Funding system

Abstract

Conveyor system (1), comprising: a plurality of conveying path units (11A to 11H) forming a conveying path (10) along which a conveyed body moves, each of the conveying path units (11A to 11H) comprising a plurality of drive units (21a to 21i) each generating a thrust for moving the conveyed body by means of a current flowing through them; and a controller (12) with a current command generator (42) generating a current command for controlling a current flowing through the plurality of drive units (21a to 21i), each of the plurality of conveying path units (11A to 11H) comprising a communication substation (29) connected to the controller (12) via a data communication line (15), and a plurality of current controllers (25) each controlling the current flowing through each of the plurality of drive units (21a to 21i) in accordance with the current command.wherein the current command generator (42) generates a current command to perform current control (25) of all of the plurality of drive units (21a to 21i) of each of the conveying path units (11A to 11H) at each control cycle when the current command is generated, wherein the plurality of conveying path units (11A to 11H) move each of the plurality of conveying bodies by applying the thrust to each of the plurality of conveying bodies, wherein the current command generator (42) receives a current command for each of the conveying bodies for each of the drive units (21a to 21i) and adds current commands for the conveying bodies for each of the drive units (21a to 21i) to generate a current command for each of the drive units (21a to 21i), and wherein the communication substation (29) receives from the controller (12) the generated current command for each of the drive units (21a to 21i), and the generated current command to each of the majority of power controllers (25).

Description

Technical area

[0001] The present disclosure relates to a conveyor system that conveys an object. background

[0002] A conveyor system that conveys a workpiece is generally used in a production line where factory automation is implemented, such as a production line for assembling industrial products or a production line for packaging food. In recent years, many conveyor systems have been used in which a conveyor path for conveying workpieces is divided into a plurality of zones, and a carrier on which a workpiece is placed is controlled to move by a control device arranged in each zone. Such a conveyor system is known as one of the conveyor systems due to its excellent production efficiency.

[0003] Patent Literature 1 discloses a conveying system using a linear motor. The conveying system disclosed in Patent Literature 1 includes a carrier having a magnet and a plurality of coil units arranged on a conveying path. Each coil unit includes a plurality of coils. The conveying system disclosed in Patent Literature 1 generates thrust to move the carrier through an interaction between a current flowing through the coils and a magnetic field generated by the magnet. According to Patent Literature 1, switches are connected to the respective coil units, and the power supply to the coils and the interruption of current flow to the coils are switched by opening and closing the switches. The conveying system disclosed in Patent Literature 1 detects a position of the carrier on the conveying path and selects a coil unit at a position where thrust can be applied to the carrier.The conveyor system disclosed in Patent Literature 1 supplies power to the selected coil unit by closing the switches and interrupts power to coil units other than the selected coil unit by opening the switches. Citation listPatent literature

[0004] Patent Literature 1: Japanese Patent Application Laid-Open No. 2017-79569 Overview of the inventionThe problem to be solved by the invention

[0005] In the conveyor system disclosed in Patent Literature 1, the switches are provided separately from a current controller that controls the current flowing to the coils. In the conveyor system disclosed in Patent Literature 1, the switches are required, and therefore a circuit configuration becomes correspondingly complicated. Further, in the conveyor system disclosed in Patent Literature 1, it is necessary to generate and output an opening / closing command for controlling the switches separately from a current command to be input to the current controller. According to the technique of Patent Literature 1, methods for controlling the conveyor system become complicated in order to generate and output the opening / closing command separately from the current command. As described above, in the conveyor system disclosed in Patent Literature 1, the circuit configuration becomes complicated and the methods for controlling the conveyor system become complicated, which is problematic.

[0006] The present disclosure has been made in view of the above, and an object thereof is to obtain a conveyor system in which a circuit configuration can be simplified and control can be performed by simple methods. Means of solving the problem

[0007] To solve the problems described above and achieve the object, a conveyor system according to the present disclosure includes: a plurality of conveyor path units constituting a conveyor path on which a conveyor body moves, each of the conveyor path units including a plurality of drive units each generating a thrust for moving the conveyor body by a current flowing therethrough; and a controller including a current command generator that generates a current command for controlling a current flowing through the plurality of drive units. Each of the plurality of conveyor path units controls the current flowing through each of the plurality of drive units in accordance with the current command. The current command generator generates a current command for performing current control of all of the plurality of drive units of each of the conveyor path units at each control cycle when the current command is generated. Effects of the invention

[0008] The conveyor system according to the present disclosure achieves the effect that a circuit configuration can be simplified and control can be performed by simple methods. Short description of the drawings Fig. 1 is a diagram showing an exemplary configuration of a conveyor system according to a first embodiment. Fig. 2 is a diagram showing an exemplary configuration of a conveyance path unit included in the conveyance system according to the first embodiment. Fig. 3 is a diagram showing an exemplary configuration of a track controller included in the conveyor system according to the first embodiment. Fig. 4 is a flowchart showing a processing procedure by a current command generator of the conveyor system according to the first embodiment. Fig. 5 is a diagram showing an example of a relationship between a position of a carrier and a thrust constant of a coil in the first embodiment. Fig. 6 is a diagram showing examples of calculation results of current commands by the conveyor system according to the first embodiment. Fig. 7 is a diagram showing an exemplary configuration of the conveyance path unit included in the conveyance system according to a second embodiment. Fig. 8 is a diagram showing an example of a thrust command used to generate a current command for each coil in the conveyor system according to the second embodiment. Fig. 9 is a diagram showing an exemplary configuration of a track controller included in the conveyor system according to a third embodiment. Fig. 10 is a diagram showing an exemplary configuration of a learning device included in the conveyance system according to the third embodiment. Fig. 11 is a flowchart showing a processing method of the learning device included in the conveyor system according to the third embodiment. Fig. 12 is a diagram showing an exemplary configuration of a carrier position controller included in the conveyor system according to the third embodiment. Fig. 13 is a flowchart showing a processing method of the carrier position control included in the conveyor system according to the third embodiment. Fig. 14 is a diagram showing an exemplary configuration of a control circuit according to the first to third embodiments. Fig. 15 is a diagram showing an exemplary configuration of a hardware circuit as a dedicated circuit according to the first to third embodiments. Description of the embodiments

[0009] Hereinafter, a conveyor system according to each embodiment will be described in detail with reference to the drawings. First embodiment.

[0010] Fig. 1 is a diagram showing an exemplary configuration of a conveyor system 1 according to a first embodiment. The conveyor system 1 is a system used to convey an object. In the first embodiment, the conveyor system 1 conveys an object by moving a conveyor body on which the object is placed.

[0011] The conveyor system 1 includes a plurality of conveyor path units 11A to 11H, a controller 12, a direct current power supply 13 (DC supply), and carriers 17A, 17B, and 17C. The controller 12 controls the plurality of conveyor path units 11A to 11H. The controller 12 includes a motion controller 19 and a tracking controller 20. In the following description, the conveyor path units 11A to 11H are each referred to as conveyor path unit 11 unless they are distinguished from each other.

[0012] The plurality of conveying path units 11 are coupled to each other and form a conveying path 10 along which the conveying body moves. The plurality of conveying path units 11 move the conveying body by applying driving force to the conveying body. Each of the carriers 17A, 17B, and 17C is a conveying body. In the following description, the carriers 17A, 17B, and 17C are each referred to as carrier 17 unless otherwise distinguished from one another.

[0013] The Fig. The conveying path 10 shown in Figure 1 has a ring-shaped configuration. This means that the Fig. The conveyor path 10 shown in Figure 1 is a closed path. The conveyor path 10 of the conveyor system 1 may be an open path. That is, the conveyor path 10 of the conveyor system 1 may be a path with a starting point and an end point.

[0014] The conveying path units 11A, 11B, 11E, and 11F each constitute a linear conveying path unit 11 that forms a linear path. The conveying path units 11C, 11D, 11G, and 11H each constitute a curved conveying path unit 11 that forms a curved path and changes the movement direction of the conveying body. The conveying path 10 may include only the conveying path units 11 that each form a curved path, without including the conveying path units 11 that each form a linear path. Any shape can be used as the overall shape of the conveying path 10.

