JP7559635B2 - CONTROL SYSTEM, DRIVER, ELECTRIC MOTOR, CONTROL DEVICE, AND CONTROL METHOD - Google Patents

Description

The present invention relates to a control system, a driver, an electric motor, a control device, and a control method.

The power line and the encoder signal line are wired separately between the servo driver (servo drive, or simply driver) and the electric motor. This makes the wiring work a heavy burden. As a result, the wiring work also increases costs. Therefore, for example, in a servo system consisting of multiple motors with built-in serial encoders, a communication line connecting the servo drive and the serial encoder, and a power line connecting the serial encoder and the servo drive, a system has been proposed in which the power line and the communication line are common and connected in a daisy chain (for example, see Patent Document 1 below).

JP 2007-181340 A JP 2006-304461 A

However, as the control system becomes more complex, it is possible that multiple drivers and motors are connected to a control device such as a PLC.

The objective of the present invention is to simplify signal lines and reduce the burden and cost of wiring work in complex control systems that include multiple drivers.

An embodiment according to the invention is exemplified by the following control system: In a first aspect, the control system comprises:
A plurality of control mechanisms including a driver for driving an electric motor and an electric motor having an encoder for detecting a physical quantity related to the rotation of the electric motor;
A control device that controls the plurality of control mechanisms,
the drivers, the motors, and the control devices included in the plurality of control mechanisms are connected to a network having a daisy chain structure capable of packet transfer and power supply to the encoders,
the control device sets a command addressed to each driver in an area corresponding to each driver of the plurality of control mechanisms within the packet, and transmits the packet to a next connection destination in the daisy chain structure;
Each driver of the plurality of control mechanisms obtains a command addressed to itself from the control device from a region corresponding to itself in a packet received from a source of the daisy chain structure, and transmits the received packet to a next destination in the daisy chain structure;
Each electric motor of the multiple control mechanisms sets the physical quantity detected by the encoder possessed by that electric motor in the area corresponding to it in the received packet, and transmits the received packet to the next destination in the daisy chain structure.

In this control system, each motor can transfer the physical quantity detected by its own encoder to the driver connected in a daisy chain structure by setting the physical quantity in the packet corresponding to the motor. Therefore, communication lines for transferring the physical quantities detected by the encoders of the motors between the driver and the motors are not required.

In a second aspect, the packet is forwarded by looping back at an end of the network having the daisy chain structure;
The drivers of the plurality of control mechanisms each obtain the physical quantity detected in the electric motor corresponding to the respective driver from the region corresponding to the driver in the packet that has been returned and transferred.

In this control system, the physical quantities detected by the encoders of each electric motor are passed to the drivers connected in the daisy chain structure by packets that are folded back and forwarded at the end of the daisy chain network. Therefore, a packet making one round trip through the daisy chain structure can execute commands from the control device to the driver and pass the physical quantities from the electric motor to the driver.

In a third aspect, in each of the multiple control mechanisms, the driver is connected to the daisy chain structure at a position closer to the control device than the corresponding electric motor. With this arrangement, a packet makes a round trip through the daisy chain structure, thereby realizing the transmission of commands from the control device to the driver and the delivery of the physical quantity from the electric motor to the driver.

In a fourth aspect, the control device is connected to a start point of the daisy chain structure and transmits the packet;
While the transmitted packet is traveling back and forth between the terminal end of the daisy chain structure, each motor of the plurality of control mechanisms sets the physical quantity in the received packet;
After the transmitted packet has traveled back and forth once between the terminal of the daisy chain structure, the control device re-transmits the packet that has traveled back and forth once;
The drivers of the respective control mechanisms acquire the physical quantities detected in the electric motors corresponding to the respective drivers from the regions corresponding to the respective drivers in the retransmitted packets.

With this configuration, the packet travels back and forth twice between the ends of the daisy chain structure, realizing commands from the control device to the driver and the transfer of the physical quantity from the motor to the driver. In this case, the driver does not need to be connected to the daisy chain structure at a position closer to the control device than the corresponding motor. This increases the freedom of arrangement and connection between the driver and the corresponding motor.

In a fifth aspect, one embodiment of the present invention can be identified as the driver described above.

In a sixth aspect, one embodiment of the present invention can be identified as the electric motor described above.

In a seventh aspect, one embodiment of the present invention can be identified as the above-mentioned control device.

In an eighth aspect, one embodiment of the present invention can be identified as a control method in a control system.

In at least one aspect of this embodiment, in a complex control system including multiple drivers, signal lines are simplified, thereby reducing the burden and cost of wiring work.

FIG. 1 is a diagram illustrating an example of an application scene of a control system according to an embodiment. FIG. 2 is a diagram illustrating a control system according to a comparative example. FIG. 3 is a diagram illustrating a control system according to the first embodiment. FIG. 4 is a diagram illustrating another arrangement of the motor and the driver in the first embodiment. FIG. 5 is a diagram illustrating a control system according to the first embodiment. FIG. 6 is a diagram illustrating a control system using ducts to protect or shield wiring. FIG. 7 is a diagram comparing a control system including a sensor according to a comparative example with the control system according to the first embodiment. FIG. 8 is a diagram illustrating the structure of process data included in a packet according to the first embodiment, and the processing of the nodes when the packet circulates around the daisy chain for the first time. FIG. 9 is a diagram illustrating the process of the node when the packet circulates around the daisy chain for the second time. FIG. 10 is a diagram illustrating the processing of the control system of the first embodiment. FIG. 11 is a diagram illustrating the process after a packet is returned in the reverse direction of the daisy chain. FIG. 12 is a diagram illustrating a configuration of process data included in a packet according to the second embodiment and processing of a node when the packet circulates around the daisy chain. FIG. 13 is a diagram illustrating the process of the control system of the second embodiment. FIG. 14 is a diagram illustrating the process of the control system of the second embodiment.

