Funding system

Abstract

Conveyor system (1) with a plurality of conveying path units (11A to 11H) forming a conveying path (10) along which one or a plurality of conveying bodies move, wherein the plurality of conveying path units (11A to 11H) each comprise: a plurality of drive units to be supplied with energy in order to generate a thrust force that moves the conveying body; and a processor (27) for determining whether each of the plurality of drive units is in an overload state, and also for determining whether the conveyor path unit (11) is in an overload state, and wherein in each of the plurality of conveyor path units (11A to 11H) the processor (27) performs an overload protection processing which reduces a temperature of the drive unit which is determined to be in the overload state, or a temperature of the conveyor path unit (11) which is determined to be in the overload state.

Description

Technical field

[0001] The present disclosure relates to a funding system that funds an object. background

[0002] A production line equipped with factory automation, such as one for assembling an industrial product or packaging a food product, generally uses a conveyor system to transport workpieces. In this type of conveyor system, widely adopted in recent years, the conveyor path is divided into multiple zones, and a carrier transporting the workpiece is moved by a control system located in each zone. Such a conveyor system is known for its high production efficiency.

[0003] One type of conveying system used is a so-called linear motor with a movable magnet, in which a magnet is arranged as the rotor on the carrier and coils are arranged on a stator that forms the conveying path. The linear motor with a movable magnet is suitable for moving the rotor over a stroke that is longer than the length of the rotor itself. A plurality of coils are arranged along the conveying path in the direction in which the rotor moves.

[0004] Patent literature 1 discloses a system comprising a carrier as a conveying body and a plurality of coils arranged on a conveying path, wherein the carrier is moved by the action of a magnetic field generated by passing a current through the coils.

[0005] Patent literature 2 discloses a motion control system with a linear motor and an acceleration control means to suppress excessive heat generation of the linear motor.

[0006] Patent literature 3 discloses an overload protection device for motors, which includes an operating stop time temperature storage means to ensure motor performance in an overload condition.

[0007] Patent literature 4 discloses a drive device comprising an overload detection circuit to control a motor at an overloaded speed. List of patent literature Patent Literature 1: JP S61 - 173 607 A; Patent literature 2: JP 2010 - 68 588 A; Patent literature 3: JP 2012 - 95 415 A and Patent literature 4: JP 2013 - 212 018 A Overview of the invention Problem to be solved by the invention

[0008] The system disclosed in patent literature 1 implements overload protection to prevent problems such as burnout due to overheating when driving a linear motor. In the linear motor, the coils can be a heat source due to losses.

[0009] In a linear motor that moves the carrier over a stroke longer than the carrier's length, the carrier can be moved without a reduction in the rated thrust if the rated current flows only to the coil in the area where the carrier is located among the majority of coils arranged along the conveying path. In other words, a conveying system with such a linear motor rarely operates in a scenario where the rated current constantly flows through all coils along the conveying path. If such a conveying system is equipped with an overload protection function designed to resolve an overload condition in a case where the rated current constantly flows through most coils, the overload protection's capacity exceeds the capacity suitable for the conveying system's operation.Excessive overload protection leads to an unnecessarily complex overload protection configuration, which increases the cost of the conveyor system. Therefore, it is desirable for the conveyor system to implement overload protection appropriate for its operation.

[0010] The present disclosure was made in view of the foregoing, and one objective of the present disclosure is to provide a conveying system that can implement overload protection suitable for the operation of the conveying system. Means to solve the problem

[0011] To solve the problems described above and achieve the objective, a conveying system according to the present disclosure comprises a plurality of conveying path units forming a conveying path along which one or more conveyed bodies move. Each of the plurality of conveying path units comprises a plurality of drive units supplied with energy to generate a thrust force for moving the conveyed body, and a processor that determines whether each of the plurality of drive units is in an overload state, and also determines whether the conveying path unit is in an overload state. In each of the plurality of conveying path units, the processor performs overload protection processing that reduces the temperature of the drive unit determined to be in an overload state, or the temperature of the conveying path unit determined to be in an overload state. Effects of the invention

[0012] The conveying system according to the present disclosure can implement an overload protection suitable for the operation of the conveying system. Brief description of the drawings Fig. Figure 1 is a diagram showing an exemplary configuration of a conveying system according to a first embodiment. Fig. Figure 2 is a diagram showing an exemplary configuration of a conveying path unit included in the conveying system according to the first embodiment. Fig. Figure 3 is a graph illustrating the thermal resistance of a component that forms a drive unit in the conveying system according to the first embodiment. Fig. Figure 4 is a graph showing an example of a first overload determination curve, which serves as a first criterion for an overload condition in the conveying system according to the first embodiment. Fig. Figure 5 is a first diagram to illustrate a worst loss of the conveying path unit in the conveying system according to the first embodiment. Fig. Figure 6 is a second diagram to illustrate the worst loss of the conveying path unit in the conveying system according to the first embodiment. Fig. Figure 7 is a graph showing an example of a second overload determination curve, which serves as a second criterion for the overload condition in the conveying system according to the first embodiment. Fig. Figure 8 is a first diagram to illustrate a maximum nominal loss of the conveying path unit in the conveying system according to the first embodiment. Fig. Figure 9 is a second diagram to illustrate the maximum nominal loss of the conveying path unit in the conveying system according to the first embodiment. Fig. Figure 10 is a diagram showing an exemplary configuration of a control system included in a conveying system according to a fourth embodiment. Fig. Figure 11 is a diagram showing an exemplary configuration of a learning device included in the control system according to the fourth embodiment. Fig. Figure 12 is a flowchart showing a processing sequence of the learning device included in the controller according to the fourth embodiment. Fig. Figure 13 is a diagram showing an exemplary configuration of an operating command generation means included in the control system according to the fourth embodiment. Fig. Figure 14 is a flowchart showing a processing sequence of the operating command generation means, a position command generation means and a coil drive command generation means according to the fourth embodiment, which are included in the control. Fig. Figure 15 is a diagram showing an exemplary configuration of a control circuit according to the first to fourth embodiments. Fig. Figure 16 is a diagram showing an exemplary configuration of a hardware circuit intended for use according to the first to fourth embodiments. Description of the embodiments

[0013] The following section describes in detail a conveying system according to embodiments with reference to the drawings. First embodiment.

[0014] Fig. Figure 1 is a diagram showing an exemplary configuration of a conveying system 1 according to a first embodiment. The conveying system 1 is a system used to convey an object. In the first embodiment, the conveying system 1 conveys the object by moving a conveying body that carries the object.

[0015] The conveyor system 1 comprises several conveyor path units 11A to 11H, a controller 12, a DC power supply 13, and carriers 16A, 16B, and 16C. The controller 12 controls the operation of the carriers 16A, 16B, and 16C via the conveyor path units 11A to 11H. In the following description, a conveyor path unit 11 refers to any of the conveyor path units 11A to 11H, without distinguishing between them.

[0016] The multiple conveyor path units 11 are coupled together to form a conveyor path 10 along which the conveyed body moves. The multiple conveyor path units 11 move the conveyed body by applying force to it. Each of the carriers 16A, 16B, and 16C is the conveyed body. In the following description, a carrier 16 refers to each of the carriers 16A, 16B, and 16C without distinguishing between them.

[0017] The in Fig. The conveying path shown in 10 is ring-shaped. That is, the one in Fig. The conveying path 10 shown is a closed path. Conveying path 10 of conveying system 1 can also be an open path. That is, conveying path 10 of conveying system 1 can be a path with a starting point and an endpoint that are located apart.

[0018] Conveyor path units 11A, 11B, 11E, and 11F are each linear conveyor path unit 11, forming a linear path. Conveyor path units 11C, 11D, 11G, and 11H are each curved conveyor path unit 11, forming a curved path, thus changing the direction of movement of the conveyed object. Conveyor path 10 can consist solely of the curved conveyor path unit 11, without including the linear conveyor path unit 11. Conveyor path 10 with a start and end point that are spaced apart can consist solely of the linear conveyor path unit 11. The overall shape of conveyor path 10 is arbitrarily determined.

[0019] The carrier 16 is attached to a side face of the conveyor path 10. The carrier 16 moves along a guide rail provided on the side face of the conveyor path 10. The carrier 16 moves along the side face of the conveyor path 10 and stops on the side face of the conveyor path 10. The conveyor system 1 according to the first embodiment is a linear motor with a movable magnet. The carrier 16 can be one that moves along a guide rail provided on a top surface of the conveyor path 10. The carrier 16 comprises permanent magnets forming a runner, permanent magnets for a linear scale, and a guide roller that moves along the guide rail by rotation. Fig. 1 The guide rail, the guide roller, the permanent magnets that form the runner, and the permanent magnets for the linear scale are not shown.

[0020] The direction of movement of the carriers 16 is in Fig. 1 clockwise and in Fig. 1. Counterclockwise. The direction of movement is clockwise. Fig. 1 is defined as the forward direction. The direction of movement is counterclockwise. Fig. Arrow 1 is defined as the reverse direction. An arrow 17A indicates the forward direction. An arrow 17B indicates the reverse direction.

[0021] In the Fig. In the example shown, conveyor system 1 comprises eight conveyor path units 11 and three carriers 16. The number of conveyor path units 11 included in conveyor system 1 can be arbitrarily determined. That is, the number of conveyor path units 11 that form conveyor path 10 can be arbitrarily determined. Conveyor system 1 only needs to include multiple conveyor path units 11. The number of carriers 16 that move along conveyor path 10 can also be arbitrarily determined. Conveyor system 1 only needs to include one or more carriers 16.

[0022] Conveyor system 1 is not limited to a system with a linear motor; it can also be a system with a rotary motor. Conveyor system 1 can be a conveyor belt comprising the rotary motor and a belt rotated by the rotary motor. The conveyor belt moves a workpiece placed on the belt. Conveyor system 1 can also be a roller conveyor comprising multiple rollers and the rotary motor that rotates the rollers. The roller conveyor moves a workpiece placed on the rollers.

[0023] The DC power supply 13 is connected to the conveyor path units 11 via a DC power supply bus 15. The DC power supply 13 is a power supply device or circuit that outputs a DC voltage. The DC power supply 13 provides electrical energy to the conveyor path units 11. The conveyor path units 11 share the DC power supply 13.

[0024] A positive DC bus and a negative DC bus run through the DC supply bus 15. The positive DC bus is referred to as the P-bus. The negative DC bus is referred to as the N-bus. The P-bus is connected to a positive terminal of the DC supply 13. The N-bus is connected to a negative terminal of the DC supply 13. Hereinafter, the term PN buses is used to refer to both the P-bus and the N-bus. The multiple conveyor path units 11, which form the conveyor path 10, are connected to the common PN buses.

[0025] The conveyor system 1 comprises a configuration in which the conveyor path units 11 are connected to the DC power supply 13 via a multi-connection. The form of the connection between the conveyor path units 11 and the DC power supply 13 is not limited to a multi-connection and can also be a daisy chain connection. In the Fig. In the example shown, conveyor system 1 comprises one unit of DC power supply 13, but can comprise multiple units of DC power supplies 13. That is, conveyor system 1 can comprise multiple power supply domains.

