corrected thrust coefficient distribution K'A(x) is shown by a solid line, and the waveform of the corrected thrust coefficient distribution K'B(x) is shown by a dashed line. The corrected thrust coefficient distribution K'A(x) is used when generating a current command Iref for the coil 9 that supplies a drive current to drive the mover 4A, and the corrected thrust coefficient distribution K'B(x) is used when generating a current command Iref for the coil 9 that supplies a drive current to drive the mover 4B.

[0066] 9 , when movers 4A and 4B are adjacent to each other, the coils 9 that drive these movers 4A and 4B are also adjacent to each other. On the other hand, when corrected thrust coefficient distributions K'A(x) and K'B(x) are used, there is no case in which the value of the thrust coefficient K'A in the corrected thrust coefficient distribution K'A(x) and the value of the thrust coefficient K'B in the corrected thrust coefficient distribution K'B(x) are both non-zero. In other words, at least one of the value of the thrust coefficient K'A in the corrected thrust coefficient distribution K'A(x) and the value of the thrust coefficient K'B in the corrected thrust coefficient distribution K'B(x) is always zero. As a result, even when movers 4A and 4B are adjacent to each other, an appropriate thrust command τref can be given to movers 4A and 4B, making it possible to control movers 4A and 4B with high precision.

[0067] 9 has been described in connection with a case where two movers 4A and 4B are adjacent, but this is not limiting. The same explanation can be given for a case where movers 4B and 4C are adjacent, or a case where movers 4A and 4C are adjacent. Furthermore, while FIG. 9 has been described in connection with a case where two movers 4A and 4B are adjacent, the same explanation can be given for a case where three or more movers 4 are adjacent.

[0068] By using the method of the second embodiment, it is possible to always calculate the current command Iref' using equation (2) and the corrected thrust coefficient distributions K'A(x) and K'B(x), regardless of the adjacent state of multiple movers 4. Therefore, by using the method of the second embodiment, it is possible to calculate the current command Iref' using only simple arithmetic operations, and complex calculations such as simultaneous equations are not required. This reduces the amount of calculation and has the effect of lightening the calculation load.

[0069] Furthermore, in the method of the second embodiment, the current command Iref' can be calculated using the same calculation formula (2) for all of the multiple movers 4, so the corrected thrust coefficient distribution K'(x) can be set to the same value for all of the multiple movers 4. As a result, the thrust command generated for all of the movers 4 becomes the same value, and an effect is obtained in which the same control can be performed for all of the movers 4.

[0070] As described above, in the conveying system and control device according to the second embodiment, the current command generation unit generates a current target value to be applied to the coils of the first coil group using a portion of the actual thrust force characteristics determined by the characteristics of the coils of the first coil group and the first mover driven by the first coil group. The current command generation unit also generates a current target value to be applied to the coils of the second coil group using a portion of the actual thrust force characteristics determined by the characteristics of the coils of the second coil group and the second mover driven by the second coil group. The first coil group here refers to a coil group consisting of multiple coils that drive the first mover, and the second coil group refers to a coil group consisting of multiple coils that drive the second mover and is adjacent to the first coil group. By using a corrected thrust coefficient distribution created using a portion of the actual thrust force characteristics rather than the entire actual thrust force characteristics, it is possible to avoid different thrust commands being applied to the same coil that can control different movers when multiple movers are adjacent to each other. This allows appropriate thrust commands to be given to multiple movers even when they are adjacent to each other, making it possible to control multiple movers with high precision without connecting switches to multiple coils.

[0071] In the second embodiment, the operation and effects when using the control device 1' and drive device 2A shown in FIG. 5 have been described, but the effects obtained in the second embodiment can also be obtained when using the control device 1'' and drive device 2A shown in FIG. 6. Also, the effects obtained in the second embodiment can also be obtained when using the control device 1''' and drive device 2A''' shown in FIG. 7.

[0072] Third Embodiment In a third embodiment, a method for generating a corrected thrust coefficient distribution K'''A(x) that is used when the transport system 10 according to the third embodiment calculates the current command Iref''' will be described.

