JP2009258949A - Motor control system and connection determination method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor control system that allows synchronous control to be easily performed and the setting of a master and a slave to be done, by merely connecting two servo amplifiers with a communication cable. <P>SOLUTION: The servo amplifier 1 (2) has an encoder communication cable 5 (6) for a driven servomotor 3 (4), connected at one two-way communication means 15 (26), and the communication cable 7, connected from another two-way communication means 16 to a two-way communication means 25. A device control part 11 (21) selectively connects the two-way communication means 15 (25) to an inter-device communication part 13 (23) or encoder communication part 12 (22) via a selector 4 (24) by a selector switching signal 11d (21d) output, at the start of communication and automatically determines a master or slave in synchronous control. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor control system that automatically determines the connection state of a master and a slave in synchronous control of two servo amplifiers connected by a communication cable.

  In general, when two servo amplifiers are synchronously controlled, one servo amplifier is operated as a master and the other as a slave, and a control command from a host controller is input to the servo amplifier on the master side for control.

  At that time, the master side (servo amplifier) calculates and determines the control amount to be supplied to the slave side (servo amplifier) in response to the command from the host controller, drives the motor connected to its own device, and The motor drive command is transferred to the slave side.

  On the other hand, the slave side drives the servo motor on the slave side in accordance with the command transferred from the master side, and transfers status information such as feedback information, motor drive status, and the presence / absence of an error to the master side. On the master side, the status information transferred from the slave side and the status information in its own device are combined and fed back to the host controller. As described above, the synchronization control is realized by sharing the information held by the two servo amplifiers.

In recent years, as a method of driving two-axis servo motors synchronously, one servo control device that has received a position command from the controller transmits the position command to the other servo control device to synchronize the two-axis servo motor. In the two-axis synchronous control device that is driven in this manner, one servo control device inputs the position from the position detector in synchronization with the transmission completion timing and the other servo control device inputs the position from the position detector. A two-axis synchronous control device including the communication means has been proposed (see, for example, Patent Document 1).
JP 2006-285752 A

  In order to control the two servo amplifiers synchronously, the cables are connected to each other to transmit and receive control data. When starting communication such as when the power is turned on, which servo amplifier sends the request transmission first. It is necessary to decide. That is, before starting communication, it is necessary to set the two servo amplifiers to distinguish between the master and slave of the control, such as master or slave. If the settings are incorrect, normal synchronous control cannot be performed.

  For example, if both servo amplifiers are mistakenly set to the same setting, data cannot be transmitted / received successfully (information cannot be shared), and synchronization control cannot be performed normally. If both servo amplifiers are set to send a request first, the request output signals collide with each other on the communication cable due to the start of communication, causing excessive stress on the communication transceiver, etc., and damaging the device. There was a possibility.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to provide a motor control system that can be set as a master and a slave by simply connecting two servo amplifiers with a communication cable and can easily perform synchronous control. .

  In order to solve the above problem, the motor control system according to claim 1 is a motor control system in which two servo amplifiers are connected to each other to perform synchronous control, wherein the servo amplifier includes position information of a servo motor to be driven. Two-way communication means connected to and communicating with the encoder or the other servo amplifier, the encoder communication unit for controlling the two-way communication with the encoder, and the two-way communication control with the other servo amplifier An inter-device communication unit, the bidirectional communication means, a selector for connecting the encoder communication unit or the inter-device communication unit, position information from the encoder communication unit, and the other motor from the inter-device communication unit A device controller that calculates the control amount based on the control information and gives a drive signal to the connected servo motor for control. Each servo amplifier is connected to an encoder of a servo motor that is driven to one of the bidirectional communication means, and the other bidirectional communication means is connected by a communication cable. A bidirectional communication means and an inter-device communication unit or an encoder communication unit are selectively connected by the selector by a selector switching signal output at the start of communication, and a master and a slave in synchronization control are automatically determined.

  In the motor control system according to claim 2, when the bidirectional communication means and the encoder communication unit are connected by switching the selector at the start of communication, the encoder communication unit transmits a request to the encoder, and the encoder The servo amplifier that receives the response is determined as the master for synchronous control, and the servo amplifier that does not receive the response is determined as the slave.