[0026] The controller 12 is connected to the conveyor path units 11 via a data communication line 14. The data communication line 14 includes a line connecting the controller 12 and conveyor path unit 11A, which is one of several conveyor path units 11, as well as lines connecting the adjacent conveyor path units 11. The conveyor system 1 comprises a configuration in which the conveyor path units 11 are connected to the controller 12 via a daisy chain connection.

[0027] The connection between the conveyor path units 11 and the controller 12 is not limited to a daisy chain connection. The connection between the conveyor path units 11 and the controller 12 can be a star connection, where the conveyor path units 11 are connected to the controller 12 via a communication node. Alternatively, the conveyor system 1 can include multiple data communication lines 14, and the conveyor path units 11 and the controller 12 can be directly connected via the data communication lines 14.

[0028] The controller 12 generates an operating command specifying a motion mode for each of the multiple carriers 16 and, based on this operating command, generates a position command for each of the carriers 16. The operating command includes information such as acceleration, deceleration, and motion speed. Based on the position command for each of the carriers 16, the controller 12 generates a coil drive command. The controller 12 outputs the coil drive command to the conveyor path units 11. The coil drive command includes a current command specifying a command value for a current flowing through each coil in the conveyor path units 11. The conveyor path units 11 each control the current flowing through each coil according to the current command included in the coil drive command. The controller 12 outputs the coil drive command to the conveyor path units 11, thereby controlling the motion of the carriers 16.

[0029] The controller 12 can be connected to a higher-level control device, such as a programmable logic controller (PLC), which is superior to the controller 12. Such a control device issues a command to the controller 12 for subsequent control. A human-machine interface (HMI) can be connected to the controller 12. An operator uses the HMI to input information. The HMI also outputs information indicating the status of the conveyor system 1. For example, the HMI displays information indicating the status of the conveyor system 1. The controller 12 can receive operating information from the carrier 16 from the higher-level control device or the HMI and generate the position command based on this operating information.The operational information is information that specifies a schedule for the movement of each of the multiple carriers 16 along the conveyor path 10. The operational information includes information about a movement start position, a stop position, a movement time, and the like.

[0030] Next, a configuration of the conveyor path unit 11 is described. Here, the linear conveyor path unit 11 is used as an example to describe its configuration. The curved conveyor path unit 11 differs from the linear conveyor path unit 11 in the arrangement of the coils. Apart from this different arrangement, the configuration of the curved conveyor path unit 11 is similar to that of the linear conveyor path unit 11.

[0031] Fig. Figure 2 is a diagram showing an exemplary configuration of the conveying path unit 11 included in the conveying system 1 according to the first embodiment. Fig. Figure 2 shows a schematic configuration of the conveyor path unit 11 and a schematic configuration of the carrier 16 on the conveyor path unit 11. The carrier 16 includes permanent magnets 40, which form the runner, and permanent magnets 41 for a linear scale.

[0032] Fig. Figure 2 shows an N-pole magnet and an S-pole magnet as permanent magnets 40 forming the runner, but the permanent magnets 40 forming the runner can comprise any number of N-pole magnets and any number of S-pole magnets. The N-pole magnet and the S-pole magnet as permanent magnets 40 are arranged alternately along an arrangement direction of several coils 20, which will be described later. The carrier 16 moves by obtaining a driving force from an interaction between an electromagnetic force generated by the coils 20, which will be described later and which are included in the conveyor path unit 11, and a magnetic field generated by the permanent magnets 40 forming the runner.

[0033] Furthermore, in Fig. 2 Four N-pole magnets and four S-pole magnets are shown as permanent magnets 41 for a linear scale. As in Fig. As shown in Figure 2, the N-pole magnets and the S-pole magnets are arranged alternately as permanent magnets 41 along the arrangement direction of the multiple coils 20 to be described later. The permanent magnets 41 for the linear scale can comprise any number of N-pole magnets and any number of S-pole magnets.

[0034] The conveyor path unit 11 comprises the several coils 20. In the in Fig. In the example shown, the conveyor path unit 11 comprises 12 coils 20. The number of coils 20 included in the conveyor path unit 11 is arbitrarily determined. In the linear conveyor path unit 11, the multiple coils 20 are arranged along a linear path. It should be noted that in the curved conveyor path unit 11, the multiple coils 20 are arranged along a curved path. Each of the coils 20 in the conveyor path unit 11 includes not only a pure inductance component but also a coil resistance.

[0035] Each of the coils 20 in the conveyor path unit 11 is connected to an inverter 21. The inverter 21 includes a switching element and supplies the power gained by switching the switching element to the coil 20. The switching element is not shown. The inverter 21 controls a current flowing through the coil 20. The inverter 21 is a single-phase full-bridge inverter circuit or a single-phase half-bridge inverter circuit. The inverter 21 can also be a three-phase inverter circuit connected to three of the coils 20.

[0036] Each of the inverters 21 in the conveyor path unit 11 is connected between a P-bus 31, which is a positive terminal of the DC power supply bus 15, and an N-bus 32, which is a negative terminal of the DC power supply bus 15. Each of the inverters 21 converts DC current from the PN buses into AC current and supplies the AC current to the coil 20. The inverter 21 uses the switching element to convert the DC current into AC current.

[0037] The coil 20 uses the power supplied by the inverter 21 to generate the electromagnetic force as a thrust to move the carrier 16. The coil 20 and the inverter 21 function as a drive unit, which is powered to generate the thrust to move the carrier 16. The conveyor path unit 11 comprises several of these drive units.

[0038] Each of the coils 20 in the conveyor path unit 11 is connected to a current sensor 22. The current sensor 22 detects an actual coil current value, which is a value of the current flowing through the coil 20. Furthermore, in the conveyor path unit 11, a capacitor 23, which is an electrolytic capacitor, is connected between the P-bus 31 and the N-bus 32. The capacitor 23 prevents abrupt voltage fluctuations in the P-buses in the conveyor path unit 11. A voltage detector 33 is connected between the P-bus 31 and the N-bus 32. The voltage detector 33 detects a bus voltage relative to the potential of the N-bus 32, which is a voltage between the P-bus 31 and the N-bus 32. The voltage detector 33 outputs the detected bus voltage to a processor 27.

[0039] Each of the inverters 21 in the conveyor unit 11 is connected to a current controller 24, which controls the inverter 21. The current controller 24 calculates a voltage value applied to the coil 20 based on a command value of the current flowing through the coil 20 and the actual coil current value detected by the current sensor 22. The current controller 24 sends a pulse-width modulation (PWM) signal, obtained by comparing the calculated voltage value with a triangle wave, to the inverter 21. The current controller 24 sends the PWM signal to the inverter 21, causing the inverter 21 to perform a switching action. As a result, the current controller 24 applies the voltage to the coil 20 to allow a current with a desired current value to flow through the coil 20.The current controller 24 can calculate the voltage value of the voltage applied to the coil 20 by performing proportional-integral-differential (PID) control of the voltage applied to the coil 20 based on a deviation between the current command value and the actual coil current value. Additionally, the current controller 24 outputs the actual coil current value, as detected by the current sensor 22, to the processor 27.

[0040] The conveyor path unit 11 comprises a linear scale 25, the processor 27, and a communication slave station 28. The linear scale 25 is a sensing unit that detects the position of the carrier 16 on the conveyor path unit 11. The linear scale 25 is installed on the conveyor path 10 when the multiple conveyor path units 11 are coupled together to form the conveyor path 10. The processor 27 is a central processing unit (CPU). The processor 27 can be an arithmetic unit, a processing unit, a microprocessor, a microcomputer, or a digital signal processor (DSP).

[0041] The linear scale 25 comprises several position sensors 26. The position sensors 26 are each sensors that detect a magnetic field, such as Hall sensors or magnetoresistive sensors. The position sensors 26 each detect a magnetic field of the permanent magnets 40 or a magnetic field of the permanent magnets 41. Here, position sensor 26 is the Hall sensor equipped with two Hall elements. The distance between the two Hall elements corresponds to half the magnetic pole pitch of the permanent magnets 41. Each of the Hall elements converts the magnetic field into an electrical signal and outputs the electrical signal. The electrical signal output by each of the Hall elements changes when the carrier 16 moves. The waveform of the electrical signal output by one of the Hall elements of the position sensor 26 is a sine wave.The waveform of the electrical signal output by the other of the Hall elements of the position sensor 26 is a cosine wave.

[0042] The electrical signals from each of the position sensors 26 of the linear scale 25 are input to the processor 27. An analog-to-digital converter (ADC) included with the processor 27 acquires the sine and cosine waves. Based on the sine and cosine wave information, the processor 27 calculates an arctangent, thereby determining the position of the carrier 16 relative to the position sensor 26. As a result, the processor 27 obtains position sensor information indicating the relative position of the carrier 16 with respect to the position sensor 26. It should be noted that in Fig. 2 the communication line between each of the position sensors 26 and the processor 27 is not shown.

[0043] Processor 27 receives the voltage value, which is the detected bus voltage, from voltage detector 33. Processor 27 detects the actual coil current value from current controller 24. Processor 27 performs a calculation, taking the actual coil current value into account, to determine whether a component of the conveyor system is in an overload state. The determination of whether a component of the conveyor system is in an overload state is described later.

[0044] The communication slave station 28 is located adjacent to the conveyor path unit 11. The data communication line 14 is connected to the communication slave station 28. In a case where the conveyor path units 11 and the controller 12 are connected by a daisy chain connection, two lines of the data communication lines 14 can be connected to the communication slave station 28. The communication slave station 28 receives the coil drive command sent by the controller 12. The communication slave station 28 sends the current command included in the coil drive command to each of the multiple current controllers 24. As a result, the conveyor path unit 11 controls the current flowing through each of the multiple coils 20 according to the coil drive command.

[0045] Furthermore, the communication slave station 28 receives the position sensor information from the processor 27. The communication slave station 28 sends the received position sensor information to the controller 12. The communication slave station 28 performs, for example, periodic communication, in which it receives the coil drive command and periodically sends the position sensor information. Instead of this periodic communication, the communication slave station 28 can receive the coil drive command and send the position sensor information aperiodically.

[0046] The conveyor path unit 11 includes a temperature sensor 34. The temperature sensor 34 measures the temperature of the conveyor path unit 11. The temperature sensor 34 outputs the measured temperature to the processor 27. The processor 27 monitors the temperature measured by the temperature sensor 34.

[0047] As described above, the conveyor path unit 11 mainly comprises the function for controlling the excitation of the coils 20 and the function for obtaining position sensor information. Each of the multiple conveyor path units 11 that form the conveyor path 10 similarly controls the excitation of the coils 20 and similarly obtains the position sensor information.

[0048] Next, the overload protection in the conveyor path unit 11 is described. In each of the multiple conveyor path units 11 included in the conveyor system 1, the processor 27 determines whether each of the multiple drive units is in an overload state and further determines whether the conveyor path unit 11 itself is in an overload state. In each of the multiple conveyor path units 11 included in the conveyor system 1, the processor 27 performs overload protection processing that reduces the temperature of the drive unit determined to be in an overload state or the temperature of the conveyor path unit 11 determined to be in an overload state.