An embodiment according to one aspect of the present invention (hereinafter, also referred to as "the present embodiment") will be described below with reference to the drawings. However, the present embodiment described below is merely an example of the present invention in every respect. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. In other words, in implementing the present invention, a specific configuration according to the present embodiment may be appropriately adopted. Note that the data appearing in this embodiment is explained in natural language. However, more specifically, the data appearing in this embodiment is processed in pseudo-language, commands, parameters, machine language, etc. that can be recognized by a computer. Furthermore, these data are stored in the form of binary data, character strings, etc. in the storage area of the main storage device or secondary storage device.

<Application Examples>
First, an example of a scene to which the present invention is applied will be described with reference to FIG. 1. FIG. 1 illustrates a control system 100 according to the present embodiment. However, as shown in FIG. 1, the control system 100 is, for example, a factory automation system, a collection and delivery system of a carrier's collection and delivery center, a mail-order company's dispatch center, an articulated robot, a construction machine, or the like. As shown in FIG. 1, the control system 100 has a plurality of motors M1 to M4, servo drivers (hereinafter simply referred to as drivers) D1 to D4 that drive the motors M1 to M4, and a control device 10. In FIG. 1, the motors M1 to M4 and the drivers D1 to D4 are connected by power lines LP1 to LP4 for supplying power from the drivers D1, etc. to the motors M1, etc. Note that the motors are also called electric motors.

These motors M1, etc., drivers D1, etc., and control device 10 are connected by a communication line LC. The communication line LC connects the control device 10, drivers D1, etc., and motors N1, etc. in a daisy chain to form a network N1. A daisy chain is one way of connecting nodes that make up a network. In a daisy chain, a second node is connected to a first node, and a third node is connected to the second node. Note that the network N1 is not limited to a single daisy chain, and can be branched into multiple paths by a branching section BR.

Here, the network N1 may be, for example, EtherCATP (registered trademark).
In the network N1, the control device 10 is the master node, and the motors M1, etc., the driver D1, etc. are slave nodes.

As shown in FIG. 1, the control system 100 can be said to be a system that controls, for example, four axes. However, the number of slave nodes is not limited to eight as shown in FIG. 1. In other words, the number of motors M1, etc. and the number of drivers D1, etc. may each be three or less, or five or more.

In network N1, the possible areas for inputting and outputting data within a packet are determined for each slave node. Then, a packet sent from the master node reaches the most downstream (end) slave node, is turned around, and returns to the master node again. In the time it takes to make one circuit of network N1, data exchange between the master node and all slave nodes is completed.

Furthermore, in network N1, the communication line LC includes, for example, an Ethernet (registered trademark) signal line and a power line. Therefore, the communication line LC includes, for example, a data line capable of sending and receiving information in an IEEE 802.3 standard Ethernet (registered trademark) frame, and a power line capable of supplying power from the master node to the slave node. Network N1 can be said to be an example of a network with a daisy chain structure capable of packet transfer and supplying power to each encoder.

The control device 10 is, for example, a device called a Programmable Logic Controller (PLC), a servo controller, etc. The control device 10 has a built-in Central Processing Unit (CPU) such as a microprocessor and a memory, and controls the device by a program that can be changed by the user. The control device 10 has a communication interface of a communication line LS. The CPU of the control device 10 executes communication through the communication line LS connected in a daisy chain.

The driver D1 etc. receives target value instructions from the control device 10, supplies power to the motor M1 etc., and controls the motor M1 etc. The target values are, for example, the rotational position, rotational speed, and rotational force of the shaft of the motor M1 etc. The driver D1 etc. has a controller including a CPU and a communication interface of the communication line LS, and performs communication through the communication line LS connected in a daisy chain.

The motor M1 etc. has a communication device and an encoder inside. The communication device has a controller including a CPU and a communication interface of a communication line LS, and executes communication through the communication line LS connected in a daisy chain. The encoder detects physical quantities related to the rotation of the motor, such as the rotation position (rotation angle), number of rotations, or rotation speed of the shaft of the motor M1 etc. The encoder receives power supply from the power line of the communication line LC, and detects the rotation of the shaft of the motor M1 etc. by operating, for example, an optical sensor. The communication device then notifies the control device 10 or the driver D1 etc. of the physical quantities detected by the encoder (rotation position, number of rotations, rotation speed, etc.) through the data line of the communication line LC. The driver D1 etc. controls the motor M1 etc. so that the rotation position, rotation speed, rotation force, etc. of the motor M1 approach the target value based on the physical quantities detected by the encoder. The combination of the driver D1 etc. and the motor M1 etc. can be said to be an example of a control mechanism.

Comparative Example
2 illustrates a control system 500 according to a comparative example. The control system 500 includes a control device 50, drivers D51 and D52, and motors M51 and M51. In the control system 500, the control device 50 and the driver D1 are connected by a communication line LC50 to form a motion network, as in the case of FIG. 1. However, in the comparative example, the drivers D51 and D52 supply power to the motors M51 and M52 through power lines LP51 and LP52. Also, in the comparative example, the drivers D51 and D52 receive detection values such as the rotational position and rotational speed of the motors M51 and M52 from the encoders attached to the motors M51 and M52 via encoder lines LE51 and LE52.

In other words, in the comparative example, separate wiring is required between the driver D51 etc. and the motor M51 etc. using power lines LP1 etc. and encoder lines LE1 etc. Also, to avoid the effects of noise, the power lines and encoder lines must be installed separately. Therefore, if there is a distance between the driver D51 etc. and the motor M51 etc., long-distance power lines LP1 etc. and encoder lines LE1 etc. will have to be wired separately. Also, the communication line LC50 for the motion network and the encoder line LE51 etc. are each dedicated communication lines. Therefore, the user must prepare dedicated cable line types for each.

<Embodiment 1>
Hereinafter, the control systems 100A to 100D of the present embodiment will be described with reference to FIGS.