[0015] The carrier 17 is attached to a side surface of the conveying path 10. The carrier 17 moves along a guide rail provided on the side surface of the conveying path 10. The carrier 17 moves along the side surface of the conveying path 10 and stops on the side surface of the conveying path 10. The conveying system 1 according to the first embodiment is a linear motor with a movable magnet. The carrier 17 can move along a guide rail provided on an upper surface of the conveying path 10. The carrier 17 includes a permanent magnet that forms a moving device, a permanent magnet for a linear scale, and a guide roller that moves by rotation on the guide rail. Fig. 1, the guide rail, the guide roller, the permanent magnet constituting a moving device, and the permanent magnet for a linear scale are not shown.

[0016] The direction of movement of each carrier 17 is in Fig. 1 a clockwise direction or a counterclockwise direction. Among the directions of movement, the clockwise direction is Fig. 1 is defined as the forward direction. Among the directions of movement, the counterclockwise direction is Fig. 1 is defined as the reverse direction. An arrow 18A indicates the forward direction. An arrow 18B indicates the reverse direction.

[0017] In the Fig. In the example shown in Figure 1, the conveyor system 1 comprises eight conveyor path units 11 and three carriers 17. The conveyor system 1 may comprise any number of conveyor path units 11. That is, there may be any number of conveyor path units 11 forming the conveyor path 10. The conveyor system 1 need only comprise a plurality of conveyor path units 11. There may be any number of carriers 17 moving along the conveyor path 10. The conveyor system 1 need only comprise one or a plurality of carriers 17.

[0018] The conveyor system 1 is not limited to a system with a linear motor and can be a system with a rotary motor. The conveyor system 1 can be a belt conveyor with a rotary motor and a belt rotated by the rotary motor. The belt conveyor moves a workpiece placed on the belt. The conveyor system 1 can be a roller conveyor with a plurality of rollers and a rotary motor that rotates the rollers. The roller conveyor moves a workpiece placed on the rollers.

[0019] The DC power supply 13 is connected to each conveyor path unit 11 via a DC power supply bus 16. The DC power supply 13 is a power supply device or circuit that outputs a DC voltage. The DC power supply 13 supplies electrical power to each conveyor path unit 11. Each conveyor path unit 11 shares the DC power supply 13.

[0020] A positive-side DC bus and a negative-side DC bus pass through the DC power supply bus 16. The positive-side DC bus is referred to as a P bus. The negative-side DC bus is referred to as an N bus. The P bus is connected to a positive electrode of the DC power supply 13. The N bus is connected to a negative electrode of the DC power supply 13. Hereinafter, when both the P bus and the N bus are referred to, the buses are referred to as PN buses. Each of the plurality of conveyance path units 11 constituting the conveyance path 10 is connected to common PN buses.

[0021] The conveyor system 1 has a configuration in which each conveyor path unit 11 is connected to the DC power supply 13 via a multi-point connection. The connection form between each conveyor path unit 11 and the DC power supply 13 is not limited to the multi-point connection and may be a daisy-chain connection. In the Fig. In the example shown in Figure 1, the conveyor system 1 includes one DC power supply 13, but the conveyor system 1 may include two or more DC power supplies 13. That is, a plurality of power supply areas may be configured in the conveyor system 1.

[0022] The track controller 20 is connected to each conveying path unit 11 via a data communication line 15. The data communication line 15 includes a line connecting the track controller 20 and the conveying path unit 11A, which is one of the plurality of conveying path units 11, and lines connecting the adjacent conveying path units 11. The conveying system 1 has a configuration in which each conveying path unit 11 is connected to the track controller 20 through a daisy-chain connection. A connection form between each conveying path unit 11 and the track controller 20 is not limited to the daisy-chain connection. The connection form between each conveying path unit 11 and the track controller 20 may be a star connection in which each conveying path unit 11 is connected to the track controller 20 via a communication node.Alternatively, the conveyor system 1 may include a plurality of data communication lines 15, and each conveyor path unit 11 and the track controller 20 may be directly connected through the data communication line 15.

[0023] The motion controller 19 is connected to the tracking controller 20 via a data communication line 14. The motion controller 19 periodically generates a position command indicating a position to which each carrier 17 is moved. The motion controller 19 transmits the generated position command to the tracking controller 20. Details of the tracking controller 20 will be described later.

[0024] The Fig. The conveyor system 1 shown in Figure 1 includes a motion controller 19 and a track controller 20. The conveyor system 1 may include two or more track controllers 20, and each track controller 20 may be connected to the motion controller 19. One, two, or more conveyor path units 11 are connected to each track controller 20. A communication protocol between the motion controller 19 and the track controller 20 and a communication protocol between the track controller 20 and each conveyor path unit 11 may be the same or different.

[0025] A higher-level control device, such as a programmable logic controller, that is higher than the controller 12 may be connected to the motion controller 19. The control device outputs a command for sequential control to the motion controller 19. A human-machine interface may be connected to the motion controller 19. The human-machine interface receives input from an operator. Furthermore, the human-machine interface outputs information about the state of the conveyor system 1 through a display or the like. The motion controller 19 may obtain operation information of the carriers 17 from the higher-level control device or the human-machine interface and generate the position command based on the operation information. The operation information is information indicating a schedule for the movement of each of the plurality of carriers 17 on the conveyor path 10.

[0026] Next, a configuration of the conveyor path unit 11 will be described. Here, the configuration of the conveyor path unit 11 will be described using the linear conveyor path unit 11 as an example. The curved conveyor path unit 11 differs from the linear conveyor path unit 11 in the arrangement of the coils. The configuration of the curved conveyor path unit 11 is similar to the configuration of the linear conveyor path unit 11, except for the different arrangement of the coils.

[0027] Fig. 2 is a diagram showing an exemplary configuration of the conveyance path unit 11 included in the conveyance system 1 according to the first embodiment. Fig. Figure 2 shows the conveyor path unit 11 and the permanent magnets 30 and 31 enclosed in the carrier 17. The permanent magnet 30 is a permanent magnet that forms a moving device. The permanent magnet 31 is a permanent magnet for a linear scale.

[0028] The conveying path unit 11 includes a plurality of coils 21a to 21i. In the following description, the coils 21a to 21i are each referred to as coil 21 unless otherwise distinguished. Each coil 21 functions as a drive unit that generates thrust through a current flowing therethrough. Each coil 21 generates an electromagnetic force that generates thrust through an interaction between a current and a magnetic field generated by the permanent magnet 30.

[0029] In the Fig. In the example shown in Figure 2, the conveying path unit 11 includes nine coils 21. Any number of coils 21 may be included in the conveying path unit 11. In the linear conveying path unit 11, the plurality of coils 21 are arranged in a linear direction. In the curved conveying path unit 11, the plurality of coils 21 are arranged in a curved direction.

[0030] An inverter circuit 22 is connected to each of the coils 21 of the conveyor path unit 11. The inverter circuit 22 includes switching elements and supplies the coil 21 with electrical energy, which undergoes power conversion by switching the switching elements. The switching elements are not shown. The inverter circuit 22 controls a current flowing through the coil 21. The inverter circuit 22 is a single-phase full-bridge inverter circuit or a single-phase half-bridge inverter circuit. The inverter circuit 22 may be a three-phase inverter circuit connected to three coils 21. Each of the coils 21 of the conveyor path unit 11 includes not only a pure inductance component but also a coil resistance.

[0031] Each inverter circuit 22 of the conveyor path unit 11 is connected between the P bus and the N bus. Each inverter circuit 22 converts DC power from the PN buses into AC power and supplies the AC power to the coil 21. The inverter circuit 22 performs power conversion from DC power to AC power by switching the switching elements.

[0032] With the power supply converted by the inverter circuit 22, the coil 21 generates an electromagnetic force that provides thrust to move the carrier 17. A current sensor 23 is connected to each coil 21 of the conveying path unit 11. The current sensor 23 detects an actual coil current value, which is a current value of a current flowing through the coil 21. In the conveying path unit 11, a capacitor 24, which is an electrolytic capacitor, is connected between the P bus and the N bus.

