KR20010011041A - servo drive system for motor and control method thereof - Google Patents

Abstract

PURPOSE: A servo drive system and a control method thereof are provided to transmit a control command from an upper controller to a servo driver at real time. CONSTITUTION: A serial real time communications interface(33) is installed at a high-order controller(30) and performs a real time serial communication through a serial real time communications interface protocol. A serial real time communications interface(33') is installed at a servo driver(35) and performs a real time serial communication through a serial real time communications interface protocol. The serial real time communications interface(33,33') are formed by a single chip. A connector connects the serial real time communications interface(33') to the serial real time communications interface(33). The connector includes an optical fiber. Two control motors(31) are connected to the servo driver(35).

Description

Servo drive system and control method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo drive system, and more particularly to a servo drive system including a motor, a servo drive for driving control of the motor, and an upper level controller for sending a predetermined control command to the servo drive.

Servo drive systems for driving control of motors are widely used as drive control units for driving and controlling them in various machine tools, semiconductor equipment, and various industrial machinery such as robots.

1 is a block diagram of a conventional servo drive system, and FIG. 2 is a partial detailed view of FIG. 1.

As shown in the drawing, the conventional servo drive system is mounted on the shaft of an industrial machine and serves simultaneously with supplying a current to the motor 1 and the motor 1 serving as a driving power source for driving the industrial machine. A servo drive 5 for driving control of the motor 1 by adjusting the amount of current and the phases of which are applied, and an upper controller 10 for sending control commands to the servo drive 5;

When the industrial machine to drive control has multiple axes, as shown, the motor 1 is mounted on each axis and the servo drive 5 for driving control of the motor 1 is provided. The plural servo drives 5 are connected to each other.

The servo drive 5 controls the inverter module 5 in accordance with a control command from the upper controller 10, and receives a feedback signal from the motor 1 and feeds it back to the upper controller 10. And an inverter module 7 for generating a current to be supplied to the motor 1 based on a control command from the upper controller 10 under the control of the control module 6. Here, the upper controller 10 and the servo drive 5 are connected to each other through a coaxial cable.

According to the above configuration, the upper controller 10 grasps the current position value through the feedback signal from the servo drive 5 and calculates the target position value. The target position value is converted into a pulse command or a voltage command and provided to the servo drive 5. The control module 6 of the servo drive 5 analyzes the provided control command and performs a control loop according to the interrupt generated for each control cycle to control the inverter module 7, and the inverter module 7 controls the control module 6. A predetermined current is supplied to the motor 1 under the control of ().

Here, the control command is an error occurs in the process of being converted into a pulse or voltage by the upper controller 10, the process transmitted to the servo drive 5 through the coaxial cable, and the process analyzed by the servo drive (5) The command may be distorted by external noise.

On the other hand, the control command that the servo drive 5 receives from the host controller 10 is a simple I / O command such as a position command profile and an operation start stop for moving each axis, and the actual drive is performed by the servo drive 5. It is made by an operation program built in the control module 6. Thus, in order for the servo drive 5 to drive control the motor 1, the user must set and input various parameters of the operation program built in the control module 6 of the servo drive 5, respectively. In addition, the upper level controller 10 merely provides a control command to the servo drive 6, and in addition to the simple error occurrence information, information on the contents of the error and the current operating state of the motor 1 cannot be provided.

In practice, in the industrial field, the upper controller 10 and the servo drive 6 are usually remotely installed, so when an error occurs, the user can go directly to the remotely located servo drive 6 to find out what error has occurred. Analyze, check and respond.

Furthermore, if the industrial machinery to be driven and controlled is multi-axis, the cost increase is significant because the upper controller 10 and the servo drive 5 should be connected by coaxial cables, respectively. Since the control command provided must be transmitted in the form of a pulse command or a voltage command, it is difficult for the upper controller 10 to transmit the control command at the same time, so that complete synchronous control is virtually impossible.