(composition)
Fig. 3 is a diagram illustrating a control system 10A of this embodiment. As in Fig. 1, the control system 100A has a plurality of motors M1, M2, drivers D1, D2 for driving the motors M1, etc., and a control device 10. As in Fig. 1, in Fig. 3, the motors M1, M2 and the drivers D1, D2 are connected by power lines LP1, LP2 for supplying power from the driver D1, etc. to the motors M1, etc. The control system 100A can be said to be, for example, a system for controlling two axes.

Also, in FIG. 3, like FIG. 1, the motors M1, etc., the driver D1, etc., and the control device 10 are connected by a communication line LC. The communication line LC connects the control device 10, the driver D1, etc., and the motor M1, etc. in a daisy chain to form the network N1 illustrated in FIG. 1. Note that FIG. 3 does not illustrate the branching point BR of FIG. 1. However, in this embodiment and other embodiments described below, the daisy chain of the communication line LC can branch into multiple paths at the branching point BR. The control device 10, the driver D1, etc., and the motor M1, etc. are the same as those described in FIG. 1.

In the control system 100A, power is supplied from the driver D1 etc. to the encoder attached to the motor M1 etc. via the communication line LC. Then, the physical quantities of the motor D1 etc. detected by the encoder, such as the rotational position, number of rotations, and rotational speed, are notified to the control device 10 via the communication line LC. Therefore, in the control system 100A, there is no need to wire the encoder lines LE1, LE2 etc. individually from the control device 10 to the drivers D1, D2. In other words, a daisy chain of communication lines LC is all that is required.

Fig. 4 illustrates another arrangement of the motors M1, M2 and the drivers D1, D2 in this embodiment. In Fig. 4, it is assumed that the drivers D1, D2 are arranged in a position close to the control device 10, and the motors M1, M2 are arranged in a position away from the control device 10, the drivers D1, D2, etc. In this way, when the driver D1, etc. and the motor M1, etc. are arranged at a distance, the control system 100A in Fig. 3 does not require wiring such as the encoder line LE1, which is more effective than the comparative example in Fig. 21.

Figure 5 illustrates a control system 100B in which motors M1, M2 and drivers D1, D2 are arranged in the same manner as in the comparative example of Figure 2. For comparison, Figure 5 also illustrates a control system 500B having a similar configuration to Figure 2.

As shown in FIG. 5, in the control system 500B, an encoder line LE1 that connects the driver 51 and the motor M51, and an encoder line LE2 that connects the driver 52 and the motor M52 are wired. On the other hand, in the control system 100B of this embodiment, if a single daisy chain of communication lines LC is wired, physical quantities such as the rotational position and rotational speed detected by the encoders attached to the motors M1 and M2 can be fed back to the drivers D1 and D2 from the motors M1 and M2.

Figure 6 illustrates an example of a control system 100C of this embodiment that uses ducts T1 and T2 to protect or shield the wiring. For comparison, Figure 6 also illustrates a control system 500C that uses ducts T51 and T52 in a configuration similar to that of Figure 2.

As shown in FIG. 6, in the control system 500C of the comparative example, the power lines LP51, LP52 and the encoder lines LE51, LE52 are housed in different ducts T51, T52, respectively, to prevent interference due to noise. Similarly, in the control system 100C of this embodiment, the power lines LP1, LP2 and the communication line LC are housed in different ducts T1, T2, respectively.

As shown in FIG. 6, in the case of the control system 500C, two encoder lines LE51 and LE52 need to be passed through the duct T51. On the other hand, in the control system 100C of this embodiment, only one communication line LC is required to pass through the duct T2. Note that FIG. 6 is an example of the control system 100C that controls two axes. When controlling three axes, in the case of the control system 500C of the comparative example, three encoder lines pass through the duct T51, and in the case of the control system 100C of this embodiment, only one communication line LC is required to pass through the duct T2. This is a generalized effect that, in a system that controls N (integer) axes, N encoder lines can be replaced with one communication line LC. In addition, for example, when a control panel including the control device 10, drivers D1, D2, etc. is installed in a position away from the motors M1, M2, etc., the effect of this embodiment is particularly large.

Figure 7 is a diagram comparing a control system 500D of a comparative example including sensors SN51, etc., with a control system 100D of this embodiment including sensors SN1, etc. The control system 500D illustrated on the left side of Figure 7 is a control system 500C of Figure 6 to which sensors SN51 and SN52 have been added. On the other hand, the control system 100D illustrated on the right side of Figure 7 is a control system 100C of Figure 6 to which sensors SN1 and SN2 have been added.

In the control system 500D, the sensors SN1 and SN2 are connected to the drivers D51 and D52 by the sensor lines LS51 and LS52 that pass through the duct T51, respectively. On the other hand, in the control system 100D of this embodiment, the sensors SN1 and SN2 only need to be connected to the daisy chain of the communication line LC. Therefore, in the control system 100D, instead of the two sensor lines LS51 and LS52, a single daisy chain communication line LS is wired. This is also true when the number of sensors LS1, etc. is increased to N (an integer). In addition, for example, the effect of this embodiment is particularly large when the control panel including the control device 10, drivers D1, D2, etc. is installed in a position away from the motors M1, M2, etc.

Here, there is no limitation on the type and number of sensors SN1, SN2, etc. The sensors SN1, SN2, etc. have a detection unit, a controller including a CPU, and a communication interface with the daisy-chain communication line LS. The detection unit detects data including at least one of various physical quantities, chemical components, biological information, images, sounds, etc. The physical quantities include, for example, mechanical or electromagnetic measurements, measurements from the environment, etc. The chemical components include, for example, molecules and other components contained in a substance or the environment. The biological information includes, for example, information obtained from the human body or living organisms, biological information obtained from the environment, etc. The controller sends the data detected by the detection unit from the communication interface to the next destination via the daisy-chain communication line LS. These data are set in an input/output possible area corresponding to the sensor SN1, etc., in the packet exchanged on the communication line LS. That is, the sensor SN1 etc. detects data including at least one of physical quantities, chemical components, biological information, images, and sounds, sets the detected data in an area corresponding to itself in a packet received from a sender in the daisy chain structure, and transmits the received packet to the next destination in the daisy chain structure. In this way, the data detected by the sensor SN1 etc. is transmitted to the drivers D1, D2 etc., or the control device 10.