[0033] A current controller 25 is connected to each of the inverter circuits 22 of the conveying path unit 11, which controls the inverter circuit 22. The current controller 25 calculates a voltage value of a voltage to be applied to the coil 21 based on a current command value of the current flowing through the coil 21 and the actual coil current value detected by the current sensor 23. The current controller 25 transmits to the inverter circuit 22 a pulse width modulation (PWM) signal obtained by comparing the calculated voltage value with a triangular waveform. The current controller 25 transmits the PWM signal to the inverter circuit 22, thereby causing the inverter circuit 22 to switch. As a result, the current controller 25 applies a voltage to the coil 21 to cause a current of a desired current value to flow through the coil 21.The current controller 25 may calculate the voltage value of the voltage to be applied to the coil 21 by performing proportional-integral-derivative (PID) control of the voltage to be applied to the coil 21 based on a deviation between the current command value and the actual coil current value.

[0034] An arrangement interval of the plurality of coils 21 in the moving direction of the carrier 17 is denoted by L coil It should be noted that L coil is a distance between the center positions of the coils 21 that are adjacent to each other in the conveying path unit 11. L carrier is the length of the beam 17 in the direction of movement of the beam 17. L coil is shorter than L carrier . As a result, each carrier 17 can receive a thrust by an interaction between magnetic fluxes generated by two or more coils 21.

[0035] The length of the permanent magnet 30 in the direction of movement of the carrier 17 is L magnet L magnet is a length from one end of the permanent magnet 30 to the other end of the permanent magnet 30 in the moving direction of the carrier 17. In a case where N-poles and S-poles are alternately arranged as in Fig. 2, L magnet the length of the entire permanent magnet 30 including all magnetic poles in the direction of movement of the carrier 17. In a case where there is a gap between a magnetic pole and a magnetic pole, L magnet also the length of the gap.

[0036] L magnet is shorter than L carrier . Since L magnet shorter than L carrierIn a case where two carriers 17 approach each other, a gap is provided between the permanent magnet 30 of one carrier 17 and the permanent magnet 30 of the other carrier 17. Since the gap is provided between the permanent magnet 30 of one carrier 17 and the permanent magnet 30 of the other carrier 17, a state in which the permanent magnet 30 of one carrier 17 and the permanent magnet 30 of the other carrier 17 are located on one coil 21 can be avoided. Since the permanent magnet 30 present on one coil 21 is the permanent magnet 30 of one carrier 17, a calculation of a current command for generating a magnetic flux in one coil 21 can be set as a calculation for one carrier 17.On the other hand, if it is necessary to set the calculation of the current command for generating the magnetic flux in one coil 21 as a calculation for two carriers 17, the calculation of the current command for generating the magnetic flux in one coil 21 becomes complicated as a calculation for two carriers 17.

[0037] According to the first embodiment, the conveyor system 1, since L magnet shorter than L carrier is to set the calculation of the current command for generating the magnetic flux in a coil 21 as a calculation for a carrier 17. Therefore, the conveyor system 1 can prevent the calculation of the current command from becoming complicated.

[0038] The conveying path unit 11 includes a linear scale 26, a processor 28, and a communication substation 29. The linear scale 26 is a sensor unit that detects the position of the carrier 17 on the conveying path unit 11. The linear scale 26 is provided on the conveying path 10 through the plurality of conveying path units 11, which are coupled together to form the conveying path 10. The processor 28 is a central processing unit (CPU). The processor 28 can be an arithmetic device, a processing device, a microprocessor, a microcomputer, or a digital signal processor (DSP).

[0039] The linear scale 26 includes a plurality of position sensors 27. Each position sensor 27 is a sensor that detects a magnetic field, such as a Hall sensor or a magnetoresistive sensor. Each position sensor 27 detects a magnetic field of the permanent magnet 30 or a magnetic field of the permanent magnet 31. Here, the position sensor 27 is a Hall sensor on which two Hall elements are mounted. A distance between the two Hall elements is equal to a distance corresponding to half a magnetic pole pitch of the permanent magnet 31. Each Hall element converts a magnetic field into an electrical signal and outputs the electrical signal. The electrical signal output from each Hall element changes with the movement of the carrier 17. The electrical signal output from one Hall element has a sine wave waveform. The electrical signal output from the other Hall element has a cosine wave waveform.

[0040] The electrical signal from each position sensor 27 of the linear scale 26 is input to the processor 28. An analog-to-digital converter (AD converter) included in the processor 28 detects the sine wave and the cosine wave. The processor 28 detects the position of the carrier 17 relative to the position sensor 27 by calculating arctan based on information about the sine wave and information about the cosine wave. As a result, the processor 28 obtains position sensor information indicating the relative position of the carrier 17 relative to the position sensor 27. Fig. 2, a communication line of the electrical signal between each position sensor 27 and the processor 28 is not shown.

[0041] The communication substation 29 is a communication substation located on one side of the conveying path unit 11. The data communication line 15 is connected to the communication substation 29. In a case where each conveying path unit 11 and the track controller 20 are connected by the daisy-chain connection, the communication substation 29 is configured to connect two lines constituting the data communication lines 15. For each of the plurality of coils 21 included in the conveying path unit 11, the communication substation 29 receives from the track controller 20 a current command indicating a command value of a current to flow through the coil 21. The communication substation 29 transmits the current command to each of the plurality of current controllers 25 of the conveying path unit 11. As a result, the conveying path unit 11 controls the current flowing through each of the plurality of coils 21 in accordance with the current command.

[0042] The communication substation 29 obtains the position sensor information from the processor 28. The communication substation 29 transmits the obtained position sensor information to the track controller 20.

[0043] For example, the communication substation 29 performs fixed-cycle communication, in which a current command is received and position sensor information is transmitted in a fixed cycle. Instead of fixed-cycle communication, the communication substation 29 may perform the reception of the current command and the transmission of the position sensor information aperiodically.

[0044] As described above, the conveying path unit 11 mainly has the function of performing excitation control of the coils 21 and has the function of acquiring position sensor information. Each of the plurality of conveying path units 11 constituting the conveying path 10 similarly performs excitation control of the coils 21 and similarly acquires position sensor information.

[0045] Next, a configuration of the track control 20 is described. Fig. 3 is a diagram showing an exemplary configuration of the track controller 20 included in the conveyor system 1 according to the first embodiment. The track controller 20 includes a carrier position controller 41, a current command generator 42, a position information generator 43, a communication substation 44, and a communication master station 45.

[0046] The communication substation 44 is a communication substation on the side of a track controller 20. The communication substation 44 receives a position command from the motion controller 19. In the first embodiment, the communication substation 44 receives position commands for the carriers 17A, 17B, and 17C of the conveying path units 11. The communication substation 44 receives a position command for each carrier 17 of the conveying path units 11 and outputs the received position command to the carrier position controller 41.

[0047] The communication master station 45 is a communication master station located on the track controller 20 side. The communication master station 45 receives the position sensor information from the communication sub-station 29 of each conveying path unit 11. That is, the communication master station 45 receives the position sensor information acquired from the processor 28 of each conveying path unit 11. The communication master station 45 outputs the received position sensor information to the position information generator 43.

[0048] The position information generator 43 acquires the position sensor information from each conveying path unit 11 and calculates the position of each carrier 17 based on the acquired position sensor information. The position information generator 43 generates position information indicating the actual position of each carrier 17 on the conveying path 10. In the first embodiment, the position information generator 43 generates the position information of the carriers 17A, 17B, and 17C, which indicates the actual positions of the carriers 17A, 17B, and 17C on the conveying path 10. The position information generator 43 generates the position information of each carrier 17 of the conveying system 1 and outputs the generated position information to the carrier position controller 41 and the current command generator 42.

[0049] The carrier position controller 41 acquires the position command of each carrier 17 and the position information of each carrier 17. The carrier position controller 41 generates a push command for each carrier 17 based on a difference between the position command and the position information. In the first embodiment, the carrier position controller 41 generates the push command of the carrier 17A based on a difference between the position command of the carrier 17A and the position information of the carrier 17A. The carrier position controller 41 generates a push command of the carrier 17B based on a difference between the position command of the carrier 17B and the position information of the carrier 17B. The carrier position controller 41 generates a push command of the carrier 17C based on a difference between the position command of the carrier 17C and the position information of the carrier 17C.The carrier position controller 41 outputs the generated thrust commands to the current command generator 42.