[0073] First, the corrected thrust coefficient distribution K'A(x) described in the first embodiment can be created with a high degree of freedom, as it can be any waveform obtained by extracting a portion of the actual thrust coefficient distribution K(x). However, creating an inappropriate corrected thrust coefficient distribution K'A(x) poses the problem of not being able to control the mover 4 with high precision. In the third embodiment, a method for generating a corrected thrust coefficient distribution K'''A(x) that can address this problem is proposed.

[0074] FIG. 10 is a diagram illustrating a problem in the third embodiment. In FIG. 10, the actual thrust coefficient distribution KA(x) shown in FIG. 3 is indicated by a dashed line, and the corrected thrust coefficient distribution K″A(x) generated using this actual thrust coefficient distribution KA(x) is indicated by a solid line. The corrected thrust coefficient distribution K″A(x) shown in FIG. 10 is an example of an inappropriate corrected thrust coefficient distribution. Note that in FIG. 10, the horizontal axis of the graph showing the waveform of the current command Iref″ indicates the position of the mover and coincides with the current command “0 (zero).” The same applies to the following figures.

[0075] Although the corrected thrust coefficient distribution K"A(x) shown in FIG. 10 is created using the actual thrust coefficient distribution KA(x), the thrust coefficient values ​​change discontinuously and abruptly. Therefore, the current command Iref" generated using this corrected thrust coefficient distribution K"A(x) also changes discontinuously and abruptly. On the other hand, even if such a current command Iref' is applied to the coil 9, it is difficult to abruptly change the current IA flowing through the coil 9 due to the inductance of the coil 9. This increases the error between the current IA flowing through the coil 9 and the current command Iref", making it difficult to control the multiple movers 4 with high precision.

[0076] 11 is a diagram illustrating a corrected thrust coefficient distribution used in the current command generating unit 13′ according to the third embodiment. The explanation here is based on the control device 1′ and the drive device 2A shown in FIG. 5 or FIG. 10.

[0077] 11, the actual thrust coefficient distribution KA(x) shown in FIG. 3 is shown by a dashed line, and the corrected thrust coefficient distribution K'''A(x) generated using this actual thrust coefficient distribution KA(x) is shown by a solid line. The corrected thrust coefficient distribution K'''A(x) shown in FIG. 11 is an example of an appropriate corrected thrust coefficient distribution.

[0078] FIG. 11 shows an example in which a portion of the actual thrust coefficient distribution KA(x) is used to create a distribution in which the thrust coefficient values ​​are continuous. "Continuous" here means that the thrust coefficient values ​​in the newly created corrected thrust coefficient distribution K'''A(x) do not deviate from the values ​​of the actual thrust characteristic defined by the actual thrust coefficient distribution KA(x). In the example of FIG. 11 , where the thrust coefficient values ​​differ between the actual thrust coefficient distribution KA(x) and the corrected thrust coefficient distribution K'''A(x), the thrust coefficient values ​​in the corrected thrust coefficient distribution K'''A(x) are set to 0. Furthermore, the thrust coefficient values ​​in the corrected thrust coefficient distribution K'''A(x) are set to 0 starting from the zero-crossing points of the actual thrust coefficient distribution KA(x). Therefore, the current command Iref''' generated using this corrected thrust coefficient distribution K'''A(x) changes continuously and smoothly, unlike the case of FIG. 10 . As a result, even if the current flowing through the coil 9 is controlled using the current command Iref''' generated using the corrected thrust coefficient distribution K''A(x), the error between the current IA flowing through the coil 9 and the current command Iref''' can be reduced, making it possible to control multiple movers 4 with high precision.

[0079] As described above, in the conveying system and control device according to the third embodiment, the current command generator generates a current command using a thrust coefficient whose value does not deviate from the value of the actual thrust characteristic determined by the characteristics of the multiple coils and movers. This reduces the error between the current flowing through the coils and the current command, making it possible to control the multiple movers with high precision.