(Packet process data configuration and input/output timing)
1, 3 to 7, the control device 10 and the like can be said to be located at the starting point of the daisy chain. That is, the control device 10, driver D1, motor M1, driver D2, motor M2, and so on are connected in a daisy chain structure. Below, input and output of data to and from packets in this daisy chain structure will be described together with the structure of process data in the packets.

Figure 8 illustrates an example of the structure of process data contained in packets exchanged via a daisy chain using the communication lines LC of the control systems 100A to 100D of this embodiment. The process data is the data portion of the packet excluding the header information and frame check sequence. In addition to the structure of the process data, arrows in Figure 8 also illustrate the processing of the control device 10 and the processing of the slave node accessed when the packet circulates around the daisy chain for the first time.

As shown in FIG. 8, the process data is specified in advance as a readable/writable area for each of the drivers D1, D2, ..., which are slave nodes incorporated in the daisy chain, and the motors M1, M2, .... Such specification may be performed, for example, so that the nodes can be identified by node numbers in the daisy chain network. Such specification may be performed, for example, when each slave node is connected to the daisy chain. Also, such specification may be performed, for example, in the initial setting between the master node and the slave node. As shown in the figure, in this embodiment and other embodiments described below, the motors M1, M2, etc. are accompanied by encoders E1, E2, etc. The process data exemplified in FIG. 8 includes a command C1 addressed to the driver D1, a feedback F1 addressed to the driver D1, a command C2 addressed to the driver D2, a feedback F2 addressed to the driver D2, .... Note that in this embodiment, the number of slave nodes of the drivers D1, etc. and the motors M1, etc. is not limited to two each (four in total).

For example, the control device 10 writes a command C1 addressed to the driver D1 and a command C2 addressed to the driver D2 in the respective areas of the packet (arrows A1, A2), and sends the packet to the daisy chain. In this embodiment, the daisy chain is formed in the order of the driver D1, the motor M1, the driver D2, and the motor M1, as shown in FIG. 3. As already mentioned, the control device 10, the driver D1, etc., the motor M1, etc., and the sensor SN1, etc. are provided with a communication interface of the communication line LS, and communication is performed by these. However, in the description of this embodiment, it is described that the control device 10, the driver D1, etc., the motor M1, etc. communicate with each other. The control device 10 transfers the packet to the driver D1.

Then, driver D1 receives the packet and reads out command C1 addressed to driver D1 from the process data (arrow A3). Command C1 is, for example, a target value for motor M1's rotational position, rotational speed, rotational force, etc. Driver D1 transfers the packet to motor M1 and controls motor M1 according to command C1 read out from the process data. Note that at this point, feedback F1 addressed to driver D1 has not been set, so driver D1 cannot obtain feedback F1.

Next, when motor M1 receives the packet, it writes the physical quantities, such as the rotational position, number of rotations, and rotational speed, detected by encoder E1 attached to motor M1 into the feedback F1 area addressed to driver D1 (arrow A4). Motor M1 then transfers the packet to driver D2.

Next, when driver D2 receives the packet, it reads command C2 addressed to driver D2 from the process data (arrow A5). Driver D2 transfers the packet to motor M2 and controls motor M2 according to command C2 read from the process data. Note that at this point, feedback F2 addressed to driver D2 has not been set, so driver D2 cannot obtain feedback F2.

Furthermore, when motor M2 receives a packet, it writes physical quantities such as the rotational position, number of rotations, and rotational speed detected by encoder E2 attached to motor M2 in the feedback F2 area addressed to driver D2 (arrow A6). Motor M2 then sends the packet back up the daisy chain addressed to driver D2. The packet is then transferred in the opposite direction up the daisy chain and returns to control device 10. Note that in this embodiment, the slave node does not perform input/output to the process data area while the packet is transferred in the opposite direction up the daisy chain. Control device 10 then sends the packet that was transferred back again toward driver D1.

In FIG. 9, the arrows show the process of the slave node accessed when the packet circulates the daisy chain for the second time. In this embodiment, in the second circulation of the packet, the control device 10 clears the commands from the first circulation (command C1 addressed to driver D1 and command C2 addressed to driver D2) (arrows A111, A12). However, instead of clearing the first command C1 addressed to driver D1 and command C2 addressed to driver D2, the control device 10 may set the access to this area by drivers D1 and D2 to be prohibited. Then, as in the first circulation, the control device 10 transfers the packet to driver D1.

When driver D1 receives the packet circulated for the second time, it reads feedback F1 addressed to driver D1 from the process data (arrow A7). Driver D1 transfers the packet to motor M1 and controls motor M1 according to command C1 and feedback F1 acquired in the first circumstance.

Next, when motor M1 receives the packet, the data has already been written to the feedback F1 area, so motor M1 transfers the packet directly to driver D2.

Next, when the driver D2 receives the packet circulated for the second time, it reads the feedback F2 addressed to the driver D2 from the process data (arrow A8). The driver D2 transfers the packet to the motor M2 and controls the motor M2 according to the command C2 and feedback F2 acquired in the first circumstance.

Next, when motor M2 receives the packet, the data has already been written to the feedback F2 area, so motor M2 simply returns the packet to driver D2.