  Furthermore, the motor control system connection determination method according to claim 3 is the motor control system according to claim 1 or 2, wherein the servo amplifier is encoded by a selector switching signal output from the device control unit at the start of communication. Steps 1 and 1 for connecting a communication unit and a bidirectional communication unit, setting a request command in the encoder communication unit, transmitting a request to a cable connected to the bidirectional communication unit, and determining whether or not there is a response. If there is a response in step 2, the inter-device communication unit and the other two-way communication means are connected by the selector switching signal, and the presence or absence of data for confirming the connection according to the inter-device communication protocol in the inter-device communication unit is determined. If there is no response in step 1, the encoder communication unit and the other side are In step 3 and step 3 in which a bidirectional communication unit is connected, a request command is set in the encoder communication unit, a request is transmitted to the cable connected to the bidirectional communication unit, and the presence or absence of a response is determined. When there is a response, the inter-device communication unit and the bidirectional communication means are connected by the selector switching signal, the connection confirmation data is set in the inter-device communication unit, and the presence or absence of a response from the connection destination device is provided. Either master or slave is estimated based on the presence or absence of a response in step 1. If there is reception in step 2, it is determined as master, if there is a response in step 3, and if there is a response in step 4, it is determined as slave In steps 2, 3, and 4, if there is no reception or no response, it is determined that the connection is abnormal.

  According to the motor control system and the connection determination method according to claim 1-3, the encoder and the communication cable are connected to the two-way bidirectional communication means, and the connection destination of the encoder communication unit and the inter-device communication unit is selected by the selector. Since switching is performed, it is possible to prevent the request signals from colliding with each other on the communication cable at the start of communication, and to prevent damage to the apparatus. Further, since the master and slave in the synchronous control can be automatically determined by simply connecting the encoder and the communication cable to the two systems of bidirectional communication means, it is not necessary to set the master and slave in advance.

  In this way, a motor control system that can easily perform synchronous control can be provided simply by connecting the encoder and communication cable to the two-way bidirectional communication means of the servo amplifier.

In a motor control system that performs synchronization control by connecting two servo amplifiers to each other, the servo amplifier is connected to an encoder that detects position information of the servo motor to be driven or the other servo amplifier to perform communication. Bi-directional communication means, an encoder communication section that performs bi-directional communication control with the encoder, an inter-device communication section that performs bi-directional communication control with the other servo amplifier, the bi-directional communication means, and the encoder communication The control amount is calculated based on the selector that connects the communication unit or the inter-device communication unit, the position information from the encoder communication unit, and the other motor control information from the inter-device communication unit, and the connected servo motor It is equipped with a device control unit that gives a drive signal to control, and each servo amplifier is driven to one of the bidirectional communication means The servo motor encoder is connected, and the other bidirectional communication means is connected by a communication cable, and the device control unit is configured to transmit the bidirectional communication unit and the inter-device communication unit or the device by a selector switching signal output at the start of communication. The encoder communication unit is selectively connected by the selector, and the master and slave in the synchronization control are automatically determined. Hereinafter, embodiments will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram of a main part of the motor control system of the present invention. The motor control system includes one host controller, two servo amplifiers and servo motors, and communication cables.

  In FIG. 1, a host controller 8 is connected to the servo amplifier 1, the servo amplifier 1 and the servo motor 3 are connected by an encoder communication cable 5, and the servo amplifier 2 and the servo motor 4 are connected by an encoder communication cable 6. The servo amplifier 1 and the servo amplifier 2 are connected by a communication cable 7. The configuration of the two servo amplifiers 1 and 2 is the same, and the servo amplifier 1 will be described below.

  The servo amplifier 1 includes a device control unit 11, an encoder communication unit 12, an inter-device communication unit 13, a selector 14, and two systems of bidirectional communication means 15 and 16, and the components will be described below. .

  The device control unit 11 is composed of a microcomputer or the like, and based on the control information 8a input from the host controller 8, determines the motor position command of the own device and the position command to be transmitted to the servo amplifier 2, and transmits the position command. Inter-device transmission data 11c obtained by adding command information such as drive start / stop to the command is generated and output to the inter-device communication unit 13. Further, the inter-device reception data 13b is read from the inter-device communication unit 13, and the feedback data 11e obtained by synthesizing the operation state of the servo amplifier 2 and the operation state of the own device included therein is output to the host controller 8. On the other hand, the speed / torque is calculated from the current position information of the servo motor 3 included in the motor position command and the encoder reception data 12b, and the motor drive signal 11a is supplied to the servo motor 3. Then, at the start of communication such as immediately after the power is turned on, the connection destination is selected by the selector 14 and the master / slave is automatically determined by communication using the encoder communication unit 12 or the inter-device communication unit 13. Details will be described later.

  The encoder communication unit 12 controls the protocol of encoder communication, and is configured by a dedicated circuit such as a custom LSI or a microcomputer. Encoder transmission data 11b such as a request command to be transmitted to the encoder and an address of data read from the encoder is input from the apparatus control unit 11, and an encoder communication control signal 12a such as parallel-serial conversion of the input data and a control signal of the serial communication IC is received. Generate and output to the selector 14. Also, the encoder communication reception signal 14 c input from the selector 14 is serial-parallel converted to generate encoder reception data 12 b and output it to the device control unit 11. The device that communicates with the encoder communication unit 12 is not limited to an encoder, and may be a device that can acquire position information of a control target such as an external scale.