[0080] In the third embodiment, the operation and effects when using the control device 1' and drive device 2A shown in FIG. 5 or FIG. 10 have been described, but the operation may also be performed using the control device 1'' and drive device 2A shown in FIG. 6, or the operation may also be performed using the control device 1''' and drive device 2A''' shown in FIG. 7. In this way, it is possible to enjoy the effects obtained in the first and second embodiments and the effects obtained in the third embodiment.

[0081] Embodiment 4 In the first embodiment, a method for generating a current command Iref' using a corrected thrust coefficient distribution K'A(x) created using a portion of the actual thrust characteristics determined by the characteristics of a plurality of coils and a mover, and further using the above equation (2) has been described. In the fourth embodiment, a method for generating a current command Iref'''' using a calculation equation different from that in the first embodiment will be described.

[0082] FIG. 12 is a diagram illustrating the operation of the control device 1"" according to the fourth embodiment. In FIG. 12, the current command generation unit 13' shown in FIG. 5 is replaced with a current command generation unit 13"". FIG. 12 also shows the same actual thrust coefficient distribution KA(x) as in FIG. 3. FIG. 12 also shows a virtual conductance distribution CA(x). The horizontal axis of the graph showing the waveform of the virtual conductance CA(x) indicates the position of the mover and coincides with the virtual conductance "0 (zero)". FIG. 12 also shows the waveform of a current command calculated from the product of the actual thrust coefficient distribution KA(x) and the virtual conductance distribution CA(x). This current command waveform is a waveform that represents the relationship between the mover position, which indicates the distance from the center position of the mover 4, and the current command. The virtual conductance distribution CA(x) is a waveform that represents the relationship between the mover position, which indicates the distance from the center position of the mover 4, and the virtual conductance. The virtual conductance is a correction coefficient that changes depending on the position of the mover. In Fig. 12, the same or equivalent parts as those in Fig. 5 are denoted by the same reference numerals, and duplicated explanations will be omitted where appropriate.

[0083] Next, a method for generating the current command Iref'''' in the fourth embodiment will be described. Note that, although a generation method using the actual thrust coefficient distribution KA(x) shown in FIG. 3 will be described below, the corrected thrust coefficient distribution K'A(x) shown in FIGS. 4 and 5 or the corrected thrust coefficient distribution K'''A(x) shown in FIG. 11 may also be used.

[0084] The current command generation unit 13'''' generates current target values, which are target values ​​of drive currents to be applied to the multiple coils 9, as current commands Iref'''', based on the thrust command τref and the motion detection value y that indicates the motion position or motion speed of the mover 4. Specifically, the current command generation unit 13'''' calculates current commands Iref''''A1 to Iref''''A5, which are target values ​​of drive currents to be applied to the coils 9A1 to 9A5, using the following equation (5). Note that the current command generation unit 13'''' calculates a current command Iref'''' for each of the coils 9 of each coil unit 3 included in the transportation system 10, but here, for convenience, the calculation of five current commands Iref''''A1 to Iref''''A5 will be described.

[0085] Iref''''A1=KA1・CA1 / (KA1^2・CA1+KA2^2・CA2+KA3^2・CA3+KA4^2・CA4+KA5^2・CA5)×τref Iref''''A2=KA2・CA2 / (KA1^2・CA1+KA2^2・CA2+KA3^2・CA3+KA4^2・CA4+KA5^2・CA5)×τref Iref''''A3=KA3・CA3 / (KA1^2・CA1+KA2^2・CA2+KA3^2・CA3+KA4^2・CA4+KA5^2・CA5)×τref Iref''''A4=KA4・CA4 / (KA1^2・CA1+KA2^2・CA2+KA3^2・CA3+KA4^2・CA4+KA5^2・CA5)×τref Iref''''A5=KA5・CA5 / (KA1^2・CA1+KA2^2・CA2+KA3^2・CA3+KA4^2・CA4+KA5^2・CA5)×τref...Formula (5)

[0086] In equation (5), CA1 to CA5 are virtual conductances, which are coefficients introduced to adjust the value of the current command Iref''''A calculated by the current command generation unit 13''''. The virtual conductances CA1 to CA5 can be obtained from the virtual conductance distribution CA(x).