[0049] The overload condition of the drive unit means that a component of the drive unit is overheating. That is, the overload condition of the drive unit refers to a state in which the temperature of the component exceeds the temperature at which the component can continue to operate normally. The overload condition of the conveyor path unit 11 means that the entire interior of the conveyor path unit 11 is overheating. That is, the overload condition of the conveyor path unit 11 refers to a state in which the temperature inside the conveyor path unit 11 exceeds the temperature at which each of the components contained within the conveyor path unit 11 can continue to operate normally. The components contained within the conveyor path unit 11 include the component that forms the drive unit and the component that is separate from the component that forms the drive unit.The component that differs from the component that forms the drive unit is, for example, the capacitor 23, the processor 27, or the like.

[0050] This section describes the overload protection of the drive unit. Processor 27 monitors whether one or more of the components included in the drive unit are in an overload state. That is, the drive unit comprises the components that are monitored to determine if they are in an overload state. Here, the inverter 21, as the first component included in the drive unit, and the coil 20, as the second component included in the drive unit, are the components to be monitored.

[0051] The coil 20 and the inverter 21 each exhibit an electrical resistance component. A loss occurs in the coil 20, corresponding to the current flowing through the coil 20. A loss also occurs in the inverter 21, corresponding to the current flowing through the inverter 21. In the coil 20, this loss is caused by the coil resistance.

[0052] The inverter 21 comprises, for example, a semiconductor switching element such as a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT) and a commutation diode. In the inverter 21, losses due to resistance at the time of excitation of the MOSFET or IGBT, or losses such as conduction losses in the diode, can be generated.

[0053] In the component, such as the coil 20 or the inverter 21, heat is generated due to losses, and if the component's temperature exceeds a permissible temperature, the component can deteriorate or break. Component deterioration or breakage includes, for example, a decrease in the electromagnetic force generated by the coil 20, damage due to burning out or similar occurrences in the coil 20, a stuck or broken switching element in the inverter 21, a broken diode in the inverter 21, or the like. Therefore, the conveyor path unit 11 provides overload protection for the coil 20 and the inverter 21, which constitute the components of the drive unit.

[0054] If a continuous temperature increase of the component forming the drive unit is denoted by “ΔT” [K], “ΔT” is expressed by the following formula (1). In formula (1), “R th “[K / W] represents the thermal resistance of the component in steady state. Furthermore, “P” [W] represents the loss. ΔT=Rth×P

[0055] The loss “P” is expressed by the following formula (2). In formula (2), “R” [Ω] represents the resistance of the component. Furthermore, “I” [Arms] represents the root mean square of the current flowing through the component. P=R×I2

[0056] Processor 27 receives the actual coil current value from current controller 24. Based on the actual coil current value, processor 27 calculates the root mean square (RMS) of the current flowing through the component that forms the drive unit. The current value that causes the component to reach its permissible temperature is determined as the maximum rated current. If the root mean square (RMS) of the current flowing through the component that forms the drive unit is equal to or less than the component's maximum rated current, the current can flow continuously through the component.

[0057] The thermal resistance of the component that forms the drive unit also includes the thermal resistance due to transient losses. The thermal resistance due to transient losses is referred to as transient thermal resistance. Even if a current exceeding the component's maximum rated current flows through it, the component will not fail if the current flows only for a short time and the component's temperature does not rise above its permissible temperature.

[0058] Fig. Figure 3 is a graph illustrating the thermal resistance of the component comprising the drive unit in the conveyor system 1 according to the first embodiment. Fig. Figure 3 shows the graph representing the relationship between transient thermal resistance and time. The in Fig. The vertical axis shown in section 3 represents “θ”. th “[K / W], which is the transient thermal resistance. The in Fig. The horizontal axis shown in 3 represents time [s]. The vertical axis in Fig. 3 and the horizontal axis in Fig. 3 are both logarithmic scales.

[0059] As in Fig. As shown in Figure 3, the transient thermal resistance increases over time and becomes constant after a certain period. When the transient thermal resistance becomes constant, its value corresponds to the value of "R". th “agrees, which represents the thermal resistance in the steady state.

[0060] Fig. Figure 4 is a graph representing an example of a first overload determination curve, which serves as the first criterion for the overload state in the conveying system 1 according to the first embodiment. The first overload determination curve, as the first criterion, represents a relationship between a first load determination value and time. The first load determination value is a threshold value of the current flowing through the component when the component is not in the overload state and when the component is in the overload state. The curve shown in Figure 4 represents the first overload determination curve. Fig. The vertical axis shown in Figure 4 represents time [s]. Fig. The horizontal axis shown in Figure 4 represents the squared mean of the current, which is the squared mean of the current flowing through the component. The in Fig. The horizontal axis shown in Figure 4 can also be seen as the amount of load exerted on the component.

[0061] Processor 27 uses the relationship between the first load determination value and the time period during which the current flows through the component. That is, it uses the first criterion, which is the previously determined first overload determination curve, to compare the root mean square of the current flowing through the component forming the drive unit and the time period during which the current flows through the component forming the drive unit with the first overload determination curve, thus determining whether the component is in an overload state or not. In other words, Processor 27 compares the first criterion with the root mean square of the current flowing through the component forming the drive unit and the time period during which the current flows through the component, and thus determines whether the component forming the drive unit is in an overload state or not.It should be noted that the first overload determination curve can be determined in advance as the first criterion in the processor 27, or that the first overload determination curve, which is recorded in a recording medium and determined in advance, can be read by the processor 27 and used for the operation of the processor 27.

[0062] One in Fig. Curve 51 shown in Figure 4 is an example of the first overload determination curve for coil 20. One in Fig. Curve 52, shown in Figure 4, is an example of the first overload determination curve for inverter 21. As shown by curve 51, the mean square of the current, as the first load determination value, decreases over time and becomes constant after a certain period. On curve 51, the mean square of the current "I1" when the mean square of the current becomes constant is the maximum rated current of coil 20. As shown by curve 52, the mean square of the current, as the first load determination value, decreases over time and becomes constant after a certain period. On curve 52, the mean square of the current "I2" when the mean square of the current becomes constant is the maximum rated current of inverter 21.

[0063] Points 53, 54, and 55 each represent an excitation scheme that is a combination of the time the current flows through coil 20 and inverter 21 and the root mean square (RMS) of the current flowing through coil 20 and inverter 21. In the case of the first excitation scheme, shown by point 53, the root mean square current flowing through coil 20 and inverter 21, which form the components of the drive unit, is less than the maximum rated current of coil 20 and less than the maximum rated current of inverter 21. Thus, in the case of the root mean square current of the first excitation scheme, even if the current flows continuously through coil 20 and inverter 21, neither coil 20 nor inverter 21 is in an overload state.Therefore, processor 27 determines that neither coil 20 nor inverter 21 is in an overload state under the first excitation scheme. That is, processor 27 determines that the drive unit is not in an overload state.

[0064] In the case of a second excitation scheme, shown by point 54, the root mean square (RMS) of the current flowing through the coil 20 and the inverter 21, which constitute the components of the drive unit, is greater than the maximum rated current of the coil 20 and greater than the maximum rated current of the inverter 21. However, the RMS of the current flowing through the coil 20 and the inverter 21 is less than the first load determination value shown by curve 51 and less than the first load determination value shown by curve 52. In the case of the second excitation scheme, the excitation is transient and of short duration, so neither the coil 20 nor the inverter 21 is in an overload state. Therefore, the processor 27 determines that neither the coil 20 nor the inverter 21 is in an overload state in the second excitation scheme.This means that processor 27 determines that the drive unit is not in an overload state.

[0065] In the case of a third excitation scheme, shown by point 55, the root mean square (RMS) of the current flowing through coil 20 and inverter 21, which constitute the components of the drive unit, is greater than the maximum rated current of coil 20 and less than the maximum rated current of inverter 21. The RMS of the current flowing through coil 20 and inverter 21 is greater than the first load determination value shown by curve 51. In the case of the third excitation scheme, the excitation is not transient but long-lasting, so while inverter 21 is not in an overload state, coil 20 is. Therefore, processor 27 determines that inverter 21 is not in an overload state in the third excitation scheme, but coil 20 is.Since the coil 20 is in an overload state, the processor 27 determines that the drive unit is in an overload state.

[0066] As described above, the processor 27 determines whether the drive unit is in an overload state or not based on the root mean square of the current flowing through the components and the duration of that current flow. It should be noted that in the description above, the monitoring target in the drive unit is the coil 20 and the inverter 21; however, the monitoring target can be either the coil 20 or the inverter 21. Furthermore, a component other than the coil 20 and the inverter 21 can be added as a monitoring target. The monitoring target can be any component through which a current flows. Subsequently, the processor 27 uses an overload determination curve suitable for the component of the drive unit being monitored and determines whether the drive unit is in an overload state or not.

[0067] Next, the process for determining whether the drive unit is in an overload state is described in more detail. Processor 27 receives the actual coil current value from current controller 24 and then performs first-order lag filtering on this actual coil current value. Processor 27 compares the excitation scheme—which is the combination of the actual coil current value obtained after first-order lag filtering and the time period during which the current flows through coil 20 and inverter 21—with the first overload determination curve, thus determining whether coil 20 and inverter 21 are each in an overload state. Processor 27 includes the function of determining whether coil 20 and inverter 21, which are included in each of the multiple drive units provided in the conveyor path unit 11, are in an overload state as described above.

[0068] Next, a specific example of overload protection processing is described in a case where the drive unit is detected to be in an overload state. When the processor 27 detects the drive unit where the coil 20 and / or the inverter 21 are found to be in an overload state, the processor 27 sends an alarm to the conveyor path units 11 in conveyor system 1, indicating that the drive unit is in an overload state.

[0069] The processor 27 of each of the conveyor path units 11 executes the overload protection processing when the conveyor path units 11 receive the alarm. In this example, the processor 27 of each of the conveyor path units 11 performs the overload protection processing when the conveyor path units 11 receive the alarm, which stops the excitation of the drive units by the current controllers 24. Thus, the processor 27 of each of the conveyor path units 11 performs a control action to stop all carriers 16 in the conveyor system 1. In this example, the multiple conveyor path units 11 perform the overload protection processing in a case where at least one of the multiple drive units in one of the multiple conveyor path units 11 is determined to be in an overload state, in order to stop all carriers 16 on the conveyor path 10.The overload protection processing in this case is a processing that reduces the temperature of the drive unit by setting the load of the coil 20 and the load of the inverter 21 to zero.

[0070] Each of the conveyor path units 11 can perform overload protection processing to decelerate and then stop the carriers 16. Each of the conveyor path units 11 can perform overload protection processing to activate regenerative braking by short-circuiting the coil 20. Furthermore, the processor 27 of each of the conveyor path units 11 can perform overload protection processing that reduces the amount of current flowing to each of the drive units. In this case, the processor 27 of each of the conveyor path units 11 performs a control operation that reduces the amount of current to decelerate all carriers 16 in the conveyor system 1. The overload protection processing in this case is a process that lowers the temperature of the drive unit by reducing the load on the coil 20 and the load on the inverter 21.

[0071] As described above, if at least one of the multiple drive units in one of the multiple conveyor path units 11 is determined to be in an overload state, the multiple conveyor path units 11 can perform the overload protection processing to delay all carriers 16 on the conveyor path 10. The conveyor system 1 performs the overload protection processing to stop or delay all carriers 16 on the conveyor path 10, thereby preventing a problem such as burning out due to overheating.