Meanwhile, a two-axis servo drive system has been proposed in which one servo drive is connected to two motors to control them. In view of the fact that the two-axis servo drive system can control two times as much as the one axis, the two-axis servo drive system is an advanced technology compared to the one-axis servo drive system described above, but it is necessary to transmit control commands from the host controller. The basic configuration is the same as that of the 1-axis servo drive system, so the problem still exists.

Accordingly, an object of the present invention is to provide a servo drive system capable of transmitting in real time a control command from an upper level controller to a servo drive.

Another object of the present invention is to provide a servo drive system capable of accurate transmission by reducing errors and noise in transmitting control commands from the host controller to the servo drive.

Another object of the present invention is to provide a servo drive system capable of two-way communication between an upper controller and a servo drive.

1 is a block diagram of a conventional servo drive system,

2 is a partial detail view of FIG.

3 is a block diagram of a servo drive system according to the present invention;

4 is a block diagram of a SERCOS interface according to the present invention;

5 is a block diagram of a servo drive system having a SERCOS ring in accordance with the present invention;

6 is a flowchart illustrating a process of transmitting a control command to a servo drive by an upper controller according to the present invention;

FIG. 7 is a flowchart illustrating a process in which errors and diagnostics are transmitted from a servo drive to an upper controller according to the present invention.

* Explanation of symbols for the main parts of the drawings

30: upper controller 31; motor

33,33 ': SERCOS interface 35: Servo Drive

41: bus interface 42: dual port RAM

43: telegram processing unit 44: serial interface

The object is provided in the servo drive according to the present invention in a servo drive system including a motor, a servo drive for driving control of the motor, and an upper level controller for outputting a control command to the servo drive. SERCOS interface, which is a communication interface for real-time serial communication through SERCOS (Serial, Real-time, Communications Interface) protocol; A SERCOS interface provided in the servo drive, the SERCOS interface being a communication interface for real time serial communication through a SERCOS (Serial, Real-time, Communications Interface) protocol; And a connector connecting the two SERCOS interfaces.

Here, at least two controlled motors are connected to the servo drive, and the connector is preferably an optical fiber connector.

The SERCOS interface stores a bus interface for exchanging data with the inside, a serial interface for serial communication with the outside, data transmitted through the bus interface, and data transferred through the serial interface. And a data processing unit for processing the data stored in the memory into a packet capable of serial communication through the serial interface, and restoring a packet transmitted from the outside through the serial interface, wherein the memory has a dual port. It is effective to be dual port RAM.

In addition, the SERCOS interface is implemented as a single chip, the single chip is any one of an Application Specific IC (ASIC), a Field Programmable Gate Array (FPGA), and an Electrically Programmable Logic Devices (EPLD), in particular SERCON410B which is a communication IC. It is preferable.

In another aspect of the present invention, there is provided a control method of a servo drive system including a motor, a servo drive for driving control of the motor, and an upper level controller for outputting a control command to the servo drive. And providing an upper level controller with a SERCOS interface, which is a communication interface for real-time serial communication through SERCOS (Serial, Real-time, Communications Interface) protocol; And a transmitting step of transmitting a control command from the upper controller to the servo drive by serial data communication using the SERCOS communication protocol.

Here, at least two controlled motors are connected to the servo drive, and the transmitting step is performed for each of the two motors, and connecting the two interfaces to an optical fiber connector; It is preferable to include the step of transmitting through the optical fiber connector.

The transmitting may include storing a control command from the microprocessor of the upper controller through the bus interface; It is effective to further include processing the stored control command into a serial communication capable packet.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of a servo drive system according to the present invention, and FIG. 4 is a block diagram of a SERCOS interface according to the present invention.

As shown, the servo drive system according to the present invention is mounted on the shaft of the industrial machine, and supplies a current to the motor 31 and the motor 31, which serves as a driving power source for driving the industrial machine. And a servo drive 35 for driving control of the motor 31 by adjusting the amount of current and phase supplied, and an upper controller 30 for sending control commands to the servo drive 35.

The upper controller 30 and the servo drive 35 are connected by an optical fiber connector, and SERCOS interfaces 33 and 33 'are provided for real-time serial communication through the SERCOS (Serial Real-time COmmunications System) protocol.