The packet returned in this way is transferred in the opposite direction through the daisy chain and returned to the control device 10. The control device 10 then sets a new target value in the first round packet shown in FIG. 8, and sends a packet to the daisy chain that clears the feedback F1 and F2 areas or sets these areas to be writable. In this way, the control device 10 alternately sends to the daisy chain the packet circulating in the first round shown in FIG. 8 and the packet circulating in the second round that was returned in the first round shown in FIG. 9. In this manner, the control device 10 passes the target value to the drivers D1 and D2 of the slave nodes. The encoders E1 and E2 of the motors M1 and M2 also pass feedback to the drivers D1 and D2 via the control device 10.

(process)
The process of the control system 100A will be described with reference to Figures 9 and 10. Figures 9 and 10 illustrate the exchange of packets between the control device 10, the drivers D1 and D2, the motors M1 and M2, and the encoders E1 and E2 attached to the motors M1 and M2, and the process executed by them. In this process, the control device 10, acting as the master node, first instructs the slave nodes to perform initial settings (S1). The initial settings instruction may include, for example, a notification of each slave node's access permission area in the process data. Then, each slave node recognizes the area to be read and the area to be written by itself according to the initial settings instruction, and stores the area in each memory (S2 to S5). As already mentioned, such settings may be executed when each slave node is connected to a daisy chain.

Next, the control device 10 sets a command in the process data (S6) and sends out the packet (S7). The process of S6 is an example of setting a command addressed to each driver in an area in the packet that corresponds to each driver of multiple control mechanisms. The process of S7 is an example of sending the packet to the next connection in the daisy chain structure.

Then, driver D1 receives the packet (S8). Driver D1 then reads command C1 addressed to driver D1 from an area in the process data to which it is permitted to access (S9). The process of S9 is an example of obtaining a command addressed to itself from the control device 10 from an area corresponding to itself in a packet received from the sender of the daisy chain structure. Next, driver D1 sends the packet (S10) and controls motor M1 according to command C1 (S11). The process of S10 is an example of sending a packet to the next connection destination in the daisy chain structure.

Next, motor M1 receives the packet (S12). Then, motor M1 writes the physical quantity detected by encoder E1 in the feedback F1 area addressed to driver D1 (S13). The process of S13 is an example of setting the physical quantity detected by the encoder of each electric motor in the area corresponding to the motor itself in the received packet. Then, motor M1 sends out the packet (S14). The process of S14 is an example of sending the received packet to the next destination in the daisy chain structure.

Next, the driver D2 receives the packet (S15). Then, the driver D2 reads the command C2 addressed to the driver D2 from the area in the process data to which the driver D2 is permitted to access (S16). The process of S16 is also an example of obtaining a command addressed to the driver D2 from the area corresponding to the driver D2 in the packet received from the sender of the daisy chain structure. Next, the driver D2 sends out the packet (S17) and controls the motor M2 according to the command C2 (S18).

Then, motor M2 receives the packet (S19). Motor M2 writes the physical quantity detected by encoder E2 in the feedback F2 area addressed to driver D2 (S20). The process of S20 is also an example of setting the physical quantity detected by the encoder of each motor in the area corresponding to the motor in the received packet. Motor M1 then sends the packet back in the reverse direction of the daisy chain. The processes of S13 and S20 are also an example of setting a physical quantity in the packet received by each motor of multiple control mechanisms while the packet goes back and forth between the ends of the daisy chain structure.

Figure 11 illustrates the process after the packet is folded back in the reverse direction of the daisy chain. That is, motor M2 sends a packet toward driver D2 (S30). Then, each slave node sends a packet in the reverse direction of the daisy chain (S31 to S37). The process of S30 to S37 can be said to be an example of a packet being folded back and forwarded at the end of a network with a daisy chain structure. Also, the process of S7 in Figure 10 to S37 in Figure 11 can be said to have caused the packet to make a round trip once between the end of the daisy chain structure.

When the control device 10 receives the packet that has been returned and forwarded (S37), it sends the received packet back to the daisy chain as feedback (S38). The process of S38 is an example of sending a packet that has already made a round trip again.

Then, driver D1 receives the feedback packet (S39). Driver D1 then reads feedback F1 addressed to driver D1 from an area in the process data to which it is permitted to access (S40). The process of S40 is an example of acquiring physical quantities detected in the motors corresponding to each driver from an area corresponding to the driver in the packet that was sent again. Next, driver D1 sends a packet to motor M1 (S41), and controls motor M1 according to command C1 and feedback F1 acquired in the first round (S42).

Next, motor M1 receives the packet (S43) and sends it to driver D2 as is (S44). As a result, driver D2 receives the feedback packet (S45). Driver D2 then reads feedback F2 addressed to driver D2 from an area in the process data to which access is permitted (S46). The process of S46 is also an example of obtaining physical quantities detected in the motors corresponding to each driver from an area corresponding to the driver in the packet that was sent again. Next, driver D2 sends a packet to motor M2 (S47) and controls motor M2 according to command C2 and feedback F2 obtained in the first round (S48).

Then, motor M2 receives the packet (S49) and returns it to driver D2 (S50). After that, similar to S30 to S37, each slave node sends packets in the opposite direction of the daisy chain.

(Effects of the embodiment)
As described above, the control system 100A of the present embodiment has a configuration in which the control device 10, the driver D1, etc., and the motor M1 (including the encoder E1) are connected in a daisy chain by the communication line LC. The control device 10 becomes the master node, and the driver D1, etc., and the motor M1 (encoder E1) etc. become slave nodes. As a result, while the packet goes back and forth through the daisy chain, the control device 10 transmits a command including a target value to the driver D1, etc., and a physical quantity that is feedback information measured by the encoder E1 in the motor M1, etc. is added to the packet. Then, next, while the packet goes back and forth through the daisy chain again, the driver D1, etc. acquires this feedback information. Such two rounds (round trips) of the packet make the conventional encoder line LE1, etc. unnecessary. As a result, the load of wiring work is significantly reduced in the control system 100A including a plurality of drivers D1, etc., motors M1 (encoder E1), etc. This effect is large when the distance between the driver D1 and the motor M1 (encoder E1) is large, for example, as shown in Figures 4 and 5. This effect is also large when a duct D1 is used, for example, as shown in Figure 6. This effect is also large when a large number of sensors SN1 are used, as shown in Figure 7.
In this embodiment, in the daisy chain of Figs. 2 to 7, the driver D1, etc. is located closer to the control device 10 than the motor M1, etc., which is the control target. However, even if the driver D1, etc. is located farther from the control device 10 than the motor M1, etc., which is the control target, the processing of the control system 100A is applicable. That is, in the control system 100A of this embodiment, while the packet makes two round trips through the daisy chain, the control device 10 issues a command to the driver D1, etc., and the motor M1, etc. issues a feedback to the driver D1, etc., respectively. Therefore, in the control system 100A of this embodiment, there is no restriction on the positional relationship in the daisy chain between the driver D1, etc., and the motor M1, etc., which is the control target. That is, the driver D1, etc., and the motor M1, etc., which is the control target, can be flexibly arranged, improving the degree of freedom of the layout.