[0072] In the description above, overload protection processing is performed to stop or decelerate all carriers 16 on the conveyor path 10, but the overload protection processing performed by the conveyor system 1 is not limited to this. In a case where at least one of the several drive units in one of the several conveyor path units 11 is determined to be in an overload state, only the conveyor path unit 11 that includes the drive unit determined to be in an overload state can perform the overload protection processing to stop or decelerate the carrier 16. In this case, the carrier 16 on the conveyor path 10 formed by the conveyor path unit 11 that is different from the conveyor path unit 11 that includes the drive unit determined to be in an overload state will not be stopped or decelerated.If only the conveyor path unit 11, which includes the drive unit determined to be in an overload state, performs the overload protection processing to stop or delay the carrier 16, then all carriers 16 in the conveyor path unit 11, which includes the drive unit determined to be in an overload state, can be stopped or delayed, or some of the carriers 16 in the conveyor path unit 11, which includes the drive unit determined to be in an overload state, can be stopped or delayed. In this case, the processor 27 stops the excitation of each of the drive units or reduces the amount of current flowing to each of the drive units only in the conveyor path unit 11, which includes the drive unit determined to be in an overload state. Again, in this case, the conveyor system 1 can avoid a problem such as burning out due to overheating.

[0073] Alternatively, if at least one of the several drive units in one of the several conveyor path units 11 is determined to be in an overload state, the implemented overload protection process can stop the excitation only of the drive unit that is determined to be in an overload state. In this case as well, the conveyor system 1 can avoid the problem of burnout due to overheating.

[0074] Next, we describe how it is determined whether the conveyor path unit 11 is in an overload state, and we give a concrete example of an overload protection function in a case where the conveyor path unit 11 is found to be in an overload state. In each of the multiple conveyor path units 11 included in the conveyor system 1, the processor 27 determines whether the conveyor path unit 11 is in an overload state or not. In each of the multiple conveyor path units 11, the processor 27 performs the overload protection processing, which lowers the temperature of the conveyor path unit 11 that is determined to be in an overload state.

[0075] In addition to the coil 20 and the inverter 21, which constitute the components of the drive unit, electronic components such as the capacitor 23 and the processor 27 are provided in a housing of the conveyor path unit 11. Generally, the permissible temperature of the capacitor 23 and the permissible temperature of the processor 27 are lower than the permissible temperature of the coil 20 or the permissible temperature of the inverter 21.

[0076] Here, the loss in a case where the current flowing through all coils 20 included in the conveyor path unit 11 is equal to the maximum rated current of the coil 20 is defined as the worst loss of the conveyor path unit 11. In the case where 12 coils 20 are provided in the conveyor path unit 11, as in Fig. As shown in Figure 2, the worst loss of conveyance pathway unit 11 is expressed by the following formula (3). In formula (3) “R coil“[Ω] represents a resistance value of coil 20. Furthermore, “R” stands for inv “[Ω] represents a resistance of the energized inverter 21. In addition, “I crated “[Arms] for the maximum rated current of the coil 20. Worst loss of conveying path unit = 12×(Rcoil+Rinv)×Icrated2

[0077] When heat is generated by the resistance of the coil 20 and the resistance of the inverter 21, the heat is distributed within the conveyor path unit 11, transmitted through a substrate or the like within the conveyor path unit 11, or the like, causing the temperature of the entire conveyor path unit 11 to rise. As the temperature of the entire conveyor path unit 11 rises, the temperature of the coil 20 or the inverter 21 may not exceed the permissible temperature, but the temperature of the capacitor 23 or the processor 27 may exceed the permissible temperature.

[0078] As in Fig. As shown in Figure 2, it is assumed that the length of the conveyor path unit 11 is longer than the length of the carrier 16. In this case, it can be said that it is rare for the current value of all coils 20 in the conveyor path unit 11 to correspond to the maximum rated current value of the coil 20. It should be noted that the length is defined as the length in the direction of movement of the carrier 16.

[0079] Fig. Figure 5 is a first diagram to illustrate the worst loss of the conveying path unit 11 in the conveying system 1 according to the first embodiment. Fig. Figure 5 shows an example of a condition in which the current value of the current flowing through all coils 20 included in the conveyor path unit 11 is the maximum rated current value of the coil 20. Fig. 5 denotes “L” [mm] as a distance between adjacent beams 16. The in Fig. Example 5 assumes that “L” [mm] corresponds almost exactly to the length of the carrier 16 in the direction of movement of the carrier 16. It is assumed here that there are four or more carriers 16 in the conveyor system 1. Fig. Figure 5 shows a state in which four of the carriers 16A, 16B, 16C and 16D are arranged without a gap on the conveyor path unit 11. An arrow 42 indicates the direction of movement of the carrier 16.

[0080] In conveyor system 1, if the rated current flows only to the coil 20 in the area where the carrier 16 is located, the carrier 16 can be moved without a reduction in the rated thrust force. However, if the carriers 16 are located on all coils 20 of the conveyor unit 11 and are moved at the rated thrust force and speed, the loss of the conveyor unit 11 is greatest. In conveyor system 1, which is a linear motor with a moving magnet, it can be assumed that the multiple carriers 16 within the conveyor system 1 will rarely operate in such a configuration. Therefore, it can be said that the current value of all coils 20 in the conveyor unit 11 rarely corresponds to the maximum rated current value of the coil 20.

[0081] Fig. Figure 6 is a second diagram to illustrate the worst loss of the conveying path unit 11 in the conveying system 1 according to the first embodiment. Fig. Figure 6 shows a waveform of the current flowing through one of the coils 20 in a case where the multiple carriers 16 pass the conveyor path unit 11 without a time interval. That is, the in Fig. The waveform shown in Figure 6 is the waveform of the current flowing through one of the coils 20 when the loss of the conveyor path unit 11 is greatest. The vertical axis in Fig. 6 represents the current [A] flowing through coil 20. The horizontal axis in Fig. 6 represents time [s].

[0082] Here it is assumed that the four carriers 16A, 16B, 16C and 16D pass sequentially over one of the coils 20. Fig. Time t1 is the time at which the center of carrier 16A is directly above coil 20. Time t2 is the time at which the boundary between carrier 16A and carrier 16B is directly above coil 20. Time t3 is the time at which the center of carrier 16B is directly above coil 20. Time t4 is the time at which the boundary between carrier 16B and carrier 16C is directly above coil 20. Time t5 is the time at which the center of carrier 16C is directly above coil 20. Time t6 is the time at which the boundary between carrier 16C and carrier 16D is directly above coil 20. Time t7 is the time at which the center of carrier 16D is directly above coil 20.

[0083] To accommodate the carriers, 16 pass one after the other without interruption, as in Fig. As shown in Figure 6, when the nominal thrust force is constantly applied, the current is continuously passed through coil 20 with a waveform that closely approximates a sine wave. The currents flowing through the multiple coils 20 in the conveyor system 1 exhibit the same waveform and phases, which are varied accordingly. When the nominal thrust force is constantly applied to the carriers 16 passing successively without interruption, the square mean of the current flowing through one of the coils 20 is called "I". cratedmax " designated.

[0084] Although it is rare for the failure of the conveyor path unit 11 to be the worst loss, the overload protection device's capacity is excessive for the capacity suitable for operating the conveyor system 1 if the conveyor system 1 is equipped with the overload protection function designed for the event that the failure of the conveyor path unit 11 is the worst loss. In a case where an overload protection configuration, such as a cooling structure, is provided in the conveyor path unit 11, the overload protection's capacity is excessive, resulting in an unnecessarily large conveyor system configuration and unnecessarily high manufacturing costs.

[0085] In the first embodiment, a condition in which the load is less than that resulting from a constant thrust force on the successive carriers 16 without a time interval is defined as the overload condition of the conveyor path unit 11. In other words, the loss that is less than the worst loss of the conveyor path unit 11 is defined as a maximum nominal loss, which corresponds to the loss of the conveyor path unit 11 when the conveyor path unit 11 is in the overload condition. The processor 27 performs the overload protection processing when the loss of the conveyor path unit 11 reaches the maximum nominal loss. This allows the conveyor system 1 to implement overload protection suitable for its operation. Implementing overload protection suitable for the operation of the conveyor system 1 prevents unnecessary enlargement of the conveyor system 1's configuration and an unnecessary increase in its manufacturing costs.

[0086] A power loss corresponding to the loss of conveying path unit 11 is expressed by the following formula (4). In formula (4) “P load “[W] for the loss of performance of the conveying pathway unit 11. Furthermore, “I coil “[Arms] for the square mean of the current flowing through coil 20. The sum on the right-hand side of formula (4) is a sum for all coils 20 in the conveyor path unit 11. The processor 27 calculates the loss of the conveyor path unit 11 using formula (4). Pload=∑(Icoil2)

[0087] In a case where the loss of the conveying path unit 11 is the worst loss, the maximum nominal loss P loadrated The conveying path unit 11 is expressed by the following formula (5). The sum on the right-hand side of formula (5) is a sum for all coils 20 in the conveying path unit 11. Ploadrated=∑(Icratedmax2)

[0088] However, as described above, in conveyor system 1 it is rare that the square mean of the current of all coils 20 in the conveyor path unit 11 “I cratedmax “ is. That is, it is rare that the loss of conveying path unit 11 is the worst loss expressed by formula (5).

[0089] Fig. Figure 7 is a graph representing an example of a second overload determination curve, which serves as a second criterion for the overload state in the conveying system 1 according to the first embodiment. The second overload determination curve, representing the second criterion, represents a relationship between a second load determination value and time. The second load determination value is a threshold for the failure of the conveying path unit 11 when the conveying path unit 11 is not in the overload state and when the conveying path unit 11 is in the overload state. The in Fig. The vertical axis shown in Figure 7 represents time [s]. Fig. The horizontal axis shown in 7 represents the loss of the conveying path unit 11. The in Fig. The horizontal axis shown in Figure 7 can also be described as the magnitude of the load exerted on the conveyor path unit 11. Here, exerting the load on the conveyor path unit 11 means that a current flows through at least one of the several coils 20 in the conveyor path unit 11.

[0090] The processor 27 calculates the root mean square of the current flowing through the coil 20 based on the actual coil current value detected by the current controller 24. The processor 27 uses the relationship between the second load determination value and the time period during which the load is applied to the conveyor path unit 11, i.e., the second criterion, which is the predefined second overload determination curve, to compare the loss of the conveyor path unit 11, obtained on the basis of the root mean square of the current flowing through each of the multiple drive units and the time period during which the load is applied to the conveyor path unit 11, with the second overload determination curve, thereby determining whether the conveyor path unit 11 is in an overload state or not.This means that the processor 27 compares the second criterion with the loss of the conveyor path unit 11 and the time period during which the load is applied to the conveyor path unit 11, and thereby determines whether the conveyor path unit 11 is in an overload state or not. It should be noted that the second overload determination curve can be predefined as the second criterion in the processor 27, or that the second overload determination curve recorded and predefined on a recording medium can be read by the processor 27 and used for its operation.