  The inter-device communication unit 13 performs protocol control for data transmission / reception between the servo amplifier 1 and the servo amplifier 2 and is configured by a dedicated circuit such as a custom LSI. The inter-device transmission data 11c is input from the device control unit 11, A control signal for parallel-serial conversion of input data and a serial communication IC is generated and output to the selector 14. The inter-device communication reception signal 14d input from the selector 14 is serial-parallel converted to generate inter-device reception data 13b.

  The selector 14 connects the encoder communication unit 12 or the inter-device communication unit 13 to either the bidirectional communication unit 15 or the bidirectional communication unit 16 by a selector switching signal 11 d from the device control unit 11.

  The bidirectional communication unit 15 converts the control signal 14 a input from the selector 14 into a differential signal, transmits the differential signal to the encoder communication cable 5, and transmits the differential signal received from the encoder communication cable 5 to the bidirectional communication unit 15. The received signal 15a is output to the selector 14.

  The bidirectional communication means 16 is connected to the bidirectional communication means 25 of the other servo amplifier 2 via the communication cable 7, converts the control signal 14b input from the selector 14 into a differential signal, and transmits the differential signal to the communication cable 7. A differential signal received from the communication cable 7 is output to the selector 14 as a received signal 16a. The bidirectional communication means 15 and 16 are constituted by a serial communication IC represented by an RS485 transceiver.

  Here, the master / slave automatic determination sequence will be described with reference to FIGS. This automatic determination sequence starts operation at the start of communication. In FIG. 2, the process up to determination process 1 corresponds to step 1 of the present invention, the process up to determination process 2 corresponds to step 2, the process up to determination process 3 corresponds to step 3, and the process up to determination process 4 corresponds to step 4.

  First, in the switching process 1 (101), the encoder communication unit 12 and the bidirectional communication means 15 are connected by a selector switching signal 11d output from the device control unit 11. In the next communication process 1 (102), a request command is set in the encoder communication unit 12 and the request is transmitted to the cable connected to the bidirectional communication means 15.

  In the next determination process 1 (103), it is determined whether or not there is a response from the encoder in response to the request for communication process 1.

  If there is a response, the process branches to the switching process 2 (104), and if there is no response, the process branches to the switching process 3 (108). In the servo amplifier 1 according to the first embodiment, an encoder is connected to the bidirectional communication means 15, and there is a response from the encoder. In the switching process 2, the inter-device communication unit 13 and the bidirectional communication unit 16 are connected by the selector switching signal 11d. In the next determination process 2, it is determined whether or not data for confirming connection according to the inter-device communication protocol in the inter-device communication unit 13 is received.

  If there is reception, the process branches to process 1 (106). On the other hand, if there is no reception even after a sufficiently long time, a branch is made to processing 2 (107) as no reception. In the process 1, a response to the data received in the determination process 2 is transmitted, the own apparatus is determined as the master, and the automatic determination sequence is terminated.

Since the communication cable 7 is connected to the bidirectional communication means 16 of the servo amplifier 1 and the servo amplifier 2 is connected to the end of the communication cable 16 and data is received, the apparatus is determined to be the master. In process 2, error information that there is no reception from the counterpart device and synchronization control is not possible is fed back to the host controller 8 and the automatic determination sequence is terminated. In this way, the servo amplifier 1 can automatically determine that its own device is the master.

  Next, a description will be given of the master / slave automatic determination sequence portion of the servo amplifier 2 that is different in operation from the servo amplifier 1.

  In the determination process 1, the servo amplifier 2 branches to the switching process 3 (108) because there is no connection to the bidirectional communication means 25 and there is no response. In the switching process 3, the encoder communication unit 22 and the bidirectional communication means 26 are connected by a selector switching signal 21d output from the device control unit 21. In the next communication process 2 (109), a request command is set in the encoder communication unit 22 and the request is transmitted to the cable connected to the bidirectional communication means 26.

  In the determination process 3 (110), it is determined whether or not there is a response from the encoder with respect to the request of the communication process 2. If there is a response, the process branches to the switching process 4 (111), and if there is no response, the process branches to the process 3 (112). In process 3, an automatic disconnection is terminated by tripping due to an encoder unconnected error.

  Since the encoder is connected to the bidirectional communication means 26 of the servo amplifier 2 via the encoder communication cable 6 and there is a response, the process branches to the switching process 4. In the switching process 4, communication between devices is performed by the selector switching signal 21 d. The unit 23 and the bidirectional communication means 25 are connected. In the next communication process 3 (113), data for confirming the connection is set in the inter-device communication unit 23, and the data is transmitted to the cable connected to the bidirectional communication means 25.