[0050] The current command generator 42 acquires the thrust command of each carrier 17 and the position information of each carrier 17. The current command generator 42 generates current commands for controlling a current flowing through the plurality of coils 21 based on the thrust commands and the position information. In each control cycle, when a current command is generated in the track controller 20, the current command generator 42 generates current commands for performing current control of all of the plurality of coils 21 of each conveying path unit 11. Here, the "control cycle" refers to a control cycle from the generation of the position information of the carrier 17 by the position information generator 43 to the generation of the current commands for the coils 21 of each conveying path unit 11 by the current command generator 42.That is, the current command generator 42 of the first embodiment generates current commands for all of the plurality of coils 21 of each conveying path unit 11 in each control cycle when a current command is generated. The current command generator 42 outputs the generated current commands to the communication master station 45. The communication master station 45 transmits the current commands to the communication sub-station 29 of each conveying path unit 11. In the following description, a group of current commands, each of which is a current command for one of the plurality of coils 21 included in the conveying path unit 11, is referred to as a current command bundle. The communication master station 45 transmits the current command bundle to the communication sub-station 29 of each conveying path unit 11.

[0051] The current commands generated by the current command generator 42 include a current command in a case where the current flowing through the coil 21 is set to zero. Regarding the expression "generates current commands for performing current control of all of the plurality of coils 21 of each conveying path unit 11," a case where a current command value for at least one of the plurality of coils 21 is set to zero is included.

[0052] Next, details of the processes by the current command generator 42 will be described. Fig. 4 is a flowchart showing a processing procedure by the current command generator 42 of the conveyor system 1 according to the first embodiment. Fig. 4 shows a flow of the processes performed by the current command generator 42 for each control cycle.

[0053] In step S1, the current command generator 42 calculates a bundle of current commands I cmdAbased on the thrust command of the carrier 17A and the position information of the carrier 17A. The bundle of current commands I cmdA is a group of current commands for generating a thrust to move the carrier 17A. The current command generator 42 generates the bundle of current commands I cmdA , in which current commands for all coils 21 of each conveyor path unit 11 are bundled.

[0054] In step S2, the current command generator 42 calculates a bundle of current commands I cmdB based on the thrust command of the carrier 17B and the position information of the carrier 17B. The bundle of current commands I cmdB is a group of current commands for generating a thrust to move the carrier 17B. The current command generator 42 generates the bundle of current commands I cmdB , in which current commands for all coils 21 of each conveyor path unit 11 are bundled.

[0055] In step S3, the current command generator 42 calculates a bundle of current commands I cmdC based on the thrust command of the carrier 17C and the position information of the carrier 17C. The bundle of current commands I cmdC is a group of current commands for generating a thrust to move the carrier 17C. The current command generator 42 generates the bundle of current commands I cmdC , in which current commands for all coils 21 of each conveyor path unit 11 are bundled.

[0056] In step S4, the current command generator 42 calculates a current command for each coil 21 of each conveying path unit 11 using the bundles of current commands I calculated in steps S1 to S3. cmdA , I cmdB and I cmdC . The current command generator 42 adds the current commands for the same coil 21 under the bundles of current commands I cmdA , I cmdB and I cmdC to send a current command I totfor each of the coils 21 of each conveying path unit 11. As described above, the current command generator 42 obtains the current commands for respective carriers 17 for each of the coils 21 and adds the current commands for respective carriers 17 for each of the coils 21 to generate the current command for each coil 21.

[0057] The current command generator 42 generates a bundle of current commands I cmd , in which current commands I tot for all coils 21 of each conveyor path unit 11. The bundle of current commands I cmd is a group of current commands for generating thrusts to move all carriers 17A, 17B and 17C of the conveyor system 1. The current command generator 42 outputs the generated bundle of current commands I cmd Thus, the current command generator 42 terminates the processes according to the Fig. 4. The current command generator 42 repeats the processes according to the Fig. 4 shown procedures for each control cycle.

[0058] This is an example of a method for calculating the bursts of current commands I cmdA , I cmdB and I cmdC by the current command generator 42. In the following description, a current command for each of the coils 21 of each conveying path unit 11 for generating the thrust to move the carrier 17A is referred to as “I cmdA_ Aa" or the like. "Aa" in "I cmdA_ "Aa" indicates that it is the current command for the coil 21a of the conveying path unit 11A. For each coil 21 other than the coil 21a of the conveying path unit 11A, the current command for each of the coils 21 is expressed in the same manner as in the case of the coil 21a of the conveying path unit 11A.

[0059] Fig. 5 is a diagram showing an example of a relationship between a position of the carrier 17 and a thrust constant of the spool 21 in the first embodiment. Fig. Figure 5 shows a graph indicating a relationship between a distance x, which is based on the center position of the coil 21 in the moving direction of the carrier 17, and a thrust constant k(x) of the coil 21. The thrust constant k(x) indicates a relationship between a thrust received from the carrier 17 and a current flowing through the coil 21. In Fig. 5, the vertical axis represents the shear constant k(x) and the horizontal axis represents the distance x. In Fig. 5 is the unit of the shear constant k(x) N / A. In Fig. 5, the unit of distance x is an arbitrary unit. In the following description, the center position of the coil 21 is the center position of the coil 21 in the direction of movement of the carrier 17. The center position of the carrier 17 is the center position of the carrier 17 in the direction of movement of the carrier 17.

[0060] Fig. For reference, Fig. 5 shows the carrier 17 when a front end of the carrier 17 in the moving direction of the carrier 17 coincides with the center position of the coil 21. As the center position of the carrier 17 approaches the center position of the coil 21, a larger thrust can be generated with a smaller current through a relationship between the position of the coil 21 and the phase of the permanent magnet 30. The magnitude of the thrust varies depending on the relationship between the position of the coil 21 and the phase of the permanent magnet 30.

[0061] If the distance x from the center position of the coil 21 to the center position of the carrier 17 is greater than L carrier / 2, which corresponds to a length from the front end of the beam 17 to the center position of the beam 17, the thrust constant becomes zero. That is, if the distance x is greater than L carrier / 2, even if a current is caused to flow through the coil 21, no thrust force is generated that can be exerted on the carrier 17. It should be noted that the Fig. The graph shown in Figure 5 is an example. The relationship between the position of the carrier 17 and the thrust constant of the coil 21 varies depending on how the permanent magnet 30 is arranged.

[0062] In the following description, the thrust constant k(x) for each of the coils 21 of each conveying path unit 11 is expressed as "kAa(x)" or the like. "Aa" in "kAa(x)" indicates that it is the thrust constant k(x) of the coil 21a of the conveying path unit 11A. For each coil 21 other than the coil 21a of the conveying path unit 11A, the thrust constant k(x) for each of the coils 21 is expressed in the same way as for the coil 21a of the conveying path unit 11A.

[0063] Furthermore, in the following description, the center position of each of the coils 21 of each conveying path unit 11 is expressed as "pAa" or the like. "Aa" in "pAa" indicates that it is the center position of the coil 21a of the conveying path unit 11A. For each coil 21 other than the coil 21a of the conveying path unit 11A, the center position for each of the coils 21 is expressed in the same way as for the coil 21a of the conveying path unit 11A.

[0064] The current commands I cmdA_ Aa, I cmdA_ From, ..., I cmdA_ Hh and I cmdA_ The thrust Hi for generating the thrust to move the carrier 17A, each for each of the spools 21 of each conveying path unit 11, is expressed by the following formulas. Note that τA represents a thrust command τ of the carrier 17A. xA is a distance x from the center position of the spool 21 to the center position of the carrier 17A and represents the actual position of the carrier 17A with respect to the spool 21. IcmdA_Aa=kAa(xA−pAa)×τA / {kAa(xA−pAa)2+kAb(xA−pAb)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}IcmdA_Ab=kAb(xA−pAb)×τA / {kAa( xA−pAa)2+kAb(xA−pAb)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}...IcmdA_Hh=kHh(xA−pHh)×τA / {kAa(xA−pAa)2+kAb(xA−pAb)2+...+k Hh(xA−pHh)2+kHi(xA−pHi)2} IcmdA_Hi=kHi(xA−pHi)×τA / {kAa(xA−pAa)2+kAb(xA−pAb)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}

[0065] In general, in a case where the thrust command τ and the thrust constant k(x) are given, there are an infinite number of sets of current commands for each coil 21 that realize the given thrust command τ. A set of current commands I cmdA_ Aa, I cmdA_ From, ... I cmdA_ Hh and I cmdA_ Hi obtained by the above formula is a quantity that minimizes the sum of the squares of the current flowing through the coils 21. That is, according to the above formula, the current commands I cmdA_ Aa, I cmdA_ From, ..., I cmdA_ Hh and I cmdA_Hi, which can minimize the copper loss of the coils 21.