[0091] One in Fig. Curve 56, shown in Figure 7, is an example of the second overload determination curve. As shown by curve 56, the loss value, which is the second load determination value, decreases over time and becomes constant after a certain period. That is, in the second overload determination curve, the second load determination value converges to a constant value over time. In curve 56, "P1", the loss value when the loss value becomes constant, is the value of the maximum rated loss of the conveying path unit 11. In other words, the loss of the conveying path unit 11 is the maximum rated loss when the second load determination value is a constant value.

[0092] Points 57, 58, and 59 each represent a loss scheme, which is a combination of the duration for which the load is applied to conveyor path unit 11 and the loss of conveyor path unit 11. In the case of a first loss scheme, shown by point 57, the loss of conveyor path unit 11 is less than the maximum rated loss. Thus, even if a state with the loss of the first loss scheme persists, conveyor path unit 11 is not in an overload state. Therefore, processor 27 determines that conveyor path unit 11 is not in an overload state for the first loss scheme.

[0093] In the case of a second loss scheme, shown by point 58, the loss of the conveyor path unit 11 is greater than the maximum rated loss. However, the loss of the conveyor path unit 11 in the second loss scheme is less than a second load determination value, shown by curve 56. In the case of the second loss scheme, the load is temporarily applied to the conveyor path unit 11 for a short time, so that the conveyor path unit 11 is not in an overload state. Therefore, the processor 27 determines that the conveyor path unit 11 is not in an overload state for the second loss scheme.

[0094] In the case of a third loss scheme, shown by point 59, the loss of the conveyor path unit 11 is greater than the maximum rated loss. Furthermore, the loss of the conveyor path unit 11 in the third loss scheme is greater than the second load determination value, shown by curve 56. In the case of the third loss scheme, the load is not applied to the conveyor path unit 11 temporarily, but over a long period of time, so that the conveyor path unit 11 is in an overload state. Therefore, the processor 27 determines that the conveyor path unit 11 is in an overload state in the third loss scheme.

[0095] As described above, the processor 27 determines whether the conveyor path unit 11 is in an overload state or not, based on the loss of the conveyor path unit 11 and the time period during which the load is applied to the conveyor path unit 11.

[0096] Here, an example of setting the maximum nominal loss of the conveying path unit 11 is described. Fig. Figure 8 is a first diagram to illustrate the maximum nominal loss of the conveying path unit 11 in the conveying system 1 according to the first embodiment. Fig. Figure 8 shows an example of a condition in which the loss of the conveyor path unit 11 represents the maximum nominal loss. In the diagram, “L” [mm] represents the distance between the supports 16 in the case where the supports 16 are arranged side by side without a gap, as in Fig. 5 shown. In Fig. 8 The distance between the adjacent supports is 16 2L [mm]. Fig. Figure 8 shows a state in which two of the carriers 16A and 16B are located at a distance of 2L [mm] on the conveyor path unit 11.

[0097] In the example described here, the loss of the conveying path unit 11 in a case where the multiple carriers 16 are arranged at intervals corresponding to the length of a unit of the carrier 16 and are kept in motion at the conveying path unit 11 with the nominal thrust force and the nominal speed is referred to as the maximum nominal loss P loadrated the conveying path unit 11 is determined. In this case, the maximum nominal loss of the conveying path unit 11 is a loss that is smaller than the worst loss of the conveying path unit 11.

[0098] In the case where the carriers 16 are kept in motion on the conveyor path unit 11 with the rated thrust and rated speed, it is assumed that the distance between the carriers 16 is rarely less than the length of a single unit of carrier 16. If the maximum rated loss is determined to be the loss in the operating scheme in which the multiple carriers 16 are arranged at intervals corresponding to the length of a single unit of carrier 16 and are kept in motion on the conveyor path unit 11 with the rated torque and rated speed, operation can continue without problems for many operating schemes in which the conveyor system 1 can be operated. Furthermore, the conveyor system 1 can implement suitable overload protection for the conveyor path unit 11 through the overload protection function, which has the appropriate performance for the operation of the conveyor system 1.

[0099] Fig. Figure 9 is a second diagram to illustrate the maximum nominal loss of the conveying path unit 11 in the conveying system 1 according to the first embodiment. Fig. Figure 9 shows a waveform of a current flowing through one of the coils 20 when the multiple carriers 16 are spaced at intervals corresponding to the length of one unit of the carrier 16 and are held in motion at the conveyor path unit 11 with the rated thrust and rated speed. That is, the in Fig. The waveform shown in Figure 9 is the waveform of the current flowing through one of the coils 20 when the loss of the conveyor path unit 11 is the maximum rated loss. The in Fig. The vertical axis shown in 9 represents the current [A] flowing through coil 20. The in Fig. The horizontal axis shown in 9 represents time [s].

[0100] Here it is assumed that the two carriers 16A and 16B pass over one of the coils 20 sequentially at a distance of 2L [mm]. Fig. Time 9 is "t11", the time at which the center of carrier 16A is directly above coil 20. Time t12 is the time at which the center of carrier 16B is directly above coil 20.

[0101] In Fig. 9 is “I crated1 “The square mean of the current flowing through one of the coils 20 when the loss of the conveying path unit 11 represents the maximum rated loss. As referred to in Fig. As described in 6, “I cratedmax “The square mean of the current flowing through one of the coils 20 when the loss of the conveyor path unit 11 is the worst loss. Here is “I crated1 “ smaller than “I” cratedmax “.

[0102] The maximum nominal loss P loadrated The conveying path unit 11 is expressed by the following formula (6). The sum on the right-hand side of formula (6) is a sum for all coils 20 in the conveying path unit 11. Ploadrated=∑(Icrated12)

[0103] With I crated1 cratedmax and formula (6) results in the following formula (7). Ploadrated<∑(Icratedmax2)

[0104] Formula (7) expresses that the maximum nominal loss P loadrated The loss of the conveying path unit 11 is less than the loss of the conveying path unit 11 when the value of the current flowing through each of the several coils 20 in the conveying path unit 11 corresponds to the maximum rated current value of the coil 20. In each of the conveying path units 11 of the conveying system 1, the conveying system 1 can, when the maximum rated loss P loadrated The conveying path unit 11 fulfills formula (7), can continue to be operated without problems for many operating schemes in which the conveying system 1 can be operated, and also implement a suitable overload protection function for the conveying path unit 11.

[0105] ​It should be noted that in the above description, the maximum nominal loss is defined as the loss in the case where the distance between the multiple supports 16 corresponds to the length of one unit of the support 16, but the present disclosure is not limited to this. The maximum nominal loss only needs to be less than the worst loss and can be set arbitrarily. For example, the maximum nominal loss could be a loss in a case where the distance between the multiple supports 16 corresponds to a distance equal to half the length of the support 16.

[0106] The value of the maximum rated loss can be the same for several conveying path units 11 or it can be different for each of the conveying path units 11. For example, the value of the maximum rated loss of each of the conveying path units 11 can be set based on the size of the conveying path unit 11's housing, the type of electronic components used in the conveying path unit 11, or the like. Alternatively, the linear conveying path unit 11 and the curved conveying path unit 11 can have different values ​​for the maximum rated loss.

[0107] In conveyor system 1, the second load determination value on the second overload determination curve can be different for each of the conveyor path units 11. That is, for the multiple conveyor path units 11, the second load determination value can be set differently for each of the conveyor path units 11. In this case, conveyor system 1 can set the second load determination value according to the configuration of the conveyor path unit 11. Considering the configuration of the conveyor path unit 11, conveyor system 1 can determine whether the conveyor path unit 11 is in an overload state or not.

[0108] Next, a concrete example of overload protection processing is described in a case where conveyor path unit 11 is detected to be in an overload state. In the case where conveyor path unit 11 is detected to be in an overload state, processor 27 sends an alarm indicating that conveyor path unit 11 is in an overload state to each of the conveyor path units 11 in conveyor system 1.

[0109] The processor 27 of each of the conveyor path units 11 executes the overload protection processing when it receives the alarm. In this example, after receiving the alarm, the processor 27 of each of the conveyor path units 11 executes the overload protection processing, which stops the excitation of the drive units by the current controllers 24. Alternatively, after receiving the alarm, the processor 27 of each of the conveyor path units 11 executes the overload protection processing, which reduces the amount of current flowing to each of the drive units. Thus, the processor 27 of each of the conveyor path units 11 executes a control to stop or delay all carriers 16 in the conveyor system 1. In this example, if one of the multiple conveyor path units 11 is determined to be in an overload state, the multiple conveyor path units 11 execute the overload protection processing to stop or delay all carriers 16 on the conveyor path 10.

[0110] As described above, each of the conveyor path units 11 performs overload protection processing, which lowers the temperature of the conveyor path unit 11 by setting the load of the conveyor path unit 11 to zero or by reducing the load of the conveyor path unit 11. The conveyor system 1 performs overload protection processing to stop or decelerate all carriers 16 on the conveyor path 10, thereby preventing problems such as burnout due to overheating. It should be noted that each of the conveyor path units 11 can decelerate and then stop the carriers 16, as in the case where the drive unit is detected to be in an overload state. Each of the conveyor path units 11 can perform overload protection processing to activate a regenerative brake by short-circuiting the coil 20.

[0111] In the description above, overload protection processing is performed to stop or delay all carriers 16 on conveyor path 10, but the overload protection processing performed by conveyor system 1 is not limited to this. If one of the multiple conveyor path units 11 is determined to be in an overload state, only the conveyor path unit 11 that is determined to be in an overload state may perform the overload protection processing to stop or delay the carrier 16. In this case, the carrier 16 on the conveyor path 10 formed by the conveyor path unit 11 that is not the conveyor path unit 11 determined to be in an overload state will not be stopped or delayed.If only the conveyor unit 11, which is determined to be in an overload state, performs the overload protection processing to stop or delay the carrier 16, then all carriers 16 in the conveyor unit 11, which is determined to be in an overload state, can be stopped or delayed, or some of the carriers 16 in the conveyor unit 11, which is determined to be in an overload state, can be stopped or delayed. In this case as well, the conveyor system 1 can avoid a problem such as burning out due to overheating.

[0112] In the above description, the processor 27 detects the actual coil current value detected by the current sensor 22 and determines, based on the root mean square calculated from the actual coil current value, whether the conveyor path unit 11 is in an overload state. That is, the processor 27 determines whether the conveyor path unit 11 is in an overload state or not based on the root mean square of the current flowing through each of the multiple drive units. In this case, the processor 27 estimates the load of the conveyor path unit 11 based on the detected current flowing through each of the multiple drive units. The processor 27 can also estimate the load of the conveyor path unit 11 from a detected temperature of the conveyor path unit 11. That is, the processor 27 can determine whether the conveyor path unit 11 is in an overload state or not based on the temperature detected by the temperature sensor 34.That is, if the load of the conveying path unit 11 is estimated based on the detected temperature of the conveying path unit 11, instead of the sum of the square means of the currents flowing through all coils 20 in the conveying path unit 11, which are used to calculate the loss of the conveying path unit 11, the temperature detected by the temperature sensor 34 is used to calculate the loss P. load the conveying path unit 11 and the maximum nominal loss P loadrated The conveying path unit 11 is calculated in such a way that the second overload determination curve can be determined in advance as the second criterion. In this case, too, the conveying system 1 can avoid a problem such as burning out due to overheating.