<Embodiment 2>
Hereinafter, the control system 100B of the second embodiment will be described with reference to Figs. 12 to 14. In the control system 100A of the first embodiment, while a packet makes two round trips through the daisy chain, a command from the control device 10 to the driver D1, etc. and a feedback from the motor M1, etc. to the driver D1, etc. are executed. Here, the feedback is the transmission of detection data of the encoder E1, etc. to the driver D1, etc. On the other hand, in the control system 100B of this embodiment, while a packet makes one round trip through the daisy chain, a command from the control device 10 to the driver D1, etc. and a feedback from the motor M1, etc. to the driver D1, etc. are executed. That is, a packet sent from the control device 10 as a master node is used to execute communication between slave nodes, that is, between the driver D1, etc. and the motor M1, etc. As a result, in the control system 100B, the response between the driver D1, etc. and the motor M1, etc. is improved.

(Packet process data configuration and input/output timing)
FIG. 12 illustrates the configuration of process data included in a packet exchanged through a daisy chain by the communication line LC of the control system 100B. FIG. 12 also illustrates the processing of each node when a packet circulates through the daisy chain. The process data includes a command C1 addressed to the driver D1, feedback F11, F12 addressed to the driver D1, a command C2 addressed to the driver D2, feedback F2 addressed to the driver D2, and so on. Note that FIG. 12 illustrates feedback F11, F12 addressed to the driver D1, but only one of them may be used. The feedback F11, F12 addressed to the driver D1 are provided because the packet passes through the motor M1 twice while traveling back and forth through the daisy chain, so that there are two opportunities for the physical quantity to be written.

As in the first embodiment (Figure 8), for example, the control device 10 writes a command C1 addressed to driver D1 and a command C2 addressed to driver D2 in the respective areas of the packet (arrows A21, A22), and sends the packet to the daisy chain. The daisy chain is formed in the order of driver D1, motor M1, driver D2, and motor M1, as in Figure 3 of the first embodiment.

When the driver D1 receives the packet, it reads out a command C1 for the driver D1 from the process data (arrow A23). The driver D1 transfers the packet to the motor M1 and controls the motor M1 according to the command C1 read out from the process data. At this point, as in the first embodiment (FIG. 8), the feedback F1 for the driver D1 has not been set, so the driver D1 cannot obtain the feedback F1.

Next, when motor M1 receives the packet, encoder E1 attached to motor M1 writes the detected physical quantities such as rotation position, number of rotations, and rotation speed in the feedback F1 area addressed to driver D1 (arrow A24). Motor M1 then transfers the packet to driver D2. Note that in control system 100B, if driver D1 only uses the feedback F12 area, motor M1 may transfer the packet directly to driver D2 without writing the physical quantities detected by encoder LE1 in the feedback F1 area.

Next, when driver D2 receives the packet, it reads command C2 addressed to driver D2 from the process data (arrow A25). Driver D2 transfers the packet to motor M2 and controls motor M2 according to command C2 read from the process data. Note that at this point, as in the first embodiment (FIG. 8), feedback F2 addressed to driver D2 has not been set, so driver D2 cannot obtain feedback F2.

Furthermore, when motor M2 receives the packet, encoder E2 attached to motor M2 writes the detected physical quantities such as rotation position, number of rotations, and rotation speed in the feedback F2 area addressed to driver D2 (arrow A26). Motor M1 then transfers the packet to driver D2. The packet is then transferred in the reverse direction through the daisy chain.

However, in this embodiment, during this reverse transfer, the driver D1 and the driver D2 obtain feedback from the motors M1 and M2, respectively. That is, first, when the driver D2 receives a packet sent in the reverse direction from the motor M2,
The feedback F2 addressed to the driver D2 is read from the process data (arrow A27). The driver D2 transfers the packet in the reverse direction to the motor M1 and controls the motor M2 according to the command C2 and feedback F2 acquired in the process of arrow A25.

Next, when motor M1 receives the packet, it writes the data detected by encoder E1 at this time to feedback F12 addressed to driver D1 (arrow A28). In the control system 100B, if driver D1 uses only the feedback F11 area, motor M1 may transfer the packet directly to driver D1, as in the first embodiment. In other words, control system 100B may use only one of feedbacks F11 and F12 addressed to driver D1.

Next, when driver D1 receives the packet, it reads feedback F11, F12 addressed to driver D1 from the process data (arrows A29, A30). Driver D1 transfers the packet in the opposite direction to control device 10, and controls motor M1 according to command C1 and feedback F11, F12 acquired in the process of arrow A23. Note that if motor M1 does not execute either process of arrow A24 or process of arrow A28, driver D1 may control motor M1 according to either feedback F11, F12 written by motor M1.

(process)
The process of the control system 100B will be described with reference to Fig. 13 and Fig. 14. Fig. 13 and Fig. 14 show an example of packet exchange between the control device 10, the drivers D1 and D2, the motors M1 and M2, and the encoders E1 and E2 attached to the motors M1 and M2, and the process executed by these. Of this process, the processes from S51 to S61 are similar to the processes from S1 to S11 in Fig. 10, and therefore the description thereof will be omitted.