  In the next determination process 4 (114), it is determined whether or not there is a response from the connection destination device to the transmission data of the communication process 3. If there is a response, the process proceeds to process 4 (115). If there is no response after a predetermined sufficiently long time, the process branches to switching process 5 (116) as no response. In process 4, the self apparatus is determined as a slave and the automatic determination sequence is terminated.

  Since the communication cable 7 is connected to the bidirectional communication means 25 of the servo amplifier 2 and the servo amplifier 1 is connected to the end of the communication cable 7 and there is a response, the apparatus is determined to be a slave. In process 5, the automatic determination sequence ends with a trip due to an error that there is no response from the counterpart device and synchronization control cannot be performed. In this way, the servo amplifier 2 can automatically determine that its own device is a slave.

  In this way, since the bidirectional communication means 16 of the servo amplifier 1 and the bidirectional communication means 25 of the servo amplifier 2 are connected by the communication cable 7 and are determined according to the automatic determination sequence, requests at the start of communication do not collide. Can prevent damage to the device. Further, by automatically determining the master / slave by each servo amplifier by the automatic determination sequence, the synchronization control can be performed without setting the master / slave in advance.

  The motor control system of the present invention is useful for an apparatus that is interconnected by a communication line and transmits / receives information in addition to a servo amplifier.

Block diagram of main parts of servo amplifier according to the first embodiment of the present invention Flowchart of automatic determination sequence in Embodiment 1 of the present invention

Explanation of symbols

1, 2 Servo amplifier 3, 4 Servo motor 5, 6 Encoder communication cable 7 Communication cable 8 Host controller 11, 21 Device control unit 12, 22 Encoder communication unit 13, 23 Inter-device communication unit 14, 24 Selector 15, 16, 25 , 26 Bidirectional communication means 8a Control command 11a, 21a Motor drive signal 11b, 21b Encoder transmission data 11c, 21c Inter-device transmission data 11d, 21d Selector switching signal 11e Feedback data 12a, 22a Encoder communication control signal 12b, 22b Encoder reception data 13a, 23a Inter-device communication control signal 13b, 23b Inter-device received data 14a, 14b, 24a, 24b Control signal 14c, 24c Encoder communication received signal 14d, 24d Inter-device communication received signal 15a, 1 a, 25a, 26a received signal

Claims (3)

In a motor control system that performs synchronous control by connecting two servo amplifiers together,
The servo amplifier is
Two-way bidirectional communication means for communicating by being connected to an encoder for detecting position information of a servo motor to be driven or the other servo amplifier;
An encoder communication unit that performs bidirectional communication control with the encoder;
An inter-device communication unit that performs bidirectional communication control with the other servo amplifier;
A selector that connects the bidirectional communication means and the encoder communication unit or the inter-device communication unit;
A device control unit that calculates a control amount based on position information from the encoder communication unit and the other motor control information from the inter-device communication unit, and gives a drive signal to the connected servo motor to perform control. Prepared,
Each servo amplifier is connected to an encoder of a servo motor that is driven to one of the bidirectional communication means, and the other bidirectional communication means is connected with a communication cable,
The device control unit selectively connects a bidirectional communication means and an inter-device communication unit or an encoder communication unit with the selector by a selector switching signal output at the start of communication, and automatically determines a master and a slave in synchronous control. Characteristic motor control system. When the bidirectional communication means and the encoder communication unit are connected by the selector at the start of communication,
The encoder communication unit transmits a request to the encoder,
The motor control system according to claim 1, wherein a servo amplifier that receives a response from the encoder is determined as a master for synchronous control, and a servo amplifier that does not receive a response is determined as a slave. In the motor control system according to claim 1 or 2,
At the start of communication, the servo amplifier connects the encoder communication unit and bidirectional communication means by the selector switching signal output from the device control unit, sets a request command in the encoder communication unit, and connects the cable connected to the bidirectional communication means. Step 1 for sending a request to the server and determining whether or not there is a response;
If there is a response in step 1, the inter-device communication unit and the other two-way communication means are connected by the selector switching signal, and the presence / absence of reception of data for confirming the connection according to the inter-device communication protocol in the inter-device communication unit is determined. Step 2 and
If there is no response in step 1, the encoder communication unit and the other bidirectional communication means are connected by the selector switching signal, a request command is set in the encoder communication part, and a request is made to the cable connected to the bidirectional communication means. Step 3 for determining whether or not there is a response;
If there is a response in step 3, the inter-device communication unit and the bidirectional communication means are connected by the selector switching signal, connection confirmation data is set in the inter-device communication unit, and the presence / absence of a response from the connection destination device is determined. With
Estimate either master or slave depending on whether there is a response in step 1. If there is a reception in step 2, confirm as master, if there is a response in step 3, and if there is a response in step 4, confirm as slave In steps 2, 3, and 4, the connection determination method of the motor control system determines that the connection is abnormal when there is no reception or no response.

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