[0066] The current command generator 42 bundles the current commands I cmdA_ Aa, I cmdA_ From,..., I cmdA_ Hh and I cmdA _Hi, in order to thereby the bundle of current commands I cmdA for the carrier 17A.

[0067] Also for the bundle of current commands I cmdB for the carrier 17B and the bundle of current commands I cmdC for the carrier 17C, the current command generator 42 performs a calculation similar to the case of the bundle of current commands I cmdA for the carrier 17A. In the Fig. 4, the calculations are carried out in the order of the bundle of current commands I cmdA , the bundle of current commands I cmdB and the bundle of current commands I cmdC carried out, but the bundle of current commands I cmdA , the bundle of current commands I cmdB and the bundle of current commands I cmdCare calculated in any order.

[0068] Next, an example of a method for calculating the current command I tot for each of the coils 21 of each conveyor path unit 11 for generating thrusts to move the carriers 17A, 17B, and 17C. The current command generator 42 calculates the current command I tot for each of the coils 21 of each conveyor path unit 11 using the bundles of current commands I cmdA , I cmdB and I cmdC . In the following description, the current command I tot for each of the coils 21 of each conveyor path unit 11 as “I tot_ Aa" or the like. "Aa" in "I tot_ Aa” indicates that it is the current command I totfor the coil 21a of the conveying path unit 11A. For each coil 21 other than the coil 21a of the conveying path unit 11A, the current command Itot for each of the coils 21 is expressed in the same manner as in the case of the coil 21a of the conveying path unit 11A.

[0069] The current commands I tot _Aa, I tot _From, ..., I tot _Hh and I tot _Hi, each for one of the coils 21 of each conveying path unit 11, are expressed by the following formulas. Itot_Aa=IcmdA_Aa+IcmdB_Aa+IcmdC_AaItot_Ab=IcmdA_Ab+IcmdB_Ab+IcmdC_Ab...Itot_Hh=IcmdA_Hh+IcmdB_Hh+IcmdC_Hhtot_Hi=IcmdA_Hi+IcmdB_Hi+IcmdC_Hi

[0070] Fig. 6 is a diagram showing examples of calculation results of current commands by the conveyor system 1 according to the first embodiment. Fig. 6 shows examples of calculation results of the current commands I tot_ Aa, I tot_ From, ... I tot_ Hh and I tot_Hi using the calculation method described above.

[0071] As in Fig. 5, the thrust constant k(x) becomes almost zero when the distance x from the center position of the coil 21 to the center position of the carrier 17 is close to L carrier / 2, and the current flowing through the coil 21 hardly contributes to generating the thrust of the carrier 17. Therefore, for example, in a case where I cmdA _Aa is a non-zero value, both I cmdB_ Aa as well as I cmdC_ Aa almost zero, and I tot_ Aa=I cmdA_ Aa essentially holds. As described above, it follows that the number of supports 17 to which each coil 21 can exert thrust is essentially one, and one coil 21 does not exert thrust on two or more supports 17 simultaneously.

[0072] In addition, if the conveyor system 1 is in the Fig. 1, for example, in the conveying path unit 11B, there is no coil 21 whose distance x is shorter than Lcarrier / 2. For the coil 21d, which is one of the plurality of coils 21 provided in the conveying path unit 11B as an example, a current command I tot_ Bd of coil 21d is calculated as follows: Itot_Bd=IcmdA_Bd+IcmdB_Bd+IcmdC_Bd=0×τA / {kAa(xA−pAa)2+kAb(xA−pAa)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}+0×τB / {kAa(xA−p Aa)2+kAb(xA−pAb)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}+0×τC / {kAa(xA−pAa)2+kAb(xA−pAb)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}=0

[0073] As described above, in a case where there is no coil 21, its distance x is shorter than L carrier / 2, the current command value for the coil 21 is calculated as zero. That is, the current command generator 42 generates a current command in which the current command value for the coil 21 is set to zero at a position other than the position where the thrust can be applied to the carrier 17.

[0074] As described above, the current command generator 42 generates the current commands I tot_ Aa, I tot_ From, ..., I tot_ Hh and I tot_ Hi for all coils 21a, 21b, ... and 21i of the conveying path units 11A, 11B, ... and 11H. The current command generator 42 generates current commands for performing current control of all of the plurality of coils 21 of each conveying path unit 11 in all control cycles in controlling the plurality of conveying path units 11.

[0075] The current command generator 42 generates the bundle of current commands I cmd , in which the current commands I tot_ Aa, I tot_ From, ..., I tot_ Hh and Itot_ Hi are bundled. The current command generator 42 outputs the generated bundle of current commands I cmd to the communication main station 45. For example, the communication main station 45 transmits the current commands I tot_ Aa, I tot_ From, ... and I tot_ Ai from the bundle of current commands I cmd to the communication substation 29 of the conveyor path unit 11A. The communication main station 45 transmits the current commands I tot_ Ha, I tot_ Hb, ... and I tot_ Hi from the bundle of current commands I cmd to the communication substation 29 of the conveyor path unit 11H. As described above, the communication master station 45 transmits the current commands to the communication substation 29 of each conveyor path unit 11.

[0076] According to the first embodiment, the current command generator 42 of the conveyor system 1 generates current commands for performing current control of all of the plurality of coils 21 of each conveyor path unit 11 in each control cycle when controlling the plurality of conveyor path units 11. The conveyor system 1 sends current commands not only for the coil 21 at a position where thrust can be applied to the carrier 17, but also for all coils 21 including the coil 21 at a position other than the position where thrust can be applied to the carrier 17. Since the conveyor system 1 does not require a switch that switches between supplying current to the coils 21 and cutting off the current flowing to the coils 21, a circuit configuration can be simplified.Furthermore, since the conveyor system 1 does not need to generate and output an opening / closing command for the switch separately from the current commands, it is possible to perform the control by a simple program.

[0077] In a case where the coil 21 to be supplied with current is selected from the plurality of coils 21 of each conveying path unit 11, the current command is calculated only for the selected coil 21. On the other hand, in the case of the first embodiment, since the current command generator 42 uniformly generates the current commands for all the coils 21 of each conveying path unit 11, a process for selecting the coil 21 and calculating the current command only for the selected coil 21 is unnecessary. As a result, the conveying system 1 can control each conveying path unit 11 by a simple process.

[0078] The current command generator 42 generates a current command in which the current command value for the coil 21 is set to zero at a position other than the position where the thrust can be applied to the carrier 17. Even if an induced current can be generated in the coil 21 at a position other than the position where the thrust can be applied to the carrier 17, the conveyor system 1 can make an adjustment to bring the current to zero by canceling the induced current. In the conveyor system 1, it is not necessary to perform a case-by-case check for processes that depend on the presence or absence of the carrier 17 at the position where the thrust can be applied thereto, and the flow of the processes can be simplified.

[0079] Thus, the conveyor system 1 achieves the effect that a circuit configuration can be simplified and the control can be performed by simple methods. Second embodiment.

[0080] In the first embodiment, the current command generator 42 obtains the current commands for respective carriers 17 for each of the coils 21 and adds the current commands for respective carriers 17 for each of the coils 21 to generate the current command for each coil 21. In a second embodiment, for each coil 21, the current command generator 42 selects a carrier 17 from the plurality of carriers 17 that is closest to the coil 21 and obtains a current command that applies a thrust to the selected carrier 17, thereby generating a current command for each coil 21. In the second embodiment, the same components as in the first embodiment are denoted by the same reference numerals as in the first embodiment, and configurations different from those in the first embodiment will be mainly described.

[0081] Fig. 7 is a diagram showing an exemplary configuration of the conveyance path unit 11 included in the conveyance system 1 according to the second embodiment. Fig. 7 shows part of the configuration of the conveyor path unit 11 and two carriers 17A and 17B. Fig. 7 shows a case where two carriers 17A and 17B are provided on the conveying path unit 11A, which is one of the plurality of conveying path units 11 of the conveying system 1. In the conveying system 1, in addition to the case where two carriers 17 are provided on one conveying path unit 11, as shown in Fig. 7, a case where a carrier 17 is present on a conveying path unit 11 and a case where no carrier 17 is present on a conveying path unit 11.