When driver D1 sends a packet (S61), motor M1 receives the packet (S62). Motor M1 then writes the data detected by encoder E1 to the feedback F11 area addressed to driver D1 (S63). As described in FIG. 12, in the control system 100B, if driver D1 does not use the feedback F11 area and only uses the feedback F12 area, motor M1 may transfer the packet directly to driver D2 without writing it to the feedback F11 area. Motor M1 then sends the packet (S64).

Next, the processing of S65 to S70 is the same as the processing of S15 to S20 in FIG. 10, and therefore the description thereof is omitted. When the motor M2 writes the data detected by the encoder E2 to the feedback F2 area addressed to the driver D2 (S70), the motor M2 returns the packet in the reverse direction of the daisy chain. The processing of S70 is an example of a packet being returned and transferred at the end of a network with a daisy chain structure.

Figure 14 illustrates the process after the packet is folded back in the reverse direction of the daisy chain in the second embodiment. That is, after the process of S70, motor M2 sends a packet to driver D2 (S80). Then, driver D2 receives the packet (S81). Driver D2 then reads feedback F2 addressed to driver D2 from an area in the process data to which access is permitted (S82). The process of S82 is an example of acquiring the physical quantity detected in the motor corresponding to each driver from the area corresponding to the driver in the packet that has been folded back and transferred. Next, driver D2 sends a packet to motor M1 (S83) and controls motor M2 according to command C2 and feedback F2 acquired in the process of S66 (S84).

Next, motor M1 receives the packet (S85). Then, motor M1 writes the data detected by encoder E1 to the feedback F12 area addressed to driver D1 (S86). Note that, as described in FIG. 12, in the control system 100B, if driver D1 does not use the feedback F12 area and only uses the feedback F11 area, motor M1 does not need to execute the process of S86. Then, motor M1 sends the packet addressed to driver D1 (S87).

Next, driver D1 receives the packet (S88). Driver D1 then reads feedback F11 and F12 addressed to driver D1 from the accessible area in the process data (S89). The process of S89 is also an example of obtaining the physical quantities detected in the electric motors corresponding to each driver from the area corresponding to the driver in the packet that has been returned and transferred.

However, as described in FIG. 12, in the control system 100B, only one of the feedbacks F11 and F12 may be used. In that case, the driver D1 may read only one of the feedbacks F11 and F12. Next, the driver D1 sends a packet to the control device 10 (S90) and controls the motor M1 according to the command C1 and the feedbacks F11 and F12 acquired in the process of S59 (S91).

(Effects of the embodiment)
As described above, the control system 100B of this embodiment has a configuration in which the control device 10, the driver D1, the motor M1 (encoder E1), etc. are connected in a daisy chain by the communication line LC, similar to the first embodiment. However, in this embodiment, the control device 10
While a packet from makes one round trip through the daisy chain, the following processes 1 to 3 are executed in the control device 10 and the corresponding slave node.

(1) The control device 10 transmits commands including target values to the driver D1, etc., and the driver D1, etc., receives the commands.

(2) The motor M1, etc. writes the feedback information measured by the encoder E1, etc., into the feedback F1, etc. area of the packet.

(3) The motor M1 etc. obtains the feedback written by the motor M1 etc. from the feedback F1 etc. area of the packet (physical quantity detected by the encoder E1 etc.).

As a result, in the control system 100B including multiple drivers D1, motors M1 (encoders E1), etc., the drivers D1, etc. can control the motors M1, etc. with better response than in the case of the control system 100A illustrated in the first embodiment.

In this embodiment, as illustrated in Figures 2 to 7, in the daisy chain, it is necessary that the driver D1, etc. is located closer to the control device 10 than the motor M1, etc. that is to be controlled. In other words, in the daisy chain, the driver D1, etc. is located closer to the control device 10 than the motor M1, etc. that is to be controlled, and is connected to the daisy chain structure. This makes it possible to give instructions to the driver D1, etc., and to provide feedback from the motor M1, etc. to the driver D1, etc., in one round trip packet.

<Other embodiments>
<Additional Notes>
1. A plurality of control mechanisms (M1 to M4, D1 to D4) including motors (M1 to M4) each having a driver (D1 to D4) for driving the motor and an encoder (E1, E2) for detecting a physical quantity related to the rotation of the motor;
A control device (100) that controls the plurality of control mechanisms,
the drivers, the motors, and the control devices included in the plurality of control mechanisms are connected to a network (N1) having a daisy chain structure capable of packet transfer and supplying power to the encoders,
the control device (100) sets commands addressed to each driver in an area corresponding to each driver (D1 to D4) of the plurality of control mechanisms in the packet, and transmits the packet to the next connection destination in the daisy chain structure;
Each driver (D1 to D4) of the plurality of control mechanisms obtains a command addressed to itself from the control device from a region corresponding to itself in a packet received from a source of the daisy chain structure, and transmits the received packet to a next destination in the daisy chain structure;
A control system (100, 100A, 100B) in which each electric motor (M1 to M4) of the multiple control mechanisms sets a physical quantity detected by an encoder possessed by each electric motor in an area corresponding to the control mechanism in the received packet, and transmits the received packet to the next destination in the daisy chain structure.