[0087] It is also known that the relationship between the current flowing through the coils 9A1 to 9A5 and the thrust τ generated in the mover 4 can be expressed by the following equation (6).

[0088] τ=KA1・IA1+KA2・IA2+KA3・IA3+KA4・IA4+KA5・IA5...Formula (6)

[0089] Although detailed transformation of the equations will be omitted, by substituting τ in equation (6) for τref in equation (5), the current commands Iref''''A1 to Iref''''A5 calculated by equation (5) can set the thrust τ generated in the mover 4 to the thrust command τref, which is the target value of the thrust τ, regardless of the values ​​of the virtual conductances CA1 to CA5. In other words, even if the virtual conductances CA1 to CA5 are introduced, the thrust τ generated in the mover 4 will not deviate from the thrust command τref.

[0090] According to the calculation formula (5), when the product of the thrust coefficients KA1 to KA5 and the virtual conductances CA1 to CA5 is 0, a current command Iref''''A of 0 [A] is generated. The current command Iref''''A of 0 [A] is input to the current control unit 22A via the data communication units 14, 21A. The current control unit 22A controls the current flowing through the coil 9A to 0 [A]. As a result, no drive current flows through the coil 9A to which the current command Iref''''A of 0 [A] is commanded.

[0091] On the other hand, when the product of the thrust coefficients KA1 to KA5 and the virtual conductances CA1 to CA5 is not 0, a current command Iref''''A that is not 0 [A] is generated. The current command Iref''''A that is not 0 [A] is input to the current control unit 22A via the data communication units 14, 21A. The current control unit 22A controls the current flowing through the coil 9A to a value that is not 0 [A]. As a result, a drive current flows through the coil 9A to which the current command Iref''''A that is not 0 [A] is commanded.

[0092] As can be understood from the above explanation, when the calculation formula (5) is used, the number of coils through which the drive current flows can be freely changed by adjusting the values ​​of the virtual conductances CA1 to CA5 by which the thrust coefficients KA1 to KA5 are multiplied, and it becomes possible to reduce the number of coils through which the drive current flows without connecting switches to the multiple coils 9. In other words, generating the current command Iref''''A so as to reduce the number of coils through which the drive current flows by using the virtual conductances CA1 to CA5 by which the thrust coefficients KA1 to KA5 are multiplied means generating the current target value to be applied to the multiple coils 9 using part of the actual thrust force characteristics determined by the characteristics of the multiple coils 9 and the mover 4.

[0093] Furthermore, by using a virtual conductance distribution CA(x) such that the change characteristics of the values ​​obtained by multiplying each of the thrust coefficients KA1 to KA5 by the virtual conductances CA1 to CA5 do not deviate from the values ​​of the actual thrust characteristics defined by the actual thrust coefficient distribution KA(x), a continuously and smoothly changing current command Iref''' can be generated.

[0094] As described above, in the conveying system and control device according to the fourth embodiment, the current command generator generates current target values ​​to be applied to the multiple coils using corrected thrust characteristics created using actual thrust characteristics determined by the characteristics of the multiple coils and movers and a correction coefficient that changes depending on the position of the mover. In other words, in the conveying system and control device according to the fourth embodiment, the current command generator generates current target values ​​to be applied to the multiple coils using part of the actual thrust characteristics determined by the characteristics of the multiple coils and movers. This reduces the error between the currents flowing through the coils and the current commands, making it possible to control the multiple movers with high precision.