[0082] In the Fig. 7, the carrier 17 located at the position closest to the center position of the coil 21a in the direction of movement of the carrier 17 is the carrier 17A. Using τA, the thrust command τ for the carrier 17A, and xA, the distance x for the carrier 17A, the current command generator 42 calculates the current command I tot_Aa for the coil 21a of the conveying path unit 11A according to the following formula. Itot_Aa=IcmdA_Aa=kAa(xA−pAa)×τA / {kAa(xA−pAa)2+kAb(xA−pAb)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}

[0083] In a case other than that in Fig. In the case shown in Figure 7, when the carrier 17 is present at a position far from the center position of the coil 21a, kAa(xA-pAa)=0 according to the equation shown in Fig. 5. In this case, the coil 21a does not generate the thrust that can be exerted on the carrier 17.

[0084] In the Fig. For example, in the state shown in Figure 7, the carrier 17 located at the position closest to the center position of the coil 21e in the direction of movement of the carrier 17 is the carrier 17B. Using τB, the thrust command τ for the carrier 17B, and xB, the distance x for the carrier 17B, the current command generator 42 calculates the current command I tot_Ae for the coil 21e of the conveying path unit 11A according to the following formula. Itot_Ae=IcmdA_Ae=kAe(xB−pAe)×τB / {kAa(xB−pAa)2+kAb(xB−pAb)2+...+kHh(xB−pHh)2+kHi(xB−pHi)2}

[0085] In the Fig. For example, in the state shown in Figure 7, the carrier 17 located at the position closest to the center position of the coil 21d in the direction of movement of the carrier 17 is the carrier 17A. Using τA, the thrust command τ for the carrier 17A, and xA, the distance x for the carrier 17A, the current command generator 42 calculates the current command I tot_Ad for the coil 21d of the conveying path unit 11A according to the following formula. Itot_Ad=IcmdA_Ad=kAd(xA−pAd)×τA / {kAa(xA−pAa)2+kAb(xA−pAb)2+...+kHh(xA−pHh)2+kHi(xA−pHi)2}

[0086] In the Fig. In the state shown in Figure 7, a part of the carrier 17B is also present on the coil 21d. However, since the distance x from the center position of the coil 21d to the center position of the carrier 17 is longer than the length from the front end of the carrier 17B to the center position of the carrier 17B, the thrust constant of the thrust that can be exerted by the coil 21d on the carrier 17B is determined according to the Fig. 5 is almost zero. Since a magnetic flux generated by the coil 21d hardly contributes to the movement of the carrier 17B, the current command I based on τA and xA cmdA_ Ad for the carrier 17A unchanged as current command I tot_ Ad can be used for coil 21d.

[0087] Fig. 8 is a diagram showing an example of a thrust command used to generate a current command for each coil 21 in the conveyor system 1 according to the second embodiment. Fig. 8 shows for each of the coils 21a to 21i in the Fig. 7, the carrier 17 closest to the center position of the coil 21 and the thrust command τ used to generate the current command. For the coils 21a to 21d, the carrier 17 closest to the center position of the coil 21 is the carrier 17A. The thrust command τ used to generate the current command for each of the coils 21a to 21d is τA. As for the coils 21e to 21i, the carrier 17 closest to the center position of the coil 21 is the carrier 17B. The thrust command τ used to generate the current command for each of the coils 21e to 21i is τB.

[0088] As described above, the current command generator 42 selects a carrier 17 closest to the coil 21 among the plurality of carriers 17 for each coil 21 and obtains a current command that applies a thrust force to the selected carrier 17, thereby generating a current command for each coil 21. The current command generator 42 also calculates a current command for each coil 21 of each of the conveying path units 11B to 11H, similarly to the current command for each coil 21 of the conveying path unit 11A.

[0089] The current command generator 42 generates the bundle of current commands I cmd , in which current commands for the coils 21 of each conveyor path unit 11 are bundled. The current command generator 42 outputs the generated bundle of current commands Icmd to the communication master station 45. For example, the communication master station 45 transmits the current commands I tot_ Aa, I tot_ From, ... and I tot_ Ai from the current command bundle I cmdto the communication substation 29 of the conveyor path unit 11A. The communication main station 45 transmits the current commands I tot_ Ha, I tot_ Hb, ... and I tot_ Hi from the bundle of current commands I cmd to the communication substation 29 of the conveyor path unit 11H. As described above, the communication master station 45 transmits the current commands to the communication substation 29 of each conveyor path unit 11.

[0090] According to the second embodiment, the current command generator 42 of the conveyor system 1 generates current commands for performing current control of all of the plurality of coils 21 of each conveyor path unit 11 in each control cycle when controlling the plurality of conveyor path units 11. Consequently, the conveyor system 1 achieves the effect of simplifying the circuit configuration and performing control through simple processes.

[0091] Furthermore, for each coil 21, the current command generator 42 selects a carrier 17 from the plurality of carriers 17 that is closest to the coil 21 and obtains a current command that applies a thrust force to the selected carrier 17. Since the current command generator 42 calculates the current command corresponding to the selected carrier 17 for each coil 21, the computational burden can be reduced compared to the case of calculating the current command corresponding to each of the plurality of carriers 17 for each coil 21. Consequently, the conveyor system 1 can reduce the computational burden for control. Third embodiment.

[0092] In a third embodiment, an example will be described in which a thrust command is corrected based on a thrust command correction value, and machine learning is applied to the calculation of the thrust command correction value. In the third embodiment, the same components as in the first or second embodiment are denoted by the same reference numerals as those in those embodiments, and configurations different from those in the first or second embodiment will be mainly described.

[0093] In each conveying path unit 11, the coils 21 are arranged at regular intervals, but the continuity of the arrangement of the coils 21 is interrupted at a connecting portion between the conveying path units 11 in the conveying path 10. Therefore, a cogging torque different from a cogging torque generated between the coils 21 in the conveying path unit 11 is generated at the connecting portion between the conveying path units 11, and the cogging torque fluctuates. Since the alignment of the conveying path units 11 is often performed by a user and misalignment between the conveying path units 11 is likely to occur, it is difficult to predetermine a correction value for correcting the cogging torque at the connecting portion between the conveying path units 11.In a case where the correction value is obtained after the actual completion of the assembly of the conveyor path 10, it is necessary to accurately measure the cogging torque at the connecting portion between the conveyor path units 11, so that the number of man-hours in the assembly of the conveyor path 10 increases.

[0094] In the third embodiment, by calculating the thrust command correction value calculated by machine learning to correct the thrust command, the cogging torque can be corrected with high accuracy, and the number of man-hours in assembling the conveyor path 10 can be reduced. In the third embodiment, the thrust command correction value is a correction value used to correct the thrust command.

[0095] Fig. 9 is a diagram showing an exemplary configuration of a track controller 50 included in the conveyor system 1 according to the third embodiment. The track controller 50 includes the current command generator 42, the position information generator 43, the communication substation 44, the communication master station 45, a carrier position controller 51, a learning device 52, and a learned model storage unit 53.

[0096] The carrier position controller 51 acquires a position command of each carrier 17 and position information of each carrier 17. The carrier position controller 51 generates a thrust command of each carrier 17 based on a difference between the position command and the position information. In addition, the carrier position controller 51 acquires a learned model from the learned model storage unit 53 and obtains the thrust command correction value based on the learned model and the position information of each carrier 17. The carrier position controller 51 corrects the thrust command using the thrust command correction value and outputs the corrected thrust command to the current command generator 42.

[0097] The learning device 52 obtains the position information and the thrust command correction value of each carrier 17. The learning device 52 learns a thrust command correction value that enables highly accurate correction of the cogging torque. The learning device 52 outputs a learned model, which is a result of the learning. The learned model storage unit 53 stores the learned model.

[0098] Fig. 10 is a diagram showing an exemplary configuration of the learning device 52 included in the conveyor system 1 according to the third embodiment. The learning device 52 includes a data acquisition unit 61 and a model generation unit 62. The data acquisition unit 61 acquires learning data and creates a data set obtained by combining the learning data. The learning data is position information and a push command correction value of each carrier 17. That is, the data acquisition unit 61 acquires learning data including the position information and the push command correction value. The data acquisition unit 61 obtains the position information from the position information generator 43. The data acquisition unit 61 acquires the push command correction value from the carrier position controller 51.