SERCOS is a serial data communication protocol adopted as the International Electrotechnical Commission IEC-1491 for motion control. For SERCOS communication, a predetermined interface must be provided, which is called a SERCOS interface.

In more detail, the SERCOS interface 33 decodes the data to be transmitted through the serial interface 44 and the serial interface 44 for serial communication with the outside and the data received through the serial interface 44. Data processing unit 43, a bus interface 41 for exchanging data with a microprocessor (not shown) provided in the upper controller 30, and data can be simultaneously read and written through two ports, thereby enabling data communication. It includes Dual-port RAM.

The SERCOS interface 33 'provided in the servo drive 35 also has the same configuration as the SERCOS interface 33 provided in the upper controller 30. Therefore, "'" is attached to the upper right of the reference number and detailed description is omitted. do.

The SERCOS interfaces 33 and 33 'can be implemented in a single chip using application specific ICs (ASICs), field programmable gate arrays (FPGAs), and electrically programmable logic devices (EPLDs), in particular Thomson. SERCON410B, a communication IC developed by the company, is used.

The topology of the network configuration method is determined according to the communication protocol. Since the topology of SERCOS is in the shape of a ring, when the industrial machinery to be driven is controlled in multiple axes, the system forms a SERCOS ring as shown in FIG. 5. This is made up.

According to the configuration as described above, as shown in Figure 6, the process of transmitting the control command to the servo drive 35, the upper controller 30 is as follows.

The upper controller 30 operates according to the SERCOS communication protocol. In more detail, the microprocessor (not shown) of the upper controller 30 is provided from the servo drive 35 in the previous stage through the bus interface 41 so as to provide a dual port. The current position value stored in the RAM 42 is read (601). Based on the read current position value, the microprocessor calculates the target position value (602) and executes the control loop accordingly (603). The control command output according to the control loop execution is written to the dual port RAM 42 through the bus interface 41. The telegram processing unit 43 converts the control command into a telegram, and the telegram is sent out through the serial interface 44 and transmitted to the SERCOS interface provided in the servo drive 35 through the optical fiber connector 605. Here, the telegram means a data processing packet for serial communication by the SERCOS communication protocol.

In addition, since the servo drive 35 is connected to the two-axis motor 31, the above steps are repeated to transfer control commands to the remaining axes (606).

On the other hand, the servo drive 35 is also operated by the SERCOS communication protocol, the telegram including the control command transmitted from the upper controller 30 is a serial interface 44 'provided in the SERCOS interface 33' of the servo drive 35. The microprocessor (not shown) provided in the servo drive 35 reads the position information feedback signal data of the motor 31 and receives the dual port RAM 42. ') Is transmitted to the telegram processing unit 43', and the telegram processing unit 43 'is processed into a telegram to send the position information feedback signal data to the upper controller 30 (608).

The received control command is transmitted to the microprocessor through the telegram processing unit 43 ', the dual port RAM 42' and the bus interface 33, and analyzed (609), and then the control loop is executed (610).

Meanwhile, the telegram in which the position information feedback signal data is written is sent out through the serial interface 44 'and transmitted to the upper controller 33 through the optical fiber connector (611).

Subsequently, as shown in FIG. 7, an error and control states (diagnostics) are transmitted from the servo drive 35 to the upper controller 30 as follows.

First, information on errors or current control states (diagnostics) generated while the servo drive 35 drives the motor 31 is controlled by a microprocessor (not shown) provided in the servo drive 35. Error or control status information data is written to the dual port RAM 42 'via the bus interface 41' (701). The telegram processing unit 43 processes the error or control state information data into the telegram from the dual port RAM 42 'and sends it out through the serial interface 44', which is sent to the upper controller 30 through the optical fiber connector. Is sent (702).

Subsequently, the servo drive 35 displays an error occurrence signal or stops the motor 31 (703).