[0095] In the fourth embodiment, the operation and effects of using the control device 1 and drive device 2A shown in FIG. 3 have been described, but the operation may also be performed using the control device 1' and drive device 2A shown in FIGS. 5 and 9, or the control device 1" and drive device 2A shown in FIG. 6, or the control device 1"' and drive device 2A"' shown in FIG. 7. Furthermore, the control device 1' and drive device 2A shown in FIG. 5 may be operated using the corrected thrust coefficient distribution K'"A(x) described in the third embodiment. In this way, it is possible to enjoy the effects obtained in the first to third embodiments and the effects obtained in the fourth embodiment.

[0096] Finally, the hardware configuration for realizing the functions of the control devices 1 to 1"" and drive devices 2A to 2H described above will be described with reference to FIGS. 13 and 14. FIG. 13 is a block diagram showing an example of a hardware configuration for realizing the functions of the control devices 1 to 1"" and drive devices 2A to 2H in the first to fourth embodiments. FIG. 14 is a block diagram showing another example of a hardware configuration for realizing the functions of the control devices 1 to 1"" and drive devices 2A to 2H in the first to fourth embodiments.

[0097] When realizing some or all of the functions of the control devices 1 to 1'''' and drive devices 2A to 2H in embodiments 1 to 4, the configuration can include a processor 300 that performs calculations, a memory 302 in which programs read by the processor 300 are stored, and a communication circuit 304 that transmits and receives signals, as shown in Figure 13.

[0098] The processor 300 is an example of a computing unit. The processor 300 may be a computing unit called a microprocessor, a microcomputer, a central processing unit (CPU), or a digital signal processor (DSP). Examples of the memory 302 include non-volatile or volatile semiconductor memory such as random access memory (RAM), read-only memory (ROM), flash memory, erasable programmable read-only memory (EPROM), and electrically programmable read-only memory (EEPROM), as well as a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, and a digital versatile disk (DVD).

[0099] The memory 302 stores programs that execute the functions of the control devices 1 to 1'''' and drive devices 2A to 2H in the first to fourth embodiments. The processor 300 exchanges necessary information via the communication circuit 304, executes the programs stored in the memory 302, and refers to the tables stored in the memory 302, thereby performing the above-mentioned processing. The results of calculations by the processor 300 can be stored in the memory 302.

[0100] Furthermore, when realizing some of the functions of the control devices 1 to 1'''' and drive devices 2A to 2H in the first to fourth embodiments, a processing circuit 303 shown in FIG. 14 can be used. The processing circuit 303 may be a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Information input to and output from the processing circuit 303 can be exchanged via a communication circuit 304.

[0101] Note that some of the processing in the control devices 1 to 1 ″″ and drive devices 2 A to 2 H may be performed by the processing circuit 303 , and the processing that is not performed by the processing circuit 303 may be performed by the processor 300 and memory 302 .

[0102] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention.

[0103] 1, 1', 1'', 1''', 1'''' Control device, 2, 2A to 2H Drive device, 3, 3A to 3H Coil unit, 4, 4A to 4C Mover, 5, 5A to 5C Scale head, 6, 6A, 6B Linear scale, 7 Data communication line, 7A, 7B Communication line, 8 Transfer path, 9, 9A1 to 9A5, 9B1, 9B2 Coil, 10 Transfer system, 11 Operation target value generation unit, 12, 25A''' Position and speed control unit, 13, 13', 13'', 13'''', 26A''' Current command generation unit, 14, 21A, 21B Data communication unit, 15, 15'', 15''' Thrust command generation unit, 17A, 17B Arrow, 20A, 20B Drive unit, 22A, 22A1 to 22A5 Current control unit, 23A, 23A1 to 23A5 current detectors, 24A, 24B detector communication unit, 40 permanent magnet, 300 processor, 302 memory, 303 processing circuit, 304 communication circuit.

Claims

1. A transportation system having a mover and a transport path along which the mover moves, comprising: a drive unit that supplies drive current to multiple coils arranged along the transport path; a thrust command generation unit that generates a thrust command, which is a command value for thrust to be generated by the mover, based on an operation target value that is a target value for a time-series operation that is input from outside or generated internally; and a current command generation unit that generates, as a current command, a current target value, which is a target value for drive current to be provided to the multiple coils so that the thrust generated by the mover follows the thrust command, wherein the current command generation unit generates the current target value to be provided to the multiple coils by using a portion of actual thrust characteristics determined by the characteristics of the multiple coils and the mover so as to reduce the number of coils through which the drive current flows.