[0099] The model generation unit 62 generates a learned model using the learning data. The model generation unit 62 generates a learned model to be used for inferring a thrust command correction value from position information based on the learning data. The model generation unit 62 outputs the generated learned model. The learned model is stored in the learned model storage unit 53. Note that the model generation unit 62 may read an already generated learned model from the learned model storage unit 53 and update the learned model by relearning according to the learning data.

[0100] As the learning algorithm used by the model generation unit 62, a well-known algorithm such as supervised learning, unsupervised learning, or reinforcement learning can be used. As an example, a case where reinforcement learning is applied to a learning algorithm used by the model generation unit 62 will be described. Reinforcement learning is learning in which an action subject, as an agent, observes the current state in an environment and decides which action to perform. The agent receives a reward from the environment by selecting an action and learns a strategy for achieving maximum reward through a series of actions. As representative methods of reinforcement learning, Q-learning, TD learning, and the like are well-known.For example, in the case of Q-learning, an action value table, which is a general update formula for an action value function Q(s, a), is expressed by the following formula (1). The action value function Q(s, a) specifies an action value Q, which is a value of an action of selecting an action "a" under an environment "s". Formula 1: Q(st,at)←Q(st,at)+α(rt+1+γmaxaQ(st+1,at)−Q(st,at))

[0101] In formula (1) “s t ” for an environment at time “t”. “a t “ represents an action at time “t”. The action “at” changes the environment to “s t+1 ". "r t+1 " stands for a reward given by the change in the environment. "γ" stands for a discount rate. "α" stands for a learning coefficient. In the third embodiment, the position information is the environment "s t The thrust command correction value is the action “a t “.

[0102] The update formula expressed by formula (1) increases an action value Q when an action value of the best action "a" at time "t+1" is greater than an action value Q of the action "a" executed at time "t", and decreases the action value Q when the opposite is true. In other words, the action value function Q(s,a) is updated so that the action value Q of the action "a" at time "t" approaches a best action value at time "t+1". Consequently, a best action value in a certain environment is sequentially propagated to action values ​​in the previous environments.

[0103] The model generation unit 62 includes a reward calculation unit 63 and a function update unit 64. The reward calculation unit 63 calculates a reward based on the data set. The function update unit 64 updates a function for determining a thrust command correction value in accordance with the reward calculated by the reward calculation unit 63.

[0104] Specifically, the reward calculation unit 63 calculates a reward "r" based on the variability of the speed of the carrier 17. The variability of the speed of the carrier 17 is obtained, for example, based on the position information of the carrier 17. For example, when the variability of the speed of the carrier 17 becomes small, the reward calculation unit 63 increases the reward "r." The reward calculation unit 63 increases the reward "r" by specifying "1," which is a reward value. Note that the reward value is not limited to "1." On the other hand, when the variability of the speed of the carrier 17 becomes large, the reward calculation unit 63 decreases the reward "r." The reward calculation unit 63 decreases the reward "r" by specifying "-1," which is a reward value. Note that the reward value is not limited to "-1."

[0105] The function updating unit 64 updates a function, which is a model for determining a thrust command correction value according to the reward calculated by the reward calculating unit 63. The function can be updated according to the data set, for example, by updating the action value table. The action value table is a data set in which each action and an action value thereof are stored in a linked table. For example, in the case of Q-learning, an action value function Q(s t ,a t ), expressed by the above formula (1), is used as a function to determine the thrust command correction value.

[0106] Fig. Fig. 11 is a flowchart showing a processing method of the learning device 52 included in the conveyor system 1 according to the third embodiment. A reinforcement learning method for updating the action value function Q(s,a) will be described with reference to the flowchart of Fig. 11 described.

[0107] In step S11, the learning device 52 acquires position information and a thrust command correction value of each carrier 17 via the data acquisition unit 61. That is, the learning device 52 acquires learning data. The data acquisition unit 61 outputs a data set including the learning data to the model generation unit 62.

[0108] In step S12, the learning device 52 calculates a reward through the reward calculation unit 63. The reward calculation unit 63 calculates a reward for a combination of the position information of each carrier 17 and the thrust command correction value for each carrier 17. The reward calculation unit 63 increases or decreases the reward based on the variability of the speed of the carrier 17.

[0109] In step S13, the learning device 52 updates the action value function through the function updating unit 64. The function updating unit 64 updates the action value function Q(s,a) based on the reward calculated in step S12. The learning device 52 updates the action value function Q(s t ,a t ) stored in the learned model storage unit 53.

[0110] In step S14, the learning device 52 determines whether the action value function Q(s,a) has converged through the function updating unit 64. The function updating unit 64 determines that the action value function Q(s,a) has converged when the action value function Q(s,a) is no longer updated in step S13.

[0111] If the function updating unit 64 determines that the action value function Q(s,a) has not converged (step S14, No), the learning device 52 returns to step S11. On the other hand, if the function unit 64 determines that the action value function Q(s,a) has converged (step S14, Yes), the learning device 52 terminates the processes according to the Fig. 11. Note that the learning device 52 may continue learning by returning the process from step S13 to step S11 without making the determination in step S14. The learned model storage unit 53 stores a learned model that is the generated action value function Q(s,a).

[0112] In the third embodiment, the case where reinforcement learning is applied to the learning algorithm used by the learning device 52 was described, but learning other than reinforcement learning may also be applied to the learning algorithm. The learning device 52 can perform machine learning using a known learning algorithm other than reinforcement learning, for example, a learning algorithm such as deep learning, a neural network, genetic programming, inductive logic programming, or a support vector machine.

[0113] The Fig. 9 and Fig. The learning device 52 shown in Figure 10 is a device built into the track controller 50. The learning device 52 may be a device external to the track controller 50. The learning device 52, which is a device external to the track controller 50, constitutes the conveyor system 1. The learning device 52 may be a device that can be connected to the track controller 50 via a network. The learning device 52 may be a device that exists on a cloud server.

[0114] The learning device 52 can learn a relationship between the position information and the push command correction value according to a data set created for a plurality of conveyor systems 1. The learning device 52 can acquire learning data from a plurality of conveyor systems 1 used at the same location, or acquire learning data from a plurality of conveyor systems 1 used at different locations. The learning data can be acquired from a plurality of conveyor systems 1 operating independently of each other at a plurality of locations. After the collection of learning data from such a plurality of conveyor systems 1 has begun, a new conveyor system 1 can be added as a target from which the learning data is collected. Furthermore, after the collection of learning data from the plurality of conveyor systems 1 has begun, some of the plurality of conveyor systems 1 can be excluded from targets from which the learning data is collected.

[0115] The learning device 52 that has learned one conveyor system 1 can learn a conveyor system 1 other than the one conveyor system 1. The learning device 52 that performs learning for the other conveyor system 1 can update the learned model by relearning in the other conveyor system 1.

[0116] Fig. 12 is a diagram showing an exemplary configuration of the carrier position controller 51 included in the conveyor system 1 according to the third embodiment. The carrier position controller 51 includes a push command generator 71, a push command correction unit 72, a data acquisition unit 73, and an inference unit 74. The data acquisition unit 73 and the inference unit 74 function as an inference device that infers a push command correction value from the position information of each carrier 17.

[0117] The thrust command generator 71 acquires a position command of each carrier 17 and position information of each carrier 17. The thrust command generator 71 generates a thrust command for each carrier 17 based on a difference between the position command for each of the carriers 17 and the position information for each of the carriers 17. The thrust command generator 71 outputs the generated thrust command to the thrust command correction unit 72.

[0118] The data acquisition unit 73 acquires inference data. The inference data is position information of each of the plurality of carriers 17 included in the conveyor system 1. The data acquisition unit 73 obtains the position information from the position information generator 43. The inference unit 74 reads the learned model generated by the learning device 52 from the learned model storage unit 53. The inference unit 74 infers the push command correction value by inputting the inference data into the learned model. The inference unit 74 outputs the push command correction value, which is a result of the inference, to the push command correction unit 72. The push command correction unit 72 corrects the push command of each carrier 17 using the push command correction value. The push command correction unit 72 outputs the corrected push command.

[0119] Fig. 13 is a flowchart showing a processing method of the carrier position controller 51 included in the conveyor system 1 according to the third embodiment. The carrier position controller 51 acquires a position command of each carrier 17 and position information of each carrier 17 through the push command generator 71. The push command generator 71 generates a push command of each carrier 17 based on the position command and the position information.