The host controller 30 receives the error or control state information data through the serial interface 44 and restores the data through the telegram processing unit 43, and then passes through the dual port RAM 42 and the bus interface 41. It is provided with a microprocessor (not shown) and the microprocessor analyzes it and displays its contents for viewing by the user (705). The display may be any of various types. However, since the host controller 30 is usually implemented as a computer system, the user may display the monitor and generate an alarm.

Then check whether the remaining axis has been executed or not, and repeat the above steps.

As described above, in the servo drive system according to the present invention, since the upper controller 30 transmits a control command to the servo drive 35 by digital data communication using the SERCOS communication protocol, it is converted into a conventional pulse command or voltage command and then transmitted. There is no error caused by analog communication.

In addition, since SERCOS protocol supports real-time serial communication through optical fiber transmission, the upper controller and servo drive are connected by optical fiber connector. The diameter of the optical fiber is shorter, lighter and cheaper than the coaxial cable, and it is almost unaffected by noise. Can be transmitted, enabling synchronous control.

Furthermore, since the SERCOS protocol supports two-way communication between the upper controller 30 and the servo drive 35, the upper controller 30 receives only simple I / O information such as start and stop, and the upper controller 30 receives the motor by the servo drive 35. While the control state of (31) was not known, not only the feedback information from the motor 31 but also the error occurrence and the current control state information can be exchanged.

Therefore, the user can check the control state and the operation state through the upper controller 30 even if the user does not go directly to the servo drive 35 in the remotely located workplace.

As described above, according to the present invention, the control command provided from the host controller to the servo drive is transmitted in real time without any influence of noise as digital data without error, and the two-way communication between the host controller and the servo drive is possible. Provided are a servo drive system and a method of controlling the same, which transmit information on errors and diagnostics generated during drive control of a motor to a higher controller as digital data.

Claims (12)

A servo drive system comprising a motor, a servo drive for driving control of the motor, and a host controller for outputting a control command to the servo drive. A SERCOS interface provided in the servo drive, the SERCOS interface being a communication interface for real time serial communication through a SERCOS (Serial, Real-time, Communications Interface) protocol; A SERCOS interface provided in the servo drive, the SERCOS interface being a communication interface for real time serial communication through a SERCOS (Serial, Real-time, Communications Interface) protocol; And And a connector connecting the two SERCOS interfaces. The method of claim 1, And at least two controlled motors are connected to the servo drive. The method according to claim 1 or 2, The connector is a servo drive system, characterized in that the optical fiber connector. The method of claim 3, wherein The SERCOS interface is a bus interface for exchanging data with the inside, a serial interface for serial communication with the outside, a memory for storing data transmitted through the bus interface and data transmitted through the serial interface. And a data processing unit processing the data stored in the memory into a packet capable of serial communication through the serial interface, and restoring a packet transmitted from the outside through the serial interface. The method of claim 4, wherein The memory is a servo drive system, characterized in that the dual port RAM (dual port RAM). The method of claim 5, The SERCOS interface is a servo drive system, characterized in that implemented in a single chip. The method of claim 6, The single chip is any one of an application specific IC (ASIC), a field programmable gate array (FPGA), and electrically programmable logic devices (EPLD). The method of claim 6, The single chip is a servo drive system, characterized in that the communication IC SERCON410B. In the control method of the servo drive system including a motor, a servo drive for driving control of the motor, and a host controller for outputting a control command to the servo drive, Providing each of the servo drive and the host controller with a SERCOS interface, which is a communication interface for real-time serial communication through SERCOS (Serial, Real-time, Communications Interface) protocol; And a transmission step of transmitting a control command from the upper controller to the servo drive by serial data communication using the SERCOS communication protocol. The method of claim 9, At least two controlled motors are connected to the servo drive, and the transmitting step is performed for each of the two motors. The method according to claim 9 or 10, The transmitting step, Connecting both interfaces to an optical fiber connector; And transmitting through the optical fiber connector. The method of claim 11, The transmitting step, Storing a control command from the microprocessor of the host controller through the bus interface; And processing the stored control command into a serial communication packet.