[0113] In the description above, the processor 27 performs overload protection processing that stops the excitation of the drive unit or reduces the amount of current flowing through the drive unit, but the overload protection processing is not limited to this. The processor 27 can perform overload protection processing that reduces the switching frequency of the inverter 21. The conveyor path unit 11 can include a cooling structure that cools the interior of the conveyor path unit 11. The cooling structure is, for example, a fan. The processor 27 can perform overload protection processing that causes the cooling structure to be activated. Also, when these overload protection processes are executed, the conveyor path unit 11 can reduce the temperature of the drive unit, which is determined to be in an overload state, or the temperature of the conveyor path unit 11 itself, which is determined to be in an overload state.

[0114] According to the first embodiment, the processor 27 in the conveyor system 1 determines whether each of the multiple drive units is in an overload state and also determines whether the conveyor path unit 11 is in an overload state. In each of the multiple conveyor path units 11, the processor 27 performs the overload protection processing, which reduces the temperature of the drive unit determined to be in an overload state or the temperature of the conveyor path unit 11 determined to be in an overload state.Conveyor system 1 performs the determination at the drive unit and the determination at the conveyor path unit 11 separately, such that the maximum load, which is the maximum permissible load, is not reduced for each of the drive units, and the maximum permissible load for the conveyor path unit 11 as a whole can be reduced compared to a case in which the maximum load is applied to all drive units in the conveyor path unit 11. Conveyor system 1 does not reduce the maximum load for each of the drive units, thus allowing the carrier 16 to be moved without a reduction in the nominal thrust force. Conveyor system 1 reduces the maximum permissible load for the conveyor path unit 11 as a whole, thereby implementing overload protection suitable for the operation of conveyor system 1. Second embodiment.

[0115] In conveyor system 1, the conveyor path units 11 are arranged side by side. If, for example, a first conveyor path unit, which is one of two adjacent conveyor path units 11, experiences a temperature increase, the heat from the first conveyor path unit can be transferred to a second conveyor path unit, which is the other of the conveyor path units 11, causing a temperature increase in the second conveyor path unit. Even if the drive status of the second conveyor path unit indicates that it is not in an overload state, the second conveyor path unit can still overheat due to heat conduction from the first conveyor path unit. In this case, it is difficult to implement an appropriate overload protection measure for the second conveyor path unit.

[0116] A second embodiment describes a first example of overload protection to prevent the conveying path unit 11 from overheating due to heat transfer from one of the adjacent conveying path units 11 to another. The conveying system 1 according to the second embodiment comprises a configuration similar to that of the conveying system 1 according to the first embodiment. In the second embodiment, components identical to those of the first embodiment are designated with the same reference numerals as in the first embodiment, and the main processes described differ from those of the first embodiment.

[0117] In the second embodiment, the processor 27 determines for each of the multiple conveyor path units 11 whether the conveyor path unit 11 is in a high load state. The high load state is a state in which the load is lower than in the overload state and a state in which the overload state is expected to be reached. In a case where one of the multiple conveyor path units 11 is determined to be in a high load state, the processor 27 performs a correction for a second conveyor path unit, which is the conveyor path unit 11 that is adjacent to a first conveyor path unit determined to be in a high load state, to set the second load determination value to a preset value in the relationship shown by the second overload determination curve, which was predefined as the second criterion.The processor 27 of the second conveyor path unit determines, based on the second criterion used to make the correction to set the second load determination value smaller than the preset value, whether the second conveyor path unit is in an overload state.

[0118] The power loss corresponding to the loss of the conveyor path unit 11 is expressed by the formula (4) above. The processor 27 calculates the loss of the conveyor path unit 11 using formula (4).

[0119] In conveyor path unit 11, a loss value is predefined as a threshold for determining whether conveyor path unit 11 is in a high-load state. Here, the loss value serving as the threshold is referred to as the high-load determination value. Processor 27 compares the value of "P load “, which is the loss calculated by formula (4), with “P loadh “, which is the high-load determination value.

[0120] If P load >P loadh If the condition is met, processor 27 determines that conveyor unit 11 is in a high load state. When conveyor unit 11 is determined to be in a high load state, processor 27 sends an alarm to controller 12 indicating that conveyor unit 11 is in a high load state. The first conveyor unit, which is conveyor unit 11, to be determined to be in a high load state sends the alarm to controller 12 to inform controller 12 that it is in a high load state.

[0121] After receiving the alarm from the first conveyor unit, the controller 12 sends an alarm to the second conveyor unit indicating that the first conveyor unit is under high load. For example, if conveyor unit 11A is in the Fig. In the conveying system shown in 1, the first conveying path unit is , and the conveying path unit 11B and the conveying path unit 11H are the second conveying path units.

[0122] Upon receiving the alarm from the controller 12, the processor 27 of the second conveyor path unit corrects the value of the maximum nominal loss P. loadrated The processor 27 of the second conveyor unit 11 corrects the second load determination value on the second overload determination curve to a value that is less than a preset value. As just described, the processor 27 of the second conveyor unit receives the message from the controller 12 that the first conveyor unit is in a high load state and then corrects the second criterion shown by the second overload determination curve.

[0123] The processor 27 of the second conveyor unit determines, based on the corrected second overload determination curve as a second criterion, whether the second conveyor unit is in an overload state or not. If heat conduction from the first conveyor unit leads to an increase in the temperature of the second conveyor unit, the conveyor system 1 can perform the overload protection processing of the second conveyor unit accordingly.

[0124] According to the second embodiment, when the first conveyor path unit is under high load, the second conveying path unit in the conveying system 1 performs a correction by setting the second load determination value lower than the preset value on the second overload determination curve. This prevents the conveying path unit 11 from overheating due to heat transfer from one of the adjacent conveyor path units 11 to another. Third embodiment.

[0125] A third embodiment describes a second example of overload protection to prevent the conveying path unit 11 from overheating due to heat transfer from one of the adjacent conveying path units 11 to another. The conveying system 1 according to the third embodiment comprises a configuration similar to that of the conveying system 1 according to the first embodiment. In the third embodiment, components identical to those in the first or second embodiment are designated with the same reference numerals as those in the first or second embodiment, and the main processes described differ from those in the first or second embodiment.

[0126] In the second embodiment, the processor 27 determines whether each of the conveyor path units 11 is in a high load state. In the third embodiment, the controller 12 determines whether each of the multiple conveyor path units 11 is in a high load state.

[0127] The power loss, which is the loss of the conveyor path unit 11, is expressed by the formula (4) above. The processor 27 of each of the conveyor path units 11 calculates the loss of the conveyor path unit 11 using formula (4). The processor 27 sends the value of the loss P calculated by formula (4). load to control 12.

[0128] In control 12, the value P loadh To determine whether the conveyor path unit 11 is under high load or not, the controller 12 compares the value of the loss P for each of the multiple conveyor path units 11. load, which is calculated by formula (4), with “P loadh “The control unit 12 thus determines whether each of the several conveyor path units 11 is in a high load state or not.”

[0129] If P load >P loadh In one of the conveying path units 11, the control unit 12 determines that the conveying path unit 11, in which P load >P loadh The controller 12 sends an alarm indicating that a first conveyor path unit is in a high-load state to a second conveyor path unit adjacent to the first conveyor path unit identified as being in a high-load state. The controller 12 sends the alarm to the second conveyor path unit to inform it that the first conveyor path unit is in a high-load state.

[0130] After receiving the alarm from the controller 12, the processor 27 of the second conveyor path unit corrects the value of the maximum nominal loss P. loadrated The processor 27 of the second conveyor unit 11 corrects the second load determination value on the second overload determination curve to a value that is less than a preset value. As just described, the processor 27 of the second conveyor unit receives the message from the controller 12 that the first conveyor unit is in a high load state and then corrects the second criterion shown by the second overload determination curve.

[0131] The processor 27 of the second conveyor unit determines, as a second criterion, whether the second conveyor unit is in an overload state, based on the corrected second overload determination curve. If the second conveyor unit experiences a temperature increase due to heat conduction from the first conveyor unit and is in an overload state, the second conveyor unit can perform the overload protection processing.

[0132] In the description above, the processor 27 of the second conveyor path unit corrects the second load determination value to a value that is less than the preset value. In the third embodiment, the controller 12 can correct the second load determination value to a value that is less than the preset value. In this case, the controller 12 maintains the second criterion, shown by the second overload determination curve, for each of the multiple conveyor path units 11. For the second conveyor path unit adjacent to the first conveyor path unit, which is determined to be in a high load state, the controller 12 corrects the second criterion shown by the second overload determination curve. The controller 12 sends information indicating the corrected second criterion to the second conveyor path unit.

[0133] The processor 27 of the second conveyor unit receives the information sent by the controller 12 and, based on the second overload determination curve, which represents the corrected second criterion, determines whether the second conveyor unit is in an overload state. If heat conduction from the first conveyor unit leads to a temperature increase in the second conveyor unit, the conveyor system 1 can thus appropriately perform the overload protection processing of the second conveyor unit.

[0134] Control 12 can change the value of "P loadrated “ the second funding pathway unit according to the value of “P” load “Set the first conveyor path unit that is determined to be in a high load state. For example, if the load factor P load / P loadh Since the first conveying path unit has a value of 0.9, the controller 12 multiplies the value of the maximum nominal loss P. loadratedthe second support path unit with 0.9, to determine the value “P loadrated “to set the second conveyance path unit.” In this procedure, the value to be set is “P”. loadrated “The second conveyor path unit is multiplied by the load factor of the first conveyor path unit, but the controller 12 can set the value “P loadrated “ the second conveyance pathway unit by each procedure according to the value “P” load “Set the first conveying path unit. A program for setting the value “P loadrated “The second conveying path unit is determined in advance in control 12.

[0135] According to the third embodiment, when the first conveyor path unit is under high load, the second conveying path unit in the conveying system 1 performs a correction by setting the second load determination value lower than the preset value on the second overload determination curve. This prevents the conveying path unit 11 from overheating due to heat transfer from one of the adjacent conveyor path units 11 to the other. Fourth embodiment.

[0136] In the conveyor system 1 according to the first to third embodiments, the controller 12 generates an operating command that specifies a motion mode for each of the multiple carriers 16 and, based on the operating command, generates a position command for each of the carriers 16. The operating command includes information relating to the motion of the carrier 16, such as acceleration, deceleration, and motion speed. A fourth embodiment describes an example of applying machine learning to the generation of the operating command.

[0137] For example, it is assumed that the recorded operational information indicates that carrier 16 will reach a target position three meters ahead of its current position two seconds after a certain time. In this case, several operating command schemes are possible for moving carrier 16. One possible scheme is one in which carrier 16 is moved from a starting point to an endpoint for two seconds using trapezoidal acceleration / deceleration. Another scheme is one in which carrier 16 moves from the starting point with trapezoidal acceleration / deceleration for one second and is stopped in the last second; another scheme is one in which carrier 16 is stopped from the starting point for one second and moves with trapezoidal acceleration / deceleration in the last second; or something similar.For the recorded operational information, an infinite number of schemas are possible as schemas of the operating command.