[0120] In step S21, the carrier position controller 51 acquires the position information of each carrier 17 through the data acquisition unit 73. The data acquisition unit 73 outputs the acquired position information to the inference unit 74. In step S22, the carrier position controller 51 generates a thrust command correction value through the inference unit 74 by inputting the position information into the learned model. The inference unit 74 outputs the generated thrust command correction value to the thrust command correction unit 72.

[0121] In step S23, the carrier position controller 51 corrects the thrust command using the thrust command correction value by the thrust command correction unit 72. In step S24, the carrier position controller 51 outputs the thrust command corrected by the thrust command correction unit 72. Thus, the carrier position controller 51 terminates the processes according to the Fig. 13. The current command generator 42 generates a current command based on the thrust command and the position information of each carrier 17 acquired by the carrier position controller 51.

[0122] According to the third embodiment, the conveyor system 1 learns the push command correction value through the learning device 52, which enables highly accurate correction of the cogging torque. Since the carrier position controller 51 includes the data acquisition unit 73 and the inference unit 74, the conveyor system 1 infers the push command correction value, which enables highly accurate correction of the cogging torque. In the conveyor system 1, by correcting the push command based on the push command correction value resulting from the inference, the cogging torque can be corrected with high accuracy, and the number of man-hours required for assembling the conveyor path 10 can be reduced.

[0123] Next, hardware implementing the tracking controllers 20 and 50 according to the first to third embodiments will be described. The tracking controllers 20 and 50 are implemented by a processing circuit. The processing circuit may be a circuit in which a processor executes software or a dedicated circuit.

[0124] In a case where the processing circuit is implemented by software, the processing circuit is, for example, a Fig. Control circuit shown in Figure 14. Fig. 14 is a diagram showing an exemplary configuration of a control circuit 80 according to the first to third embodiments. The control circuit 80 includes an input unit 81, a processor 82, a memory 83, and an output unit 84. The input unit 81 is an interface circuit that receives data input from outside the control circuit 80 and transmits the data to the processor 82. The output unit 84 is an interface circuit that sends data from the processor 82 or the memory 83 to the outside of the control circuit 80.

[0125] In a case where the processing circuitry of the Fig. 14, the tracking controllers 20 and 50 are implemented by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 83. The processing circuit implements functions of the tracking controllers 20 and 50 by the processor 82 reading and executing a program stored in the memory 83. That is, the processing circuit includes the memory 83 for storing a program that results in executing a process of each of the tracking controllers 20 and 50. It can be concluded that these programs cause a computer to execute methods and procedures of the tracking controllers 20 and 50.

[0126] The processor 82 is a CPU. The processor 82 may be a central processing device, a processing device, an arithmetic device, a microprocessor, a microcomputer, a processor, or a DSP. The memory 83 corresponds, for example, to a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an electrically erasable programmable read-only memory (EEPROM (registered trademark)), a magnetic disk, a flexible disk, an optical disk, a compact disc, a mini disc, or a DVD (Digital Versatile Disc).

[0127] Fig. 14 is a hardware example in a case where the tracking controllers 20 and 50 are respectively realized by the processor 82 and the memory 83 for general use, wherein the tracking controllers 20 and 50 may each be realized by a dedicated hardware circuit. Fig. 15 is a diagram showing an exemplary configuration of a hardware circuit 85 as a dedicated circuit according to the first to third embodiments.

[0128] The hardware circuit 85 as a dedicated circuit includes the input unit 81, the output unit 84, and a processing circuit 86. The processing circuit 86 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a circuit obtained by combining them. Functions of the tracking controllers 20 and 50 can be realized separately by the processing circuit 86, or the functions can be realized collectively by the processing circuit 86. Note that the tracking controllers 20 and 50 can be realized by combining the control circuit 80 and the hardware circuit 85.

[0129] The Fig. The motion controller 19 shown in Figure 1 is implemented by a processing circuit similar to the track controllers 20 and 50. The processing circuit implementing the motion controller 19 is the one shown in Fig. 14 or the control circuit shown in Fig. 15 as a dedicated circuit.

[0130] Specific distributed or integrated modes of the components in the conveyor system 1 according to the first to third embodiments are not limited to those described in the first to third embodiments. All or some of the components of the conveyor system 1 can be configured to be functionally or physically distributed or integrated in each unit. For example, the Fig. 1 is not limited to the motion controller 19 and the tracking controller 20, which are separated from each other, and can be realized by one device.

[0131] The configurations described above in the respective embodiments are merely examples of the content of the present disclosure. The configurations of the respective embodiments can be combined with other known technologies. The configurations of the respective embodiments can be combined as appropriate. Part of the configurations of the respective embodiments may be omitted or modified without departing from the gist of the present disclosure. List of reference symbols 1 conveyor system; 10 funding path; 11, 11A-11H conveyor path unit; 12 Control; 13 DC power supply; 14, 15 data communication line; 16 DC power supply bus; 17, 17A, 17B, 17C carriers; 18A, 18B arrow; 19 motion control; 20, 50 lane control; 21, 21a-21i coil; 22 inverter circuit; 23 current sensor; 24 capacitor; 25 power control; 26 linear scale; 27 Position sensor; 28 , 82 processor; 29, 44 Communications substation; 30, 31 permanent magnet; 41, 51 carrier position control; 42 current command generators; 43 position information generators; 45 Communications main station; 52 learning device; 53 Storage unit for learned models; 61, 73 data acquisition unit; 62 model generation unit; 63 Reward calculation unit; 64 Function Update Unit; 71 thrust command generator; 72 thrust command correction unit; 74 Inference unit; 80 control circuit; 81 input unit; 83 storage; 84 output unit; 85 hardware circuit; 86 processing circuit. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2017-79569

[0004]

Claims

[1] Conveyor system comprising: a plurality of conveying path units forming a conveying path along which a conveying body moves, wherein each of the conveying path units comprises a plurality of drive units, each generating a thrust for moving the conveying body by a current flowing therethrough; and a controller having a current command generator that generates a current command for controlling a current flowing through the plurality of drive units, wherein each of the plurality of conveying path units controls the current flowing through each of the plurality of drive units in accordance with the current command, and wherein the current command generator generates a current command for performing current control of all of the plurality of drive units of each of the conveying path units at each control cycle when the current command is generated. [2] The conveyor system according to claim 1, wherein an arrangement pitch of the plurality of drive units in a moving direction of the conveyor body is shorter than a length of the conveyor body in the moving direction. [3] Conveyor system according to claim 1 or 2, comprising: the conveyor body, of which there are one or more units, wherein the conveyor body is provided with a permanent magnet and wherein the drive unit comprises a coil generating an electromagnetic force which is the thrust by an interaction between a current and a magnetic field generated by the permanent magnet. [4] Conveyor system according to claim 3, wherein a length of the permanent magnet in a moving direction of the conveyor body is shorter than a length of the conveyor body in the moving direction. [5] Conveyor system according to one of claims 1 to 4, wherein the plurality of conveying path units move each of the plurality of conveying bodies by applying the thrust to each of the plurality of conveying bodies, and wherein the current command generator receives a current command for each of the conveyor bodies for each of the drive units and adds current commands for the conveyor bodies for each of the drive units to generate a current command for each of the drive units. [6] Conveyor system according to one of claims 1 to 4, wherein the plurality of conveying path units move each of the plurality of conveying bodies by applying the thrust to each of the plurality of conveying bodies, and wherein the current command generator selects, for each of the drive units, one of the conveyor bodies that is closest to the drive unit among the plurality of conveyor bodies and receives a current command that applies the thrust to the selected conveyor body, thereby generating a current command for each of the drive units. [7] The conveyor system according to any one of claims 1 to 6, wherein the controller generates a thrust command for the conveyor body based on a position command indicating a position to which the conveyor body is moved and position information indicating a result of detecting the position of the conveyor body, and generates the current command based on the thrust command and the position information. [8] Conveyor system according to claim 7, comprising: a data acquisition unit for acquiring learning data including a correction value used to correct the thrust command and the position information; and a model generation unit for generating a learned model used for inference of the correction value from the position information based on the learning data, wherein the controller corrects the thrust command based on the correction value inferred using the learned model, and wherein the current command generator generates the current command based on the corrected thrust command and the position information.

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