2. The transport system according to claim 1, characterized in that the thrust command generating unit generates the thrust command so that a motion detection value representing the motion position or motion speed of the mover tracks the motion target value.

3. The conveying system according to claim 2, characterized in that the conveying system is configured to include a drive device and a control device, the drive device including the drive section, the control device including the current command generating section and the thrust command generating section, and the thrust command generating section including: a motion target value generating section that generates the motion target value, and a position and speed control section that generates the thrust command so that the motion detection value follows the motion target value.

4. The conveying system according to claim 2, characterized in that the conveying system is configured to include a drive unit and a control unit, the thrust command generating unit includes a motion target value generating unit that generates the motion target value, and a position and speed control unit that generates the thrust command so that the motion detection value follows the motion target value, the drive unit includes the drive unit, the position and speed control unit, and the current command generating unit, and the control unit includes the motion target value generating unit.

5. A conveying system as described in any one of claims 1 to 4, characterized in that when a plurality of the movers are provided, and a plurality of coils for driving a first mover, which is any one of the plurality of movers, are defined as a first coil group, and a plurality of coils for driving a second mover adjacent to the first mover are defined as a second coil group, the current command generating unit generates a current target value to be given to the coils of the first coil group using a portion of the actual thrust force characteristics determined by the characteristics of the coils of the first coil group and the first mover, and generates a current target value to be given to the coils of the second coil group using a portion of the actual thrust force characteristics determined by the characteristics of the coils of the second coil group and the second mover.

6. The transport system according to claim 5, wherein the current command generating unit generates a current target value using a thrust coefficient whose value does not deviate from the value of the actual thrust characteristic.

7. A conveying system as claimed in any one of claims 1 to 6, characterized in that the current command generating unit generates current target values ​​to be given to the multiple coils using corrected thrust characteristics created using actual thrust characteristics determined by the characteristics of the multiple coils and the mover, and a correction coefficient that changes depending on the position of the mover.

8. A control device configured to be applicable to a conveyance system including a mover, a conveyance path along which the mover moves, and a drive device that supplies drive current to a plurality of coils arranged along the conveyance path, the control device comprising: a thrust command generation unit that generates a thrust command, which is a command value for thrust to be generated in the mover, based on an operation target value that is a target value for time-series operation input from outside or generated internally; and a current command generation unit that generates, as a current command, a current target value that is a target value for drive current to be supplied to the plurality of coils so that the thrust generated by the mover follows the thrust command, wherein the current command generation unit generates the current target value to be supplied to the plurality of coils by using a portion of actual thrust characteristics determined by the characteristics of the plurality of coils and the mover so as to reduce the number of coils through which the drive current flows.

9. The control device described in claim 8, characterized in that when a plurality of the movers are provided, and a plurality of coils that drive a first mover, which is any one of the plurality of movers, are defined as a first coil group, and a plurality of coils that drive a second mover adjacent to the first mover are defined as a second coil group, the current command generation unit generates a current target value to be given to the coils of the first coil group using a portion of the actual thrust force characteristics determined by the characteristics of the coils of the first coil group and the first mover, and generates a current target value to be given to the coils of the second coil group using a portion of the actual thrust force characteristics determined by the characteristics of the coils of the second coil group and the second mover.

10. The control device according to claim 9, characterized in that the current command generating unit generates a current target value using a thrust coefficient whose value does not deviate from the value of the actual thrust characteristic.

11. A control device as described in any one of claims 8 to 10, characterized in that the current command generation unit generates current target values ​​to be given to the multiple coils using corrected thrust characteristics created using actual thrust characteristics determined by the characteristics of the multiple coils and the mover, and a correction coefficient that changes depending on the position of the mover.

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