10 Control device 100, 100A, 100B Control system D1, D2, D3, D4 Driver E1, E2, E3, E4 Encoder LC Communication line LP1, LP2 Power line M1, M2, M3, M4 Motor SN1, SN2 Sensor

Claims (10)

A plurality of control mechanisms including a driver for driving an electric motor and an electric motor having an encoder for detecting a physical quantity related to the rotation of the electric motor;
A control device that controls the plurality of control mechanisms,
the drivers, the motors, and the control devices included in the plurality of control mechanisms are connected to a network having a daisy chain structure capable of packet transfer and power supply to the encoders,
the control device sets a command addressed to each driver in an area corresponding to each driver of the plurality of control mechanisms within the packet, and transmits the packet to a next connection destination in the daisy chain structure;
Each driver of the plurality of control mechanisms obtains a command addressed to itself from the control device from a region corresponding to itself in a packet received from a source of the daisy chain structure, and transmits the received packet to a next destination in the daisy chain structure;
A control system in which each electric motor of the multiple control mechanisms sets a physical quantity detected by an encoder possessed by each electric motor in an area corresponding to the respective electric motor in a received packet, and transmits the received packet to a next destination in the daisy chain structure. The packet is forwarded back at the end of the daisy-chain network,
2. The control system according to claim 1, wherein each driver of the plurality of control mechanisms acquires the physical quantity detected in the electric motor corresponding to each driver from a region corresponding to the driver in the packet that is folded back and transferred. The control system according to claim 1 or 2, wherein in each of the plurality of control mechanisms, the driver is connected in a daisy chain configuration at a position closer to the control device than the corresponding electric motor. The control device is connected to a start point of the daisy chain structure and transmits the packet;
While the transmitted packet is traveling back and forth between the terminal end of the daisy chain structure, each motor of the plurality of control mechanisms sets the physical quantity in the received packet;
After the transmitted packet has traveled back and forth once between the terminal of the daisy chain structure, the control device re-transmits the packet that has traveled back and forth once;
The control system according to claim 1 , wherein each driver of the plurality of control mechanisms acquires the physical quantity detected in the electric motor corresponding to each driver from a region corresponding to the driver in the retransmitted packet. and one or more sensors connected to the daisy chain network.
A control system as claimed in any one of claims 1 to 4, wherein the one or more sensors set detected data in an area corresponding to the sensor in a packet received from a sender of the daisy chain structure, and transmit the received packet to a next destination in the daisy chain structure. A plurality of control mechanisms including a driver for driving an electric motor and an electric motor having an encoder for detecting a physical quantity related to the rotation of the electric motor;
A control device that controls the plurality of control mechanisms,
the drivers, the motors, and the control devices included in the plurality of control mechanisms are connected to a network having a daisy chain structure capable of packet transfer and power supply to the encoders,
the control device sets a command addressed to each driver in an area corresponding to each driver of the plurality of control mechanisms within the packet, and transmits the packet to a next connection destination in the daisy chain structure;
Each of the electric motors of the plurality of control mechanisms sets a physical quantity detected by an encoder of the electric motor in an area corresponding to the electric motor in the received packet, and transmits the received packet to a next destination in the daisy chain structure.
A driver that obtains a command addressed to itself from the control device from an area corresponding to itself in a packet received from a sender in the daisy chain structure, and transmits the received packet to the next destination in the daisy chain structure. The packet is forwarded back at the end of the daisy-chain network,
7. The driver according to claim 6, wherein the physical quantity detected in the electric motor corresponding to each of the drivers is obtained from a region corresponding to the driver in the packet that has been folded back and transferred. A plurality of control mechanisms including a driver for driving an electric motor and an electric motor having an encoder for detecting a physical quantity related to the rotation of the electric motor;
A control device that controls the plurality of control mechanisms,
the drivers, the motors, and the control devices included in the plurality of control mechanisms are connected to a network having a daisy chain structure capable of packet transfer and power supply to the encoders,
the control device sets a command addressed to each driver in an area corresponding to each driver of the plurality of control mechanisms within the packet, and transmits the packet to a next connection destination in the daisy chain structure;
In a network having a daisy chain structure, a driver of each of the plurality of control mechanisms obtains a command addressed to itself from the control device from a region corresponding to itself in a packet received from a source of the daisy chain structure, and transmits the received packet to a next destination in the daisy chain structure.
An electric motor that sets a physical quantity detected by an encoder attached to itself in an area corresponding to itself in a received packet, and transmits the received packet to the next destination in the daisy chain structure. A plurality of control mechanisms including a driver for driving an electric motor and an electric motor having an encoder for detecting a physical quantity related to the rotation of the electric motor;
A control device for a control system including:
the drivers, the motors, and the control devices included in the plurality of control mechanisms are connected to a network having a daisy chain structure capable of packet transfer and supplying power to the encoders;
Each driver of the plurality of control mechanisms obtains a command addressed to itself from the control device from a region corresponding to itself in a packet received from a source of the daisy chain structure, and transmits the received packet to a next destination in the daisy chain structure;
In a network having a daisy chain structure, each electric motor of the plurality of control mechanisms sets a physical quantity detected by an encoder of the respective electric motor in an area corresponding to the respective electric motor in the received packet, and transmits the received packet to a next destination in the daisy chain structure.
a control device that sets commands addressed to each driver in an area corresponding to each driver of the plurality of control mechanisms within the packet, and transmits the packet to the next connection destination in the daisy chain structure; A plurality of control mechanisms including a driver for driving an electric motor and an electric motor having an encoder for detecting a physical quantity related to the rotation of the electric motor;
A control method for a control system including a control device that controls the plurality of control mechanisms,
the drivers, the motors, and the control devices included in the plurality of control mechanisms are connected to a network having a daisy chain structure capable of packet transfer and power supply to the encoders,
the control device sets a command addressed to each driver in an area corresponding to each driver of the plurality of control mechanisms within the packet, and transmits the packet to a next connection destination in the daisy chain structure;
Each driver of the plurality of control mechanisms obtains a command addressed to itself from the control device from a region corresponding to itself in a packet received from a source of the daisy chain structure, and transmits the received packet to a next destination in the daisy chain structure;
A control method in which each electric motor of the multiple control mechanisms sets a physical quantity detected by an encoder possessed by each electric motor in an area corresponding to itself in the received packet, and transmits the received packet to the next destination in the daisy chain structure.

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