[0138] In the conveying system 1, the highest power consumption value among the multiple conveying path units 11 is preferably as low as possible. In the following description, the highest power consumption value among the multiple conveying path units 11 is referred to as the maximum power value. In the fourth embodiment, the operating instruction that reduces the maximum power value is inferred from the infinite number of possible operating instruction schemes using machine learning.

[0139] Fig. Figure 10 is a diagram showing an exemplary configuration of a controller 60 included in the conveyor system 1 according to the fourth embodiment. The controller 60 includes a learning device 61, an operating command generation means 62, a position command generation means 63, and a coil drive command generation means 64.

[0140] The operating command generator 62 receives operating information 65. Based on the operating information 65, the operating command generator 62 generates an operating command 67. The operating command 67 generated by the operating command generator 62 is entered into the position command generator 63. Based on the operating command 67, the position command generator 63 generates a position command 68. The position command 68 generated by the position command generator 63 is entered into the coil drive command generator 64.

[0141] The coil drive command generator 64 generates a coil drive command 69 based on the position command 68. The controller 60 sends the coil drive command 69 generated by the coil drive command generator 64 to the conveyor path units 11. The controller 60 sends the coil drive command 69 to the conveyor path units 11 and thereby controls the movement of the carriers 16.

[0142] The learning device 61 receives the operating information 65 and the operating command 67. The learning device 61 learns a relationship between the operating information 65 and the operating command 67 that reduces the maximum power value. The learning device 61 outputs a trained model 66, which is a result of the learning process. The operating command generator 62 receives the trained model 66 from the learning device 61. The operating command generator 62 inputs the operating information 65 into the trained model 66 to infer the operating command 67 that reduces the maximum power value. The operating command generator 62 generates the operating command 67 through this inference.

[0143] Fig. Figure 11 is a diagram showing an exemplary configuration of the learning device 61, which is included in the controller 60 according to the fourth embodiment. The learning device 61 comprises a data acquisition unit 71, a model generation unit 72, and a storage unit 75 for trained models.

[0144] The data acquisition unit 71 acquires training data 76 and creates a data set summarizing the training data 76. The training data 76 includes the operating information 65 and the operating command 67. That is, the data acquisition unit 71 receives the training data 76, which includes the operating information 65 and the operating command 67. The training data 76 is then input into the model generation unit 72.

[0145] The model generation unit 72 generates the trained model 66 using the training data 76. The model generation unit 72 generates the trained model 66, which is used to infer the operating instruction 67 from the operating information 65, based on the training data 76. The trained model storage unit 75 stores the trained model 66.

[0146] A learning algorithm used by Model Generation Unit 72 can be a well-known algorithm, such as supervised learning, unsupervised learning, or reinforcement learning. As an example, a case is described in which reinforcement learning is used as the learning algorithm employed by Model Generation Unit 72. In reinforcement learning, a subject, as an actor operating within a given environment, observes a current state and determines an action to be taken. By choosing an action, the actor receives a reward from the environment and, through a series of actions, learns a strategy that maximizes the reward. Representative methods of reinforcement learning include Q-learning, TD-learning, and the like.

[0147] In the case of Q-learning, for example, an action value table, which is a typical update expression of an action value function Q(s, a), is expressed by the following formula (8). The action value function Q(s, a) represents an action value "Q", which is the value of an action that selects an action "a" from an environment "s". Formula 1: Q(st,at)←Q(st,at)+α(rt+1+γmaxaQ(st+1,at)−Q(st,at)

[0148] In formula (8), “st” represents an environment at time “t”. An action at time “t” is represented by “at”. The action “at” changes the environment to “s”. t+1 “A reward achieved through a change in the environment is represented by “r” t+1 “ shown. A discount factor is shown by “γ”. The discount factor “γ” satisfies 0 < γ ≤ 1. A learning rate is shown by “α”. The learning rate “α” satisfies 0 < α ≤ 1. The operational information 65 corresponds to the environment “s t". Operating command 67 corresponds to action "a t “.

[0149] The update expression, as expressed by formula (8), increases the action value “Q” if the action value of action “a”, which is the best action at time “t+1”, is higher than the action value “Q” of action “a” performed at time “t”, or decreases the action value “Q” in the opposite case. In other words, the action value function Q(s, a) is updated so that the action value “Q” of action “a” at time “t” approaches the best action value at time “t+1”. As a result, the best action value in a given environment will propagate sequentially to action values ​​in previous environments.

[0150] The model generation unit 72 comprises a reward calculation unit 73 and a function update unit 74. The reward calculation unit 73 calculates a reward based on the data set. The function update unit 74 updates a function for determining the operating command 67 according to the reward calculated by the reward calculation unit 73.

[0151] Specifically, the reward calculation unit 73 calculates a reward "r" based on the maximum performance value. For example, reward calculation unit 73 increases the reward "r" when the maximum performance value decreases. Reward calculation unit 73 increases the reward "r" by specifying "1" as the value for the reward. Note that the reward value is not limited to "1". Conversely, reward calculation unit 73 decreases the reward "r" when the maximum performance value increases. Reward calculation unit 73 decreases the reward "r" by specifying "-1" as the value for the reward. Note that the reward value is not limited to "-1".

[0152] The function update unit 74 updates the function, which is a model for determining the operating command 67, according to the reward calculated by the reward calculation unit 73. The function can be updated, for example, by updating the action value table according to the data set. The action value table is a data set in which any action and its action value are stored together in tabular form. For example, in the case of Q-learning, the action value function Q(s) expressed by the formula (8) above is t , a t ) used as a function to determine operating command 67.

[0153] Fig. Figure 12 is a flowchart showing the processing of the learning device 61 in the controller 60 according to the fourth embodiment. Referring to the flowchart of Fig. 12 describes an enhancement learning procedure that updates the action value function Q(s, a).

[0154] In step S11, the learning device 61 acquires the operating information 65 and the operating command 67 through the data acquisition unit 71. That is, the learning device 61 acquires the training data 76. The data acquisition unit 71 outputs the data set obtained by compiling the training data 76 to the model generation unit 72.

[0155] In step S12, the learning device 61 calculates the reward using the reward calculation unit 73. The reward calculation unit 73 calculates the reward for a combination of the operating information 65 for each of the carriers 16 and the operating command 67 for each of the carriers 16. The reward calculation unit 73 increases or decreases the reward based on the maximum performance value.

[0156] In step S13, the learning device 61 updates the action value function through the function update unit 74. The function update unit 74 updates the action value function Q(s, a) based on the reward calculated in step S12. The learning device 61 updates the action value function Q(s) stored in the memory unit 75 for trained models. t ,a t ).

[0157] In step S14, the learning device 61 determines, via the function update unit 74, whether the action value function Q(s, a) has converged or not. The function update unit 74 determines that the action value function Q(s, a) has converged if the action value function Q(s, a) is no longer updated in step S13.

[0158] If it is determined that the action value function Q(s, a) has not converged (No in step S14), the learning device 61 returns to step S11 of the procedure. If, however, it is determined that the action value function Q(s, a) has converged (Yes in step S14), the learning device 61 terminates the processing according to the procedure described in Fig. The procedure shown in Figure 12 is described. It should be noted that the learning device 61 can continue learning by returning to step S11 of the procedure after step S13, without making the determination in step S14. The trained model memory unit 75 stores the trained model 66, which is the generated action value function Q(s, a).

[0159] The fourth embodiment describes the case in which reinforcement learning is used as the learning algorithm employed by the learning device 61, but learning other than reinforcement learning can also be used as the learning algorithm. The learning device 61 can perform machine learning using a known learning algorithm that is not reinforcement learning, such as deep learning, neural networks, genetic programming, inductive logic programming, or support vector machines.

[0160] The in Fig. 10 and Fig. The learning device 61 shown in Figure 11 is a device built into the controller 60. The learning device 61 can be a device outside the controller 60. The learning device 61 as a device outside the controller 60 is included in the conveyor system 1. The learning device 61 can be a device that can be connected to the controller 60 via a network. The learning device 61 can be a device on a cloud server. In the Fig. In the example shown in Figure 11, the storage unit 75 for trained models is integrated into the learning device 61. The storage unit 75 for trained models can also be located outside the learning device 61.

[0161] The learning device 61 can learn the operating command 67, which reduces the maximum power value according to a data set created for several of the conveyor systems 1. The learning device 61 can acquire the operating information 65 and the operating command 67 from several conveyor systems 1 used at the same location or from several conveyor systems 1 used at different locations. The operating information 65 and the operating command 67 can be collected from several conveyor systems 1 that are operated independently at multiple locations. After the operating information 65 and the operating command 67 have been acquired from the multiple conveyor systems 1, a new unit of conveyor system 1 can be added to the target from which the operating information 65 and the operating command 67 are acquired.After the operating information 65 and the operating commands 67 have been acquired by the multiple conveyor systems 1, some of the multiple conveyor systems 1 can be excluded from the target from which the operating information 65 and the operating commands 67 are acquired.

[0162] The learning device 61, which performed the learning for one of the support systems 1, can perform the learning for another of the support systems 1. The learning device 61, which performs the learning for the other of the support systems 1, can update the trained model 66 by performing the relearning for the other of the support systems 1.

[0163] Fig. Figure 13 is a diagram showing an exemplary configuration of the operating command generation device 62, which is included in the controller 60 according to the fourth embodiment. The operating command generation device 62 includes a function as an inference device that infers the operating command 67 from the operating information 65. The operating command generation device 62 includes a data acquisition unit 77 and an inference unit 78.

[0164] The data acquisition unit 77 receives the operating information 65 for each of the multiple carriers 16 included in the conveying system 1. The data acquisition unit 77 records the operating information 65 as inference data. The operating information 65 recorded by the data acquisition unit 77 is input into the inference unit 78. The trained model 66, stored in the memory unit 75 for trained models of the learning device 61, is input into the inference unit 78. The inference unit 78 infers the operating command 67 by inputting the operating information 65 into the trained model 66. The inference unit 78 outputs the operating command 67 as an inference result to the position command generation device 63.

[0165] Fig. Figure 14 is a flowchart representing a processing of the operating command generation means 62, the position command generation means 63 and the coil drive command generation means 64 according to the fourth embodiment, which are included in the control 60.

[0166] In step S21, the operating command generation device 62 acquires the operating information 65 of each of the carriers 16 through the data acquisition unit 77. The data acquisition unit 77 outputs the acquired operating information 65 to the inference unit 78.

[0167] In step S22, the operating instruction generator 62 creates the operating instruction 67 by inputting the operating information 65 into the trained model 66 in the inference unit 78. The operating instruction generator 62 outputs the generated operating instruction 67 to the position instruction generator 63.

[0168] In step S23, the position command generation device 63 generates the position command 68 based on the operating command 67. The position command generation device 63 outputs the generated position command 68 to the coil drive command generation device 64.

[0169] In step S24, the coil drive command generator 64 generates the coil drive command 69 based on the position command 68. The coil drive command generator 64 sends the generated coil drive command 69 via the data communication lines 14 to each of the conveyor path units 11. Subsequently, the operating command generator 62, the position command generator 63, and the coil drive command generator 64 terminate processing according to the procedure described in Fig. 14 shown sequence.

[0170] According to the fourth embodiment, the conveying system 1 comprises the learning device 61 and the operating command generation device 62 as an inference device, whereby the operating command 67 can be inferred, which reduces the maximum power value. This allows the conveying system 1 to reduce the load on each of the conveying path units 11.

[0171] Next, the hardware for implementing the controllers 12 and 60 according to the first to fourth embodiments is described. The controllers 12 and 60 are each implemented by a processing circuit. The processing circuit can be a circuit in which a processor executes software, or a circuit designed for a specific purpose.

[0172] If the processing circuit is implemented by the software, the processing circuit is, for example, a control circuit 80, which is in Fig. 15 is shown. Fig. Figure 15 is a diagram showing an exemplary configuration of the control circuit 80 according to the first to fourth embodiments. The control circuit 80 comprises 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 from outside the control circuit 80 and forwards 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.

[0173] In the case where the processing circuit is in Fig. In the control circuit 80 shown in Figure 15, the controllers 12 and 60 are implemented by software, firmware, or a combination of both. The software or firmware is described as programs and stored in memory 83. The processing circuit implements the functions of the controllers 12 and 60 by having the processor 82 read and execute the programs stored in memory 83. That is, the processing circuit includes memory 83 for storing the programs whose execution leads to the processing of the controllers 12 and 60. In other words, these programs cause a computer to execute the procedures and methods associated with the controllers 12 and 60.

[0174] The processor 82 is a CPU. The processor 82 can be a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP. The memory 83 corresponds, for example, to non-volatile or volatile semiconductor memory such as random access memory (RAM), read-only memory (ROM), flash memory, erasable programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM (registered trademark)), a magnetic disk, a flexible disk, an optical disk, a compact disc, a mini-disc, a digital versatile disc (DVD), or the like.

[0175] Fig. 15 is an example of the hardware in the case that the control 12 and 60 are implemented by the processor 82 and the memory 83, which are intended for general purposes, although the control 12 and 60 may be implemented by a purpose-built hardware circuit. Fig. Figure 16 is a diagram showing an exemplary configuration of a hardware circuit 85, which is intended for use according to the first to fourth embodiments.

[0176] The dedicated hardware circuit 85 comprises the input unit 81, the output unit 84, and a processing circuit 86. The processing circuit 86 can be a single circuit, a complex 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 a combination of these elements. The functions of the individual controllers 12 and 60 can be implemented individually or jointly by the processing circuit 86. It should be noted that the controllers 12 and 60 can each be implemented by a combination of the control circuit 80 and the hardware circuit 85.

[0177] In the case where the learning device 61 is the device outside the controller 60, the learning device 61 is implemented by a processing circuit as in the controllers 12 and 60. The processing circuit that implements the learning device 61 is the one in Fig. Control circuit 80 shown in 15 or the one in Fig. 16 purpose-built hardware circuits shown 85.

[0178] Specific distribution or integration modes of the components in the conveying system 1 according to the first to fourth embodiments are not limited to those described in the first to fourth embodiments. All or some of the components in the conveying system 1 can be functionally or physically distributed or integrated into units of any size. Reference symbol list 1 Conveyor system; 10. Funding path; 11, 11A, 11B, 11C, 11D, 11E, 11F, 11G, 11H Conveyor path unit; 12, 60 control; 13 Direct current supply; 14 Data communication lines; 15 DC power supply bus; 16, 16A, 16B, 16C, 16D carriers; 17A, 17B, 42 Arrow; 20 coils; 21 inverters; 22 Current sensor; 23 Capacitor; 24 Power control; 25 linear scale; 26 Position sensor; 27 82 processor; 28 communication slave station; 31 P-Bus; 32 N-Bus; 33 Voltage detector; 34 Temperature sensor; 40 41 Permanent magnet; 51, 52, 56 curve; 53, 54, 55, 57, 58, 59 point; 61 Learning device; 62 Operating command generation equipment; 63 Position command generation device; 64 Coil drive command generating means; 65 Operational information; 66 trained models; 67 Operating command; 68 Position command; 69 Coil drive command; 71, 77 Data acquisition unit; 72 Model generation unit; 73 Reward calculation unit; 74 Function update unit; 75 storage units for trained models; 76 training data points; 78 inference unit; 80 Control circuit; 81 Input unit; 83 storage locations; 84 output units; 85 Hardware circuitry; 86 processing circuit.

Claims

Conveyor system (1) with a plurality of conveying path units (11A to 11H) forming a conveying path (10) along which one or more conveying bodies move, wherein each plurality of conveying path units (11A to 11H) comprises: a plurality of drive units to be supplied with energy to generate a thrust force that moves the conveying body; and a processor (27) for determining whether each of the plurality of drive units is in an overload state, and also for determining whether the conveying path unit (11) is in an overload state, and wherein in each of the plurality of conveying path units (11A to 11H) the processor (27) performs an overload protection operation which reduces the temperature of the drive unit determined to be in the overload state or the temperature of the conveying path unit (11) determined to be in the overload state. Conveyor system (1) according to claim 1, wherein in a case where at least one of the plurality of drive units in one of the plurality of conveying path units (11A to 11H) is determined to be in an overload state, or in a case where one of the plurality of conveying path units (11A to 11H) is determined to be in an overload state, the plurality of conveying path units (11A to 11H) performs the overload protection processing to stop or delay all the conveyed bodies on the conveying path (10). Conveyor system (1) according to claim 1, wherein in a case in which at least one of the plurality of drive units in one of the plurality of conveying path units (11A to 11H) is determined to be in an overload state, the conveying path unit (11) comprising the drive unit determined to be in an overload state performs the overload protection processing to stop or delay the conveying body. Conveyor system (1) according to claim 1, wherein in a case where one of the plurality of conveying path units (11A to 11H) is determined to be in the overload state, the conveying path unit (11) which is determined to be in the overload state performs the overload protection processing to stop or delay the conveying body. Conveyor system (1) according to claim 1, wherein in a case in which at least one of the plurality of drive units in one of the plurality of conveying path units (11A to 11H) is determined to be in the overload state, the processor (27) of the conveying path unit (11) comprising the drive unit that is in the overload state stops an excitation to the drive unit that is in the overload state. Conveyor system (1) according to one of claims 1 to 5, wherein the drive unit comprises a component which is to be monitored to determine whether it is in the overload state, and wherein the processor (27) determines whether the component is in the overload state or not by comparing a predefined first criterion with a square mean of a current flowing through the component and a time period during which the current flows through the component, wherein the first criterion is a relationship between a first load determination value, which is a threshold value of the current flowing through the component when the component is not in the overload state and when the component is in the overload state, and the time period during which the current flows through the component. Conveyor system (1) according to claim 6, wherein the drive unit comprises a first component and a second component, each of which are the components to be monitored, wherein the first component is an inverter (21), and wherein the second component is a coil (20) for generating an electromagnetic force which is the thrust force provided by the power supplied by the inverter (21). Conveyor system (1) according to one of claims 1 to 5, wherein the processor (27) determines whether the conveyor path unit (11) is in the overload state or not by comparing a predefined second criterion with a loss of the conveyor path unit (11) and a time period during which a load is exerted on the conveyor path unit (11), wherein the second criterion is a relationship between a second load determination value, which is a threshold value for the loss of the conveyor path unit (11) when the conveyor path unit (11) is not in the overload state and when the conveyor path unit (11) is in the overload state, and the time period during which the load is exerted on the conveyor path unit (11). Conveyor system (1) according to claim 8, wherein the second load determination value, which is different for each of the conveying path units (11A to 11H), can be set for the plurality of conveying path units (11A to 11H). Conveyor system (1) according to claim 8 or 9, wherein in the second criterion the second load determination value converges to a constant value over time, and wherein a maximum rated loss, which is the loss of the conveying path unit (11) when the second load determination value is the constant value, is less than the loss of the conveying path unit (11) when a value of the current flowing through each of the plurality of drive units is a maximum rated current value of the drive unit. Conveyor system (1) according to one of claims 1 to 10, wherein the processor (27) determines, on the basis of a square mean of the current flowing through the plurality of drive units, whether the conveyor path unit (11) is in the overload state or not. Conveyor system (1) according to one of claims 1 to 10, wherein the processor (27) determines, on the basis of a detected result of the temperature of the conveying path unit (11), whether the conveying path unit (11) is in the overload state or not. Conveyor system (1) according to one of claims 8 to 10, wherein the processor (27) of each of the plurality of conveying path units (11A to 11H) determines whether the conveying path unit (11) is in a high load state or not, in which the conveying path unit (11) is expected to reach the overload state, and wherein, in a case in which one of the plurality of conveying path units (11A to 11H) is determined to be in the high load state, the processor (27) of a second conveying path unit, which is the conveying path unit adjacent to a first conveying path unit, which is the conveying path unit determined to be in the high load state, determines, on the basis of the second criterion, according to which a correction is made to set the second load determination value less than a preset value, whether the second conveying path unit is in the overload state or not. Conveyor system (1) according to claim 13, comprising: a controller (12) for controlling a movement of the conveying body, wherein the first conveying path unit, which is determined to be in the state of high load, informs the controller (12) that the first conveying path unit is in the state of high load, and wherein the processor (27) of the second conveying path unit performs the correction according to the second criterion when it receives a message from the controller (12) that the first conveying path unit is in the state of high load. Conveyor system (1) according to one of claims 8 to 10, comprising: a controller (12) for controlling a movement of the conveying body, wherein the controller (12) determines whether each of the plurality of conveying path units (11A to 11H) is in a high load state in which the conveying path unit (11) is expected to reach the overload state, and wherein, in a case in which one of the plurality of conveying path units (11A to 11H) is determined to be in the high load state, the processor (27) of a second conveying path unit, which is the conveying path unit adjacent to a first conveying path unit, which is the conveying path unit that is determined to be in the high load state, determines whether the second conveying path unit is in the overload state or not, based on the second criterion, according to which a correction is made to set the second load determination value less than a preset value. Conveyor system (1) according to claim 15, wherein the control (12) performs the correction according to the second criterion for the second conveying path unit and communicates the second criterion according to which the correction was performed to the second conveying path unit. Conveyor system (1) according to any one of claims 1 to 5, comprising: a learning device (61) comprising: a data acquisition unit (71) for acquiring training data (76) comprising operating information (65) and an operating command (67), wherein the operating information (65) is information specifying a movement plan for each of the plurality of conveyed bodies on the conveying path (10), and wherein the operating command (67) specifies a movement mode for each of the plurality of conveyed bodies; and a model generation unit (72) for generating a trained model (66) based on the training data (76), which is to be used to infer the operating command (67) from the operating information (65). Conveyor system (1) according to any one of claims 1 to 5, comprising: an operating command generation means (62) for generating an operating command (67) that specifies a movement mode for each of the plurality of conveyed bodies, wherein the operating command generation means (62) comprises: a data acquisition unit (77) for acquiring operating information (65), which is information that specifies a movement plan for each of the plurality of conveyed bodies on the conveying path (10); and an inference unit (78) for inferring the operating command (67) by inputting the operating information (65) into a trained model (66) which is used to infer the operating command (67) from the operating information (65).

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